Sixth-generation (6G) wireless networks are envisioned to provide global coverage for the intelligent digital society of the near future, ranging from traditional terrestrial to non-terrestri-al ...networks, where reliable communications in high-mobility scenarios at high carrier frequencies would play a vital role. In such scenarios, the conventional orthogonal frequency division multiplexing (OFDM) modulation, that has been widely used in both the fourth-generation (4G) and the emerging fifth-generation (5G) cellular systems as well as in WiFi networks, is vulnerable to severe Doppler spread. In this context, this article aims to introduce a recently proposed two-dimension-al modulation scheme referred to as orthogonal time-frequency space (OTFS) modulation, which conveniently accommodates the channel dynamics via modulating information in the delay-Doppler domain. This article provides an easy-reading overview of OTFS, highlighting its underlying motivation and specific features. The critical challenges of OTFS and our preliminary results are presented. We also discuss a range of promising research opportunities and potential applications of OTFS in 6G wireless networks.
Localization and synchronization are very important in many wireless applications such as monitoring and vehicle tracking. Utilizing the same time of arrival (TOA) measurements for simultaneous ...localization and synchronization is challenging. In this paper, we present a factor graph (FG) representation of the joint localization and time synchronization problem based on TOA measurements, in which the non-line-of-sight (NLOS) measurements are also taken into consideration. On this FG, belief propagation (BP) message passing and variational message passing (VMP) are applied to derive two fully distributed cooperative algorithms with low computational requirements. Due to the nonlinearity in the observation function, it is intractable to compute the messages in closed form, and most existing solutions rely on Monte Carlo methods, e.g., particle filtering. We linearize a specific nonlinear term in the expressions of messages, which enables us to use a Gaussian representation for all messages. Accordingly, only the mean and variance have to be updated and transmitted between neighboring nodes, which significantly reduces the communication overhead and computational complexity. A message passing schedule scheme is proposed to trade off between estimation performance and communication overhead. Simulation results show that the proposed algorithms perform very close to particle-based methods with much lower complexity, particularly in densely connected networks.
The rapid development of mobile communications requires even higher spectral efficiency. Non-orthogonal multiple access (NOMA) has emerged as a promising technology to further increase the access ...efficiency of wireless networks. Among several NOMA schemes, it has been shown that sparse code multiple access (SCMA) is able to achieve better performance. In this paper, we consider a downlink MIMO-SCMA system over frequency selective fading channels. For optimal detection, the complexity increases exponentially with the product of the number of users, the number of antennas and the channel length. To tackle this challenge, we propose near optimal low-complexity iterative receivers based on factor graph. By introducing auxiliary variables, a stretched factor graph is constructed and a hybrid belief propagation (BP) and expectation propagation (EP) receiver, named stretch-BP-EP, is proposed. Considering the convergence problem of BP algorithm on loopy factor graph, we convexify the Bethe free energy and propose a convergence-guaranteed BP-EP receiver, named conv-BP-EP. We further consider cooperative network and propose two distributed cooperative detection schemes to exploit the diversity gain, namely, belief consensus-based algorithm and the Bregman alternative direction method of multipliers (ADMM)-based method. Simulation results verify the superior performance of the proposed conv-BP-EP receiver compared with other methods. The two proposed distributed cooperative detection schemes can improve the bit error rate performance by exploiting the diversity gain. Moreover, Bregman ADMM method outperforms the belief consensus-based algorithm in noisy inter-user links.
Let
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=
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t
∈
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be a centered space-time anisotropic Gaussian random field in
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with stationary increments, where the components
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(
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1
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are independent but distributed ...differently. Under certain conditions, we not only give the Hausdorff dimension of the graph sets of
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in the asymmetric metric in the recurrent case, but also determine the exact Hausdorff measure functions of the graph sets of
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in the transient and recurrent cases, respectively. Moreover, we establish a uniform Hausdorff dimension result for the image sets of
X
. Our results extend the corresponding results on fractional Brownian motion and space or time anisotropic Gaussian random fields.
Yes‐associated protein (YAP) is a transcriptional coactivator that promotes cell proliferation, stem cell maintenance and tissue homeostasis. The YAP activity is primarily regulated through an ...inhibitory phosphorylation by the serine/threonine kinases of Hippo pathway. Here, we show that receptor tyrosine kinase (RTK) erythropoietin‐producing hepatocellular receptor A2 (EphA2) interacts with and phosphorylates YAP protein, leading to stabilization, nuclear translocation and activation of YAP in gastric cancer (GC) cells. EphA2 induces chemotherapy‐resistance by increasing YAP stability and nuclear YAP protein. Knockdown of YAP blocks EphA2‐induced tumor growth in GC xenograft mouse models. Importantly, the coactivation of EphA2 and YAP is manifested in clinical human GC, and is related to GC recurrence. Thus, our results establish a novel EphA2‐to‐YAP pathway that drives GC growth, progression and therapy‐resistance, targeting this pathway would be an efficient way for the treatment of GC, particularly chemotherapy‐resistant GC.
What's new?
