肾移植受者发生肾癌的临床特征和诊治分析

目的:探讨肾移植受者发生肾癌的临床特征和诊疗特点。方法:回顾性分析2011年3月至2023年3月天津市第一中心医院收治的27例肾移植受者发生肾癌患者的临床资料,其中男性25例、女性2例。27例患者中24例行肾癌根治性切除术(包括1例行双侧肾癌根治性切除术、1例行肾输尿管全长切除术),3例行保守治疗。手术方式包括开放、腹腔镜和机器人手术,并对患者的诊疗过程、病理特征和手术预后进行分析。结果:手术中位时间为148(100~210)min,术后中位住院时间为7(4~10)天。24例手术患者为原肾肾癌,肿瘤直径平均为(4.03±2.49)cm,其中6例为肾乳头状细胞癌、1例为肾嫌色细胞癌、17例为肾透明细胞癌。3例行保守治疗中的1例患者发现移植肾肿物,行穿刺活检病理为肾透明细胞癌。27例患者的临床TNM分期分别为T1aN0M0为18例、T1bN0M0为4例、T2aN0M0为2例、T4N1M1为3例。患者首次诊断肿瘤的平均年龄为(51.21±7.60)岁。至移植前中位透析时间为19(1.2~72.0)个月,诊断肿瘤至移植手术的中位时间为95(12~180)个月。27例患者中位随访时间为47(3~147)个月,随访至129个月和95个月后有2例死亡,死亡原因分别为肺炎和脓毒血症。结论:肾移植术后发生肾癌患者的早期诊断较为困难,有多发、囊性变、坏死倾向,重视规范的随访及确定预防性切除术时机尤为重要。

A Potential Role for GLUT4 in Predicting Sepsis in Critically Ill Children

Background: This study investigated serum Glucose transporter (GLUT) 4 levels and examined the relationship between serum GLUT4 levels and sepsis in critically ill children. Methods: This was a retrospective study of 77 critically ill children and 33 non-diabetic healthy children (controls) who were admitted between 07/2015 and 05/2016. Patient data, clinical information, and blood samples were collected on admission, alongside a large number of laboratory parameters that were routinely assessed. Critically ill patients were divided into sepsis and non-sepsis/systemic inflammatory response syndrome (SIRS). Serum GLUT4 was measured using western blotting and enzyme-linked immunosorbent assays. Insulin resistance indexes, clinical data, laboratory parameters, and inflammatory cytokines were assessed. Results: GLUT4 serum levels were higher in critically ill children than in healthy children (90.5 vs. 30.3 μg/L, P 0.05). Compared to healthy children, hyperglycemic patients (n = 48) had elevated GLUT4 serum levels (30.3 vs. 103.7 g/L, P Conclusions: GLUT4 serum levels might be significantly increased in critically ill children compared with healthy children, particularly those in septic shock. Serum GLUT4 could predict disease severity.

Gp78 regulates PMP22 and causes ER stress and autophagy in EV71-VP1-overexpressing mouse Schwann cells

Background:During Enterovirus type 71(EV71)infection,the structural viral protein 1(VP1)activates endoplasmic reticulum(ER)stress associated with peripheral myelin protein 22(PMP22)accumulation and induces autophagy.However,the specific mechanism behind this process remains elusive.Methods:In this research,we used the VP1-overexpressing mouse Schwann cells(SCs)models co-transfected with a PMP22 silencing or Autocrine motility factor receptor(AMFR/gp78)overexpressing vector to explore the regulation of gp78 on PMP22 and its relationship with autophagy and apoptosis.Results:The activity of gp78 could be influenced by EV71-VP1,leading to a decrease in the ubiquitination and degradation of PMP22,resulting in PMP22 accumulation in ER.In VP1-overexpressing mouse SCs,all three ER stress sensors,including pancreatic endoplasmic reticulum kinase(PERK),activating transcription factor 6(ATF6)and inositol-requiring enzyme 1(IRE1)and the related downstream signals(C/EBP-homologous protein(CHOP)and Caspase 12)were activated,as well as the ER-resident chaperone Glucose-regulated protein 78(GRP78).In addition,VP1 upregulated the autophagy marker Microtubule-associated protein 1 light chain 3 beta(LC3B),while PMP22 silencing or gp78 overexpression reversed the phenomenon.Meanwhile,PMP22 silencing or gp78 overexpression increased proliferation of EV71-VP1-transfected mouse SCs.Conclusion:Gp78 could regulate PMP22 accumulation through ubiquitination degradation and cause ER stress and autophagy in EV71-VP1-overexpressing mouse SCs.Therefore,the gp78/PMP22/ER stress axis might emerge as a promising therapeutic target for myelin and neuronal damage induced by EV71 infection.

