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Abstract New carbazole-modified pyrazole derivatives were synthesized. It was found that tert -butylcarbazole derivatives of TCPDP , TCPHP , TCPPM and TCPPF exhibited reversible mechanofluorochromic (MFC) behavior under the treatment of grinding/fuming with CH 2 Cl 2. Particularly, the emission of the as-synthesized crystals of TCPDP was weak and emerged in the ultraviolet region, while the grinding led to significant red-shift of the emission to the visible-light region, accompanied with the significant fluorescence enhancement on account of the formation of J -aggregates. Thus, TCPDP showed intriguing fluorescence switching in visible-light region during MFC processes, which could be easily observed visually. Additionally, TCPDP , TCPHP , TCPPM and TCPPF could form stable organogels in some organic solvents. Notably, the solutions of TCPPM and TCPPF were almost non-emissive, but gelation-induced blue emission was achieved. Thus, the fluorescence could be also turned on due to the AIE (aggregation-induced emission) during the gel formation. Graphical abstract Image 1 Highlights • New carbazole-modified pyrazole derivatives were synthesized. • Tert -butylcarbazole derivatives showed reversible mechanofluorochromism and good gelation abilities. • High-contrast mechanofluorochromism of TCPDP was achieved via fluorescence switching in visible-light region. • Gelation-induced emission of TCPPM and TCPPF was detected. [ABSTRACT FROM AUTHOR]

Abstract New tert -butylcarbazole modified β-diketone difluoroboron complexes CVB , PCVB , MPCVB and BPCVB have been synthesized. It was found that BPCVB without any traditional gelation group formed organogel in toluene, xylene, 1,3,5-triethylbenzene and 1,4-dioxane. The gained organogel and xerogel based on BPCVB gave a strong red fluorescence. The emission for the xerogel-based film was quenched by aniline vapor selectively, and the detection limit was as low as 2.0 ppb. It is interesting that the solid emission of the synthesized complexes was in the range of 600–850 nm, and the highest solid fluorescent quantum yield reached 0.37. These NIR dyes showed MFC behavior. For example, the as-synthesized sample of PCVB gave an emission band at 647 nm, and emitted red light under UV irradiation. The grinding of the as-synthesized sample resulted in the emitting color to turn to dark purple, accompanied with the red-shift of the emission to ca. 700 nm. The emission could recover to initial states by fuming the ground powders with CH 2 Cl 2 vapor. Based on the UV–vis spectra and XRD patterns in different solid-state for PCVB suggested that π-aggregates were formed in the as-synthesized crystals, and the grinding could destroy the aggregates and yield amorphous state. The transformation between crystalline and amorphous states led to MFC behavior. Graphical abstract Image 1 Highlights • New β-diketone difluoroboron complexes with high solid fluorescence quantum yields were synthesized. • BPCVB without any traditional gelation group formed organogels. • The xerogel-based film of BPCVB with red emission could detect gaseous aniline selectively. • These NIR dyes showed MFC behavior. [ABSTRACT FROM AUTHOR]

New difluoroboron β-carbonyl cyclic ketonate complexes CnB (n = 2, 16), in which carbazole was linked to difluoroboron β-diketonate directly, and DCnB (n = 2, 16), where two terminal carbazole units were bridged by vinyl groups to link to difluoroboron β-diketonate core, were synthesized. They exhibited reversible mechanofluorochromic (MFC) behavior under grinding/fuming or heating treatment. Particularly, the emission of DC2B and DC16B emerged in the range of 650–850 nm in the solid-state. They gave red and rose-red luminescence in the as-synthesized crystals and in the ground powders, respectively, during MFC processes. Such MFC materials emitting NIR (near-infrared) light were seldom reported. In addition, compared with C2B , C16B showed high-contrast mechanofluorochromism because the long alkyl chain might decrease the strength of π-π interactions in the as-synthesized crystals, leading to the emission appeared at the high-energy region (483 nm). The disassembling of parts of π-aggregates and the improvement of the molecular planarity led to red-shift of the emission (509 nm) upon grinding. [ABSTRACT FROM AUTHOR]

Herein, three new fluorostyrylindazoles bearing one, three and five fluorine atoms (FPIZ , TFPIZ and PFPIZ) have been synthesized. Interestingly, the crystal of PFPIZ bent back away from the lighht source at the initial stage of 365 nm light irradiation, and then it showed phototropic bending when prolong the irradiation time without changing the irradiation direction. It was found that the photo-induced [2 + 2] cycloaddition could lead to the expansion and contraction of the unit cell in different directions, and in turn trigger the crystal to exhibit macroscopic mechanical moving. Meanwhile, the photochemical reaction was reasonable for the photochromism of the PFPIZ , which is helpful for the visual observation of the photomechanical effects. For instance, the fluorescence of the crystals of PFPIZ was changed from blue-purple to white under 365 nm irradiation. Besides, TFA (trifluoroacetic acid) could quench the emission of the synthesized fluorostyrylindazoles to different degree in solutions as well as in the films. The acidochromism of the styrylindazole derivatives was originated from the protonation of indazole by acid. The design of multi-stimuli response crystalline materials would be helpful for the fabrication of intelligent photoactuators and fluorescence sensors. [Display omitted] • The molecular crystals based on (E)-1-methyl-3-(2-(perfluorophenyl)vinyl)-1 H -indazole exhibited photomechanical effects. • Stereospecific photo-induced [2 + 2] cycloaddition underwent in the crystal of PFPIZ. • The fluorescence of the crystals of PFPIZ was changed from blue-purple to white on account of the photodimerization. • The films of fluorostyrylindazoles could probe gaseous trifluoroacetic acid rapidly and sensitively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Five strains of LAB were associated with improved flavor. • LAB fermentation was associated with increased organic acid and decreased sugars. • Important metabolic compounds of different LAB fermentation were identified. • Specific strains can improve enzyme inhibition and antioxidant activities. • Isoquercitrin and m -coumaric acid content reflected the strain/species specificity. Lactic acid bacteria (LAB) have exhibited strain/species specificity for different food matrices. We investigated the impact of LAB fermentation on the flavor, chemical profile, and bioactivity of goji juice. The colony counts of five selected strains reached above 8.5 log CFU/mL. The fermentation increased the organic acids, decreased the sugars, and improved the sensory quality of goji juice. The majority of the strains had increased acetic acid, heptanoic acid, ethyl phenylacetate, and linalool levels. Specific strains suppressed α-glucosidase and pancreatic lipase activities and increased the antioxidant activities of fermented goji juice. Based on non-targeted metabolomics and activities, 23 important differential metabolites were screened among 453 metabolites. The quantification results showed that isoquercitrin and m -coumaric content varied among strains, reflecting the strain specificity in flavone and flavonol biosynthesis and phenylalanine, tyrosine, and tryptophan biosynthesis. These findings will provide useful information for fermented goji juice biochemistry research. [ABSTRACT FROM AUTHOR]

