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With the development of Internet of Things and intelligence, cleaning mobile robots have gradually replaced the traditional manual cleaning work, and intelligence has become the main research direction of sweeping robots. As a new product in the field of service robot, mopping robot has made some achievements, but there are still many key technical problems to be solved or improved. In order to improve the safety of products in public places such as shopping malls, a robot with multiple cleaning functions such as vacuuming, mopping and drying is proposed. The mechanical mechanisms mainly include a frame, a three wheel walking mechanism, a sweeping mechanism, a mopping mechanism, a drying mechanism, etc. It can realize wifi control and mobile phone APP control, and solve the problems of the existing mopping robot such as single function, low cleaning efficiency, and the danger of slippery ground.

With the increasing application of PVC water supply pipe in production and life, this paper aims at the problem that there is no single sealing ring connected large diameter PVC pipe interface sealing detection equipment in the construction site of agricultural water supply. According to the sealing test method of negative pressure test, a set of large diameter PVC pipe interface sealing test device is designed, and the corresponding test procedures and standards are put forward. The field sealing test of large diameter PVC pipe interface is carried out, and the portable aviation aluminum box with universal wheel is designed and customized. The device has the advantages of simple structure, easy installation and disassembly, easy carrying, and is suitable for field operation. It provides important equipment support for the better promotion and use of large PVC pipes.

In the production process of baking food processing enterprises, cakes, biscuits and other products made by steaming are generally installed in the baking tray and baked in the oven. The temperature of the baking tray is above 100 degrees Celsius when leaving the oven. The high temperature environment is not conducive to the protection of workers. It needs to be left to cool and then be transported, so the production efficiency is low. In order to solve this problem, a method of replacing the manual handling of the baking tray and removing the baked cake product with a turning robot is proposed. At the same time, two methods for improving the design of the cake production line are given, and the structure and use of the two products of the single-column turning manipulator and the articulated turning manipulator are introduced. The single-column turning manipulator consists of a base, a single-column rotating mechanism, a lifting mechanism, a swing arm, a pneumatic gripping mechanism, etc. A frame-type pneumatic gripping mechanism is adopted, and driven by the turning motor, and can realize the turning of the baking tray. The articulated turning manipulator consists of a base, a waist, a big arm, a small arm, a wrist, and a hand actuator. The hand adopts a rotatable square shaft end structure with an electromagnetic device, transforming the cake baking tray to increase the square groove meshed with it, so as to realize the flipping action of the cake baking tray.

The glass curtain wall has good heat preservation and moisture-proof performance and beautiful appearance. It is used as exterior wall decoration in high-rise buildings, its cleaning work is difficult and dangerous. In this paper, the design research of the glass curtain wall cleaning robot is carried out, and a rail-type glass curtain wall cleaning robot is designed, which is mainly composed of a detachable rail and a robot, and is controlled by a 51 microcomputer. The three-dimensional design of the cleaning robot was performed using NX software, and a model prototype was produced. This robot is light in weight and flexible in control. It is suitable for cleaning operations of large glass curtain walls and can reduce the risk factor and labor intensity of cleaning operations.

The plague, which is caused by the Gram-negative coccobacillus bacterium Yersinia pestis, has been classified as a reemerging infectious disease by the World Health Organization. The Qinghai-Tibet Plateau natural plague focus is the largest plague focus in China, and Marmota himalayana is the primary host of the plague. Tibetan sheep (Ovis aries) were first identified as naturally infected hosts of Y. pestis based on etiological evidence in 1975, and activities such as slaughtering or skinning Tibetan sheep that have been infected by Y. pestis or died from Y. pestis infection had caused severe human plague in Qinghai. Tibetan sheep are important domestic livestock in the Qinghai-Tibet Plateau. Knowledge regarding the infection rate of Y. pestis in Tibetan sheep is important for understanding the range of infection and improving measures to control plague epidemics in this area. In this study, a serological survey involving 12,710 Tibetan sheep in all 44 counties in Qinghai Province was conducted. The total positive rate of indirect hemagglutination assay for Y. pestis in Tibetan sheep in Qinghai was 0.68% (86/12,710). Serological positivity to the Y. pestis F1 antibody was found in Tibetan sheep in all prefectures, except the Haidong and Haibei prefectures in Qinghai, with the seropositive rate in different counties ranging from 0.33% to 5.2% and the titers in the positive sera ranging from 1:20 to 1:5120. In addition, the seropositive rates in animal plague focus counties were higher than the rates in non-animal plague counties. Such results indicated a widespread infection of Tibetan sheep with Y. pestis in Qinghai, even though only sporadic epidemics of Tibetan sheep plague have been reported in Qinghai.

