Kwansei Gakuin University

The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.

Ultrapure blue-fluorescent molecules based on thermally activated delayed fluorescence are developed. Organic light-emitting diode (OLED) devices employing the new emitters exhibit a deep blue emission at 467 nm with a full-width at half-maximum of 28 nm, CIE coordinates of (0.12, 0.13), and an internal quantum efficiency of ≈100%, which represent record-setting performance for blue OLED devices. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

The vertebrate gene repertoire is characterized by "cryptic" genes whose identification has been hampered by their absence from the genomes of well-studied species. One example is the Bmp16 gene, a paralog of the developmental key genes Bmp2 and -4. We focus on the Bmp2/4/16 group of genes to study the evolutionary dynamics following gen(om)e duplications with special emphasis on the poorly studied Bmp16 gene. We reveal the presence of Bmp16 in chondrichthyans in addition to previously reported teleost fishes and reptiles. Using comprehensive, vertebrate-wide gene sampling, our phylogenetic analysis complemented with synteny analyses suggests that Bmp2, -4 and -16 are remnants of a gene quartet that originated during the two rounds of whole-genome duplication (2R-WGD) early in vertebrate evolution. We confirm that Bmp16 genes were lost independently in at least three lineages (mammals, archelosaurs and amphibians) and report that they have elevated rates of sequence evolution. This finding agrees with their more "flexible" deployment during development; while Bmp16 has limited embryonic expression domains in the cloudy catshark, it is broadly expressed in the green anole lizard. Our study illustrates the dynamics of gene family evolution by integrating insights from sequence diversification, gene repertoire changes, and shuffling of expression domains.

Measurement of the quantum-mechanical phase in quantum matter provides the most direct manifestation of the underlying abstract physics. We used resonant x-ray scattering to probe the relative phases of constituent atomic orbitals in an electronic wave function, which uncovers the unconventional Mott insulating state induced by relativistic spin-orbit coupling in the layered 5d transition metal oxide Sr2IrO4. A selection rule based on intra-atomic interference effects establishes a complex spin-orbital state represented by an effective total angular momentum = 1/2 quantum number, the phase of which can lead to a quantum topological state of matter.

Publisher Summary Generalized two-dimensional (2D) correlation spectroscopy is described to show how this technique can be applied to a very broad range of spectral analysis problems. In this spectroscopy, the underlying similarity or dissimilarity among systematic variations in spectroscopic signal intensities is examined. It develops parallel to multiple pulse-based 2D spectroscopy techniques and employs a somewhat different approach to constructing 2D spectra. The signal variations are induced by an external perturbation or physical stimulus applied to the sample, and the pattern of the intensity variation is systematically analyzed by a simple cross-correlation technique. The correlation intensities thus obtained are displayed in the form of a 2D map defined by two independent spectral axes for further analysis. Such a 2D map is referred to as a 2D correlation spectrum, even though many of today's 2D correlation studies include applications in the field outside of spectroscopy, such as chromatography and microscopy. An illustrative example is given for the analysis of attenuated total reflection (ATR) IR spectra collected during the crystallization of biodegradable polymer poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) to demonstrate the merits of this technique, such as the enhancement of spectral resolution, detection of coordinated changes among spectral signals, and determination of relative directions and sequential order of intensity variations.

ADVERTISEMENT RETURN TO ISSUEPREVArticleUltrafast Dynamics of Photochromic SystemsNaoto Tamai and Hiroshi MiyasakaView Author Information Department of Chemistry, Faculty of Science, Kwansei Gakuin University, Uegahara, Nishinomiya, Hyogo 660-8581, Japan, Department of Polymer Science and Engineering, Kyoto Institute of Technology, and CREST, Japan Science and Technology Corporation, Matsugasaki, Sakyo, Kyoto 606-8585, Japan Cite this: Chem. Rev. 2000, 100, 5, 1875–1890Publication Date (Web):March 7, 2000Publication History Received6 July 1999Published online7 March 2000Published inissue 1 May 2000https://pubs.acs.org/doi/10.1021/cr9800816https://doi.org/10.1021/cr9800816research-articleACS PublicationsCopyright © 2000 American Chemical SocietyRequest reuse permissionsArticle Views9442Altmetric-Citations757LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Absorption,Fluorescence,Isomerization,Lasers,Light absorption Get e-Alerts

One-shot double, triple, and quadruple borylation reactions of triarylamines were developed through a judicious choice of boron source and Brønsted base. With the aid of borylation reactions, a variety of BN-doped nanographenes were synthesized in two steps from commercially available starting materials. An organic light-emitting diode device employing BN-doped nanographene as an emitter exhibited deep pure-blue emission at 460 nm, with CIE coordinates of (0.13, 0.11), and an external quantum efficiency of 18.3%.

