S U M M A R YW e propose a new method for the simultaneous measurement of P -and S-wave attentuation by extending the conventional coda-normalization method which had been limited to the estimation of S-wave attenuation. Using this method, we measured frequency-dependent attenuation of both P a n d S waves in the lithosphere beneath the Kanto area, Japan, from seismograms of 174 local earthquakes for the frequency range 1.5 5 f 5 24 Hz. T h e values of Q;' and Q;' corresponding t o peak amplitude decays show strong frequency dependence, a n d are expressed by using power laws Q,' = 0.012f-')73 and Qp' = 0.031f~0Y5, respectively. T h e ratio Qp'/Q.;' is found t o be larger than unity for the whole frequency range. The apparent attenuations of P and S waves with travel distance are almost the same for frequencies higher than 1 Hz. Our results differ from the characteristics of low-frequency wave attenuation reported by other studies for frequencies lower than 1 Hz. This frequency dependence and the ratio may suggest that scattering loss due t o random heterogeneities in the earth medium plays an important role in seismic-wave attenuation in the lithosphere.

Our improved CRISPR-Cas9-based photoactivatable transcription systems, CPTS2.0 and Split-CPTS2.0, enable high blue-light-inducible activation of endogenous target genes in various human cell lines. We achieved reversible activation of target genes with CPTS2.0 and induced neuronal differentiation in induced pluripotent stem cells (iPSCs) by upregulating NEUROD1 with Split-CPTS2.0.

In this review, we introduce two kinds of bio-related nanoarchitectonics, DNA nanoarchitectonics and cellmacromolecular nanoarchitectonics, both of which are basically controlled by chemical strategies. The former DNA-based approach would represent the precise nature of the nanoarchitectonics based on the strict or "digital" molecular recognition between nucleic bases. This part includes functionalization of single DNAs by chemical means, modification of the main-chain or side-chain bases to achieve stronger DNA binding, DNA aptamers and DNAzymes. It also includes programmable assemblies of DNAs (DNA Origami) and their applications for delivery of drugs to target sites in vivo, sensing in vivo, and selective labeling of biomaterials in cells and in animals. In contrast to the digital molecular recognition between nucleic bases, cell membrane assemblies and their interaction with macromolecules are achieved through rather generic and "analog" interactions such as hydrophobic effects and electrostatic forces. This cell-macromolecular nanoarchitectonics is discussed in the latter part of this review. This part includes bottom-up and top-down approaches for constructing highly organized cell-architectures with macromolecules, for regulating cell adhesion pattern and their functions in twodimension, for generating three-dimensional cell architectures on micro-patterned surfaces, and for building synthetic/natural macromolecular modified hybrid biointerfaces.

Nucleobase recognition in water is successfully achieved by the use of an abasic site (AP site) as the molecular recognition field. We intentionally construct the AP site in DNA duplex so as to orient the AP site toward a target nucleobase and examine the complexation of 2-amino-7-methylnaphthyridine (AMND) with nucleobases at the AP site. AMND is found to selectively bind to cytosine (C) base with a 1:1 binding constant of >106 M-1, accompanied by remarkable quenching of its fluorescence. In addition to hydrogen bonding, a stacking interaction with nucleobases flanking the AP site seems responsible for the binding properties of AMND at the AP site. Possible use of AMND is also presented for selective and visible detection of a single-base alternation related to the cytosine base.

Abstract. The analysis of the seismogram coda envelopes of local and regional earthquakes is one of the most effective strategies for investigating the heterogeneous lithospheric structure characterized by the seismic scattering and attenuation. In order to synthesize the coda envelope we introduce a numerical scheme called the direct simulation Monte Carlo method, which has been used in the field of the kinetic theory of gases. Because of the simplicity of the algorithm the method has several advantages over previous methods in terms of the flexibility of the numerical calculation to incorporate various factors required to construct realistic seismogram envelopes. On the basis of coda envelope simulations, including multiple scattering, we show that an increase of seismic velocity with depth severely affects the shape of the coda envelope. The effects of ray bending due to the velocity increase at the Moho and the reflection at the free surface are clearly found in the synthesized envelope for a shallow earthquake. Our simulation demonstrates that the amplitude of the envelope is magnified by stagnation of seismic energy at shallow depths due to the positive velocity gradient with depth. Because of this effect, for an a priori assumption of a homogeneous velocity model the measurement of the scattering coefficient by conventional methods may be overestimated. IntroductionCoda waves of local and regional earthquakes are consid- lopes of local earthquakes it is necessary to trace the ray paths of seismic waves in three dimensions by using a realistic velocity structure model. The Monte Carlo method plays an important role in investigating the effect of velocity structure on coda envelopes. Adopting an analytical integral representation for the distance between scattering points, Hoshiba [1997] developed an efficient algorithm for a simple structure model and studied the characteristics of coda envelopes in layered media. In order to calculate seismogram envelopes for a realistic Earth model in which seismic velocity varies complexly we introduce a direct simulation Monte Carlo (DSMC) method, which has been used in the field of the kinetic theory of gases [e.g., Bird, 1976Bird, , 1994Bellomo, 1995]. The DSMC method, which utilizes a finite difference scheme for ray tracing, has an advantage over previous methods in terms of flexibility and can be applied to three-dimensional (3-D) (i.e., laterally varying) velocity structures. In this paper, we synthesize seismogram envelopes for a shallow local earthquake using a realistic velocity structure. Instead of the layered structures which were used by Hoshiba [1997] and Margetin et al.[1998], we adopt a lithospheric model with a positive velocity gradient with depth to evaluate the effect of seismic ray bending on coda envelopes. MethodWe apply the DSMC method to synthesize seismogram envelopes in 3-D scattering media. The treatment of seismic waves is completely acoustic in this paper (i.e., only S waves are considered acoustically). For simplicity, let us suppose a 3...

