Mangrove forests in southern Iran are of high ecological and economic importance.These forests are being threatened because of uncontrolled harvesting to provide fodder for livestock.The objective of this study is to ...Mangrove forests in southern Iran are of high ecological and economic importance.These forests are being threatened because of uncontrolled harvesting to provide fodder for livestock.The objective of this study is to provide recommendations for appropriate harvesting intensities by quantifying the effect of different harvesting intensities on vegetative and vigor characteristics of mangrove trees.This study was conducted using a randomized complete block design comprising four treatments(10.00%,20.00%,and 30.00% trimming,along with a control)replicated three times.Vegetative characteristics were measured before and after trimming(five-year period)and analyzed using generalized linear model statistical analysis.The growths of the average diameter of canopy,canopy area,canopy volume,canopy height,tree height,and collar diameter in the control treatment were all significantly higher than those in the trimming treatments.In addition,there was a decreasing trend in leaf fresh and dry mass,leaf area index,total area of canopy leaves,and health status of tree in the trimming treatments.For example,the percentage change in fresh and dry leaf mass in the control treatment was positive(29.87% and 38.31%,respectively),whereas the trimming treatments of 10.00%,20.00% and 30.00% had negative effects(-7.01% and -4.79%,-11.32% and -14.30%,and -15.84% and -17.29%,respectively).In addition,the changes in leaf area index in the control(4.95%)and 30.00% trimming(-24.57%)treatments were the highest and lowest,respectively.The percentage change in soil organic matter in the control,10.00%,20.00%,and 30.00% treatments were 22.94%,-9.90%,-16.91%,and -18.68%,respectively.The study demonstrated that gray mangrove trees were highly sensitive to canopy trimming,with even minimal trimming intensities negatively affecting vegetative growth and soil organic matter.Therefore,it is recommended that cutting and trimming of mangrove trees should be prevented even at low intensity to preserve mangrove ecosystem health and resilience against environmental stressors.展开更多
In order to effectively remove the residual Ge atoms at the surface of channel and improve the interfacial characteristic of gate-all-around(GAA)Si nanosheet field effect transistors,a low-temperature atomic-level tri...In order to effectively remove the residual Ge atoms at the surface of channel and improve the interfacial characteristic of gate-all-around(GAA)Si nanosheet field effect transistors,a low-temperature atomic-level trimming approach using ammonia peroxide water mixture(APM)solution treatment followed by diluted hydrofluoric acid is proposed and carried out.The capacitor samples with SiGe epitaxy layer,similar thermal budget and channel release process were fabricated using advanced high-k/metal-gate.An 83%reduction in surface roughness at atomic level is obtained by increasing APM treatment time.Moreover,there are 99.45% reduction in the interface state density(D_(it))and 96.8%leakage reduction in current density(J_(g))after APM treatment,indicating a promising method for future GAA NSFET performance optimization.展开更多
The mechanical balance process is the key process to eliminate the quadrature error and improve the performance of the cupped wave gyro. The conventional mechanical balance method for cupped wave gyro based on cup-wal...The mechanical balance process is the key process to eliminate the quadrature error and improve the performance of the cupped wave gyro. The conventional mechanical balance method for cupped wave gyro based on cup-wall trimming requires high control accuracy of trimming quantity, which increases the production cost and decreases the fabrication efficiency in large extent. However, it is hard to reach the high balance accuracy with the natural frequency split of mHz grade by using the conventional method. In this paper, the lumped mass dynamic model of the cupped wave gyro is built by discretization method, and the effects of different position trimming on the natural frequency are analyzed. It is pointed out that trimming off a tiny quantity of material from cup-wall causes large variation of the natural frequency is the main reason for the low accuracy of the conventional mechanical