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The polymorphs of 2ClChMe‐4 in Form I (ribbon‐like crystal) and Form II (block‐like crystal) were prepared, and they exhibited curling/flipping and expansion upon heating on account of single‐crystal‐to‐single‐crystal transformations. The irreversible phase transformations occurred separately at 53.2 °C and 57.8 °C for the crystals in Form I and Form II, during which the molecular conformation of 2ClChMe‐4 changed and the molecules slipped along the (100) plane. Movement at the molecular level resulted in changes of cell parameters, which in turn led to macroscopic motions of the crystals upon heating. Additionally, the ribbon‐like crystals of 2ClChMe‐4 showed photo‐induced bending driven by [2+2] cycloaddition. Accordingly, an actuator showing reversible bending behavior was fabricated triggered by light and heat successively. Like biomimetic self‐actuators, such multi‐stimuli mechanical responsive molecular crystals might have potential applications in soft robots, artificial muscles and microfluidic systems. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease 2019 (COVID-19) is a severe infectious illness. It has been reported that COVID-19 has an effect on thyroid function. However, the association between thyroid function and prognosis of COVID-19 is still unclear. Methods: This retrospective study included patients with COVID-19 admitted to Tongji Hospital in Wuhan from January 28 to April 4, 2020. Demographic, epidemiological, clinical, laboratory, treatment, and outcome data were collected from patients with laboratory-confirmed COVID-19. Patients without history of thyroid disease who had a thyroid function test at admission were enrolled in the final analysis. Risk factors of in-hospital death were explored using univariable and multivariable Cox regression analyses. Survival differences were assessed with Kaplan–Meier curves and log-rank test. Results: A total of 127 patients were included in this study, with 116 survivors and 11 non-survivors. The serum levels of thyroid stimulating hormone (TSH) [0.8 (0.5–1.7) vs. 1.9 (1.0–3.1) μIU/mL, P =.031] and free triiodothyronine (FT3) [2.9 (2.8–3.1) vs. 4.2 (3.5–4.7) pmol/L, P <.001] were lower in non-survivors than in survivors, and a low FT3 state (defined as FT3 < 3.1 pmol/L) at admission accounted for a higher proportion in non-survivors than in survivors (72.7% vs. 11.2%, P <.001). Univariate Cox regression analysis showed that FT3 level (HR 0.213, 95% CI: 0.101–0.451, P <.001) and the low FT3 state (HR 14.607, 95% CI: 3.873–55.081, P <.001) were negatively and positively associated with the risk of in-hospital death, respectively. Furthermore, multivariate Cox regression analysis revealed that a low FT3 state was associated with an increased risk of in-hospital death after adjusting for confounding factors (HR 13.288, 95% CI: 1.089–162.110, P =.043). Moreover, Kaplan-Meier curves indicated a lower survival probability in COVID-19 patients with a low FT3 status. Conclusion: Serum FT3 level is lower in non-survivors among moderate-to-critical patients with COVID-19, and the low FT3 state is associated with an increased risk of in-hospital mortality of COVID-19. [ABSTRACT FROM AUTHOR]

As a skin-resident member of the dendritic cell family, Langerhans cells (LCs) are generally regarded to function as professional antigen-presenting cells. Here we report a simple method to visualize the endocytotic activity of LCs in living animals. BALB/c mice received subcutaneous injection of FITC-conjugated dextran (DX) probes into the ear skin and were then examined under confocal microscopy. Large numbers of FITC+ epidermal cells became detectable 12-24 hours after injection as background fluorescence signals began to disappear. Most (>90%) of the FITC+ epidermal cells expressed Langerin, and >95% of Langerin+ epidermal cells exhibited significant FITC signals. To assess intracellular localization, Alexa Fluor 546-conjugated DX probes were locally injected into IAβ-enhanced green fluorescent protein (EGFP) knock-in mice and Langerin-EGFP-diphtheria toxin receptor mice-three dimensional rotation images showed close association of most of the internalized DX probes with major histocompatibility complex (MHC) class II molecules, but not with Langerin molecules. These observations support the current view that LCs constantly sample surrounding materials, including harmful and innocuous antigens, at the environmental interface. Our data also validate the potential utility of the newly developed imaging approach to monitor LC function in wild-type animals. [ABSTRACT FROM AUTHOR]