Distribution and Drug Resistance Analysis of 2287 Strains of Pathogenic Bacteria in Children’s Blood Culture

Background: Bloodstream infection is a serious infectious disease. In recent years, the drug resistance of pathogenic bacteria to commonly used anti-infective drugs has been widely concerned, which also makes the treatment of bloodstream infection face severe challenges. Objective: To explore the distribution characteristics of blood culture-positive pathogens and the resistance to antibacterial drugs, so as to provide clinicians with accurate laboratory evidence, so as to guide clinicians to rationally apply antibiotics, improve clinical treatment effects, and reduce the emergence of drug-resistant strains. Methods: From January 2019 to June 2022, 2287 positive blood culture specimens of patients in Guangzhou Women and Children’s Medical Center were retrospectively analyzed, and the proportion of different pathogenic bacteria, the distribution of pathogenic bacteria in different departments, and the multi-drug resistance of different pathogenic bacteria were counted. Results: Among the 2287 blood culture positive samples, 1560 strains (68.20%) of gram-positive bacteria and 727 strains (31.80%) of gram-negative bacteria were strained. The top three departments in the distribution of pathogenic bacteria were pediatric intensive care unit (600 strains), pediatric internal medicine (514 strains), and pediatric emergency comprehensive ward (400 strains). The pathogens with high detection rates were: Staphylococcus epidermidis (24.09%), Staphylococcus humans (23.74%), Escherichia coli (13.21%) and Klebsiella pneumoniae (8.71%). The pathogens with high multi-drug resistance rates were: Streptococcus pneumoniae (93%), Staphylococcus epidermidis (83.76%), Enterobacter cloacae (75.61%) and Staphylococcus humans (62.43%). Conclusion: In our hospital, gram-positive bacteria were the main pathogenic bacteria in the blood culture of children patients. The children’s intensive care unit was the department with the largest distribution of pathogenic bacteria, and the multiple drug resistance rate of Streptococcus pneumoniae was the highest.

Clinical Analysis of the Relationship between Convulsion and Blood Electrolyte in Children

Objective: Febrile convulsion in children is age-dependent and genetic predisposition. However, mild electrolyte disturbances are not uncommon in such children. This study was to investigate the effect of electrolyte disturbance on febrile convulsion and to screen for febrile convulsion-related genes. Methods: This retrospective cohort study included children who admitted to the Pediatric Emergency Department of Guangzhou Women and Children’s Medical Center due to fever and febrile convulsion between May to December 2020. Clinical manifestations and serum electrolyte levels were recorded and analyzed by binary logistic regression on risk factors of convulsion, and children with family histories were screened for febrile convulsion-related genes. Results: This study included 322 children with fever: 161 in the febrile convulsion group (FC Group) including 71 in the single convulsion group (SC Group) and 90 in the multiple convulsion group (MC Group), and the control group consisted of 161 children with fever without convulsion and nervous system disease. Serum sodium, potassium and calcium in FC Group were lower than those in the control group (p Conclusion: Hyponatremia may be a relative risk factor in febrile convulsion, and for children with a family history of febrile convulsion and serum sodium lower than 133 mmol/L, related gene analysis can be performed.

Children, Influenza, Encephalopathy, Clinical Characteristics, Laboratory Index

Background: To explore the early clinical features and laboratory findings of influenza-associated acute necrotizing encephalopathy (IANE). Methods: The demographics data, clinical manifestations, and laboratory indicators of cases diagnosed with IANE and influenza with febrile convulsions (FS), respectively, admitted to Guangzhou Women and Children’s Medical Center from January 2016 to January 2020 were retrospectively analyzed. Results: Among the 25 cases of IANE, there were 9 males and 16 females, aged 3 to 6 years. The mortality rate was 40.00% (10/25). Influenza virus type A in 9 cases (36.00%) and influenza virus type B in 10 cases (40.00%). The main clinical manifestations of children with IANE were acute disorders of consciousness (64.00%, 16/25) and convulsions (72.00%, 18/25), which were statistically significant when compared with the FS group (P < 0.05). Typical changes on cranial MRI of IANE were cerebral edema, typically with symmetric necrosis of the thalamus and other brain structures. Significant differences (P < 0.05) existed between the IANE and FS groups in laboratory indicators for ALT, AST, CK-MB, LDH, cerebrospinal fluid (CSF) microprotein, CSF LDH, which were above the normal reference range. In addition, logistic regression analysis showed that LDH ≥ 348.5 U/L predicted a significantly higher risk of IANE. Conclusions: Children with influenza present early with acute impairment of consciousness or convulsive seizures, or with elevated AST, ALT, CK-MB, LDH, and CSF protein and CSF LDH, especially if blood LDH is ≥348.5 U/L, should be closely evaluated and alerted to the possibility of IANE.

