Bone wound healing is a highly dynamic and precisely controlled process through which damaged bone undergoes repair and complete regeneration. External factors can alter this process, leading to delayed or failed bone...Bone wound healing is a highly dynamic and precisely controlled process through which damaged bone undergoes repair and complete regeneration. External factors can alter this process, leading to delayed or failed bone wound healing. The findings of recent studies suggest that the use of selective serotonin reuptake inhibitors(SSRIs) can reduce bone mass, precipitate osteoporotic fractures and increase the rate of dental implant failure. With 10% of Americans prescribed antidepressants, the potential of SSRIs to impair bone healing may adversely affect millions of patients’ ability to heal after sustaining trauma. Here, we investigate the effect of the SSRI sertraline on bone healing through pre-treatment with(10 mg·kg-1sertraline in drinking water, n = 26) or without(control, n = 30) SSRI followed by the creation of a 5-mm calvarial defect. Animals were randomized into three surgical groups:(a) empty/sham,(b) implanted with a DermaMatrix scaffold soak-loaded with sterile PBS or(c) DermaMatrix soak-loaded with542.5 ng BMP2. SSRI exposure continued until sacrifice in the exposed groups at 4 weeks after surgery. Sertraline exposure resulted in decreased bone healing with significant decreases in trabecular thickness, trabecular number and osteoclast dysfunction while significantly increasing mature collagen fiber formation. These findings indicate that sertraline exposure can impair bone wound healing through disruption of bone repair and regeneration while promoting or defaulting to scar formation within the defect site.展开更多
In integrated circuits, the defects associated with photolithography are assumed to be in the shape of circular discs in order to perform the estimation of yield and fault analysis. However,real defects exhibit a grea...In integrated circuits, the defects associated with photolithography are assumed to be in the shape of circular discs in order to perform the estimation of yield and fault analysis. However,real defects exhibit a great variety of shapes. In this paper,a novel yield model is presented and the critical area model of short circuit is correspondingly provided. In comparison with the circular model corrently available, the new model takes the similarity shape to an original defect, the two-dimensional distributional characteristic of defects, the feature of a layout routing and the character of yield estimation into account. As for the aspect of prediction of yield, the experimental results show that the new model may predict the yield caused by real defects more accurately than the circular model does. It is significant that the yield is accurately estimated and improved using the proposed model.展开更多
Studies on ZnO ceramic varistors by deep heat treatment at 650–900 C are reported. The current creep time curve exhibits a peak during the continuous action of a dc biasing voltage; the forwardV-l characteristic is i...Studies on ZnO ceramic varistors by deep heat treatment at 650–900 C are reported. The current creep time curve exhibits a peak during the continuous action of a dc biasing voltage; the forwardV-l characteristic is improved rather than degraded after the action of the biasing voltage. We assume that the zinc interstitial cations Zni are out diffused rapidly and the concentration of Zni in the depletion layer is decreased rapidly during deep heat treatment; the oxygen anions O’o could be accumulated at the grain interface if the out diffusion quantity of Zni is not enough to react with the O’o; the current creep phenomenon above results from the migration of the interface O’o by the biasing voltage. We suggest an improved grain boundary defect model for the ZnO varistors by deep heat treatment, and examine the model using the experimental data of lifetime positron-annihilation spectroscopy.展开更多
The biomechanical relationship between the articular cartilage defect and knee osteoarthritis (OA) has not been clearly defined. This study presents a 3D knee finite element model (FEM) to determine the effect of cart...The biomechanical relationship between the articular cartilage defect and knee osteoarthritis (OA) has not been clearly defined. This study presents a 3D knee finite element model (FEM) to determine the effect of cartilage defects on the stress distribution around the defect rim. The complete knee FEM, which includes bones, articular cartilages, menisci and ligaments, is developed from computed tomography and magnetic resonance images. This FEM then is validated and used to simulate femoral cartilage defects. Based on the obtained results, it is confirmed that the 3D knee FEM is reconstructed with high-fidelity level and can faithfully predict the knee contact behavior. Cartilage defects drastically affect the stress distribution on articular cartilages. When the defect size was smaller than 1.00cm2, the stress elevation and redistribution were found undistinguishable. However, significant stress elevation and redistribution were detected due to the large defect sizes ( 1.00cm2). This alteration of stress distribution has important implications relating to the progression of cartilage defect to OA in the human knee joint.展开更多
