Adult split liver transplantation to treat liver cancer: a single-center retrospective study

BACKGROUND: The increasing morbidity of liver cancer has led to a growing demand for transplantation. Split liver transplantation(SLT) is a promising way to ameliorate organ shortages. However, the safety and efficacy of SLT are still controversial. The aim of this study was to assess the clinical outcome of SLT in liver cancer patients at our center. METHODS: A total of 74 patients who received liver transplantation at a tertiary hospital from March 2019 to July 2023 were retrospectively studied, of whom 37 recipients underwent SLT and 37 recipients underwent whole-graft liver transplantation(WGLT). Clinical data were analyzed and compared between patients who underwent SLT and WGLT.RESULTS: SLT and WGLT were successfully performed, with no intraoperative transplantrelated mortality. Postoperatively, no significant differences in total bilirubin(TB, P=0.266), alanine transaminase(ALT, P=0.403) and aspartate transaminase(AST, P=0.160) levels within 30 d were detected between the two groups. The transplant-related mortality rates were 8.1% in the SLT group and 5.4% in the WGLT group within 30 d of surgery(P=1.000), and 10.8% and 8.1%, respectively, at 90 d after surgery(P=1.000). There were no significant differences in overall survival(OS) and progress-free survival(PFS) between the SLT and WGLT groups(P=0.910, P=0.190). CONCLUSION: Our results show that SLT does not imply additional risks in treating liver cancer compared with WGLT.

Comparative transcriptome analysis between rhesus macaques(Macaca mulatta) and crab-eating macaques(M. fascicularis)

Understanding gene expression variations between species is pivotal for deciphering the evolutionary diversity in phenotypes. Rhesus macaques(Macaca mulatta, MMU)and crab-eating macaques(M. fascicularis, MFA) serve as crucial nonhuman primate biomedical models with different phenotypes. To date, however, large-scale comparative transcriptome research between these two species has not yet been fully explored. Here, we conducted systematic comparisons utilizing newly sequenced RNA-seq data from84 samples(41 MFA samples and 43 MMU samples)encompassing 14 common tissues. Our findings revealed a small fraction of genes(3.7%) with differential expression between the two species, as well as 36.5% of genes with tissue-specific expression in both macaques. Comparison of gene expression between macaques and humans indicated that 22.6% of orthologous genes displayed differential expression in at least two tissues. Moreover,19.41% of genes that overlapped with macaque-specific structural variants showed differential expression between humans and macaques. Of these, the FAM220A gene exhibited elevated expression in humans compared to macaques due to lineage-specific duplication. In summary,this study presents a large-scale transcriptomic comparison between MMU and MFA and between macaques and humans. The discovery of gene expression variations not only enhances the biomedical utility of macaque models but also contributes to the wider field of primate genomics.

Effects of thawing-induced softening on fracture behaviors of frozen rock

Due to the presence of ice and unfrozen water in pores of frozen rock,the rock fracture behaviors are susceptible to temperature.In this study,the potential thawing-induced softening effects on the fracture behaviors of frozen rock is evaluated by testing the tension fracture toughness(KIC)of frozen rock at different temperatures(i.e.-20℃,-15℃,-12℃,-10℃,-8℃,-6℃,-4℃,-2℃,and 0℃).Acoustic emission(AE)and digital image correlation(DIC)methods are utilized to analyze the microcrack propagation during fracturing.The melting of pore ice is measured using nuclear magnetic resonance(NMR)method.The results indicate that:(1)The KIC of frozen rock decreases moderately between-20℃ and-4℃,and rapidly between-4℃ and 0℃.(2)At-20℃ to-4℃,the fracturing process,deduced from the DIC results at the notch tip,exhibits three stages:elastic deformation,microcrack propagation and microcrack coalescence.However,at-4℃e0℃,only the latter two stages are observed.(3)At-4℃e0℃,the AE activities during fracturing are less than that at-20℃ to-4℃,while more small events are reported.(4)The NMR results demonstrate a reverse variation trend in pore ice content with increasing temperature,that is,a moderate decrease is followed by a sharp decrease and-4℃ is exactly the critical temperature.Next,we interpret the thawing-induced softening effect by linking the evolution in microscopic structure of frozen rock with its macroscopic fracture behaviors as follow:from-20℃ to-4℃,the thickening of the unfrozen water film diminishes the cementation strength between ice and rock skeleton,leading to the decrease in fracture parameters.From-4℃ to 0℃,the cementation effect of ice almost vanishes,and the filling effect of pore ice is reduced significantly,which facilitates microcrack propagation and thus the easier fracture of frozen rocks.

