Ultrafine Spatial Modulation of Diazapyrene-Based Two-Dimensional Conjugated Covalent Organic Frameworks.

Tailormade bottom-up synthesis of covalent organic frameworks (COFs) from various functional building blocks offer not only tunable topology and pore size but also multidimensional properties. High crystallinity is one of the prerequisites for their structures and associated physicochemical properties. Among different π-conjugated motifs for constructing COFs, pyrene-based tetragonal structures are effective in achieving highly ordered and crystalline states.

Torsion Angle Analysis of a Thermally Activated Delayed Fluorescence Emitter in an Amorphous State Using Dynamic Nuclear Polarization Enhanced Solid-State NMR.

The torsion angle between donor and acceptor segments of a thermally activated delayed fluorescence (TADF) molecule is one of the most critical factors in determining the performance of TADF-based organic light-emitting diodes (OLEDs) because the torsion angle affects not only the energy gap between the singlet and triplet but also the oscillator strength and spin-orbit coupling. However, the torsion angle is difficult to analyze, because organic molecules are in an amorphous state in OLEDs. Here, we determined the torsion angle of a highly efficient TADF emitter, DACT-II, in an amorphous state by dynamic nuclear polarization enhanced solid-state NMR measurements.

Operando ESR observation in thermally activated delayed fluorescent organic light-emitting diodes.

Organic light-emitting diodes (OLEDs) using thermally activated delayed fluorescence (TADF) materials have advantages over OLEDs using conventional fluorescent materials or high-cost phosphorescent materials, including higher efficiency and lower cost. To attain further high device performance, clarifying internal charge states in OLEDs at a microscopic viewpoint is crucial; however, only a few such studies have been performed. Here, we report a microscopic investigation into internal charge states in OLEDs with a TADF material by electron spin resonance (ESR) at a molecular level.

A Donor-Acceptor 10-Cycloparaphenylene and Its Use as an Emitter in an Organic Light-Emitting Diode.

Here, we explored the possibility of using cycloparaphenylenes (CPP) within a donor-acceptor TADF emitter design. contains four electron-donating moieties connected to a . In the 15 wt % doped in CzSi film, showed sky-blue emission with λ = 475 nm, Φ = 29%, and triexponential emission decays with τ of 4.

Imidazole Acceptor for Both Vacuum-Processable and Solution-Processable Efficient Blue Thermally Activated Delayed Fluorescence.

The members of the imidazole family have been widely used for electron transporting, host, conventional fluorescent, and phosphorescent materials. Although the imidazole core also has great potential as an acceptor segment of deep-blue thermally activated delayed fluorescence (TADF) owing to its high triplet energy, the emission color of imidazole-based TADF organic light-emitting diodes (OLEDs) has so far been limited to blue to green. In this work, four acridan-imidazole systems are theoretically designed aiming for deep- or pure-blue emitters.

Highly Efficient and Stable Blue Organic Light-Emitting Diodes based on Thermally Activated Delayed Fluorophor with Donor-Void-Acceptor Motif.

Thermally activated delayed fluorophores (TADF) with donor-acceptor (D-A) structures always face strong conjugation between donor and acceptor segments, rendering delocalized new molecular orbitals that go against blue emission. Developing TADF emitters with blue colors, high efficiencies, and long lifetimes simultaneously is therefore challenging. Here, a D-void-A structure with D and A moieties connected at the void-position where the frontier orbital from donor and acceptor cannot be distributed, resulting in nonoverlap of the orbitals is proposed.

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode.

In this work we showcase the emitter in which we employed a twin-emitter design of our previously reported material, . This new system presented a red-shifted emission at 488 nm compared to that of at 475 nm and showed a comparable photoluminescence quantum yield of 57.1% in a 20 wt % CzSi film versus 63.

Near-Unity Singlet Fission on a Quantum Dot Initiated by Resonant Energy Transfer.