balance method. Then, a precision balance method for cupped wave gyro based on cup-bottom trimming is presented and the entire procedures of this method are given. The static balance process and dynamic balance process of the precision balance method are simulated by the finite element software. The simulation result shows that the precision balance method based on cup-bottom trimming brings less additional natural frequency split in the static balance process, minimizes the natural frequency split to mHz grade and rectify the angle of mode offset to 0.1° grade in the dynamic balance process, furthermore, the method decreases the requirement for control accuracy of trimming quantity evidently. The research work provides references for structure optimization design and balance process plan of the cupped wave gyro.展开更多
Airborne pulse Doppler radar is a key threat to the military helicopter,and assessing the stealth performance of helicopter against airborne early warning radar is helpful to the helicopter’s stealth design and opera...Airborne pulse Doppler radar is a key threat to the military helicopter,and assessing the stealth performance of helicopter against airborne early warning radar is helpful to the helicopter’s stealth design and operational planning.In this paper,the Shooting and Bouncing Ray(SBR)and Uniform Theory of Diffraction(UTD)based high-frequency algorithms are used to calculate the Radar Cross Section(RCS)of helicopter,and the radar range equations are used to evaluate the stealth performance.In order to account for the effects of rotor flapping motions during actual flight,the aerodynamics model of whole helicopter is established and the attitudes and controls of helicopter at different flight states are trimmed and input into the RCS calculation module.The effects of helicopter flight speed,flying direction and operational environment on radar stealth performance are studied in focus.It is demonstrated by the results that the trimming control does have a great influence of more than 5 dB on the RCS of helicopter,and the introduction of the trim calculation brings the helicopter’s returns calculation closer to the reality.Variations in flight speed lead to the changes in the stealth performance of helicopter against Early Warning Aircraft(EWA),and the helicopter flight speed can be planned according to the operational requirements to minimize exposure distance or exposure time.Variations in flying direction mainly affect the detection properties of helicopter returns,and flying in the same direction with EWA usually gives the helicopter better low-observability than flying head-on.Variations in operational environment mainly affect the radar detection performance and the sensitivity of the detection performance to external factors;the same amount of change in some external factor causes a different amount of change in the helicopter’s detectability in different environments.展开更多
In this paper, we introduce a z-axis quartz gyroscope using a double-H tuning fork, which has a high sensitivity. However, it also causes a large mechanical quadrature error. The laser trimming method is used to suppr...In this paper, we introduce a z-axis quartz gyroscope using a double-H tuning fork, which has a high sensitivity. However, it also causes a large mechanical quadrature error. The laser trimming method is used to suppress this error at quartz level. The trimming law is obtained through the finite element method （FEM）. A femtosecond laser processing system is used to trim the gold balancing masses on the beams, and experimental results are basically consistent with the simulated ones. The mechanical quadrature error is suppressed by 96%, from 26.3° s-1 to 1.1° s-1. Nonlinearity changes from 1.48% to 0.30%, angular random walk （ARW） is reduced from 2.19° h-1/2 to 1.42° h-1/2, and bias instability is improved by a factor of 7.7, from 197.6° h-1 to 25.4° h-1.展开更多
Based on the elastic-plastic large deformation finite element formulation as well as the shell element combined discrete Kirchhoff theoretical plate element (DKT) with membrane square element, deep-drawing bending spr...Based on the elastic-plastic large deformation finite element formulation as well as the shell element combined discrete Kirchhoff theoretical plate element (DKT) with membrane square element, deep-drawing bending springback of typical U-pattern is studied. At the same time the springback values of the drawing of patterns' unloading and trimming about the satellite aerial reflecting surface are predicted and also compared with those of the practical punch. Above two springbacks all obtain satisfactory results, which provide a kind of effective quantitative pre-prediction of springback for the practical engineers.展开更多
