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991.
A new terthiophene based ligand (L = 3-(2-pryridyl)-5-(2,2′:5′,2″-terthien-3′-yl) pyrazole was synthesized. The reaction of Ni(BF4)2·6H2O, L and nBu4N[Fe(CN)3tp∗] (tp∗ = tris(3,5-dimethylpyrazol-1-yl)borohyrdide) with NaBPh4 in MeOH/acetone yielded a cyanide bridged tetranuclear complex [Fe2Ni2(CN)6(tp∗)2(L)4](BPh4)2 (1). The electrochemical properties of both 1 and L were investigated, and magnetic susceptibility measurements of 1 were conducted, revealing that ferromagnetic interactions were operative within the tetranuclear core. 相似文献
992.
In this paper, we describe a method to enhance the fluorescence signal of mutagen detection using SOS response-induced green fluorescence protein (GFP) in genetically modified Escherichia coli using a multi-layered substrate. To generate E. coli that express SOS response-induced GFP, we constructed a plasmid carrying the RecA promoter located upstream of the GFP gene and used it to transform E. coli BL21. The transformed strain was incubated with mitomycin C (MMC), a typical mutagen, and then immobilized on a multi-layered substrate with Ag and a thin Al(2)O(3) layer on a glass slide. Since the multi-layered substrate technique is an optical technique with potential to enhance the fluorescence of fluorophore placed on top of the substrate, the multi-layered substrate was expected to improve the fluorescence signal of mutagen detection. We obtained an average 14-fold fluorescence enhancement of MMC-induced GFP in the concentration range 1 to 1000 ng/ml. In addition, the lower detection limit of MMC was improved using this technique, and was estimated to be 1 ng/ml because of an enlargement of the difference between the blank and the signal of 1 ng/ml of MMC. 相似文献
993.
Matsumori N Tanada N Nozu K Okazaki H Oishi T Murata M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(31):8568-8575
A lipid raft is a cholesterol (Chol)-rich microdomain floating in a sea of lipid bilayers. Although Chol is thought to interact preferentially with sphingolipids such as sphingomyelin (SM), rather than with glycerophospholipids, the origin of the specific interaction has remained unresolved, primarily because of the high mobility of lipid molecules and weak intermolecular interactions. In this study, we synthesized SM-Chol conjugates with functionally designed linker portions to restrain Chol mobility and examined their formation of ordered membranes by a detergent insolubility assay, fluorescence anisotropy experiments, and fluorescence-quenching assay. In all of the tests, membranes prepared from the conjugates showed properties of ordered domains comparable to a SM-Chol (1:1) membrane. To gain insight into the structure of bilayers composed from the conjugates, we performed molecular dynamics simulations with 64 molecules of the conjugates, which suggested that the conjugates form a stable bilayer structure by bending at the linker portion and, mostly, reproduce the hydrogen bonds between the SM and Chol portions. These results imply that the molecular recognition between SM and Chol in an ordered domain is essentially reproduced by the conjugated molecules and, thus, demonstrates that these conjugate molecules could potentially serve as molecular probes for understanding molecular recognition in lipid rafts. 相似文献
994.
Oshige M Kawasaki S Takano H Yamaguchi K Kurita H Mizuno T Matsuura S Mizuno A Katsura S 《Journal of fluorescence》2011,21(3):1189-1194
Direct observation studies of single molecules have revealed molecular behaviors usually hidden in the ensemble and time-averaging
of bulk experiments. Direct single DNA molecule analysis of DNA metabolism reactions such as DNA replication, repair, and
recombination is necessary to fully understand these essential processes. Intercalation of fluorescent dyes such as YOYO-1
and SYTOX Orange has been the standard method for observing single molecules of double-stranded DNA (dsDNA), but effective
fluorescent dyes for observing single molecules of single-stranded DNA (ssDNA) have not been found. To facilitate direct single-molecule
observations of DNA metabolism reactions, it is necessary to establish methods for discriminating ssDNA and dsDNA. To observe
ssDNA directly, we prepared a fusion protein consisting of the 70 kDa DNA-binding domain of replication protein A and enhanced
yellow fluorescent protein (RPA-YFP). This fusion protein had ssDNA-binding activity. In our experiments, dsDNA was stained
by SYTOX Orange and ssDNA by RPA-YFP, and we succeeded in staining ssDNA and dsDNA by using RPA-YFP and SYTOX Orange simultaneously. 相似文献
995.
