Aiming at traffic sign problem, the traditional LeNet-5 network structure has low accuracy of traffic sign recognition, slow identification speed and ignores natural factors such as weather. A convolutional network structure model with two-channel and multi-scale based on LeNet-5 improvement is proposed by convolutional neural network technology. In the dual-channel structure, each channel contains two branching structure, and the number of convolution and image scale of each channel is different, making the feature extraction of different image scales richer. Secondly, the improved network structure greatly increases the number of convolutional kernels compared to the traditional LeNet-5 network structure. Finally, by changing the Sigmoid activation function to the ReLu activation function, changing the stochastic gradient descent algorithm to the Adam algorithm, and adding Dropout layers to prevent overfitting and setting the learning rate, thus increasing the traffic sign recognition rate. The recognition rate of the improved network is 98.6%, floating by 0.5%, relative to the traditional LeNet-5 network structure, the recognition rate increases by more than 15%, verifying that the improved network structure has a certain robustness.
In order to investigate the effect of high temperature on the performance of three high viscous asphalt in company with various aging degrees (ADs), multiple stress creep recovery (MSCR) test was employed. CRR and irrecoverable compliance were also carried out to measure the high temperature resistance of high viscous asphalt to external loading in the presence of various aging conditions (ACs) as well as to examine the sensitivity of high viscous asphalt towards the stress. The findings of the study demonstrated that after short- and long-term aging, the high-viscosity asphalt turned harder. Also, type I high-viscosity asphalt was observed to have the greatest deformation resistance acted upon by various stress fields and ACs. Furthermore, in company with various ACs, while the average creep recovery rate (CRR) of Type I and Type II high-viscosity asphalt was found to be higher than that of the SBS modified asphalt, the average irrecoverable compliance was observed to be smaller. This indicated the significant effect of high-viscosity modifiers on the improvement of the elastic recovery performance of asphalt and its resistance to high temperature flow deformation. Contrary to the order of their CRRs, the magnitude of stress sensitivity of the three high-viscosity asphalt at various ADs was observed to be type II < type I < SBS modified asphalt, indicating a good negative correlation between stress sensitivity and average CRR. Furthermore, the obtained results revealed that, in the presence of various ACs, the high temperature viscoelastic qualities of high viscosity modified asphalt is considered by the MSCR test. Also, to comprehensively evaluate the high temperature performance of high viscosity modified asphalt at various Ads, the use of such indexes as the average CRR, average irrecoverable compliance and stress sensitivity coefficient were essential.
针对大规模自组网技术MAC(medium access control)协议中的动态时隙分配算法在模拟仿真测试环境中存在的需要进行大量代码重构及可视化呈现差等问题,以及在实物组网测试时存在的测试环境搭建困难、测试成本高和测试效率低等问题,提出一种新的测试方法.该测试方法使用纯软件来模拟各个节点不同的业务量及拓扑结构,无需实物组网即可方便地重复验证大规模自组网环境中的动态时隙分配情况是否符合预期,同时对测试结果进行精准可视化呈现.实验结果表明,该测试方法能够准确验证大规模、高业务并发场景下的动态时隙分配情况,并对动态时隙分配算法的设计、开发及优化过程加以指导,从而提高研究效率.该测试方法已在多个项目中成功应用并取得良好效果.
In order to meet the requirements of traceability of clinical p27 protein measurement results,reference materials of avian leukosis virus p27 protein lyophilized powder were developed.The value of the reference materials of avian leukosis virus p27 protein lyophilized powder were evaluated by HPLC-IDMS/MS in several laboratories,and the certified values were(1.46±0.13)mg/mL.The developed method is accurate and reliable,it is able to be applied for the development of p27 protein reference material.The result indicated that the reference materials were sufficient homogeneity and had good stability,could be stored for up to 7 days at-20℃,4℃and room temperature.It could be stored for 6 months at-70℃.The development of p27 protein reference material is important for quality control of avian leukemia assays and for the evaluation of different avian leukemia assays.