Abstract: To meet the need for rapid and low-cost chemical sensing of explosive, new fluorescence chemosensors based on oligophenothiazines for probing vapor-phase nitro compounds have been developed. The phenothiazine-based trimer P3 and pentamer P5 have been synthesized via Heck and Wittig reactions by convergent approach. It was found that they can detect the vapors of nitro compounds, including p-nitrotoluene ( p -NT), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT) with good sensitivity and reversibility. And the sensor of P3 film gave a linear fluorescence quenching response to 7–800ppb TNT with the detection limit of 4ppb. For DNT vapor, a linear working range of the sensor was 2–24ppm with the detection limit of 40ppb. Meanwhile, the interferents, including common organic solvents, p-nitrophenol and 2,4-dinitrophenylhydrazine cannot lead to obvious fluorescence quenching, meaning that the film based on oligophenothiazines exhibited good specificity of fluorescence response to explosive. Based on the fluorescence lifetime and UV–vis absorption measurements, we suggested that the fluorescence quenching of oligophenothiazine-based films exposed to the vapors of nitro compounds was due to the formation of non-fluorescent charge-transfer complex between oligophenothiazine and nitro compounds. [ABSTRACT FROM AUTHOR]

Abstract: Two-component organogelators based on a discotic H-bonding donor of 1,3,5-tris(4-amidobutanoic acid)phenyl benzene (2), and acceptors of 4-(4-alkoxybenzoyloxy)-4′-stilbazole derivatives were reported. These complexes showed good gelation ability for alcohols, which are known to be unfavorable for H-bonding formation. SEM study revealed that sheet-like network, nanotapes, and nanorods were gained from the self-assembling of the complexes with small difference of the carbon chain length. Based on XRD, IR, temperature-dependent 1H NMR, and UV–vis absorption investigations, the gel-phase materials were generated from 1D columnar-type packing of complexes facilitated by cooperative H-bonding, π-stacking, and van der Walls interactions. [Copyright &y& Elsevier]

Abstract: Motivated by specific connections to dark matter signatures, we study the prospects of observing the presence of a relatively light gluino whose mass is in the range with a wino-like lightest supersymmetric particle with mass in the range of . The light gaugino spectra studied here is generally different from other models, and in particular those with a wino dominated LSP, in that here the gluinos can be significantly lighter. The positron excess reported by the PAMELA satellite data is accounted for by annihilations of the wino LSP and their relic abundance can generally be brought near the WMAP constraints due to the late decay of a modulus field re-populating the density of relic dark matter. We also mention the recent FERMI photon constraints on annihilating dark matter in this class of models and implications for direct detection experiments including CDMS and XENON. We study these signatures in models of supersymmetry with non-minimal soft breaking terms derived from both string compactifications and related supergravity models which generally lead to non-universal gaugino masses. At the LHC, large event rates from the three-body decays of the gluino in certain parts of the parameter space are found to give rise to early discovery prospects for the gaugino sector. Excess events at the 5 sigma level can arise with luminosity as low as at a center of mass energy of 10 TeV and at . [Copyright &y& Elsevier]

Fluorine-free chalcones and chalcones bearing different numbers of fluorine atoms have been synthesized. It is found that fluorine can tune the reactivity of photo-induced [2 + 2] cycloaddition reactions in crystals. The higher the number of fluorine atoms, the higher the reactivity of the photodimerization. The single crystal structures and Hirshfeld surface analysis illustrated that the introduction of fluorine not only increased the molecular planarity but could also steer the potentially reactive double bonds in appropriate positions of the crystal lattices to meet Schmidt's criteria. Therefore, the stereospecific [2 + 2] cycloaddition reactions took place to afford one diastereoisomer from the reactive chalcones except for (E)-3-(4-fluorophenyl)-1-phenylprop-2-en-1-one (1FChH). Additionally, the chalcone-based molecular crystals exhibited various photomechanical behaviors, such as bending toward or away from the light source, swinging, cracking and jumping, driven by topo-photoreactions. As expected, the more efficient photo-induced [2 + 2] cycloaddition reactions in crystalline states led to more significant motions of the molecular crystals. Powder X-ray diffraction results suggested that the solid state [2 + 2] cycloaddition reactions changed the unit cell of the single crystals. The photo-induced bending toward or away from the light source for the needle-like crystals originated from the contraction or the expansion of the phototropic surface. Hence, the robust balancer fluorine in chalcones might play an important role in the crystalline packing. This provides a facile approach in crystal engineering to fabricate photo-induced mechanically responsive crystalline materials. [ABSTRACT FROM AUTHOR]

Abstract: We report on the synthesis and self-assembly of a new discotic organogelator based on π-conjugated triphenylbenzene with three peripheral chiral substituents. It is found that the introduction of chiral groups to the C 3-symmetric molecule led to a hexagonal columnar chiral stacking of the molecules in a clockwise direction in the organogel fibers. And the fluorescent emission of the gel decreased significantly compared to the monomer state at the same concentration, as a result of the aggregation of the nonplanar triphenylbenzene core in the gel phase. [Copyright &y& Elsevier]

Abstract: This paper presents novel organogelators based on long chain substituted benzoic acid hydrazine which can form stable gels in bulk organic solvents and self-assemble into various microstructures in organogel phases. It is found that hydrogen bonding and van der Waals interaction play an important role on the formation of organogel. [Copyright &y& Elsevier]