The conversion of a high-energy photon into two excitons using singlet fission (SF) has stimulated a variety of studies in fields from fundamental physics to device applications. However, efficient SF has only been achieved in limited systems, such as solid crystals and covalent dimers. Here, we established a novel system by assembling 4-(6,13-bis(2-(triisopropylsilyl)ethynyl)pentacen-2-yl)benzoic acid (Pc) chromophores on nanosized CdTe quantum dots (QDs).

Multichromophore Molecular Design for Thermally Activated Delayed-Fluorescence Emitters with Near-Unity Photoluminescence Quantum Yields.

Three multichromophore thermally activated delayed fluorescence (TADF) molecules, , , and , were synthesized and characterized. These molecules were designed by connecting the TADF moiety 4,5-di(9-carbazol-9-yl)phthalonitrile () to different positions of a central benzene ring scaffold. Three highly soluble emitters all exhibited near-quantitative photoluminescence quantum yields (Φ) in toluene.

Exploring the capability of mayenite (12CaO·7AlO) as hydrogen storage material.

We utilized nanoporous mayenite (12CaO·7AlO), a cost-effective material, in the hydride state (H) to explore the possibility of its use for hydrogen storage and transportation. Hydrogen desorption occurs by a simple reaction of mayenite with water, and the nanocage structure transforms into a calcium aluminate hydrate. This reaction enables easy desorption of H ions trapped in the structure, which could allow the use of this material in future portable applications.

Examining simultaneous associations of four emotion regulation strategies with abnormal eating behaviors/attitudes in early adolescents.

Previous research has suggested that emotion regulation strategies (ERSs) are associated with abnormal eating behaviors and attitudes (AEBs). Available data have demonstrated that frequent rumination, a major maladaptive ERS, is associated with elevated AEBs, whereas adaptive ERSs, such as problem-solving and cognitive reappraisal, showed negative associations with AEBs. Most previous studies examined the association of a single ERS with AEBs.

In vivo imaging of dopamine D1 receptor and activated microglia in attention-deficit/hyperactivity disorder: a positron emission tomography study.

Alterations in the cortical dopamine system and microglial activation have been implicated in the pathophysiology of attention-deficit/hyperactivity disorder (ADHD), one of neurodevelopmental disorders that can be conventionally treated with a dopamine enhancer (methylphenidate) albeit unsatisfactorily. Here, we investigated the contributions of the dopamine D1 receptor (D1R) and activated microglia and their interactions to the clinical severities in ADHD individuals using positron emission tomography (PET). Twenty-four psychotropic-naïve ADHD individuals and 24 age- and sex-matched typically developing (TD) subjects underwent PET measurements with [C]SCH23390 for the D1R and [C](R)PK11195 for activated microglia as well as assessments of clinical symptoms and cognitive functions.

Identification of Prime Factors to Maximize the Photocatalytic Hydrogen Evolution of Covalent Organic Frameworks.

Visible-light-driven hydrogen (H) production from water is a promising strategy to convert and store solar energy as chemical energy. Covalent organic frameworks (COFs) are front runners among different classes of organic photocatalysts. The photocatalytic activity of COFs depends on numerous factors such as the electronic band gap, crystallinity, surface area, exciton migration, stability of transient species, charge separation and transport, etc.

Sensory Processing Patterns and Fusiform Activity During Face Processing in Autism Spectrum Disorder.

A growing body of evidence has indicated that individuals with autism spectrum disorder (ASD) exhibit abnormal reactions to sensory stimuli and impaired face processing. Although behavioral studies have reported that individual differences in sensory processing patterns are correlated with performance in face processing tasks, the neural substrates underlying the association between sensory processing patterns and face processing remain unknown. Using functional magnetic resonance imaging, the present study examined the relationships between sensory processing patterns assessed with the Adolescent/Adult Sensory Profile (AASP) and brain activity during a one-back task with two types of stimuli (face or house pictures).

Alterations in serotonin transporter and body image-related cognition in anorexia nervosa.