The importance of software residual defects and some prediction residual defects models are introduced. The problem that is not easy adapted to a general model is discussed. The model of prediction residual defects ba...The importance of software residual defects and some prediction residual defects models are introduced. The problem that is not easy adapted to a general model is discussed. The model of prediction residual defects based on BBNs is proposed and the detailed processes of the approach are given.展开更多
The pile, as an important foundation style, is being used in engineering practice. Defects of different types and damages of different degrees easily occur during the process of pile construction. So, dietecting defec...The pile, as an important foundation style, is being used in engineering practice. Defects of different types and damages of different degrees easily occur during the process of pile construction. So, dietecting defects of the pile is very important. As so far, there are some difficult problems in pile defect detection. Based on stress wave theory, some of these typical difficult problems were studied through model tests. The analyses of the test results are carried out and some significant results of the low-strain method are obtained, when a pile has a gradually-decreasing crosssection part, the amplitude of the reflective signal originating from the defect is dependent on the decreasing value of the rate of crosssection β. No apparent signal reflected from the necking appeares on the velocity response curve when the value of β is less than about 3. 5 %.展开更多
Contaminated surfaces of the feedstock materials in aluminum alloy casting processes often produce various types of defects which can affect the tensile properties of the final products as well as their fatigue reliab...Contaminated surfaces of the feedstock materials in aluminum alloy casting processes often produce various types of defects which can affect the tensile properties of the final products as well as their fatigue reliabilities.Semi-solid processing takes advantage of a much higher apparent viscosity of the die cast materials by limiting the risk of oxides formed at the free surfaces to become incorporated into the casting when the material is injected into the die.Most of existing semi-solid processes that use billets as feedstock material are however tied up with a different type of contaminated surface.During the injection phase,the external-skin on the periphery of the billet,which has been in contact with air and lubricant during the transfer in the shot sleeve,can be incorporated into the casting.When subjected to a heat treatment,the lubricant is decomposed and produces lens shape porosities.This might be a cause of reject for most structural parts.To avoid this kind of defects,the paths along which the billet skin evolves must be controlled during filling.In order to investigate the possibility of skin inclusion into cast parts during injection of the billet,a two-phase finite element mixture model is employed to model the metal flow.The formation of a skin on the periphery of the billet is modeled by setting an initial solid phase concentration profile in the radial direction.Microscopic observations of the real castings show that the approach is able to model the shear layers and to predict the paths along which the"lens porosity"defects could be formed.An Arbitrary Eulerian-Lagangian(ALE) method is also investigated and appears to be very promising to follow the skin movement in the casting.展开更多
The shrinkage defect of a ductile iron casting is attributed to the volume variations occurring in solidification, which consist of liquid contraction, solidification shrinkage, graphitization expansion, and mold cavi...The shrinkage defect of a ductile iron casting is attributed to the volume variations occurring in solidification, which consist of liquid contraction, solidification shrinkage, graphitization expansion, and mold cavity enlargement. Based on this understanding, a mathematical model for predicting the shrinkage defect of the casting is developed, in which the volume variations of the casting in soli- dification are numerically simulated, especially, the mold cavity enlargement is quantitatively calculated. Moreover, the reliability of the model is verified in production and experiment.展开更多