Abstract: This paper presents a novel method for the preparation of copper sulfide (CuS) nanotubes using hydrogel based on N-lauroylalanine as template under mild condition. The resulting samples are examined by transmission electron microscopy (TEM) FT-IR spectroscopy, X-ray powder diffraction (XRD), UV–vis absorption spectroscopy. It is found that the intermolecular hydrogen bonds play an important role on the formation of the hydrogel and the Cu2+ coordination gel. The formation process of CuS nanotube is also discussed. [Copyright &y& Elsevier]

Triphenyl pyrazoline derivatives (TPPs) bearing electron withdrawing and pushing substitutents were synthesized. Their photoluminescence (PL) properties in the solution and doped in poly(N-vinylcarbazole) (PVK) thin films were investigated. When TPPs were doped into PVK films the photoluminescence intensity was enhanced with increasing TPPs concentration. It indicated that the energy transfer from PVK to TPPs has happened. Double and three-layer electroluminescence (EL) devices based on PVK doped with TPPs as an active layer were fabricated and investigated and the electroluminescent mechanism was followed by energy transfer from PVK to TPPs. The pyrazoline derivative with both electron withdrawing and pushing substituents was the optimistic candidate for electroluminescent emitter due to higher transfer efficiency from electric energy to light energy as well as larger luminance. [Copyright &y& Elsevier]

Highly stable, uniform, and monodisperse Au nanoparticles, protected by hyperbranched poly(amine-ester) (HPAE-5), were prepared by reducing HPAE-5/hydrogen tetrachloroaurate using sodium borohydride in aqueous solution. UV-visible absorption, Fourier transform infrared spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and electron diffraction (ED) have been used to study the structure and characterization of the nanocomposites. From which, it can be suggested that Au nanoparticles are formed inside HPAE-5 and located offset from the center, besides that the distribution of Au nanoparticles is narrow. The simple procedure and good results allow for a complete understanding of previous reported difficulties in preparing Au nanoparticles by wet method. [Copyright &y& Elsevier]

Three push–pull type azo dyes, 4′-{[(2-hydroxylethyl)methyl]amino}-4-nitroazobenzene (compound I), 1-[4-(4′-nitrophenyl)-azophenyl]-3,5-biphenyl-2-pyrazoline (compound II) and 1-[4-(4′-nitrophenyl)-azophenyl]-3-(3′-trifluoromethyl)-phenyl-5-phenyl-2-pyrazoline (compound III) were synthesized. The cis–trans isomerization process and polarized photoinduced birefringence of those azo dyes doped PMMA films were investigated. It was found that the rise and relaxation process of birefringence signals were fit with biexponential functions and the molecular structures have effects on their photo-induced birefringence. This suggests that the three films have similar storage speed when the laser intensity is high enough. Compound III, which has the biggest substituent, has the largest long-term storage ability and can even keep 90% of its saturated birefringence. [Copyright &y& Elsevier]

1-D nanorods, twinrods, golfclubs, and tripods of CdS were prepared via a surfactant–ligand co-assisted solvothermal method at 160°C. The surfactant of S-dodecylisothiounium bromide (C12) used in the process was favorable for synthesis of different-shaped CdS nanorod with high aspect ratio. X-ray diffraction (XRD) and TEM images showed that the 1-D nanorods had wurtzite phase and others had a zinc blende core and wurtzite arms. The morphologies of CdS prepared under different conditions suggested the “template-assistance” of the surfactant and that the nonaqueous organic media are important for the self-assembling of inorganic components at atomic level. [Copyright &y& Elsevier]

Two azo-containing polymers with pyrazoline group (polymers II and III) have been synthesized and their reversible optical storage properties tested in comparison with electron donor and acceptor substituted azobenzene-containing polymer I. The growth and relaxation process of birefringence signals were fit with biexponential functions. It was found that polymer II, in which azo chromophores are connected with the main chain through pyrazoline groups, has fast storage rate and good storage stability. The storage efficiency indicated that the introduction of pyrazoline groups in the polymers II and III has a positive effect. The birefringence per mole of azo chromophore showed that polymers II and III have four times the value of polymer I. The relative stability of the photoinduced birefringence decreased with the increase of temperature. [Copyright &y& Elsevier]

Au nanoparticles were prepared by reduction of HAuCl4 with NaBH4 in the presence of generation 1.5 poly(amidoamine) dendrimers with surface hydroxyl groups (OH-PAMAM-1.5). By optimizing the conditions of the preparation, stable, and uniform Au nanoparticles of 2.7±0.5 nm were obtained. UV-Vis absorption, Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and electron diffraction (ED) have been used to study the structure and characterization of the nanocomposites. From which, it could be suggested that Au nanoparticles were surrounded by OH-PAMAM-1.5 and the size distribution of Au nanoparticles is narrow. [Copyright &y& Elsevier]

