Search

Recently, great advances have been made in the mechanochromic luminescence (MCL) of organic crystals that can switch their emission colors upon exposure to mechanical stimuli. Although several polymorphic crystals and solvates have exhibited multicolor MCL properties, a further deep understanding of the relationship between crystal structures and stimuli-responsive properties is required for rationally generating multicolor-emissive polymorphic crystals and solvates from a single luminescent compound. Herein, multicolor luminescence switching has been achieved for solvates of a phenanthroimidazolylbenzothiadiazole derivative with dianisyl groups. Four types of solvates with different luminescence properties changed their emission colors upon amorphization induced by mechanical stimuli. The amorphous state was recrystallized into solvates when exposed to solvent vapors. Furthermore, the solvate containing pyridine molecules showed a bathochromic shift in emission wavelength upon exposure to acid vapor. Typical acid-responsive luminescence switching is characterized by the protonation of the basic moiety of luminescent molecules, whereas in this study, the change in luminescence color could be induced by protonating non-luminescent pyridine molecules in the solvate. The present study potentially provides useful insights for the development of smart luminescent sensors.

Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy, the mechanism of which is involved in oxidative stress, can be lethal due to hemorrhage. Thus, we aimed to investigate the effect of hydrogen-rich water (HRW), in terms of oxidative stress, on intestinal mucosal damage as well as changes in the gut microbiome and the short-chain fatty acids (SCFAs) content in feces.Hydrogen-rich water was orally administered for 5 days to investigate the effectiveness of indomethacin-induced enteropathy in mice. Small intestinal damage and luminal reactive oxygen species (ROS) were evaluated to investigate the ameliorating effects of hydrogen. Then, components of the gut microbiome were analyzed; fecal microbiota transplantation (FMT) was performed using the cecal contents obtained from mice drinking HRW. The cecal contents were analyzed for the SCFAs content. Finally, cells from the macrophage cell line RAW264 were co-cultured with the supernatants of cecal contents.Hydrogen-rich water significantly ameliorated IND-induced enteropathy histologically and reduced the expression of IND-induced inflammatory cytokines. Microscopic evaluation revealed that luminal ROS was significantly reduced and that HRW did not change the gut microbiota; however, FMT from HRW-treated animals ameliorated IND-induced enteropathy. The SCFA content in the cecal contents of HRW-treated animals was significantly higher than that in control animals. The supernatant had significantly increased interleukin-10 expression in RAW264 cells in vitro.Hydrogen-rich water ameliorated NSAID-induced enteropathy, not only via direct antioxidant effects but also via anti-inflammatory effects by increasing luminal SCFAs. These results suggest that hydrogen may have therapeutic potential in small intestinal inflammatory diseases.

The functions of basophils have not been elucidated until recently because of their rarity. However, with recent developments in basophil-specific antibodies and basophil-deficient animals, the roles of basophils in various diseases related to chronic inflammation have been clarified. In this study, we aimed to investigate the roles of basophils in human ulcerative colitis (UC) and oxazolone (OXA) colitis using genetically engineered Mcpt8Immunohistochemical staining of human colon specimens was performed to examine the involvement of basophils in the pathogenesis of UC. We examined the correlation between the number of infiltrating basophils and the UC endoscopic index of severity (UCEIS), Mayo score, and Matts score. We also examined the correlation between eosinophil count and basophil infiltration. In murine experiments, we examined whether basophil infiltration was involved in OXA-induced colitis and whether basophil depletion improved inflammation in Mcpt8Colonic basophil infiltration was significantly increased in patients with UC. There were significant correlations between UCEIS, Mayo score, Matts score, and the number of infiltrating basophils. In murine OXA-induced colitis, a significant increase in basophil infiltration was observed. When basophils were depleted by diphtheria toxin in Mcpt8Basophil infiltration correlated with endoscopic, clinical, and pathological scores in human UC independently of eosinophil infiltration, and depletion of basophils ameliorated mucosal inflammation in murine OXA-induced colitis, collectively suggesting that basophils exert a proinflammatory role in chronic intestinal inflammation such as UC.

