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Background Coronavirus Disease 2019 (COVID-19) led to pandemic that affected almost all countries in the world. Many countries have implemented border restriction as a public health measure to limit local outbreak. However, there is inadequate scientific data to support such a practice, especially in the presence of an established local transmission of the disease. Objective To apply a metapopulation Susceptible-Exposed-Infectious-Recovered (SEIR) model with inspected migration to investigate the effect of border restriction as a public health measure to limit outbreak of coronavirus disease 2019. Methods We apply a modified metapopulation SEIR model with inspected migration with simulating population migration, and incorporating parameters such as efficiency of custom inspection in blocking infected travelers in the model. The population sizes were retrieved from government reports, while the number of COVID-19 patients were retrieved from Hong Kong Department of Health and China Centre for Disease Control (CDC) data. The R 0 was obtained from previous clinical studies. Results Complete border closure can help to reduce the cumulative COVID-19 case number and mortality in Hong Kong by 13.99% and 13.98% respectively. To prevent full occupancy of isolation facilities in Hong Kong; effective public health measures to reduce local R 0 to below 1.6 was necessary, apart from having complete border closure. Conclusions Early complete travel restriction is effective in reducing cumulative cases and mortality. However, additional anti-COVID-19 measures to reduce local R 0 to below 1.6 are necessary to prevent COVID-19 cases from overwhelming hospital isolation facilities.

Introduction The standard treatment for primary central nervous system lymphoma (PCNSL) involves induction methotrexate-based chemotherapy with or without consolidation whole brain radiotherapy (WBRT). As WBRT carries a substantial risk for cognitive impairment, alternative consolidation treatments have been used to reduce neurotoxicity, including reduced-dose WBRT (rdWBRT) or high-dose chemotherapy with autologous stem cell transplant (HDC-ASCT). In this study, we characterized cognitive functions in PCNSL patients achieving long-term remission following rdWBRT or HDC-ASCT. Methods PCNSL patients completed cognitive evaluations at diagnosis, post-induction chemotherapy, and yearly up to 5 years following rdWBRT or HDC-ASCT. Quality of life (QoL), white matter (WM) disease, and cortical atrophy (CA) on MRI were assessed at similar intervals. Results Performance was impaired on most cognitive tests at diagnosis. Linear mixed model analyses in each group showed statistically significant improvement from baseline up to year 3 in attention/executive functions, graphomotor speed, and memory; however, there was a decline in attention/executive functions and memory after year 3 in both groups. WM abnormalities increased over time in both groups, but more patients treated with rdWBRT developed CA and WM changes. There were no significant longitudinal group differences in cognitive performance or QoL. Conclusions Results indicated improvement in cognitive function up to 3 years post-treatment, but a decline at later time points and an increase in brain structure abnormalities in both groups. The findings suggest that rdWBRT and HDC-ASCT may be associated with delayed neurotoxicity in progression-free patients and underscore the need for long-term follow-up to characterize cognitive dysfunction in PCNSL patients.

Grade 4 gliomas, including glioblastoma, isocitrate dehydrogenase (IDH)-wild-type [GBM (IDH wt)], and astrocytoma, IDH-mutant, grade 4, are among the most aggressive primary brain tumors. The standard of care for GBM (IDH wt) and astrocytoma, IDH-mutant, grade 4 is maximum safe resection and radiation plus oral temozolomide (TMZ) followed by six cycles of TMZ. The study objective was to identify peripheral biomarkers that predict favorable outcomes and stratify patients likely to respond to treatment. Adults with biopsy-confirmed glioblastoma (based upon the 2016 World Health Organization classification) treated at Beth Israel Deaconess Medical Center (Boston, USA) between January 2018 and November 2021 were identified. Data on laboratory values (white blood cells, absolute neutrophil count, absolute lymphocyte count, red blood cells, hemoglobin and platelet count), molecular markers, including IDH1 R132H and methylguanine-DNA methyltransferase promoter methylation, and progression-free survival (PFS) and overall survival (OS) were collected retrospectively. Data were combined with those from two prior studies, resulting in a total of 263 patients. Leukopenia development during TMZ treatment was associated with increased PFS (P=0.008) and OS (P=0.03). Lymphopenia development during TMZ treatment was associated with increased PFS (P=0.05) and OS (P=0.007). Grade 3 thrombocytopenia during TMZ treatment was associated with decreased PFS (P=0.01) and OS (P=0.02). Patients who developed leukopenia alone during treatment had an increased OS compared with those with only lymphopenia development and those with both lymphopenia and leukopenia development (P=0.007). Lower baseline lymphocyte counts (<0.7 K/µl) prior to treatment was associated with improved OS (P=0.007), while increased baseline neutrophil counts (≥10.0 K/µl) prior to initiation of treatment were associated with worse OS (P=0.002). In conclusion, TMZ exposure may result in a leukocyte predominant bone marrow effect vs. a platelet predominant bone marrow effect. Clinically, leukopenia could indicate adequate TMZ dosing, with thrombocytopenia serving as a limiting factor in the ability to continue TMZ. Baseline counts may offer insights into which patients will benefit the most from treatment.

