In this study,newly harvested and aged rice seeds were analyzed to determine their aging process,identify the difference between artificially and naturally aged seeds,and develop a rapid,accurate,and non-destructive d...In this study,newly harvested and aged rice seeds were analyzed to determine their aging process,identify the difference between artificially and naturally aged seeds,and develop a rapid,accurate,and non-destructive detection method for water status and water distribution of rice seed with different vigor.To this end,an artificially accelerated aging test was conducted on the newly harvested rice seeds.Then,low-field nuclear magnetic resonance(LF-NMR)technology was applied to test the new(Shennong No.9816,2018),old(Shennong No.9816,2017),and artificially aged seeds(Shennong No.9816,2018).A standard germination test was conducted for three types of seeds.Finally,the differences of water status and distribution between rice seeds of different vigor were analyzed based on the standard germination test results and wave spectrometry information collected using LF-NMR.The results indicated that new seeds,old seeds,and the artificially accelerated aging rice seeds all exhibited two water phases,and the vigor of rice seeds after the artificial accelerated aging test was lower than that of new seeds.There were significant differences between the frequencies of bound water at the time of the peak and the time at the end of the peak for the three types of seeds.The two times showed an increasing trend for rice seeds with poor vigor,indicating that the ability of the water in the rice seeds having poor vigor to combine with other substances was weakened.There were significant differences between the distributions of free water peak end time for the three types of seeds.All the rice seeds with poor vigor exhibited a decreasing trend at this time,indicating that the freedom of free water inside the rice seed samples with poor vigor was weakened.The total water content of the artificially aged seeds and the aged seeds was higher than that of the new seeds,but the free water content increased from artificially aged seeds to new seeds to aged seeds.This indicates that LF-NMR technology is an effective detection method that can simply compare the differences in seed vitality with respect to water distribution as well as differentiate the seed internal water content of artificially aged and naturally aged seeds.展开更多
The ride vibration of a tractor is affected mostly by the stiffness and damping coefficient of the seat suspension,cabin suspension,cabin rubber mounts,and rubber tires.However,in the case of rubber tractor tires,the ...The ride vibration of a tractor is affected mostly by the stiffness and damping coefficient of the seat suspension,cabin suspension,cabin rubber mounts,and rubber tires.However,in the case of rubber tractor tires,the stiffnesses and damping coefficients have not been researched adequately thus far,and it is not simple to measure these characteristics.In this study,a method for measuring and analyzing the stiffnesses and damping coefficients of rubber tractor tires,which were the input parameters for the tractor ride vibration simulation,was proposed.The cleat test,proposed in this study,did not require separate and complicated test equipment,unlike the conventional methods.The test was conducted simply by measuring acceleration under the driving conditions of the vehicle without detaching tires from the vehicle body or setting up additional test equipment.Based on the ground-vertical acceleration data obtained,the stiffness was calculated using the logarithmic decrement method,and the damping coefficient was calculated using least squares exponential curve fitting.The result of the cleat test indicated that the front tires had stiffnesses of 486.08-570.69 kN/m and damping coefficients of 4.02-4.52 kN·s/m;the rear tires had stiffnesses of 409.42-483.79 kN/m and damping coefficients of 2.21-2.67 kN·s/m.During the test,40 mm height cleats were installed on the track and the speed of the tractor was set to 7 and 10 km/h,which were the most common speeds during the operation.This study is meaningful in that it has presented a new method that improves the practicality of results,reduces cost,and simplifies the test process for measuring the stiffnesses and damping coefficients of rubber tractor tires.展开更多
Hydroxyapatite(HA)is a representative substance that induces bone regeneration.Our research team extracted nanohydroxyapatite(EH)from natural resources,especially equine bones,and developed it as a molecular biologica...Hydroxyapatite(HA)is a representative substance that induces bone regeneration.Our research team extracted nanohydroxyapatite(EH)from natural resources,especially equine bones,and developed it as a molecular biological tool.Polyethylenimine(PEI)was used to coat the EH to develop a gene carrier.To verify that PEI is well coated in the EH,we first observed the morphology and dispersity of PEI-coated EH(pEH)by electron microscopy.The pEH particles were well distributed,while only the EH particles were not distributed and aggregated.Then,the existence of nitrogen elements of PEI on the surface of the pEH was confirmed by EDS,calcium concentration measurement and fourier transform infrared spectroscopy(FT-IR).Additionally,the pEH was confirmed to have a more positive charge than the 25 kD PEI by comparing the zeta potentials.As a result of pGL3 transfection,pEH was better able to transport genes to cells than 25 kD PEI.After verification as a gene carrier for pEH,we induced osteogenic differentiation of DPSCs by loading the BMP-2 gene in pEH(BMP-2/pEH)and delivering it to the cells.As a result,it was confirmed that osteogenic differentiation was promoted by showing that the expression of osteopontin(OPN),osteocalcin(OCN),and runt-related transcription factor 2(RUNX2)was significantly increased in the group treated with BMP-2/pEH.In conclusion,we have not only developed a novel nonviral gene carrier that is better performing and less toxic than 25 kD PEI by modifying natural HA(the agricultural byproduct)but also proved that bone differentiation can be effectively promoted by delivering BMP-2 with pEH to stem cells.展开更多
基金This project was supported by National Natural Science Foundation of China(Grant No.31701318)National Natural Science Foundation of China Projects of International Cooperation and Exchanges(Grant No.31811540396)Basic Research Project of Education Department of Liaoning Province(Grant No.LSNJC201916).
