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Mechanically induced Ca^(2+) oscillations in osteocytes release extracellular vesicles and enhance bone formation

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Bone Research 2018年第1期6卷 72-82页

作者： Andrea E.Morrell Genevieve N.Brown Samuel T.Robinson Rachel L.Sattler andrew D.baik Gehua Zhen Xu Cao Lynda F.Bonewald Weiyang Jin Lance C.Kam X.Edward Guo Bone Bioengineering Laboratory Department of Biomedical Engineering Columbia University Center for Musculoskeletal Research Department of Orthopaedic Surgery Johns Hopkins University Indiana Center for Musculoskeletal Health Indiana University School of Medicine Microscale Biocomplexity Laboratory Department of Biomedical Engineering Columbia University

The vast osteocytic network is believed to orchestrate bone metabolic activity in response to mechanical stimuli through production of sclerostin, RANKL, and osteoprotegerin(OPG). However, the mechanisms of osteocyte mechanotransduction remain poorly understood. We've previously shown that osteocyte mechanosensitivity is encoded through unique intracellular calcium (Ca^(2+) ) dynamics. Here, by simultaneously monitoring Ca^(2+) and actin dynamics in single cells exposed to fluid shear flow, we detected actin network contractions immediately upon onset of flow-induced Ca^(2+) transients, which were facilitated by smooth muscle myosin and further confirmed in native osteocytes ex vivo. Actomyosin contractions have been linked to the secretion of extracellular vesicles(EVs), and our studies demonstrate that mechanical stimulation upregulates EV production in osteocytes through immunostaining for the secretory vesicle marker Lysosomal-associated membrane protein 1(LAMP1) and quantifying EV release in conditioned medium, both of which are blunted when Ca^(2+) signaling was inhibited by neomycin. Axial tibia compression was used to induce anabolic bone formation responses in mice, revealing upregulated LAMP1 and expected downregulation of sclerostin in vivo. This load-related increase in LAMP1 expression was inhibited in neomycin-injected mice compared to ***-computed tomography revealed significant load-related increases in both trabecular bone volume fraction and cortical thickness after two weeks of loading, which were blunted by neomycin treatment. In summary, we found mechanical stimulation of osteocytes activates Ca^(2+) -dependent contractions and enhances the production and release of EVs containing bone regulatory proteins. Further, blocking Ca^(2+) signaling significantly attenuates adaptation to mechanical loading in vivo, suggesting a critical role for Ca^(2+) -mediated signaling in bone adaptation.

关键词： OPG conditioned medium Ca2+-dependent

Calcium signaling in osteocyte network

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医用生物力学 2010年第S1期25卷 22-24页

作者： X.Lucas Lu andrew D.baik Victor Chiang X.Edward Guo Bone Bioengineering Laboratory Department of Biomedical Engineering Columbia University

Introduction Osteocytes are interconnected through numerous intercellular processes,forming extensive cell networks throughout the bone tissue[1]. It has been shown that osteocyte density is an important physiological... 详细信息

关键词： AFM bone cell MEM MLO EMD

Intracellular calcium oscillations in live osteocytes in ex vivo intact mouse long bones under dynamic mechanical loading

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Intracellular calcium oscillations in live osteocytes in ex ...

A Hybrid Instance Selection Using Nearest-Neighbor for Cross-Project Defect Prediction

第十一届全国生物力学学术会议暨第十三届全国生物流变学学术会议

作者： Da Jing andrew D.baik X.Lucas Lu Bin Zhou X.Edward Guo Erping Luo Department of Biomedical Engineering Fourth Military Medical University Department of Biomedical Engineering Columbia University Department of Mechanical Engineering University of Delaware

Objective:Osteocyte networks have been hypothesized to be the central mechanosensory system in *** osteocyte networks in bone tissue sense and respond to mechanical stimuli has not been visualized and *** osteocyte mechanotransduction is critical to the etiology and treatments of osteoporosis and osteopetrosis as well as prevention of bone loss in future space *** recent in vitro results

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Journal of Computer Science & Technology 2015年第5期30卷 969-980页

作者： Duksan Ryu Jong-In Jang Jongmoon baik School of Computinq Korea Advanced Institute of Science and Technology Yuseong-gu Daejeon 305-701 Korea

Software defect prediction （SDP） is an active research field in software engineering to identify defect-prone modules. Thanks to SDP, limited testing resources can be effectively allocated to defect-prone modules. Although SDP requires sufficient local data within a company, there are cases where local data are not available, e.g., pilot projects. Companies without local data can employ cross-project defect prediction （CPDP） using external data to build classifiers. The major challenge of CPDP is different distributions between training and test data. To tackle this, instances of source data similar to target data are selected to build classifiers. Software datasets have a class imbalance problem meaning the ratio of defective class to clean class is far low. It usually lowers the performance of classifiers. We propose a Hybrid Instance Selection Using Nearest-Neighbor （HISNN） method that performs a hybrid classification selectively learning local knowledge （via k-nearest neighbor） and global knowledge （via na/ve Bayes）. Instances having strong local knowledge are identified via nearest-neighbors with the same class label. Previous studies showed low PD （probability of detection） or high PF （probability of false alarm） which is impractical to overall performance as well as high PD and low PF. use. The experimental results show that HISNN produces high overall performance as well as high PD and low PF.