Risk Factors of Influenza-Associated Necrotizing Encephalopathy in Children

Objective: A case-control study of Influenza-Associated Necrotizing Encephalopathy (IANE) in children was conducted to explore the risk factors for the diagnosis of IANE, and to provide a predictive reference for the diagnosis of IANE. Methods: The children with IANE who received treatment in our hospital from January 2016 to December 2020 were selected as the study group, and the children with Influenza-Associated Encephalopathy (IAE) group who received treatment in the same period were selected as the control group. The blood biochemical, coagulation function and cerebrospinal fluid test results of the two groups were analyzed by univariate analysis. Receiver Operating Characteristic curve (ROC) analysis was used to determine the optimal threshold point of each index for the indicators with statistically significant differences in univariate analysis results, and multivariate Logistic stepwise regression analysis was performed according to the optimal threshold points. Results: In the IANE group, there were 32 children, including 20 males and 12 females, aged 60 (35, 84) months. There were 40 children in IAE group, including 26 males and 14 females, aged 58 (23, 97) months. Univariate results showed that serum Lactate Dehydrogenase (LDH), Cerebrospinal Fluid Lactate Dehydrogenase (CSF LDH) and Cerebrospinal Fluid Protein (CSF PRO) in the IANE group were significantly higher than those in the IAE group, and the difference between the two groups was statistically significant (P < 0.001). The optimal threshold points of blood LDH, CSF LDH and CSF PRO by ROC curve analysis were 535 U/L, 67 U/L and 0.49 g/L, respectively. Further Multivariate Logistic stepwise regression analysis showed that LDH > 535 U/L (OR = 31.264, 95% CI: 5.892 - 165.878, P < 0.001) and CSF PRO > 0.49 g/L (OR = 7.695, 95% CI: 1.052 - 56.305, P = 0.044) were independent risk factors for IANE. Conclusion: For children with influenza whose neurological symptoms appear rapidly and persist in the early stages of the disease, blood LDH > 535 U/L and CSF PRO > 0.49 g/L are independent risk factors for IANE.

Analysis of Factors Influencing the Effect of Red Blood Cell Suspension Infusion in Children

Objective: The related factors of no improvement of hypoxia and ineffective infusion were analyzed to provide new ideas, clinical observation and evaluation pathway for RBC transfusion in clinical children. Methods: Retrospective analysis from January 2020 to December 2020, Guangzhou women and children’s medical center hospital in the emergency observation room of 249 children under 1 month to 18 years of blood cell suspension infusion, analyze the clinical effect of red blood cell infusion and children gender, age, fever after transfusion, disease type, delay transfusion. The possible influencing factors were analyzed by logistic regression. Results: Invalid transfusion was associated with the type of transfusion product (P = 0.032), logistic regression analysis showed that patients infused with washed RBC suspension were 3.231 times more likely to not achieve the expected effect than those infused with RBC suspension (P = 0.025). Failure transfusion was associated with the type of transfusion products. In ineffective transfusion was closely related to post-transfusion fever (P P P = 0.031). Logistic regression analysis showed that fever after transfusion was a risk factor for no improvement of hypoxia (OR = 5.809, P = 0.001), and the improvement of hypoxia in adolescent children was 10.744 times higher than that of infants (0 - 3 years old). Late transfusion hypoxia improvement was 4.212 times more likely to achieve no effect than timely transfusion. If ineffective infusion of red blood cells is considered and hypoxia after transfusion is not improved, univariate suggests a close correlation with fever after transfusion (P = 0.002), logistic regression analysis showed that fever after transfusion was an independent risk factor (OR = 7.258, P = 0.002). Conclusion: There was no correlation between the ineffective transfusion of red blood cells and the type of disease affected in the child. Infusion of red cell suspension has an advantage over the wash red cell infusion. Ineffective RBC transfusion and no improvement in hypoxia after transfusion were closely related to post-transfusion fever, with no difference between children in all age groups. Red blood cell infusion in pediatric clinical treatment activities should pay attention to adolescent children, especially female children to give more attention, and give timely red blood cell infusion as much as possible.

