Background： Dietary nucleotides, considered as antibiotics alternative, were shown to have positive effects on intestinal hyperaemia, systemic immunity, small-intestinal growth, and hepatic composition in pigs. Howev...Background： Dietary nucleotides, considered as antibiotics alternative, were shown to have positive effects on intestinal hyperaemia, systemic immunity, small-intestinal growth, and hepatic composition in pigs. However, there is no previous research on nucleotide supplementation in weanling pigs under an oral challenged E. coil K88. Therefore, 2 experiments were conducted to investigate the effects of dietary nucleotides on weanling pig growth performance, nutrient digestibility, fecal score, and blood profile after being orally challenged with E. coli K88. Methods： In Exp. 1, a total of 140 weanling pigs [8.33 ± 0.33 kg of body weight （BW）, 28-d old] were used in this 42-d feeding trial. Pigs were distributed into 1 of 4 treatments, 5 pigs/pen （3 barrows and 2 gilts） and 7 pens/treatment. Treatments were a control basal diet （CON） or the CON supplemented with 150 （R150）, 220 （R220）, or 275 （R275） mg/kg to give the three treatment diets. In Exp. 2, 28 weanling pigs （BW = 8.40 ± 0.22 kg, 28-d old） were distributed into 1 of 4 treatments to give 1 pig/pen and 7 pens/treatment in a 42-d feeding and challenge trial. Dietary treatments were the same as in Exp. 1. 0n d 14, all those pigs （BW= 13.3±0.15 kg, 42-d old） were orally dosed with 1.5 mL suspension containing 10 cfu/mL of E. coli K88. Twenty four hours after challenge, blood and excreta samples were collected from each pigs for analysis. Fecal scores were measured on d 7, 14, 21, and 28 of the study. Results： In Exp. 1, overall BW, average daily gain （ADG）, gain/feed （G/F） ratio, and nutrient digestibilities were lower （P 〈 0.05） in CON group compared with the nucleotides fed pigs. In Exp. 2, after challenge, IgA, IgM, and IGF-I were higher （P〈 0.05） in the nucleotide groups compared with CON. However, the nucleotide groups had lower （P 〈 0.05） cortisol and TNF-o compared with CON. Fecal E. coil counts and fecal score for the nucleotide groups were lower （P 〈 0.05） than for CON. Conclusions： In conclusion, dietary nucleotides supplementation could improve growth performance, nutrient digestibility, immune status, microbial balance, reduce diarrhea, and provide protection against enterotoxigenic E. coli K88 infection in weanling pigs.展开更多
Automated control and calibration are important components in industrial process and in artificial intelligence system and robotics.In order to solve the problem of contact high-temperature strain precision measuremen...Automated control and calibration are important components in industrial process and in artificial intelligence system and robotics.In order to solve the problem of contact high-temperature strain precision measurement,this paper established an automatic calibration device for high-temperature strain gauges.The temperature of the high-temperature furnace is automatically controlled by the temperature control device.The electric cylinder is driven by the servo motor to apply the load to the calibration beam.The output signal of the high-temperature strain gauge,the thermocouple signal,and the displacement signal of the grating ruler are collected at the same time.The deformation measurement results obtained after temperature correction are used to calculate the theoretical mechanical strain,which are fed back to control the loading action to complete the automatic calibration process.Based on the above calibration device,the hightemperature strain measurement accuracy correction software is developed to calibrate the high-temperature strain gauge with multiparameters,and the curves of sensitivity coefficient,thermal output,zero drift,and creep characteristics with temperature are obtained,and a strain measurement accuracy compensation model is established.The high-temperature strain measurement experiment is carried out to verify that the modified model can meet the requirements in each temperature range.展开更多