This paper describes a dynamic model with four degrees of freedom for simulating the rollover stability performances of articulated loaders. The dynamic model considers three translational degrees of freedom and a rotational degree of freedom about the tilting axis and was verified by field experiments and virtual prototype experiments. The field experiments using a scaled articulated loader are detailed, and the experimental data of the lateral load transfer ratio, the lateral acceleration and the roll angle of the vehicle are provided for classification at different speeds and different turning radii. The virtual prototype experiments are modelled on the experimental model as well as the simulation conditions. Comparing the experimental data with the theoretical data shows that the dynamics model is reasonable and that the virtual prototype simulation can be used instead of the field experiments to improve the security of active safety technology development.

The booming information technology has brought non-negligible and irreversible great influence on our production and life styles, including the education sector. At present, although the teaching mode of culture pedagogy guarantees students’ overall grasp of culture pedagogy, students’ learning for culture pedagogy is not deep enough, and they can neither internalize relevant knowledge nor form the cure quality of culture pedagogy. Besides, the teaching effect is not entirely satisfactory. Thus, the teaching mode which is based on CASH curriculum idea and supported by information technology combines network learning space and utilizes the patent A Method to Achieve Auxiliary Operation in PPT Courseware Playing Process, and the classroom teaching quality evaluation method based on distance comparison were proposed in this study. In addition, the modeling process of network learning space was introduced. The patent A Method to Achieve Auxiliary Operation in PPT Courseware Playing Process, standardized method of distance grade evaluation model, modeling and computer operating system, and teaching case design process of CASH curriculum idea were applied. It was found through the experiment that, students are satisfied with the teaching mode of network learning space based on CASH curriculum idea, and consider that it plays a great role in the learning process, and both the teaching efficiency and teaching quality improve obviously.

A seven-degrees-of-freedom (DOF) dynamic model was established based on the Lagrange equation to analyse the lateral stability and instability mechanism of an articulated wheel loader. A scale wheel loader was designed and manufactured to validate the dynamic model in two conditions, namely turning on slopes and passing over obstacles. Experimental data and simulated data fitted well on the whole, so the developed dynamic model was proved to be useful and could serve as an important tool to analyse the stability of wheel loaders. At last, the lateral stability of one ZL50 wheel loader was analysed by using this dynamic model. The results showed that there is a phenomenon of sudden stability losing during the wheel loader cornering due to the relative rotation between the subframe and the rear axle. The subframe can enhance the stability when the wheel loader is passing over obstacles but reduces the stability when it is turning.

The present paper focuses on the simulation of the non-stationary load histories of engineering vehicles for fatigue tests. For the first time, the characteristics of the service loads experienced by engineering vehicles are described. Then rainflow data-reduction contributing to reduce the testing time and extrapolation of each operating section to generate the unavailable extreme loads in a limit test are carried out. Finally, based on the simulated load history of each operating section using Markov chain Monte Carlo method (MCMC) and the corresponding simulation length generated by the Monte Carlo method, a cyclic simulation approach is proposed to generate non-stationary load histories, by which the cyclic characteristic can be reconstructed well. The results of comparison between the observed and simulated load histories show good agreement.