AIM:To evaluate the efficacy and safety of endoscopic removal and trimming of self-expandable metallic stents(SEMS).METHODS:All SEMS had been placed for distal biliary strictures.Twenty-seven endoscopic procedures wer...AIM:To evaluate the efficacy and safety of endoscopic removal and trimming of self-expandable metallic stents(SEMS).METHODS:All SEMS had been placed for distal biliary strictures.Twenty-seven endoscopic procedures were performed in 19 patients in whom SEMS(one uncovered and 18 covered) removal had been attempted,and 8 patients in whom stent trimming using argon plasma coagulation(APC) had been attempted at Tokyo Medical University Hospital.The APC settings were:voltage 60-80 W and gas flow at 1.5 L/min.RESULTS:The mean stent indwelling period for all patients in whom stent removal had been attempted was 113.7 ± 77.6 d(range,8-280 d).Of the 19 patients in whom removal of the SEMS had been attempted,the procedure was successful in 14(73.7%) without procedure-related adverse events.The indwelling period in the stent removable group was shorter than that in the unremovable group(94.9 ± 71.5 d vs 166.2 ± 76.2 d,P = 0.08).Stent trimming was successful for all patients with one minor adverse event consisting of self-limited hemorrhage.Trimming time ranged from 11 to 16 min.CONCLUSION:Although further investigations on larger numbers of cases are necessary to accumulate evidence,the present data suggested that stent removal and stent trimming is feasible and effective for stent-related complications.展开更多
Beak trimming was a part of routine husbandry for poultry industry,which was the most efficient and economic way to reduce the incidence of cannibalism.However,the controversy about young chicken trimming still exits ...Beak trimming was a part of routine husbandry for poultry industry,which was the most efficient and economic way to reduce the incidence of cannibalism.However,the controversy about young chicken trimming still exits and it was drawing more concern recently along with the popular of animal behavior and welfare theory.To evaluate the influence of beak trimming on young chicken spleen development and find the key regulators of the spleen development,in this study,the electron microscope technique,flow cytometry and immunohistochemical techniques were used to investigate the effects of beak trimming stress on the spleen development.The result of electronic microscope showed that significant stress response could be found in chicken spleen cells after beak trimming.Cell volume became larger,chromatin of cell nuclear agglutinated conglobation,cytoplasm formed more vacuole,and mitochondria emerged vacuolization phenomenon in splenic lymphocyte after beak trimming.From the flow cytometry,the lymphocyte of spleen in the control group and experimental group were mainly in G1 phase,and the remaining small amount was in S and M phases.Of interest,the number of the lymphocyte which are in G1 phase within immune organ in the experimental group were more than that in the control group,but the number of cells in S and M phases were less than that in the control group.And beak trimming decreased the lymphocytes proliferation index of spleen.Inmmuohistochemical result showed that the beak trimming stress did not affect the expression sites of two apoptosis-related genes,Bcl-2 and Bax,in the spleen.But the expression level of Bcl-2 decreased while Bax increased in chicken immune organs after beak trimming.Furthermore,the beak trimming increased spleen cell apoptosis with a time-dependant style.Our findings may make a contribution to the active precaution of stress response.展开更多