Fourier-transform infrared (FT-IR), near-infrared (NIR)-excited FT-Raman, and FT-NIR spectra have been measured for poly(acrylic acid) (PAA) in a cast film over a temperature range of 40−140 °C, to investigate structures of hydrogen bonds and their dissociation. The CO stretching bands in the FT-IR spectra are unraveled by a prevalent multiple species model for small aliphatic acids with various kinds of associated forms of carboxylic acid groups, namely cyclic dimer, linearly associated oligomers of COOH, and free COOH groups. These different structures of hydrogen bond persist even when the temperature rises well above the glass transition temperature. The FT-Raman spectra confirm the existence of such COOH groups. Temperature-dependent intensity changes in the first overtone of an OH stretching mode of PAA reveal that the COOH groups dissociate significantly at high temperatures. We propose that the coexistence of various possible hydrogen-bond forms analogous to those in small aliphatic acids best interprets the vibrational spectral features of PAA. The oligomeric chains of COOH groups in PAA may explain the previously proposed cooperative hydrogen bond in PAA or polymer blends containing PAA.

Surface-enhanced Raman scattering (SERS) and tip-enhanced Raman scattering (TERS) have opened a variety of exciting research fields. However, although a vast number of applications have been proposed since the two techniques were first reported, none has been applied to real practical use. This calls for an update in the recent fundamental and application studies of SERS and TERS. Thus, the goals and scope of this review are to report new directions and perspectives of SERS and TERS, mainly from the viewpoint of combining their mechanism and application studies. Regarding the recent progress in SERS and TERS, this review discusses four main topics: (1) nanometer to subnanometer plasmonic hotspots for SERS; (2) Ångström resolved TERS; (3) chemical mechanisms, i.e., charge-transfer mechanism of SERS and semiconductor-enhanced Raman scattering; and (4) the creation of a strong bridge between the mechanism studies and applications.

The development of a one-step borylation of 1,3-diaryloxybenzenes, yielding novel boron-containing polycyclic aromatic compounds, is reported. The resulting boron-containing compounds possess high singlet-triplet excitation energies as a result of localized frontier molecular orbitals induced by boron and oxygen. Using these compounds as a host material, we successfully prepared phosphorescent organic light-emitting diodes exhibiting high efficiency and adequate lifetimes. Moreover, using the present one-step borylation, we succeeded in the synthesis of an efficient, thermally activated delayed fluorescence emitter and boron-fused benzo[6]helicene.

A series of fluorophores with single-exponential fluorescence decays in liquid solution at 20 degrees C were measured independently by nine laboratories using single-photon timing and multifrequency phase and modulation fluorometry instruments with lasers as excitation source. The dyes that can serve as fluorescence lifetime standards for time-domain and frequency-domain measurements are all commercially available, are photostable under the conditions of the measurements, and are soluble in solvents of spectroscopic quality (methanol, cyclohexane, water). These lifetime standards are anthracene, 9-cyanoanthracene, 9,10-diphenylanthracene, N-methylcarbazole, coumarin 153, erythrosin B, N-acetyl-l-tryptophanamide, 1,4-bis(5-phenyloxazol-2-yl)benzene, 2,5-diphenyloxazole, rhodamine B, rubrene, N-(3-sulfopropyl)acridinium, and 1,4-diphenylbenzene. At 20 degrees C, the fluorescence lifetimes vary from 89 ps to 31.2 ns, depending on fluorescent dye and solvent, which is a useful range for modern pico- and nanosecond time-domain or mega- to gigahertz frequency-domain instrumentation. The decay times are independent of the excitation and emission wavelengths. Dependent on the structure of the dye and the solvent, the excitation wavelengths used range from 284 to 575 nm, the emission from 330 to 630 nm. These lifetime standards may be used to either calibrate or test the resolution of time- and frequency-domain instrumentation or as reference compounds to eliminate the color effect in photomultiplier tubes. Statistical analyses by means of two-sample charts indicate that there is no laboratory bias in the lifetime determinations. Moreover, statistical tests show that there is an excellent correlation between the lifetimes estimated by the time-domain and frequency-domain fluorometries. Comprehensive tables compiling the results for 20 (fluorescence lifetime standard/solvent) combinations are given.

We present a two-dimensional (2D) lattice model that exhibits a nontrivial topological phase in the absence of the Berry curvature. Instead, the Berry connection provides the topological nontrivial phase in the model, whose integration over the momentum space, the so-called 2D Zak phase, yields a fractional wave polarization in each direction. These fractional wave polarizations manifest themselves as degenerated edge states with opposite parities in the model.

