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• The field tests were carried out for more than two years on Chinese high-speed railway lines, it is found that the main failure cause of the BBF is the resonant vibration of 8–20 Hz which excites the first-order natural mode of the frame. • It is found that the measured data are quite different from the IEC61373 standard, it is necessary to reassess whether the limits in the standard are safe or not for Chinese high-speed railway lines. • The bolster exhibits obvious non-Gaussian characteristics, it could be inferred that the Gaussian signal maybe not always suitable for the input load spectrum. Aiming to solve the failure problem of welded frame suspended under high-speed EMU, a long-term tracking test was carried out. The modal resonance of 8–20 Hz is the main cause of structural failure. The characteristics of the in-service vibration environment and the difference with the standard load spectrum are analyzed. The measured load spectrum exceeds the IEC61373 standard load spectrum in the frequency range of 10–20 Hz and 30–120 Hz. Meanwhile, the kurtosis of measured acceleration signal does not always follow the Gaussian distribution for the carbody bolsters, and the acceleration and dynamic stress amplitude of the bolster and suspension equipment frame increase more with higher train speed. After a finite element model with welded joints was developed to evaluate the fatigue life, an optimized prototype BBF was designed. The reliability of the optimized structure is verified by rig test. The optimized structure avoids 8–20 Hz resonance and meets the test requirements. [ABSTRACT FROM AUTHOR]

Abstract Underwater acoustic sensor networks play a significant role in ocean observation, pollution monitoring and underwater remote control. Different from conventional sensor networks, transmission efficiency and lifetime for nodes in underwater acoustic sensor networks is vital since it is difficult to change batteries of buoy relays and underwater sensors. In this paper, two resource allocation algorithms for energy harvesting time and transmit power allocation in underwater acoustic sensor networks with single and multiple wireless energy harvesting buoy nodes are proposed to maximize the sum rate and energy efficiency. Both of the circuit power consumption and transmission power consumption are considered as the power consumption of the system. We first propose an optimal algorithm to allocate the time of energy harvesting slot for sum rate maximization. From the derivation, we show that the sum rate of the network grows as the transmission power increases. However, when the transmission power is extremely large, the energy efficiency of the network starts to decrease. Thus a joint algorithm with energy harvesting time and transmit power allocation is further provided for energy efficiency maximization. Simulation results validate the sum rate improvement under our proposed sum rate maximization algorithm and energy efficiency improvement under the proposed energy efficiency maximization algorithm. [ABSTRACT FROM AUTHOR]

Vehicle to everything (V2X) is emerging as a promising application scenario of next generation mobile communications. In V2X systems, a series of applications (information transmission, in-car entertainment, etc.) rely on the limited vehicle battery. However, most prior work limits to the automatic piloting, channel measurement/estimation and high speed transmissions, seldom study has been done on the battery-limited for V2X. In light of this, here we investigate the problem of the downlink beamforming design for signal-to-interference ratio balancing in a V2X-SWIPT environment with imperfectly estimated channels at the base station, where a practical non-linear energy harvesting model is considered. The problem is further transformed into a two-layer optimization problem, where we solve the inner-level problem by exploiting S-Procedure, and the outer-level problem through bisection approach. Finally, simulation results are carried out to confirm that the proposed robust beamforming design obtains a favorable result in applications of practical interest. [ABSTRACT FROM AUTHOR]

In this paper, we present two novel interference management stratagems for coexisting one primary user (PU) and multiple secondary users (SUs) by exploiting the unused spatial directions at PU. The cognitive stations sense their environment to determine the users they are interfering with, and adapt to it by designing the corresponding precoders using interference alignment (IA) in order to avoid causing performance degradation to nearby PU and SUs. The first proposed approach judiciously designs the set of precoders based on an improved version of minimum weighted leakage interference algorithm. However, there are still leftover interference signals in SUs’ desired signal space due to the limited iterative times in the first algorithm. To tackle this problem, another scheme combining the first one and power allocation method at the secondary stations is developed. Numerical results validate the effectiveness of the proposed algorithms. [ABSTRACT FROM AUTHOR]

• We propose the Scale Attention mechanism, which is effective for multi-scale problem in liver tumor segmentation. • We improve the self-attention and propose the Axis Attention mechanism, which is efficient and effective for spatial information modeling globally. • We combine the Scale Attention and the Axis Attention mechanisms organically with a style of adaptive global pooling in SAA-Net, which is efficient for preserving fine-grained information in global pooling, beneficial to final segmentation. In liver tumor segmentation tasks, the problems of multi-scale and global spatial modeling significantly affect the segmentation accuracy. For multi-scale feature extraction, we propose a dynamic scale attention mechanism, which assigns adaptive weights to multi-scale convolutions. Scale Attention could fuse receptive fields from multiple scales, which is beneficial to segmentation of multi-scale targets. For global modeling of spatial information, Axis Attention is proposed, which optimizes the computational resources utilization of self-attention and the attentive effect of convolution attention simultaneously. Axis Attention could model spatial long-range dependencies effectively and efficiently. Scale Attention and Axis Attention are organically combined with a style of adaptive global pooling and the composite proposed mechanism is called Scale-Axis-Attention (SAA). We incorporate it into U-shaped network to improve the performance of liver tumor segmentation, termed as SAA-Net. Our method not only is far superior to self-attention in terms of the computational resources utilization, but also incorporates the scale and spatial attention mechanisms simultaneously for performance improvement. We show that SAA-Net achieves the improved model capability and generalization performance through extensive experiments on qualitative and quantitative test datasets. Experiments also demonstrate the effectiveness of our method in the segmentation of tumors with small size. [ABSTRACT FROM AUTHOR]