A novel photochromic gel film was prepared through entrapping 12-phosphotungstic acid (PWA) into a kind of inorganic–organic matrix co-hydrolyzed from tetraethylorthosilicate (TEOS) and 3-aminopropyltriethoxysilane (APTES). Infrared (IR) spectra revealed that the Keggin structure characteristic of PW12O403− anions was present in the amine-functionalized silica gel skeleton and PWA interacted with R-NH3+ cations strongly. The amorphous state of the gel film was proved by X-ray diffraction (XRD) pattern. The gel film exhibited reversible photochromicity. Irradiated with ultraviolet light, the transparent film changes from colorless to blue. Then, bleaching occurs when the film is in contact with air or O2 in the dark. [Copyright &y& Elsevier]

A self-assembled layered superlattice composite film was fabricated by casting the chloroform solutions of ionic complex between dioctadecyldimethylammonium (DODA) and 18-molybdophosphate anion (P2Mo186−) onto CaF2, borosilicate glass, and quartz substrates. Infrared and UV spectra revealed that the Dawson structure characteristic of P2Mo186− was preserved in the composite film. A well-ordered superlattice structure was identified by X-ray diffraction (XRD). From XRD results and the cross-sectional area of DODA cation and P2Mo18 polyanion, a possible structural model was proposed. The P2Mo18/DODA film showed good photochromic properties. Irradiated with UV light, the transparent film changed from light yellow to blue. Then, bleaching occurred when the film was in contact with ambient air or O2 in the dark. A possible photochromic mechanism was proposed according to electron spin resonance (ESR), Fourier transform infrared (FTIR) spectra, and UV–Vis spectra. [Copyright &y& Elsevier]

A novel thermochromic sol–gel film has been prepared for the first time through entrapping phosphomolybdic acid into a kind of inorganic–organic matrix co-hydrolyzed from tetraethylorthosilicate and 3-aminopropyltriethoxysilane. The thus-obtained amorphous nanocomposite film was characterized by IR spectra, UV–vis absorption spectra, XRD, TG–DTA, and ESR. Results show that phosphomolybdate polyanions interact with R–NH+3 cations strongly and disperse homogeneously in the sol-gel matrix. The sol–gel film exhibits thermochromic properties. Annealed from 120 to 180°C, the transparent film changes from pale-yellow to blue. A possible charge-transfer process has been suggested to explain the thermochromism. [Copyright &y& Elsevier]

• PELP1 was upregulated during PDLSCs osteogenic differentiation. • Runx2 expression and ERK phosphorylation were controlled by PELP1 in PDLSCs. • ERK inhibition restrained PELP1 induced Runx2 expression in PDLSCs. The aim of this study was to determine the physiological function and mechanism of proline-, glutamic acid-, and leucine-rich protein 1 (PELP1) in the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) at the molecular level in vitro. During the osteogenic differentiation of hPDLSCs, the change of PELP1 and the osteogenic commitment markers runt-related transcription factor 2(RUNX2), alkaline phosphatase (ALP) and osteocalcin (OCN) were monitored by quantitative real-time PCR (qRT-PCR) and western blots. To elucidate how PELP1 regulates RUNX2 , the expression of RUNX2 , the phosphorylation of extracellular regulated protein kinases (ERK) and subcellular location of PELP1 were detected under conditions that PELP1 was either knockdown by specific siRNA or overexpressed. A pharmacological inhibitor of ERK, U0126 was used while PELP1 was overexpressed, and the expression of RUNX2 was monitored by qRT-PCR. PELP1 was upregulated during the osteogenic differentiation of hPDLSCs. Knockdown of PELP1 suppressed the expression of RUNX2 , whereas overexpression of PELP1 increased RUNX2 expression. Moreover, PELP1 knockdown resulted in reduced ERK phosphorylation and RUNX2 expression, and PELP1 overexpression induced RUNX2 expression was inhibited by U0126 in the hPDLSCs. PELP1 regulates the expression of RUNX2 during the osteogenic differentiation of hPDLSCs and that the ERK pathway is involved in this process. [ABSTRACT FROM AUTHOR]