In this study, a new subunit vaccine that comprised native F1 and recombinant rV270 was evaluated for protective efficacy using mouse, guinea pig and rabbit models in comparison with the live attenuated vaccine EV76. Complete protection against challenging with 10 6 colony-forming units (CFU) of virulent Yersinia pestis strain 141 was observed for mice immunized with the subunit vaccines and EV76 vaccine. In contrast, the subunit vaccine recipes VII (F1-20 μg + rV270-10 μg) and IX (F1-40 μg + rV270-20 μg) and EV76 vaccine provided 86%, 79% and 93% protection against the same level of challenge in guinea pigs and 100%, 83% and 100% protection in rabbits, respectively. The immunized mice with the vaccines had significantly higher IgG titres than the guinea pigs and rabbits, and the immunized guinea pigs developed significantly higher IgG titres than the rabbits, but the anti-F1 response in guinea pigs was more variable than in the mice and rabbits, indicating that guinea pig is not an ideal model for evaluating protective efficacy of plague subunit vaccine, instead the rabbits could be used as an alternative model. All the immunized animals with EV76 developed a negligible IgG titre to rV270 antigen. Furthermore, analysis of IgG subclasses in the immunized animals showed a strong response for IgG1, whereas those receiving EV76 immunization demonstrated predominant production of IgG1 and IgG2a isotypes. The subunit vaccine and EV76 vaccine are able to provide protection for animals against Y. pestis challenge, but the subunit vaccines have obvious advantages over EV76 in terms of safety of use.

Background After the earthquake on 14, April 2010 at Yushu in China, a plague epidemic hosted by Himalayan marmot (Marmota himalayana) became a major public health concern during the reconstruction period. A rapid assessment of the distribution of Himalayan marmot in the area was urgent. The aims of this study were to analyze the relationship between environmental factors and the distribution of burrow systems of the marmot and to predict the distribution of marmots. Methods Two types of marmot burrows (hibernation and temporary) in Yushu County were investigated from June to September in 2011. The location of every burrow was recorded with a global positioning system receiver. An ecological niche model was used to determine the relationship between the burrow occurrence data and environmental variables, such as land surface temperature (LST) in winter and summer, normalized difference vegetation index (NDVI) in winter and summer, elevation, and soil type. The predictive accuracies of the models were assessed by the area under the curve of the receiving operator curve. Results The models for hibernation and temporary burrows both performed well. The contribution orders of the variables were LST in winter and soil type, NDVI in winter and elevation for the hibernation burrow model, and LST in summer, NDVI in summer, soil type and elevation in the temporary burrow model. There were non-linear relationships between the probability of burrow presence and LST, NDVI and elevation. LST of 14 and 23 °C, NDVI of 0.22 and 0.60, and 4100 m were inflection points. A substantially higher probability of burrow presence was observed in swamp soil and dark felty soil than in other soil types. The potential area for hibernation burrows was 5696 km2 (37.7 % of Yushu County), and the area for temporary burrows was 7711 km2 (51.0 % of Yushu County). Conclusions The results suggested that marmots preferred warm areas with relatively low altitudes and good vegetation conditions in Yushu County. Based on these results, the present research is useful in understanding the niche selection and distribution pattern of marmots in this region.