Chemokines are cytokines that can promote the activation and migration of immune cells,and increase the recognition of antigen by antigen-presenting cells(APC).Previous studies showed that a DNA vaccine can induce hum...Chemokines are cytokines that can promote the activation and migration of immune cells,and increase the recognition of antigen by antigen-presenting cells(APC).Previous studies showed that a DNA vaccine can induce humoral and cellular immune responses of flounder after immunization.To explore the improvement of chemokines on the efficiency of OmpK vaccine,two bicistronic DNA candidate vaccines were constructed and the immune responses they induced in the flounder were investigated by reverse transcription polymerase chain reaction(RT-PCR),indirect immunofl uorescent assay(IFA),H&E staining,fl ow cytometry(FCM),and quantifi cational real-time polymerase chain reaction(qRT-PCR).pBudCE4.1 plasmid as an expression vector,bicistronic DNA vaccines encoding OmpK gene and CC-motif ligand 4 gene(p-OmpK-CCL4),or Ompk gene and CC-motif ligand 19 gene(p-OmpK-CCL19)were successfully constructed.The results showed that two bicistronic DNA vaccines expressed Ompk protein of Vibrio anguillarum and CCL4/CCL19 proteins of fl ounder both in vitro and in vivo.After immunization,a large number of leucocytes in muscle were recruited at the injection site in treatment groups.The constructed vaccines induced signifi cant increases in CD4-1^(+) and CD4-2^(+) T lymphocytes,and sIgM^(+) B lymphocytes in peripheral blood,spleen,and head kidney.The percentage of T lymphocytes peaked on the 14^(th) post-vaccination day whereas that of B lymphocytes peaked in the 6^(th) post-vaccination week.Moreover,the expression profi les of 10 immune-related genes increased in muscles around the injection site,spleen,and head kidney.After the challenge,p-OmpK-CCL4 and p-OmpK-CCL19 conferred a relative percentage survival(RPS)of 74.1%and 63.3%,respectively,higher than p-OmpK alone(40.8%).In conclusion,both CCL4 and CCL19 can improve the protection of p-OmpK via evoking local immune response and then humoral and cellular immunity.CCL4 and CCL19 will be potential molecular adjuvants for use in DNA vaccines.展开更多
To study the deterioration mechanisms of anhydrite rock under the freeze-thaw weathering process,the physico-mechanical characteristics and microstructure evolutions of anhydrite samples were determined by a series of...To study the deterioration mechanisms of anhydrite rock under the freeze-thaw weathering process,the physico-mechanical characteristics and microstructure evolutions of anhydrite samples were determined by a series of laboratory tests.Then,a descriptive-behavioral model was used to measure the integrity loss in anhydrite samples caused by cyclic freeze-thaw.Finally,the freeze-thaw damage mechanisms of anhydrite rock were revealed from the macro and micro aspects.The results show that the pore size of the anhydrite rock is mainly concentrated in the range of 0.001-10μm.As the number of freeze-thaw cycles increases,there is a growth in the proportion of macropores and mesopores.However,the proportion of micropores shows a declining trend.The relations of the uniaxial compressive strength,triaxial compressive strength,cohesion,and elastic modulus versus freeze-thaw cycles can be fitted by a decreasing exponential function,while the internal friction angle is basically unchanged with freezethaw cycles.With the increase of confining pressure,the disintegration rates of the compressive strength and the elastic modulus decrease,and the corresponding half-life values increase,which reveals that the increase of confining pressures could inhibit freeze-thaw damage to rocks.Moreover,it has been proven that the water chemical softening mechanism plays an essential role in the freeze-thaw damage to anhydrite rock.Furtherly,it is concluded that the freeze-thaw weathering process significantly influences the macroscopic and microscopic damages of anhydrite rock.展开更多