Magnetic fields and their dynamical interplay with matter in galaxy clusters contribute to the physical properties and evolution of the intracluster medium. However, the current understanding of the origin and properties of cluster magnetic fields is still limited by observational challenges. In this article, we map the magnetic fields at hundreds-kpc scales of five clusters RXC J1314.4-2515, Abell 2345, Abell 3376, MCXC J0352.4-7401, and El Gordo using the synchrotron intensity gradient technique in conjunction with high-resolution radio observations from the Jansky Very Large Array (JVLA) and the Karoo Array Telescope (MeerKAT). We demonstrate that the magnetic field orientation of radio relics derived from synchrotron intensity gradient is in agreement with that obtained with synchrotron polarization. Most importantly, the synchrotron intensity gradient is not limited by Faraday depolarization in the cluster central regions and allows us to map magnetic fields in the radio halos of RXC J1314.4-2515 and El Gordo. We find that magnetic fields in radio halos exhibit a preferential direction along the major merger axis and show turbulent structures at higher angular resolution. The results are consistent with expectations from numerical simulations, which predict turbulent magnetic fields in cluster mergers that are stirred and amplified by matter motions. The current understanding of the origin and properties of cluster magnetic fields is limited by observational challenges. Here, the authors show that magnetic field orientations of galaxy clusters, including radio relic and radio halos, can be derived via combination of synchrotron intensity gradient technique with radio observations.

Primary leptomeningeal melanoma (PLM) is a rare type of cancer that represents a major clinical and molecular diagnostic challenge. A definitive diagnosis requires consistent magnetic resonance imaging findings and cerebrospinal fluid (CSF) cytology. Due to the small number of malignant cells in the CSF, routine testing for mutations in the BRAF gene is difficult, which prevents the stratification of these patients to potentially beneficial therapies. We herein present the case of a 62-year old man with CSF cytology indicating PLM, where BRAF mutation testing, from cell-free (cf) tumor DNA isolated from the CSF and plasma was implemented to guide clinical decision making. Testing for BRAFV600E mutation from the CSF and plasma was technically feasible, yielded concordant results, and guided the treatment for this patient. This case suggests that mutation testing of cfDNA isolated from the CSF is technically feasible and may guide therapy in cases where a tissue diagnosis is not possible for PLM and other malignancies with defined oncogenic driver mutations.

Organic semiconductors in electronic devices usually have poor thermal conduction which could trap considerable amount of heat, inducing operational instability and reducing device lifetime, limiting commercialization potential. Despite the technological essence to understand and enhance device heat‐dissipation, related studies on organic semiconductors are very limited. In this study, the authors show that the scanning photothermal deflection technique can be employed to study the thermal transport in thin films of organic photovoltaic (OPV) polymers and bulk‐heterojunctions (BHJs), with a simple empirical correction for the extrinsic experimental configuration. Phonons are identified to dominate the thermal transport due to the low carrier mobility. For OPV semiconductors, the positive correlation between the thermal diffusivity and the molecular planarity, π–π stacking and crystallinity is demonstrated. High‐performance 2D polymers such as PM6 can possess values comparable to alloys like stainless steel. In BHJs, using a polymeric acceptor can retain high thermal diffusivities compared to fullerene and ITIC acceptors, attributed to the efficient heat transfer within the polymer chains. The results offer not only a simple, highly customizable but sensitive experimental method for thermal transport in OPV systems, but also insights into the phonon dynamics and clinical investigations for thermal stability, pushing forward strategic material design. Thermal stability of organic photovoltaics relies on high thermal diffusivity which indicates promising heatrelief capability. Scanning photothermal deflection serves as a highly sensitive probe for the thermal properties. Phonon transport in semiconducting polymers is found to increase with their planarity and π–π stacking. Using polymeric acceptors in bulk‐heterojunctions can retain efficient heat transfer along the polymer chains.

