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Vascularization in interconnected 3D printed Ti-6Al-4V foams with hydrogel matrix for biomedical bone replacement implants

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Science China materials 2018年第4期61卷 565-578页

作者： victor L.Correa Kristine m.Garza Lawrence E.murr Department of metallurgical Materials and Biomedical Engineering University of Texas at El Paso Department of Biological Sciences University of Texas at El Paso

Vascularization on newly implanted metal orthopedic implants has remained a challenge in the field of tissue engineering. To address this challenge, in this research,an interconnected foam structure of Ti-6 Al-4 V was microfabricated by electron beam melting(EBm) technique. The foam in question has a density of 1.77 g cm-3 with 60% porosity and a tensile strength of 18 GPa. An extracellular matrix based hydrogel was added as an aqueous matrix to the *** mimetic stress has been closely related to many wound healing biomedical applications as it increases survival and proliferation molecular signals. To that end, increased expression of hypoxia-inducible factor-1α(Hif-1α) and vascular endothelial growth factor(VEGF) in the aqueous hydrogel matrix was achieved by the addition of a hypoxia mimetic deferoxamine mesylate(DFm). In this study, the formation of an endothelial network was achieved in a hydrogel matrix in the presence of the before mentioned 3 D printed metal foam. Cellular viability, fluorescent microscopy and scanning electron microscopy imaging analysis demonstrate that pre-osteoblasts undergo proliferation and also attach efficiently to the foam when exposed to DFm. Human umbilical vascular endothelial cells(HUVECs) were grown in an extracellular matrix-like 3 D hydrogel and a hypoxia-like stress was achieved. This research demonstrates that pre-osteoblast cells undergo cell differentiation and increase the production of hydroxyapatite on exposure to the hypoxia mimetic molecule. This proposed approach encompasses an ideal prototype for a completely living implanted structure for future orthopedic implants.

关键词： Ti-6Al-4V electron beam melting angiogenesis deferoxamine mesylate hydrogel vascularization

Phasor-domain Dynamic model of Asymmetric Current Injection Controller for Converter-interfaced Generator

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Journal of modern Power Systems and Clean Energy 2021年第6期9卷 1269-1278页

作者： victor A.F.Almeida Glauco N.Taranto José m.T.marinho Electrical Engineering Department of the Federal University of Rio de Janeiro(COPPE/UFRJ) Petrobras S.A.

This paper presents a controller model of asymmetric current injection for converter-interfaced generators suitable for root-mean-square(RmS)phasor-domain,fundamentalfrequency,three-phase,and dynamic simulation *** effectiveness of the proposed controller is assessed with simulations in test systems with high percentage of converter-interfaced *** simulations focus on the operation of protection relays that use negative-sequence quantities in their directional *** paper also presents and compares two strategies to limit reactive negative-sequence currents,and active and reactive positive-sequence currents.A tutorial test system and a regional system part of the actual Brazilian Interconnected Power System are used to assess the correctness of the proposed controller in three-phase fundamental-frequency RmS dynamic simulations.

关键词： Converter-interfaced generator three-phase model power system protection negative-sequence current injection negative-sequence current protection unbalanced fault three-phase root-mean-square(RmS)dynamic simulation

Glacial reconstruction and periglacial dynamics at the end of Late Pleistocene on the surface of Cofre de Perote volcano,méxico:a climatological retrospective

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Journal of mountain Science 2023年第9期20卷 2453-2467页

作者： victor SOTO Hugo DELGADO-GRANADOS Carlos m.WELSH Kenji YOSHIKAWA Centro de Ciencias de la Tierra Universidad VeracruzanaXalapaVeracruz 91090México Instituto de Geofísica Universidad Nacional Autónoma de MéxicoCiudad de México 04150México Water and Environmental Research Center University of Alaska FairbanksFairbanksAlaska 99775USA

Despite being within the intertropical region of the planet,the mexican territory still has glacier-covered *** recent decades,important advances have been made in studies on glaciology and periglacial environment in mexico both for current and past ***,in spite of Cofre de Perote volcano(4200 m a.s.l.)being a strategically located mountain,it has not yet been studied in regards to the glacial and periglacial processes;in fact,those dynamics have modified the mountain massifs in the *** complement the series of studies on glacial history in the high mountain environment of méxico,this study reconstructs the glacial cover and the periglacial environment of the volcano surface during the final stage of the Late Pleistocene based on climatic retrospective and through the identification of geomorphological *** findings indicate the existence of a large glacier(ice cap)that covered the northern,western,and southern slopes of the mountain;while in the eastern sector there were two small glaciers,one being of cirque type,and the other of valley *** current temperature conditions prevent the occurrence of permanent ice bodies;at the same time,it was found that the periglacial blockfields of the slopes is a legacy of the climatic conditions that prevailed at the end of Late Pleistocene.