针对目前金属表面缺陷检测面临模型参数量大、精确度不足、工业现场部署困难等问题,提出了一种基于YOLOv8(you only look once version 8)的轻量化金属表面缺陷检测改进模型。该模型通过引入SCconv(spatial and channel reconst-ruction...针对目前金属表面缺陷检测面临模型参数量大、精确度不足、工业现场部署困难等问题,提出了一种基于YOLOv8(you only look once version 8)的轻量化金属表面缺陷检测改进模型。该模型通过引入SCconv(spatial and channel reconst-ruction convolution)模块、C2f_Dual模块和倒残差多尺度注意力机制iEMA(inverted residual and efficient multi-scale attention),有效降低了模型参数量和计算量,同时提高了检测精度。实验使用SDI-YOLO在NEU-DET、Magnetic-Tile-Defect数据集上验证,mAP50分别比YOLOv8提高了2.5%、2.6%,参数量降低了15.6%,运算量减少了10.9%。与领域主流算法相比,SDI-YOLO在检测精度和参数量方面都有一定的优势,满足边缘设备部署中参数量较小、识别率高等需求。SDI-YOLO模型为金属表面缺陷检测提供了一种高效、轻量化的解决方案,具有重要的实际应用价值。展开更多
基金supported by a grant from the Musculoskeletal Transplant Foundation (JC)the National Institute of Health, the National Institute of Aging [NIH-NIA PO1-AG036675] (ME, WDH)+4 种基金in part by the Department of Veterans Affairs (VA Merit Award BX000333, ACL 1I01CX000930-01, WDH)funded through a training grant from the National Institutes of Health National Institute of Dental and Craniofacial Research [5T32DE017551]S.H. is funded through a fellowship from the National Institutes of Health National Institute of Dental and Craniofacial Research [5F32DE02471202]supported by the National Institutes of Health National Institute of General Medicine [P30GM103331]
文摘Bone wound healing is a highly dynamic and precisely controlled process through which damaged bone undergoes repair and complete regeneration. External factors can alter this process, leading to delayed or failed bone wound healing. The findings of recent studies suggest that the use of selective serotonin reuptake inhibitors(SSRIs) can reduce bone mass, precipitate osteoporotic fractures and increase the rate of dental implant failure. With 10% of Americans prescribed antidepressants, the potential of SSRIs to impair bone healing may adversely affect millions of patients’ ability to heal after sustaining trauma. Here, we investigate the effect of the SSRI sertraline on bone healing through pre-treatment with(10 mg·kg-1sertraline in drinking water, n = 26) or without(control, n = 30) SSRI followed by the creation of a 5-mm calvarial defect. Animals were randomized into three surgical groups:(a) empty/sham,(b) implanted with a DermaMatrix scaffold soak-loaded with sterile PBS or(c) DermaMatrix soak-loaded with542.5 ng BMP2. SSRI exposure continued until sacrifice in the exposed groups at 4 weeks after surgery. Sertraline exposure resulted in decreased bone healing with significant decreases in trabecular thickness, trabecular number and osteoclast dysfunction while significantly increasing mature collagen fiber formation. These findings indicate that sertraline exposure can impair bone wound healing through disruption of bone repair and regeneration while promoting or defaulting to scar formation within the defect site.
文摘In integrated circuits, the defects associated with photolithography are assumed to be in the shape of circular discs in order to perform the estimation of yield and fault analysis. However,real defects exhibit a great variety of shapes. In this paper,a novel yield model is presented and the critical area model of short circuit is correspondingly provided. In comparison with the circular model corrently available, the new model takes the similarity shape to an original defect, the two-dimensional distributional characteristic of defects, the feature of a layout routing and the character of yield estimation into account. As for the aspect of prediction of yield, the experimental results show that the new model may predict the yield caused by real defects more accurately than the circular model does. It is significant that the yield is accurately estimated and improved using the proposed model.
文摘Studies on ZnO ceramic varistors by deep heat treatment at 650–900 C are reported. The current creep time curve exhibits a peak during the continuous action of a dc biasing voltage; the forwardV-l characteristic is improved rather than degraded after the action of the biasing voltage. We assume that the zinc interstitial cations Zni are out diffused rapidly and the concentration of Zni in the depletion layer is decreased rapidly during deep heat treatment; the oxygen anions O’o could be accumulated at the grain interface if the out diffusion quantity of Zni is not enough to react with the O’o; the current creep phenomenon above results from the migration of the interface O’o by the biasing voltage. We suggest an improved grain boundary defect model for the ZnO varistors by deep heat treatment, and examine the model using the experimental data of lifetime positron-annihilation spectroscopy.
