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991.
To control the activity of photosensitized singlet oxygen ((1)O(2)) generation, the electron donor-connecting porphyrin, 5-(9'-anthryl)-10,15,20-tris(p-pyridyl)porphyrin (AnTPyP), was designed and synthesized. AnTPyP became water-soluble by the protonation of the pyridyl moieties in the presence of 5 mM trifluoroacetic acid (pH 2.3). The photoexcited state of the porphyrin ring in an AnTPyP molecule was effectively deactivated by intramolecular electron transfer from the anthracene moiety within 0.04 ns in an aqueous solution. The deactivation was suppressed by the interaction with a DNA strand, resulting in the elongation of the lifetime of the porphyrin excited state and the enhancement of the fluorescence intensity. Furthermore, it was confirmed that the interaction enabled the photoexcited AnTPyP to generate (1)O(2). Selective (1)O(2) generation by forming a complex with DNA should be the initial step to realize the target selective photodynamic therapy. 相似文献
992.
We have synthesized two novel push-pull-type fluorescent 7-deazapurine nucleosides, CNZA and CNZG, and investigated their photophysical properties. In particular, CNZA was found to exhibit a remarkable solvatofluorochromicity (Δλfl.max = 60 nm). We incorporated CNZA into oligonucleotides and found that CNZA can form a stable base pair with both thymine and cytosine. Such environmentally sensitive fluorescent nucleosides have a potential as a fluorescence sensor for structural studies of nucleic acids. 相似文献
993.
Contactless dielectrophoretic spectroscopy: examination of the dielectric properties of cells found in blood 总被引:1,自引:0,他引:1
The use of non-invasive methods to detect and enrich circulating tumor cells (CTCs) independent of their genotype is critical for early diagnostic and treatment purposes. The key to using CTCs as predictive clinical biomarkers is their separation and enrichment. This work presents the use of a contactless dielectrophoresis (cDEP) device to investigate the frequency response of cells and calculate their area-specific membrane capacitance. This is the first demonstration of a cDEP device which is capable of operating between 10 and 100 kHz. Positive and negative dielectrophoretic responses were observed in red blood cells, macrophages, breast cancer, and leukemia cells. The area-specific membrane capacitances of MDA-MB231, THP-1 and PC1 cells were determined to be 0.01518 ± 0.0013, 0.01719 ± 0.0020, 0.01275 ± 0.0018 (F/m(2)), respectively. By first establishing the dielectrophoretic responses of cancerous cells within this cDEP device, conditions to detect and enrich tumor cells from mixtures with non-transformed cells can be determined providing further information to develop methods to isolate these rare cells. 相似文献
994.
995.
This paper reports the synthesis and characterization of a novel series of chain-like compounds where oxo-centered triruthenium cluster moieties are bridged by 4,4'-bipyridine (4,4'-bpy) spacers. A reaction of solvent-coordinated triruthenium "monomer" precursor [Ru(3)O(CH(3)CO(2))(6)(CO)(CH(3)OH)(2)] with a 0.1 equimolar amount of 4,4'-bpy in CH(3)OH gave mixture of chain-like compounds containing "dimers" to "tetramers" which were cleanly separated by column chromatography and characterized by spectroscopic and electrochemical methods. Cyclic voltammetry revealed that all chain-like compounds exhibit reversible and stepwise redox processes in solution with very weak intramolecular coupling between the triruthenium components across the 4,4'-bpy bridge. Photo-induced dissociation of CO from the compounds and electrode surface binding were also investigated. 相似文献
996.
Tsujimoto Y Li JJ Yamaura K Matsushita Y Katsuya Y Tanaka M Shirako Y Akaogi M Takayama-Muromachi E 《Chemical communications (Cambridge, England)》2011,47(11):3263-3265
The first Ruddlesden-Popper type layered cobalt oxyfluoride, Sr(2)CoO(3)F, has been synthesized under a pressure of 6 GPa at 1700 °C and shown to adopt a K(2)NiF(4)-type structure with distorted square pyramidal coordination around Co and with O/F disorder at the apical sites. 相似文献
997.
Guan H Wang X Chen S Bando Y Golberg D 《Chemical communications (Cambridge, England)》2011,47(44):12098-12100
A new concept for fabricating novel triple-layered nanorod array electrodes made of coaxial Cu-Si@C arrays has been developed. They exhibit excellent electrochemical performance resulting from peculiar new sandwiched architectures: robust Cu nanopillar cores/amorphous Si layers/elastic carbon shells. 相似文献
998.
Nanda Gunawardhana Nikolay Dimov Manickam Sasidharan Gum-Jae Park Hiroyoshi Nakamura Masaki Yoshio 《Electrochemistry communications》2011,13(10):1116-1118
Lithium deposition on graphite anodes is considered as a main reason for failures and safety for lithium ion batteries (LIB). Different amounts of carbon coating on the surface of natural graphite are used in this work to suppress the amount of lithium deposited at − 10 °C. Pulse polarization experiments reveal relative polarization of graphite anodes at various temperatures and show that lithium deposition is accelerated at lowered temperatures. Electrochemical experiments, along with photographs, scanning electron microscopy (SEM) images and ex-situ X-ray diffraction (XRD) data suggest that carbon coating not only suppresses the lithium deposition but also enhances the formation of LiC6 at − 10 °C. The homogeneous potential profile on the graphite surface attained by the carbon coating explains such an improved low temperature performance, as it allows efficient Solid Electrolyte Interface (SEI) film formation, which is a prerequisite for safety LIB. 相似文献
999.
Hikaru Morimoto Marie Minato Tomohiko Nakagawa Masahide Sato Yoshio Kobayashi Kohsuke Gonda Motohiro Takeda Noriaki Ohuchi Noboru Suzuki 《Journal of Sol-Gel Science and Technology》2011,59(3):650-657
A preparation method for gadolinium compound (Gd) nanoparticles coated with silica (Gd/SiO2) is proposed. Gd nanoparticles were prepared with a homogeneous precipitation method at 80 °C using 1.0 × 10−3 M Gd(NO3)3 and 0.5 M urea in the presence of 1.0 g/L stabilizer. Among stabilizers examined. Sodium n-dodecyl sulfate (SDS) was suitable
as the stabilizer for preparing small Gd nanoparticles, and consequently Gd nanoparticles with a size of 46.2 ± 12.4 nm were
prepared using the SDS. Silica-coating of the Gd nanoparticles was performed by a St?ber method at room temperature using
0.013 M TEOS and 2.0 × 10−3 M NaOH in water/1-propanol solution in the presence of 1.0 × 10−3 M Gd nanoparticles, which resulted in production of Gd/SiO2 particles with an average size of 64.2 ± 14.4 nm. The Gd/SiO2 particles were surface-modified with 3-aminopropyltrimethoxysilane and succinic anhydride. It was confirmed by measurement
of electrophretic light scattering that amino group or carboxyl group was introduced onto the Gd/SiO2 particles. The gadolinium concentration of 1.0 × 10−3 M in the as-prepared colloid solution was increased up to a gadolinium concentration of 0.4 M by centrifugation. The core–shell
structure of Gd/SiO2 particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The
concentrated Gd/SiO2 colloid solution showed an X-ray image with contrast as high as a commercial Gd complex contrast agent. Internal organs in
a mouse could be imaged injecting the concentrated colloid solution into it. 相似文献
1000.