Synthesis and mesomorphic properties of "side-on" hybrid liquid crystalline silsesquioxanes.

Novel hybrid silsesquioxane-based liquid crystalline derivatives with varied lengths of spacers and tails have been synthesized by hydrosilylation reactions of octakis(dimethylsiloxy)silsesquioxane and side-on mesogens via a platinum catalyst. The thermal behavior of three types of silsesquioxane-based liquid crystals (LCs), differentiated by the molecular structure of mesogens, was investigated by differential scanning calorimetry (DSC) and polarising optical microscopy (POM). Temperature-dependent small and wide-angle X-ray scattering was used to verify liquid crystalline phases, revealing that the silsesquioxane-based derivatives formed hexagonal columnar and nematic mesophases, and the effect of the molecular structure of the mesogens and the spacer length on the formation of LC phases is discussed. This investigation demonstrated that the choice of the "side-on" attachments plays a crucial role in enhancing the emergence of the nematic phase.

Electric-field-induced viscosity change of a nematic liquid crystal with gold nanoparticles.

The electro-rheological (ER) effect of a composite material consisting of a nematic liquid crystal (LC) and gold nanoparticles covered with mesogenic groups is discussed. The gold nanoparticles are covered by alkyl chains and liquid-crystalline compounds. The influences of the alkyl-chain length and the coverage by the alkyl chain and the mesogenic group on the miscibility of the nanoparticles with the LC are investigated by polarizing optical microscopy (POM). The presence of the gold nanoparticles in the nematic LC (5CB) leads to an enhanced ER response compared to that observed for 5CB. The prominent ER effect observed in this study is supported by the two mechanisms proposed, that is, the homogeneous and heterogeneous mechanisms. This study demonstrates the potential of a hybrid system consisting of an LC and gold nanoparticles to improve the ER effect.

Helicity Control of Circularly Polarized Luminescence from Aromatic Conjugated Copolymers and Their Mixture Using Reversibly Photoinvertible Chiral Liquid Crystals.

We synthesized cyclic chiral compounds [(R)/(S)-D2s] by linking a photoresponsive bisbenzothienylethene (BTE) moiety with an axially chiral binaphthyl moiety. Chiral nematic liquid crystals (N*-LCs) were prepared by adding chiral compounds as dopants to host N-LCs. These N*-LCs exhibited reversible chirality inversion upon photoisomerization between the open and closed forms of the BTE moiety. Here, the mechanism underlying chirality inversion in photoresponsive N*-LCs was investigated by comparing the helical twisting powers (HTPs) of (R)-D2s with those of analogous compounds. It was found that the helical inversion of N*-LCs containing (R)-D2s is governed by a delicate balance between two types of opposite helicity, i.e., the right-handed helicity of the inherently chiral binaphthyl moiety and the left-handed helicity of the BTE moiety bearing intramolecularly induced chirality. Namely, (R)-D2s induced chirality of the BTE moiety, which is attributed to intramolecular chirality transfer from the axially chiral binaphthyl moiety to the BTE moiety. Thus, (R)-D2s are chiral compounds with double chirality consisting of an intrinsically chiral moiety and an intramolecularly induced chiral moiety. Photocontrol of the helical senses and reversible photoinversion of the N*-LCs are achieved by utilizing UV and visible light irradiation and the steric effects of the substituents at the binaphthyl rings in (R)-D2s. In addition, photocontrol of the induced circularly polarized luminescence (CPL) was achieved using the photoinvertible N*-LC. The achiral aromatic conjugated copolymers that exhibited red, green, and blue fluorescence were dissolved and mixed in the present N*-LC, and they exhibited left- and right-handed white CPL with large dissymmetry factors (|glum|) ranging from 0.2 to 1.0. The CPLs were reversibly photoswitched due to photoisomerization between the open and PSS forms of the chiral compounds through UV and visible light irradiation.

Electrorheological effect and electro-optical properties of side-on liquid crystalline polysiloxane in a nematic solvent.

The electrorheological (ER) effect and the electro-optical properties of a ''side-on'' liquid crystalline polysiloxane (PS) are investigated. A large ER effect is observed and the response to the shear stress of neat PS in the nematic phase is shown to be affected by the shear rate. PS is also mixed with a low-molar nematic liquid crystal (5CB) in order to improve the response behavior to the applied electric field. The rheological properties of such mixtures are highly dependent on the concentration of 5CB. The composites respond faster to the applied electric field and have improved electro-optical properties. This study offers a new perspective on the development of liquid crystal materials for the ER effect.

Use of Maximum Tongue Pressure Values to Examine the Presence of Dysphagia after Extubation and Prevent Aspiration Pneumonia in Elderly Emergency Patients.

