Perovskite Nanosheet Hydrogels with Mechanochromic Structural Color.

Structural color colloidal sols of perovskite nanosheets were synthesized and were immobilized in a polymer hydrogel film by in situ photopolymerization, leading to a novel mechanochromic material. Visible absorption spectroscopy, polarized optical microscopy and small-angle X-ray scattering revealed that the nanosheets are aligned parallel to the film surface with the periodic distance of up to ca. 300 nm, giving the structural color tunable over full color range. The present structural color gel showed reversible mechanochromic response that detects weak stress of 1 kPa with the quick response time less than 1 ms as well as high mechanical toughness (compressive breaking stress of up to 3 MPa). These excellent properties are suitable for applications for mechano-sensors and displays.

High Virus Removal by Self-Organized Nanostructured 2D Liquid-Crystalline Smectic Membranes for Water Treatment.

To obtain high quality of drinking water free from biocontaminants is especially important issue. A new strategy employing smectic liquid-crystalline ionic membranes exhibiting 2D structures of layered nanochannels for water treatment is proposed for efficient virus removal and sufficient water flux. The smectic A (SmA) liquid-crystalline membranes obtained by in situ polymerization of an ionic mesogenic monomer are examined for removal of three distinct viruses with small size: Qß bacteriophage, MS2 bacteriophage, and Aichi virus. The semi-bilayer structure of the SmA significantly obstructs the virus penetration with an average log reduction value of 7.3 log10 or the equivalent of reducing 18 million viruses down to 1. Furthermore, the layered nanochannels of the SmA liquid crystal allow efficient water permeation compared to other types of liquid-crystalline membrane consisting of nanopores.

2D Photonic Colloidal Liquid Crystals Composed of Self-Assembled Rod-Shaped Particles.

Photonic crystals, characterized by their periodic structures, have been extensively studied for their ability to manipulate light. Typically, the development of 2D photonic crystals requires either sophisticated equipment or precise orientation of spherical nanoparticles. However, liquid-crystalline (LC) materials offer a promising alternative, facilitating the formation of periodic structures without the need for complex manipulation. Despite this advantage, the development of 2D photonic periodic structures using LC materials is limited to a few colloidal nanodisk liquid crystals. Herein, 2D photonic colloidal liquid crystals composed of biomineral-based nanorods and water is reported. The soft photonic materials with 2D structure by self-assembled LC colloidal nanorods are unique and a new class of photonic materials different from conventional solid 2D photonic materials. These colloids exhibit bright structural colors with high reflectance (>50%) and significant angular dependency. The structural colors are adjusted by controlling the concentration and size of the LC colloidal nanorods. Furthermore, mechanochromic hydrogel thin films with 2D photonic structure are developed. The hydrogels exhibit reversible mechanochromic properties with angular dependency, which can be used for an advanced stimuli responsible sensor.

Monodisperse nanosheet mesophases.

Self-assemblies of anisotropic colloidal particles into colloidal liquid crystals and well-defined superlattices are of great interest for hierarchical nanofabrications that are applicable for various functional materials. Inorganic nanosheets obtained by exfoliation of layered crystals have been highlighted as the intriguing colloidal units; however, the size polydispersity of the nanosheets has been preventing precise design of the assembled structures and their functions. Here, we demonstrate that the anionic titanate nanosheets with monodisperse size reversibly form very unusual superstructured mesophases through finely tunable weak attractive interactions between the nanosheets. Transmission electron microscopy, polarizing optical microscopy, small-angle x-ray scattering, and confocal laser scanning microscopy clarified the reversible formation of the mesophases (columnar nanofibers, columnar nematic liquid crystals, and columnar nanofiber bundles) as controlled by counter cations, nanosheet concentration, solvent, and temperature.

Nanostructure Control in Zinc Oxide Films and Microfibers through Bioinspired Synthesis of Liquid-Crystalline Zinc Hydroxide Carbonate; Formation of Free-Standing Materials in Centimeter-Level Lengths.

