A century-old tenet in physics and engineering asserts that any type of system, having bandwidth Δω, can interact with a wave over only a constrained time period Δt inversely proportional to the ...bandwidth (Δt·Δω ~ 2π). This law severely limits the generic capabilities of all types of resonant and wave-guiding systems in photonics, cavity quantum electrodynamics and optomechanics, acoustics, continuum mechanics, and atomic and optical physics but is thought to be completely fundamental, arising from basic Fourier reciprocity. We propose that this “fundamental” limit can be overcome in systems where Lorentz reciprocity is broken. As a system becomes more asymmetric in its transport properties, the degree to which the limit can be surpassed becomes greater. By way of example, we theoretically demonstrate how, in an astutely designed magnetized semiconductor heterostructure, the above limit can be exceeded by orders of magnitude by using realistic material parameters. Our findings revise prevailing paradigms for linear, time-invariant resonant systems, challenging the doctrine that high-quality resonances must invariably be narrowband and providing the possibility of developing devices with unprecedentedly high time-bandwidth performance.
Abstract Some typical immune proteins are expressed in the nervous system, among which the paired-immunoglobulin-like receptor B (PirB) is a receptor for major histocompatibility complex class I ...antigen (MHC-I), but may play a physiological role in the brain for neuronal circuitry stability by inhibiting synaptic plasticity. Chronic neuroinflammation is common to many neurodegenerative diseases and is often associated with neuronal/synaptic damage and dysfunction. Here we examined the expression of PirB in the rat brain following intracerebral application of lipopolysaccharide (LPS), which has been shown to induce proinflammatory changes and cognitive deficits in rodents. One month after unilateral intrahippocampal LPS injection (10 μg in 4 μl phosphate-buffered saline, PBS), increased protein levels and immunoreactivity of PirB were detected in the ipsilateral hippocampal formation and cortex of the experimental group relative to vehicle (PBS) control. The increased PirB labeling was localized to astrocytes and neurons. Reduced synaptophysin protein levels and immunoreactivity were also found in the ipsilateral hippocampal formation and cortex in LPS-treated rats relative to controls. Morris water maze tests indicated that hippocampus-dependent spatial learning and memory were impaired in LPS-treated animals. Our findings add new experimental data for an upregulation of immune proteins in neuronal and glial cells in the brain in a model of endotoxin-induced neuroinflammation, synaptic alteration, and cognitive decline. The results suggest that PirB modulation may be involved in the pathological process under neurodegenerative conditions.
•A computational free-surface flow framework for HATTs is presented.•Effect of the free surface on the performance of HATTs is well captured.•Excellent agreement with the experimental data is ...achieved.•Sliding-interface technique is extended to handle the level-set formulation.
A computational free-surface flow framework that enables 3D, time-dependent simulation of horizontal-axis tidal-stream turbines (HATTs) is presented and deployed using a complex-geometry HATT. Free-surface flow simulations using the proposed framework, without any empiricism, are able to accurately capture the effect of the free surface on the hydrodynamic performance of the turbine, as demonstrated through excellent agreement with the experimental data. To carry out the free-surface computations, we have developed a novel level-set redistancing procedure compatible with the sliding-interface technique used for handling the rotor-stator interaction in the HATT full-machine simulations. To illustrate the versatility of the proposed approach, additional computations are carried out where the HATT is subjected to wave action.
•A novel free-surface FSI formulation is proposed.•An efficient computational algorithm for free-surface FSI is outlined.•A numerical wave generation procedure is described.•FSI simulations of ...full-scale floating wind turbine are presented.
In this paper, we propose a computational fluid–structure interaction (FSI) framework for the simulations of the interaction between free-surface flow and floating structures, such as offshore wind turbines. The framework is based on a suitable combination of the finite element method (FEM) and isogeometric analysis (IGA), and has good efficiency, accuracy and robustness characteristics. The free-surface phenomena are modeled using the Navier–Stokes equations of incompressible two-fluid flow in conjunction with the level set method. The FEM-based moving-domain ALE-VMS technique is employed to discretize the fluid mechanics equations, while the IGA-based rotation-free shell and beam/cable formulation is employed to model the mechanics of floating structures. The kinematic and traction compatibility at the fluid–structure interface is handled by means of a recently-developed augmented Lagrangian FSI formulation with formal elimination of the Lagrange multiplier variable. A quasi-direct coupling strategy is adopted to handle the large added mass, and implemented by means of a matrix-free technique. The mathematical formulation of the FSI problem and its algorithmic implementation are described in detail, and two numerical test cases are presented. The first case is a free-surface-flow benchmark example of a solitary wave impacting a fixed, rigid platform. The second case is a set of full-scale free-surface-FSI simulations of the OC3-Hywind floating wind turbine design subjected to wave action. The computational results are compared with experimental and simulation data, with good agreement achieved in all cases where such data was available. Wind-turbine computations in the regime of high-amplitude waves are also presented.
