Lamb波具有较强的抗干扰能力,被广泛应用于碳纤维增强树脂(Carbon Fiber Reinforced Polymer,CFRP)结构健康监测中。采用汉宁窗形式的窄带Lamb波激励完整CFRP板与含内置损伤的损伤CFRP板,通过比较PZT压电片采集到的健康信号与损伤信号...Lamb波具有较强的抗干扰能力,被广泛应用于碳纤维增强树脂(Carbon Fiber Reinforced Polymer,CFRP)结构健康监测中。采用汉宁窗形式的窄带Lamb波激励完整CFRP板与含内置损伤的损伤CFRP板,通过比较PZT压电片采集到的健康信号与损伤信号之间的信号差异系数,根据改进的损伤概率重建算法(Reconstruction Algorithm for the Probabilistic Inspection of Damage,RAPID)实现CFRP结构的内部损伤成像。得到以下结论:建立CFRP板Lamb波有限元模型对内置损伤的大小和区域进行定位,并根据CFRP板Lamb波结构健康监测试验平台验证有限元模型的正确性;提出一种阈值化改进RAPID算法,对损伤板的内置损伤大小和轮廓进行准确预测,预测结果最大误差仅为6.56%;随着结构内置损伤孔厚度的增加,结构损伤信号与健康信号的差异越发明显,预测损伤参数与实际损伤参数的最小误差仅为5.20 mm。展开更多
Background Dietary protein level and amino acid(AA)balance are crucial determinants of animal health and productivity.Supplementing rumen-protected AAs in low-protein diets was considered as an efficient strategy to i...Background Dietary protein level and amino acid(AA)balance are crucial determinants of animal health and productivity.Supplementing rumen-protected AAs in low-protein diets was considered as an efficient strategy to improve the growth performance of ruminants.The colon serves as a crucial conduit for nutrient metabolism during rumen-protected methionine(RPMet)and rumen-protected lysine(RPLys)supplementation,however,it has been challenging to clarify which specific microbiota and their metabolites play a pivotal role in this process.Here,we applied metagenomic and metabolomic approaches to compare the characteristic microbiome and metabolic strategies in the colon of lambs fed a control diet(CON),a low-protein diet(LP)or a LP diet supplemented with RPMet and RPLys(LR).Results The LP treatment decreased the average daily weight gain(ADG)in lambs,while the LR treatment tended to elicit a remission in ADG.The butyrate molar concentration was greater(P<0.05),while acetate molar concentration(P<0.05)was lower for lambs fed the LP and LR diets compared to those fed the CON diet.Moreover,the LP treatment remarkably decreased total AA concentration(P<0.05),while LR treatment showed an improvement in the concentrations of methionine,lysine,leucine,glutamate,and tryptophan.Metagenomic insights proved that the microbial metabolic potentials referring to biosynthesis of volatile fatty acids(VFAs)and AAs in the colon were remarkably altered by three dietary treatments.Metagenomic binning identified distinct microbial markers for the CON group(Alistipes spp.,Phocaeicola spp.,and Ruminococcus spp.),LP group(Fibrobacter spp.,Prevotella spp.,Ruminococcus spp.,and Escherichia coli),and LR group(Akkermansia muciniphila and RUG099 spp.).Conclusions Our findings suggest that RPMet and RPLys supplementation to the low-protein diet could enhance the microbial biosynthesis of butyrate and amino acids,enriche the beneficial bacteria in the colon,and thereby improve the growth performance of lambs.展开更多
Background Using yeast culture as additives in ruminant feed prevents rumen microbial dysbiosis,enhances performance,and regulates rumen pH.The yeast culture used in this study was developed in-house,and has been show...Background Using yeast culture as additives in ruminant feed prevents rumen microbial dysbiosis,enhances performance,and regulates rumen pH.The yeast culture used in this study was developed in-house,and has been shown to promote rumen epithelial growth in several sheep trials.Changes in protein expression associated with the promotion of rumen epithelial development following the addition of yeast culture,along with the associated molecular mechanisms,remain unknown.We used 2045-day-old weaned lambs to investigate the specific proteins and molecular mechanisms involved in these processes.Half of the lambs were fed yeast culture,and the other half were used as controls.Results Yeast culture enhanced growth performance,facilitated rumen fermentation,and promoted rumen papilla development in weaned lambs.Proteomics data identified 4,831 proteins in the rumen epithelial tissue of lambs,comprising 87 upregulated and 425 downregulated proteins.Administration of yeast culture activated multiple molecular functions within rumen epithelial cells,including oxidative phosphorylation,glutathione metabolism,apoptosis,cell cycle,and vitamin digestion and absorption.The expression of proteins associated with cell cycle regulation increased,whereas those associated with apoptosis decreased.Administration of yeast culture