• Superhydrophilic nanostructure was fabricated for improving soft tissue sealing. • The properties of the surface regulate the behavior of human gingival fibroblasts. • FAK/integrin-mediated adhesion seemed to be induced by the hydrogenated surface. Soft tissue integration is critical for the long-term retention of dental implants. The surface properties including topography and wettability can impact soft tissue sealing. In our work, a thermal hydrogenation technique was applied to modify anodized titanium dioxide nanotubes (TNTs). However, the effects of the hydrogenated surface on soft-tissue cells remain unclear. The aim of the present study was to investigate the bioactivities of human gingival fibroblasts (HGFs) on structured surfaces, which determine the early formation of soft tissue sealing. Three groups were examined: commercially pure titanium (Ti), anodized TNTs (air-TNTs) and hydrogenated TNTs (H 2 -TNTs). Scanning electron microscopy showed the nanotubular topography on the titanium surfaces after anodization. Then, hydrogenation ensured that the H 2 -TNTs were superhydrophilic with a contact angle of 3.5 ± 0.8°. In vitro studies such as cell adhesion assays, cell morphology, immunocytochemistry, wound healing assays, real-time PCR and enzyme-linked immunosorbent assays displayed enhanced adhesion, migration, relative gene expression levels, and extracellular matrix synthesis of the HGFs on H 2 -TNTs. Interestingly, focal adhesion kinase activation and integrin-mediated adhesion seemed to be induced by the H 2 -TNT surface. Our results revealed that a superhydrophilic nanostructure modified by anodization and hydrogenation can improve the bioactivity of HGFs and connective tissue regeneration, which will further promote and expand the application of titanium dioxide nanotubes in dental implants. [ABSTRACT FROM AUTHOR]

Sustained changes in mood or action require persistent changes in neural activity, but it has been difficult to identify the neural circuit mechanisms that underlie persistent activity and contribute to long-lasting changes in behavior. Here, we show that a subset of Doublesex+ pC1 neurons in the Drosophila female brain, called pC1d/e, can drive minutes-long changes in female behavior in the presence of males. Using automated reconstruction of a volume electron microscopic (EM) image of the female brain, we map all inputs and outputs to both pC1d and pC1e. This reveals strong recurrent connectivity between, in particular, pC1d/e neurons and a specific subset of Fruitless+ neurons called aIPg. We additionally find that pC1d/e activation drives long-lasting persistent neural activity in brain areas and cells overlapping with the pC1d/e neural network, including both Doublesex+ and Fruitless+ neurons. Our work thus links minutes-long persistent changes in behavior with persistent neural activity and recurrent circuit architecture in the female brain. [ABSTRACT FROM AUTHOR]

A Ni-catalyzed Suzuki-type cross-coupling of boronic acids with epoxides without an exogenous base and with broad substrate scope has been developed. The product selectivity of styrenyl epoxides is different from that of previous work. This methodology uses readily available starting materials to access a range of substituted alcohols, which are valuable feedstock chemicals. [ABSTRACT FROM AUTHOR]

The phloem, located within the vascular system, is critical for delivery of nutrients and signaling molecules throughout the plant body. Although the morphological process and several factors regulating phloem differentiation have been reported, the molecular mechanism underlying its initiation remains largely unknown. Here, we report that the small peptide‐coding gene, CLAVATA 3 (CLV3)/EMBEYO SURROUNDING REGION 25 (CLE25), the expression of which begins in provascular initial cells of 64‐cell‐staged embryos, and continues in sieve element‐procambium stem cells and phloem lineage cells, during post‐embryonic root development, facilitates phloem initiation in Arabidopsis. Knockout of CLE25 led to delayed protophloem formation, and in situ expression of an antagonistic CLE25G6T peptide compromised the fate‐determining periclinal division of the sieve element precursor cell and the continuity of the phloem in roots. In stems of CLE25G6T plants the phloem formation was also compromised, and procambial cells were over‐accumulated. Genetic and biochemical analyses indicated that a complex, consisting of the CLE‐RESISTANT RECEPTOR KINASE (CLERK) leucine‐rich repeat (LRR) receptor kinase and the CLV2 LRR receptor‐like protein, is involved in perceiving the CLE25 peptide. Similar to CLE25, CLERK was also expressed during early embryogenesis. Taken together, our findings suggest that CLE25 regulates phloem initiation in Arabidopsis through a CLERK‐CLV2 receptor complex. [ABSTRACT FROM AUTHOR]

The development of the economy and society makes heavy metals (HMs) pollution more and more serious. And, pollution source identification is the primary work of environmental pollution control and land planning. Notably, stable isotope technology has a high ability to distinguish pollution sources, and can better reflect the migration behavior and contribution of HMs from diverse sources, which has become a hot research tool for pollution source identification of HMs. Currently, the rapid development of isotope analysis technology provides a relatively reliable reference for pollution tracking. Based on this background, the fractionation mechanism of stable isotopes and the influence of environmental processes on isotope fractionation are reviewed. Furthermore, the processes and requirements for the measurement of metal stable isotope ratios are summarized, and the calibration methods and detection accuracy of sample measurement are evaluated. Besides, the current commonly used binary model and multi-mixed models in the identification of contaminant sources are also concluded. Moreover, the isotopic changes of different metallic elements under natural and anthropogenic conditions are discussed in detail, and the application prospects of multi-isotope coupling in the traceability of environmental geochemistry are evaluated. This work has some guidance for the application of stable isotopes in the source identification of environmental pollution. [Display omitted] • The mechanism of isotopic fractionation needs to be further investigated. • Isotopic techniques have limitations in terms of source contribution calculation. • The overlap of isotopic compositions reduces the accuracy of identification results. • Isotopic techniques are able to identify the sources of HMs in different media. • Combining multiple isotopes could improve the accuracy of traceability results. [ABSTRACT FROM AUTHOR]