To identify the epidemiology and etiology characteristics of Tibetan sheep plague in Qinghai plateau.The background materials of Qinghai Tibetan sheep plague found during 1975 to 2009 were summarized, the regional, time and interpersonal distribution, infection routes, ecological factors for the spread were used to analyze; followed by choosing 14 Yersinia pestis strains isolated from such sheep for biochemical test, toxicity test, virulence factors identification, plasmid analysis, and DFR genotype.From 1975 to 2009, 14 Yersinia pestis strains were isolated from Tibetan sheep in Qinghai province. Tibetan sheep, as the infection source, had caused 10 cases of human plague, 25 plague patients, and 13 cases of death. All of the initial cases were infected due to eating Tibetan sheep died of plague; followed by cases due to contact of plague patients, while all the initial cases were bubonic plague. Cases of bubonic plague developed into secondary pneumonic plague and septicemia plague were most popular and with high mortality. Most of the Tibetan sheep plague and human plague occurred in Gannan ecological zone in southern Gansu province, which was closely related to its unique ecological and geographical landscape. Tibetan sheep plague coincided with human plague caused by Tibetan sheep, especially noteworthy was that November (a time for marmots to start their dormancy) witnesses the number of Yersinia pestis strains isolated from Tibetan sheep and human plague cases caused by Tibetan sheep. This constituted the underlying cause that the epidemic time of Tibetan sheep plague lags obviously behind that of the Marmot plague. It was confirmed in the study that all the 14 strains were of Qinghai-Tibet Plateau ecotype, with virulence factors evaluation and toxicity test demonstrating strains as velogenic. As found in the (Different Region) DFR genotyping, the strains isolated from Yushu county and Zhiduo county were genomovar 5, the two strain isolated from Nangqian county were genomovar 5 and genomovar 7, while those isolated Delingha region were genomovar 8.Tibetan sheep were vulnerable to plague infection, hence causing human plague as the infectious source. The Yersinia pestis strains isolated from Tibetan sheep plague carried pathogen characteristics of Qinghai-Tibet plateau plague, developing many new characteristics of such plague.

To analyze the results of etiology and serology of plague among human and infected animals in Qinghai province from 2001 to 2010.Thirty-seven cases of human infected with plague, 53 541 different animal samples, 5 685 sets of vector insects flea and 49 039 different animal serum samples were obtained between 2001 and 2010. A total of 7 811 samples of serum from healthy farmers and herdsmen in 14 counties in Qinghai from 2005 to 2007 were collected. Yersinia pestis (Y. pestis) were detected in visceral and secretions from human, infected animals and vector insects, respectively. Plague antigen was detected by reverse indirect hemagglutination assay (RIHA) in those samples. Indirect hemagglutination assay (IHA) was used to test plague FI antibody in serum of human and infected animals.37 human plague cases were confirmed, 21 strains of plague Y. pestis were isolated from human cases and 14 positive were detected out. 133 of 7 811 samples of human serum were IHA positive, with the positive rate at 1.7%. A total of 146 strains of plague were isolated from infected animals and vector insects, 99 out of which were from infected animals, with a ratio of Marmota himalayan at 72.7% (72/99) and the other 47 were from vector insects, with a ratio of callopsylla solaris at 68.1% (32/47). The number of IHA and PIHA positive were 300 and 10, respectively. A total of 3 animals and 3 insects species were identified as new epidemic hosts for plague. The natural plague focus of Microtus fuscus was discovered and confirmed and coexisted with natural focus of Marmota himalayan in Chengduo county, Yushu prefecture. The epidemic situation of plague is distributed mainly in Haixi, Yushu and Hainan prefectures.From 2001 to 2010, animal infected with plague was detected in successive years and human plague was very common in Qinghai. New infected animals and vector insects species and new epidemic areas were confirmed, hence the trend of plague prevalence for humans and animals is very active in Qinghai province.

Artificially passive immunization has been demonstrated to be effective againstYersinia pestisinfection in animals. However, maternal antibodies' protective efficacy against plague has not yet been demonstrated. Here, we evaluated the kinetics, protective efficacy, and transmission modes of maternal antibodies, using mice immunized with plague subunit vaccine SV1 (20 μg of F1 and 10 μg of rV270). The results showed that the rV270- and F1-specific antibodies could be detected in the sera of newborn mice (NM) until 10 and 14 weeks of age, respectively. There was no antibody titer difference between the parturient mice immunized with SV1 (PM-S) and the caesarean-section newborns (CSN) from the PM-S or between the lactating mice immunized by SV1 (LM-S) and the cross-fostered mice (CFM) during 3 weeks of lactation. The NM had a 72% protection against 4,800 CFUY. pestisstrain 141 challenge at 6 weeks of age, whereas at 14 weeks of age, NM all succumbed to 5,700 CFU ofY. pestischallenge. After 7 weeks of age, CFM had an 84% protection against 5,000 CFU ofY. pestischallenge. These results indicated that maternal antibodies induced by the plague subunit vaccine in mother mice can be transferred to NM by both placenta and lactation. Passive antibodies from the immunized mothers could persist for 3 months and provide early protection for NM. The degree of early protection is dependent on levels of the passively acquired antibody. The results indicate that passive immunization should be an effective countermeasure against plague during its epidemics.