A new wavelength interval selection procedure, moving window partial least-squares regression (MWPLSR), is proposed for multicomponent spectral analysis. This procedure builds a series of PLS models in a window that moves over the whole spectral region and then locates useful spectral intervals in terms of the least complexity of PLS models reaching a desired error level. Based on a proposed theory demonstrating the necessity of wavelength selection, it is shown that MWPLSR provides a viable approach to eliminate the extra variability generated by non-composition-related factors such as the perturbations in experimental conditions and physical properties of samples. A salient advantage of MWPLSR is that the calibration model is very stable against the interference from non-composition-related factors. Moreover, the selection of spectral intervals in terms of the least model complexity enables the reduction of the size of a calibration sample set in calibration modeling. Two strategies are suggested for coupling the MWPLSR procedure with PLS for multicomponent spectral analysis: One is the inclusion of all selected intervals to develop a PLS calibration model, and the other is the combination of the PLS models built separately in each interval. The combination of multiple PLS models offers a novel potential tool for improving the performance of individual models. The proposed procedures are evaluated using two open-path Fourier transform infrared data sets and one near-infrared data set, each having different noise characteristics. The results reveal that the proposed procedures are very promising for vibrational spectroscopy-based multicomponent analyses and give much better prediction than the full-spectrum PLS modeling.

Photochromic reactions of diarylethene derivatives were detected at a single-molecule level by using a fluorescence technique. Fluorescent photoswitching molecules in which photochromic diarylethene and fluorescent bis(phenylethynyl)anthracene units are linked through an adamantyl spacer were synthesized, and switching of fluorescence upon irradiation with UV and visible light was followed in solution as well as on polymer films at the single-molecule level. Although in solution the fluorescence intensity gradually changed upon irradiation with UV and visible light, digital on/off switching between two discrete states was observed at the single-molecule level. The "on"- and "off"-times were dependent on the power of UV and visible light. When the power of UV and visible light was increased, the average on- and off-times became short in proportion to the reciprocal power of the light. The response-times were found to show distribution. The distribution of the on- and off-times is considered to reflect the difference in the micro-environment as well as conformation of the molecules.

The genus Thermococcus, comprised of sulfur-reducing hyperthermophilic archaea, belongs to the order Thermococcales in Euryarchaeota along with the closely related genus Pyrococcus. The members of Thermococcus are ubiquitously present in natural high-temperature environments, and are therefore considered to play a major role in the ecology and metabolic activity of microbial consortia within hot-water ecosystems. To obtain insight into this important genus, we have determined and annotated the complete 2,088,737-base genome of Thermococcus kodakaraensis strain KOD1, followed by a comparison with the three complete genomes of Pyrococcus spp. A total of 2306 coding DNA sequences (CDSs) have been identified, among which half (1165 CDSs) are annotatable, whereas the functions of 41% (936 CDSs) cannot be predicted from the primary structures. The genome contains seven genes for probable transposases and four virus-related regions. Several proteins within these genetic elements show high similarities to those in Pyrococcus spp., implying the natural occurrence of horizontal gene transfer of such mobile elements among the order Thermococcales. Comparative genomics clarified that 1204 proteins, including those for information processing and basic metabolisms, are shared among T. kodakaraensis and the three Pyrococcus spp. On the other hand, among the set of 689 proteins unique to T. kodakaraensis, there are several intriguing proteins that might be responsible for the specific trait of the genus Thermococcus, such as proteins involved in additional pyruvate oxidation, nucleotide metabolisms, unique or additional metal ion transporters, improved stress response system, and a distinct restriction system.

Surface-enhanced Raman scattering (SERS)-active nanomaterials have extended from noble metals and transition metals to semiconductor materials, since the first discovery of SERS in the mid-1970s. In comparison with metal substrates and transition metals, semiconductor materials have additional optical and electrical properties besides SERS enhancement ability, which enable them to display remarkable charge-transfer enhancement and catalytic ability. Moreover, their superior biocompatibility allows these nanomaterials to have great potential applications in bioscience. Herein we highlight the fast growing research field focusing on SERS-active semiconductor nanomaterials and semiconductor-other material heterostructures developed in our group as well as in other related research studies. The material size, morphology and assembly-dependent SERS enhancement have been discussed in detail. Furthermore, a variety of promising applications of semiconductor-enhanced Raman scattering in photoelectric characterization, redox biochemistry, sensing, and the catalytic degradation of organic pollutants are introduced.