文摘In this study,newly harvested and aged rice seeds were analyzed to determine their aging process,identify the difference between artificially and naturally aged seeds,and develop a rapid,accurate,and non-destructive detection method for water status and water distribution of rice seed with different vigor.To this end,an artificially accelerated aging test was conducted on the newly harvested rice seeds.Then,low-field nuclear magnetic resonance(LF-NMR)technology was applied to test the new(Shennong No.9816,2018),old(Shennong No.9816,2017),and artificially aged seeds(Shennong No.9816,2018).A standard germination test was conducted for three types of seeds.Finally,the differences of water status and distribution between rice seeds of different vigor were analyzed based on the standard germination test results and wave spectrometry information collected using LF-NMR.The results indicated that new seeds,old seeds,and the artificially accelerated aging rice seeds all exhibited two water phases,and the vigor of rice seeds after the artificial accelerated aging test was lower than that of new seeds.There were significant differences between the frequencies of bound water at the time of the peak and the time at the end of the peak for the three types of seeds.The two times showed an increasing trend for rice seeds with poor vigor,indicating that the ability of the water in the rice seeds having poor vigor to combine with other substances was weakened.There were significant differences between the distributions of free water peak end time for the three types of seeds.All the rice seeds with poor vigor exhibited a decreasing trend at this time,indicating that the freedom of free water inside the rice seed samples with poor vigor was weakened.The total water content of the artificially aged seeds and the aged seeds was higher than that of the new seeds,but the free water content increased from artificially aged seeds to new seeds to aged seeds.This indicates that LF-NMR technology is an effective detection method that can simply compare the differences in seed vitality with respect to water distribution as well as differentiate the seed internal water content of artificially aged and naturally aged seeds.
基金This research was supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(Grant No.2019R1F1A1059712).
文摘The ride vibration of a tractor is affected mostly by the stiffness and damping coefficient of the seat suspension,cabin suspension,cabin rubber mounts,and rubber tires.However,in the case of rubber tractor tires,the stiffnesses and damping coefficients have not been researched adequately thus far,and it is not simple to measure these characteristics.In this study,a method for measuring and analyzing the stiffnesses and damping coefficients of rubber tractor tires,which were the input parameters for the tractor ride vibration simulation,was proposed.The cleat test,proposed in this study,did not require separate and complicated test equipment,unlike the conventional methods.The test was conducted simply by measuring acceleration under the driving conditions of the vehicle without detaching tires from the vehicle body or setting up additional test equipment.Based on the ground-vertical acceleration data obtained,the stiffness was calculated using the logarithmic decrement method,and the damping coefficient was calculated using least squares exponential curve fitting.The result of the cleat test indicated that the front tires had stiffnesses of 486.08-570.69 kN/m and damping coefficients of 4.02-4.52 kN·s/m;the rear tires had stiffnesses of 409.42-483.79 kN/m and damping coefficients of 2.21-2.67 kN·s/m.During the test,40 mm height cleats were installed on the track and the speed of the tractor was set to 7 and 10 km/h,which were the most common speeds during the operation.This study is meaningful in that it has presented a new method that improves the practicality of results,reduces cost,and simplifies the test process for measuring the stiffnesses and damping coefficients of rubber tractor tires.
基金This study was supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Science,ICT&Future Planning(NRF-2020R1F1A1067439,NRF-2020R1I1A1A01068262)the Korea Institute of Energy Technology Evaluation and Planning(KETEP)and the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(20194210100230).
文摘Hydroxyapatite(HA)is a representative substance that induces bone regeneration.Our research team extracted nanohydroxyapatite(EH)from natural resources,especially equine bones,and developed it as a molecular biological tool.Polyethylenimine(PEI)was used to coat the EH to develop a gene carrier.To verify that PEI is well coated in the EH,we first observed the morphology and dispersity of PEI-coated EH(pEH)by electron microscopy.The pEH particles were well distributed,while only the EH particles were not distributed and aggregated.Then,the existence of nitrogen elements of PEI on the surface of the pEH was confirmed by EDS,calcium concentration measurement and fourier transform infrared spectroscopy(FT-IR).Additionally,the pEH was confirmed to have a more positive charge than the 25 kD PEI by comparing the zeta potentials.As a result of pGL3 transfection,pEH was better able to transport genes to cells than 25 kD PEI.After verification as a gene carrier for pEH,we induced osteogenic differentiation of DPSCs by loading the BMP-2 gene in pEH(BMP-2/pEH)and delivering it to the cells.As a result,it was confirmed that osteogenic differentiation was promoted by showing that the expression of osteopontin(OPN),osteocalcin(OCN),and runt-related transcription factor 2(RUNX2)was significantly increased in the group treated with BMP-2/pEH.In conclusion,we have not only developed a novel nonviral gene carrier that is better performing and less toxic than 25 kD PEI by modifying natural HA(the agricultural byproduct)but also proved that bone differentiation can be effectively promoted by delivering BMP-2 with pEH to stem cells.