Four fluorescent low molecular weight gelators based on benzoxazole or benzothiazole functionalized pyrimidine were designed and synthesized. The ability of the target was tested, and all compounds could form stable supramolecular gels in an alcohol/water mixture and its fluorescence increased during gel formation. Photophysical spectra during gel formation, SEM, XRD, FT-IR study suggested that the self-assembly was driven by hydrogen bonding, van der Waals forces and weak π-π interaction. Interestingly, the gel collapsed after being illuminated by 365 nm UV light and 1H NMR of the gel before and after illumination proved that the [2 + 2]-cycloaddition between the double bond of pyrimidine was responsible for the light response. Furthermore, the fluorescent of xerogel film could be quenched by volatile acids while the fluorescent of the solution was enhanced after acid was added. The different phenomena were discussed. The nano-fiber assembled via gel formation could be used as fluorescent imaging material of latent fingerprints. [Display omitted] • Design and synthesis of novel uracil derivatives containing benzoxazole and benzothiazole. • Benzoxazole-modified uracil derivatives exhibit good gelation abilities and driving force of gel formation was investigated. • The gel could respond to light and acid. The response mechanism was studied. • The nano-materials assembled via gel formation could be used as fluorescent imaging material of latent fingerprints. [ABSTRACT FROM AUTHOR]

Three push-pull chromophores comprising a triphenylamine (TPA) as electron-donating moiety and functionalized β-diketones as electron acceptor units are studied by various spectroscopic techniques. The time-correlated single-photon counting data shows that increasing the number of electron acceptor units accelerates photoluminescence relaxation rate of compounds. Transient spectra data shows that intramolecular charge transfer (ICT) takes place from TPA units to β-diketones units after photo-excitation. Increasing the number of electron acceptor units would prolong the generation process of ICT state, and accelerate the excited molecule reorganization process and the relaxation process of ICT state. [ABSTRACT FROM AUTHOR]

New D-π-A type aminostyrylquinoxaline derivatives ( QDMA1 , QDMA2 , QTPA1 and QTPA2 ) were synthesized via Knoevenagel condensation reactions. It was found that their ICT (intramolecular charge transfer) emission were red-shifted significantly with increasing the solvent polarities. Interestingly, compound QTPA2 bearing two terminal triphenylamine groups exhibited reversible mechanofluorochromism. The emission of the as-synthesized crystals of QTPA2 was located at 542 nm, and it was red-shifted to 592 nm upon grinding, so the emitting color was changed from yellow to carmine. Meanwhile, the emission could be recovered when the ground powders were fumed with DCM vapor. XRD patterns and DSC curves in different solid states demonstrated that the mechanofluorochromism was due to the transformation between the crystalline and amorphous states. In addition, the protonation of the synthesized aminostyrylquinoxalines by TFA could lead to the colors of the solutions to change into dark green from yellow, accompanied with the quenching of the emission. Furthermore, we also found that the emission of QTPA2 in the film could be quenched significantly and rapidly stimulated by TFA vapor, and the detection limit and the decay time were estimated to be 167 ppb and 0.47 s, respectively. Therefore, the aminostyrylquinoxaline derivatives could be used as sensory materials to detect acids in solutions and in the films by naked eyes. [ABSTRACT FROM AUTHOR]

Efficacious and convenient removal of organic dye contaminants from wastewater is a challenge for public health and ecosystem protection. Here we fabricate a novel type of Fe 3 O 4 @MOFs (Metal-organic frameworks) magnetic porous composite materials. ZIF-67 (Zeolitic imidazolate framework-67) nano-crystals as an attractive subfamily of MOF was selected to fabricate Fe 3 O 4 -PSS@ZIF-67 composites (defined as MZIF-67). MZIF-67 composites are core-shell structure, for which the aggregation core of Fe 3 O 4 nanoparticles is coated with petal-like ZIF-67 crystals, in which Co 2+ firstly combines with SO 3 2− provided by PSS (poly (styrenesulfonate, sodium salt)) to form nucleation. MZIF-67 composites perform well on methyl orange (MO) adsorption, which could be attributed to the highly porosity and the nature of Lewis base of coordinated Co 2+ centrals. The results show that the equilibrium adsorption capacity for MO is up to 738 mg·g −1 (when pH = 8.0, contact time is 7 h, adsorbent dose is 5 mg and initial MO concentration is 400 mg·L −1 ). In addition, MZIF-67 composites could selectively separate MO from the mixture solution of MO and MB (methylene blue). The removal rate of MO is up to 92%. The concentration ratio of MO/MB is 0.04. And the separation efficiency is up to 96%. The results suggest MZIF-67 composites could be a good candidate for treatment of dye-bearing wastewater. [ABSTRACT FROM AUTHOR]

New difluoroboron β-ketoiminate boron complexes bearing benzoxazole ( CBO ) and benzothiazole ( CBS ) have been synthesized. It was found that CBO was almost non-emissive in THF, and the emission could be intensified significantly when great amount of H 2 O was added, illustrating AIE (aggregation-induced emission) property. CBS could not show AIE property in THF/H 2 O system, but its emission in solid state was also strong. The single crystal structure of CBS suggested that π-π interactions and the hydrogen bonds of C(Ar)−F⋅⋅⋅H, C(Ar)−H⋅⋅⋅S and C(Ar)−H⋅⋅⋅Cl would suppress the rotation of single bonds, resulting into obvious emission enhancement. It is interesting that the as-synthesized crystals of CBO and CBS both emitted azure light, and the grinding made their emitting colors to change into cyan and green, which could be recovered under fuming with DCM or heating. The reversible mechanofluorochromism was due to the transformation between crystalline and amorphous states, which could be confirmed from the results of absorption spectra, XRD patterns and DSC curves in different solid states. Additionally, the high-contrast mechanofluorochromism of CBS compared with CBO might be originated from the loose packing in crystalline state and the better π-electron delocalization. [ABSTRACT FROM AUTHOR]