In order to establish a suitable hydrolysis method for bound amino acid content(BAA)in plant leaf,an amino acid analyzer was used for the determination of BAA in four plant leaves.The chromatography analysis was achieved using zuixinZG diode,sodium chromatographic column(125 mmHR),post-column derivation method.The detection wavelength was 570 nm and 440 nm and the test method was single point calibration method.The effect of different hydrolysis methods,including conventional hydrochloric acid,phenol+hydrochloric acid,β-mercaptoethanol(BME)+ hydrochloric acid,performic acid+hydrochloric acid,on 17 amino acids and total amount of BAA in plant leaves was investigated.The results showed that the hydrolysis method of performic acid was suitable for the determination of sulfur-containing amino acids in rice and wheat leaves,and the hydrolysis method of BME+hydrochloric acid was suitable for the determination of BAA in leaves of four plants.After hydrolysis with BME+hydrochloric acid for 26 h,the contents of most polar positive and non-polar amino acids reached the maximum.When 0.80%BME was added,the contents of polar positive,negative amino acids,tyrosine and cystine in neutral amino acids,and most non-polar amino acids reached the maximum.The method is simple operation,reproducible and stable,and suitable for the determining of BAA in plant leaves.
Reproductive tract infection(RTI)during pregnancy is one of the common diseases threatening the health of women and fetal.To shorten the long duration of existing methods,the rapid detection of reproductive tract pathogens based on loop mediated isothermal amplification(LAMP)was optimized.By LAMP detection system of G.vaginalis,length and GC content were used as parameters for loop primer screening,and the amplification rate(Ct value)of different loop primers were statistically analyzed.The positive effect of loop primer was verified,and the effects of length and GC contents on the amplification rate were explored,which was applied as a screening parameter for rapid detection of G.vaginalis,S.agalactiae and E.faecalis.The results showed that the amplification was not affected by GC content,while the length of the loop primer was a key factor to improve amplification efficiency,and loop primer with less bases significantly accelerate the LAMP amplification(p<0.05).The designed primer sets GV-1,GBS-132 and EF-3 present a complete"S"amplification curve within 30 minutes for pathogens at 105 CFU/mL concentration,which have good potential for clinical screening.
In order to screen lactic acid bacteria with cholesterol-lowering ability and excellent probiotic properties,103 strains of lactic acid bacteria were isolated from 28 Sichuan traditional pickle juice.From the in vitro cholesterol degradation ability,acid resistance and bile salt resistance,artificial gastrointestinal fluid tolerance,salt tolerance,hydrophobicity,self-aggregation,and antibacterial ability Lactiplantibacillus plantarum LAB4 with an in vitro cholesterol degradation ability of 42.7%was isolated.Moreover,Lactiplantibacillus plantarum LAB4 showed promising probiotic characteristics with remarkable tolerance to pH,bile salt and 2%NaCl.Furthermore,the strain could reach 108 CFU/mL after incubation in artificial gastrointestinal fluid and possesses good potential for adhesion and colonization of intestinal epithelial cells;LAB4 showed good intestinal colonization potential,and its fermentation supernatant showed moderate antibacterial activity against four common food-borne pathogens.In summary,Lactiplantibacillus plantarum LAB4 can be used as a potential strain for developing cholesterol-lowering functional foods.
In this paper,the novel coronavirus Raman-labeled immunoassay test strips were prepared with a probe of Au-MGITC@SiO2 core-shell structure.Various respiratory viruses including SARS-CoV-2,229E,NL63,OC43,PR8 were detected by using the test strips.The performance of the test strips was evaluated by testing the coloration and Raman spectrum of the T-line.The experimental results demonstrate the high sensitivity and specificity of our test strips.The SARS-CoV-2 Raman detection limit of 3.5×10-1 PFU/mL was detected.The test strips don’t react with the three coronaviruses 229E,NL63,OC43 and PR8 influenza virus.For the weak positive case,the T-line coloration is not obvious,the Raman spectrum detection is required for further discriminating.This work provides an new detection technology of SARS-CoV-2,which may be useful for the application of Raman labeled immunochromatography in the rapid detection of SARS-CoV-2.
A dilute-and-shoot based ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-QTOF-MS)method was developed for rapid analysis of 20 fat-soluble synthetic dyes in chilli powders.The target synthetic dyes including Sudan dyes were extracted with water/acetonitrile/acetone(v/v/v=2/3/3),followed by a 5-fold dilution with methanol containing 0.1%formic acid before UPLC-QTOF-MS analysis.The pretreatment and analysis conditions were optimized in the process.The optimized method facilitated the separation and detection of the twenty dyes within 8 min,and indicated good sensitivity with LOQ of 1-40 μg/kg.Recovery rates ranged between 54.72%and 117.77%for all the analytes with RSDs of 0.56%-16.27%.The developed method was applied for the detection of the target dyes in 30 chilli powder samples and all the samples were tested negative.Allowing the determination of the target dyes with the advantages of simple pretreatment,short extraction time,as well as being solvent-saving and easy to operate,the dilute-and-shoot procedure meets the requirements of green analysis.