Earth-moving machines were always used in the harshest environments, which can decrease operator comfort. The operator seat can reduce the effect of shock and vibration on the operator and provide him with stable support so that he can control the machine effectively. Based on the laboratory evaluation standard and test methods, a set of electro-hydraulic servo operator seat vibration test device and its control system were developed independently in this paper. The system configures WinTest10 all-digital hydraulic servo controller with software system. The software consists of two main parts: Winquick vibration control software and Ranvib random vibration signal processing software. Through the seat vibration test, the seat effective amplitude transmission rate (SEAT) factor and the transmissibility at resonance were obtained. The results provide the basis for the seat vibration-laboratory evaluation. The research indicates that the system is of great significance for the evaluation of operator seat vibration and seat optimization development.

Background. Primarypneumonicplague(PPP)causedbyYersiniapestisisthemostthreateningclinicalformofplague. An outbreak was reported in July 2009 in Qinghai Province, China.Methods. This outbreak was investigated by clinical, epidemiological, bacteriological, and immunologicalmethods. Multilocus variablenumber tandem repeat analysis (MLVA) was used to track the source of the outbreak.Results. The index case, a patient with PPP, contaminated 11 close contacts. All the 12 cases, including theindexpatient, experiencedsuddenonsetof fever, headache,and productivecoughingwithbloody sputum.Threeofthem died. Nevertheless, another 61 direct and 256 indirect contacts were not infected during the 2-weekquarantine. Antibodies to F1 antigen were detected in 9 survival cases, with a 4-fold increase in titers in serumsamples collected at different periods. Seven strains of Y. pestis were isolated from dogs and patients. Fieldinvestigation and MLVA of the isolated strains revealed that this outbreak was started by a deceased dog.Conclusion. Dogs are believed to be an indicator animal for plague surveillance, but their association with PPPis rare. Our results provide evidence for this possibility, which suggests the public health significance of dogs asa source of plague.Plague, caused by Yersinia pestis, was classified asa reemerging infectious disease by the World HealthOrganization (WHO) in the early 1980s, because thereported cases around the world were increasing atthat time. There are different forms of plague, in-cluding bubonic and pneumonic, and the latter is themost threatening clinical form. Primary and second-arypneumonicplagueshavebeenwell-documentedinhistory.Theprimarypneumonicplague(PPP)out-breaks in Oakland in 1919, Los Angeles in 1924 [1],Manchuria during 1910–1911 [2], and Madagascar in1957 are the most frequently cited ones. PPP was alsoreported recently in the United States, India, Uganda,Zambia, Ecuador, and Madagascar [3–11]. BecausePPP progresses so rapidly that the patients often re-ceived a diasgnosis or were suspected to have plagueonly in the late stage of the disease, most of the PPPcases were reported on the basis of retrospectiveepidemiological investigations with only some ofthem confirmed by bacterial isolation and antibodydetection.On29July2009,asuspectedPPPoutbreakinXinghaiCounty, Qinghai provinceof China,was reportedtotheQinghai Ministry of Health by China’s public healthemergency reporting system. The next day, a group ofplague experts, including epidemiologists, bacteriolo-gists, doctors, and management officers, were sentout for further investigation in the Xinghai CountyTibetan (XCT) hospital, where the suspected patientshad been admitted.

