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Genetic evidence in planar cell polarity signaling pathway in human neural tube defects

null

《医学前沿（英文）》 2014年 第8卷 第1期   页码 68-78 doi: 10.1007/s11684-014-0308-4

摘要：

Neural tube defects (NTDs) are a group of birth anomalies having a profound physical, emotional, and financial effects on families and communities. Their etiology is complex, involving environmental and genetic factors that interact to modulate the incidence and severity of the developing phenotype. The planar cell polarity (PCP) pathway controls the process of convergent extension (CE) during gastrulation and neural tube closure and has been implicated in the pathogenesis of NTDs in animal models and human cohorts. This review summarizes the cumulative results of recent studies on PCP signaling pathway and human NTDs. These results demonstrate that PCP gene alterations contribute to the etiology of human NTDs.

关键词： planar cell polarity     neural tube defects     rare mutations    

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Automated classification of civil structure defects based on convolutional neural network

Pierclaudio SAVINO, Francesco TONDOLO

《结构与土木工程前沿（英文）》 2021年 第15卷 第2期   页码 305-317 doi: 10.1007/s11709-021-0725-9

摘要： Today, the most commonly used civil infrastructure inspection method is based on a visual assessment conducted by certified inspectors following prescribed protocols. However, the increase in aggressive environmental and load conditions, coupled with the achievement of many structures of the life-cycle end, has highlighted the need to automate damage identification and satisfy the number of structures that need to be inspected. To overcome this challenge, this paper presents a method for automating concrete damage classification using a deep convolutional neural network. The convolutional neural network was designed after an experimental investigation of a wide number of pretrained networks, applying the transfer-learning technique. Training and validation were conducted using a database built with 1352 images balanced between “undamaged”, “cracked”, and “delaminated” concrete surfaces. To increase the network robustness compared to images in real-world situations, different image configurations have been collected from the Internet and on-field bridge inspections. The GoogLeNet model, with the highest validation accuracy of approximately 94%, was selected as the most suitable network for concrete damage classification. The results confirm that the proposed model can correctly classify images from real concrete surfaces of bridges, tunnels, and pavement, resulting in an effective alternative to the current visual inspection techniques.

关键词： concrete structure     infrastructures     visual inspection     convolutional neural network     artificial intelligence    

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Tomographic diagnosis of defects in hydraulic concrete structure

ZHAO Mingjie, XU Xibin

《结构与土木工程前沿（英文）》 2008年 第2卷 第3期   页码 226-232 doi: 10.1007/s11709-008-0027-5

摘要： The ultrasonic tomographic technology is applied to diagnose the defects in hydraulic concrete structure. In order to improve the precision of diagnoses, the wavelet transformation is used in the processing of ultrasonic signals. The influences of water, scale and orientation of defect, processing methods and theoretical model on image resolution are investigated. The experimental results indicate that the result of the tomographic diagnosis of a single defect is sensitive and the boundary can be clearly determined. However, the image resolution of multiple defects is not satisfactory. The water content and scale of a defect may significantly affect the imaging resolution. Defects with the orientation perpendicular to the direction of the diagnosis may have higher precision in diagnosing. The wavelet transformation technology can elevate the imaging resolution. The applied calculation model plays a very important role in improving the accuracy of detection.

关键词： satisfactory     processing     orientation     tomographic diagnosis     orientation perpendicular    

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“Charging” the cigarette butt: heteroatomic porous carbon nanosheets with edge-induced topological defects

《化学科学与工程前沿（英文）》 2023年 第17卷 第11期   页码 1755-1764 doi: 10.1007/s11705-023-2318-8

摘要： Owing to the complexity of electron transfer pathways, the sluggish oxygen evolution reaction process is defined as the bottleneck for the practical application of Zn–air batteries. In this effort, metal nanoparticles (Co, Ni, Fe, etc.) encapsulated within nitrogen-doped carbon materials with abundant edge sites were synthesized by one-step pyrolysis treatment using cigarette butts as raw materials, which can drastically accelerate the overall rate of oxygen evolution reaction by facilitating the adsorption of oxygenated intermediates by the edge-induced topological defects. The prepared catalyst of nitrogen-doped carbon porous nanosheets loaded with Co nanoparticles (Co@NC-500) exhibits enhanced catalytic activity toward oxygen evolution reaction, with a low overpotential of 350 mV at the current density of 10 mA·cm–2. Furthermore, the Zn–air battery assembled with Co@NC-500 catalyst demonstrates a desirable performance affording an open-circuit potential of 1.336 V and power density of 33.6 mW·cm–2, indicating considerable practical application potential.