also reduced the duration of the G0/G1 phase of rumen epithelial cells and accelerated the cell cycle.Furthermore,yeast culture showed increased cyclin D1,cyclin-dependent kinase(CDK)2,CDK4,CDK6,and cyclin E1 expressions and decreased cytochrome C(Cyto-c),Bcl-2-related X protein(Bax),cleaved caspase 3(C-caspase 3),caspase 3,and cleaved caspase 7(C-caspase 7)protein expressions.Yeast culture upregulated the insulin-like growth factor-1 receptor(IGF-1R)and insulin-like growth factor-binding protein 5(IGFBP-5)mRNA expressions in rumen epithelial cells.Conclusions Yeast culture facilitates rumen epithelial development by regulating the cell cycle and IGF-1 signaling and reducing the expression of proteins associated with apoptosis in rumen epithelial cells.The findings of this study provide novel insights into the molecular mechanisms through which yeast culture promotes rumen epithelial development in weaned lambs.展开更多
The aim of this study was to investigate the effects of dietary fat on energy and nitrogen(N)metabolism efficiency,rumen fermentation,and microbiota in twin suckling lambs.Thirty pairs of twin male lambs were randomly...The aim of this study was to investigate the effects of dietary fat on energy and nitrogen(N)metabolism efficiency,rumen fermentation,and microbiota in twin suckling lambs.Thirty pairs of twin male lambs were randomly divided into two groups with one group receiving a high-fat diet(HF)and the other a normal-fat diet(NF).Two diets(milk replacer and starter)of equal protein and different fat levels.The metabolism test was conducted when the lambs were 50-60 days old,and nine pairs of twin lambs were randomly selected for slaughter to collect rumen fluid at 60 days old.The result showed that fat addition increased the final body weight(BW),ruminal ammonia nitrogen(NH_(3)-N)content,proportion of propionic acid,and estimated methane production(CH_(4e))(P<0.05).The high fat diet tended to improve digestive energy(DE),metabolism energy(ME),DE/ME,utilisation of N(0.05<P<0.1).However,microbial crude protein(MCP)content,total volatile fatty acids(VFA),acetic acid ratio,and the ratio of acetate to propionate(A:P)were lower than that in the NF group(P<0.05).Regardless of whether fat is added or not,no different were observed in blood metabolites between the treatment.High-throughput sequencing revealed that fat addition before weaning increased phyla Proteobacteria and genera of Succinivibrio,but decreased the relative abundance of Clostridium IV,Dialister,Roseburia,Acidaminococcus,and Megasphaera genera.These findings indicated that high fat diet improved body weight,energy and nitrogen utilization may by shifting the rumen toward propionate fermentation via the enrichment of Succinivibrio.展开更多
In this paper,we theoretically study the Lamb wave in a multilayered piezoelectric semiconductor(PSC)plate,where each layer is an n-type PSC with the symmetry of transverse isotropy.Based on the extended Stroh formali...In this paper,we theoretically study the Lamb wave in a multilayered piezoelectric semiconductor(PSC)plate,where each layer is an n-type PSC with the symmetry of transverse isotropy.Based on the extended Stroh formalism and dual-variable and position(DVP)method,the general solution of the coupled fields for the Lamb wave is derived,and then the dispersion equation is obtained by the application of the boundary conditions.First,the influence of semiconducting properties on the dispersion behavior of the Lamb wave in a single-layer PSC plate is analyzed.Then,the propagation characteristics of the Lamb wave in a sandwich plate are investigated in detail.The numerical results show that the wave speed and attenuation depend on the stacking sequence,layer thickness,and initial carrier density,the Lamb wave can propagate without a cut-off frequency in both the homogeneous and multilayer PSC plates due to the semiconducting properties,and the Lamb wave without attenuation can be achieved by carefully selecting the semiconductor property in the upper and lower layers.These new features could be very helpful as theoretical guidance for the design and performance optimization of PSC devices.展开更多