In order to solve the problem that nano carbon dots have no reference substance and it is difficult to quantify,a method for the determination of the content of carbon dots in cells and tissues was established by using pure fluorescent compounds as alternative reference materials based on the stable fluorescence of carbon dots.Carbon points with good imaging performance were used as candidate carbon points,and cresol violet and Rhodamine 6G were used as control materials to determine the content of candidate carbon points and their folate coupling HeLa in cells and biological tissues and their methodological verification were established.The three candidate carbon points DCCDs,ACUCDs,UCPG-Fe and their folate couples had good linear relationship in a certain concentration range in HeLa cells and tissues(r2=0.9933-0.9992),the average recovery was 86.61%-102.5%,and the precision RSD was 2.82%-3.91%.The concentration of DCCDs and FA-DCCDs were 0.1255-0.2665 μg/mL and 0.8917-1.239 μg/mL at 3 h,6 h,9 h and 12 h of uptake respectively.The carbon content of DCCDs in liver and kidney tissue at 20,30,40,50,60,70 min of uptake was 1.132-1.756 μg/mL and 0.3358-0.7043 μg/mL,respectively.The established method is suitable for the determination of carbon dots in cells and liver and kidney tissues.It provides a research basis for quality control for the further research of fluorescent carbon dots in biological diagnosis and treatment,and also provides a new idea for the establishment of quantitative methods for nanomaterials.
To product highly purified diphtheria toxin mutant cross reacting material 197(CRM197),it can be used as a carrier protein for the development of bacterial conjugate vaccines.In this current work,the CRM197 gene was codon-optimized in Escherichia coli and cloned into pET28a(+),and the correctly identified recombinant plasmid pET28a-CRM197 was transformed into Escherichia coli BL21(DE3).The recombinant plasmid was induced by IPTG,and its expression form was analyzed and optimized expression conditions.Then the expressed recombinant CRM197 protein was purified,and finally purified CRM197 was analyzed by western blotting WB,purity,molecular weight and circular dichroism(CD).The results showed that the recombinant plasmid pET28a-CRM197 was successfully constructed by PCR digestion and sequencing,and it was transformed into Escherichia coli BL21(DE3)to obtain recombinant engineering bacteria E.coli(DE3/p28a/197).The optimal inoculum amount for fermentation was 5%-10%(v/v),and it was mainly expressed in a form of inclusion body.The harvested cells were crushed under the condition of crushing pressure of 1000 bar,and then dissolved with 6mol/L guanidine hydrochloride,refolded and ultrafiltered by centrifugal filters(30 kD),and then purified by AKTA pure150 M system,and purified by one-step anion exchange chromatography.The purity of CRM197 was more than 98%,and the identification results of WB,molecular weight and circular dichroism are all consistent with the standard product. The results indicated that CRM197 expression system was established,which has no label,high yield and purity,and can be used for the large-scale production of the protein.
In order to optimize the sample volume of nucleic acid extraction under oscillating motion,the equal frequency motion control algorithm is applied to the nucleic acid extraction process.By improving the stability of the nucleic acid extraction process,the sample volume of nucleic acid under oscillating motion is effectively improved.Based on the STM32 high precision control platform,the step motor was controlled by equal frequency discretization.The Sigmoid curve was used to realize the acceleration and deceleration process,and the smooth and accurate control of the step motor was realized.The proposed constant frequency discrete acceleration and deceleration motion control algorithm solved the problem of unstable speed change in the process of variable speed.Compared with equal-time sampling,the experimental results show that under the same experimental parameters,the method of equal-frequency discretization can achieve the target frequency faster than that of equal-time discretization.Compared with the equal time discretization method,the equal frequency discretization method improves the positioning accuracy by 39.47%.In the application of nucleic acid extraction,the constant frequency dispersion method can effectively improve the nucleic acid sample volume by 20.62 μL compared with the constant time dispersion method.Compared with the traditional Sigmoid function model to realize the S-curve acceleration and deceleration control algorithm,the equal frequency discrete method can improve the positioning accuracy of motion and make the extraction process smoother,and effectively improve the sample volume under the oscillating motion of nucleic acid extraction.