Though one of the primary functions of intestinal tuft cells us the sensing of the luminal content, the contribution of tuft cells to epithelial secretion has not been previously studied. We have found that in adult mice, induced tuft cell hyperplasia enhances the secretory responses to luminal short-chain fatty acids (SCFA) due to increased jejunal cholinergic signaling, whereas mast cell-mediated serotonergic signaling is predominant in the duodenum. Since mast cell density is higher in children with functional dyspepsia (FD) than in adults, we hypothesized that mast cell density and 5-HT signals may be increased by tuft cell hyperplasia more in adolescent (7-week-old; 7 wk) than in adult mice (15-week-old; 15 wk). Tuft cell hyperplasia was induced by oral sodium succinate (NaSuc, 100 mM) in the drinking water for 7 days in 7 wk or 15 wk mice, then assessed at 8 or 16 wk (8 w/16 w). Using Ussing chambers mounted with muscle-stripped mouse proximal duodenum or jejunum, the succinate receptor agonist cis-epoxy succinic acid (cESA, 1-30 mM) was applied to the mucosal bath whereas the selective free fatty acid receptor 2 (FFA2) agonist 4-CMTB (10 μM) was added to the serosal bath. Tuft cell doublecortin-like kinase 1 (DCLK1), mast cell protease 1 (MCPT1), and tryptophan hydroxylase 1 (TPH1/5-HT), used to measure tuft cell, mast cell, and enterochromaffin (EC) cell density, respectively, were assessed by real-time PCR and immunostaining.NaSuc treatment significantly increased the number of DCLK1-positive tuft cells and MCPT1-positive mast cells with no change in EC cell density in the duodenal and jejunal villi; density was higher at 8 w than at 16 w. mRNA expression of DCLK1 was increased in the duodenal and jejunal mucosa at both ages, whereas MCPT1, TPH1 and FFA2 were increased in both mucosæ at 8 w, but choline acetyltransferase (ChAT) was increased in the jejunal mucosa at 16 w. Luminal cESA increased atropine-inhibitable Isc in the jejunal mucosa, whereas 4-CMTB increased 5-HT3/5-HT4-mediated duodenal Isc. The Isc response to cESA in jejunum was enhanced at 16 w, whereas the response to 4-CMTB was enhanced at 8 w.These results suggest that NaSuc differentially enhances secretory responses, with jejunal serotonergic signals predominating at 8 w and cholinergic signals at 16 w. These data suggest that younger mice are more susceptible to tuft cell hyperplasia with resultant enhanced 5-HT signals with mast cell infiltration, consistent with clinical data. Supported by VA Merit Review This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Herein, we propose a new strategy to tune the magnitude of the mechanoresponsive shift of the maximum emission wavelength (Δλem). The Δλem of thienylbenzothiadiazole crystals has been extended to 69 nm by doping with a trace amount of dithienylbenzothiadiazole, whereas the pure crystal of thienylbenzothiadiazole exhibited a Δλem of 10 nm. This doping strategy should accelerate the development of advanced mechanosensing materials composed of organic crystals.

A chiral cation sensor comprising two pyrene rings and a diethylene glycol linker has been developed and utilized to detect Al3+ and Cu2+ ions based on differences in circular dichroism spectra. Remarkably, this sensor afforded the recognition of Al3+ and Cu2+ ions based on distinct differences in fluorescence spectra. The detection of Al3+ ions was achieved based on a typical excimer-to-monomer switching mechanism, whereas the oxidative dimerization of pyrenyl groups was proven to be the origin of the Cu2+-responsive switch in fluorescence spectrum. The Cu2+ cation-triggered formation of bipyrene structures, a process that has so far been overlooked in the development of pyrene-based sensors, holds promise for the generation of dual-responsive fluorescent sensors that afford the detection of two different analytes.