Removing noxious dyes and detecting excessive metal ions in water are both effective means to prevent damage from contaminants and ensure water safety. The emphasis problems were addressed by preparation a polyacrylamide chitosan (PAAM/CS) hydrogel. Polyacrylamide (PAAM) provides overall mechanical strength to carry loads and facilitate circulation, chitosan (CS) provides adsorption positions with high adsorption capacity. Which made that PAMM/CS hydrogel efficiently performed sorption of xylenol orange (XO). As the functional dye, XO binds to PAAM/CS and confers colorimetric properties on PAAM/CS hydrogels. XO sorbed hydrogel realized fluorescence dual-signal detection of Fe3+ and Al3+ in water. The significant swelling and adsorption potency of the hydrogel, combined with the dual-signal detection capability of XO sorbed hydrogel, make this hydrogel a versatile material for environmental applications. • Polyacrylamide chitosan hydrogel was prepared as adsorbent. • Adsorption mechanism is mainly based on electrostatic attraction. • After five adsorption cycles, the composite hydrogel still achieved 83.29 % removal of xylenol orange. • XO sorbed hydrogel realized fluorescence dual-signal detection of Fe3+ and Al3+ in water. [ABSTRACT FROM AUTHOR]

Food safety is one of the greatest public health challenges. Developing ultrasensitive detection methods for analytes at ultra-trace levels is, therefore, essential. In recent years, the bio-barcode assay (BCA) has emerged as an effective ultrasensitive detection strategy that is based on the indirect amplification of various DNA probes. This review systematically summarizes the progress of fluorescence, PCR, and colorimetry-based BCA methods for the detection of various contaminants, including pathogenic bacteria, toxins, pesticides, antibiotics, and other chemical substances in food in over 120 research papers. Current challenges, including long experimental times and strict storage conditions, and the prospects for the application of BCA in biomedicine and environmental analyses, have also been discussed herein. [Display omitted] • Bio-barcode assay (BCA) is a novel rapid detection technology. • BCA has several advantages over conventional methods. • We summarize the concept and detection principles of BCA. • BCA has extensive applications in food testing. [ABSTRACT FROM AUTHOR]

Triphenylamine functionalized salicylaldimine difluoroboron complexes bearing different substituents have been synthesized. The photophysical results showed that these complexes exhibited intramolecular charge transfer (ICT) emission and solvatochromism. The fluorescence of these complexes could be well-tuned by the substituents in the ligands. The introduction of tert-butyl groups causes the complex TST to show obvious aggregation-induced emission (AIE) activity. In particular, the complexes without other substitutions or with the substitutions of bromo, tert-butyl and methoxyl on salicylaldimine moieties displayed reversible mechanofluorochromic (MFC) behaviors. XRD patterns and DSC curves of the complexes in different solid states suggested that the transformation between crystalline and amorphous states was responsible for the MFC properties. The relationship between the molecular structures and MFC properties suggested that the high polarity of the conjugated skeletons in difluoroboron complexes was beneficial for realizing high-contrast performance in mechanofluorochromism. [ABSTRACT FROM AUTHOR]

Spirofluorene‐cored bis(difluoroboron β‐diketonate) complexes bearing terminal carbazoles (CbzBSF) and tert‐butylcarbazoles (TCbzBSF) have been synthesized. It was found that only TCbzBSF could form organogels in cyclohexane and methylcyclohexane, suggesting that tert‐butylcarbazole was essential for its organogelation directed by weak π–π interactions. It is worth noting that TCbzBSF could entrap ca. 5800 molecules of methylcyclohexane per gelator molecule, so this fully conjugated complex without traditional gelation group could be considered as a supergelator. The gained organogel showed reversible thixotropic and temperature‐dependent sol‐gel transitions. In particular, the orange red fluorescence of the xerogel‐based film of TCbzBSF could be quenched when exposed to gaseous aromatic amines of aniline, N‐methylaniline, and N,N‐dimethylaniline. The detection limit for aniline vapor of the xerogel‐based film was as low as 0.56 ppb. [ABSTRACT FROM AUTHOR]