A novel water-soluble, biocompatible polymer, poly(ethylene glycol)-block-poly((2-N,N-dimethylamino)ethyl methacrylate) (PEG-b-PAMA), possessing controlled molecular weight with a narrow molecular weight distribution, was synthesized by the atom-transfer radical polymerization (ATRP) method. PEG-b-PAMA having a short PAMA chain length was successfully synthesized under suitable polymerization conditions. Gold nanoparticles (GNPs) were modified using PEG-b-PAMA prepared under a variety of PEGylation conditions. Under alkaline conditions (pH >10) and an [N]/[GNP] ratio of more than 3300, the PEGylated GNPs (PEG-GNPs) showed complete dispersion stability, avoiding coagulation. The amino groups of the PAMA segment of the block copolymers were completely deprotonated above pH 10. This means that PEG-b-PAMA interacted with the GNP surface via multipoint coordination of the tertiary amino groups of PAMA, not electrostatically. The effect of the number of amino groups in the PAMA segment on GNP surface modifications was investigated by zeta potential and dynamic light scattering (DLS) measurements. When the PEG-GNPs were prepared in excess polymer solution, almost the same diameter was observed regardless of the PAMA chain length. After the PEG-GNPs were purified by centrifugation, the zeta potentials of all PEG-GNPs were shielded to almost 0 mV, indicating the effective modifications of the GNP surface by PEG-b-PAMA regardless of the chain length. However, the particle size and particle size distribution of the purified PEG-GNPs were strongly affected by the PAMA chain length. PEG-GNPs with longer PAMA segments underwent coagulation after purification, whereas PEG-GNPs with shorter PAMA segments increased their dispersion stability. The experimental results of the thermal gravimetric analysis confirmed that the PEG density on the GNP surface increased as the AMA units decreased to 3. Thus, the dispersion stability depended significantly on the PEG density on the GNP surface. GNPs modified with PEG-b-PAMA having short AMA units showed excellent dispersion stability under a variety of pH conditions. The excellent dispersion stability of the obtained PEG-GNP was also confirmed both in bovine serum albumin (BSA) solution and 95% human serum.

Here, we report on a significant effect of substitutions on the binding affinity of a series of 2-amino-1,8-naphthyridines, i.e., 2-amino-1,8-naphthyridine (AND), 2-amino-7-methyl-1,8-naphthyridine (AMND), 2-amino-5,7-dimethyl-1,8-naphthyridine (ADMND) and 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND), all of which can bind to cytosine opposite an AP site in DNA duplexes. Fluorescence titration experiments show that the binding affinity for cytosine is effectively enhanced by the introduction of methyl groups to the naphthyridine ring, and the 1:1 binding constant (106 M−1) follows in the order of AND (0.30) < AMND (2.7) < ADMND (6.1) < ATMND (19) in solutions containing 110 mM Na+ (pH 7.0, at 20°C). The thermodynamic parameters obtained by isothermal titration calorimetry experiments indicate that the introduction of methyl groups effectively reduces the loss of binding entropy, which is indeed responsible for the increase in the binding affinity. The heat capacity change (ΔCp), as determined from temperature dependence of the binding enthalpy, is found to be significantly different between AND (−161 cal/mol K) and ATMND (−217 cal/mol K). The hydrophobic contribution appears to be a key force to explain the observed effect of substitutions on the binding affinity when the observed binding free energy (ΔGobs) is dissected into its component terms.

To examine the adsorption behavior of antibody fragments (Fab') directly immobilized on a gold surface through S-Au linkage, analyses by surface plasmon resonance (SPR), fluorometry, and atomic force microscopy (AFM) with an excellent blocking technique by the consecutive treatments of longer-poly(ethylene glycol) (PEG) (MW = 5k) and shorter-PEG (MW = 2k), abbreviated as mixed-PEG layer formation, were performed. The results of the SPR analysis suggest that the adsorption-induced inactivation of the antigen-binding activity of Fab' took place gradually on the gold surface, where the activity disappeared almost completely at 60 min after Fab' immobilization. In contrast, in the case of Fab' coimmobilized by the mixed-PEG layer, 70% of the initial antigen-binding activity of the Fab' was retained even 60 min after the construction of the hybrid surface. Using fluorescein-labeled Fab' (FL-Fab'), fluorescence measurement of the constructed surface was carried out. The fluorescence of the FL-Fab' without any blocking agent on the gold surface was gradually quenched and finally decreased to 40% of the initial intensity 60 min after Fab' immobilization. The decrease in the fluorescence intensity is considered to be caused by the change in the distance between the fluorophores labeled on the Fab' and the gold surface, due to the energy transfer from the fluorophores to the gold surface. In contrast, 75% of the initial intensity was observed on the Fab'/mixed-PEG coimmobilized surface. The results obtained from the SPR and fluorometric analyses correlated well with each other; thus, the surface-induced inactivation of the antigen-binding functionality was presumably due to the conformational and/or orientation change of Fab' on the gold surface. AFM studies provided direct information on the time-dependent decrease in the height of the immobilized Fab' on the gold surface. In contrast, the coimmobilization of densely packed mixed-PEG tethered chains around the Fab' on the gold surface suppressed the decrease in the height of Fab', presumably indicating that the conformational and/or orientation change of Fab' was suppressed by the coimmobilized mixed-PEG layer. The new findings obtained in this study are expected to be useful for the improvement of the antibody fragment method and, thus, for the construction of high-performance immuno-surfaces.