Organic emitters capable of changing their luminescence properties in response to mechanical stimuli have recently attracted considerable attention. While mechanoresponsive switching of luminescence color has been widely investigated, there are only a limited examples regarding the on-off luminescence intensity switching by mechanical stimulation. Consequently, rational design guidelines for mechanoresponsive switching of luminescence intensity have not been established. Herein, on-off luminescence switching has been achieved by two-component organic emitters composed of phenanthroimidazolylbenzothiadiazoles, which exhibit mechanochromic luminescence (MCL), and non-emissive pigments. In these two-component emitters, the emission color can be tuned by changing the MCL dye, and the apparent color under room light can be modulated by changing the non-emissive pigment. Moreover, we have demonstrated the encryption and decryption of luminescent displays by using the two-component emitter. The present two-component strategy is expected to serve as a useful method for developing advanced mechanoresponsive luminescent materials.

Takayasu arteritis (TA) sometimes presents with colitis, which may be diagnosed as inflammatory bowel disease unclassified (IBDU) because of atypical or mixed findings of ulcerative colitis (UC) and Crohn's disease. We herein report an 18-year-old girl presenting with colitis with an occasional high fever eventually diagnosed as TA with IBDU. Colonic inflammation was initially discontinuous and stronger in the proximal colon, atypical of UC. However, over 10-year observation, the distribution of colonic inflammation varied and became UC-like. Variations in TA-related colonic inflammations over time have been unclear. Our long-term observation might help clarify the details of TA-related colonic inflammation.

Polymorphic organic crystals that can switch their photophysical properties in response to mechanical stimuli are highlighted.

A σ-π extended aryldisilane, comprising a thienopyrazine group as an acceptor fragment and phenothiazine groups as the donor moiety, has been prepared through the introduction of two Si-Si bridges (compound 1). X-ray diffraction analysis determined the crystal structure of 1, and experimental and theoretical approaches investigated its optical properties. Solvatochromic studies revealed the dual emission of 1 in all solvents tested. Compound 1 also exhibited fluorescence in the solid state upon excitation with a hand-held UV lamp, as well as mechanochromic luminescent properties. The packing mode in the crystal structure, variation of phenothiazine conformation, morphological changes between crystalline and amorphous phases are the major factors showing reversible fluorescence under external stimuli. A theoretical conformer study found that 1 exists in distinct conformational groups differing in Gibbs free energy by less than 3 kcal mol-1 . The conformer in the crystalline state of 1 can promote the complete separation of the HOMO and LUMO between the phenothiazine donor and the thienopyrazine acceptor, linked by the disilane linker. HOMO-LUMO energy transition in the crystalline state is forbidden due to the lack of frontier orbital overlap. Crystalline state emission showed LUMO → HOMO-1 transition (locally excited (LE) state). In the amorphous state, the partial presence of quasi-axial conformers allows intramolecular charge-transfer type emission via energy transfer from dominant quasi-equatorial conformers. The strategy proposed in this work provides important guidance for developing stimuli-responsive materials with controlled excited states.

BACKGROUND AND AIM The artificial sweetener acesulfame potassium (ACK) is officially approved as safe for intake and has been used in processed foods. However, ACKs have been reported to induce metabolic syndrome, along with alteration of the gut microbiota in mice. In recent years, studies have suggested that this artificial sweetener promotes myeloperoxidase reactivity in Crohn's disease-like ileitis. We aimed to investigate the effect of ACK on the intestinal mucosa and gut microbiota of normal mice. METHODS Acesulfame potassium was administered to C57BL/6J mice (8 weeks old) via free drinking. Intestinal damage was evaluated histologically, and messenger RNA (mRNA) levels of TNF-α, IFN-γ, IL1-β, MAdCAM-1, GLP1R, and GLP2R were determined with quantitative reverse transcription polymerase chain reaction (qRT-PCR). Immunohistochemistry was performed to examine the expression of MAdCAM-1 in the small intestine. The composition of gut microbiota was assessed using high-throughput sequencing. We performed intravital microscopic observation to examine if ACK altered lymphocyte migration to the intestinal microvessels. RESULTS Acesulfame potassium increased the expression of proinflammatory cytokines, decreased the expression of GLP-1R and GLP-2R, and induced small intestinal injury with an increase in intestinal permeability, and ACK treatment induced microbial changes, but the transfer of feces alone from ACK mice did not reproduce intestinal damage in recipient mice. ACK treatment significantly increased the migration of lymphocytes to intestinal microvessels. CONCLUSION Acesulfame potassium induces dysbiosis and intestinal injury with enhanced lymphocyte migration to intestinal mucosa. Massive use of non-caloric artificial sweeteners may not be as safe as we think.

