24 research outputs found
Early bruising detection of ‘Korla’ pears by low-cost visible-LED structured-illumination reflectance imaging and feature-based classification models
IntroductionNondestructive detection of thin-skinned fruit bruising is one of the main challenges in the automated grading of post-harvest fruit. The structured-illumination reflectance imaging (SIRI) is an emerging optical technique with the potential for detection of bruises.MethodsThis study presented the pioneering application of low-cost visible-LED SIRI for detecting early subcutaneous bruises in ‘Korla’ pears. Three types of bruising degrees (mild, moderate and severe) and ten sets of spatial frequencies (50, 100, 150, 200, 250, 300, 350, 400, 450 and 500 cycles m-1) were analyzed. By evaluation of contrast index (CI) values, 150 cycles m-1 was determined as the optimal spatial frequency. The sinusoidal pattern images were demodulated to get the DC, AC, and RT images without any stripe information. Based on AC and RT images, texture features were extracted and the LS-SVM, PLS-DA and KNN classification models combined the optimized features were developed for the detection of ‘Korla’ pears with varying degrees of bruising.Results and discussionIt was found that RT images consistently outperformed AC images regardless of type of model, and LS-SVM model exhibited the highest detection accuracy and stability. Across mild, moderate, severe and mixed bruises, the LS-SVM model with RT images achieved classification accuracies of 98.6%, 98.9%, 98.5%, and 98.8%, respectively. This study showed that visible-LED SIRI technique could effectively detect early bruising of ‘Korla’ pears, providing a valuable reference for using low-cost visible LED SIRI to detect fruit damage
Hippo Signaling Suppresses Cell Ploidy and Tumorigenesis through Skp2
大多数真核生物的体细胞是二倍体,即仅含有两组染色体,分别遗传自父本和母本。而一些特定组织如心脏、肝脏等就含有多倍体细胞,特别是肝脏组织含有较高比例的四、八倍体等多倍体细胞。肝脏是人体的重要解毒器官,同时酒精、肝炎病毒等毒性物质或毒性代谢物容易诱发肝细胞的基因突变,多倍体被认为有利于提供代偿性的正常基因来维持肝脏稳态。然而肝脏受损后,多倍体细胞将会受胁迫进行增殖,再生修复受损的肝组织。因此研究机体调控多倍体细胞产生及多倍体细胞进行细胞分裂的调控机理对于理解肝癌的发病机理和肝癌的治疗至关重要。Hippo信号通路在调节组织成体干细胞的分化和增殖,调控器官再生与尺寸大小中具有重要作用。深入研究发现, Hippo信号通路下游效应分子YAP通过AKT-SKP2信号促进二倍体细胞向多倍体转化及多倍体细胞的生长增殖。本项研究阐明了Hippo缺失及YAP激活促进多倍体细胞产生及增殖作为肝癌发生发展中的一个重要机制,为肝癌诊疗提供了新的策略。
周大旺,博士,厦门大学生命科学学院教授、副院长、国家杰出青年基金获得者。【Abstract】Polyploidy can lead to aneuploidy and tumorigenesis. Here, we report that the Hippo pathway effector Yap promotes the diploid-polyploid conversion and polyploid cell growth through the Akt-Skp2 axis. Yap strongly induces the acetyltransferase p300-mediated acetylation of the E3 ligase Skp2 via Akt signaling. Acetylated Skp2 is exclusively localized to the cytosol, which causes hyper-accumulation of the cyclin-dependent kinase inhibitor p27, leading to mitotic arrest and subsequently cell polyploidy. In addition, the pro-apoptotic factors FoxO1/3 are overly degraded by acetylated Skp2, resulting in polyploid cell division, genomic instability, and oncogenesis. importantly, the depletion or inactivation of Akt or Skp2 abrogated Hippo signal deficiency-induced liver tumorigenesis, indicating their epistatic interaction. Thus, we conclude that Hippo-Yap signaling suppresses cell polyploidy and oncogenesis through Skp2.该研究工作获得了国家自然科学基金委、国家重点基础研究发展计划(973)项目、青年千人计划和中央高校基本科研基金的资助。
The Yap (S127A) transgenic mice were kindly provided by Dr. Fernando Camargo from Harvard Medical School, Boston, MA. D.Z. and L.C. were supported by the National Natural Science Foundation of China (31625010,U1505224, and J1310027 to D.Z.; 81422018, U1405225, and 81372617 to L.C.; 81472229 to L.H.), the National Basic Research Program (973) of China (2015CB910502 to L.C.), the Fundamental Research Funds for the Central Universities of China-Xiamen University (20720140551 to L.C. and 2013121034 and 20720140537 to D.Z.)