New β-diketone-boron difluoride complexes functionalized with tetraphenylethene ( TPEB , DTPEB and TTPEB ) which exhibit AIE (aggregation-induced emission) properties have been synthesized. It was found that only boomerang-shaped DTPEB without any traditional gelation groups could form organogel in specific organic solvents. It gave strong orange red fluorescence in organogel as well as in xerogel-based film although it was non-emissive in solution. It is interesting that the emission of DTPEB in xerogel-based film could be quenched significantly upon exposure to triethylamine (TEA) vapour, and the detection limit was as low as ca. 0.1 ppb. This work provides a strategy for the synthesis of a new rigid non-traditional π-gelator via the construction of a boomerang-shaped π-conjugated skeleton. In addition, the gelation of the π-gelators with AIE ability is a facile method for the fabrication of luminescent organic nanomaterials. [ABSTRACT FROM AUTHOR]

Two push-pull compounds, which are comprised of triphenylamine (TPA) (electron donor units) and functionalized β-diketones difluorboron complexes (electron acceptor units) are probed by many spectroscopies, which offers the relationship between electron acceptor and the intrinsic excited state properties of push–pull chromophores. We found that the photoluminescence (PL) intensity would enhance with the number of electron acceptor. Transient absorption (TA) data shows that intramolecular charge transfer (ICT) process really exists in the two molecules after photoexcitation and this process would be prolonged through increasing the electron-acceptor, which would be responsible for the improvement of PL property. [ABSTRACT FROM AUTHOR]

• RAN promoted the polarization of macrophages towards M1 by activating the PI3K/Akt2/NF-κB signaling pathway. • p-Akt2 can enhance the endocytosis of macrophages by regulating GSK3β/Dynamin1 pathway. • RAN as adjuvant could effectively increase the differentiation of Th1 cells after M1 polarization. • RAN could enhance the killing function of CTL to inhibit tumor growth and improve survival rate as adjuvant tumor vaccine. Adjuvants are an indispensable component of vaccines, but there are few adjuvants for human vaccines. H2 receptor blockers, inhibiting gastric acid secretion, have immune enhancement effects. Ranitidine (RAN) is a water-soluble H2 receptor blocker, and whether it has an immune-enhancing effect is still unknown. In this study, flow cytometry, western blotting, and immunofluorescence methods were used to analyze whether RAN could activate macrophage polarization to the M1 phenotype in vivo and in vitro. Here, we found that the M1 inflammatory cytokine levels and surface markers in RAW264.7 cells were upregulated by NF-κB activation, possibly through the PI3K-Akt2 signaling pathway, after RAN treatment. Endocytic function was also enhanced by feedback regulation of Akt2/GSK3β/Dynmin1 signaling. Furthermore, to evaluate the adjuvant function of RAN, we used OVA plus RAN as a vaccine to inhibit the growth of B16-OVA tumors in mice. We also found that in the RAN adjuvant group, macrophage polarization to M1, Th1 cell differentiation, and cytotoxic T lymphocyte (CTL) activation were significantly upregulated. The tumor growth of mice was inhibited, and the survival rate of mice was significantly improved. This study provides new evidence for the mechanism by which RAN activates the immune response and is expected to provide a new strategy for the research and development of tumor vaccine adjuvants. [ABSTRACT FROM AUTHOR]

[Display omitted] • An all-in-one MoS 2 -based electrocatalyst for hydrogen evolution is constructed by inkjet printing. • Inkjet-printed 3D architecture contributes to the exposure of active catalytic sites. • 1T-MoS 2 surrounded by graphene reduces the charge-transfer impendence. • Cu contact supports the efficient electron injection from the electrode to catalytic materials. • The facile and scalable avenue allows the fabrication of electrocatalysts with high throughput. 2D transition metal dichalcogenides (TMDs) are emerging as promising alternative electrocatalysts for hydrogen evolution reaction (HER). However, key challenges are the limited density of available activity sites and poor electron accessibility. Herein, Cu film supported MoS 2 -based electrocatalyst with partial 1T phase and 3D architecture is constructed by inkjet printing. We aim to investigate if this configuration could provide largely exposed edge sites and enhance electron transfer for ultra-efficient hydrogen production. Towards this end, an ink containing few-layer MoS 2 nanosheets and reduced graphene oxide (RGO) is firstly prepared by liquid-phase exfoliation, in which semiconducting 2H-MoS 2 is partially transformed to metallic 1 T-MoS 2. We demonstrate that 1) nanosized few-layer MoS 2 spatially patterned by inkjet-printing provides sufficient active site exposure, 2) the 1T-MoS 2 and RGO conductive network reduce the charge-transfer impedance, and 3) the Cu support enhances the catalyst-electrode charge injection. Our all-in-one structure exhibits outstanding HER activities with low overpotential (51 mV at 10 mA cm−2 and 126 mV at 100 mA cm−2) and very low Tafel slope (32 mV dec-1). Also, the as-engineered electrode demonstrates ultrahigh cathodic current density. This work provides a facile, inexpensive, and scalable way for designing and fabricating TMDs-based electrocatalysts with excellent HER activity. [ABSTRACT FROM AUTHOR]

New tert -butylcarbazole-based Schiff bases TPMP and TPMA , as well as the difluoroboron complex of salicylaldimine TPOB were synthesized. It was found that TPMP and TPMA without any traditional gelation group could form organogels in toluene and o -dichlorobenzene, etc., stimulated by ultrasound. It was suggested that the planar π-skeletons and the large steric effect of tert -butyl groups would lead to appropriate π-π interaction to induce the gel formation. Interestingly, the nanofibers formed from salicylaldimine derivative TPMP could emit strong yellowish green light under UV irradiation. It should be noted that the difluoroboron complex of TPOB with non-planar aromatic unit could not gelate the selected solvents on account of the weak π-π interaction. However, it showed reversible piezofluorochromism. The as-prepared crystal of TPOB emitted strong yellow light and could be transformed into the powders emitting orange red light after grinding, and the fluorescence could recover when the ground powders were heated. Such reversible changes of the emitting colors for TPOB by the treatment of grinding and heating was resulted from the transformation between crystalline and amorphous states. Herein, we provided the strategy for fabricating new nontraditional π-gels directed by appropriate π-π interaction and new piezofluorochromic dyes via the introduction of non-planar π-skeletons. [ABSTRACT FROM AUTHOR]

