Finite-temperature magnetization transport of the one-dimensional anisotropic Heisenberg model

We study finite-temperature magnetization transport in a one-dimensional anisotropic Heisenberg model, focusing in particular on the gapped phase. Using numerical simulations by two different methods, a propagation of localized wavepackets and a study of nonequilibrium steady states of a master equation in a linear-response regime, we conclude that the transport at finite temperatures is diffusive. With decreasing temperature the diffusion constant increases, possibly exponentially fast. This means that at low temperatures the transition from ballistic to asymptotic diffusive behavior happens at very long times. We also study dynamics of initial domain wall like states, showing that on the attainable time scales they remain localized.Comment: 14 pages, 11 figures; v3: few minor correction

Excitation energy transfer efficiency: equivalence of transient and stationary setting and the absence of non-Markovian effects

We analyze efficiency of excitation energy transfer in photosynthetic complexes in transient and stationary setting. In the transient setting the absorption process is modeled as an individual event resulting in a subsequent relaxation dynamics. In the stationary setting the absorption is a continuous stationary process, leading to the nonequilibrium steady state. We show that, as far as the efficiency is concerned, both settings can be considered to be the same, as they result in almost identical efficiency. We also show that non-Markovianity has no effect on the resulting efficiency, i.e., corresponding Markovian dynamics results in identical efficiency. Even more, if one maps dynamics to appropriate classical rate equations, the same efficiency as in quantum case is obtained.Comment: 11 pages, 4 figure

Optimal number of pigments in photosynthetic complexes

We study excitation energy transfer in a simple model of photosynthetic complex. The model, described by Lindblad equation, consists of pigments interacting via dipole-dipole interaction. Overlapping of pigments induces an on-site energy disorder, providing a mechanism for blocking the excitation transfer. Based on the average efficiency as well as robustness of random configurations of pigments, we calculate the optimal number of pigments that should be enclosed in a pigment-protein complex of a given size. The results suggest that a large fraction of pigment configurations are efficient as well as robust if the number of pigments is properly chosen. We compare optimal results of the model to the structure of pigment-protein complexes as found in nature, finding good agreement.Comment: 20 pages, 7 figures; v2.: new appendix, published versio

Temporal Variability in the Incidence and Risk Factors for Pharyngocutaneous Fistula Development after Total Laryngectomy

Background: This study aimed to analyse the variability in the incidence of the pharyngocutaneous fistula (PCF), the most common complication following a total laryngectomy (TLE), and to identify the underlying causes for fluctuations in incidence rates. Methods: In the retrospective study, the annual PCF incidence data and comprehensive clinicopathologic data from 540 patients who underwent TLE between January 2004 and December 2022 were reviewed. Distinct peri ods of both high and low PCF incidence were identified. Within these periods, patients were categorized into groups with PCF (study groups) and without it (control groups). These groups were statistically compared based on potential risk factors for PCF development. The high-incidence periods were specially analysed for recurring risk factors and the corresponding corrective measures were reviewed. Results: The analysis revealed four high-incidence periods with an overall PCF incidence of 37.61%, along with three low-incidence periods in between with an overall incidence of 19.38%. Surgical wound infection (SWI) and a history of head and neck cancer alongside their related treatments were repeatedly identified as independent risk factors during high-incidence periods, with SWI being the most consistent predictor of PCF development. Conclusions: Continuous monitoring of PCF incidence is crucial, as it allows for the identification of emerging risk factors and the immediate implementation of corrective measures to mitigate these newly identified risk factors

The influence of cytotoxic drugs on the immunophenotype of blast cells in paediatric B precursor acute lymphoblastic leukaemia

Flow cytometry plays is important in the diagnosis of acute lymphoblastic leukaemia (ALL) and when antigen-specific immunotherapy is indicated. We have investigated the effects of prednisolone, vincristine, daunorubicin, asparaginase and methotrexate on the antigen expression on blast cells that could influence the planning of antigen-specific therapy as well as risk-based treatment assignment