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TUNED MECHANICAL PROPERTIES ACHIEVED BY VARYING POLYMER STRUCTURE-KNOWLEDGE THAT GENERATES NEW MATERIALS FOR TISSUE ENGINEERING

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Chinese Journal of Polymer Science 2007年第2期25卷 113-118页

作者： anna Finne Wistrand Ann-Christine Albertsson Department of Fiber and Polymer Technology Royal Institute of TechnologyStockholmSweden

By changing both the monomer composition and the polymer structure, we have varied the mechanical properties of resorbable polymers. The polymers were synthesized by ring-opening polymerization using L-lactide （LLA）, ε-caprolactone （εCL）, trimethylene carbonate （TMC） and 1,5-dioxepan-2-one （DXO） as monomers. Well-defined triblock copolymers, microblock copolymers and networks have been evaluated, and comparisons between them show that it is possible to tune the mechanical properties. Triblock copolymers with an amorphous middle block of poly（1,5-dioxepan-2- one）（PDXO） and semi-crystalline end-blocks of poly（ε-caprolactone）（PCL） were stronger and had a higher strain at break than triblock copolymers with poly（L-lactide）（PLLA） as end-blocks. Polymers with both DXO and TMC in the amorphous middle-block and PLLA as end-blocks showed a lower stress at break, but the material gained elasticity, a property which is very valuable in tissue engineering. Mechanical properties of networks, synthesized by a novel method, containing PDXO and PCL are also presented. Although it is difficult to compare them with the uncross-linked polymers, this is an additional way to modify and widen the properties.

关键词： Degradable polymer Tuneable mechanical properties Molecular architecture Block copolymers Networks.

Crystal structure and thermal expansion of perovskites containing uranium(VI) and rare-earth elements

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Journal of Rare Earths 2009年第1期27卷 4-11页

作者： Aleksandr Knyazev anna Ershova Nikolai Chernorukov Nizhny Novgorod State University

By the method of high-temperature reactions in solid phase, compounds with the general formula MⅡ（AⅢ2/3U1/3）O3（MⅡ=Sr, AⅢ=Sc, In;MⅡ=Ba, AⅢ=Sc, In, Y, Nd-Lu） were *** structures（space groups Fm 3 m and Pnma） were refined by the Rietveld method and morphotropic transition in Ba（Ln2/3U1/3）O3 on the border of Gd-Tb was *** means of high-temperature X-ray diffraction, phase transitions were studied and thermal expansion coefficients were determined.

关键词： perovskite uranium X-ray diffraction Rietveld structure thermal expansion rare earths

Global epigenetic changes during somatic cell reprogramming to iPS cells

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Journal of Molecular Cell Biology 2011年第6期3卷 341-350页

作者： anna Mattout Alva Biran Eran Meshorer Department of Genetics Institute of Life SciencesThe Hebrew University of JerusalemJerusalem 91904Israel

Embryonic stem cells(ESCs)exhibit unique chromatin features,including a permissive transcriptional program and an open,decondensed chromatin *** pluripotent stem cells(iPSCs),which are very similar to ESCs,hold great promise for therapy and basic ***,the mechanisms by which reprogramming occurs and the chromatin organization that underlies the reprogramming process are largely *** we characterize and compare the epigenetic landscapes of partially and fully reprogrammed iPSCs to mouse embryonic fibroblasts(MEFs)and ESCs,which serves as a standard for *** immuno-fluorescence and biochemical fractionations,we analyzed the levels and distribution of a battery of histone modifications(H3ac,H4ac,H4K5ac,H3K9ac,H3K27ac,H3K4me3,H3K36me2,H3K9me3,H3K27me3,and gH2AX),as well as HP1a and lamin *** find that fully reprogrammed iPSCs are epigenetically identical to ESCs,and that partially reprogrammed iPSCs are closer to ***,combining both time-course reprogramming experiments and data from the partially reprogrammed iPSCs,we find that heterochromatin reorganization precedes Nanog expression and active histone ***,these data delineate the global epigenetic state of iPSCs in conjunction with their pluripotent state,and demonstrate that heterochromatin precedes euchromatin in reorganization during reprogramming.