• BAI treatment delayed the onset of EAE, alleviate clinical symptoms, demyelination and inflammatory cell infiltration. • BAI inhibited the overactivation of M1 microglia/macrophages in vivo and in vitro, significantly decreased the expression of proinflammatory cytokines in M1 microglia/macrophages. • BAI has the binding ability to the SH2 domain of STAT1, and leaved P-STAT1 in the cytoplasm rather than transferred to the nucleus during inflammatory stimulation. Microglia/macrophage polarization modulation plays a key role in the pathogenesis of multiple sclerosis (MS)/experimental autoimmune encephalomyelitis (EAE). M1 microglia/macrophages secrete a variety of cytokines that cause inflammation and facilitate demyelination in the central nervous system (CNS). Baicalein (5,6,7-trihydroxyflavone, C 15 H 10 O 5 , BAI), a natural flavonoid isolated from the roots of the traditional Chinese medicine Scutellaria baicalensis Georgi, has been suggested to have a wide range of biological effects, including antioxidant, anti-inflammatory, and neuroprotective properties. In this study, flow cytometry, Western blotting, immunofluorescence and other methods were used to investigate whether BAI could reduce the demyelination and inflammatory response of the spinal cord in EAE mice induced by MOG 35-55 and affect the polarization of spinal microglia/macrophages. Our results showed that BAI treatment delayed the onset of EAE and alleviated clinical symptoms, demyelination and inflammatory cell infiltration. Meanwhile, BAI inhibited the overactivation of M1 microglia/macrophages in vivo and in vitro, significantly decreased the expression of proinflammatory cytokines in M1 microglia/macrophages, and inhibited the activation of STAT1. Subsequently, molecular docking, pull-down and immunofluorescence experiments confirmed that BAI has the ability to bind to the SH2 domain of STAT1 and that BAI colocalizes with p-STAT1 in the cytoplasm rather than being transferred to the nucleus during inflammatory stimulation. This study showed that BAI might inhibit the polarization of microglia/macrophages to the M1 phenotype in EAE mice by targeting STAT1. This new discovery lays a theoretical and experimental foundation for the clinical application of BAI in the treatment of MS. [ABSTRACT FROM AUTHOR]

Axially wrinkled SnO 2 /TiO 2 heteronanotubes have been successfully prepared by sacrificial template method combined with hydrothermal synthesis. The special folded morphology of SnO 2 /TiO 2 nanostructures may provide more active sites, and the S-scheme heterojunction between SnO 2 and TiO 2 enhances the separation of photogenerated electron-hole pairs, which are conducive to the improvement of photocatalytic degradation for organic pollutants. Using SnO 2 /TiO 2 nanotubes as catalyst, the removal rate of Rhodamine B (RhB), methyl orange (MO) and tetracycline hydrochloride (TCH) under the irradiation of a xenon lamp is 93%, 91% and 85%, respectively. After five cycles, the removal efficiency of organic pollutants maintains almost unchanged, indicating that the synthesized SnO 2 /TiO 2 nanotubes has good stability and reusability. In addition, trapping experiments have been carried out to investigate the major reactive oxidative species for organic pollutants photodegradation. This study provides a facile avenue to design nanotublar photocatalysts with enhanced degradation performance for organic pollutants. [ABSTRACT FROM AUTHOR]

New difluoroboron β-diketonate complexes functionalized with tert -butyl carbazole and carbazole ( TCBM and CBM ) have been synthesized, and they give strong emission in solid states with the fluorescence quantum yields of 0.63 and 0.99, respectively. Reversible mechanofluorochromic behaviors of TCBM and CBM are realized upon the treatment of grinding/fuming with CH 2 Cl 2 . Interestingly, the emitting colors of the annealed samples gained from the ground powders of TCBM depend on the heating temperature, and change from orange to yellow, yellowish green, and green with increasing temperature. The X-ray diffraction patterns illustrate that the transformation processes from crystalline structure to partial destroyed crystalline structure, till to amorphous state lead to the multi-color solid-state luminescence during thermofluorochromism. We deduced that tert -butyl can lead to the incompact packing of luminophores, which is more sensitive to external stimuli, so that multi-color solid-state luminescence can be afforded during mechanofluorochromic and thermofluorochromic processes. [ABSTRACT FROM AUTHOR]

New indolocarbazole derivatives have been synthesized via Cadogan reaction. It has been found that the reductive cyclization of 3-(2-nitrophenyl)carbazoles prefers to take place on 4-position instead of 2-position in carbazole rings. Because electrophilic substitution was one of the main steps in Cadogan reaction and the Fukui function analysis for 9-methyl-3-(2-nitrophenyl)-9 H -carbazole revealed that more positive part of f − ( r ) function was localized at 4-position than at 2-position in carbazole, the 4-position was the favorite reactive site for the reductive cyclization. Such regioselective Cadogan reaction would be useful for the synthesis of π-extended N -fused heteroacenes with desired functionalities. [ABSTRACT FROM AUTHOR]

To prepare colorless polyimides (CPIs), two novel diamines, namely 6-amino-2-(2′-methyl-4′-aminobenzene)-N-phenylbenzimidazol (5a) and 6-amino-2-(2′-trifluoromethyl-4′-aminobenzene)-N-phenylbenzimidazol (5b) were synthesized, and two series of polyimides derived from them were developed. Except for the inherent asymmetric structures, the twisted moieties had been successfully incorporated in the benzimidazole dianmines through 2′- and N-substituents. The loose chain packing and hindered charge transfer (CT) interaction caused by the askew and distorted segments provided the polyimides with excellent optical transparency (80% transmittance at 400 nm, semi-alicyclic series), while the resulting films inherited the unique superheat-resistance of poly(benzimidazole imide)s (PBIIs), e.g., high glass-transition temperatures (up to 402 °C). Such outstanding optical and thermal properties expanded their application as heat-resistant colorless materials. Furthermore, the correlation between various 2′-substituents and characters of these PBII films was systematically analyzed. These data indicated that these colorless polyimides had potential application as optical and optoelectronic materials. [Display omitted] • Two novel benzimidazole dianmines containing 2′- and N-substituents (5a and 5b) were successfully synthesized. • Polyimide films with asymmetric and twisted structures were successfully synthesized. • The semi-aromatic poly(benzimidazole imide) films achieved colorlessness (T 400 = 80–81% and T g = 394–402 °C). • The effect of various 2′-substitutions on the properties of these N-phenyl-poly(benzimidazole imide)s was investigated. [ABSTRACT FROM AUTHOR]