Exploration on Separation of Periplaneta Americana Small Peptides with Tricine-SDS-PAGE System

[ Objective] This study aimed to explore a Tricine-SDS-PAGE method for separation and purification of Periplaneta Americana small peptides. [ Method] By comparing the separation effects of three types of gels with different ratios on P. Americana small peptides, an appropriate Tricine-SDS-PAGE method for separation of small peptides was established. [ Result] Standard low molecular weight Marker was preliminarily separated to a certain extent with polyacrylamide gel electraphoresis, while the sample mixture was not separated due to the different levels of aggregation in separating gel, spacer gel and stacking gel. [Condusion] More appropriate polyacrylamide gel electrephoresis separation method or other better separation methods were to be further explored for separating peptide mixture with smaller molecular weight.

Identification of a chitinase from the hepatopancreas of Chinese black sleeper(Bostrychus sinensis)

Chinese black sleeper(Bostrychus sinensis)is a fish that lives both in seawater and freshwater,feeds on crustaceans,aquatic insects and occasionally shellfish.The existence of digestive enzyme in viscera to act on chitinous exoskeleton of the prey is of interest.In this study,a chitinase was purified to homogeneity using ammonium sulfate precipitation,DEAE-Sephacel ion exchange,Sephacryl S-200 HR and Superdex 200 gel filtration columns.The purified protein presents a molecular mass of 58 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)and results in a single band on native PAGE.According to peptide mass fingerprinting,two peptides containing a total of 20 amino acid residues,were 95%identical to a chitinase from yellow perch(Perca flavescens)and 100%identical to the chitinase from greater amberjack(Seriola dumerili).The purified chitinase showed optimum activity at pH 6.0,and was stable at acidic conditions and temperature below 55℃.The enzymatic activity was quite stable in the presence of NaCl,even at 1 mol/L.The chitinase was capable of degrading chitosan into low molecular mass chitooligosaccharides(COS)with sizes in a range of 200-700 Da,and the circular dichroism profile of the COS greatly differed from native chitosan.Full-length cDNA encoding the present chitinase was cloned and the transcript levels of chitinase in various tissues were determined by quantitative real-time PCR.The results showed that the transcript level of chitinase was highest in esophagus and hepatopancreas.

Antibacterial and antibiofi lm activity of peptide PvGBP2 against pathogenic bacteria that contaminate Auricularia auricular culture bags

Bacteria contamination in Auricularia auricular culture bags reduces yield and increases the risk of food safety.In this study,5 species of bacteria,mainly gram-positive bacteria including three species of Bacillus spp.,Arthrobacter arilaitensis and Staphylococcus warneri,were isolated and identifi ed from bacteria-contaminated A.auricular culture bags.An in silico predicted antimicrobial peptide from theβ-1,3-glucan-binding protein sequence of Penaeus vannamei,designated Pv GBP2(FLKLGRKSRYGMLKL),was screened and its antibacterial effect and mechanism of action on the isolated Bacillus spp.explored.The minimal inhibitory concentrations(MIC)of Pv GBP2 on Bacillus spp.were 15.6–31.25μg/m L.Peptide Pv GBP2 could inhibit Bacillus subtilis in A.auricular culture bags to maintain growth and yield of A.auricular.Transmission electron microscopy(TEM)revealed that Pv GBP2 kills bacteria by perforating the cell wall,destroying membrane integrity and resulting in the leakage of intracellular solutes.In addition,Pv GBP2 inhibits biofi lm formation by B.subtilis by 90.6%at 1×MIC.Thus,peptide Pv GBP2 could be potentially applied as an antibacterial agent to control bacterial infection of A.auricular cultivation and the spread of foodborne pathogens.

A Comparative Study on Four Staining Methods for Antitumor Active Fraction of Periplaneta americana

[ Objective ] This study aimed to compare four staining methods for proteins of SDS-polyacrylamide gel dectrophoresis （SDS-PAGE） and explore a suit- able staining method for the antitumor active fraction of P. americana after polyacrylamide gel electrophoresis. [ Method ] BSA was used as the standard for the comparison of Coomassie brilliant blue staining method, potassium staining method, calcium staining method and silver staining method, on the basis, antitumor ac- tive fraction samples of P. americana were used for SDS-PAGE electrophoresis and staining. [ Result] The results showed that silver staining method could be ac- curately, quickly and easily used for SDS-PAGE staining of the antitumor active fraction of P. amer/cana. [ Conclusion] This study laid the foundation for explo- ring the medicinal value of P. americana.