Abstract New D-π-A type quinoline derivatives (CbzVQ and TPAVQ) were synthesized via Knoevenagel condensation reactions. They exhibited reversible high-contrast mechanofluorochromic (MFC) behavior under grinding/fuming treatment. Taking CbzVQ as an example, its fluorescence could be switched from blue to greyish green by grinding the as-synthesized sample into ground powders, and the fluorescence emission was red-shifted from 449 nm (with shoulders at 475 nm and 520 nm) to 578 nm (with shoulders at ca. 450 nm and 500 nm). Such large shift of the maximal emission peak during MFC processes was rare reported. In addition, the casting films of CbzVQ and TPAVQ emitted blue and green light, respectively, which was turned to red rapidly induced by TFA (trifluoroacetic acid) vapor. Moreover, the emission could be recovered stimulated by TEA (triethylamine) vapor, so the quinoline derivatives exhibited reversible fluorescent sensory properties. TPAVQ showed better performance in the detection of TFA vapor than CbzVQ due to the strong electron-donating ability of triphenylamine compared with carbazole. The detection limit and the decay time of TPAVQ towards TFA vapor were 163 ppb and 0.22 s, respectively. Apparently, the D-π-A type quinoline derivatives are candidates as multi-stimuli responsive fluorescent materials. Graphical abstract Image 1 Highlights • New D-π-A type quinoline derivatives bearing carbazole and triphenylamine are synthesized. • Quinoline derivatives show reversible high-contrast mechanofluorochromism. • The shift of the maximal emission for CbzVQ reaches 129 nm during mechanofluorochromic processes. • The emitting color of quinoline derivatives is turn to red from blue or green rapidly stimulated by TFA vapor. [ABSTRACT FROM AUTHOR]

Neural circuits can be reconstructed from brain images acquired by serial section electron microscopy. Image analysis has been performed by manual labor for half a century, and efforts at automation date back almost as far. Convolutional nets were first applied to neuronal boundary detection a dozen years ago, and have now achieved impressive accuracy on clean images. Robust handling of image defects is a major outstanding challenge. Convolutional nets are also being employed for other tasks in neural circuit reconstruction: finding synapses and identifying synaptic partners, extending or pruning neuronal reconstructions, and aligning serial section images to create a 3D image stack. Computational systems are being engineered to handle petavoxel images of cubic millimeter brain volumes. [ABSTRACT FROM AUTHOR]

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]

New D–π–A type phenothiazine-modified 2-hydroxychalcone analogues PTNn (n = 2, 4, 8, 12, and 16) have been synthesized, and they exhibited reversible mechanofluorochromism. Notably, the emission of PTNn in different solid-states was in the range of 600–800 nm, and red-emitting mechanofluorochromic (MFC) materials were seldom reported. The as-synthesized crystals of PTN16 emitted red light centered at 667 nm, and were changed into deep red emitting ground powders after grinding. The fluorescence emission could be recovered to the original state when the ground powders were fumed with the DCM vapor or heated. The MFC processes were accompanied by the transformation between crystalline and amorphous states, which could be confirmed based on the results of XRD patterns in different solid-states. Additionally, it was found that the length of the alkyl chain affected the performance in mechanofluorochromism for PTNn. The dye bearing a short carbon chain showed high-contrast MFC behavior compared with the one bearing a long carbon chain. Moreover, PTN12 and PTN16 bearing long carbon chains could self-assemble into organogels in a certain amount of organic solvents, and gelation-induced emission enhancement was observed during organogelation. [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 D–π–A-type triphenylamine-containing benzimidazoles, benzoxazoles and benzothiazoles have been synthesized. It was found that the introduction of a cyano group in vinyl and methyl in triphenylamine was favorable for producing mechanofluorochromism of the fused heterocyclic derivatives. The single crystal X-ray diffraction data revealed that the intermolecular interactions of the H-bonding formed from the cyano group and the C–H…π interaction formed from the methyl group would rigidify the molecular conformations, leading to strong solid-state emission. Interestingly, the solid-state emission of the synthesized triphenylamine-containing fused heterocycles bearing cyano and/or methyl groups could be tuned by external mechanical forces on account of the transition between crystalline and amorphous states or between a highly ordered crystalline state and a less ordered state. [ABSTRACT FROM AUTHOR]

Somatic polyploidy caused by endoreplication is observed in arthropods, molluscs, and vertebrates but is especially prominent in higher plants, where it has been postulated to be essential for cell growth and fate maintenance. However, a comprehensive understanding of the physiological significance of plant endopolyploidy has remained elusive. Here, we modeled and experimentally verified a high-resolution DNA endoploidy map of the developing Arabidopsis thaliana root, revealing a remarkable spatiotemporal control of DNA endoploidy levels across tissues. Fitting of a simplified model to publicly available data sets profiling root gene expression under various environmental stress conditions suggested that this root endoploidy patterning may be stress-responsive. Furthermore, cellular and transcriptomic analyses revealed that inhibition of endoreplication onset alters the nuclear-to-cellular volume ratio and the expression of cell wall-modifying genes, in correlation with the appearance of cell structural changes. Our data indicate that endopolyploidy might serve to coordinate cell expansion with structural stability and that spatiotemporal endoreplication pattern changes may buffer for stress conditions, which may explain the widespread occurrence of the endocycle in plant species growing in extreme or variable environments. [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]