New triphenylvinyl substituted carbazole derivatives TPEICE , TPEC and TPECBr have been synthesized. They could self-assemble into nanofibers via organogelation processes in some organic solvents. Notably, the obtained xerogel-based films could emit strong fluorescence although the three compounds were non-emissive in solutions, indicating AIE in gel phases. The emission of TPEICE and TPEC in xerogel-based films could be quenched significantly upon exposed to gaseous DNT and TNT, while TPECBr could not sense nitro compounds on account of its poor electron donating ability. We also found that reversibility of the fluorescence response of TPEC was better than TPEICE because the photo-induced electron transfer would happen during the recognition of nitroaromatics for TPEICE and TPEC , except for the formation of charge–transfer complex between TPEICE and nitro compounds. Therefore, the different fluorescence response behaviors of TPEICE , TPEC and TPECBr towards nitroaromatics were resulted from their different electron donating abilities. [ABSTRACT FROM AUTHOR]

New branched benzothiadiazole-cored conjugated oligomers with terminal carbazoles 1 and 2 have been synthesized. It was found that no obvious shifts of the maximal absorption bands for 1 and 2 were detected in the films compared with those in solutions, indicating weak π-π stacking occurred in the solid states on account of site isolation effect of the branched architectures. Hence, the synthesized oligomers could emit strong red light in the films. Notably, the emission of the films based on 1 and 2 could be quenched obviously upon exposed to gaseous TNT and DNT. The fluorescence quenching efficiency of the oligomer 2 -based film reached 91% when exposed to the saturated vapor of DNT for 3 min at 55 °C. The linear Stern–Volmer plot and the decrease of the fluorescence lifetime of 2 induced by DNT suggested the fluorescence sensing mechanism was due to the photo-induced electron transfer. [ABSTRACT FROM AUTHOR]

The promoting effect of secondary phase particles on the refinement of matrix grains in a series of Mg–Y1.5–Nd0.6-Zn. x ( x =0, 0.2, 0.4, 0.8, 1.3) alloys deformed by friction stir processing (FSP) was investigated in this study. The volume fraction of secondary phase in the alloys increased with increment of Zn, and most of the secondary phases were broken into nano-sized particles and dispersed in the matrix during thermal mechanical processing. The resulting fine particles had a remarkable promoting effect on the grain refinement of the Mg matrix during mechanical processing, thermal deformation, and cooling with increasing volume fraction of the secondary phase. For example, the grains of Mg–Y1.5–Nd0.6–Zn1.3 alloy were refined to an average size of 28 nm, compared with the more than 100 nm grain size of the Mg–Y1.5–Nd0.6 alloy. [ABSTRACT FROM AUTHOR]

A benzoxazole derivative called BVDA was synthesized. BVDA exhibited an AIE effect although there was H-aggregated dimer in the crystal. According to the spectral results and crystal structure, the presence of excimer and the restriction of intramolecular rotation are responsible for the AIE phenomenon. Moreover, BVDA could respond to proton in solution and to volatile acid vapours in film. BVDA exhibited three colours because its binding sites to proton have different basicities. These binding sites can then be protonated in turn. These results indicate that AIE fluorophores with H-aggregated dimer is possible. Furthermore, these fluorophores can exhibit stimuli-responsive characteristics through the introduction of functional moieties. [ABSTRACT FROM AUTHOR]

Zebrafish Fish-egg lectin (zFEL) has been identified and proved to be a maternal factor with antibacterial and opsonic ability in fishes. In this study, we found that zFEL was capable of enhancing the phagocytosis of the bacteria by macrophages of mouse (RAW264.7 and mouse peritoneal macrophages), suggesting a cross-species function of zFEL in higher animals. Further studies showed that zFEL can active the antigen presentation ability by up-regulating the expression of CD80, CD86 and MHC II. Meanwhile, zFEL also promoted the polarization of macrophages to M1-type, which was confirmed by the increase of cytokines TNF-α and IL-6. The expression of p38 gene was up-regulated in macrophages preincubated with zFEL. Taken together, zFEL appears opsonic function in mammal macrophages and has potential application in immunomodulation. • Cross-species opsonic activity is found by zebrafish fish-egg lectin (zFEL) on mouse macrophages. • zFEL can up-regulate the expression of CD80, CD86 and MHC II on macrophages. • zFEL promotes the polarization of macrophages to M1-type. [ABSTRACT FROM AUTHOR]

Nowadays, there are few studies in vivo to explore the effects of Human Cytomegalovirus (HCMV) single gene such as immediate early protein 2 (IE2) on the nervous system, let alone the mechanism that IE2 causes cognitive impairment. In this study, the Rosa26-LSL-IE2/Cre mouse was used to show the effects of IE2 on the cognitive ability and the GluNRs/CaMKIIα/CREB signaling pathway in the hippocampus. We divided the mice into experimental and control groups based on the results of PCR firstly. After that, the cognitive abilities of the two groups were compared through new object recognition (NOR) and Morris water maze (MWM) tests. The results of the behavioral tests showed that the cognitive ability of the experimental mice was lower than that of the control group. It is known that changes in the expression levels of N-methyl D -aspartate receptor 1, 2A, and 2B (GluN1, GluN2A, GluN2B) affect synaptic plasticity and cause cognitive changes. Finally, we analyzed the expression levels of GluN1, GluN2A, GluN2B, and related signaling pathway molecules by qPCR and western blot. We found that the expression levels of the GluNRs/CaMKIIα/CREB signaling pathway were decreased in the experimental group. These results indicated that IE2 could affect the expression levels of GluNRs/CaMKIIα/CREB signaling pathway, which was closely related to the cognitive impairment of the experimental group. In summary, we used this novel mouse model to show that IE2 could cause cognitive impairment in the hippocampus, which might be related to the GluNRs/CaMKIIα/CREB signaling pathway. It is helpful to further understand the mechanism of the cognitive impairment induced by HCMV IE2. • Human cytomegalovirus IE2 could be stably expressed and inherited in the hippocampus of the Rosa26-LSL-IE2/Cre mice. • HCMV IE2 destroyed the structure of hippocampus in the Rosa26-LSL-IE2/Cre mouse. • HCMV IE2 caused cognitive impairment in the hippocampus. • The cognitive impairment caused by IE2 might through the GluNRs/CaMKIIα/CREB signaling pathway. [ABSTRACT FROM AUTHOR]