关键词： oxygen evolution reaction     porous carbon nanosheets     Co nanoparticles     edge-induced topological defects     Zn–air batteries    

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Thermal reffusivity: uncovering phonon behavior, structural defects, and domain size

Yangsu XIE, Bowen ZHU, Jing LIU, Zaoli XU, Xinwei WANG

《能源前沿（英文）》 2018年 第12卷 第1期   页码 143-157 doi: 10.1007/s11708-018-0520-z

摘要： To understand the relation between different nanostructures and thermal properties, a simple yet effective model is in demand for characterizing the underlying phonons and electrons scattering mechanisms. Herein, we make a systematic review on the newly developed thermal reffusivity theory. Like electrical resistivity which has been historically used as a theory for analyzing structural domain size and defect levels of metals, the thermal reffusivity can also uncover phonon behavior, structure defects and domain size of materials. We highlight that this new theory can be used for not only metals, but also nonmetals, even for amorphous materials. From the thermal reffusivity against temperature curves, the Debye temperature of the material and the ideal thermal diffusivity of single perfect crystal can be evaluated. From the residual thermal reffusivity at the 0 K limit, the structural thermal domain (STD) size of crystalline and amorphous materials can be obtained. The difference of white hair and normal black hair from heat conduction perspective is reported for the first time. Loss of melanin results in a worse thermal protection and a larger STD size in the white hair. By reviewing the different variation of thermal reffusivity against decreasing temperature profiles, we conclude that they reflected the structural connection in the materials. Ultimately, the future application of thermal reffusivity theory in studying 2D materials and amorphous materials is discussed.

关键词： thermal reffusivity theory     phonon behavior     structure defects     structural thermal domain (STD) size     2D material     amorphous material    

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Determining casting defects in near-net shape casting aluminum parts by computed tomography

Jiehua LI, Bernd OBERDORFER, Daniel HABE, Peter SCHUMACHER

《机械工程前沿（英文）》 2018年 第13卷 第1期   页码 48-52 doi: 10.1007/s11465-018-0493-y

摘要：

Three types of near-net shape casting aluminum parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting (Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy), die casting (A356, Al-7Si-0.3Mg), and semi-solid casting (A356, Al-7Si-0.3Mg), respectively. Unlike die casting (second part), low-pressure die casting (first part) significantly reduced the formation of casting defects (i.e., porosity) due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi-solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.

关键词： near-net shape casting     aluminum parts     casting defects     low pressure die casting     die casting     semi-solid casting     computed tomography    

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Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 606-624 doi: 10.1007/s11709-023-0925-6

摘要： A novel cambered surface steel tube damper (CSTD) with a cambered surface steel tube and two concave connecting plates is proposed herein. The steel tube is the main energy dissipation component and comprises a weakened segment in the middle, a transition segment, and an embedded segment. It is believed that during an earthquake, the middle weakened segment of the CSTD will be damaged, whereas the reliability of the end connection is ensured. Theoretical and experimental studies are conducted to verify the effectiveness of the proposed CSTD. Formulas for the initial stiffness and yield force of the CSTD are proposed. Subsequently, two CSTD specimens with different steel tube thicknesses are fabricated and tested under cyclic quasi-static loads. The result shows that the CSTD yields a stable hysteretic response and affords excellent energy dissipation. A parametric study is conducted to investigate the effects of the steel tube height, diameter, and thickness on the seismic performance of the CSTD. Compared with equal-stiffness design steel tube dampers, the CSTD exhibits better energy dissipation performance, more stable hysteretic response, and better uniformity in plastic deformation distributions.