This study proposes a novel tool wear model for the edge trimming process of carbon fiber-reinforced plasticities(CFRPs).The main innovation is that the model considers the actual wear state of both the planar flank f...This study proposes a novel tool wear model for the edge trimming process of carbon fiber-reinforced plasticities(CFRPs).The main innovation is that the model considers the actual wear state of both the planar flank face and the semicylindrical cutting edge.In addition,for the whole wear process,the model illustrates the dynamic wear condition by introducing a varying wear coefficient determined by the instantaneous force‒temperature condition and relative movement distance.The analytical results of the tool wear law suggest that cutting edge wear depends on tool nose rigidity and the practical contact distance with the CFRP workpiece mainly.To suppress cutting edge wear,reducing the rake angle and flank angle to improve rigidity and selecting a low spindle speed and high feed rate to decrease the practical cutting distance are recommended.The wear of the flank face is mainly determined by the flank angle and bouncing back height of the machined surface.To reduce its wear,a large flank angle,high spindle speed,and low feed rate are recommended.Since the strategies for reducing the wear of the cutting edge and flank faces are contradictory,to reduce tool wear more effectively,reducing cutting-edge wear is prioritized.展开更多
This study presents a scheme for the identification and trimming of the first three harmonics of mass defects in micro hemispherical resonators(MHRs),aiming to refine their mass balancing techniques.Given the manufact...This study presents a scheme for the identification and trimming of the first three harmonics of mass defects in micro hemispherical resonators(MHRs),aiming to refine their mass balancing techniques.Given the manufacturing and structural uniqueness of MHRs,a multimodal elastic electrode substrate is designed to respond to the first three harmonics.Configured as cantilever beams with a load platform,this substrate forms an identification assembly with the MHR.The radial eccentric forces generated by the 1st and 3rd harmonics in the MHR can excite the swing modes of the assembly,while the axial force generated by the 2nd harmonic can induce axial mode vibrations along the Z-axis.A method is proposed to decompose the vibration information of the elastic electrode substrate into doublecycle,single-cycle,and offset components under the N=2 modes,enabling the extraction of swing mode and Z-axis translational mode response signals and the retro-calculation of the first three harmonics.Finite element simulation,based on a model of the identification assembly,validates the proposed scheme by simulating the identification and trimming process.Subsequently,an identification assembly sample is fabricated and subjected to identification and trimming of the first three harmonics using a laser vibrometer and femtosecond laser ablation process.After multiple iterations,the first three harmonics are reduced by 92.8%,89.3%,and 75.5%,respectively,effectively suppressing the swing modes and axial translation modes induced by unbalanced mass.展开更多
Alzheimer's disease is characterized by deposition of amyloid-β,which forms extracellular neuritic plaques,and accumulation of hyperphosphorylated tau,which aggregates to form intraneuronal neurofibrillary tangle...Alzheimer's disease is characterized by deposition of amyloid-β,which forms extracellular neuritic plaques,and accumulation of hyperphosphorylated tau,which aggregates to form intraneuronal neurofibrillary tangles,in the brain.The NLRP3 inflammasome may play a role in the transition from amyloid-βdeposition to tau phosphorylation and aggregation.Because NLRP3 is primarily found in brain microglia,and tau is predominantly located in neurons,it has been suggested that NLRP3 expressed by microglia indirectly triggers tau phosphorylation by upregulating the expression of pro-inflammatory cytokines.Here,we found that neurons also express NLRP3 in vitro and in vivo,and that neuronal NLRP3 regulates tau phosphorylation.Using biochemical methods,we mapped the minimal NLRP3 promoter and identified FUBP3 as a transcription factor regulating NLRP3 expression in neurons.In primary neurons and the neuroblastoma cell line Neuro2A,FUBP3 is required for endogenous NLRP3 expression and tau phosphorylation only when amyloid-βis present.In the brains of aged wild-type mice and a mouse model of Alzheimer's disease,FUBP3 expression was markedly increased in cortical neurons.Transcriptome analysis suggested that FUBP3 plays a role in neuron-mediated immune responses.We also found that FUBP3 trimmed the 5′end of DNA fragments that it bound,implying that FUBP3 functions in stress-induced responses.These findings suggest that neuronal NLRP3 may be more directly involved in the amyloid-β-to–phospho-tau transition than microglial NLRP3,and that amyloid-βfundamentally alters the regulatory mechanism of NLRP3 expression in neurons.Given that FUBP3 was only expressed at low levels in young wild-type mice and was strongly upregulated in the brains of aged mice and Alzheimer's disease mice,FUBP3 could be a safe therapeutic target for preventing Alzheimer's disease progression.展开更多
