BACKGROUND:Streptococcus pneumoniae(S.pneumoniae)is a common pathogen that causes bacterial pneumonia.However,with increasing bacterial resistance,there is an urgent need to develop new drugs to treat S.pneumoniae inf...BACKGROUND:Streptococcus pneumoniae(S.pneumoniae)is a common pathogen that causes bacterial pneumonia.However,with increasing bacterial resistance,there is an urgent need to develop new drugs to treat S.pneumoniae infections.Nanodefensin with a 14-carbon saturated fatty acid(ND-C14)is a novel nanoantimicrobial peptide designed by modifying myristic acid at the C-terminus of humanα-defensin 5(HD5)via an amide bond.However,it is unclear whether ND-C14 is effective against lung infections caused by S.pneumoniae.METHODS:In vitro,three groups were established,including the control group,and the HD5 and ND-C14 treatment groups.A virtual colony-count assay was used to evaluate the antibacterial activity of HD5 and ND-C14 against S.pneumoniae.The morphological changes of S.pneumoniae treated with HD5 or ND-C14 were observed by scanning electron microscopy.In vivo,mice were divided into sham,vehicle,and ND-C14 treatment groups.Mice in the sham group were treated with 25μL of phosphate-buffered saline(PBS).Mice in the vehicle and ND-C14 treatment groups were treated with intratracheal instillation of 25μL of bacterial suspension with 2×108 CFU/mL(total bacterial count:5×10^(6) CFU),and then the mice were given 25μL PBS or intratracheally injected with 25μL of ND-C14(including 20μg or 50μg),respectively.Survival rates were evaluated in the vehicle and ND-C14 treatment groups.Bacterial burden in the blood and bronchoalveolar lavage fluid were counted.The lung histology of the mice was assessed.A propidium iodide uptake assay was used to clarify the destructive eff ect of ND-C14 against S.pneumoniae.RESULTS:Compared with HD5,ND-C14 had a better bactericidal eff ect against S.pneumoniae because of its stronger ability to destroy the membrane structure of S.pneumoniae in vitro.In vivo,ND-C14 significantly delayed the death time and improved the survival rate of mice infected with S.pneumoniae.ND-C14 reduced bacterial burden and lung tissue injury.Moreover,ND-C14 had a membrane permeation eff ect on S.pneumoniae,and its destructive ability increased with increasing ND-C14 concentration.CONCLUSION:The ND-C14 may improve bactericidal eff ects on S.pneumoniae both in vitro and in vivo.展开更多
[ Objective] This study aimed to investigate the ehangos of aroma components in mango fruit at different post-harvest stages. [ Method] The aroma com- ponents in ＇ Keitt＇ mango fruit at 3,6, 9 and 13 d postharvest w...[ Objective] This study aimed to investigate the ehangos of aroma components in mango fruit at different post-harvest stages. [ Method] The aroma com- ponents in ＇ Keitt＇ mango fruit at 3,6, 9 and 13 d postharvest were extracted using heM-space solid phase mieroextraction （HS-SPME） and analyzed by gas chre- matograph-rnass speetrephotometer （GC-MS）. [ Result] The results showed that a total of 42 aroma compounds were identified from the mango samples at four sta- ges. To be specific, monoterpene and sesquiterpene were the major components; at 3, 6, 9 and 13 d postharvest, the relative contents of terpene were 94.24%, 98.91%, 55.32% and 95.97%, respectively. [ Conclusion] IS-（ ＋ ）-3-earene is the characteristic aroma component in ripe fruit of ＇ Keitt＇ mango. The aroma of mango fruit is also affected by ester, alcohol and aldehyde compounds.展开更多
Under the background of industrial 4.0, due to the emergence of intelligent factory, end-to-end digital network can better service to create intelligent products, procedures and process, and able to manage complex thi...Under the background of industrial 4.0, due to the emergence of intelligent factory, end-to-end digital network can better service to create intelligent products, procedures and process, and able to manage complex things, and manufacture products more effi ciently. In industrial 4.0 era, people and technology constant interaction becomes possible. People will be the variable instead of constant in the production process. Each producer is likely to provide creative contributions to the fi nal shape of the individualized product, instead of changing mechanically a few innovators design into product. Therefore, exploring the industrial background of applied talents training mode, cultivating real talents to meet the needs of the intelligent technology become the priority of the development of advanced manufacturing technology under the background of industrial 4.0.展开更多
Functionally graded materials(FGMs)can be used els an interlayer.The interlayer connects two homogeneous materials and slows mutations in material properties,owing to the variability of parameters and microstructure.I...Functionally graded materials(FGMs)can be used els an interlayer.The interlayer connects two homogeneous materials and slows mutations in material properties,owing to the variability of parameters and microstructure.In this numerical simulation,a bond-based peridynamic(PD)model was used to perform dynamic fracture analysis of a continuous beam and a sandwiched structure with an FGM interlayer.Some simulation results of two convergence studies,which include grid refinement(m-convergence)and the reducing radius of PD horizon(^-convergence),were discussed.Under a four-point bending load,the propagation behaviors of single pre-crack in the continuous beam with the FGM interlayer at different locations are simulated to compare with the experimental results.For the sandwiched structure,the problems of a single crack and double cracks were considered.The numerical results show that the crack can deflect toward areas where the energy release rate is low.Additionally,the crack on the weak side for symmetric cracks only has fracture behavior,and if the double cracks are asymmetrical,all these cracks have fracture behaviors and propagation of the initial crack in the stiff region has a higher sensitivity than in the compliant region.展开更多
基金supported by the National Natural Science Foundation of China(82072148)Zhejiang Provincial Basic Public Welfare Research Program of Zhejiang Province(LGF21H150002)+1 种基金Zhejiang Medicine and Health Science and Technology Project(2022RC245&2023KY255)Ningbo Municipal Natural Science Foundation(2023J134).