Despite the recent increased interest in organic small molecule luminophores that exhibit circularly polarized luminescence (CPL) or mechanochromic luminescence (MCL), MCL behavior in chiral luminophores that display solid-state CPL still remains elusive. Herein, it is reported that a chiral diamine-linked bispyrene derivative exhibits a rare MCL behavior in response to two different types of mechanical stimuli, namely utrasonication and grinding. Moreover, an unprecedented switching of solid-state CPL has been achieved for the chiral bispyrene between two states that can respond to the different mechanical stimuli. These findings should help to advance the development of practical CPL materials.

When intense lightwaves accelerate electrons through a solid, the emerging high-order harmonic (HH) radiation offers key insights into the material1,2,3,4,5,6,7,8,9,10,11. Sub-optical-cycle dynamics—such as dynamical Bloch oscillations2,3,4,5, quasiparticle collisions6,12, valley pseudospin switching13 and heating of Dirac gases10—leave fingerprints in the HH spectra of conventional solids. Topologically non-trivial matter14,15 with invariants that are robust against imperfections has been predicted to support unconventional HH generation16,17,18,19,20. Here we experimentally demonstrate HH generation in a three-dimensional topological insulator—bismuth telluride. The frequency of the terahertz driving field sharply discriminates between HH generation from the bulk and from the topological surface, where the unique combination of long scattering times owing to spin–momentum locking17 and the quasi-relativistic dispersion enables unusually efficient HH generation. Intriguingly, all observed orders can be continuously shifted to arbitrary non-integer multiples of the driving frequency by varying the carrier-envelope phase of the driving field—in line with quantum theory. The anomalous Berry curvature warranted by the non-trivial topology enforces meandering ballistic trajectories of the Dirac fermions, causing a hallmark polarization pattern of the HH emission. Our study provides a platform to explore topology and relativistic quantum physics in strong-field control, and could lead to non-dissipative topological electronics at infrared frequencies.

A series of σ-π extended octamethyltetrasilanes, which have phenothiazine, 9,9-dimethyl-9,10-dihydroacridine, or phenoxazine (

Background The small intestine plays a central role in gut immunity, and enhanced lymphocyte migration is involved in the pathophysiology of various enteropathy. Bile acid (BA) is closely related to lipid metabolism and gut microbiota, and essential for gut homeostasis. However, the effects of BA on gut immunity have not been studied in detail, especially on the small intestine and lymphocyte migration. Therefore, we aimed to investigate the effect of BA on small intestinal lymphocyte microcirculation. Methods The effect of deoxycholic acid (DCA), taurocholic acid (tCA) or cholic acid (CA) on the indomethacin (IND)-induced small intestinal enteropathy in mice was investigated. Lymphocyte movements were evaluated after exposure to BA using intravital microscopy. The effects of BA on surface expression of adhesion molecules on the vascular endothelium and lymphocytes through BA receptors were examined in vitro. Results IND-induced small intestinal enteropathy was histologically aggravated by DCA treatment alone. The expression of adhesion molecules ICAM-1 and VCAM-1 were significantly enhanced by DCA. Exposure to DCA increased lymphocyte adhesion in the microvessels of the ileum, which was partially blocked by anti-α4β1 integrin antibody in vivo. The expression of ICAM-1 and VCAM-1 were significantly enhanced by DCA in vitro, which was partially suppressed by the sphingosine-1-phosphate receptor 2 (S1PR2) antagonist. The S1PR2 antagonist significantly ameliorated IND-induced and DCA-exaggerated small intestinal injury. Conclusion DCA exacerbated IND-induced small intestinal enteropathy. DCA directly acts on the vascular endothelium and enhances the expression levels of adhesion molecules partially via S1PR2 leading to enhanced small intestinal lymphocyte migration.

