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161.
Nakano M Minami T Fukui H Kishi R Shigeta Y Champagne B 《The Journal of chemical physics》2012,136(2):024315
The second hyperpolarizability (γ) of the one-dimensional H(4) model compound has been calculated at the full configuration interaction level to describe its relationships with the diradical characters y(i) [the occupation numbers of the lowest unoccupied natural orbital (LUNO) + i] and the geometry. It is found that the system with intermediate y(0) ( = 0.527) and small y(1) ( = 0.178) exhibits the largest γ value [enhanced by a factor of 9 compared to that of a nearly closed-shell H(4) analog (y(0) = 0.099, y(1) = 0.029)], where both the outer H-H distances are slightly larger than the inner one. These results provide a molecular design guideline for enhancing and controlling the third-order nonlinear optical properties of singlet multiradical linear molecular systems such as multiradical organic aggregates, supermolecular systems, and extended metal atom chains. 相似文献
162.
Kihoon Jang Yan Xu Kae Sato Yo Tanaka Kazuma Mawatari Takehiko Kitamori 《Mikrochimica acta》2012,176(1-2):49-55
Platinum nanoparticles were electrodeposited onto a film of dihexadecyl hydrogen phosphate deposited on a glassy carbon electrode (GCE) and modified with dispersed acetylene black. Scanning electron microscopy and electrochemical impedance spectroscopy revealed that this nanocomposite has a uniform nanostructure and a large surface area that enables fast electron-transfer kinetics. The modified GCE showed high electrocatalytic activity for the oxidation of nitric oxide (NO). Under optimal conditions, the oxidation peak current of nitric oxide is linearly related to the concentration of NO in the concentration range between 0.18 and 120?μM, and the detection limit is as low as 50?nM (at an S/N of 3). The modified electrode was successfully applied to sensing of NO as released from rat liver. Figure
Acetylene black (AB) was dispersed with dihexadecyl hydrogen phosphate (DHP) and modified on the surface of glassy carbon electrode (GCE) to fabricate AB/GCE, after activating in NaOH solution, the AB film became more porous and loosened, then through electrodepositing Pt nanoparticles (PtNPs) on the activated AB film, PtNP/AB/GCE was obtained, which was denoted as NO electrochemical sensor. 相似文献
163.
Highly sensitive near-infrared fluorescent probes for nitric oxide and their application to isolated organs 总被引:5,自引:0,他引:5
Sasaki E Kojima H Nishimatsu H Urano Y Kikuchi K Hirata Y Nagano T 《Journal of the American Chemical Society》2005,127(11):3684-3685
Novel near-infrared (NIR) fluorescent probes for nitric oxide (NO) have been designed, synthesized, and evaluated. Their NIR fluorescence was increased in an NO concentration-dependent manner under physiological conditions, and their reaction efficiency with NO was at least 53 times higher than that of a widely used NO probe, DAF-2. They were confirmed to function in isolated intact rat kidneys. Because NIR light can penetrate deeply into tissues, these probes may have potential for in vivo NO imaging. 相似文献
164.
Ryu Kojima Kazuma Mawatari Björn Renberg Takehiko Tsukahara Takehiko Kitamori 《Mikrochimica acta》2009,164(3-4):307-310
We report on the first successful miniaturization of sandwich immunoassay into an extended nanospace channel for the detection of alpha-fetoprotein. A fused silica microchip with a nanochannel flanked by two microchannels, to facilitate liquid handling, was constructed using photo- and electron beam lithography, ICP and thermal bonding. Reagents could be selectively introduced into the nanochannel and the flow be stopped by using a pressure controller that alternatively opened and closed inlet and outlet ports. The construction and handling of the nano-in-microchip device for immunoassay is described. 相似文献
165.
Naoyuki Toriumi Norihito Asano Takayuki Ikeno Atsuya Muranaka Kenjiro Hanaoka Yasuteru Urano Masanobu Uchiyama 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(23):7870-7873
Near‐infrared (NIR) imaging techniques have attracted significant attention for biological and medicinal applications due to the ability of NIR to penetrate deeply into tissues. However, there are very few stable, activatable molecular probes that can utilize NIR light in the wavelength range beyond 800 nm. Herein, we report a new activatable NIR system for photoacoustic imaging based on tautomeric benziphthalocyanines (BPcs). We found that the existence of a free hydroxyl group is crucial for NIR absorption of BPcs. Synthesized water‐soluble hydroxy BPcs exhibited high photostability and no fluorescence, which are desirable features for photoacoustic imaging. We synthesized BPcs in which the free hydroxyl group was masked by an esterase‐labile or an H2O2‐labile group. The photoacoustic signals of these hydroxy‐masked BPcs were increased upon NIR excitation at 880 nm in the presence of esterase or H2O2, respectively. These are rare examples of activatable probes utilizing NIR light at around 900 nm. 相似文献
166.