目的:探讨三结构域蛋白家族24(tripartite motif-containing protein 24,TRIM24)、c-myc及ARF蛋白在食管鳞状细胞癌组织中的表达及其意义。方法:选取2018年01月至2022年12月期间承德市中心医院接受手术治疗的102例食管鳞癌患者临床病理...目的:探讨三结构域蛋白家族24(tripartite motif-containing protein 24,TRIM24)、c-myc及ARF蛋白在食管鳞状细胞癌组织中的表达及其意义。方法:选取2018年01月至2022年12月期间承德市中心医院接受手术治疗的102例食管鳞癌患者临床病理资料作为研究对象(实验组),同时选取癌旁正常食管黏膜组织54例(对照组),采用免疫组化(Envision法)对TRIM24、c-myc及ARF蛋白进行检测,观察三者在鳞癌组织及癌旁正常食管黏膜组织中的表达情况,并分析三者的表达与临床病理特征的关系,同时研究三者于食管鳞癌组织内表达的相关性。结果:TRIM24、c-myc及ARF在鳞癌组织及癌旁正常食管黏膜组织中阳性表达率分别为72.62%vs 7.45%、74.36%vs 13.85%、26.56%vs 83.18%,三种蛋白在鳞癌组织及正常食管黏膜组织中的表达差异具有统计学意义(P均<0.05);经分析,食管鳞癌组织中的TRIM24、c-myc及ARF蛋白表达与癌的分化程度、淋巴结转移、临床分期具有显著相关性(P均<0.05);经Spearman相关性分析,食管鳞癌组织中TRIM24与c-myc蛋白表达呈正相关(r=0.587,P<0.05),TRIM24与ARF蛋白表达呈负相关(r=-0.601,P<0.05),c-myc与ARF蛋白表达呈负相关(r=-0.465,P<0.05)。结论:TRIM24、c-myc、ARF的异常表达可能对食管鳞状细胞癌的发生及发展有一定关系。因此,c-myc、TRIM24和ARF可能作为新的潜在治疗靶点,为食管鳞癌患者的个体化治疗提供新的方向。展开更多
文摘Mangrove forests in southern Iran are of high ecological and economic importance.These forests are being threatened because of uncontrolled harvesting to provide fodder for livestock.The objective of this study is to provide recommendations for appropriate harvesting intensities by quantifying the effect of different harvesting intensities on vegetative and vigor characteristics of mangrove trees.This study was conducted using a randomized complete block design comprising four treatments(10.00%,20.00%,and 30.00% trimming,along with a control)replicated three times.Vegetative characteristics were measured before and after trimming(five-year period)and analyzed using generalized linear model statistical analysis.The growths of the average diameter of canopy,canopy area,canopy volume,canopy height,tree height,and collar diameter in the control treatment were all significantly higher than those in the trimming treatments.In addition,there was a decreasing trend in leaf fresh and dry mass,leaf area index,total area of canopy leaves,and health status of tree in the trimming treatments.For example,the percentage change in fresh and dry leaf mass in the control treatment was positive(29.87% and 38.31%,respectively),whereas the trimming treatments of 10.00%,20.00% and 30.00% had negative effects(-7.01% and -4.79%,-11.32% and -14.30%,and -15.84% and -17.29%,respectively).In addition,the changes in leaf area index in the control(4.95%)and 30.00% trimming(-24.57%)treatments were the highest and lowest,respectively.The percentage change in soil organic matter in the control,10.00%,20.00%,and 30.00% treatments were 22.94%,-9.90%,-16.91%,and -18.68%,respectively.The study demonstrated that gray mangrove trees were highly sensitive to canopy trimming,with even minimal trimming intensities negatively affecting vegetative growth and soil organic matter.Therefore,it is recommended that cutting and trimming of mangrove trees should be prevented even at low intensity to preserve mangrove ecosystem health and resilience against environmental stressors.
基金financially supported by the Strategic Pilot Project of the Chinese Academy of Sciences-Class A(No.XDA0330302)the National Natural Science Foundation of China(Nos.62374183 and 62304247)the 2021 Jilin Province Science and Technology Department Key R&D Projects(No.20210201031GX)。
文摘In order to effectively remove the residual Ge atoms at the surface of channel and improve the interfacial characteristic of gate-all-around(GAA)Si nanosheet field effect transistors,a low-temperature atomic-level trimming approach using ammonia peroxide water mixture(APM)solution treatment followed by diluted hydrofluoric acid is proposed and carried out.The capacitor samples with SiGe epitaxy layer,similar thermal budget and channel release process were fabricated using advanced high-k/metal-gate.An 83%reduction in surface roughness at atomic level is obtained by increasing APM treatment time.Moreover,there are 99.45% reduction in the interface state density(D_(it))and 96.8%leakage reduction in current density(J_(g))after APM treatment,indicating a promising method for future GAA NSFET performance optimization.