关键词： chromatin pluripotency reprogramming iPSCs ESCs histone modifications epigenetics

Evaluation of the plasmonic effect of Au and Ag on Ti-based photocatalysts in the reduction of CO2 to CH4

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Journal of Energy Chemistry 2017年第2期26卷 277-283页

作者： Martin Dilla anna Pougin Jennifer Strunk Max-Planck-Institute for Chemical Energy conversion Stiftstraße 34-3645470 Mülheim/RuhrGermany Laboratory of Industrial Chemistry Ruhr-University BochumUniversitätsstraße 15044780 BochumGermany Center for Nanointegration Duisburg-Essen University of Duisburg-EssenCarl-Benz-Straße 19947057 DuisburgGermany

Crystalline TiO（P25） and isolated titanate species in a ZSM-5 structure（TS-1） were modified with Au and Ag, respectively, and tested in the gas-phase photocatalytic COreduction under high purity conditions. The noble metal modification was performed by photodeposition. Light absorbance properties of the catalysts are examined with UV–Vis spectroscopy before and after the activity test. In the gas-phase photocatalytic COreduction, it was observed that the catalysts with Ag nanostructures are more active than those with Au nanostructures. It is thus found that the energetic difference between the band gap energy of the semiconductor and the position of the plasmon is influencing the photocatalytic ***, plasmon excitation due to visible light absorption results in plasmon resonance energy, which affects the excitation of the semiconductor positively. Therefore, an overlap between band gap energy of the semiconductor and metal plasmon is needed.

关键词： Photocatalytic CO2 reduction Plasmon resonance Methane formation TS-1 P25 Noble metal photodeposition High-purity gas-phase photoreactor

Experimental analysis of ballistic trauma in a human body protected with 30 layer packages made of biaxial and triaxial Kevlar^(■)29 fabrics

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Defence Technology（防务技术） 2023年第3期21卷 73-87页

作者： Justyna Pinkos Zbigniew Stempien anna Smędra Institute of Textile Architecture Lodz University of TechnologyLodzPoland Chair and Department of Forensic Medicine Medical University of LodzLodzPoland

Behind armour blunt trauma(BABT)is a body injury resulting from the deformation of the back surface of armour as a result of a bullet *** the case of textile body armour,the severity of the injury may depend on the material of the fibres,but also on the geometric structure of the *** article focuses on experimental research into injuries of the human body protected by ballistic packets made of biaxial and triaxial fabrics,during a non-penetrating impact from a Parabellum 9 mm×19 mm Full Metal Jacket(FMJ)bullet,at a speed of 406±5 m/*** experimental research,the fabrics had a comparable surface weight and were made of the same Kevlar^(■)29 *** ballistic packages were made of 30 *** part of the work,a physical model of the human body was *** human body model consisted of a model of the heart,lungs,and skeletal and muscular *** the bullet impact,the pressure forces were recorded using sensors located at selected points of the human *** bullets hit five selected places on the body that were considered critical,from the point of view of maintaining a human’s vital *** was found that,during firing,pressure increases both at the site of impact and in the internal organs,which can lead to multi-organ *** a result of the experimental analysis,it has been shown that the pressures exerted on specific organs are always lower in the case of body protection with a ballistic packet made of triaxial fabrics,compared to a packet made of biaxial fabrics.

关键词： protected impact organs

A critical review of national physical activity policies relating to children and young people in England

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Journal of Sport and Health Science 2021年第3期10卷 255-262,F0003页

作者： anna Chalkley Karen Milton School of Sport Exercise and Health SciencesLoughborough UniversityLoughborough LE113TUUK Norwich Medical School University of East AngliaNorwich NR47TJUK

Background:There has been an increasing focus on the importance of national policy to address population levels of physical *** has been suggested that the 4 cornerstones of policy comprise(1)national guidelines on physical activity(PA),(2)setting population goals and targets,(3)surveillance or health-monitoring systems,and(4)public *** current study aimed to review the policy actions that have addressed each of these elements for children and youth in England and to identify areas of progress and remaining ***:A literature search was undertaken to identify past and present documents relevant to PA policy for children and youth in *** document was analyzed to identify content relevant to the 4 cornerstones of ***:Physical activity guidelines(Cornerstone 1)for children and youth have been in place since 1998 and reviewed *** activity targets(Cornerstone 2)have focussed on the provision of opportunities for PA,mainly through physical education in schools rather than in relation to the proportion of children meeting recommended PA *** has been much surveillance(Cornerstone 3)of children’s PA,but this has been undertaken infrequently over time and with varying inclusions of differing domains of *** has been only 1 campaign(Cornerstone 4)that targeted children and their intermediaries,Change4Life,which was an obesity campaign focussing on dietary behavior in combination with *** recently,a government infographic supporting the PA guidelines for children and young people was developed,but details of its dissemination and usage are ***:There have been many developments in national PA policy in England targeted to children and young *** area of most significant progress is national PA *** prevalence targets,streamlining surveillance systems,and investing in public education with supportive policies,environments,and opportunities would st