Abstract: An alkoxyl radical guided strategy for site‐selective functionalization of unactivated methylene and methine C−H bonds enabled by an FeII‐catalyzed redox process is described. The mild, expeditious, and modular protocol allows efficient remote aliphatic fluorination, chlorination, amination, and alkynylation of structurally and electronically varied primary, secondary, and tertiary hydroperoxides with excellent functional‐group tolerance. The application for one‐pot 1,4‐hydroxyl functionalization of non‐oxygenated alkane substrates initiated by aerobic C−H oxygenation is also demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: An alkoxyl radical guided strategy for site‐selective functionalization of unactivated methylene and methine C−H bonds enabled by an FeII‐catalyzed redox process is described. The mild, expeditious, and modular protocol allows efficient remote aliphatic fluorination, chlorination, amination, and alkynylation of structurally and electronically varied primary, secondary, and tertiary hydroperoxides with excellent functional‐group tolerance. The application for one‐pot 1,4‐hydroxyl functionalization of non‐oxygenated alkane substrates initiated by aerobic C−H oxygenation is also demonstrated. [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]

Abstract: New diarylethene derivatives containing benzoxazole (NBO) and benzothiazole (NBT) have been synthesized. Light‐induced trans–cis isomerization of NBO and NBT took place in crystals, and only induced the needle‐like crystals of NBO to bend backwards away from the UV light source. The movement of the atoms was deemed to take place during the isomerization of NBO; hence, strain would be produced and accumulated rapidly in the surface of crystals exposed to UV light. The uniform release of strain led to the bending of needle‐like crystals. The light‐induced trans–cis isomerization efficiency of NBT was too low to drive the motion of crystals, which might have originated from the large repulsion between naphthyl and benzothiazole. These results provide a new platform for the transformation of light energy into mechanical energy in molecular crystals through the unimolecular photochemical reaction of diarylethene derivatives. [ABSTRACT FROM AUTHOR]

Novel luminescent organogelators based on nucleoside functionalized with carbazole (UC8, UC12 and UC16) were designed and synthesized. Their gelation ability was tested and it was found that both UC12 and UC16 could form stable organogels in toluene/petroleum ether. The UV-vis absorption, fluorescence emission and IR spectral changes during the gelation of UC12 proved that the self-assembly was driven by H- bonding. The morphology of the xerogel UC16 obtained from toluene/petroleum ether (v/v = 1/1) displayed tough rod-like microstructures, and 3D networks formed from lots of nanofibers were observed for the xerogel UC16 obtained from toluene/petroleum ether (v/v = 2/1). It was interesting that the obtained organogels emitting blue light could be destroyed by the addition of F-, accompanied with the declining the emission intensity. Therefore, these organogels could be used as sensory materials to recognize F-. [ABSTRACT FROM AUTHOR]

Aims: To perform a meta‐analysis of randomized controlled trials (RCTs), including 6 recently published large‐scale cardiovascular outcome trials (CVOTs), to evaluate the risk of pancreatic cancer with incretin‐based therapies in patients with type 2 diabetes (T2DM). Materials and Methods: For the period January 1, 2007 to May 1, 2017, the PubMed, Embase, Cochrane Central Register and ClininalTrials.gov databases were searched for RCTs in people with T2DM that compared incretin drugs with placebo or other antidiabetic drugs, with treatment and follow‐up durations of ≥52 weeks. Two reviewers screened the studies, extracted the data and assessed the risk of bias independently and in duplicate. Results: A total of 33 studies (n = 79 971), including the 6 CVOTs, with 87 pancreatic cancer events were identified. Overall, the pancreatic cancer risk was not increased in patients administered incretin drugs compared with controls (Peto odds ratio [OR] 0.67, 95% confidence interval [CI] 0.44‐1.02). In the 6 CVOTs, 79 pancreatic cancer events were identified in 55 248 participants. Pooled estimates of the 6 CVOTs showed an identical tendency (Peto OR 0.65, 95% CI 0.42‐1.01). Notably, in the subgroup of participants who received treatment and follow‐up for ≥104 weeks, 84 pancreatic cancer events were identified in 59 919 participants, and a lower risk of pancreatic cancer was associated with incretin‐based therapies (Peto OR 0.62, 95% CI 0.41‐0.95). Conclusions: Treatment with incretin drugs was not associated with an increased risk of pancreatic cancer in people with T2DM. Instead, it might protect against pancreatic malignancy in patients treated for ≥104 weeks. [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]