Tetrahedral framework nucleic acids/hyaluronic acidmethacrylic anhydride hybrid hydrogel with antimicrobial and anti-inflammatory properties for infected wound healing

Bacterial resistance and excessive inflammation are common issues that hinder wound healing.Antimicrobial peptides(AMPs)offer a promising and versatile antibacterial option compared to traditional antibiotics,with additional anti-inflammatory properties.However,the applications of AMPs are limited by their antimicrobial effects and stability against bacterial degradation.TFNAs are regarded as a promising drug delivery platform that could enhance the antibacterial properties and stability of nanodrugs.Therefore,in this study,a composite hydrogel(HAMA/t-GL13K)was prepared via the photocross-linking method,in which tFNAs carry GL13K.The hydrogel was injectable,biocompatible,and could be instantly photocured.It exhibited broad-spectrum antibacterial and anti-inflammatory properties by inhibiting the expression of inflammatory factors and scavenging ROS.Thereby,the hydrogel inhibited bacterial infection,shortened the wound healing time of skin defects in infected skin full-thickness defect wound models and reduced scarring.The constructed HAMA/tFNA-AMPs hydrogels exhibit the potential for clinical use in treating microbial infections and promoting wound healing.

Generation of mitochondrial replacement monkeys by female pronucleus transfer

Mutations in mitochondrial DNA(mtDNA)are maternally inherited and have the potential to cause severe disorders.Mitochondrial replacement therapies,including spindle,polar body,and pronuclear transfers,are promising strategies for preventing the hereditary transmission of mtDNA diseases.While pronuclear transfer has been used to generate mitochondrial replacement mouse models and human embryos,its application in non-human primates has not been previously reported.In this study,we successfully generated four healthy cynomolgus monkeys(Macaca fascicularis)via female pronuclear transfer.These individuals all survived for more than two years and exhibited minimal mtDNA carryover(3.8%–6.7%),as well as relatively stable mtDNA heteroplasmy dynamics during development.The successful establishment of this nonhuman primate model highlights the considerable potential of pronuclear transfer in reducing the risk of inherited mtDNA diseases and provides a valuable preclinical research model for advancing mitochondrial replacement therapies in humans.

Rapid hydrate formation and efficient gas separation based on aqueous solid carrier

The long hydrate induction time and limited gas-liquid contact area leads to slow hydrate formation rate and low water-hydrate conversion rate.Porous media are often used to promote hydrate formation because of their large specific surface area.Consequently,we used 3A molecular sieve as a water-carrying solid in this work,and investigated the dynamic renewal of the gas-liquid interface and its effect on hydrate formation.The formation kinetics of ethane hydrate was first measured in an aqueous molecular sieve system.Then the separation of(H_(2)+CH_(4)+C_(2)H_(6)+C_(3)H_(8))gas mixture was conducted via hydrate formation.The results show that the formation rate and gas storage capacity of ethane hydrate can be greatly improved by using aqueous molecular sieve.Compared with a pure water system under the same temperature and pressure,aqueous molecular sieve has obvious advantages in separation effect and energy consumption for separating gas mixtures.

The immunomodulatory effects and mechanisms of magnesium-containing implants in bone regeneration:A review

Traditional designs and developments of bone biomaterials mostly concentrate on the positive regulation of osteoblast lineage cells,but often ignore the importance of immune responses and the equilibrium between bone resorption mediated by osteoclasts and bone formation mediated by osteoblasts.Immune dysregulation is associated with an imbalance between pro-inflammatory and anti-inflammatory processes,which may influence the efficacy of bone therapy.Therefore,implanted biomaterials should appropriately and precisely modulate subsequent immune responses.Magnesium(Mg)has been used to fabricate various Mg alloys for bone repair because of its favorable attributes such as osteogenic potential,immune regulation characteristics,biodegradability,and biocompatibility.Various basic research and clinical trials have been already conducted in many countries to explore the physical properties of Mg-containing implants and their clinical outcomes in bone fracture and defect repair.Therefore,this review summarizes the immune response to Mg-containing implants,and further organizes the current research and development progress of Mg-containing implants.The review aims to offer an overview of the current knowledge on immunomodulation of Mg-containing implants and future challenges in their clinical application,which could provide further insight in the development of better strategies for the treatment of bone defect and fracture.