Ultrasonic Lamb waves undergo complex mode conversion and diffraction at non-penetrating defects, such as plate corrosion and cracks. Lamb wave imaging has a resolution limit due to the guided wave dispersion characte...Ultrasonic Lamb waves undergo complex mode conversion and diffraction at non-penetrating defects, such as plate corrosion and cracks. Lamb wave imaging has a resolution limit due to the guided wave dispersion characteristics and Rayleigh criterion limitations. In this paper, a full convolutional network is designed to segment and reconstruct the received signals, enabling the automatic identification of target modalities. This approach eliminates clutter and mode conversion interference when calculating direct and accompanying acoustic fields in time-domain topological energy(TDTE) imaging.Subsequently, the measured accompanying acoustic field is reversed for adaptive focusing on defects and enhance the imaging quality. To circumvent the limitations of the Rayleigh criterion, the direct acoustic field and the accompanying acoustic field were fused to characterize the pixel distribution in the imaging region, achieving Lamb wave super-resolution imaging. Experimental results indicate that compared to the sign coherence factor-total focusing method(SCF-TFM),the proposed method achieves a 31.41% improvement in lateral resolution and a 29.53% increase in signal-to-noise ratio for single-blind-hole defects. In the case of multiple-blind-hole defects with spacings greater than the Rayleigh criterion resolution limit, it exhibits a 27.23% enhancement in signal-to-noise ratio. On the contrary, when the defect spacings are relatively smaller than the limit, this method has a higher resolution limit than SCF-TFM in super-resolution imaging.展开更多
文摘Lamb波具有较强的抗干扰能力,被广泛应用于碳纤维增强树脂(Carbon Fiber Reinforced Polymer,CFRP)结构健康监测中。采用汉宁窗形式的窄带Lamb波激励完整CFRP板与含内置损伤的损伤CFRP板,通过比较PZT压电片采集到的健康信号与损伤信号之间的信号差异系数,根据改进的损伤概率重建算法(Reconstruction Algorithm for the Probabilistic Inspection of Damage,RAPID)实现CFRP结构的内部损伤成像。得到以下结论:建立CFRP板Lamb波有限元模型对内置损伤的大小和区域进行定位,并根据CFRP板Lamb波结构健康监测试验平台验证有限元模型的正确性;提出一种阈值化改进RAPID算法,对损伤板的内置损伤大小和轮廓进行准确预测,预测结果最大误差仅为6.56%;随着结构内置损伤孔厚度的增加,结构损伤信号与健康信号的差异越发明显,预测损伤参数与实际损伤参数的最小误差仅为5.20 mm。
基金jointly supported by the International Partnership Program of Chinese Academy of Sciences(161343KYSB20200015)Guangxi Provincial Natural Science Foundation of China(2023GXNSFAA026107)+1 种基金the Science and Technology Innovation Program of Hunan Province(2022RC1158)Youth Innovation Promotion Association CAS(2023382)。
文摘Background Dietary protein level and amino acid(AA)balance are crucial determinants of animal health and productivity.Supplementing rumen-protected AAs in low-protein diets was considered as an efficient strategy to improve the growth performance of ruminants.The colon serves as a crucial conduit for nutrient metabolism during rumen-protected methionine(RPMet)and rumen-protected lysine(RPLys)supplementation,however,it has been challenging to clarify which specific microbiota and their metabolites play a pivotal role in this process.Here,we applied metagenomic and metabolomic approaches to compare the characteristic microbiome and metabolic strategies in the colon of lambs fed a control diet(CON),a low-protein diet(LP)or a LP diet supplemented with RPMet and RPLys(LR).Results The LP treatment decreased the average daily weight gain(ADG)in lambs,while the LR treatment tended to elicit a remission in ADG.The butyrate molar concentration was greater(P<0.05),while acetate molar concentration(P<0.05)was lower for lambs fed the LP and LR diets compared to those fed the CON diet.Moreover,the LP treatment remarkably decreased total AA concentration(P<0.05),while LR treatment showed an improvement in the concentrations of methionine,lysine,leucine,glutamate,and tryptophan.Metagenomic insights proved that the microbial metabolic potentials referring to biosynthesis of volatile fatty acids(VFAs)and AAs in the colon were remarkably altered by three dietary treatments.Metagenomic binning identified distinct microbial markers for the CON group(Alistipes spp.,Phocaeicola spp.,and Ruminococcus spp.),LP group(Fibrobacter spp.,Prevotella spp.,Ruminococcus spp.,and Escherichia coli),and LR group(Akkermansia muciniphila and RUG099 spp.).Conclusions Our findings suggest that RPMet and RPLys supplementation to the low-protein diet could enhance the microbial biosynthesis of butyrate and amino acids,enriche the beneficial bacteria in the colon,and thereby improve the growth performance of lambs.