Hippo信号通路通过调控Skp2活性从而抑制细胞多倍体产生及肝癌发生
文章简介在这项研究中,课题组揭示了Hippo信号通路在限制肝脏细胞的染色体由两倍体向多倍/非整倍体转变过程中起关键作用,该机制异常将导致基因组不稳定继而诱发肝癌的发生发展。课题组通过对Hippo信号通路重要成员(WW45,Mst1/2,Lats1/2)肝脏特异性敲除和过表达国家自然科学基金委;;国家重点基础研究发展计划(973)项目;;青年千人计划;;中央高校基本科研基金的资
RESEARCH ON LOAD FLUCTUATION CHARACTERISTICS OF SUPPORT BEARING RACEWAY FOR SPECIAL VEHICLE LIFT MECHANISM
The load fluctuation of the transmission system are important factors that cause equipment fatigue,and the fatigue failure has been the most common failure mode of the transmission system. Therefore,a special vehicle lift mechanism transmission system has been regarded as the research object,the three-dimensional model of the main components of the transmission system has been established,and the influences of the bolt design on the load fluctuation characteristics of support bearing raceway of transmission system have been analyzed by the finite element and vibration frequency detection methods. The research results show that the bolt pre-tightening force in the transmission system change the contact deformation of the raceway of the supporting bearing and then affect the contact load of the supporting bearing. Under the combination influence of the bolt pretightening force and the external load,the supporting bearing contact load fluctuate greatly,which reduce the fatigue life of the supports bearing of transmission system obviously. The optimization of the wall thickness of the supports bearing,reducing the pre-tightening force of the bolt,and increasing the distance between the bolt hole and the supports bearing can effectively reduce the cyclic fluctuation load for the supports bearing of transmission system,thereby improving the fatigue life of the transmission system; the vibration of the transmission system was reduced after optimization. The research provides a theoretical basis for the comprehensive transmission improvement of the performance of transmission system,and the improvement of the fatigue life of the support bearing
Part Design of Giant Magnetostrictive Actuator
AbstractThe key parts of giant magnetostrictive actuator, flexure hinge and pre-stress disc spring, were designed and analyzed. Rotation stiffness and strength characteristics of flexure hinge were analyzed, calculation equations for rotation stiffness and strength were established as well. Fatigue characteristic was also analyzed as flexure hinge usually worked under high frequency situation. In order to improve output efficiency of the giant magnetostrictive actuator and reduce energy loss, an ideal spring force-deformation curve, whose shape was bilinear broken line, of the pre- stress disc spring was put forward, and a disc spring was designed by configuring its geometric parameters to make its spring force-deformation curve was approximate to the ideal spring force-deformation curve
The Pattern and Local Push Factors of Rural Depopulation in Less-Developed Areas: A Case Study in the Mountains of North Hebei Province, China
Rural depopulation is the most significant geographical phenomenon in rural areas during the process of urbanization. Although many studies have investigated the driving force of rural depopulation based on rural-urban migration at the macro level, the local factors, and their impact on rural depopulation from the rural areas have been not fully revealed. This paper selected the northern mountains of China’s Hebei province as a study area to explore the pattern and local push factors of rural depopulation at the rural-township levels based on GeoDetector. The main findings are summarized as follows. (1) Rural depopulation varies substantially, demonstrates spatial correlation, and is distributed in clusters. From a dynamic perspective, compare that in years 2000–2010, the population growth areas during 2010–2017 have been significantly expanded, while the sharp depopulation areas and severe depopulation areas experienced shrinkage in our study area. (2) The pattern of rural depopulation is in accordance with terrain. Rural depopulation tends to be stronger in plateaus and mountains, while relatively milder in intermontane basins, hills, and piedmont plains. (3) The agricultural suitability of natural environmental and rural economic opportunities together with climate changes were the most important driving forces of rural depopulation at local levels. Location, sparse