Analysis of pressure response at an observation well against pressure build-up by early stage of CO_(2)geological storage project

To ensure a safe and stable CO_(2)storage,pressure responses at an observation well are expected to be an important and useful field monitoring item to estimate the CO_(2)storage behaviors and the aquifer parameters during and after injecting CO_(2),because it can detect whether the injected CO_(2)leaks to the ground surface or the bottom of the sea.In this study,pressure responses were simulated to present design factors such as well location and pressure transmitter of the observation well.Numerical simulations on the pressure response and the time-delay from pressure build-up after CO_(2)injection were conducted by considering aquifer parameters and distance from the CO_(2)injection well to an observation well.The measurement resolution of a pressure transmitter installed in the observation well was presented based on numerical simulation results of the pressure response against pressure build-up at the injection well and CO_(2)plume front propagations.Furthermore,the pressure response at an observation well was estimated by comparing the numerical simulation results with the curve of CO_(2)saturation and relative permeability.It was also suggested that the analytical solution can be used for the analysis of the pressure response tendency using pressure build-up and dimensionless parameters of hydraulic diffusivity.Thus,a criterion was established for selecting a pressure transducer installed at an observation well to monitor the pressure responses with sufficient accuracy and resolution,considering the distance from the injection well and the pressure build-up at the injection well,for future carbon capture and storage(CCS)projects.

Research progress on the anti-colorectal cancer effect of traditional Chinese medicine active ingredients based on ferroptosis

Ferroptosis is defined as an iron-dependent form of regulated cell death that is initiated by the toxic accumulation of lipid peroxides on cellular membranes.In the past decade,ferroptosis has aroused considerable interest in comprehensive treatment of colorectal cancer,mainly as it is a specific cell death mode that is mechanistically and morphologically differ from other forms of cell death such as autophagy,apoptosis,and pyroptosis,following by holding a giant potential for the therapy of colorectal cancer.Research has found that various active ingredients in traditional Chinese medicine possess the ability of inducing ferroptosis in colorectal cancer cells through pathways such as lipid metabolism,iron metabolism,or cysteine/glutamate transporter system,which demonstrating enormous clinical therapeutic potential.In this review,the metabolic regulatory network of ferroptosis is introduced from the perspective of ferroptosis mechanism,and the information on the induction of ferroptosis in colorectal cancer cells by active ingredients of traditional Chinese medicine is also be retrospected,which the purpose is to provide novel strategies for the anti-colorectal cancer therapy of active ingredients in traditional Chinese medicine.

利用Ka波段云雷达对青藏高原三类重要天气系统云宏观参数日变化特征的研究

青藏高原上空云宏观参数的日变化受大尺度环流、当地太阳辐射和地表过程的联合作用,对辐射收支、辐射传输及感热、潜热的分布等有重要影响。由于缺乏持续定量的观测,对各类天气系统云宏观参数日变化特征的了解还十分不足。多波段多大气成分主被动综合探测系统APSOS(Atmospheric Profiling Synthetic Observation System)的Ka波段云雷达是首部在青藏高原实现长期观测云的雷达。本文基于2019年全年APSOS的Ka波段云雷达资料,采用统计和快速傅里叶变换方法研究了西风槽、切变线和低涡三类重要天气系统影响下的有云频率、单层非降水云或者降水云非降水时段的云顶高度、云底高度和云厚日变化的时域和频域特征,得到了统计回归方程。主要结论有:(1)西风槽系统日均有云频率为56.9%,切变线系统为50.8%,低涡系统达73%。(2)尽管西风槽和切变线系统的成因不同,但两类系统云宏观参数的日变化趋势和主要谐波周期相似:日变化趋势基本为单峰单谷型,日出前最低,日落前最高。有云频率表现为日变化和半日变化,单层云云顶高度、云底高度和云厚主要表现为日变化。(3)低涡系统云宏观参数的日变化特征与前两类系统明显不同:日变化趋势表现为多峰多谷型,虽然有云频率和单层云云顶高度、云底高度主要谐波中均以日变化振幅最大,但频谱分布分散,云厚主要变化中振幅最大的是周期为4.8 h的波动。(4)得到了各系统有云频率、单层云云顶高度、云底高度和云厚日变化的统计回归方程。

基于超润湿材料的乳液油水分离研究进展

在表面活性剂的作用下,油水混合物易转变为乳液,从而形成稳定的油水混合系统,给分离带来了困难。结合固体表面微观几何结构和化学组成,制备的超润湿材料为乳液油水分离提供了一个良好的平台。文中首先介绍了超润湿性的基本理论,然后综述了基于超润湿材料的乳液分离研究进展,包括分离油包水乳液的超疏水超亲油材料、处理水包油乳液的超亲水及水下超疏油材料和同时分离两种类型乳液的智能超润湿材料。最后,对该领域存在的一些问题以及未来的发展方向分别进行了总结和展望。