基金supported by the National Key Research and Development Program of China(2023YFE0100400)Science and Technology Project of Inner Mongolia Autonomous Region(2020GG0036)+2 种基金Basic Scientific Research Business Project of Universities directly under the Inner Mongolia Autonomous Region(BR22-11-17)National Center of Technology Innovation for Dairy(2023-JSGG-5)the Special Project for Improving the Research Ability of Young Teachers of Inner Mongolia Agricultural University(BR220133).
文摘Background Using yeast culture as additives in ruminant feed prevents rumen microbial dysbiosis,enhances performance,and regulates rumen pH.The yeast culture used in this study was developed in-house,and has been shown to promote rumen epithelial growth in several sheep trials.Changes in protein expression associated with the promotion of rumen epithelial development following the addition of yeast culture,along with the associated molecular mechanisms,remain unknown.We used 2045-day-old weaned lambs to investigate the specific proteins and molecular mechanisms involved in these processes.Half of the lambs were fed yeast culture,and the other half were used as controls.Results Yeast culture enhanced growth performance,facilitated rumen fermentation,and promoted rumen papilla development in weaned lambs.Proteomics data identified 4,831 proteins in the rumen epithelial tissue of lambs,comprising 87 upregulated and 425 downregulated proteins.Administration of yeast culture activated multiple molecular functions within rumen epithelial cells,including oxidative phosphorylation,glutathione metabolism,apoptosis,cell cycle,and vitamin digestion and absorption.The expression of proteins associated with cell cycle regulation increased,whereas those associated with apoptosis decreased.Administration of yeast culture also reduced the duration of the G0/G1 phase of rumen epithelial cells and accelerated the cell cycle.Furthermore,yeast culture showed increased cyclin D1,cyclin-dependent kinase(CDK)2,CDK4,CDK6,and cyclin E1 expressions and decreased cytochrome C(Cyto-c),Bcl-2-related X protein(Bax),cleaved caspase 3(C-caspase 3),caspase 3,and cleaved caspase 7(C-caspase 7)protein expressions.Yeast culture upregulated the insulin-like growth factor-1 receptor(IGF-1R)and insulin-like growth factor-binding protein 5(IGFBP-5)mRNA expressions in rumen epithelial cells.Conclusions Yeast culture facilitates rumen epithelial development by regulating the cell cycle and IGF-1 signaling and reducing the expression of proteins associated with apoptosis in rumen epithelial cells.The findings of this study provide novel insights into the molecular mechanisms through which yeast culture promotes rumen epithelial development in weaned lambs.