基金the National Natural Science Foundation of China (No. 81071235)the Medicine and Engineering Interdisciplinary Fund of Shanghai Jiaotong University (No. YG2010MS26)
文摘The biomechanical relationship between the articular cartilage defect and knee osteoarthritis (OA) has not been clearly defined. This study presents a 3D knee finite element model (FEM) to determine the effect of cartilage defects on the stress distribution around the defect rim. The complete knee FEM, which includes bones, articular cartilages, menisci and ligaments, is developed from computed tomography and magnetic resonance images. This FEM then is validated and used to simulate femoral cartilage defects. Based on the obtained results, it is confirmed that the 3D knee FEM is reconstructed with high-fidelity level and can faithfully predict the knee contact behavior. Cartilage defects drastically affect the stress distribution on articular cartilages. When the defect size was smaller than 1.00cm2, the stress elevation and redistribution were found undistinguishable. However, significant stress elevation and redistribution were detected due to the large defect sizes ( 1.00cm2). This alteration of stress distribution has important implications relating to the progression of cartilage defect to OA in the human knee joint.
基金The sustentation fund come fron China Academy of Engineering Physics 2003-421050504-12-02
文摘The importance of software residual defects and some prediction residual defects models are introduced. The problem that is not easy adapted to a general model is discussed. The model of prediction residual defects based on BBNs is proposed and the detailed processes of the approach are given.
文摘The pile, as an important foundation style, is being used in engineering practice. Defects of different types and damages of different degrees easily occur during the process of pile construction. So, dietecting defects of the pile is very important. As so far, there are some difficult problems in pile defect detection. Based on stress wave theory, some of these typical difficult problems were studied through model tests. The analyses of the test results are carried out and some significant results of the low-strain method are obtained, when a pile has a gradually-decreasing crosssection part, the amplitude of the reflective signal originating from the defect is dependent on the decreasing value of the rate of crosssection β. No apparent signal reflected from the necking appeares on the velocity response curve when the value of β is less than about 3. 5 %.
文摘Contaminated surfaces of the feedstock materials in aluminum alloy casting processes often produce various types of defects which can affect the tensile properties of the final products as well as their fatigue reliabilities.Semi-solid processing takes advantage of a much higher apparent viscosity of the die cast materials by limiting the risk of oxides formed at the free surfaces to become incorporated into the casting when the material is injected into the die.Most of existing semi-solid processes that use billets as feedstock material are however tied up with a different type of contaminated surface.During the injection phase,the external-skin on the periphery of the billet,which has been in contact with air and lubricant during the transfer in the shot sleeve,can be incorporated into the casting.When subjected to a heat treatment,the lubricant is decomposed and produces lens shape porosities.This might be a cause of reject for most structural parts.To avoid this kind of defects,the paths along which the billet skin evolves must be controlled during filling.In order to investigate the possibility of skin inclusion into cast parts during injection of the billet,a two-phase finite element mixture model is employed to model the metal flow.The formation of a skin on the periphery of the billet is modeled by setting an initial solid phase concentration profile in the radial direction.Microscopic observations of the real castings show that the approach is able to model the shear layers and to predict the paths along which the"lens porosity"defects could be formed.An Arbitrary Eulerian-Lagangian(ALE) method is also investigated and appears to be very promising to follow the skin movement in the casting.
文摘The shrinkage defect of a ductile iron casting is attributed to the volume variations occurring in solidification, which consist of liquid contraction, solidification shrinkage, graphitization expansion, and mold cavity enlargement. Based on this understanding, a mathematical model for predicting the shrinkage defect of the casting is developed, in which the volume variations of the casting in soli- dification are numerically simulated, especially, the mold cavity enlargement is quantitatively calculated. Moreover, the reliability of the model is verified in production and experiment.
文摘针对目前金属表面缺陷检测面临模型参数量大、精确度不足、工业现场部署困难等问题,提出了一种基于YOLOv8(you only look once version 8)的轻量化金属表面缺陷检测改进模型。该模型通过引入SCconv(spatial and channel reconst-ruction convolution)模块、C2f_Dual模块和倒残差多尺度注意力机制iEMA(inverted residual and efficient multi-scale attention),有效降低了模型参数量和计算量,同时提高了检测精度。实验使用SDI-YOLO在NEU-DET、Magnetic-Tile-Defect数据集上验证,mAP50分别比YOLOv8提高了2.5%、2.6%,参数量降低了15.6%,运算量减少了10.9%。与领域主流算法相比,SDI-YOLO在检测精度和参数量方面都有一定的优势,满足边缘设备部署中参数量较小、识别率高等需求。SDI-YOLO模型为金属表面缺陷检测提供了一种高效、轻量化的解决方案,具有重要的实际应用价值。