Changes in the thermodynamic properties of alkaline granite after cyclic quenching following high temperature action

During the development of hot dry rock,the research on thermal fatigue damage caused by thermal shock of cold and heat cycles is the basis that ensures the long-term utilization of geothermal resources,but there are not enough relevant studies at present.Based on this,the thermal damage tests of granite at different temperatures(250,350,450°C)and quenching cycles(1,5,10,15 cycles)were carried out.Preliminary reveals the damage mechanism and heat transfer law of the quenching cycle effect on hot dry rock.The results show that with the increase of temperature and cycles,the uneven thermal expansion of minerals and the thermal shock caused by quenching promote the crack development of granite,resulting in the decrease of P-wave velocity,thermal conductivity and uniaxial compressive strength of granite.Meanwhile,the COMSOL was used to simulate the heat transfer of hot dry rock under different heat treatment conditions.It concluded that the increase in the number of quenching cycles reduced the heat transfer capacity of the granite,especially more than 10 quenching cycles,which also reflects that the thermal fatigue damage leads to a longer time for the temperature recovery of the hot dry rock mass.In addition,the three-dimensional nonlinear fitting relationship among thermal conductivity,temperature and cycle number was established for the first time,which can better reveal the change rule of thermal conductivity after quenching thermal fatigue effect of hot dry rock.The research results provide theoretical support for hot dry rock reservoir reconstruction and production efficiency evaluation.

Inconsistency of changes in uniaxial compressive strength and P-wave velocity of sandstone after temperature treatments

It is generally accepted that the uniaxial compressive strength(UCS)and P-wave velocity of rocks tend to decrease simultaneously with increasing temperature.However,based on a great number of statistical data and systematic analysis of the microstructure variation of rocks with temperature rising and corresponding propagation mechanism of elastic wave,the results show that(1)There are three different trends for the changes of UCS and P-wave velocity of sandstone when heated from room temperature(20C or 25C)to 800C:(i)Both the UCS and P-wave velocity decrease simultaneously;(ii)The UCS increases initially and then decreases,while the P-wave velocity decreases continuously;and(iii)The UCS increases initially and then fluctuates,while the P-wave velocity continuously decreases.(2)The UCS changes at room temperaturee400C,400Ce600C,and 600Ce800C are mainly attributed to the discrepancy of microstructure characteristics and quartz content,the transformation plasticity of clay minerals,and the balance between the thermal cementation and thermal damage,respectively.(3)The inconsistency in the trends of UCS and P-wave velocity changes is caused by the change of quartz content,phase transition of water and certain minerals.

Application of Neural Network in Fault Location of Optical Transport Network

Due to the increasing variety of information and services carried by optical networks, the survivability of network becomes an important problem in current research. The fault location of OTN is of great significance for studying the survivability of optical networks. Firstly, a three-channel network model is established and analyzing common alarm data, the fault monitoring points and common fault points are carried out. The artificial neural network is introduced into the fault location field of OTN and it is used to judge whether the possible fault point exists or not. But one of the obvious limitations of general neural networks is that they receive a fixedsize vector as input and produce a fixed-size vector as the output. Not only that, these models is even fixed for mapping operations (for example, the number of layers in the model). The difference between the recurrent neural network and general neural networks is that it can operate on the sequence. In spite of the fact that the gradient disappears and the gradient explodes still exist in the neural network, the method of gradient shearing or weight regularization is adopted to solve this problem, and choose the LSTM (long-short term memory networks) to locate the fault. The output uses the concept of membership degree of fuzzy theory to express the possible fault point with the probability from 0 to 1. Priority is given to the treatment of fault points with high probability. The concept of F-Measure is also introduced, and the positioning effect is measured by using location time, MSE and F-Measure. The experiment shows that both LSTM and BP neural network can locate the fault of optical transport network well, but the overall effect of LSTM is better. The localization time of LSTM is shorter than that of BP neural network, and the F1-score of LSTM can reach 0.961566888396156 after 45 iterations, which meets the accuracy and real-time requirements of fault location. Therefore, it has good application prospect and practical value to introduce neural network into the fault location field of optical transport network.