基金supported by China Agriculture Research System of MOF and MARA(CARS-38)。
文摘The aim of this study was to investigate the effects of dietary fat on energy and nitrogen(N)metabolism efficiency,rumen fermentation,and microbiota in twin suckling lambs.Thirty pairs of twin male lambs were randomly divided into two groups with one group receiving a high-fat diet(HF)and the other a normal-fat diet(NF).Two diets(milk replacer and starter)of equal protein and different fat levels.The metabolism test was conducted when the lambs were 50-60 days old,and nine pairs of twin lambs were randomly selected for slaughter to collect rumen fluid at 60 days old.The result showed that fat addition increased the final body weight(BW),ruminal ammonia nitrogen(NH_(3)-N)content,proportion of propionic acid,and estimated methane production(CH_(4e))(P<0.05).The high fat diet tended to improve digestive energy(DE),metabolism energy(ME),DE/ME,utilisation of N(0.05<P<0.1).However,microbial crude protein(MCP)content,total volatile fatty acids(VFA),acetic acid ratio,and the ratio of acetate to propionate(A:P)were lower than that in the NF group(P<0.05).Regardless of whether fat is added or not,no different were observed in blood metabolites between the treatment.High-throughput sequencing revealed that fat addition before weaning increased phyla Proteobacteria and genera of Succinivibrio,but decreased the relative abundance of Clostridium IV,Dialister,Roseburia,Acidaminococcus,and Megasphaera genera.These findings indicated that high fat diet improved body weight,energy and nitrogen utilization may by shifting the rumen toward propionate fermentation via the enrichment of Succinivibrio.
基金Project supported by the National Natural Science Foundation of China(Nos.U21A20430 and 12302202)the Hebei Natural Science Foundation of China(No.A2023210040)+1 种基金the Science and Technology Project of Hebei Education Department of China(No.BJ2025005)the Hebei Provincial Department of Human Resources and Social Security of China(No.C20220324)。
文摘In this paper,we theoretically study the Lamb wave in a multilayered piezoelectric semiconductor(PSC)plate,where each layer is an n-type PSC with the symmetry of transverse isotropy.Based on the extended Stroh formalism and dual-variable and position(DVP)method,the general solution of the coupled fields for the Lamb wave is derived,and then the dispersion equation is obtained by the application of the boundary conditions.First,the influence of semiconducting properties on the dispersion behavior of the Lamb wave in a single-layer PSC plate is analyzed.Then,the propagation characteristics of the Lamb wave in a sandwich plate are investigated in detail.The numerical results show that the wave speed and attenuation depend on the stacking sequence,layer thickness,and initial carrier density,the Lamb wave can propagate without a cut-off frequency in both the homogeneous and multilayer PSC plates due to the semiconducting properties,and the Lamb wave without attenuation can be achieved by carefully selecting the semiconductor property in the upper and lower layers.These new features could be very helpful as theoretical guidance for the design and performance optimization of PSC devices.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12174085)the Key Research and Development Project of Changzhou, Jiangsu Province, China (Grant No. CE20235054)the Postgraduate Research and Practice Innovation Program of Jiangsu Province, China (Grant No. KYCX24 0833)。
文摘Ultrasonic Lamb waves undergo complex mode conversion and diffraction at non-penetrating defects, such as plate corrosion and cracks. Lamb wave imaging has a resolution limit due to the guided wave dispersion characteristics and Rayleigh criterion limitations. In this paper, a full convolutional network is designed to segment and reconstruct the received signals, enabling the automatic identification of target modalities. This approach eliminates clutter and mode conversion interference when calculating direct and accompanying acoustic fields in time-domain topological energy(TDTE) imaging.Subsequently, the measured accompanying acoustic field is reversed for adaptive focusing on defects and enhance the imaging quality. To circumvent the limitations of the Rayleigh criterion, the direct acoustic field and the accompanying acoustic field were fused to characterize the pixel distribution in the imaging region, achieving Lamb wave super-resolution imaging. Experimental results indicate that compared to the sign coherence factor-total focusing method(SCF-TFM),the proposed method achieves a 31.41% improvement in lateral resolution and a 29.53% increase in signal-to-noise ratio for single-blind-hole defects. In the case of multiple-blind-hole defects with spacings greater than the Rayleigh criterion resolution limit, it exhibits a 27.23% enhancement in signal-to-noise ratio. On the contrary, when the defect spacings are relatively smaller than the limit, this method has a higher resolution limit than SCF-TFM in super-resolution imaging.