In this paper, a blockchain-enabled relay-aided wireless network for sustainable e-agriculture is investigated, where best relay selection scheme based on the maximization of equivalent signal to noise ratio/signal to interference ratio (SNR/SIR) is considered. The performance of best relay selection under α − μ channel are derived in the paper, where closed-form expressions for transmission successful rate (TSR) and overall communication throughput (OCT) with and without interference are obtained. From derivation results, as the number of potential relay nodes increase, TSR and OCT performance will be ameliorated correspondingly. Numerical simulations have been performed to validate the correctness of our derivations. [ABSTRACT FROM AUTHOR]

Wireless energy transmission is considered in the Internet-of-Things (IoT) dual-hop communication systems. The power splitting method is employed at the relay node to receive the wireless energy and the wireless information simultaneously from the source to the relay node in the first resource block. With the harvested energy at the relay node, one wireless information node and one wireless energy harvest node are served simultaneously by the relay node in the second resource block. The optimization problem is formulated to maximize the energy efficiency defined as the ratio of the wireless information throughput of the first destination node over the power consumed by the whole IoT systems, which is subject to the required minimum energy harvested at the second destination node of the energy transfer. To tackle the non-convex problem, the exact expression of the wireless information throughput is approximated by the high signal to noise ratio (SNR) approximation method, which is shown very tight to the exact expression. Hence, the asymptotically optimal solution is derived in analytical expression by employing the Lagrangian method. Numerical simulations verify the performance of the proposed scheme. [ABSTRACT FROM AUTHOR]

Abstract: The TiB2-contained composite Fe–B–C coatings are deposited by the plasma transferred-arc (PTA) powder surfacing process. The coating''s thermal ability, arc ablation resistance and wear resistance at high temperature were analyzed. It is concluded that TiB2-contained composite Fe–B–C coating having excellent wear resistance at 600 °C and tempering resistance at 900 °C. Furthermore, this coating can effectively resist the arc ablation (120 A arc currents) within 7 s. [Copyright &y& Elsevier]

Aims: The aim of this conventional case-control study was to investigate the prevalence and relationship between Helicobacter pylori infection in type 2 diabetes mellitus (DM) and diabetic nephropathy (DN).Methods: A total of 241 type 2 DM patients and 69 non-diabetic subjects with dyspeptic symptoms were enrolled in the study. Gastroduodenal lesions were observed by gastrointestinal endoscopy and the presence of H. pylori was identified by rapid urease test and serum IgG antibodies to H. pylori. According to the urinary albumin excretion rate (UAE), patients were classified into diabetes mellitus group (DM group, with UAE <30 mg/24h); diabetic nephropathy group 1 (DN group 1, with UAE 30 mg/24 h to <300 mg/24 h); and diabetic nephropathy group 2 (DN group 2 ≥ 300 mg/24 h). The 69 non-diabetic subjects were used as control group. The serum levels of inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-8 were determined using ELISA.Results: The prevalence of H. pylori infection in DN group 1 and DN group 2 was 45/72 (62.5%) and 34/53 (64.15%), respectively, which was significantly higher than in control [28/65 (43.1%)] and DM groups [42.9% (27/63)]. No significant differences of H. pylori prevalence were detected between DN groups as well as DM and control groups. Interestingly, in both DN groups, higher levels of IL-8, TNF-α and urinary albumin excretion rate were found in H. pylori positive subjects.Conclusions: Diabetic nephropathy patients are more susceptible to H. pylori infection. Our data support an association between H. pylori infection and diabetic nephropathy. [ABSTRACT FROM AUTHOR]

• miR-200c overexpression upregulated PAI-2 in TNBC. • miR-200c/PAI-2 increased macrophages. • miR-200c/PAI-2 promotes the progression of TNBC by inducing macrophage polarization. To investigate the effect of miR-200c/PAI-2 on macrophage polarization into M2-type TAMs in TNBC. PAI-2 expression in MDA-MB-231con, MDA-MB-231miR-200ab and MDA-MB-231miR-200c breast cancer cells was evaluated by RT-PCR and immunofluorescence (IF), while the expression of the TAM marker F4/80 and the M2-type TAM marker CD206 in MDA-MB-231con, MDA-MB-231miR-200c and MDA-MB-231miR-200c/siPAI-2 mouse lung metastatic tumor tissues was examined with immunohistochemistry (IHC). The effects of RAW264.7 cells on MDA-MB-231con, MDA-MB-231miR-200c and MDA-MB-231miR-200c/siPAI-2 were examined by transwell co-culture. CD206 expression in RAW264.7 cells were confirmed by immunostaining. The level of PAI-2 and IL-10 in the co-culture supernatants were assessed using ELISA. 1. RT-PCR and IF analysis showed that PAI-2 was upregulated in MDA-MB-231miR-200c cells. 2. IHC assays analysis showed that the numbers of F4/80 and CD206 positive cells were increased in MDA-MB-231miR-200c tumor tissues, while in MDA-MB-231miR-200c/siPAI-2 tumor tissues were decreased. 3. Transwell co-culture assays analysis showed that MDA-MB-231miR-200c cells significantly promoted the cell migration ability compared with the control group, while knockdown PAI-2 significantly inhibited the cell migration ability (P < 0.05). 4. Transwell co-culture and immunostaining assays analysis showed that overexpression miR-200c in MDA-MB-231 cell line increased the CD206 expression in RAW264.7 cells, while knockdown PAI-2 decreased. 5. ELISA assays analysis showed that miR-200c-mediated MDA-MB-231 cells significantly increased the secretion of PAI-2 and IL-10, while decreased the secretion of PAI-2 and IL-10 in MDA-MB-231 miR-200c/siPAI-2 cells. miR-200c promotes the malignant progressions of TNBC by PAI-2 upregulation and M2 phenotype macrophages polarization. [ABSTRACT FROM AUTHOR]