The integrated on-board battery chargers (IOBCs) can be used to repurpose the existing high-rated power electronic devices in electric vehicles (EVs) for charging, thereby cutting costs. However, non-isolated IOBCs fa...The integrated on-board battery chargers (IOBCs) can be used to repurpose the existing high-rated power electronic devices in electric vehicles (EVs) for charging, thereby cutting costs. However, non-isolated IOBCs face significant common-mode (CM) leakage currents owing to the lack of current isolation and coupling between the AC and DC side CM filters. A method that combines topology and modulation to suppress the CM leakage currents in a non-isolated integrated charger is proposed. The touch current can be suppressed below a reaction threshold of 1 MIU. This enhancement enables the safe usage and commercialization of transformer-less chargers, presenting superior charger efficiency, power density, and cost-effectiveness. The CM model of the proposed system is derived to guide the design of the circuit topology and modulation schemes. The simulation results are used to determine the feasibility of these techniques. Finally, a prototype of the 6.6 kW experimental charger is proposed, and the experimental results demonstrate the effectiveness of the proposed solution.展开更多
基金supported by Department of Animal Resource & Science,Dankook University
文摘Background： Dietary nucleotides, considered as antibiotics alternative, were shown to have positive effects on intestinal hyperaemia, systemic immunity, small-intestinal growth, and hepatic composition in pigs. However, there is no previous research on nucleotide supplementation in weanling pigs under an oral challenged E. coil K88. Therefore, 2 experiments were conducted to investigate the effects of dietary nucleotides on weanling pig growth performance, nutrient digestibility, fecal score, and blood profile after being orally challenged with E. coli K88. Methods： In Exp. 1, a total of 140 weanling pigs [8.33 ± 0.33 kg of body weight （BW）, 28-d old] were used in this 42-d feeding trial. Pigs were distributed into 1 of 4 treatments, 5 pigs/pen （3 barrows and 2 gilts） and 7 pens/treatment. Treatments were a control basal diet （CON） or the CON supplemented with 150 （R150）, 220 （R220）, or 275 （R275） mg/kg to give the three treatment diets. In Exp. 2, 28 weanling pigs （BW = 8.40 ± 0.22 kg, 28-d old） were distributed into 1 of 4 treatments to give 1 pig/pen and 7 pens/treatment in a 42-d feeding and challenge trial. Dietary treatments were the same as in Exp. 1. 0n d 14, all those pigs （BW= 13.3±0.15 kg, 42-d old） were orally dosed with 1.5 mL suspension containing 10 cfu/mL of E. coli K88. Twenty four hours after challenge, blood and excreta samples were collected from each pigs for analysis. Fecal scores were measured on d 7, 14, 21, and 28 of the study. Results： In Exp. 1, overall BW, average daily gain （ADG）, gain/feed （G/F） ratio, and nutrient digestibilities were lower （P 〈 0.05） in CON group compared with the nucleotides fed pigs. In Exp. 2, after challenge, IgA, IgM, and IGF-I were higher （P〈 0.05） in the nucleotide groups compared with CON. However, the nucleotide groups had lower （P 〈 0.05） cortisol and TNF-o compared with CON. Fecal E. coil counts and fecal score for the nucleotide groups were lower （P 〈 0.05） than for CON. Conclusions： In conclusion, dietary nucleotides supplementation could improve growth performance, nutrient digestibility, immune status, microbial balance, reduce diarrhea, and provide protection against enterotoxigenic E. coli K88 infection in weanling pigs.
文摘Automated control and calibration are important components in industrial process and in artificial intelligence system and robotics.In order to solve the problem of contact high-temperature strain precision measurement,this paper established an automatic calibration device for high-temperature strain gauges.The temperature of the high-temperature furnace is automatically controlled by the temperature control device.The electric cylinder is driven by the servo motor to apply the load to the calibration beam.The output signal of the high-temperature strain gauge,the thermocouple signal,and the displacement signal of the grating ruler are collected at the same time.The deformation measurement results obtained after temperature correction are used to calculate the theoretical mechanical strain,which are fed back to control the loading action to complete the automatic calibration process.Based on the above calibration device,the hightemperature strain measurement accuracy correction software is developed to calibrate the high-temperature strain gauge with multiparameters,and the curves of sensitivity coefficient,thermal output,zero drift,and creep characteristics with temperature are obtained,and a strain measurement accuracy compensation model is established.The high-temperature strain measurement experiment is carried out to verify that the modified model can meet the requirements in each temperature range.