Highlights: [•] Synthesis of phenanthroimidazole derivatives with terminal carbazole or pyrene. [•] Photophysical properties of phenanthroimidazole derivatives. [•] Electroluminescent properties of phenanthroimidazole derivatives. [ABSTRACT FROM AUTHOR]

Abstract: Two new star-shaped difluoroboron β-diketonate complexes (TBC) 3 Ph and (TBF) 3 Ph, in which the terminal groups of triphenylamine functionalized difluoroboron β-diketonates were bridged by carbazole or fluorene to the core of 1,3,5-benzene, have been synthesized. It was found that they gave high molar extinction coefficients, meaning strong light-harvesting ability, and emitted intense yellow light with fluorescence quantum yields (Φ F) of 0.73 and 0.67 for (TBC) 3 Ph and (TBF) 3 Ph, respectively, in toluene as well as red light in solid states with Φ F of 0.36 and 0.27, respectively. The electrochemical behaviors suggested that they had considerably higher electron affinities than tris(8-hydroxyquinoline)aluminum (AlQ3), which indicated that they could be used as electron-transporting materials besides emitting materials. [Copyright &y& Elsevier]

Highlights: [•] Flesh firmness was measured instrumentally for each individual cherry. [•] Sensory panellists evaluated sweet cherry firmness using “Just-About-Right” methodology. [•] Sensory ratings were regressed against analytical firmness values. [•] The “acceptable” firmness range was 2.52–4.75N. [•] Cherries within this firmness range were acceptable by 73–92% of panellists. [ABSTRACT FROM AUTHOR]

Highlights: [•] 2,1,3-Benzothiadiazole-cored H-shaped conjugated compounds were synthesized. [•] Two-photon absorption (TPA) and two-photon induced emission properties were investigated. [•] These compounds emit red light excited by the femtosecond pulsed laser of 820nm. [•] Strong electron donor, enlarged conjugation and branched structure favored the increasing of TPA. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two fluorine (F) based oligomers are synthesized and investigated in detail. [•] F units modulate the steady-state spectra of oligomers. [•] DFT calculations analyze molecular structure and the electronic transition. [•] F units increase the TPF efficiency and the TPA cross-section of oligomers. [•] F units shorten the lifetime of excited oligomers. [Copyright &y& Elsevier]

Abstract: A modified sol–gel method was used to synthesize single-crystalline lead-free (K,Na)NbO3 (KNN) nanorods. The effects of calcination temperature and heating rate on the crystal structure and morphology were examined. At low heating rate, it was found that with increasing calcination temperature, the crystallization of KNN gradually completed and the size of the one-dimensional rods increased significantly. On the other hand, increasing heating rate changed the morphology of KNN from one-dimensional rods to cubes. The as-synthesized KNN nanorods calcined at 750°C with heating rate of 1°C/min were determined to be orthorhombic single crystals of 100–400nm wide and 1–2μm long. [Copyright &y& Elsevier]

Highlights: [•] π-Spacer dependent optical properties of fluorenone-based oligomers are studied. [•] Fluorene–ethylene (FE) spacer could modulate the steady-state spectra of oligomers. [•] DFT calculations confirm the ICT nature in the HOMO–LUMO transition. [•] FE spacer could increase the TPPL efficiency and TPA cross-section of oligomers. [•] TA measurement confirms the ICT state exists in the relaxation of excited oligomer. [Copyright &y& Elsevier]

Abstract: We compare the effects of fluorene–ethylene (FE) spacers on the photo-physical properties of fluorenone-based conjugated oligomers. The introduction of FE spacer could modulate the steady-state spectra and weaken the difference between donor-dependent spectral features. Meanwhile, the quantum chemical calculations exhibit that the electron transition mechanism modulated by FE unit is variable with the donor of oligomers. The FE π-spacer mainly rises the HOMO and facilitates the electron delocalization in the fluorene end-capped oligomer, while it lowers the LUMO and enhances the donor effect in the triphenylamine end-capped one. The time-resolved fluorescence measurement exhibits that the difference between donor-dependent excited state lifetimes of oligomers becomes less obvious after the introduction of FE units. Moreover, the nonlinear optical measurements show that the FE spacer is able to improve the two-photon fluorescence efficiency and enhance the two-photon absorption cross-section of oligomers simultaneously, but the difference in two-photon characteristics between oligomers with different donors is also decreased. [Copyright &y& Elsevier]

Abstract: We systemically investigate the photophysical properties of two star-shaped truxene based oligomers with different oligo(fluorene-vinylene) arms (Tr-OFV1 and Tr-OFV3) in solution system. The chemical quantum calculation exhibits that the electronic transition depends on the number of fluorene-vinylene (FV) groups in oligomers. The transient absorption (TA) data exhibits that increasing of FV groups in branch arms could accelerate the relaxation of excited oligomers, and the intensity-dependent exciton–exciton annihilation behavior could appear in the relaxation process of excited Tr-OFV3 and disappear in that of Tr-OFV1, indicating that their photophysical behavior is also closed to the number of FV unit. [Copyright &y& Elsevier]

Abstract: New well-defined monodisperse oligocarbazoles-functionalized anthracenes An-OCZn (n =1, 2, 3) have been synthesized through Suzuki cross-coupling reaction of the brominated oligocarbazoles and 9,10-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracene. They show good solubility in organic solvents, including dichloromethane, chloroform, toluene, ethyl acetate, and tetrahydrofuran. It should be noted that, in the case of An-OCZn, the formation of the excimer based on anthracene unit is suppressed completely due to the introduction of oligocarbazoles in 9,10-position of anthracene so that an intense blue-emitting has been afforded. In addition, the obtained An-OCZn exhibit good electrochemical and thermal stabilities. Thus, the oligocarbazoles-functionalized anthracenes can be a class of promising candidates for novel blue-emitting materials employed in OLEDs or related devices. [Copyright &y& Elsevier]

