Current options for the treatment of the early-stage HCC conforming to the Milan criteria consist of liver transplantation, hepatic resection (HR), transcatheter arterial chemoembolization (TACE) and ...radiofrequency ablation (RFA) .Whether HR or RFA is the better treatment for early HCC has long been debated. The aim of our paper is to compare the therapeutic effects of radiofrequency ablation (RFA) and hepatic resection (HR) in the treatment of early-stage hepatocellular carcinoma (HCC). Controlled trials evaluating the efficacy between RFA and HR for the treatment of early-stage HCC published before June 2013 were searched electronically using MEDLINE, PubMed, Cochrane Library, and EMBASE databases. Using inclusion and exclusion criteria, two randomized controlled trials and 10 nonrandomized controlled trials were included in the meta- analysis. The results showed that the 3,5-year overall survival rates and 1,3,5 disease-free survival rates were significantly lower after RFA than after HR. However, complications after treatment were less common and the length of hospital stay was significantly shorter after RFA. Additionally, there was no significant difference in the 1-year overall survival rate between RFA and HR. The conclusions of the results show that the difference in the short-term effectiveness of RFA and HR in the treatment of small HCC is not notable, but the long-term efficacy of HR is better than that of RFA. However, HR is associated with more complications and a longer hospital stay.
Magnetic Anomaly Detection (MAD) is a passive method for the detection of ferromagnetic objects. Currently, the performance of a MAD system is limited by the magnetic background noise that is ...non-stationary and shows self-similarity and long-range correlation. In this paper, we propose an empirical mode decomposition (EMD) trend filtering based energy detector for adaptively detecting the magnetic anomaly signal from the background noise. The input data is first detrended adaptively with the energy-ratio trend filtering approach. Then, the magnetic anomaly signal is detected using an energy detector. The proposed detector does not need any a priori knowledge about the target or assumptions regarding the background noise. Experiments also prove that the proposed detector shows a more stable performance than the existing undecimated discrete wavelet transform (UDWT) based energy detector.
Due to the nonlinear and aliasing effects, the sub-Nyquist photonic receiver for radio frequency (RF) signals with large instantaneous bandwidth suffers limited dynamic range and noise performance. ...We designated a deep residual network (Resnet) to realize adaptive linearization across 40 GHz bandwidth. In contrast to conventional linearization methods, the deep learning method achieves the suppression of multifactorial spurious distortions and the noise floor simultaneously. It does not require an accurate calculation of the nonlinear transfer function or prior signal information. The experiments demonstrated that the proposed Resnet could improve the spur-free dynamic range (SFDR) and the signal-to-noise ratio (SNR) significantly by testing with single-tone signals, dual-tone signals, wireless communication signals, and modulated radar signals.
This paper presents a high selectivity frequency selective rasorber (FSR) with an adjustable out-band absorptivity property. This rasorber is composed of a dynamic ...absorptive-frequency-selective-surface (AFSS) on the top, with PIN diodes employed to achieve tunable absorptivity, and a high-quality (Q)-factor bandpass frequency-selective-surface (FSS) in the bottom, with aperture-coupled resonators (ACRs) structure to obtain a high-selectivity transparent window. To begin with, theoretical analyses and extensive simulations are performed to evaluate the performance. Subsequently, a prototype is fabricated and measured, showing a 1 dB transmission window with high selectivity at 8.43-8.51 GHz and electrical tuning on the absorption rate response with a wide tunable span of 0.9 at out bands of 4.43-7.76 GHz and 9.21-13.45 GHz, respectively. The proposed rasorber with dynamic tunability of absorptivity can provide radar cross section (RCS) consistent with the environment, which is potential for radar stealth, deception, and anti-identification.
Evaluating the fire safety of hydrogen storage cylinders is crucial before hydrogen can be widely used in fuel cell vehicle applications. This research presents a comprehensive 3D hydrogen cylinder ...fire safety model that couples ANSYS FLUENT to ANSYS-mechanical and simulates a vehicle-mounted hydrogen cylinder when subjected to fire. By considering a volumetric heat source that is beneath the hydrogen cylinder and by factoring the effects of complex heat transfer (convection, radiation, etc.), fluid dynamics, and the mounting space's solid wall, the temperature distributions across the hydrogen cylinder wall are calculated with greater accuracy than existing models that over-simplify the fire source model. Moreover, the temperature distributions are input to ANSYS Mechanical to calculate the induced mechanical stress. Then, a series of parametric analyses are conducted to evaluate their influence on maximum temperature and mechanical stress. Results reveal that thermal radiation is the dominant heat transfer mechanism from the fire source to the cylinder body. Decreasing the cylinder body's thermal conductivity can reduce maximum mechanical stress by 7%.Meanwhile, increasing the cylinder body thickness introduced more thermal strain to increase the maximum mechanical stress, which is not conducive to improving fire safety.
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•An accurate 3D vehicle-mounted hydrogen cylinder fire simulation is developed.•Heat transfer and fluid dynamics of ANSYS-FLUENT are coupled to ANSYS-mechanical.•A series of parametric analyses are conducted to evaluate thermo-mechanical stress.•Small latent heat transfer meant the top wall had little effect on fire safety.•Mechanical stress can be marginally reduced by thermally insulating the cylinder.