Free-standing zinc oxide in the forms of films and fibrous materials are expected to be used as functional devices such as piezoelectric devices and catalyst filters without being limited by the growth substrate. Herein, a synthetic morphology-control method for 2D and 1D free-standing ZnO materials with ordered and nanoporous structures by conversion of liquid-crystalline (LC) zinc hydroxide carbonate (ZHC) nanoplates is reported. As a new colloidal liquid crystal, the LC ZHC nanoplate precursors are obtained by a biomineralization-inspired method. The approach is to control the morphology and crystallographic orientation of ZHC crystals by using acidic macromolecules. Their nano-scale and oriented structures are examined. The LC oriented ZHC nanoplates have led to the synthesis of free-standing films and microfibers of ZHC in centimeter-level lengths, with the successful thermal conversion into free-standing films and microfibers of ZnO. The resultant ZnO films and ZnO microfibers have nanoporous structures and preferential crystallographic orientations that preserve the alignment of ZHC nanoplates before conversion.

Liquid Crystalline Colloidal Mixture of Nanosheets and Rods with Dynamically Variable Length.

Here, we demonstrate the novel double-component liquid crystalline colloids composed of mesogenic inorganic nanosheets and the rods with dynamically variable length controlled by temperature. As the length-controllable rod, stiff biopolymer microtubule is used, which was successfully polymerized/depolymerized from tubulin proteins through a biochemical process even in the presence of the nanosheets. The mesoscopic structure of the liquid crystal phase was reversibly modifiable as caused by the change of the rod length.

Development and validation of the Stimulant Relapse Risk Scale for drug abusers in Japan.

OBJECTIVE: To develop and validate a multidimensional measure of relapse risk for stimulants in Japanese drug abusers. METHODS: A Stimulant Relapse Risk Scale (SRRS) was developed based on the Marijuana Craving Questionnaire and a discussion among three psychiatrists. We created 48 items after confirming the items including a variety of relapse risk, such as craving (expectancy, compulsivity, etc.) and emotionality problems. One hundred inpatients and outpatients with a history of stimulant abuse (71 males and 29 females) were recruited with informed consent, and were administered the SRRS. The Visual Analogue Scale for drug craving (VAS), Addiction Severity Index for Japanese (ASI-J), and data on relapse within 3 and 6 months after the rating were used for the validation. RESULTS: Exploratory factor analysis highlighted five factors: anxiety and intention to use drug (AI), emotionality problems (EP), compulsivity for drug use (CD), positive expectancies and lack of control over drug (PL), and lack of negative expectancy for drug use (NE). These accounted for 48.3% of the total variance. Thirty of the 43 items were classified into the five subscales. Cronbach's alpha coefficient for each subscale ranged from .55 to .82, and was .86 for the total SRRS, indicating their adequate internal consistency. AI, CD, PL, and total SRRS were significantly correlated with the drug-use composite score of the ASI-J, supporting their concurrent validity. AI, PL, NE, and total SRRS were significantly correlated with relapse, implying their predictive validity. CONCLUSIONS: The SRRS has multidimensional psychometric properties useful for assessing the various aspects of stimulant relapse risk.

Reliability and validity of the Japanese version of the Addiction Severity Index (ASI-J).

The Addiction Severity Index (ASI) is a frequently used clinical and research instrument that collects data from substance abusers in seven problem areas: medical, employment, alcohol, drug use, legal, family-social functioning, and psychiatric status. In each area, the ASI provides a composite score and severity rating that estimate the seriousness of the problem and the client's need for treatment. In the present study, we investigated the reliability and validity of the Japanese version of the ASI (ASI-J). One hundred and eleven subjects with a history of drug abuse were interviewed with a test battery including the ASI with informed consent. This revealed that: (a) the problem areas were independent of each other, underscoring the need for multidimensional assessment, (b) the inter-rater correlation of severity ratings in each area ranged from 0.68 to 0.99, and Cronbach's alpha coefficient for the items used for the composite score in each area ranged from 0.57 to 0.86, indicating their reliability with the exception of the drug and employment areas, and (c) several composite scores were significantly correlated with the drug craving levels assessed by a visual analogue scale, the abstinence period, mental health, and/or relapse, supporting their concurrent and predictive validity. These results suggest that the ASI-J has acceptable reliability and validity.