Magnetic fields, while ubiquitous in many astrophysical environments, are challenging to measure observationally. Based on the properties of anisotropy of eddies in magnetized turbulence, the velocity gradient technique is a method synergistic to dust polarimetry that is capable of tracing plane-of-the-sky magnetic fields, measuring the magnetization of interstellar media and estimating the fraction of gravitational collapsing gas in molecular clouds using spectral line observations. Here, we apply this technique to five low-mass star-forming molecular clouds in the Gould Belt and compare the results to the magnetic field orientation obtained from polarized dust emission. We find that the estimates of magnetic field orientations and magnetization for both methods are statistically similar. We estimate the fraction of collapsing gas in the selected clouds. By using the velocity gradient technique, we also present the plane-of-the-sky magnetic field orientation and magnetization of the Smith Cloud, for which dust polarimetry data are unavailable.The velocity gradient technique is used to measure the magnetic field orientations and magnetization of five low-mass star-forming molecular clouds, also finding that collapsing regions constitute a small fraction of the volume in these clouds.

Turbulence is ubiquitous in the interstellar medium (ISM) and strongly influenced by magnetic fields. Understanding the interaction between magnetized turbulence and the multiphase ISM remains a central question in astrophysics. This thesis addresses these interactions through magnetohydrodynamic (MHD) turbulence theory, numerical simulations, and comparisons with observations. Additionally, We will discuss new two techniques — the Velocity Decomposition Algorithm (VDA) and the Gradient Technique (GT) — to infer turbulent velocity information and probe the magnetic field from the observation. The thesis will also discuss how that strong turbulence stabilizes the Unstable Neutral Medium (UNM), significantly extending its lifetime and increasing its mass fraction. This stabilization impacts the morphology of the Cold Neutral Medium (CNM) via the \"UNM instability\". Utilizing one of the largest multiphase turbulence simulations to date, this work elucidates key observational phenomena, including the Planck-observed E/B asymmetry and the positive TE cross-correlation, demonstrating that these signatures arise naturally from MHD turbulence in polarization maps. Furthermore, we explore turbulence-driven dust-gas dynamics within protoplanetary disks, and new algorithm of conserving magnetic helicity, investigating how dust coagulation influences the formation of planetesimals, and how the conservation of magnetic helicity affect the dynamo process.

The strong alignment of small-scale turbulent Alfvénic motions with the direction of the magnetic field that percolates the small-scale eddies and imprints the direction of the magnetic field is a property that follows from the MHD theory and the theory of turbulent reconnection. The Alfvénic eddies mix magnetic fields perpendicular to the direction of the local magnetic field, and this type of motion is used to trace magnetic fields with the velocity gradient technique (VGT). The other type of turbulent motion, fast modes, induces anisotropies orthogonal to Alfvénic eddies and interferes with the tracing of the magnetic field with the VGT. We report a new effect, i.e., in a magnetically dominated low-\\beta subsonic medium, fast modes are very intermittent, and in a volume, with a small filling factor the fast modes dominate other turbulent motions. We identify these localized regions as the cause of the occasional change of direction of gradients in our synthetic observations. We show that the new technique of measuring the gradients of gradient amplitudes suppresses the contribution from the fast-mode-dominated regions, improving the magnetic field tracing. In addition, we show that the distortion of the gradient measurements by fast modes is also applicable to the synchrotron intensity gradients, but the effect is reduced compared to the VGT.