Background: Tongue pressure values in patients with dysphagia are reported to be significantly lower than those in healthy controls. The aim of this study was to measure the maximum tongue pressure (MTP) values after extubation in order to assess the presence of post-extubation dysphagia for the safe initiation of oral intake in elderly patients. Methods: Data from 90 patients who were extubated after mechanical ventilation under tracheal intubation were collected retrospectively. The patients were divided into two groups as follows: normal group (those who did not develop aspiration pneumonia after extubation; median age 62 years) and aspiration group (those who developed aspiration during the evaluation period; median age 75 years). The MTP values were measured at 6 h, 24 h, 3 days, and 7 days after extubation. Results: The values were significantly increased 24 h after extubation in the normal group (p < 0.05). Alternatively, no increase was observed even after 1 week of extubation in the aspiration group, and the values were significantly lower than those in the normal group. The cutoff values at 6 and 24 h after extubation, which were measured using the receiver operator characteristic (ROC) curve, were 17.8 and 23.2 kpa, respectively; furthermore, the results of these assessments were strongly related to the development of aspiration 6 h after extubation (χ2-value: 6.125; p = 0.0133). Conclusions: The presence of post-extubation dysphagia in patients who are intubated for ≥24 h can be predicted based on age and the MTP values at 6 h after extubation.

Preventive Effects of Sustainable and Developmental Perioperative Oral Management Using the "Oral Triage" System on Postoperative Pneumonia after Cancer Surgery.

Perioperative oral management is widely recognized in the healthcare system of Japan. Conventionally, the surgeon refers patients with oral problems to a dental or oral surgery clinic in the hospital. However, frequent in-house referrals were found to increase the number of incoming patients resulting in unsustainable situations due to an insufficient workforce. In 2011, the Center for Perioperative Medicine was established at our hospital to function as a management gateway for patients scheduled to undergo surgery under general anesthesia. The "oral triage" system, wherein a dental hygienist conducts an oral screening to select patients who need preoperative oral hygiene and functional management, was established in 2012. A total of 37,557 patients who underwent surgery at our hospital from April 2010 to March 2019 (two years before and seven years after introducing the system) were evaluated in this study. The sustainability and effectiveness of introducing the system were examined in 7715 cancer surgery patients. An oral management intervention rate of 20% and a significant decrease in the incidence of postoperative pneumonia (aOR = 0.50, p = 0.03) indicated that this system could be useful as a sustainable and developmental oral management strategy to manage surgical patients with minimal human resources.

Short-term effect of a smartphone application on the mental health of university students: A pilot study using a user-centered design self-monitoring application for mental health.

BACKGROUND: Despite the widespread recognition of the importance of mental health in young people, only a small proportion of young people with a mental disorder, including university students, receive mental health care. OBJECTIVE: We developed a smartphone application (Mental App) for the university students and examined the effects of the app on their mental health. METHODS: The app was designed according to a questionnaire survey conducted before this study. The Mental App was installed on the students' smartphone and the psychological tests (the Link Stigma Scale, the Center for Epidemiologic Studies Depression Scale, and the 12-item General Health Questionnaire) were performed on the same day. After using the App for two weeks, the students completed a questionnaire survey and underwent the same psychological tests. We compared the results between the app user and non-user group. RESULTS: A total of 68 students participated, of which 57 students completed the study (app user group, n = 28; control group, n = 29). The mean number of days spent using the app was 5.66 ± 3.16 (mean ± SD). The mean total screen time of the app was 9:03 ± 06:41(min:sec). The mean number of total actions (screen taps or swipes) was 161.91 ± 107.34. There were no significant between-group differences in the ΔLink Stigma Scale score (-0.11 ± 4.28 vs. -0.59 ± 3.30, p = 0.496) or the ΔCenter for Epidemiologic Studies Depression Scale score (-4.39 ± 7.13 vs. -2.07 ± 8.78, p = 0.143). There was a significant between-group difference in the ΔGeneral Health Questionnaire score (-2.21± 2.23 vs. -0.17 ± 2.69, p = 0.007). CONCLUSIONS: This non-randomized controlled pilot study indicates that the app we developed, may provide effective mental health care for university students, even in the short-term. Trial registration: UMIN000040332.

Micron-sized main-chain liquid crystalline elastomer actuators with ultralarge amplitude contractions.

Responsive surfaces composed of cylindrical or square micrometer-sized thermoresponsive pillars made of thiol-ene nematic main-chain liquid crystalline elastomers (LCEs) are produced by replica molding. The individual pillars behave as microactuators, showing ultralarge and reversible contractions of around 300-400% at the nematic to isotropic phase transition. The nematic main-chain LCE microactuators described here present contractions as large as the best macroscopic systems reported in the literature. Moreover, the contraction observed for this new system outperforms the best values already reported for other LCE microsystems.