Pure Mucinous Carcinoma of the Breast:a Clinicopathologic Analysis with 56 Patients

Objective To assess recent trends and prognostic features in the treatment of pure mucinous carcinoma(PMC) of the breast.Methods Fifty-six patients diagnosed with PMC of the breast in our hospital from December 1982 to June 2008 were included.We evaluated the general information and tumor characteristics of the patients,examined the relationship between these factors and prognosis.Fisher's exact test was applied to analyze tumor characteristics.Results The mean age of the patients was 53.7 years.The majority of the patients presented with early stage disease.Tumor size was found not a significant prognostic factor in this study.Mean follow-up period was 39 months and no breast cancer-related deaths were identified in the patient cohort.Conclusions PMC of the breast has a favorable prognosis.Tumor size does not appear to significantly impact survival.

New insights into insulin: The anti-inflammatory effect and its clinical relevance

Hyperglycemia, a commonly exhibited metabolic disorder in critically ill patients, activates the body's inflammatory defense mechanism, causing the waterfall release of numerous inflammatory mediators and cytokines, and eventually leads to organ damage. As the only glucose-lowering hormone in the body, insulin not only alleviates the detrimental effects of hyperglycemia through its metabolic regulation, but also directly modulates inflammatory mediators and acts upon immune cells to enhance immunocompetence. In this sense, hyperglycemia is pro-inflammatory whereas insulin is anti-inflammatory. Therefore, during the past 50 years, insulin has not only been used in the treatment of diabetes, but has also been put into practical use in dealing with cardiovascular diseases and critical illnesses. This review summarizes the recent advances regarding the anti-inflammatory effects of insulin in both basic research and clinical trials, with the hope of aiding in the design of further experimental research and promoting effective insulin administration in clinical practice.

Relationship between high dietary fat intake and Parkinson’s disease risk: a meta-analysis

OBJECTIVE: To assess whether dietary fat intake influences Parkinson’s disease risk. DATA SOURCES: We systematically surveyed the Embase and PubMed databases, reviewing manuscripts published prior to October 2018. The following terms were used:(“Paralysis agitans” OR “Parkinson disease” OR “Parkinson” OR “Parkinson’s” OR “Parkinson’s disease”) AND (“fat” OR “dietary fat” OR “dietary fat intake”). DATA SELECTION: Included studies were those with both dietary fat intake and Parkinson’s disease risk as exposure factors. The Newcastle-Ottawa Scale was adapted to investigate the quality of included studies. Stata V12.0 software was used for statistical analysis. OUTCOME MEASURES: The primary outcomes included the relationship between high total energy intake, high total fat intake, and Parkinson’s disease risk. The secondary outcomes included the relationship between different kinds of fatty acids and Parkinson’s disease risk. RESULTS: Nine articles met the inclusion criteria and were incorporated into this meta-analysis. Four studies scored 7 and the other five studies scored 9 on the Newcastle-Ottawa Scale, meaning that all studies were of high quality. Meta-analysis results showed that high total energy intake was associated with an increased risk of Parkinson’s disease (P = 0.000, odds ratio (OR)= 1.49, 95% confidence interval (CI): 1.26–1.75);in contrast, high total fat intake was not associated with Parkinson’s disease risk (P = 0.123, OR = 1.07, 95% CI: 0.91–1.25). Subgroup analysis revealed that polyunsaturated fatty acid intake (P = 0.010, OR = 1.03, 95% CI: 0.88–1.20) reduced the risk of Parkinson’s disease, while arachidonic acid (P = 0.026, OR = 1.15, 95% CI: 0.97–1.37) and cholesterol (P = 0.002, OR = 1.09, 95% CI: 0.92–1.29) both increased the risk of Parkinson’s disease. Subgroup analysis also demonstrated that, although the results were not significant, consumption of n-3 polyunsaturated fatty acids (P = 0.071, OR = 0.88, 95% CI: 0.73–1.05),α-linolenic acid (P = 0.06, OR = 0.86, 95% CI: 0.72–1.02), and the n-3 to n-6 ratio (P = 0.458, OR = 0.89, 95% CI: 0.75–1.06) were all linked with a trend toward reduced Parkinson’s disease risk. Monounsaturated fatty acid (P = 0.450, OR = 1.06, 95% CI: 0.91–1.23), n-6 polyunsaturated fatty acids (P = 0.100, OR = 1.15, 95% CI: 0.96–1.36) and linoleic acid (P = 0.053, OR = 1.11, 95% CI: 0.94–1.32) intakes were associated with a non-significant trend toward higher PD risk. Saturated fatty acid (P = 0.619, OR = 1.01, 95% CI: 0.87–1.18) intake was not associated with Parkinson’s disease. CONCLUSION: Dietary fat intake affects Parkinson’s disease risk, although this depends on the fatty acid subtype. Higher intake of polyunsaturated fatty acids may reduce the risk of Parkinson’s disease, while higher cholesterol and arachidonic acid intakes may elevate Parkinson’s disease risk. However, further studies and evidence are needed to validate any link between dietary fat intake and Parkinson’s disease.