population, and inadequate public services also contributed to rural depopulation. However, the dominant driving factors are different in the different periods. Rural depopulation was mainly driven by arable land per capita and natural environmental variables in the years 2000–2010, while the population density, location, and off-farm economic opportunities played a decisive role in the years 2010–2017. (4) Rural depopulation is a complex, multi-dimensional process driven by a combination of multiple factors including different environmental factors, economic opportunities, and location. This paper reveals the push factors of rural depopulation in underdeveloped mountainous areas by a quantitative empirical approach, inspiring increased attention to the impacts of local factors and spatial correlations on rural depopulation, and has many implications for the policy design of China’s rural revitalization
The research on improving the salt resistance of bentonite used in Geosynthetic Clay Liner
Geosynthetic Clay Liner, a water-proofing material which takes polymer as its carrier and bentonite as its basis, has been widely applied in the seepage-proofing projects including irrigation works, gardening and roadbed. In order to improve salt-resistance of bentonite used in Geosynthetic Clay Liner in saline environment, this paper innovatively uses chemical methods to modify the bentonite material. The experimental result shows that the optimum conditions are 100% of acrylic neutralization degree, 0.04%MBA, 1.2%KPS and holding at 70 degrees C for 1 h. According to results of soil moisture supply capacity (MSC), swelling capacity of modified samples raises 30% similar to 170%
Unraveling the mechanism of action of cepharanthine for the treatment of novel coronavirus pneumonia (COVID-19) from the perspectives of systematic pharmacology
Natural products play an irreplaceable role in the treatment of SARS-CoV-2 infection. Nevertheless, the underlying molecular mechanisms involved remain elusive. To better understand their potential therapeutic effects, more validation studies are needed to explore underlying mechanisms systematically. This study aims to explore the potential targets of action and signaling pathways of cepharanthine for the treatment of COVID-19. This study revealed that a total of 173 potential targets of action for Cepharanthine and 86 intersectional targets for Cepharanthine against COVID-19 were screened and collected. Gene Ontology enrichment analysis suggested that inflammatory, immune cell and enzyme activities were the critical terms for cepharanthine against COVID-19. Pathway enrichment analysis showed that five pathways associated with COVID-19 were the main signaling pathways for the treatment of COVID-19 via cepharanthine. Molecular docking and molecular dynamics simulations suggested that 6 core targets were regarded as potential targets for cepharanthine against COVID-19. In brief, the study demonstrates that cepharanthine may play an important role in the treatment of SARS-CoV-2 infection through its harmonious activity against SARS-CoV-2 pathways and multiple related targets. This article provides valuable insights required to respond effectively to concerns of western medical community
Tribological behavior of extruded spray-forming 2195-T6 Al-Li alloy at different loads using pin-on-disk tribotester
The tribological properties of Al-Li alloys impact the reliability of components used in different industrial sectors. In this research, the effect of normal load on friction and wear properties of the extruded spray-formed 2195-T6 Al-Li alloy is investigated by using a pin-on-disk tester. Through the microstructure of the friction subsurface, it is evaluated that the friction coefficient of 2195 alloy decreases from 0.408 to 0.306 by increasing load (25 N to 150 N), while the wear rate increases exponentially. It is also analyzed that a mild-severe wear transition occurs between 100 N and 125 N and the main wear mechanism gradually shifts from abrasive wear and oxidative wear to delamination wear (25 N ∼ 100 N), and finally attains the state of severe plastic deformation (125 N ∼ 150 N). Under the action of normal load and friction shearing force, the deformation layer in the subsurface increases from 3 μ m to 43 μ m with increasing load, and the accumulation of strain leads to cracks and holes