关键词： software defect analysis instance-based learning nearest-neighbor algorithm data cleaning

Probabilistic seismic performance assessment of lap-spliced RC columns retrofitted by steel wrapping jackets

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Earthquake Engineering and Engineering Vibration 2016年第2期15卷 223-238页

作者： Eunsoo Choi Heejung Youn baik-Soon Cho Department of Civil Engineering Hongik University Department of Civil Engineering CTRCInje University

In this study, the seismic fragility curves of two reinforced concrete（RC） columns that were lap-spliced at the bottom and retrofitted with steel wrapping jackets were generated. Their seismic performance was probabilistically assessed in comparison to that of lap-spliced or continuous reinforcement RC columns. This study used two types of steel wrapping jackets, a full jacket and a split jacket. Analytical models of the four types of columns were developed based on the experimental results of the columns using Open SEES, which is effective in conducting nonlinear time history analyses. A suite of ten artificial ground motions, modified from recorded ground motions, was used to perform nonlinear time history analyses of the analytical models with scaling of the peak ground acceleration from 0.1 g to 1.0 g in increments of 0.1 g. The steel wrapping jackets did not increase the medians for yield（slight damage state） of the lap-spiced column and did not exceed the corresponding median of the continuous reinforcement column. However, the two steel jackets increased the medians for failure by 1.872 and 2.017 times, respectively, and exceeded the corresponding median of the continuous reinforcement column by 11.8% and 20.5%, respectively.

关键词： columns reinforcement reinforced exceed acceleration scaling median assessed split probabilistic

VQT:value cardinality and query pattern based R-schema to XML schema translation with implicit referential integrity

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第12期9卷 1694-1707页

作者： Jinhyung KIM Dongwon JEONG Doo-Kwon baik Department of Computer Science and Engineering Korea UniversitySeoul 136-713Korea Department of Informatics and Statistics Kunsan National UniversityKunsan 573-701Korea

In this paper,we propose a new relational schema (R-schema) to XML schema translation algorithm, VQT, which analyzes the value cardinality and user query patterns and extracts the implicit referential integrities by using the cardinality property of foreign key constraints between columns and the equi-join characteristic in user queries. The VQT algorithm can apply the extracted implied referential integrity relation information to the R-schema and create an XML schema as the final result. Therefore, the VQT algorithm prevents the R-schema from being incorrectly converted into the XML schema, and it richly and powerfully represents all the information in the R-schema by creating an XML schema as the translation result on behalf of the XML DTD.

关键词： Value cardinality Query pattern Relational schema XML schema Implicit referential integrity relations Explicit referential integrity

An XPath-based OWL storage model for effective ontology management in Semantic Web environment

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第6期10卷 843-857页

作者： Jinhyung KIM Dongwon JEONG Doo-kwon baik Department of Computer Science and Engineering Korea University Department of Informatics and Statistics Kunsan National University

With the rapid growth of the Web, the volume of information on the Web is increasing exponentially. However, information on the current Web is only understandable to humans, and this makes precise information retrieval difficult. To solve this problem, the Semantic Web was proposed. We must use ontology languages that can assign data the semantics for realizing the Semantic Web. One of the representative ontology languages is the Web ontology language OWL, adopted as a recommen-dation by the World-Wide Web Consortium (W3C). OWL includes hierarchical structural information between classes or prop-erties. Therefore, an efficient OWL storage model that considers a hierarchical structure for effective information retrieval on the Semantic Web is required. In this paper we suggest an XPath-based OWL storage (XPOS) model, which includes hierarchical information between classes or properties in XPath form, and enables intuitive and effective information retrieval. Also, we show the comparative evaluation results for the performance of the XPOS model, Sesame, and the XML file system-based storage (XFSS) model, in terms of query processing and ontology updating.

关键词： XPath Web ontology language Hierarchical structure Ontology storage Semantic Web

Physical Experiments to Investigate the Effects of Street Bottom Heating and Inflow Turbulence on Urban Street-Canyon Flow

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Advances in Atmospheric Sciences 2005年第2期22卷 230-237页

作者： Jae-Jin KIM Jong-Jin baik Climate Environment System Research Center Seoul National University Seoul 151-742 KoreaSchool of Earth and Environmental Sciences Seoul National University Seoul 151-742 Korea

The effects of street bottom heating and inflow turbulence on urbanstreet-canyon flow are experimentally investigated using a circulating water channel. Threeexperiments are carried out for a street canyon with a street aspect ratio of 1. Results from eachexperiment with bottom heating or inflow turbulence are compared with those without bottom heatingand appreciable inflow turbulence. It is demonstrated that street bottom heating or inflowturbulence increases the intensity of the canyon vortex. A possible explanation on how street bottomheating or inflow turbulence intensifies the canyon vortex is given from a fluid dynamicalviewpoint.

关键词： urban street-canyon flow street bottom heating inflow turbulence circulating water channel

Ballistic limit velocity of small caliber projectiles against SS400 steel plates:Live fire experiments and empirical models

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Defence Technology（防务技术） 2024年第11期41卷 22-34页

作者： Jong-Hwan Kim Seungwon baik Jirui Fu Joon-Hyuk Park Mechanical&Systems Engineering Korea Military Academy574 Hwarang-roNowon-guSeoul17977South Korea Mechanical and Aerospace Engineering University of Central Florida4000 Central Florida BlvdOrlandoFL 32816United States

This study presents the ballistic limit velocity of small caliber projectiles against SS400 steel plate derived from live-fire ballistic experiments. Four different small caliber projectiles were tested against SS400 steel plates of 9 mm, 10 mm, and 12 mm thicknesses. The ballistic limit velocity was calculated using two standard methods, MIL-STD-662F and NIJ-STD-0101.06, and additionally using a support vector machine algorithm. The results show a linear relationship between the plate thickness and ballistic limit velocity. Further, the relative penetration performance among five different small caliber projectiles was analyzed using the Penetration Performance Ratio(PPR) introduced in this study, which suggests the potential of PPR to predict the ballistic limit velocity of other untested materials and/or different projectiles.

关键词： Live fire ballistic experiment SS400 Ballistic limit velocity Small caliber projectile