文摘BACKGROUND:Streptococcus pneumoniae(S.pneumoniae)is a common pathogen that causes bacterial pneumonia.However,with increasing bacterial resistance,there is an urgent need to develop new drugs to treat S.pneumoniae infections.Nanodefensin with a 14-carbon saturated fatty acid(ND-C14)is a novel nanoantimicrobial peptide designed by modifying myristic acid at the C-terminus of humanα-defensin 5(HD5)via an amide bond.However,it is unclear whether ND-C14 is effective against lung infections caused by S.pneumoniae.METHODS:In vitro,three groups were established,including the control group,and the HD5 and ND-C14 treatment groups.A virtual colony-count assay was used to evaluate the antibacterial activity of HD5 and ND-C14 against S.pneumoniae.The morphological changes of S.pneumoniae treated with HD5 or ND-C14 were observed by scanning electron microscopy.In vivo,mice were divided into sham,vehicle,and ND-C14 treatment groups.Mice in the sham group were treated with 25μL of phosphate-buffered saline(PBS).Mice in the vehicle and ND-C14 treatment groups were treated with intratracheal instillation of 25μL of bacterial suspension with 2×108 CFU/mL(total bacterial count:5×10^(6) CFU),and then the mice were given 25μL PBS or intratracheally injected with 25μL of ND-C14(including 20μg or 50μg),respectively.Survival rates were evaluated in the vehicle and ND-C14 treatment groups.Bacterial burden in the blood and bronchoalveolar lavage fluid were counted.The lung histology of the mice was assessed.A propidium iodide uptake assay was used to clarify the destructive eff ect of ND-C14 against S.pneumoniae.RESULTS:Compared with HD5,ND-C14 had a better bactericidal eff ect against S.pneumoniae because of its stronger ability to destroy the membrane structure of S.pneumoniae in vitro.In vivo,ND-C14 significantly delayed the death time and improved the survival rate of mice infected with S.pneumoniae.ND-C14 reduced bacterial burden and lung tissue injury.Moreover,ND-C14 had a membrane permeation eff ect on S.pneumoniae,and its destructive ability increased with increasing ND-C14 concentration.CONCLUSION:The ND-C14 may improve bactericidal eff ects on S.pneumoniae both in vitro and in vivo.
基金Supported by Central Nonprofit Basic Scientific Research Project for the Scientific Research Institutes of China(No.1630062012003)
文摘[ Objective] This study aimed to investigate the ehangos of aroma components in mango fruit at different post-harvest stages. [ Method] The aroma com- ponents in ＇ Keitt＇ mango fruit at 3,6, 9 and 13 d postharvest were extracted using heM-space solid phase mieroextraction （HS-SPME） and analyzed by gas chre- matograph-rnass speetrephotometer （GC-MS）. [ Result] The results showed that a total of 42 aroma compounds were identified from the mango samples at four sta- ges. To be specific, monoterpene and sesquiterpene were the major components; at 3, 6, 9 and 13 d postharvest, the relative contents of terpene were 94.24%, 98.91%, 55.32% and 95.97%, respectively. [ Conclusion] IS-（ ＋ ）-3-earene is the characteristic aroma component in ripe fruit of ＇ Keitt＇ mango. The aroma of mango fruit is also affected by ester, alcohol and aldehyde compounds.
文摘Under the background of industrial 4.0, due to the emergence of intelligent factory, end-to-end digital network can better service to create intelligent products, procedures and process, and able to manage complex things, and manufacture products more effi ciently. In industrial 4.0 era, people and technology constant interaction becomes possible. People will be the variable instead of constant in the production process. Each producer is likely to provide creative contributions to the fi nal shape of the individualized product, instead of changing mechanically a few innovators design into product. Therefore, exploring the industrial background of applied talents training mode, cultivating real talents to meet the needs of the intelligent technology become the priority of the development of advanced manufacturing technology under the background of industrial 4.0.
基金the Natural Science Foundation of China(Nos.11872339,11472248)the Natural Science Foundation of Henan Province(No.182300410221).
文摘Functionally graded materials(FGMs)can be used els an interlayer.The interlayer connects two homogeneous materials and slows mutations in material properties,owing to the variability of parameters and microstructure.In this numerical simulation,a bond-based peridynamic(PD)model was used to perform dynamic fracture analysis of a continuous beam and a sandwiched structure with an FGM interlayer.Some simulation results of two convergence studies,which include grid refinement(m-convergence)and the reducing radius of PD horizon(^-convergence),were discussed.Under a four-point bending load,the propagation behaviors of single pre-crack in the continuous beam with the FGM interlayer at different locations are simulated to compare with the experimental results.For the sandwiched structure,the problems of a single crack and double cracks were considered.The numerical results show that the crack can deflect toward areas where the energy release rate is low.Additionally,the crack on the weak side for symmetric cracks only has fracture behavior,and if the double cracks are asymmetrical,all these cracks have fracture behaviors and propagation of the initial crack in the stiff region has a higher sensitivity than in the compliant region.
