A New Deep Model for Detecting Multiple Moving Targets in Real Traffic Scenarios: Machine Vision-Based Vehicles.

When performing multiple target detection, it is difficult to detect small and occluded targets in complex traffic scenes. To this end, an improved YOLOv4 detection method is proposed in this work. Firstly, the network structure of the original YOLOv4 is adjusted, and the 4× down-sampling feature map of the backbone network is introduced into the neck network of the YOLOv4 model to splice the feature map with 8× down-sampling to form a four-scale detection structure, which enhances the fusion of deep and shallow semantics information of the feature map to improve the detection accuracy of small targets. Then, the convolutional block attention module (CBAM) is added to the model neck network to enhance the learning ability for features in space and on channels. Lastly, the detection rate of the occluded target is improved by using the soft non-maximum suppression (Soft-NMS) algorithm based on the distance intersection over union (DIoU) to avoid deleting the bounding boxes. On the KITTI dataset, experimental evaluation is performed and the analysis results demonstrate that the proposed detection model can effectively improve the multiple target detection accuracy, and the mean average accuracy (mAP) of the improved YOLOv4 model reaches 81.23%, which is 3.18% higher than the original YOLOv4; and the computation speed of the proposed model reaches 47.32 FPS. Compared with existing popular detection models, the proposed model produces higher detection accuracy and computation speed.

Fault Diagnosis of Permanent Magnet Synchronous Motor Based on Stacked Denoising Autoencoder.

As a complex field-circuit coupling system comprised of electric, magnetic and thermal machines, the permanent magnet synchronous motor of the electric vehicle has various operating conditions and complicated condition environment. There are various forms of failure, and the signs of failure are crossed or overlapped. Randomness, secondary, concurrency and communication characteristics make it difficult to diagnose faults. Meanwhile, the common intelligent diagnosis methods have low accuracy, poor generalization ability and difficulty in processing high-dimensional data. This paper proposes a method of fault feature extraction for motor based on the principle of stacked denoising autoencoder (SDAE) combined with the support vector machine (SVM) classifier. First, the motor signals collected from the experiment were processed, and the input data were randomly damaged by adding noise. Furthermore, according to the experimental results, the network structure of stacked denoising autoencoder was constructed, the optimal learning rate, noise reduction coefficient and the other network parameters were set. Finally, the trained network was used to verify the test samples. Compared with the traditional fault extraction method and single autoencoder method, this method has the advantages of better accuracy, strong generalization ability and easy-to-deal-with high-dimensional data features.

Efficacy of solution form of ethylenediaminetetraacetic acid on removing smear layer of root canal at different exposure time In Vitro.

This study was aimed to evaluate the effectiveness of solution form of 17% ethylenediaminetetraacetic acid (EDTA) on removing smear layer of root canals at different exposure time periods and to provide scientific basis for EDTA as a choice of root canal irrigation in clinical practice. Twenty-five single-rooted teeth were randomly divided into 5 groups: control group (group A) was given 2.5% NaOCl, and 4 experimental groups were given 2.5% NaOCl and 17% EDTA, including groups B, C, D and E with exposure time of 1, 3, 5 and 7 min, respectively. After preparation of the root canals, the teeth were split along their longitudinal axis, and the root sections were examined under scanning electron microscope for evaluation of smear layer removal and erosion on the surface of the root canal walls. The specimens in group B showed presence of smear layer on the walls of the root canal with no statistical difference from that in group A (P>0.05). In groups C and D, partial removal of smear layer was obtained, and there was no significant difference between the two groups (P>0.05), but there was significant difference in removal of smear layer between group C and group B (P<0.05). Root canal walls in group E specimens showed almost complete removal of smear layer, and the removal of smear layer was significantly different from that in group D (P<0.01). There was no significant change in the structure of the surface of root canal for each sample. It was concluded that combined irrigation with 17% EDTA and 2.5% NaOCl could remove the smear layer with no significant alteration in dentinal structure when the chelating agent was applied for 7 min. At 3 and 5 min of application, partial removal of smear layer was observed and at 1 min negligible removal of smear layer was achieved.

Autophagy in homocysteine­induced HUVEC senescence.