Abstract: Three new donor-π-acceptor (D-π-A) metal-free organic dyes, in which dendritic triphenylamine acts as donor, and furan, thiophene and benzene as π-linkers, were synthesized, characterized and used for the application of dye sensitized solar cell (DSSC). Among the fabricated DSSCs, the device based on the furan as π-linker exhibited a short circuit current density of 14.56 mA cm−2, an open circuit photo voltage of 0.71 V and a fill factor of 0.59, implying a power conversion efficiency (η) of 6.10%. The devices sensitized by dyes with thiophene and benzene as π-linker possessed relative lower η, 5.92% and 4.97%, respectively. [Copyright &y& Elsevier]

Abstract: Experimental and theoretical studies on the donor-dependent optical characteristics of two D–π–A–π–D type linear fluorenone-based conjugated oligomers are presented, where fluorene and triphenylamine act as the donors, respectively. Because of the strong electron-donating ability, the triphenylamine chromophores lead to red-shifts of spectral features, shorten the excited state lifetime, and enhance the two-photon fluorescence efficiency and two-photon absorption cross-section in comparison with fluorene groups. Quantum chemical calculations provide complementary information regarding the molecular structures and the frontier orbitals, which can provide a deep insight into the electronic structure and properties of oligomers. [Copyright &y& Elsevier]

Abstract: Three new triphenylamine-based dyes with Y-shaped conformation bearing triphenylamino-vinyl, 10-octyl-10H-phenothiazine-vinyl and 9-octyl-9H-carbazole-vinyl as arms (TT, TP, and TC) have been synthesized. From electrochemical investigations it is found that they can be employed in DSSCs due to the balanced HOMO and LUMO energy levels. Notably, the photo-to-electrical conversion efficiency of the DSSCs sensitized with branched TT, TP, and TC reach 5.12%, 4.84%, and 3.63%, which are higher than that sensitized with T (2.79%), and the DSSC sensitized with TT shows higher IPCE response and better photovoltaic performances (J sc=12.37mA/cm2, V oc=0.72V and ff=0.58) than others. These results reveal that the introduction of branched Y-shaped extended π-conjugated donors to D-π-A dyes cannot only enlarge the spectral response range, but also suppress the molecular aggregation on TiO2 films to a certain extent, which would enhance the performance of DSSCs. [Copyright &y& Elsevier]

Abstract: We have synthesized a series of new dipolar organic dyes Bn (n=0, 1, 2) employing triarylamine as the electron-donor, 2-cyanoacrylic acid as the electron-acceptor, and fluorenevinylene as the conjugated bridge, which were used as sensitizers in dye-sensitized solar cells. It is found that the solar-energy-to-electricity conversion efficiencies of the prepared DSSCs are in the range of 2.79–5.56%, which reach 35–70% of a standard device based on N719 fabricated and measured under the same conditions. The DSSC sensitized with B1 with balanced length of conjugated bridge shows the highest photo-to-electrical energy conversion efficiency and the open-circuit photovoltage (V oc) of 0.86 V. [Copyright &y& Elsevier]

Abstract: We point out that in theories where the gravitino mass, , is in the range (10–50) TeV, with soft-breaking scalar masses and trilinear couplings of the same order, there exists a robust region of parameter space where the conditions for electroweak symmetry breaking (EWSB) are satisfied without large imposed cancellations. Compactified string/M-theory with stabilized moduli that satisfy cosmological constraints generically require a gravitino mass greater than about 30 TeV and provide the natural explanation for this phenomenon. We find that even though scalar masses and trilinear couplings (and the soft-breaking B parameter) are of order (10–50) TeV, the Higgs vev takes its expected value and the μ parameter is naturally of order a TeV. The mechanism provides a natural solution to the cosmological moduli and gravitino problems with EWSB. [Copyright &y& Elsevier]

Abstract: Lead zirconate titanate (PZT) based piezoelectric composites embedded with ZnO nanowhiskers (ZnOw) were investigated to clarify the optimal sintering condition for densification, microstructure, and electrical properties. The samples are characterized by X-ray diffraction analysis and scanning electron microscopy. The results show that the increase of the sintering temperature and time is quite effective in improving the densification and piezoelectric properties of the PZT/ZnOw composites. However, the relative density and piezoelectric properties deteriorate as the composites are sintered over the optimal sintering condition. Particularly, the PZT/ZnOw composites sintered at 1150°C for 2h show excellent electrical properties of piezoelectric constant d 33 ∼471pC/N, relative dielectric constant ɛ ∼3838, planar electromechanical coupling factor k p ∼0.543, remnant polarization P r ∼23.2μC/cm2 and coercive field E c ∼9.2kV/cm. [Copyright &y& Elsevier]

Abstract: The electronic structures and optical properties of heavily boron (B)-doped zinc blende silicon carbide (β-SiC) have been investigated using the plane-wave pseudo-potential method with the generalized gradient approximation (GGA) based on density functional theory. The doped models Si n BC n−1 (n=4, 32) have been constructed by β-SiC unit cell. The calculated results show that the band gap of β-SiC transforms from indirect band gap to direct band gap with band gap shrink after carbon atom is replaced by boron atom. The dielectric constant of heavily B-doped β-SiC in low frequency is found to be remarkably larger, so it may act as a new dielectric material. Furthermore, after B doping, absorption peaks appear in the ultra-violet band (5–20eV) and infrared band (0–2eV). The ultra-violet absorption is similar to the undoped β-SiC. The infrared absorption would intensify with the increase of doping concentration, and absorption edge emerges redshift. [Copyright &y& Elsevier]