基金supported by National Natural Science Foundation of China (Grant No. 51005239)
文摘The mechanical balance process is the key process to eliminate the quadrature error and improve the performance of the cupped wave gyro. The conventional mechanical balance method for cupped wave gyro based on cup-wall trimming requires high control accuracy of trimming quantity, which increases the production cost and decreases the fabrication efficiency in large extent. However, it is hard to reach the high balance accuracy with the natural frequency split of mHz grade by using the conventional method. In this paper, the lumped mass dynamic model of the cupped wave gyro is built by discretization method, and the effects of different position trimming on the natural frequency are analyzed. It is pointed out that trimming off a tiny quantity of material from cup-wall causes large variation of the natural frequency is the main reason for the low accuracy of the conventional mechanical balance method. Then, a precision balance method for cupped wave gyro based on cup-bottom trimming is presented and the entire procedures of this method are given. The static balance process and dynamic balance process of the precision balance method are simulated by the finite element software. The simulation result shows that the precision balance method based on cup-bottom trimming brings less additional natural frequency split in the static balance process, minimizes the natural frequency split to mHz grade and rectify the angle of mode offset to 0.1° grade in the dynamic balance process, furthermore, the method decreases the requirement for control accuracy of trimming quantity evidently. The research work provides references for structure optimization design and balance process plan of the cupped wave gyro.
基金supported by a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD).
文摘Airborne pulse Doppler radar is a key threat to the military helicopter,and assessing the stealth performance of helicopter against airborne early warning radar is helpful to the helicopter’s stealth design and operational planning.In this paper,the Shooting and Bouncing Ray(SBR)and Uniform Theory of Diffraction(UTD)based high-frequency algorithms are used to calculate the Radar Cross Section(RCS)of helicopter,and the radar range equations are used to evaluate the stealth performance.In order to account for the effects of rotor flapping motions during actual flight,the aerodynamics model of whole helicopter is established and the attitudes and controls of helicopter at different flight states are trimmed and input into the RCS calculation module.The effects of helicopter flight speed,flying direction and operational environment on radar stealth performance are studied in focus.It is demonstrated by the results that the trimming control does have a great influence of more than 5 dB on the RCS of helicopter,and the introduction of the trim calculation brings the helicopter’s returns calculation closer to the reality.Variations in flight speed lead to the changes in the stealth performance of helicopter against Early Warning Aircraft(EWA),and the helicopter flight speed can be planned according to the operational requirements to minimize exposure distance or exposure time.Variations in flying direction mainly affect the detection properties of helicopter returns,and flying in the same direction with EWA usually gives the helicopter better low-observability than flying head-on.Variations in operational environment mainly affect the radar detection performance and the sensitivity of the detection performance to external factors;the same amount of change in some external factor causes a different amount of change in the helicopter’s detectability in different environments.
基金Project supported by the National Natural Science Foundation of China(Grant No.61027007)
文摘In this paper, we introduce a z-axis quartz gyroscope using a double-H tuning fork, which has a high sensitivity. However, it also causes a large mechanical quadrature error. The laser trimming method is used to suppress this error at quartz level. The trimming law is obtained through the finite element method （FEM）. A femtosecond laser processing system is used to trim the gold balancing masses on the beams, and experimental results are basically consistent with the simulated ones. The mechanical quadrature error is suppressed by 96%, from 26.3° s-1 to 1.1° s-1. Nonlinearity changes from 1.48% to 0.30%, angular random walk （ARW） is reduced from 2.19° h-1/2 to 1.42° h-1/2, and bias instability is improved by a factor of 7.7, from 197.6° h-1 to 25.4° h-1.