The senescence of vascular endothelial cells (VECs) drives the occurrence and development of cardiovascular disease (CVD). Homocysteine (HCY) is a general risk factor for age-associated CVDs. Autophagy, an evolutionarily conserved lysosomal protein degradation pathway, serves a part in VEC senescence. The purpose of this study was to investigate the role of autophagy in HCY-induced endothelial cell senescence and explore novel mechanisms and therapeutic approaches for related CVDs. Human umbilical vein endothelial cells (HUVECs) were isolated from fresh umbilical cords of healthy pregnancies. Cell Counting Kit-8, flow cytometry and senescence-associated (SA) ß-galactosidase (Gal) staining demonstrated that HCY induced HUVEC senescence by decreasing cell proliferation, arresting cell cycle and increasing the number of SA-ß-Gal-positive cells. Stub-RFP-Sens-GFP-LC3 autophagy-related double fluorescence lentivirus revealed that HCY increased autophagic flux. Further, inhibition of autophagy using 3-methyladenine increased HCY-induced HUVEC senescence. By contrast, the induction of autophagy via rapamycin alleviated HCY-induced HUVEC senescence. Finally, the detection of reactive oxygen species (ROS) with ROS kit showed that HCY increased intracellular ROS, whereas induction of autophagy reduced intracellular ROS. In conclusion, HCY increased HUVEC senescence and upregulated autophagy; moderate autophagy could reverse HCY-induced cell senescence. Autophagy may alleviate HCY-induced cell senescence by decreasing intracellular ROS. This provides insight into the underlying mechanism of HCY-induced VEC senescence and potential treatments for age-associated CVDs.

[Epidemiological characteristic of first case of locally identified A/H1N1 secondary cases caused by imported source of infection in China].

OBJECTIVE: To study the first locally identifed A/H1N1 secondary cases outbreak in China. METHODS: Interview and field investigation were integrated to describe the whole process of transmission on each case and to illustrate the relationships between the onset of the disease and the retated factors. RESULTS: Two contact persons appearanced fever and whose throat swabs were tested positive to H1N1 viral nucleic acid. The two had a history of contact in a short distance with the initial imported case without any protective measure in the poor air ventilation. The patients clinical situation was slight. The incubation was between 37 hours and 57 hours. No other new case was found after intervention as isolation and antisepsis were taken. CONCLUSION: This event was proved to be an outbreak of local A/H1N1 secondary cases caused by the imported case. The main mode of transmission was personal contact in a short distance without protection, through air and droplet. The locus with poor air ventilation was high risk place. Contact persons should be observed seven days and tested continuously. Infectivity and pathogenicity of the A/H1N1 virus were limited and appeared weakened by generations. Patient's condition was related with persistence and frequency of contact with the infection sources. Enhancing management of contact persons, health education, early diagnose, early treatment and early insulation were effective measures of controling and prenventing the spread A/H1N1.

[Study on human case of avian influenza in Guangzhou 2006 without causing human-to-human transmission among close contacts].

UNLABELLED: Study on human case of avian influenza in Guangzhou 2006 without causing human-to-human transmission OBJECTIVE: To explore the possibility of transmission from a human case of avian influenza to his close contacts. METHODS: Close contacts of the human case of avian influenza in Guangzhou 2006 were found out according to the definition and methods publicized by the Ministry of Health, People's Republic of China. Epidemiological investigation and medical observation were carried out. Serum antibodies were tested in some of the close contacts. RESULTS: The avian influenza patient had never left Guangzhou in the month prior to disease onset. No contact history with dead or diseased poultry was found. A total of 56 close contacts, including his girl friend, relatives, friends and medical staff who had taken care of him, were brought under medical observation for 7 days but none of them showed signs of infection. CONCLUSION: Unlike SARS, direct contact with patient contracted with avian influenza at the end of incubation period and in the stage of illness through flying droplets, saliva, mucous membrane and skin injuries will not lead to human-to-human transmission, indicating the virus' ability to pass from human to human is limited.

SARS-CoV infection in a restaurant from palm civet.

Epidemiologic investigations showed that 2 of 4 patients with severe acute respiratory syndrome (SARS) identified in the winter of 2003-2004 were a waitresss at a restaurant in Guangzhou, China, that served palm civets as food and a customer who ate in the restaurant ashort distance from animal cages. All 6 palm civets at the restaurant were positive for SARS-associated coronavirus (SARS-CoV). Partial spike (S) gene sequences of SARS-CoV from the 2 patients were identical to 4 of 5 Sgene viral sequences from palm civets. Phylogenetic analysis showed that SARS-CoV from palm civets in the restaurant was most closely related to animal isolates. SARS cases at the restaurant were the result of recent interspecies transfer from the putative palm civet reservoir, and not the result of continued circulation of SARS-CoV in the human population.