The serotonin system has been implicated in the pathophysiology of anorexia nervosa (AN). A recent report proposed that body image distortion (BID), a core symptom of AN, may relate to abnormalities of the serotonin system, especially the serotonin transporter (5HTT). Positron emission tomography (PET) studies of underweight patients with active AN reported alterations in serotonin receptors, but not 5HTT.

Thermally Activated Delayed Fluorescent Materials Combining Intra- and Intermolecular Charge Transfers.

A novel thermally activated delayed fluorescent (TADF) compound, 9-(3-((4,6-diphenyl-1,3,5-triazin-2-yl)oxy)phenyl)-3,6-diphenyl-9 H-carbazole (PhCz- o-Trz), with a donor-σ-acceptor (D-σ-A) motif is developed. A flexible small space σ-junction is adopted to partly suppress the intramolecular charge transfer (intra-CT) while inversely enhancing the intermolecular charge transfer (inter-CT) between D/A moieties, realizing the coexistence of both intra-CT and inter-CT in an amorphous aggregate. The coexistence of dual CTs increases the complexity of the singlet and triplet state mixing, enhancing the triplet-to-singlet spin-flip transition and thereby the TADF emission.

Unique Superparamagnetic-like Behavior Observed in Non-π-delocalized Nitroxide Diradical Compounds Showing Discotic Liquid Crystalline Phase.

A unique superparamagnetic-like behavior and a large "positive magneto-LC effect" were observed in the solid phases and the hexagonal columnar (Col ) liquid crystalline (LC) phase, respectively, of novel achiral non-π-delocalized nitroxide diradical compounds (R,S)-1, which showed polymorphism in the solid phases (solids I and II). The SQUID magnetization measurement revealed that (1) (R,S)-1 containing a small amount of racemic diastereomers (R*,R*)-1 possessed an unusual and large temperature-independent magnetic susceptibility (χ >0) component in the original nanocrystalline solid I that was responsible for the observed superparamagnetic-like behavior under low magnetic fields and did not arise from the contamination by extrinsic magnetic metal or metal ion impurities, besides ordinary temperature-dependent paramagnetic susceptibility (χ >0) and temperature-independent diamagnetic susceptibility (χ <0) components, (2) a large increase in molar magnetic susceptibility (χ ) (positive magneto-LC effect) that occurred at the solid I-to-liquid crystal transition upon heating was preserved as an additional χ increase in the resulting polymorphic nanocrystalline solid II by cooling, and (3) such unique magnetic phenomena were induced by thermal processing for (R,S)-1 or by adding a small amount of (R*,R*)-1 to (R,S)-1 as the impurity.

[Participants-centered Design of Annual Meeting: From the Perspectives of Instructional Systems].

　This paper examines the reform experience of the 10th Annual Meeting of the Japanese Society for Pharmaceutical Palliative Care and Sciences from Instructional Systems perspectives, to check whether it was effective, efficient, and appealing for participants. "Instructional Systems" has been a research area in educational technology for the past 50 years, and has also been applied to training and human resource development in healthcare domains. If an annual meeting is to be designed for participants' learning, then perspectives of Instructional Systems can be applied to interpret the effort of the reform.

In vivo Depiction of α7 Nicotinic Receptor Loss for Cognitive Decline in Alzheimer's Disease.

Background: The α7 subtype of the nicotinic acetylcholine receptor (nAChR) is considered important in higher cognitive functions, and cholinergic loss underpins the pathophysiology of Alzheimer's disease (AD). However, the relationships between α7 nAChR function and clinical functions or amyloid-β (Aβ) deposition remain to be explored in the living AD brain.

Objective: We aimed to elucidate the relationship between α7 nAChR availability in the specific cholinergic region and cognitive decline in the Aβ-confirmed AD brain.

Association studies of WD repeat domain 3 and chitobiosyldiphosphodolichol beta-mannosyltransferase genes with schizophrenia in a Japanese population.