基金This project is supported by National Natural Science Foundation of China (No.19832020)Provincial Natural Science Foundation of Jilin (No.20000519)
文摘Based on the elastic-plastic large deformation finite element formulation as well as the shell element combined discrete Kirchhoff theoretical plate element (DKT) with membrane square element, deep-drawing bending springback of typical U-pattern is studied. At the same time the springback values of the drawing of patterns' unloading and trimming about the satellite aerial reflecting surface are predicted and also compared with those of the practical punch. Above two springbacks all obtain satisfactory results, which provide a kind of effective quantitative pre-prediction of springback for the practical engineers.
文摘AIM:To evaluate the efficacy and safety of endoscopic removal and trimming of self-expandable metallic stents(SEMS).METHODS:All SEMS had been placed for distal biliary strictures.Twenty-seven endoscopic procedures were performed in 19 patients in whom SEMS(one uncovered and 18 covered) removal had been attempted,and 8 patients in whom stent trimming using argon plasma coagulation(APC) had been attempted at Tokyo Medical University Hospital.The APC settings were:voltage 60-80 W and gas flow at 1.5 L/min.RESULTS:The mean stent indwelling period for all patients in whom stent removal had been attempted was 113.7 ± 77.6 d(range,8-280 d).Of the 19 patients in whom removal of the SEMS had been attempted,the procedure was successful in 14(73.7%) without procedure-related adverse events.The indwelling period in the stent removable group was shorter than that in the unremovable group(94.9 ± 71.5 d vs 166.2 ± 76.2 d,P = 0.08).Stent trimming was successful for all patients with one minor adverse event consisting of self-limited hemorrhage.Trimming time ranged from 11 to 16 min.CONCLUSION:Although further investigations on larger numbers of cases are necessary to accumulate evidence,the present data suggested that stent removal and stent trimming is feasible and effective for stent-related complications.
基金supported by the National Natural Science Foundation of China(31072023)the National Agricultural Science and Technology Achievements Transformation Foundation of China(2009GB2D000218)as well as the Earmarked Fund for Modern Agro-Industry Technology Research System,China(CARS-41-K04)
文摘Beak trimming was a part of routine husbandry for poultry industry,which was the most efficient and economic way to reduce the incidence of cannibalism.However,the controversy about young chicken trimming still exits and it was drawing more concern recently along with the popular of animal behavior and welfare theory.To evaluate the influence of beak trimming on young chicken spleen development and find the key regulators of the spleen development,in this study,the electron microscope technique,flow cytometry and immunohistochemical techniques were used to investigate the effects of beak trimming stress on the spleen development.The result of electronic microscope showed that significant stress response could be found in chicken spleen cells after beak trimming.Cell volume became larger,chromatin of cell nuclear agglutinated conglobation,cytoplasm formed more vacuole,and mitochondria emerged vacuolization phenomenon in splenic lymphocyte after beak trimming.From the flow cytometry,the lymphocyte of spleen in the control group and experimental group were mainly in G1 phase,and the remaining small amount was in S and M phases.Of interest,the number of the lymphocyte which are in G1 phase within immune organ in the experimental group were more than that in the control group,but the number of cells in S and M phases were less than that in the control group.And beak trimming decreased the lymphocytes proliferation index of spleen.Inmmuohistochemical result showed that the beak trimming stress did not affect the expression sites of two apoptosis-related genes,Bcl-2 and Bax,in the spleen.But the expression level of Bcl-2 decreased while Bax increased in chicken immune organs after beak trimming.Furthermore,the beak trimming increased spleen cell apoptosis with a time-dependant style.Our findings may make a contribution to the active precaution of stress response.
基金supported by the National Natural Science Foundation for Young Scholars of China(No.52005077)the Natural Science Foundation of Liaoning Province(No.2022-BS090)the Fundamental Research Funds for the Central Universities(No.DUT23RC(3)010).