关键词： Physical activity Policy Public education Recommendations Surveillance

Predetermination of potential plastic hinges on reinforced concrete frames using GFRP reinforcement

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Frontiers of Structural and Civil Engineering 2022年第5期16卷 624-637页

作者： Dominik KUERES Dritan TOPUZI Maria anna POLAK Department of Civil and Environmental Engineering University of WaterlooWaterlooON N2L 3G1Canada Schoeck Canada Inc. OttawaON K1P 5G3Canada

In the past,glass fiber-reinforced polymer(GFRP)-reinforcement has been successfully applied in reinforced concrete(RC)structures where corrosion resistance,electromagnetic neutrality,or cuttability were *** investigations suggest that the application of GFRP in RC structures could be advantageous in areas with seismic activity due to their high deformability and ***,especially the low modulus of elasticity of GFRP limited its wide application as GFRP-reinforced members usually exhibit considerably larger deformations under service loads than comparable steel-reinforced *** overcome the aforementioned issues,the combination of steel and GFRP reinforcement in hybrid RC sections has been investigated in the *** on this idea,this paper presents a novel concept for the predetermination of potential plastic hinges in RC frames using GFRP *** analyze the efficiency of the concept,nonlinear finite element simulations were *** results underscore the high efficiency of hybrid steel-GFRP RC sections for predetermining potential plastic hinges on RC *** results also indicate that the overall seismic behavior of RC structures could be improved by means of GFRP as both the column base shear force during the seismic activity as well as the plastic deformations after the earthquake were considerably less pronounced than in the steel-reinforced reference structure.

关键词： glass fiber-reinforced polymer GFRP hybrid section plastic hinge seismic design reinforced concrete

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The plant cell wall

Journal of Integrative Plant Biology 2015年第4期57卷 328-329页

作者： Kurt Fagerstedt anna Karkonen Department of Biosciences Division of Plant Biology University of Helsinki Department of Agricultural Sciences University of Helsinki

Research on the many aspects of the plant cell wall has experienced reiuvenation during the past few years. This is perhaps mainly due to the commercial interest in the chemical components of the cell wall that have potential for industrial use＂ Cellulose for fibers and together with hemicelluloses for bioethanol, lignin for plastics or biofuel, pectins as gel agents, let alone woody cell wall material for construction or pulp production and for intelligent materials for electronics - the new uses are mindboggling!

关键词： cell As The plant cell wall

Nonlinear interference in crystal superlattices

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Light(Science & Applications) 2020年第1期9卷 1239-1245页

作者： anna V.Paterova Leonid A.Krivitsky Institute of Materials Research and Engineering(IMRE) Agency for Science Technology and Research(A*STAR)138634 SingaporeSingapore

Nonlinear interferometers with correlated photons hold promise to advance optical characterization and metrology techniques by improving their performance and *** interferometers offer subshot noise phase sensitivity and enable measurements in detection-challenging regions using inexpensive and efficient *** sensitivity of nonlinear interferometers,defined by the ability to measure small shifts of interference fringes,can be significantly enhanced by using multiple nonlinear elements,or crystal ***,to date,experiments with more than two nonlinear elements have not been realized,thus hindering the potential of nonlinear ***,we build a nonlinear interferometer with up to five nonlinear elements,referred to as superlattices,in a highly stable and versatile *** study the modification of the interference pattern for different configurations of the superlattices and perform a proof-of-concept gas sensing experiment with enhanced *** approach offers a viable path towards broader adoption of nonlinear interferometers with correlated photons for imaging,interferometry,and spectroscopy.

关键词： spectroscopy nonlinear Nonlinear