关键词： cambered surface steel tube damper     energy dissipation capacity     finite element model     hysteretic performance     parametric study    

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Detection of solder bump defects on a flip chip using vibration analysis

Junchao LIU, Tielin SHI, Qi XIA, Guanglan LIAO

《机械工程前沿（英文）》 2012年 第7卷 第1期   页码 29-37 doi: 10.1007/s11465-012-0314-7

摘要：

Flip chips are widely used in microelectronics packaging owing to the high demand of integration in IC fabrication. Solder bump defects on flip chips are difficult to detect, because the solder bumps are obscured by the chip and substrate. In this paper a nondestructive detection method combining ultrasonic excitation with vibration analysis is presented for detecting missing solder bumps, which is a typical defect in flip chip packaging. The flip chip analytical model is revised by considering the influence of spring mass on mechanical energy of the system. This revised model is then applied to estimate the flip chip resonance frequencies. We use an integrated signal generator and power amplifier together with an air-coupled ultrasonic transducer to excite the flip chips. The vibrations are measured by a laser scanning vibrometer to detect the resonance frequencies. A sensitivity coefficient is proposed to select the sensitive resonance frequency order for defect detection. Finite element simulation is also implemented for further investigation. The results of analytical computation, experiment, and simulation prove the efficacy of the revised flip chip analytical model and verify the effectiveness of this detection method. Therefore, it may provide a guide for the improvement and innovation of the flip chip on-line inspection systems.

关键词： flip chip     defect detection     ultrasonic excitation     vibration analysis    

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Diagnosis of sewer pipe defects on image recognition of multi-features and support vector machine in

Xiangyang Ye, Jian’e Zuo, Ruohan Li, Yajiao Wang, Lili Gan, Zhonghan Yu, Xiaoqing Hu

《环境科学与工程前沿（英文）》 2019年 第13卷 第2期 doi: 10.1007/s11783-019-1102-y

摘要：

An image-recognition-based diagnosis system of pipe defect types was established.

1043 practical pipe images were gathered by CCTV robot in a southern Chinese city.

The overall accuracy of the system is 84% and the highest accuracy is 99.3%.

The accuracy shows positive correlation to the number of training samples.

关键词： Sewer pipe defects     Defect diagnosing     Image recognition     Multi-features extraction     Support vector machine    

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Transversal tube pitch effects on local heat transfer characteristics of the flat tube bank fin mounted

Liangbi WANG, Zhimin LIN, Kangjie SUN, Yuanxin DONG, Song LIU, Yongheng ZHANG,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 333-345 doi: 10.1007/s11708-009-0061-6

摘要： The tube bank fin is commonly used to increase the area of the heat transfer surface with a small heat transfer coefficient of a heat exchanger. If vortex generators (VGs) are punched on the fin surface, the heat transfer performance of the fin can be improved. This paper focused on the effect of transversal tube pitch on the local heat transfer performance of the three-row flat tube bank fin mounted with VGs. On the fin surface, constructing the flow channel but without mounted VGs, the transversal tube pitch was greater, and the span averaged Nusselt number downstream was larger because fewer interactions of vortices would be generated from different VGs located upstream. When the area goodness factor was used as the criteria on the condition of one tube unit of heat exchanger for commonly used fin materials and fin thickness, the transversal tube pitch has considerable effect on the heat transfer enhancement of VGs. Large transversal tube pitch is more sensitive to fin material than to fin thickness.

关键词： heat transfer enhancement     vortex generator     finned flat tube bank     heat exchanger    

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Energy distribution between liquid hydrogen and liquid oxygen temperatures in a Stirling/pulse tube refrigerator

