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排序方式: 共有239条查询结果,搜索用时 31 毫秒
151.
Dr. Eijiro Miyako Dr. Julie Russier Dr. Matteo Mauro Dr. Cristina Cebrian Prof. Hiromu Yawo Dr. Cécilia Ménard‐Moyon Dr. James A. Hutchison Dr. Masako Yudasaka Prof. Sumio Iijima Prof. Luisa De Cola Dr. Alberto Bianco 《Angewandte Chemie (International ed. in English)》2014,53(48):13121-13125
A single organism comprises diverse types of cells. To acquire a detailed understanding of the biological functions of each cell, comprehensive control and analysis of homeostatic processes at the single‐cell level are required. In this study, we develop a new type of light‐driven nanomodulator comprising dye‐functionalized carbon nanohorns (CNHs) that generate heat and reactive oxygen species under biologically transparent near‐infrared (NIR) laser irradiation. By exploiting the physicochemical properties of the nanohorns, cellular calcium ion flux and membrane currents were successfully controlled at the single‐cell level. In addition, the nanomodulator allows a remote bioexcitation of tissues during NIR laser exposure making this system a powerful tool for single‐cell analyses and innovative cell therapies. 相似文献
152.
Charles B. Hutchison 《School science and mathematics》2006,106(2):74-83
U.S. schools have experienced a perennial shortage of teachers. Recently, many school districts have been inviting foreign veteran teachers to help mitigate such teacher shortages. This study describes the initial cross‐cultural issues four international science teachers encountered when they immigrated to teach in U.S. high schools. In‐depth, semistructured interviews of four science teachers (from Ghana, Britain, and Germany) produced the main source of data. The international teachers faced a variety of support system problems, which were not directly classroom related, but nevertheless had an impact on their instructional effectiveness. They also faced teaching‐related issues, including differences in school organization and structure, assessment and philosophical beliefs, communication, textbooks, teaching methods, and teacher‐student relations. They all expressed a need to become active learners in order to function effectively in their new teaching contexts. The implications are discussed based on the findings. 相似文献
153.
Chih-Hung Chang Brian K. Paul Vincent T. Remcho Sundar Atre James E. Hutchison 《Journal of nanoparticle research》2008,10(6):965-980
A critical barrier to the routine use of nanomaterials is the tedious, expensive means of their synthesis. Microreaction technology
takes advantage of the large surface area-to-volume ratios within microchannel structures to accelerate heat and mass transport.
This accelerated transport allows for rapid changes in reaction temperatures and concentrations leading to more uniform heating
and mixing which can have dramatic impacts on macromolecular yields and nanoparticle size distributions. Benefits of microreaction
technology include higher yield and reactant conversion, better energy efficiency and less by-product generation. Microreactors
can help minimize the environmental impact of nanoproduction by enabling solvent free mixing, integrated separation techniques
and reagent recycling. The possibility of synthesizing nanomaterials in the required volumes at the point-of-use eliminates
the need to store and transport potentially hazardous materials and provides the flexibility for tailoring complex functional
nanomaterials. Recognizing these benefits for nanosynthesis, continuous flow microreactors have been used by several research
groups to synthesize and characterize nanomaterials. An overview of these efforts and issues related to scale up and other
post synthesis processes such as separation and deposition are presented in this paper. 相似文献
154.
Three sharp absorption features in the energy range 2.36–2.55 eV have been detected in the transmission spectrum of Co-diffused ZnSe, and a number of luminescence transitions originating from the lowest of these states at 2.361 eV have been observed. Photoluminescence excitation spectra prove that these are high energy excited states of the Co2+Zn impurity, a conclusion confirmed by comparison of measured and predicted luminescence energies. This represents the first identification of luminescence branching from a higher excited state of a transition metal ion in any semiconductor. The sharp, weakly phonon-coupled transitions involve either intra-impurity excitation or transitions from the impurity to localised states split off from a minimum in the conduction band. The implications of these observations for the mechanism of host-impurity energy transfer and for the nature of the excited state wavefunctions are discussed. 相似文献
155.
W. D. Hutchison S. J. Harker D. H. Chaplin G. J. Bowden 《Hyperfine Interactions》2004,159(1-4):331-335
54Mn NMRON in the mixed halide antiferromagnet, Mn(Br
X
Cl1−X
)2 · 4H2O, for varying external field, is reported. Significant qualitative differences are found between these NMRON transitions
and those of the two terminal compounds, especially in respect to line widths. A tentative assignment is made to most of the
observed NMRON transitions out to 0.8 T. An unidentified lower frequency inhomogeneous signal, present only at the lowest
temperatures, with no counterpart in the terminal compounds, is also reported. 相似文献
156.
By measuring the phase angle of the photoacoustic signal it is possible to calculate the quantitative absorption spectrum of a condensed phase sample, if in addition only the sample thermal diffusivity is known. The technique also extends the upper limit of absorptivity which may be usefully studied photoacoustically by a factor of 10. 相似文献
157.
158.
159.
Flores-Torres S Hutchison GR Soltzberg LJ Abruña HD 《Journal of the American Chemical Society》2006,128(5):1513-1522
We have prepared and characterized a series of multimetallic oligomers of Ru using the pi-conjugated bridging ligand tetra-2-pyridyl-1,4-pyrazine (tppz), as well as mixed-ligand complexes with terpyridine end caps, and analyzed their electrochemical and spectroscopic properties, comparing them with modern computational electronic structure methods. The results suggest that the high degree of metal-metal interunit communication in these linear oligomers yields low HOMO-LUMO gaps, high delocalization, and the onset of "quasi-band" features, all indicative that these compounds should be excellent molecular wire materials. Recent spectroscopic and excited-state analyses of these and related compounds focus on optically accessible states, which ignore optically silent frontier electronic states more relevant to nanoelectronic applications. 相似文献
160.
Parks BW Gilbertson RD Hutchison JE Healey ER Weakley TJ Rapko BM Hay BP Sinkov SI Broker GA Rogers RD 《Inorganic chemistry》2006,45(4):1498-1507
This report describes an investigation into the coordination chemistry of trivalent lanthanides in solution and the solid state with acyclic and preorganized bicyclic malonamide ligands. Two experimental investigations were performed: solution binding affinities were determined through single-phase spectrophotometric titrations and the extent of conformational change upon binding was investigated with single-crystal X-ray crystallography. Both experimental methods compare the bicyclic malonamide (BMA), which is designed to be preorganized for binding trivalent lanthanides, to an analogous acyclic malonamide. Results from the spectrophotometric titrations indicate that BMA exhibits a 10-100x increase in binding affinity to Ln(III) over acyclic malonamide. In addition, BMA forms compounds with high ligand-metal ratios, even when competing with water and nitrate ligands for binding sites. The crystal structures exhibit no significant differences in the nature of the binding between Ln(III) and the BMA or acyclic malonamide. These results support the conclusion that rational ligand design can lead to compounds that enhance the binding affinities within a ligand class. 相似文献