The immunoreactivity of Cra a 4 decreased after Maillard reaction with xylose and glucose

Cra a 4 is a heat stable allergen in oyster,the effect of Maillard reaction on the immunoreactivity and structure of Cra a 4 was investigated.Firstly,Cra a 4 was cloned,expressed and identified.The purified Cra a 4 was incubated with xylose at 100℃,pH 8.5 for 30 min or with glucose for 60 min.After Maillard reaction,the IgE-binding activity of Cra a 4 and in vitro digested samples was reduced by about 50%.The unfoldα-helix and higher surface hydrophobicity of glycated Cra a 4 were identified as the reason for hypo-immunoreactivity.The higher frequency of lysine(13%)in the primary structure and exposure on the surface of the spatial structure was attributed to the hypo-immunoreactivity of Cra a 4 after Maillard reaction.It comprehensively evaluated the effects of Maillard reaction on Cra a 4 and provids new methods for the industrial production of hypoallergenic oyster.The modified Cra a 4 by Maillard reaction could be a hypoallergenic therapeutic agent for allergy to oyster.

Identification of Age-associated Proteins and Functional Alterations in Human Retinal Pigment Epithelium

Retinal pigment epithelium(RPE)has essential functions,such as nourishing and supporting the neural retina,and is of vital importance in the pathogenesis of age-related retinal degeneration.However,the exact molecular changes of RPE during aging remain poorly understood.Here,we isolated human primary RPE(h RPE)cells from 18 eye donors distributed over a wide age range(10–67 years old).A quantitative proteomic analysis was performed to analyze changes in their intracellular and secreted proteins.Age-group related subtypes and age-associated proteins were revealed and potential age-associated mechanisms were validated in ARPE-19 and h RPE cells.The results of proteomic data analysis and verifications suggest that RNF123-and RNF149-related protein ubiquitination plays an important role in protecting h RPE cells from oxidative damage during aging.In older h RPE cells,apoptotic signaling-related pathways were up-regulated,and endoplasmic reticulum organization was down-regulated both in the intracellular and secreted proteomes.Our work paints a detailed molecular picture of h RPE cells during the aging process and provides new insights into the molecular characteristics of RPE during aging and under other related clinical retinal conditions.

基于决策树法构建创伤性颅脑损伤术后硬脑膜下积液的风险预测模型

目的:探讨创伤性颅脑损伤(TBI)术后硬脑膜下积液(PTSH)的影响因素,并构建TBI术后PTSH的决策树风险预测模型。方法:选取成都市郫都区人民医院重症医学科自2019年6月至2022年6月收治的344例TBI患者作为研究对象,根据是否发生PTSH将其分为观察组和对照组,分析2组患者的临床资料,采用单因素和Logistic回归分析筛选TBI患者发生PTSH的影响因素,采用SPSS Modeler软件构建TBI术后PTSH的决策树预测模型,并分析决策树预测模型的诊断效能。结果:344例TBI患者行DC后发生PTSH者68例,发生率为19.77%;单因素和多因素Logistic回归分析结果显示,蛛网膜撕裂、入院GCS评分>8分、中线移位、大骨瓣、骨窗面积>150 cm2、骨瓣边缘距中线距离>2 cm是TBI患者行DC后发生PTSH的影响因素(P<0.05);决策树模型选出了蛛网膜撕裂、入院GCS评分>8分、中线移位、大骨瓣、骨窗面积>150 cm^(2)、骨瓣边缘距中线距离>2 cm等6个解释变量作为模型的节点,其中蛛网膜撕裂是最重要的预测因子。ROC曲线分析显示,决策树模型的曲线下面积(AUC)值为0.895,Logistic回归模型的AUC值为0.881,决策树模型的预测效能优于Logistic回归模型(Z=2.423,P=0.013)。结论:蛛网膜撕裂、入院GCS评分>8分、中线移位、大骨瓣、骨窗面积>150 cm^(2)、骨瓣边缘距中线距离>2 cm是TBI患者行DC后发生PTSH的影响因素,构建的决策树模型有助于筛查DC后发生PTSH高风险人群和指导临床制定科学的防治策略,具有较高的临床价值。