文摘This study proposes a novel tool wear model for the edge trimming process of carbon fiber-reinforced plasticities(CFRPs).The main innovation is that the model considers the actual wear state of both the planar flank face and the semicylindrical cutting edge.In addition,for the whole wear process,the model illustrates the dynamic wear condition by introducing a varying wear coefficient determined by the instantaneous force‒temperature condition and relative movement distance.The analytical results of the tool wear law suggest that cutting edge wear depends on tool nose rigidity and the practical contact distance with the CFRP workpiece mainly.To suppress cutting edge wear,reducing the rake angle and flank angle to improve rigidity and selecting a low spindle speed and high feed rate to decrease the practical cutting distance are recommended.The wear of the flank face is mainly determined by the flank angle and bouncing back height of the machined surface.To reduce its wear,a large flank angle,high spindle speed,and low feed rate are recommended.Since the strategies for reducing the wear of the cutting edge and flank faces are contradictory,to reduce tool wear more effectively,reducing cutting-edge wear is prioritized.
基金supported by the National Natural Science Foundation of China(62204261,51935013 and 52075540).
文摘This study presents a scheme for the identification and trimming of the first three harmonics of mass defects in micro hemispherical resonators(MHRs),aiming to refine their mass balancing techniques.Given the manufacturing and structural uniqueness of MHRs,a multimodal elastic electrode substrate is designed to respond to the first three harmonics.Configured as cantilever beams with a load platform,this substrate forms an identification assembly with the MHR.The radial eccentric forces generated by the 1st and 3rd harmonics in the MHR can excite the swing modes of the assembly,while the axial force generated by the 2nd harmonic can induce axial mode vibrations along the Z-axis.A method is proposed to decompose the vibration information of the elastic electrode substrate into doublecycle,single-cycle,and offset components under the N=2 modes,enabling the extraction of swing mode and Z-axis translational mode response signals and the retro-calculation of the first three harmonics.Finite element simulation,based on a model of the identification assembly,validates the proposed scheme by simulating the identification and trimming process.Subsequently,an identification assembly sample is fabricated and subjected to identification and trimming of the first three harmonics using a laser vibrometer and femtosecond laser ablation process.After multiple iterations,the first three harmonics are reduced by 92.8%,89.3%,and 75.5%,respectively,effectively suppressing the swing modes and axial translation modes induced by unbalanced mass.
基金supported by a grant from Key Laboratory of Alzheimer's Disease of Zhejiang Province,Institute of Aging,Wenzhou Medical University,No.ZJAD-2021002(to ZW)。
文摘Alzheimer's disease is characterized by deposition of amyloid-β,which forms extracellular neuritic plaques,and accumulation of hyperphosphorylated tau,which aggregates to form intraneuronal neurofibrillary tangles,in the brain.The NLRP3 inflammasome may play a role in the transition from amyloid-βdeposition to tau phosphorylation and aggregation.Because NLRP3 is primarily found in brain microglia,and tau is predominantly located in neurons,it has been suggested that NLRP3 expressed by microglia indirectly triggers tau phosphorylation by upregulating the expression of pro-inflammatory cytokines.Here,we found that neurons also express NLRP3 in vitro and in vivo,and that neuronal NLRP3 regulates tau phosphorylation.Using biochemical methods,we mapped the minimal NLRP3 promoter and identified FUBP3 as a transcription factor regulating NLRP3 expression in neurons.In primary neurons and the neuroblastoma cell line Neuro2A,FUBP3 is required for endogenous NLRP3 expression and tau phosphorylation only when amyloid-βis present.In the brains of aged wild-type mice and a mouse model of Alzheimer's disease,FUBP3 expression was markedly increased in cortical neurons.Transcriptome analysis suggested that FUBP3 plays a role in neuron-mediated immune responses.We also found that FUBP3 trimmed the 5′end of DNA fragments that it bound,implying that FUBP3 functions in stress-induced responses.These findings suggest that neuronal NLRP3 may be more directly involved in the amyloid-β-to–phospho-tau transition than microglial NLRP3,and that amyloid-βfundamentally alters the regulatory mechanism of NLRP3 expression in neurons.Given that FUBP3 was only expressed at low levels in young wild-type mice and was strongly upregulated in the brains of aged mice and Alzheimer's disease mice,FUBP3 could be a safe therapeutic target for preventing Alzheimer's disease progression.