Microwave photonics scanning channelizer with digital image-reject mixing and linearization is investigated by employing a cascaded distributed feedback semiconductor laser (DFB) operating at stable ...locking dynamics when subjected to flat optical frequency comb (OFC) injection. The OFC injection locking (OIL) provides a high-quality coherent optical local oscillator with ultra-broadband tuning capability by demultiplexing and amplifying individual comb from densely spaced OFC. The channelizer receiver scans the whole frequency range at discrete steps through a single tunable heterodyne receiver and a single ADC, thus reducing the SWaP and increasing agility. By introducing the digital Hartley structure image-reject mixing (IRM), the amplitude and phase imbalance of the IQ channel are easily compensated, resulting in a high image rejection ratio (IRR) up to around ∼50 dB for all channels. Furthermore, a novel digital linearization technique is employed to suppress third-order intermodulation components by more than 19.43 dB while improving the spurious free dynamic range (SFDR) by 16.1 dB The analysis confirms the scheme’s capability for detecting signals from 1.5 GHz to 43.5 GHz and beyond with excellent performance. The proposed channelizer can find applications in future wideband RF systems, including 5G and beyond wireless communications, electronic warfare, and radars.
•Microwave photonics scanning channelizer has an ultra-wide frequency range (1.5∼43.5 GHz).•Enhanced spurious free dynamic range and high image-rejection are achieved by digital post-processing.•The scanning mode reduce the SWaP and avoid large spacing OFC.
A novel reconfigurable filter antenna with three ports for three dependent switchable states for impulse radio-ultrawideband (IR-UWB)/wireless local area network (WLAN)/worldwide interoperability for ...microwave access (WiMAX) applications is presented in this paper. Three positive-intrinsic-negative diodes, controlled by direct current, are employed to realize frequency reconfiguration of one ultra-wideband state and two narrowband states (2.4 GHz and 3.5 GHz). The time domain characteristic of the proposed antenna in the ultra-wideband state is studied, because of the features of the IR-UWB system. The time domain analysis shows that the reconfigurable filtering antenna in the wideband state performs similarly to the original UWB antenna. The compact size, low cost, and expanded reconfigurable filtering features make it suitable for IR-UWB systems that are integrated with WLAN/WiMAX communications.
A reconfigurable bandwidth antenna for an impulse radio-UWB (IR/UWB) system design is illustrated in this paper. By adopting a continuously tunable low-pass filter by varactor at the feed of the ...antenna, the proposed antenna obtains a continuous tunable bandwidth from 1.02 GHz to 2.42 GHz. To ensure the identifiability of transmitted pulses in (IR-UWB) system, the antenna is analyzed in both frequency domain and time domain. The proposed antenna is valid with a system fidelity factor (SFF) above 0.8 while the bandwidth is tuning. The compact size, low cost, and tunable bandwidth with the identifiability of the transmitted pulse makes it suitable for UWB impulse radars to improve the utility ratio of frequency, and dynamic adjustment avoids interference of the IR-UWB in other communication frequency bands.
Switchable frequency selective rasorbers (FSRs) have been extensively studied recently due to their out-of-band stealth and in-band electromagnetic wave manipulation abilities. Nevertheless, the vast ...majority of the reported FSRs are incapable of in-band waves control, including simultaneous transmission, reflection, and absorption. Herein, this article proposes a multifunctional switchable FSR that is capable of switching among all three transmission modes at the operation band. This FSR consists of two periodic layers embedded with p-i-n diodes that are separately controlled by bias voltages. By changing the states of the p-i-n diodes in each layer, the incident wave within the operation band can be manipulated continuously (transmission mode in the on-on state, reflection mode in the on-off state, absorption mode in the off-off state). Furthermore, the broad region below the operation band retains high absorptivity throughout all states. The physical properties of the multifunctional switchable FSR are investigated with an equivalent circuit model. The measured results show that a switchable operation frequency is located at 10.15 GHz, and an effective absorption band ranges from 3.8 GHz to 8.6 GHz. The proposed design has promising potential for multiple applications, such as communication for the transmission mode, protection of high-power microwaves for the reflection mode, and stealth and electromagnetic compatibility for the absorption mode.
The endoplasmic reticulum (ER) is an essential organelle for protein synthesis, folding and modification, lipid synthesis, and calcium storage. When endogenous or exogenous stimuli lead to ...ER‑synthesized protein folding dysfunction, numerous unfolded or misfolded proteins accumulate in the ER cavity and cause a series of subsequent responses, referred to as ER stress. If ER stress is continuous, the unfolded protein response (UPR) is not enough to remove the accumulated unfolded and misfolded proteins, and thus, UPR signaling pathways will drive cell apoptosis. Glioblastoma (GBM) is currently the most aggressive and common malignant tumor of the nervous system. Since ER stress may increase the sensitivity of GBM to temozolomide, this article reviews the possible mechanisms of ER stress‑induced apoptosis and the factors affecting ER stress, and evaluates the potential of ER stress as a therapeutic target.
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