关键词： Cofre de Perote Glacial cover Periglacial environment Climatic retrospective Palaeoclimatic modelling

mathematics of microRNAs: stabilizing gene regulatory networks

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National Science Review 2019年第6期6卷 1189-1190页

作者： victor Ambros Program in molecular medicine University of Massachusetts Medical School

micro RNAs(miRNAs) are fascinating in their versatility. Animal cells express hundreds of distinct micro RNAs, and each micro RNA can regulate hundreds of distinct m RNA ***, in aggregate, the micro RNA compliment of a cell can exert pervasive effects on gene expression. Individual micro RNAs can also be potent determinants of phenotype: The

关键词： RNA stabilizing gene regulatory networks mathematics of microRNAs

Recent advances and future challenges for mobile network virtualization

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Science China(Information Sciences) 2017年第4期60卷 5-16页

作者： Xiaofeng TAO Yan HAN Xiaodong XU Ping ZHANG victor C.m.LEUNG National Engineering Lab for mobile Network Technologies Beijing University of Posts and Telecommunications State Key Lab of Networking & Switching Technology Beijing University of Posts and Telecommunications Department of Electrical and Computer Engineering The University of British Columbia

Recently, network function virtualization(NFV) was proposed as a paradigm shift in the telecommunication industry. Both industry and academia have drawn significant attention in mobile network *** decouples the software implementation of network functions from the underlying hardware, leading to considerable reductions in operating expenses(OPEX) and capital expenses(CAPEX), and facilitating the network deployment. However, as an emerging technology, NFV brings both challenges and opportunities in developing new architectures, applying and deployment. In this paper, we first survey the related work of NFV, and then propose promising research directions in this area.

关键词： network function virtualization mobile networks software defined networking network functions 5G network slicing

A multi-strain probiotic administered via drinking water enhances feed conversion efficiency and meat quality traits in indigenous chickens

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Animal Nutrition 2019年第2期5卷 179-184页

作者： Judith A.Atela victor mlambo Caven m.mnisi Animal Nutrition Group Department of Animal SciencesEgerton UniversityPO Box 536Egerton20115Kenya School of Agricultural Sciences Faculty of Agriculture and Natural SciencesUniversity of MpumalangaP Bagx2046Mmabatho2735South Arica Department of Animal Science Faculty of Natural and Agricultural ScienceNorth-West UniversityP Bag x20462735South Africa Food Security and Safety Niche Area Faculty of Natural and Agricultural ScienceNorth West UniversityMafikeng 2745South Africa

Whereas the use of probiotics is commonplace in commercial production of improved chicken strains,little is known about the impact of these live microbial feed additives in indigenous chickens in South Africa. This study investigated the effect of a multi-strain probiotic(containing Bacillus safensis, Bacillus subtilis, Bacillus megaterium and Cupriavidus metallidurans, total bacteria number was 1.4 × 10~8 cfu/mL),administered via drinking water, on growth performance, blood parameters, and carcass and meat quality characteristics of Potchefstroom koekoek cockerels for a period of 12 weeks. A total of 140 fiveweek-old cockerels were randomly allocated to 4 experimental diets formulated to have similar energy and protein levels as follows: 1) negative control diet(CON;commercial chicken grower diet without both antibiotics and probiotics), 2) positive control diet(ANTIB;commercial chicken grower diet with antibiotics [0.05% Coxistac and 0.04% olaquindox] but no probiotics), 3) negative control diet plus 2.5 mL of probiotics per litre of water(PROB25) and 4) negative control with 5.0 mL of probiotics per litre of water(PROB50). There was a significant(P ments had no significant(P > 0.05) effect on overall feed intake, overall weight gain and haemato-biochemical parameters of cockerels. Gizzard and spleen weights were similar(P > 0.05) in PROB50, CON and PROB25 groups. Cockerels in PROB50 group had shorter(P mall intestine than those in CON and PROB25 groups. Cockerels in PROB50 group had larger(P < 0.05) breast weight than those in PROB25 *** in ANTIB and PROB50 groups had greater(P < 0.05) wing and thigh weight

关键词： Antibiotics Blood parameters Indigenous chickens meat Probiotic

Larvicidal efficacy of plant extracts and isolated compounds from Annonaceae and Piperaceae against Aedes aegypti and Aedes albopictus

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Asian Pacific Journal of Tropical medicine 2020年第9期13卷 384-396页

作者： Alzeir m.Rodrigues victor Emanuel P.martins Selene m.morais Departamento de Ensino Instituto Federal de EducaçãoCiência e Tecnologia do Ceará(IFCE)Rodovia CE 060km 332Vila Martins63.560-000 AcopiaraCearáBrazil Programa de Pós-Graduação em Biotecnologia RENORBIOUniversidade Estadual do CearáAvenida Doutor Silas Munguba170060741-000 FortalezaCearáBrazil Instituto de Ciências Exatas e da Natureza Universidade da Integração Internacional da Lusofonia Afro-Brasileira(Unilab)Campus das AurorasRua JoséFranco de Oliveira s/n62790-970 RedençãoCearáBrasil Departamento de Química Universidade Estadual do CearáAvenida Doutor Silas Munguba170060741-000 FortalezaCearáBrazil