P91和Super304H钢表面涂覆NaCl在高温水蒸汽中的腐蚀行为

在海洋性大气中,沉积在金属构件表面的NaCl在高温环境中可能导致金属加速腐蚀。在600°CNaCl和水蒸汽环境中,研究了P91钢和Super304H钢的腐蚀行为。采用XRD,SEM/EDS对腐蚀产物膜相组成和形貌进行了分析。结果表明,P91钢和Super304H钢均表现为失重,受到严重腐蚀。样品表面的腐蚀产物层中有大量裂纹和孔洞,导致腐蚀产物大量剥落。P91钢表面腐蚀产物主要由Fe2O3组成。Super304H钢由(Fe,Cr,Ni)3O4和NiO组成。由于Cr2O3膜在NaCl和高温水蒸汽中受到严重破坏,两种合金均遭到严重腐蚀,含Cr量较高的Super304H钢比P91钢腐蚀更严重,且有明显的晶间腐蚀发生。

铁浴反应器多段侧吹混合特性数值模拟

在厚渣层铁浴熔融还原反应器水模实验的基础上,通过数值模拟的方法研究了双层侧枪在不同喷吹角度(40°,45°,50°)和不同水平插入深度(60,120,180 mm)条件下对熔池的搅拌情况的影响,通过水模型实验验证了数值模拟的准确性。通过观察气液两相流中熔池的流场以及示踪剂在熔池中的流动扩散情况,分析弱流区和死区的占比以及不同侧吹条件下的混匀时间,结果表明,侧枪水平插入角度对熔池搅拌的影响较水平插入深度更显著,侧枪的水平插入角度和深度影响熔池中产生的回旋流区域和回旋流个数,当侧枪水平插入角度越大,水平插入深度越深时,熔池中弱流区或死区的体积占比越小,越有利于熔池搅拌混匀。最佳的喷吹条件为上层喷吹角度50°及插入深度60 mm、下层喷吹角度50°及插入深度120 mm。研究了不同气流量对熔池混匀情况的影响,得出上下枪单支气流量分别为8.58和10.43 Nm^(3)/h时,熔池的混匀时间最短。

Successive digestion of tilapia collagen by serine proteinase and proline specific endopeptidase to produce novel angiotensin l-converting enzyme inhibitory peptides

Serine proteinase,purified from the hepatopancreas of Pacific white shrimp(Litopenaeus vannamei), was used to hydrolyze acid solubilized collagen(ASC)isolated from Nile tilapia(Oreochromis sp.)skin to produce angiotensin I-converting enzyme(ACE)inhibitory peptides(ACEIPs).A series of column chromatography assays were used to separate the ACEIPs.A peptide,NPARTCR,was isolated as it exhibited high ACE inhibition potential.Further digestion of this peptide by a proline specific endopeptidase(PSEP),produced a pentapeptide ARTCR with ACE inhibitory activity(IC_(50))of 77.0 pmol/L.Both NPARTCR and ARTCR inhibited ACE in a non-competitive manner.An in vivo study in rats demonstrated that ARTCR has ACE inhibitory activity via lowering systolic blood pressure in spontaneously hypertensive rats(SHRs).These results suggest that processing by-products from shrimp and tilapia are ideal raw materials for the production of serine proteinase and collagen,respectively.Serine proteinase and collagen are both ideal raw materials that can be used to derive ACE inhibitory active peptides against hypertension.

Channel Drop Out: A Simple Way to Prevent CNN from Overfitting in Motor Imagery Based BCI

With the development of deep learning, many motor imagerybrain-computer interfaces based on convolutional neural networks(CNNs) show outstanding performances. However, the trial number ofEEG in the training set is usually limited, and redundancy extensivelyexists in multiple channel EEG. Thus, overfitting often appears in CNNbased motor imagery recognition model and greatly affects the performancesof model. In this paper, channel drop out is proposed to addressthis problem by data augmentation and ensemble learning. Specifically,one of all EEG channels will be dropped and replaced by the mean signalof all EEG channels. In this way, the trial number in the training setwas enlarged by channel drop out. And at the testing stage, all the EEGtrials processed by channel drop out were fed to the CNN model and theaverage output probabilities of them were applied to determine the prediction.The experiments were conducted on two popular CNN modelsapplied in motor imagery BCI and BCI Competition IV datasets 2a toverify the performances of the proposed channel drop out approach. Theresults show that average improvements provided by channel drop outin two-category or four-category motor imagery classification are 2.83%and 2.65% compared with the original CNN model. So the channel dropout approach significantly improves the performances of motor imagerybased BCI.