Germline mutations of the breast cancer associated gene 1 (BRCA1) predispose women to breast and ovarian cancers. BRCA1 is a large protein with multiple functional domains and interacts with numerous ...proteins that are involved in many important biological processes/pathways. Mounting evidence indicates that BRCA1 is involved in all phases of the cell cycle and regulates orderly events during cell cycle progression. BRCA1 deficiency, consequently causes abnormalities in the S-phase checkpoint, the G2/M checkpoint, the spindle checkpoint and centrosome duplication. The genetic instability caused by BRCA1 deficiency, however, also triggers cellular responses to DNA damage that blocks cell proliferation and induces apoptosis. Thus BRCA1 mutant cells cannot develop further into full-grown tumors unless this cellular defense is broken. Functional analysis of BRCA1 in cell cycle checkpoints, genome integrity, DNA damage response (DDR) and tumor evolution should benefit our understanding of the mechanisms underlying BRCA1 associated tumorigenesis, as well as the development of therapeutic approaches for this lethal disease.
Hepatocellular carcinoma (HCC) is a highly morbid and prevalent cancer globally. While high quality evidence for mortality benefit of HCC surveillance is lacking, early detection of HCC is likely ...beneficial as prognosis is highly correlated with tumor stage. High risk populations, including patients with cirrhosis and subgroups with Hepatitis B, should undergo surveillance with ultrasound ± alpha-fetoprotein (AFP) at 6-month intervals. In addition, emerging data suggest that patients with Hepatitis C cirrhosis who achieve sustained virologic response should continue surveillance. Further research is needed to determine the value of surveillance in patients with nonalcoholic fatty liver disease in the absence of cirrhosis or with advanced fibrosis of other etiologies. Newer biomarkers and models such as
Lens culinaris
agglutinin-reactive fraction of AFP, des-γ-carboxy prothrombin, and the GALAD score are increasingly utilized in the diagnosis and prognostication of HCC. The role of these biomarkers in surveillance is still under investigation but may potentially offer a more practical alternative to traditional image-based surveillance. Despite recommendations from multiple professional society guidelines, many at-risk patients do not receive HCC surveillance due to barriers at the patient, clinician, and health care system levels. Strategies such as implementing patient navigation services, educating clinicians about surveillance guidelines, and creating automated outreach systems, may improve surveillance rates and ultimately reduce morbidity and mortality from HCC.
One-dimensional quasiperiodic systems with power-law hopping, 1/r^{a}, differ from both the standard Aubry-André (AA) model and from power-law systems with uncorrelated disorder. Whereas in the AA ...model all single-particle states undergo a transition from ergodic to localized at a critical quasidisorder strength, short-range power-law hops with a>1 can result in mobility edges. We find that there is no localization for long-range hops with a≤1, in contrast to the case of uncorrelated disorder. Systems with long-range hops rather present ergodic-to-multifractal edges and a phase transition from ergodic to multifractal (extended but nonergodic) states. Both mobility and ergodic-to-multifractal edges may be clearly revealed in experiments on expansion dynamics.
To establish a machine-learning model based on dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) to differentiate combined hepatocellular–cholangiocarcinoma (cHCC-CC) from ...hepatocellular carcinoma (HCC) before surgery.
Clinical and MRI data of 194 patients with histopathologically diagnosed cHCC-CC (n=52) or HCC (n=142) were analysed retrospectively. ITK-SNAP software was used to delineate three-dimensional (3D) lesions and extract high-throughput features. Feature selection was carried out based on Pearson's correlation coefficient and least absolute shrinkage and selection operator (LASSO) regression analysis. A radiomics model (radiomics features), a clinical model (i.e., clinical-image features), and a fusion model (i.e., radiomics features + clinical-image features) were established using six machine-learning classifiers. The performance of each model in distinguishing between cHCC-CC and HCC was evaluated with the receiver operating characteristic (ROC) curve, the area under the ROC curve (AUC), sensitivity, and specificity.
Significant differences in liver cirrhosis, tumour number, shape, edge, peritumoural enhancement in the arterial phase, and lipid were identified between cHCC-CC and HCC patients (p<0.05). The AUC of the fusion model based on logistic regression was 0.878 (95% CI: 0.766–0.949) in the arterial phase in the test set, and the sensitivity/specificity was 0.844/0.714; however, the AUC of the clinical and radiomics models was 0.759 (95% CI: 0.663–0.861) and 0.838 (95% CI: 0.719–0.921) in the test set, respectively.
The fusion model based on DCE-MRI in the arterial phase can significantly improve the diagnostic rate of cHCC-CC and HCC as compared with conventional approaches.
•The radiomics based on DCE-MRI performs well differentiating cHCC-CC from HCC.•Logistic regression has important value in determining whether cHCC-CC from HCC.•The AUC of the fusion model is 0.878 in differentiating cHCC-CC from HCC.
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