The discovery of novel molecular targets is fundamental to the continued advance of therapeutic agents for gastric cancer (GC). In this study, the authors identify a pathway involving interaction between EphA2, a member of the erythropoietin‐producing hepatocellular receptor family, and yes‐associated protein (YAP) as a promising therapeutic target for GC. In GC cells, EphA2 phosphorylation of YAP protein resulted in YAP stabilization, translocation to the nucleus, and activation. Increased YAP stabilization and nuclear concentration in GC cells and mouse models was further associated with EphA2‐induced chemoresistance. In patients, EphA2 overexpression and nuclear YAP accumulation was related to GC relapse.
Abstract In this study, We aim to explore the association between the neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), systemic immune-inflammatory index (SII), lymphocyte to ...monocyte ratio (LMR) and prognostic nutritional index (PNI) and distant metastasis of gastric cancer and develop an efficient nomogram for screening patients with distant metastasis. A total of 1281 inpatients with gastric cancer were enrolled and divided into the training and validation set.Univariate, Lasso regression and Multivariate Logistic Regression Analysis was used to identify the risk factors of distant metastasis. The independent predictive factors were then enrolled in the nomogram model. The nomogram’s predictive perform and clinical practicality was evaluated by receiver operating characteristics (ROC) curves, calibration curves and decision curve analysis. Multivariate Logistic Regression Analysis identified d -dimer, CA199, CA125, NLR and PNI as independent predictive factors. The area under the curve of our nomogram based on these factors was 0.838 in the training cohort and 0.811 in the validation cohort. The calibration plots and decision curves demonstrated the nomogram’s good predictive performance and clinical practicality in both training and validation cohort. Therefore,our nomogram could be an important tool for clinicians in screening gastric cancer patients with distant metastasis.
This investigation was performed to verify whether lncRNA CRNDE sponging miR-181a-5p was involved with sepsis-relevant inflammatory dysfunctions. Aggregately 136 sepsis patients and 151 healthy ...people were recruited, and their fasting peripheral blood was gathered to detect expressions of CRNDE and miR-181a-5p. In addition, THP-1 cells were transfected with si-CRNDE, miR-181a-5p mimic, pcDNA3.1-TLR4 and si-TLR4, and then sepsis-specific inflammatory cytokines within the cells were quantified. The sponging relationships between CRNDE and miR-181a-5p, as well as between miR-181a-5p and TLR4, were ascertained by means of luciferase reporter gene assay. The experimental results revealed that over-expressed CRNDE and under-expressed miR-181a-5p were associated with shortened lifespan of sepsis patients. Mechanically, si-CRNDE-1 and miR-181a-5p mimic were able to reverse the promoting effects of LPS on production of NF-kB, TNF-α, IL-1β and IL-6 by THP-1 cells. Moreover, the expressional change of miR-181a-5p in THP-1 cells was in part owing to its being sponged by CRNDE. Lastly, TLR4, subjected to targeted modification of miR-181a-5p, was capable of disturbing the contribution of CRNDE and miR-181a-5p to THP-1 cells’ release of NF-kB, TNF-α, IL-1β and IL-6. Collectively, the CRNDE/miR-181a-5p/TLR4 axis seemed to have potential in modifying sepsis-related inflammatory pathogenesis, which offered a direction for sepsis diagnosis and treatment.
Autophagy-related gene-5 (ATG-5) is one of the key regulators of autophagic cell death. It has been widely regarded as a protective molecular mechanism for tumor cells during the course of ...chemotherapy. In the present study, we investigated the expression pattern of ATG-5 and multidrug resistance-associated protein-1 (MRP-1) in 135 gastric cancers (GC) patients who were treated with epirubicin, cisplatin and 5-FU adjuvant chemotherapy (ECF) following surgical resection and explored their potential clinical significance. We found that both ATG-5 (77.78%) and MRP-1 (79.26%) were highly expressed in GC patients. ATG-5 expression was significantly associated with depth of wall invasion, TNM stages and distant metastasis of GC (P<0.05), whereas MRP-1 expression was significantly linked with tumor size, depth of wall invasion, lymph node metastasis, TNM stages and differentiation status (P<0.05). ATG-5 expression was positively correlated with MRP-1 (rp = 0.616, P<0.01). Increased expression of ATG-5 and MPR-1 was significantly correlated with poor overall survival (OS; P<0.01) and disease free survival (DFS; P<0.01) of our GC cohort. Furthermore, we demonstrated that ATG-5 was involved in drug resistant of GC cells, which was mainly through regulating autophagy. Our data suggest that upregulated expression of ATG-5, an important molecular feature of protective autophagy, is associated with chemoresistance in GC. Expression of ATG-5 and MRP-1 may be independent prognostic markers for GC treatment.
This work deals with frequency-domain equalization for faster-than-Nyquist (FTN) signaling in doubly selective channels (DSCs). To handle the interference of frequency-domain symbols, the minimum ...mean square error (MMSE) equalizer involves high complexity in DSCs. To overcome the problem, we propose low-complexity receivers based on two variational methods, i.e., mean field (MF) and Bethe approximations. Compared with the MF method, the Bethe approximation takes into account the conditional dependencies of pairwise symbols. By only considering a small set of the frequency-domain symbols that have strong interference to each other, the complexity of the proposed algorithms increases linearly with the block length. Simulation results demonstrate that the proposed algorithms for FTN signaling are able to perform close to the MMSE equalizer in DSCs while with significantly reduced computational complexity.
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