Atsushi Miyasaka Minoru Nakamura Yasuteru Mawatari Kazuhiko Orito Masayoshi Tabata 《Macromolecular Symposia》2006,239(1):13-20
Novel soluble polyacetylenes having a triphenylamine moiety were synthesized by a [Rh(norbornadiene)Cl]2 catalyst under quite mild conditions in fairly high yields. The obtained polymer showed to have trans-transoid sequence as the major main-chain structure which was generated through the so-called cis-to-trans isomerization was already induced even during the polymerization. The HCl doping of the polymer was resulted in the formation of the oxidized polymer where the so-called polaron or bipolaron was produced. In addition, we found that in the case of the pristine polymer unpaired electrons mainly localized on the triphenylamine moiety as the side chain. On the other hand, after the doping the unpaired electron delocalized on the main chain of the polymer. 相似文献
167.
Imai M Mawatari R Nakaya K Komura S 《The European physical journal. E, Soft matter》2004,13(4):391-400
We have investigated the effects of a guest component (polymer or spherical colloidal particle) confined between flexible lamellar slits on the inter-lamellar interaction by means of a small-angle X-ray scattering technique and a neutron spin echo technique. The dominant interaction between flexible lamellar membranes without guest components is the Helfrich mechanism. The addition of a neutral polymer into the lamellar phase induces an attractive inter-lamellar interaction and finally destabilizes the lamellar phase. On the other hand, spherical colloidal particles confined between flexible lamellar membranes reduce the undulational fluctuations of lamellae and bring a repulsive inter-lamellar interaction. The behavior of the layer compression modulus of the lamellar membrane containing colloidal particles is well described by the entropical repulsive inter-lamellar interaction driven by steric hindrance.Received: 26 March 2004, Published online: 4 May 2004PACS:
82.70.Uv Surfactants, micellar solutions, vesicles, lamellae, amphiphilic systems, (hydrophilic and hydrophobic interactions) - 61.25.Hq Macromolecular and polymer solutions; polymer melts; swelling - 83.80.Hj Suspensions, dispersions, pastes, slurries, colloids - 89.75.Fb Structures and organization in complex systems 相似文献
168.
Bioaccumulation and biomethylation of inorganic arsenic were investigated in a three-step fresh-water food chain consisting of an autotroph (blue- green alga: Nostoc sp.), a herbivore (shrimp: Neocaridina denticulata) and a carnivore (carp: Cyprinus carpio). The autotroph, herbivore and carnivore survived in arsenic-containing water below 1000, 2 and 60 mg As(V) dm?3, respectively. Bioaccumulation of arsenate by Nostoc sp. was decreased with an increase in the nitrogen concentration of the medium. Arsenic(V) was accumulated from the water phase and part-methylated by the carp, as well as by the algae and shrimp. Arsenic was mostly accumulated in the gut of the carp. The predominant arsenical in the guts was the monomethylarsenic species. Arsenic accumulation via food in the above three-step food chain decreased by one order of magnitude and the relative concentration of methylated arsenic to the total arsenic accumulated increased successively with an elevation in the trophic level. When arsenicals were transferred via the food chain, no monomethylarsenic, or only a trace amount, was detected in the three organisms. Dimethylarsenic in the alga, both dimethyl- and trimethyl-arsenic in shrimp, and trimethyl-arsenic in carp, were the predominant methylated arsenic species, respectively. 相似文献
169.
170.
Kamiya M Kobayashi H Hama Y Koyama Y Bernardo M Nagano T Choyke PL Urano Y 《Journal of the American Chemical Society》2007,129(13):3918-3929
Beta-galactosidase is a widely used reporter enzyme, but although several substrates are available for in vitro detection, its application for in vivo optical imaging remains a challenge. To obtain a probe suitable for in vivo use, we modified our previously developed activatable fluorescence probe, TG-betaGal (J. Am. Chem. Soc. 2005, 127, 4888-4894), on the basis of photochemical and photophysical experiments. The new probe, AM-TG-betaGal, provides a dramatic fluorescence enhancement upon reaction with beta-galactosidase, and further hydrolysis of the ester moiety by ubiquitous intracellular esterases affords a hydrophilic product that is well retained within the cells without loss of fluorescence. We used a mouse tumor model to assess the practical utility of AM-TG-betaGal, after confirming that tumors in the model could be labeled with an avidin-beta-galactosidase conjugate. This conjugate was administered to the mice in vivo, followed by AM-TG-betaGal, and subsequent ex vivo fluorescence imaging clearly visualized intraperitoneal tumors as small as 200 microm. This strategy has potential clinical application, for example, in video-assisted laparoscopic tumor resection. 相似文献