The nature of the "peculiarly strong" interaction between the poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) chains was investigated by real time infrared spectroscopy during the isothermal melt crystallization process of the PLLA/PDLA stereocomplex. A very small low-frequency shift (about 1 cm-1) of νas(CH3) and a larger low-frequency shift (about 5 cm-1) of ν(CO) were observed. The typical butterfly pattern in the two-dimensional (2D) asynchronous correlation spectrum and the second-derivative spectra reveal that there is a "peak shift" for ν(CO). The red shifts of the stretching vibration modes of the methyl and carbonyl groups suggest that the interaction between the PLLA/PDLA stereocomplex is ascribed to CH3···OC hydrogen bonding. Another interesting result is that the peak shift of the ν(CO) band already occurs in the induction period, which indicates that the CH3···OC interaction is the driving force for forming the racemic nucleation of the PLLA/PDLA stereocomplex. Moreover, the 2D correlation analysis indicates that the structural adjustment of the CH3 group occurs prior to that of the C−O−C backbone during the stereocomplexation process of PLLA/PDLA. The CH3···OC interaction may be the reason for this sequence of structural changes.

This study examined the factor structure of the Self-Compassion Scale (SCS) using secondary data drawn from 20 samples (N = 11,685)-7 English and 13 non-English-including 10 community, 6 student, 1 mixed community/student, 1 meditator, and 2 clinical samples. Self-compassion is theorized to represent a system with 6 constituent components: self-kindness, common humanity, mindfulness and reduced self-judgment, isolation and overidentification. There has been controversy as to whether a total score on the SCS or if separate scores representing compassionate versus uncompassionate self-responding should be used. The current study examined the factor structure of the SCS using confirmatory factor analyses (CFA) and Exploratory Structural Equation Modeling (ESEM) to examine 5 distinct models: 1-factor, 2-factor correlated, 6-factor correlated, single-bifactor (1 general self-compassion factor and 6 group factors), and 2-bifactor models (2 correlated general factors each with 3 group factors representing compassionate or uncompassionate self-responding). Results indicated that a 1- and 2-factor solution to the SCS had inadequate fit in every sample examined using both CFA and ESEM, whereas fit was excellent using ESEM for the 6-factor correlated, single-bifactor and correlated 2-bifactor models. However, factor loadings for the correlated 2-bifactor models indicated that 2 separate factors were not well specified. A general factor explained 95% of the reliable item variance in the single-bifactor model. Results support use of the SCS to examine 6 subscale scores (representing the constituent components of self-compassion) or a total score (representing overall self-compassion), but not separate scores representing compassionate and uncompassionate self-responding. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Abstract Thermally activated delayed fluorescence (TADF) materials based on the multiple resonance (MR) effect are applied in organic light‐emitting diodes (OLEDs), combining high color purity and efficiency. However, they are not fabricated via solution‐processing, which is an economical approach toward the mass production of OLED displays. Here, a solution‐processable MR‐TADF material (OAB‐ABP‐1), with an extended π‐skeleton and bulky substituents, is designed. OAB‐ABP‐1 is synthesized from commercially available starting materials via a four‐step process involving one‐shot double borylation. OAB‐ABP‐1 presents attractive photophysical properties, a narrow emission band, a high photoluminescence quantum yield, a small energy gap between S 1 and T 1 , and low activation energy for reverse intersystem crossing. These properties are attributed to the alternating localization of the highest occupied and lowest unoccupied molecular orbitals induced by the boron, nitrogen, and oxygen atoms. Furthermore, to facilitate charge recombination, two novel semiconducting polymers with similar ionization potentials to that of OAB‐ABP‐1 are synthesized for use as interlayer and emissive layer materials. A solution‐processed OLED device is fabricated using OAB‐ABP‐1 and the aforementioned polymers; it exhibits pure green electroluminescence with a small full‐width at half‐maximum and a high external quantum efficiency with minimum efficiency roll‐off.

The emission process of the o-carborane dyad with anthracene originating from the twisted intramolecular charge transfer (TICT) state in the crystalline state is described. The anthracene-o-carborane dyad was synthesized and its optical properties were investigated. Initially, the dyad had aggregation- and crystallization-induced emission enhancement (AIEE and CIEE) properties via the intramolecular charge transfer (ICT) state. Interestingly, the dyad presented the dual-emissions assigned to both locally excited (LE) and ICT states in solution. From the mechanistic studies and computer calculations, it was indicated that the emission band from the ICT should be attributable to the TICT emission. Surprisingly, even in the crystalline state, the TICT emission was observed. It was proposed from that the compact sphere shape of o-carborane would allow for rotation even in the condensed state.