In our previous study, complete protection was observed in Chinese-origin rhesus macaques immunized with SV1 (20 µg F1 and 10 µg rV270) and SV2 (200 µg F1 and 100 µg rV270) subunit vaccines and with EV76 live attenuated vaccine against subcutaneous challenge with 6×10(6) CFU of Y. pestis. In the present study, we investigated whether the vaccines can effectively protect immunized animals from any pathologic changes using histological and immunohistochemical techniques. In addition, the glomerular basement membranes (GBMs) of the immunized animals and control animals were checked by electron microscopy. The results show no signs of histopathological lesions in the lungs, livers, kidneys, lymph nodes, spleens and hearts of the immunized animals at Day 14 after the challenge, whereas pathological alterations were seen in the corresponding tissues of the control animals. Giemsa staining, ultrastructural examination, and immunohistochemical staining revealed bacteria in some of the organs of the control animals, whereas no bacterium was observed among the immunized animals. Ultrastructural observation revealed that no glomerular immune deposits on the GBM. These observations suggest that the vaccines can effectively protect animals from any pathologic changes and eliminate Y. pestis from the immunized animals. The control animals died from multi-organ lesions specifically caused by the Y. pestis infection. We also found that subcutaneous infection of animals with Y. pestis results in bubonic plague, followed by pneumonic and septicemic plagues. The histopathologic features of plague in rhesus macaques closely resemble those of rodent and human plagues. Thus, Chinese-origin rhesus macaques serve as useful models in studying Y. pestis pathogenesis, host response and the efficacy of new medical countermeasures against plague.

Objective LcrV is an important component for the development of a subunit vaccine against plague. To reduce immunosuppressive activity of LcrV, a recombinant LcrV variant lacking amino acids 271 to 326 (rV270) was prepared by different methods in this study. Methods A new strategy that produced non-tagged or authentic rV270 protein was designed by insertion of rV270-thrombin-hexahistidine fusion gene into the vector pET24a, or by insertion of hexahistidine-enterokinase-rV270 or hexahistitine-factor Xa-rV270 fusion gene into the vector pET32a. After Co2+ affinity chromatography, a purification strategy was developed by cleavage of His tag on column, following Sephacryl S-200HR column filtration chromatography. Results Removal of His tag by thrombin, enterokinase and factor Xa displayed a yield of 99.5%, 32.4% and 15.3%, respectively. Following Sephacryl S-200HR column filtration chromatography, above 97% purity of rV270 protein was obtained. Purified rV270 that was adsorbed to 25% (v/v) Al(OH)3 adjuvant in phosphate-buffered saline (PBS) induced very high titers of antibody to rV270 in BALB/c mice and protected them (100% survival) against subcutaneous challenge with 106 CFU of Y. pestis virulent strain 141. Conclusion The completely authentic rV270 protein can be prepared by using enterokinase or factor Xa, but they exhibited extremely low cleavage activity to the corresponding recognition site. Thrombin cleavage is an efficient strategy to prepare non-tagged rV270 protein and can be easily operated in a large scale due to its relatively low cost and high cleavage efficacy. The recombinant rV270 can be used as a key component to develop a subunit vaccine of plague.

Long-term protection and antibody response for the subunit vaccine F1-rV270 were determined by using the mouse model. Antibodies to F1 and rV270 were still detectable over a period of 518 days. The complete protection against lethal challenge of Yersinia pestis could be achieved up to day 518 after primary immunization.

F1 antigen is an attractive candidate for the development of a subunit vaccine against plague. In previous study, the extraction of this antigen from Yersinia pestis is characterized by using organic solvents. In this work, a new purification strategy that produced high-purity F1 antigen from Y. pestis EV76 was developed by the substitution of physical disruption for organic solvent one, followed by a combination of ammonium sulfate fractionation and Sephacryl S-200HR column filtration chromatography. As revealed in this study, this purification procedure is simple and effective, and avoids potential adverse effect on the antigen by organic solvents. Highly purified F1 that adsorbed to 25% (v/v) Al(OH) 3 adjuvant in phosphate-buffered saline (PBS) induced very high titers of antibody to F1 in BALB/c mice and protected them (100% survival) against subcutaneous challenge with 10 4 CFU of Y. pestis virulent strain 141.