Mechanochromic luminescence (MCL) refers to a reversible color change of the solid-state emission induced by mechanical stimulus such as grinding, shearing, and compressing. A growing number of MCL...

OBJECTIVES/HYPOTHESIS Transoral surgery (TOS) has become increasingly popular for patients with superficial hypopharyngeal squamous cell carcinoma (SCC). However, the number of patients in whom metachronous multiple SCC of the head and neck (HNSCC) occurs has also increased. In this study, we investigated whether multiple lugol-voiding lesions (LVLs) in the pharyngeal background mucosa observed during TOS would be a biomarker of metachronous HNSCC. STUDY DESIGN Retrospective study. METHODS We examined 362 patients who underwent TOS for superficial hypopharyngeal carcinoma. Endoscopic images were reviewed in a blinded fashion by two endoscopists. LVLs in the pharyngeal mucosa were graded as follows: A, no lesions; B, 1 to 4 lesions; and C, ≥5 lesions per endoscopic view. RESULTS Cumulative incidence curves of secondary HNSCC in the groups of grades A, B, and C revealed 3-year incidence rates of 14.4%, 18.8%, and 29.3%, respectively (P = .001 for A vs. C and P = .002 for B vs. C). Cumulative incidence curves of third HNSCC in the groups of grades A, B. and C revealed 5-year incidence rates of 3.9%, 9.8%, and 19.6%, respectively (P = .001 for A vs. C and P = .006 for B vs. C). Cumulative incidence curves of fourth HNSCC in the groups of grades A, B, and C revealed 7-year incidence rates of 0%, 2.3%, and 13.2%, respectively (P = .025 for A vs. C and P = .009 for B vs. C). CONCLUSIONS Multiple LVLs in the pharyngeal mucosa increase the risk of development of metachronous multiple HNSCC. LEVEL OF EVIDENCE 3 (nonrandomized, controlled cohort/follow-up study) Laryngoscope, 131:2036-2040, 2021.

The reversible color change of the solid-state emission upon exposure to mechanical stimuli is called mechanochromic luminescence (MCL). In spite of the recent growing interest in MCL materials, only a limited number of organic crystalline materials exhibit two-step MCL that responds to the mechanical stimuli of different intensities. Herein, we report two types of two-step MCL as well as bicolor MCL of phenanthroimidazolylbenzothiadiazole derivatives that bear a substituted phenyl group on the nitrogen atom of the phenanthroimidazole ring. One-way type two-step MCL was observed for a p-bromo-substituted derivative, whereas an o-bromo-substituted derivative displayed a rare back-and-forth type two-step MCL. The other derivatives including the m-bromo-substituted compound showed typical bicolor MCL. Specifically, three types of MCL behaviors are exhibited by changing the position of the bromo group. Single-crystal X-ray diffraction analyses revealed that the crystal system is altered by introducing different substituents. The mode of intermolecular interactions differs depending on the crystal system, which should account for the difference in emission wavelength and MCL properties of the crystalline samples. Based on powder X-ray diffraction and differential scanning calorimetry measurements, one-way type MCL can be rationalized in terms of the crystal-to-crystal transitions followed by crystal-to-amorphous transitions. The mechanism of the back-and-forth type MCL is proposed as the destruction of extended intermolecular interactions upon crushing the crystals followed by amorphization upon strong grinding. These results provide useful insights into the future development of multi-step MCL systems with potential applications in advanced mechano-sensing technologies.