To achieve real-time detection of foodborne pathogenic bacteria in various scenarios,and to address the time-consuming steps of bacterial enrichment and cultivation process in conventional and rapid testing techniques,thereby reducing the testing time and requirements for experimental environment and equipment.The study focused on Bacillus cereus as the research subject.It employed a dual-membrane enrichment method to enrich Bacillus cereus from the samples,and magnetic beads were used to extract and purify trace amounts of DNA,replacing the bacterial enrichment and cultivation process.Simultaneously,the study integrated the loop-mediated isothermal amplification-PCR(LAMP)reaction with a microfluidic chip,effectively avoiding aerosol contamination issues during LAMP amplification.The experimental results showed that the use of the dual-enrichment microfluidic technology for detecting Bacillus cereus in food can reduce the testing time from the current national standard of 5-7 days to within 1 hour.The method exhibited good specificity with a detection limit of 10 CFU/g(mL),equivalent to the existing national standard.Moreover,the coefficient of variation of Ct values is less than 5%,indicating a high level of reproducibility.The established dual-enrichment microfluidic technology for rapid detection of Bacillus cereus in food enables real-time and rapid testing of foodborne pathogens,providing technical support for swift response and prevention of food safety incidents and public opinion risks caused by foodborne pathogens.
In view of the problems that most of the current researches on crop nutrient deficiency mainly use traditional laboratory chemical methods,morphological methods and fertilization methods,etc.,which have high detection cost and damage to the plants themselves,and are not suitable for promotion and use in actual agricultural production.This paper proposes a hyperspectral analysis and image processing method,attempts to use a new handheld hyperspectral camera directly to the outdoor potato demonstration base for field shooting,builds a 1D-CNN network structure based on the spectral curve differences of different hyperspectral images,extracts the region of interest and carries out label processing.The hyperspectral image data sets of normal,nitrogen,phosphorus and potassium deficiency potato plants in natural environment were established.A comparison experiment was carried out on the classification and recognition of vegetative deficient potato plants based on PCA feature extraction and feature selection method based on SVM.The conclusion showed that the total recognition rate of vegetative deficient plants increased from 91.7%to 93.1%after dimension reduction by PCA feature extraction to 20.Under the condition of ensuring accurate recognition rate,dimension reduction treatment could greatly improve the running speed.Compared with feature band selection,feature extraction is more suitable for this lossless qualitative research,It provides a new idea for monitoring crop growth by hyperspectral technology.
Currently,most of the available technologies for medical diagnosis rely on separation based on cell biological properties,which suffer from problems such as low sensitivity,complex technical procedures,low cost-effectiveness,and unsuitability for continuous monitoring.Therefore,this work proposes a new microfluidic technology based on deep learning to adapt to the accurate detection of circulating tumor cells in a high-flow environment.To assist in positioning the detection frame,a finite element analysis software was used to simulate the generation process of microfluidic droplets in the water phase(dispersion phase)and oil phase(continuous phase)at different flow rates,so as to select the most stable flow rate(dispersion phaseat 1 μL/min and continuous phase at 16 μL/min,accordingly).To verify the results of simulation,positioning tests were conducted on videos with different flow rates,and the relative error was controlled within 1%via the pixel and scale optimization of the detection frame.On this basis,the YOLOv5 algorithm structure was optimized by adding an attention mechanism and a multi-scale feature fusion algorithm module,converting the pixels and scales of the detection frame,thereby achieving precise droplet detection and size prediction.In the experiment,lung cancer and breast cancer cells were added into the water phase to construct a data set(15 min,20 F/s)for algorithm model training.Finally,the improved YOLO micro-total analysis system could accurately measure the position(mean average precision of 98.92%)and size(relative error of 0.49%)of the droplets,and precisely identify circulating tumor cells in the video stream with an accuracy of 72.49%.This work not only provides a new technology for the intelligent detection of components in microfluidic droplets,but also provides a potential strategy for real-time monitoring of circulating tumor cells in real blood environment.