Yoshifumi Sasano Hiroki Tanaka Yohei Haketa Yoichi Kobayashi Yukihide Ishibashi Tatsuki Morimoto Ryuma Sato Yasuteru Shigeta Nobuhiro Yasuda Tsuyoshi Asahi Hiromitsu Maeda 《Chemical science》2021,12(28):9645
In this study, charged π-electronic species are observed to develop stacking structures based on electrostatic and dispersion forces. iπ–iπ Interaction, defined herein, functions for the stacking structures consisting of charged π-electronic species and is in contrast to conventional π–π interaction, which mainly exhibits dispersion force, for electronically neutral π-electronic species. Establishing the concept of iπ–iπ interaction requires the evaluation of interionic interactions for π-electronic ion pairs. Free base (metal-free) and diamagnetic metal complexes of 5-hydroxy-10,15,20-tris(pentafluorophenyl)porphyrin were synthesized, producing π-electronic anions upon the deprotonation of the hydroxy unit. Coexisting cations in the ion pairs with porphyrin anions were introduced as the counter species of the hydroxy anion as a base for commercially available cations and as ion-exchanged species, via Na+ in the intermediate ion pairs, for synthesized π-electronic cations. Solid-state ion-pairing assemblies were constructed for the porphyrin anions in combination with aliphatic tetrabutylammonium (TBA+) and π-electronic 4,8,12-tripropyl-4,8,12-triazatriangulenium (TATA+) cations. The ordered arrangements of charged species, with the contributions of the charge-by-charge and charge-segregated modes, were observed according to the constituent charged building units. The energy decomposition analysis (EDA) of single-crystal packing structures revealed that electrostatic and dispersion forces are important factors in stabilizing the stacking of π-electronic ions. Furthermore, crystal-state absorption spectra of the ion pairs were correlated with the assembling modes. Transient absorption spectroscopy of the single crystals revealed the occurrence of photoinduced electron transfer from the π-electronic anion in the charge-segregated mode.π-Electronic ion pairs comprising porphyrin-based π-electronic anions have exhibited characteristic assembling modes and resulting electronic properties such as solid-state absorption and photoinduced electron transfer. 相似文献
996.
997.
Takayoshi Yamamoto Hiroshi Okuda Kohki Takeshita Noritaka Usami Yoshinori Kitajima Hiroki Ogawa 《Journal of synchrotron radiation》2014,21(1):161-164
Grazing‐incidence small‐angle X‐ray scattering (GISAXS) measurements with soft X‐rays have been applied to Ge nanodots capped with a Si layer. Spatially anisotropic distribution of nanodots resulted in strongly asymmetric GISAXS patterns in the qy direction in the soft X‐ray region, which have not been observed with conventional hard X‐rays. However, such apparent differences were explained by performing a GISAXS intensity calculation on the Ewald sphere, i.e. taking the curvature of Ewald sphere into account. 相似文献
998.
Takehito Suzuki Hiroki Yonamine Takuya Konno John C. Young Kotaro Murai Fumiaki Miyamaru Keisuke Takano Hideaki Kitahara Masanori Hangyo 《Applied Physics A: Materials Science & Processing》2014,115(2):495-500
This paper presents a three-dimensional concave lens constructed from a metallic slit array. The effective refractive index is estimated to be $0<n<1$ . The actual lens requires spacers in the slits. A lens using a low loss dielectric material for the terahertz frequency band is designed. The fast wave effect is enhanced in order to mitigate the slow wave effect of the dielectric material. Full wave analysis results are obtained by ANSYS HFSS and the focusing effect of the three-dimensional concave lens is confirmed in the terahertz frequency band. 相似文献
999.
A configuration of points and lines is cyclic if it has an automorphism that permutes its points in a full cycle. A closed formula is derived for the number of nonisomorphic connected cyclic configurations of type (v3), i.e. which have v points and lines, and each point/line is incident with exactly three lines/points. In addition, a Bays–Lambossy type theorem is proved for cyclic configurations if the number of points is a product of two primes or a prime power. 相似文献
1000.
Yoshinori Namihira Jingjing Liu Taito Koga Feroza Begum Md. Anwar Hossain Nianyu Zou Shubi F. Kaijage Yuki Hirako Hiroki Higa Md. Asraful Islam 《Optical Review》2011,18(6):436-440
This paper presents a highly nonlinear octagonal photonic crystal fiber (HN-OPCF) with a Ge-doped core for dental optical
coherence tomography (OCT) applications. The simulation results show that a nonlinear coefficient of 56.3W−1 km−1 and the flattened dispersion of less than −1:0 ps/(nm·km) are obtained in 75 nm waveband (1265–1340 nm). Owing to its high
nonlinear coefficient and flattened dispersion, the HN-OPCF is expected to be suitable for supercontinuum generation, which
is very important in OCT applications. The numerical simulation results demonstrate that the proposed HN-OPCF can generate
wideband supercontinuum. 相似文献