Soft crystals are a class of smart materials that can switch their photophysical or mechanical properties in response to gentle external stimuli. A representative stimuli-responsive behavior of soft crystals is mechanochromic luminescence (MCL), i.e., a reversible color change of solid-state photoluminescence induced by external mechanical stimuli. Together with the rapid growth in the area of solid-state photoluminescence including fluorescence, room-temperature phosphorescence (RTP), thermally activated delayed fluorescence (TADF), white-light emission (WLE), and circularly polarized luminescence (CPL), a number of soft crystals that exhibit MCL behaviors have been reported during the past decade. In the typical MCL of soft crystals, the emission color switches in the bathochromic direction upon amorphization by grinding and recovers to the original color upon recrystallization by heating or exposure to organic solvents. Relatively few are known to exhibit hypsochromically shifted MCL, two-step MCL, self-recovering MCL, or mechanical-stimuli-induced single-crystal-to-single-crystal (SCSC) transitions. Rational design guidelines to control the mechanoresponsive properties of soft crystals have not yet been established. This review summarizes the systematic studies on the substituent effect to control the MCL properties of soft crystals. Recent studies provide useful insights into the effects of electronic and steric differences of substituents on crystal structure, luminescence properties, and mechanoresponsive behaviors.

The relationship between the magnetic interaction and photoinduced dynamics in antiferromagnetic perovskites is investigated in this study. In La${}_{1/3}$Sr${}_{2/3}$FeO${}_{3}$ thin films, commensurate spin ordering is accompanied by charge disproportionation, whereas SrFeO${}_{3}$ thin films show incommensurate helical antiferromagnetic spin ordering due to increased ferromagnetic coupling compared to La${}_{1/3}$Sr${}_{2/3}$FeO${}_{3}$. To understand the photoinduced spin dynamics in these materials, we investigate the spin ordering through time-resolved resonant soft X-ray scattering. In La${}_{1/3}$Sr${}_{2/3}$FeO${}_{3}$, ultrafast quenching of the magnetic ordering within 130 fs through a nonthermal process is observed, triggered by charge transfer between the Fe atoms. We compare this to the photoinduced dynamics of the helical magnetic ordering of SrFeO${}_{3}$. We find that the change in the magnetic coupling through optically induced charge transfer can offer an even more efficient channel for spin-order manipulation., 7 pages, 5 figures

Despite recent great advances in the area of mechanochromic luminescence (MCL), the control over the direction for the mechanical-stimuli-induced shift of the emission maximum still remains a chall...

We investigate the ultrafast lattice dynamics in ${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$ via time-resolved x-ray diffraction measurements using an x-ray free-electron laser at SPring-8 Angstrom Compact free-electron LAser (SACLA). The profile of the Bragg peaks substantially changes after strong photoexcitation, where the $c$ axis length of the lattice initially contracts, followed by expansion. These ultrafast lattice contractions and expansions significantly depend on the pump fluence, and it is suggested that a strong normal stress is applied along the $c$ axis. To obtain a phenomenological understanding of the observed lattice dynamics, we performed calculations based on a two-temperature model and an ultrafast thermoelasticity model. Our results showed that a steep gradient of the electron temperature induced by photoexcitation generates a blast force, which acts as a strong normal stress. We propose that a temporal stress can be applied by a strong optical pump, and this scheme can be another route for the application of uniaxial stress to superconductors.

The development of in situ analysis techniques for visualizing and linking macro- and nanoscopic features of external stimulus-responsive materials is crucial for their rational design and applications. Herein, we investigate the mechanical stress-induced emission changes in electron donor-acceptor type organic dye molecules in solid states through in situ single-particle fluorescence spectroscopy combined with macroscopic and nanoscopic stimulation systems. The change in emission color from green to yellow was attributed to repeated rubbing or scratching of the crystal surface, and not to simple cutting. This change was due to partial amorphization, which changed the intra- and intermolecular charge-transfer interactions of stacked molecules near the surface. We believe that this study will facilitate the efficient design of mechano-responsive materials with finely controlled and responsive properties.