Schizophrenia and schizophrenia-like symptoms induced by the dopamine agonists and N-methyl-D aspartate type glutamate receptor antagonists occur only after the adolescent period. Similarly, animal models of schizophrenia by these drugs are also induced after the critical period around postnatal week three. Based upon the development-dependent onsets of these psychotomimetic effects, by using a DNA microarray technique, we identified the WD repeat domain 3 (WDR3) and chitobiosyldiphosphodolichol beta-mannosyltransferase (ALG1) genes as novel candidates for schizophrenia-related molecules, whose mRNAs were up-regulated in the adult (postnatal week seven), but not in the infant (postnatal week one) rats by an indirect dopamine agonist, and phencyclidine, an antagonist of the NMDA receptor.

Increasing the horizontal orientation of transition dipole moments in solution processed small molecular emitters.

The efficiency of organic light emitting diodes (OLEDs) can be improved by controlling the orientation of the transition dipole moment of the emitters. Currently, no effective methods exist for orienting the transition dipole moments in solution processed active layers for OLEDs. We investigate the orientation of the transition dipole moment of small molecular emitters in a host matrix of poly(9,9-dioctylfluorene) (PFO) by means of angle dependent luminescence intensity measurements.

Gram-Scale Syntheses and Conductivities of [10]Cycloparaphenylene and Its Tetraalkoxy Derivatives.

[10]Cycloparaphenylene ([10]CPP) and its tetraalkoxy derivatives were synthesized on the gram scale in 7 steps starting from 1,4-benzoquinone or 2,5-dialkoxy-1,4-benzoquinone. The key steps involve the highly cis-selective bis-addition of 4-bromo-4'-lithiobiphenyl to the quinones to produce a five-ring unit containing cyclohexa-1,4-diene-3,6-diol moiety, the platinum-mediated dimerization of the five-ring unit, and the HSnCl-mediated reductive aromatization of cyclohexadienediol. The tetraalkoxy substituents increased the solubility of [10]CPP in common organic solvents.

Analysis of Molecular Orientation in Organic Semiconducting Thin Films Using Static Dynamic Nuclear Polarization Enhanced Solid-State NMR Spectroscopy.

Molecular orientation in amorphous organic semiconducting thin-film devices is an important issue affecting device performance. However, to date it has not been possible to analyze the "distribution" of the orientations. Although solid-state NMR (ssNMR) spectroscopy can provide information on the "distribution" of molecular orientations, the technique is limited because of the small amount of sample in the device and the low sensitivity of ssNMR.

Genetic and molecular risk factors within the newly identified primate-specific exon of the SAP97/DLG1 gene in the 3q29 schizophrenia-associated locus.

The synapse-associated protein 97/discs, large homolog 1 of Drosophila (DLG1) gene encodes synaptic scaffold PDZ proteins interacting with ionotropic glutamate receptors including the N-methyl-D-aspartate type glutamate receptor (NMDAR) that is presumed to be hypoactive in brains of patients with schizophrenia. The DLG1 gene resides in the chromosomal position 3q29, the microdeletion of which confers a 40-fold increase in the risk for schizophrenia. In the present study, we performed genetic association analyses for DLG1 gene using a Japanese cohort with 1808 schizophrenia patients and 2170 controls.

Combined Inter- and Intramolecular Charge-Transfer Processes for Highly Efficient Fluorescent Organic Light-Emitting Diodes with Reduced Triplet Exciton Quenching.

Inter- and intramolecular charge-transfer processes are combined using an exciplex-forming host and a thermally activated delayed fluorescent dopant, for fabricating efficient fluorescent organic light-emitting diodes along with the reduced efficiency roll-off at high current densities. Extra conversion on the host from triplet exciplexes to singlet exciplexes followed by energy transfer to the dopant reduces population of triplet excitons on dopant molecules, thereby reducing the triplet exciton annihilations at high current densities.