An ultra-performance liquid chromatography-ultraviolet(UPLC-UV)method for the rapid determination of mitotane in plasma was established in therapeutic drug monitoring.The plasma samples were separated by C18(2.1 mm×50 mm,1.7 μm)column after precipitating the protein with acetonitrile,and eluted by using acetonitrile∶water(78∶22,v/v)as mobile phase with a flow rate of 0.3 mL·min-1 and a column temperature of 40℃.It was detected at a wavelength of 230 nm and quantified by the external standard method.Mitotane retention time was 1.38 min,the limit of quantitation(LOQ)was 0.5 μg·mL-1,the standard curve linear range was good in the range 0.5-50 μg·mL-1 with the linear regression equation was y=6 213x+197(r2>0.999),the average recovery of the pretreatment was greater than 99%;the precision within the batch was 1.70%-6.63%,and the accuracy was-6.56%-11.08%,the inter-batch precision was 3.99%-8.64%,and the accuracy was-0.62%-1.90%.This method is sensitive,accurate,fast and simple,and suitable for the clinical monitoring of mitotane concentration in plasma.
A high performance liquid chromatography method was established for the detection of asparagine(Asn)and glutamine(Gln)in special medical purpose food(FSMP)using enzyme hydrolysis-dansyl chloride pre-column derivatization.After the sample was enzymatically hydrolyzed by streptomyces griseus protease(Pronase E),the supernatant was collected and subjected to pre-column derivatization with Dns-Cl.The derivatized product was applied to an Agilent Zorbax SB-C18 chromatography column(250 mm×4.6 mm,5 μm).The separation was performed using a 10 mM solution of disodium hydrogen phosphate(pH 6.5)and methanol as the mobile phase for gradient elution and quantification using an external standard method.The results indicate that the two amino acids are present at a concentration of 0.500-50.0μg/mL.The linearity is good within the concentration range of g/mL(R≥0.999),the recovery rate is 95.3%-105%and the RSD is 0.95%-3.22%.The method was validated for enzymatic digestion efficiency and measured content using two protein standards,with good accuracy(δ<10%).The method fills the gap in detection methods for Asn and Gln in FSMP,can be used to detect Asn and Gln content in FSMP,and is currently being used to develop national food safety standards.
To address the detection problem of low accuracy of micro-column gel card blood group analyzer interpretation,this paper designs a fully automated blood group detection system based on machine vision.The system is designed to improve the reading accuracy of the system through relevant feature extraction algorithms and image recognition algorithms.In the feature extraction algorithm,this paper adopts an image processing algorithm combining color channel separation and merging and entropy processing to extract color features and grayscale features in blood type images,so as to improve the image analysis.In the image recognition algorithm,this paper designs an improved classification neural network model based on AlexNet network model for training and prediction.In which,a channel attention mechanism is added to the network structure to assign weights to expand the influence of features on the results.In the training parameters,Adam optimizer,multi-classification cross-entropy loss function optimization and learning rate fixed-step decay strategy for tuning the parameters are used,which helps to speed up the convergence of the model and improve the accuracy of the model.Afterwards,this paper designs the interpretation interface for system debugging.The experimental results show that using the designed fully automated blood group detection system,most of the blood group images can be accurately detected with an increased accuracy of up to 97.516%compared to the original 93.789%.And the final test results of the gel cards can be effectively interpreted in conjunction with the blood group testing tests performed.The blood group interpretation technique used in this paper is effective for microcolumn gel card testing and can greatly improve the interpretation accuracy of the detection system.
To evaluate the performance of Proofman probe-based ladder-shape melting temperature isothermal amplification(LMTIA)for nucleic acid detection,Proofman-LMTIA rapid detection of canine parvovirus was taken as an example,real-time fluorescence quantitative PCR method and droplet digital PCR method were used for comparative analysis.Primers and Proofman probes were designed for the specific sequence of CPV gene.The specificity and sensitivity of the method were tested by optimizing reaction conditions,and then verified by real-time fluorescence quantitative PCR and droplet digital PCR.The results showed that when the optimal reaction temperature was 61℃,the established Proofman-LMTIA method had no cross-reaction with cat,dog and other genomic DNA,and the sensitivity reached 8 copies/µL,and the detection could be completed within 20 min,which was consistent with the results of real-time fluorescence quantitative PCR and digital PCR.The method not only can be amplified under isothermal conditions,but also has the advantages of fast,sensitive and efficient,which is suitable for the rapid detection of viruses in the field.