《能源前沿（英文）》 2023年 第17卷 第4期   页码 516-526 doi: 10.1007/s11708-022-0844-6

摘要： A two-stage gas-coupled Stirling/pulse tube refrigerator (SPR), whose first and second stages respectively involve Stirling and pulse tube refrigeration cycles, is a very promising spaceborne refrigerator. The SPR has many advantages, such as a compact structure, high reliability, and high performance, and is expected to become an essential refrigerator for space applications. In research regarding gas-coupled regenerative refrigerator, the energy flow distribution between the two stages, and optimal phase difference between the pressure wave and volume flow, are two critical parameters that could widely influence refrigerator performance. The effects of displacer displacement on the pressure wave, phase difference, acoustic power distribution, and inter-stage cooling capacity shift of the SPR have been investigated experimentally. Notably, to obtain the maximum first-stage cooling capacity, an inflection point in displacement exists. When the displacer displacement is larger than the inflection point, the cooling capacity could be distributed between the first and second stages. In the present study, an SPR was designed and manufactured to work between the liquid hydrogen and liquid oxygen temperatures, which can be used to cool small-scale zero boil-off systems and space detectors. Under appropriate displacer displacement, the SPR can reach a no-load cooling temperature of 15.4 K and obtain 2.6 W cooling capacity at 70 K plus 0.1 W cooling capacity at 20 K with 160 W compressor input electric power.

关键词： Stirling/pulse tube refrigerator     displacer displacement     space application     phase shift     energy distribution    

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Experimental and statistical investigation of a new concrete-composite beam with encased polymer tube

Abdelmadjid SI SALEM,Souad AIT TALEB,Kamal AIT TAHAR

《结构与土木工程前沿（英文）》 2015年 第9卷 第2期   页码 154-162 doi: 10.1007/s11709-015-0296-8

摘要： A new concrete-composite beam with high mechanical performances to weight ratio is developed in this study. The proposed design technique consists to embed a cylindrical polymer tube wrapped by a GFRP Jacket in the mechanically ineffective concrete tensile zone. An experimental investigation is carried out on composite beams under bending loads until failure to evaluate the flexural capacity and the corresponding failure mechanisms. Based on the experimental results, statistical and preliminary reliability analyses using the FORM method are performed to assess the safety margin of the new beam. The confrontation between test and simulation results shows a satisfactory agreement, and represents a promising revelation regarding the improvement in terms of strength and ductility of such design compared to conventional reinforced concrete beams with traditional one.

关键词： design     GFRP-Jacket     polymer tube     test     reliability analysis    

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Tuning nitrogen defects and doping sulfur in carbon nitride for enhanced visible light photocatalytic

《化学科学与工程前沿（英文）》 2023年 第17卷 第1期   页码 93-101 doi: 10.1007/s11705-022-2175-x

摘要： Defect construction and heteroatom doping are effective strategies for improving photocatalytic activity of carbon nitride (g-C3N4). In this work, N defects were successfully prepared via cold plasma. High-energy electrons generated by plasma can produce N defects and embed sulfur atoms into g-C3N4. The N defects obviously promoted photocatalytic degradation performance that was 7.5 times higher than that of pure g-C3N4. The concentration of N defects can be tuned by different power and time of plasma. With the increase in N defects, the photocatalytic activity showed a volcanic trend. The g-C3N4 with moderate concentration of N defects exhibited the highest photocatalytic activity. S-doped g-C3N4 exhibited 11.25 times higher photocatalytic activity than pure g-C3N4. It provided extra active sites for photocatalytic reaction and improved stability of N defects. The N vacancy-enriched and S-doped g-C3N4 are beneficial for widening absorption edge and improving the separation efficiency of electron and holes.

关键词： g-C3N4     nitrogen defect     sulfur doping     photodegradation     plasma    

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Loss of liver kinase B1 causes planar polarity defects in cochlear hair cells in mice

null

《医学前沿（英文）》 2016年 第10卷 第4期   页码 481-489 doi: 10.1007/s11684-016-0494-3

摘要：

The tumor suppressor gene liver kinase B1 (LKB1), also called STK11, encodes a serine/threonine kinase. LKB1 plays crucial roles in cell differentiation, proliferation, and polarity. In this study, LKB1 conditional knockout mice (LKB1Pax2 CKO mice) were generated using Pax2-Cre mice to investigate the function of LKB1 in inner ear hair cells during early embryonic period. LKB1Pax2 CKO mice died perinatally. Immunofluorescence and scanning electron microscopy revealed that stereociliary bundles in LKB1Pax2 CKO mice were clustered and misoriented, respectively. Moreover, ectopic distribution of kinocilium bundles resulting from abnormal migration of kinocilium was observed in the mutant mice. The orientation of stereociliary bundles and the migration of kinocilia are critical indicators of planar cell polarity (PCP) of hair cells. LKB1 deficiency in LKB1Pax2 CKO mice thus disrupted hair cell planar polarity during embryonic development. Our results suggest that LKB1 is required in PCP formation in cochlear hair cells in mice.