基金Supported by the National Natural Science Foundation of China(Nos.32173005,31730101,31672684)the National Key Research and Development Program of China(No.2018YFD0900503)+5 种基金the Shandong Provincial Natural Science Foundation(No.ZR2020KC025)the Fundamental Research Funds for the Central Universities(No.201822015)the Director Foundation of Functional Laboratory for Marine Fisheries Science and Food Production Processes,Qingdao National Laboratory for Marine Science and Technology(No.2018MFSD-01)the NBRPC(No.2012CB114406)the Key Research and Development Program of Shandong Province(No.2016GNC115001)the Taishan Scholar Program of Shandong Province。
文摘Chemokines are cytokines that can promote the activation and migration of immune cells,and increase the recognition of antigen by antigen-presenting cells(APC).Previous studies showed that a DNA vaccine can induce humoral and cellular immune responses of flounder after immunization.To explore the improvement of chemokines on the efficiency of OmpK vaccine,two bicistronic DNA candidate vaccines were constructed and the immune responses they induced in the flounder were investigated by reverse transcription polymerase chain reaction(RT-PCR),indirect immunofl uorescent assay(IFA),H&E staining,fl ow cytometry(FCM),and quantifi cational real-time polymerase chain reaction(qRT-PCR).pBudCE4.1 plasmid as an expression vector,bicistronic DNA vaccines encoding OmpK gene and CC-motif ligand 4 gene(p-OmpK-CCL4),or Ompk gene and CC-motif ligand 19 gene(p-OmpK-CCL19)were successfully constructed.The results showed that two bicistronic DNA vaccines expressed Ompk protein of Vibrio anguillarum and CCL4/CCL19 proteins of fl ounder both in vitro and in vivo.After immunization,a large number of leucocytes in muscle were recruited at the injection site in treatment groups.The constructed vaccines induced signifi cant increases in CD4-1^(+) and CD4-2^(+) T lymphocytes,and sIgM^(+) B lymphocytes in peripheral blood,spleen,and head kidney.The percentage of T lymphocytes peaked on the 14^(th) post-vaccination day whereas that of B lymphocytes peaked in the 6^(th) post-vaccination week.Moreover,the expression profi les of 10 immune-related genes increased in muscles around the injection site,spleen,and head kidney.After the challenge,p-OmpK-CCL4 and p-OmpK-CCL19 conferred a relative percentage survival(RPS)of 74.1%and 63.3%,respectively,higher than p-OmpK alone(40.8%).In conclusion,both CCL4 and CCL19 can improve the protection of p-OmpK via evoking local immune response and then humoral and cellular immunity.CCL4 and CCL19 will be potential molecular adjuvants for use in DNA vaccines.
基金the National Natural Science Foundation of China for financial support (Grant No. 51578091)
文摘To study the deterioration mechanisms of anhydrite rock under the freeze-thaw weathering process,the physico-mechanical characteristics and microstructure evolutions of anhydrite samples were determined by a series of laboratory tests.Then,a descriptive-behavioral model was used to measure the integrity loss in anhydrite samples caused by cyclic freeze-thaw.Finally,the freeze-thaw damage mechanisms of anhydrite rock were revealed from the macro and micro aspects.The results show that the pore size of the anhydrite rock is mainly concentrated in the range of 0.001-10μm.As the number of freeze-thaw cycles increases,there is a growth in the proportion of macropores and mesopores.However,the proportion of micropores shows a declining trend.The relations of the uniaxial compressive strength,triaxial compressive strength,cohesion,and elastic modulus versus freeze-thaw cycles can be fitted by a decreasing exponential function,while the internal friction angle is basically unchanged with freezethaw cycles.With the increase of confining pressure,the disintegration rates of the compressive strength and the elastic modulus decrease,and the corresponding half-life values increase,which reveals that the increase of confining pressures could inhibit freeze-thaw damage to rocks.Moreover,it has been proven that the water chemical softening mechanism plays an essential role in the freeze-thaw damage to anhydrite rock.Furtherly,it is concluded that the freeze-thaw weathering process significantly influences the macroscopic and microscopic damages of anhydrite rock.
文摘The integrated on-board battery chargers (IOBCs) can be used to repurpose the existing high-rated power electronic devices in electric vehicles (EVs) for charging, thereby cutting costs. However, non-isolated IOBCs face significant common-mode (CM) leakage currents owing to the lack of current isolation and coupling between the AC and DC side CM filters. A method that combines topology and modulation to suppress the CM leakage currents in a non-isolated integrated charger is proposed. The touch current can be suppressed below a reaction threshold of 1 MIU. This enhancement enables the safe usage and commercialization of transformer-less chargers, presenting superior charger efficiency, power density, and cost-effectiveness. The CM model of the proposed system is derived to guide the design of the circuit topology and modulation schemes. The simulation results are used to determine the feasibility of these techniques. Finally, a prototype of the 6.6 kW experimental charger is proposed, and the experimental results demonstrate the effectiveness of the proposed solution.