Agricultural products are frequently contaminated by mycotoxins; thus, the accurate detection of mycotoxins is important to food safety. Zearalenone (ZEN), a mycotoxin produced by certain Fusarium and Gibberella species, is a group III carcinogen. We developed a universal surface-enhanced Raman scattering (SERS) aptasensor for the detection of ZEN. The SERS biosensor consists of two functional nanomaterials: sulfhydryl (SH)-ZEN aptamer complementary DNA-modified Fe 3 O 4 @Au was used as a capture probe and SH-ZEN aptamer-modified Au@Ag core-shell nanoparticles served as reporter probes. In the absence of ZEN, the highest Raman signal was obtained owing to the SERS effects of Fe 3 O 4 @Au and Au@Ag core-shell nanoparticles. Conversely, the addition of ZEN triggered the release of Au@Ag core-shell nanoparticles from Fe 3 O 4 @Au, leading to a decrease in SERS intensity after magnetic separation. Hybridization of the ZEN aptamer and its complementary strand generated a strong SERS signal from the reporter probe. Moreover, preferential binding of the ZEN aptamer to ZEN was observed. The signal intensity in SERS decreased linearly when the capture probes released the reporter. For ZEN detection, a linear range from 0.005 to 500 ng mL−1, with an R2 of 0.9981, was obtained. The detection limit was 0.001 ng mL−1. The SERS aptasensor showed excellent performance for analytical applications with real-world samples (beer and wine). This study presents a new model for the detection of mycotoxins based on simple changes in aptamers. [Display omitted] • Detection of mycotoxins is important to overcome food contamination. • SERS aptasensor was developed to detect zearalenone, a group III carcinogen. • SH-cDNA-modified Fe 3 O 4 @Au as capture probe; SH-Apt-modified Au@Ag as reporter probe. • Wide linear range of 0.005–500 ng mL−1 for detecting zearalenone. • Novel model for the detection of mycotoxins to guarantee food safety. [ABSTRACT FROM AUTHOR]

Abstract: The photochromic process of nanocomposite film containing nanometer-sized Keggin type phosphotungstic acid uniformly dispersed in polyacrylamide matrix was studied by in situ AFM and spectroscopy. Under UV irradiation, the film was reduced photochemically to yield blue species. With the increase of irradiation time, the photoreduction proceeded from one-electron to two-electron blue stage. During the photochromism, the size and morphology of composite particles changed due to the cross-linked reactions of polymeric radicals. The XPS studies indicated that the chemical environment of tungsten changed and the W5+/W ratio increased as irradiation time prolonged. FT-IR results showed that the Keggin geometry of phosphotungstic acid was still preserved inside the composite during photochromism, and the interactions between polyanions and polymer matrix increased with the irradiation time. It was suggested that the degree of the photoreduction process depended on the varying of interactions between phosphotungstic acid and polymer. [Copyright &y& Elsevier]

A kind of chiral azobenzene amphiphile, N-[4-(4-dodecyloxyphenylazo)benzoyl]-l-glutamic acid (C12-Azo-l-Glu; as shown in Fig. 1), was synthesized and the self-organization properties on solid substrates were investigated. C12-Azo-l-Glu underwent a reversible trans–cis photoisomerization in dilute solution. While the photoisomerization was suppressed on solid substrate because of the H-aggregation, indicating the formation of compact film. When C12-Azo-l-Glu was cast from ethanol solution onto the hydrophilic surface of mica, a stable flat-layered structure formed spontaneously in large scale. High-resolution images allowed the identification of the relative orientation of molecular rows in the ordered thin film and the crystal lattice of mica. A molecular packing model of the layered structure was proposed. There was a template effect of mica to the self-organization process. Hydrogen bonding, π–π interaction and the chiral center in the molecule played the important roles in the self-organization process. The cooperative competitive effect between them led to the highly ordered structure. [Copyright &y& Elsevier]

A series of photochromic hybrid films were prepared through entrapping tungsten heteropolyoxometallate (PW12O403−) and molybdenum heteropolyoxometallate (PMo12O403−) in polyacrylamide (PAM) matrix, the corresponding structure and photochromic behaviors of the films were investigated with Fourier transform infrared (FT-IR), UV–Vis–near-infrared (NIR) absorption spectra (UV–Vis–NIR) and electron spin resonance (ESR). FT-IR results showed that the Keggin geometry of heteropolyoxometallate was still preserved inside the composites and strong Coulombic interaction was built between heteropolyoxometallate and PAM via hydrogen bonding. Irradiated with ultraviolet light, the transparent films changed from colorless to blue and showed reversible photochromism. The bleaching process occurred when the films were in contact with air or O2 in the dark. The molybdenum heteropolyoxometallate hybrid film had higher photochromic efficiency and slower bleaching reaction than tungsten heteropolyoxometallate hybrid film. The characteristic signals of radical and W(V) or Mo(V) in ESR spectra indicated that PAM is a hydrogen donor and the photoreduced process is in accordance with the radical mechanism. [Copyright &y& Elsevier]

A new photochromic film was prepared based on the Keggin type H3PW12O40 (PW12) with polyacrylamide (PAM) matrix. The microstructure, photochromic behavior and mechanism were investigated with FT-Infrared spectroscopy (FT-IR), atomic force microscopy (AFM), transmission electron microscopy (TEM), ultraviolet–visible absorption spectroscopy (UV–VIS), and electron resonance spectroscopy (ESR). FT-IR results showed that the Keggin geometry of PW12 was still preserved inside the matrix, and a charge-transfer bridge was built between PW12 and PAM via hydrogen bond. AFM images indicated that the surface topography of the polymer matrix changed after adding PW12. In the hybrid films, the PW12 particles had regular microstucture in nanoscale shown in TEM image. Under UV irradiation, the film was reduced photochemically to yield a blue species. With the increase of irradiation time, the photoreduction proceeded from one-electron to two-electron blue stage. The characteristic signals of W (V) and radical in ESR spectra indicated that the photoreduced process was in accordance with the radical mechanism. [Copyright &y& Elsevier]

Four new D-π-A type N,O -chelated BF 2 complexes (TCBOB , TCBTB , TCQB and TCPB) were synthesized. It was found that TCPB bearing the ligand of N -(1-pyridinyl)benzoamide shows gelation ability in methylcyclohexane, DCM/peteroleum ether, etc. The time-dependent UV–vis absorption and fluorescent emission spectral changes during the gel formation revealed that π-π interactions play important roles in the self-assembling processes. Particularly, the emission of the xerogel-based film of TCPB can be quenched by TFA (trifluoroacetic acid) vapor, and it showed high performance in the detection of TFA compared with the spin-coating films of TCBOB , TCBTB and TCQB. In addition, the BF 2 complexes exhibited reversible mechanofluorochromic behavior under the treatment of grinding/fuming or heating, and TCPB gave high-contrast mechanofluorochromism compared with others. XRD patterns in different solid states demonstrated that the external mechanical forces can induce the transformation from the crystalline to the amorphous states. Powder of TCPB was also used to image latent fingerprints on surface of glasses, and distinct fluorescent images were obtained. [Display omitted] • New BF 2 complexes were synthesized. • Gelation abilities and MFC properties of them were studied. • They were first used to detect LFP. [ABSTRACT FROM AUTHOR]