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931.
Novel bifunctional terbium complex-based nanoparticles were developed using a modified Stber method and a layer-by-layer assembly process. A magnetic core of Fe3O4 nanoparticles was coated with a silica shell to form the first layer. Then a ternary Tb3+ complex (TESPPA-Tb), which acted as a luminescent marker, was covalently bound to the silica surface by stable Si-O-Si bonds. The TESPPA monomer was synthesized by binding pyridine 2,6-dicarboxylic acid to 3-aminopropyltriethoxysilane, which was used as a ligand for coordination with the Tb3+ ions. An outer shell of silica was applied to the nanoparticles to allow for versatility with surface functionalization. The nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, ultravioletvisible spectroscopy, vibration sample magnetometer, and photoluminescence spectroscopy. The bifunctional nanoparticles exhibited favorable superparamagnetic behavior and photoluminescence properties of Tb3+. These nanoparticles have potential applications in biolabeling, bioseparation, immunoassays, and pathogenic diagnosis. 相似文献
932.
In occupational therapy education in South Africa, community service (CS) focuses learning opportunities during fieldwork
placements. CS therefore enabled the researcher to utilise successive small scale research projects to guide learning of students
during fieldwork while simultaneously developing the occupational therapy service at a residential care facility. This community
setting provided a powerful environment through which research, in combination with opportunities for reflection, contributed
to nurturing skills needed by these future health professionals. A technical action research (AR) approach incorporated AR
cycles and opportunities for structured reflection. Therefore situations were created for the students to embrace experiential
learning. Experiential learning in the form of anticipatory reflection, reflection-in-action, reflection on reflection and
retrospective reflection impacted on the quality of the students’ work. Besides encouraging unique leaning opportunities for
students when engaging in research during their fieldwork placement, engagement in AR cycles simultaneously improved service
delivery to residents in the facility. Key benefits of this investigation were that fieldwork education utilising AR cycles
within a CS situation promoted students to identify voids in their theoretical background as well as practice skills; to apply
reflective practice that could contribute to their personal and professional development; and to utilize learning opportunities
optimally. Despite positive gains showed by this study, the role of power relations between the researcher as fieldwork educator
and the students prohibited the AR cycles from being more emancipatory in nature and should be addressed in follow-up studies. 相似文献
933.
Sandrine Turcotte Thérèse Laferrière Christine Hamel Alain Breuleux 《Systemic Practice and Action Research》2010,23(4):285-299
Small remote rural schools in Quebec face an ongoing challenge to provide similar quality educational services than bigger
schools. Since 2002, the Remote Network Schools (RNS) initiative afforded schools the opportunity to reinvent their practice
by using online tools to experience collaborative learning activities with other remote schools. Teachers and students experienced
quality learning and demonstrated agency by implementing the RNS in their context. Measures include: diversity of learning
activities, quality of online classroom interactions, changes in teacher beliefs, and shifts in teacher and student roles.
Our results show that it is a viable operating method for such schools and that other schools could contemplate implementing
such innovative practices. 相似文献
934.
Maria C. Shina Annette Müller-Taubenberger Can Ünal Michael Schleicher Michael Steinert Ludwig Eichinger Rolf Müller Rosemarie Blau-Wasser Gernot Glöckner Angelika A. Noegel 《Cellular and molecular life sciences : CMLS》2011,68(2):303-313
Dictyostelium discoideum harbors a short (CRN12) and a long coronin (CRN7) composed of one and two beta-propellers, respectively. They are primarily
present in the cell cortex and cells lacking CRN12 (corA
−) or CRN7 (corB
−) have defects in actin driven processes. We compared the characteristics of a mutant cell line (corA
−
/corB
−) lacking CRN12 and CRN7 with the single mutants focusing on cytokinesis, phagocytosis, chemotaxis and development. Cytokinesis,
uptake of small particles, and developmental defects were not enhanced in the corA
−
/corB
− strain as compared to the single mutants, whereas motility and phagocytosis of yeast particles were more severely impaired.
It appears that although both proteins affect the same processes they do not act in a redundant manner. Rather, they often
act antagonistically, which is in accordance with their proposed roles in the actin cytoskeleton where CRN12 acts in actin
disassembly whereas CRN7 stabilizes actin filaments and protects them from disassembly. 相似文献
935.
校外实习基地是培养学生实践能力和创新精神的重要场所,是学生顺利进行实习的重要保障.当前本校光伏专业校外实习基地建设存在一些问题,需要通过双师型教师的培养、实习岗位多样化、校企产学研合作等方式,提高光伏专业校外实习基地的建设水平. 相似文献
936.
In this paper,we propose a new image denoising method that combines total variation(TV) method and wavelet shrinkage. In our method,a noisy image is decomposed into subbands of LL,LH,HL,and HH in wavelet domain. LL subband contains the low frequency coefficients along with less noise,which can be easily eliminated using TV-based method. More edges and other detailed information like textures are contained in the other three subbands,and we propose a shrinkage method based on the local variance to extract th... 相似文献
937.
The security issues of mobile agent system have embarrassed its widespread implementation. The paper analyses communication security threats and countermeasures of mobile agent system and proposes a communication security protocol of mobile agent system. It provides multifactor authentication, encryption transmission, and integrity protection of mobile agent. 相似文献
938.
<正> In this paper,an equivalency condition of nonsingularity in nonlinear semidefinite programming,which can be viewed as a generalization of the equivalency condition of nonsingularity for linearsemidefinite programming,is established under certain conditions of convexity. 相似文献
939.
<正> A family of integral-type goodness-of-fit tests is investigated.This family includes someexisting tests,such as the Cramér-von Mises test and Anderson-Darling test,etc.The asymptoticdistributions of the tests in the family under the null and local alternative hypotheses are established.The almost sure convergence under a fixed underlying distribution is obtained.Furthermore,simulationsare conducted to compare the powers of the tests in the family.Simulation results show that fordifferent alternatives,the more powerful tests are different,and the parameter λ has great influence onthe tests in small sample cases. 相似文献
940.
Titanium produces different compounds in gray iron. In order to determine their characteristics, a scanning electron microscope, an energy dispersive X-ray spectroscopy, and an optical microscopy were used to analyze the morphology, distribution, and composition of titanium-containing compounds in metal- Iographic specimens and machined surfaces in four gray irons. The results show that the titanium-containing compounds in the gray irons are complex compounds containing V, Nb, Mn, S, and other metals, depending on the concentration of these elements in the iron. The number of titanium-containing compounds increases with increasing Ti content in the gray iron. Most of the titanium-containing compounds are located in the pearlite matrix, with some in the steadite and carbides. The results suggest that titanium-containing compounds reduce tool lifetime. 相似文献