The combination of 1-octyl-3-methylimidazolium tetrafluorborate with TBAB or THF on CO2 hydrate formation and CH4 separation from biogas

[C_8min] BF_4 was used in this work to combine with TBAB or THF for the investigation about thermodynamic and kinetic additives on CO_2 and CH_4/CO_2 hydrates. The results show that [C_8min] BF_4 has the inhibition effect on the equilibrium of hydrate formation. About the kinetic study, [C_8 min] BF_4 could improve the rate of CO_2 hydrate formation and increase the gas uptake in hydrate phase. At the same time, the combination of TBAB and [C8 min] BF_4 could increase the mole friction of CH_4 in residual gas comparing with the data in THF solution. CH_4 separation efficiency was strongly enhanced. Since that the size of CO_2 and CH_4 molecules are similar, CH_4 and CO_2 could form the similar hydrate, so the recovery of CH_4 from biogas decreases lightly. The CH_4 content in biogas can purified from 67 mol% to 77 mol% after one-stage hydrate formation. In addition, the combination of THF and[C_8 min] BF_4 do not have obvious promoting effect on CH_4 separation comparing with the gas separation results in pure THF solution.

Hepatocellular carcinoma-derived exosomal miRNA-761 regulates the tumor microenvironment by targeting the SOCS2/JAK2/STAT3 pathway

BACKGROUND:Exosomes and exosomal microRNAs have been implicated in tumor occurrence and metastasis.Our previous study showed that microRNA-761(miR-761)is overexpressed in hepatocellular carcinoma(HCC)tissues and that its inhibition affects mitochondrial function and inhibits HCC metastasis.The mechanism by which exosomal miR-761 modulates the tumor microenvironment has not been elucidated.METHODS:Exosomal miR-761 was detected in six cell lines.Cell counting kit-8(CCK-8)and transwell migration assays were performed to determine the function of exosomal miR-761 in HCC cells.The luciferase reporter assay was used to analyze miR-761 target genes in normal fi broblasts(NFs).The inhibitors AZD1480 and C188-9 were employed to determine the role of the Janus kinase 2/signal transducer and activator of transcription 3(JAK2/STAT3)signaling pathway in the transformation of cancer-associated fi broblasts(CAFs).RESULTS:In this study,we characterized the mechanism by which miR-761 reprogrammed the tumor microenvironment.We found that HCC-derived exosomal miR-761 was taken up by NFs.Moreover,HCC exosomes aff ected the tumor microenvironment by activating NFs via suppressor of cytokine signaling 2(SOCS2)and the JAK2/STAT3 signaling pathway.CONCLUSIONS:These results demonstrated that exosomal miR-761 modulated the tumor microenvironment via SOCS2/JAK2/STAT3 pathway-dependent activation of CAFs.Our fi ndings may inspire new strategies for HCC prevention and therapy.

Modulation Recognition in Maritime Multipath Channels:A Blind Equalization-Aided Deep Learning Approach

Modulation recognition has been long investigated in the literature,however,the performance could be severely degraded in multipath fading channels especially for high-order Quadrature Amplitude Modulation(QAM)signals.This could be a critical problem in the broadband maritime wireless communications,where various propagation paths with large differences in the time of arrival are very likely to exist.Specifically,multiple paths may stem from the direct path,the reflection paths from the rough sea surface,and the refraction paths from the atmospheric duct,respectively.To address this issue,we propose a novel blind equalization-aided deep learning(DL)approach to recognize QAM signals in the presence of multipath propagation.The proposed approach consists of two modules:A blind equalization module and a subsequent DL network which employs the structure of ResNet.With predefined searching step-sizes for the blind equalization algorithm,which are designed according to the set of modulation formats of interest,the DL network is trained and tested over various multipath channel parameter settings.It is shown that as compared to the conventional DL approaches without equalization,the proposed method can achieve an improvement in the recognition accuracy up to 30%in severe multipath scenarios,especially in the high SNR regime.Moreover,it efficiently reduces the number of training data that is required.