关键词： LKB1     stereociliary bundles     kinocilium     planar cell polarity     hearing     mice    

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Thermal-hydraulic performance of novel louvered fin using flat tube cross-flow heat exchanger

DONG Junqi, CHEN Jiangping, CHEN Zhijiu

《能源前沿（英文）》 2008年 第2卷 第1期   页码 99-106 doi: 10.1007/s11708-008-0010-9

摘要： Experimental studies were conducted to investigate the air-side heat transfer and pressure drop characteristics of a novel louvered fins and flat tube heat exchangers. A series of tests were conducted for 9 heat exchangers with different fin space and fin length, at a constant tube-side water flow rate of 2.8 m/h. The air side thermal performance data were analyzed using the effectiveness-NTU method. Results were presented as plot of Colburn factor and friction factor against the Reynolds number in the range of 500–6500. The characteristics of the heat transfer and pressure drop of different fin space and fin length were analyzed and compared. In addition, the curves of the heat transfer coefficients vs. pumping power per unit heat transfer area were plotted. Finally, the area optimization factor was used to evaluate the thermal hydraulic performance of the louvered fins with differential geometries. The results showed that the and factors increase with the decrease of the fin space and fin length, and the fin space has more obvious effect on the thermal hydraulic characteristics of the novel louvered fins.

关键词： obvious effect     different     thermal hydraulic     constant tube-side     Colburn    

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标题 作者 时间 类型 操作

Genetic evidence in planar cell polarity signaling pathway in human neural tube defects

null

期刊论文

Automated classification of civil structure defects based on convolutional neural network

Pierclaudio SAVINO, Francesco TONDOLO

期刊论文

Tomographic diagnosis of defects in hydraulic concrete structure

ZHAO Mingjie, XU Xibin

期刊论文

“Charging” the cigarette butt: heteroatomic porous carbon nanosheets with edge-induced topological defects

期刊论文

Thermal reffusivity: uncovering phonon behavior, structural defects, and domain size

Yangsu XIE, Bowen ZHU, Jing LIU, Zaoli XU, Xinwei WANG

期刊论文

Determining casting defects in near-net shape casting aluminum parts by computed tomography

Jiehua LI, Bernd OBERDORFER, Daniel HABE, Peter SCHUMACHER

期刊论文

Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

期刊论文

Detection of solder bump defects on a flip chip using vibration analysis

Junchao LIU, Tielin SHI, Qi XIA, Guanglan LIAO

期刊论文

Diagnosis of sewer pipe defects on image recognition of multi-features and support vector machine in

Xiangyang Ye, Jian’e Zuo, Ruohan Li, Yajiao Wang, Lili Gan, Zhonghan Yu, Xiaoqing Hu

期刊论文

Transversal tube pitch effects on local heat transfer characteristics of the flat tube bank fin mounted

Liangbi WANG, Zhimin LIN, Kangjie SUN, Yuanxin DONG, Song LIU, Yongheng ZHANG,

期刊论文

Energy distribution between liquid hydrogen and liquid oxygen temperatures in a Stirling/pulse tube refrigerator

期刊论文

Experimental and statistical investigation of a new concrete-composite beam with encased polymer tube

Abdelmadjid SI SALEM,Souad AIT TALEB,Kamal AIT TAHAR

期刊论文

Tuning nitrogen defects and doping sulfur in carbon nitride for enhanced visible light photocatalytic

期刊论文

Loss of liver kinase B1 causes planar polarity defects in cochlear hair cells in mice

null

期刊论文

Thermal-hydraulic performance of novel louvered fin using flat tube cross-flow heat exchanger

DONG Junqi, CHEN Jiangping, CHEN Zhijiu

期刊论文