The Aedes(Ae.)aegypti and *** mosquitoes are vectors of epidemiologically relevant arboviruses in the public health context,such as the dengue,Zika and chikungunya *** the alternatives to synthetic insecticides for the control of these vectors,the use of natural plant products deserves *** review summarizes findings on the larvicidal potential of plant extracts on *** and ***,as well as the potential of isolated compounds from plants of the Annonaceae and Piperaceae families against these *** related to larvicidal activity of plant extracts and isolated compounds in Aedes *** the Web of Science database were used,for plant extracts considering publications between 2000 and 2019.A total of 859 articles were analyzed for plant extracts and estimates of lethal concentration values(LC50 and LC90).In the end,95 articles that presented the larvicidal potential of 150 plant species from 52 families were *** two families most studied for this activity were Fabaceae and Asterace *** plant families with the best LC50 values against mosquitoes were Piperaceae and *** activity of 50 acetogenins has already been identified on ***,and 29 of them presented LC50 below 10μg/mL,as well as the larvicidal activity of 8 compounds isolated from ***,plants of these two families are promising for the development of commercial botanical larvicides in the form of extracts and isolated substances,as well as the production via organic synthesis of the most active compounds.

关键词： Larvicidal activity Plant extracts Acetogenins Aedes

Arm PSA-Certified IoT Chip Security: A Case Study

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Tsinghua Science and Technology 2023年第2期28卷 244-257页

作者： Fei Chen Duming Luo Jianqiang Li victor C.m.Leung Shiqi Li Junfeng Fan College of Computer Science and Software Engineering Shenzhen UniversityShenzhen 518060China Department of Electrical and Computer Engineering the University of British ColumbiaVancouverBC V6T 1Z4Canada Open Security Research Inc.Shenzhen 518000China

With the large scale adoption of Internet of Things(IoT)applications in people’s lives and industrial manufacturing processes,IoT security has become an important problem *** security significantly relies on the security of the underlying hardware chip,which often contains critical information,such as encryption *** understand existing IoT chip security,this study analyzes the security of an IoT security chip that has obtained an Arm Platform Security Architecture(PSA)Level 2 *** analysis shows that the chip leaks part of the encryption key and presents a considerable security ***,we use commodity equipment to collect electromagnetic traces of the *** a statistical T-test,we find that the target chip has physical leakage during the AES encryption *** further use correlation analysis to locate the detailed encryption interval in the collected electromagnetic trace for the Advanced Encryption Standard(AES)encryption *** the basis of the intermediate value correlation analysis,we recover half of the 16-byte AES encryption *** repeat the process for three different tests;in all the tests,we obtain the same result,and we recover around 8 bytes of the 16-byte AES encryption ***,experimental results indicate that despite the Arm PSA Level 2 certification,the target security chip still suffers from physical *** layer application developers should impose strong security mechanisms in addition to those of the chip itself to ensure IoT application security.

关键词： Internet of Things(IoT)security chip Arm Platform Security Architecture(PSA)certification electromagnetic side-channel attack Advanced Encryption Standard(AES)encryption key leakage

A possible anorthositic continent of early mars and the role of planetary size for the inception of Earth-like life

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Geoscience Frontiers 2018年第4期9卷 1085-1098页

作者： James m.Dohm Shigenori maruyama motoyuki Kido victor R.Baker The University museum The University of Tokyo Earth-Life Science Institute Tokyo Institute of Technology International Research Institute of Disaster Science Tohoku University Lunar and Planetary Laboratory The University of Arizona

The moon has an anorthositic primordial continental crust. Recently anorthosite has also been discovered on the martian surface. Although the occurrence of anorthosite is observed to be very limited in Earth＇s extant geological record,both lunar and martian surface geology suggest that anorthosite may have comprised a primordial continent on the early Earth during the first 600 million years after its formation. We hypothesized that differences in the presence of an anorthositic continent on an Earthlike planet are due to planetary size. Earth likely lost its primordial anorthositic continent by tectonic erosion through subduction associated with a kind of proto-plate tectonics（PPT）. In contrast, mars and the moon, as much smaller planetary bodies, did not lose much of their anorthositic continental crust because mantle convection had weakened and/or largely stopped, and with time, they had appropriately cooled down. Applying this same reasoning to a super-Earth exoplanet suggests that, while a primordial anorthositic continent may briefly form on its surface, such a continent will be likely transported into the deep mantle due to intense mantle convection immediately following its formation. The presence of a primordial continent on an Earth-like planet seems to be essential to whether the planet will be habitable to Earth-like life. The key role of the primordial continent is to provide the necessary and sufficient nutrients for the emergence and evolution of life. With the appearance of a ＂trinity＂ consisting of（1） an atmosphere,（2） an ocean, and（3） the primordial continental landmass, material circulation can be maintained to enable a ＂Habitable Trinity＂ environment that will permit the emergence of Earth-like life. Thus, with little likelihood of a persistent primordial continent, a super-Earth affords very little chance for Earth-like life to emerge.

关键词： Anorthosite on mars moon Habitable trinity Super-Earth Plate tectonics Origin of life