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Background Bladder cancer (BCa) is a common genitourinary malignancy with higher incidence in males. Long intergenic non-protein coding RNA 265 (LINC00265) is identified as an oncogene in many malignancies, while its role in BCa development remains unknown. Purpose To explore the functions and mechanism of LINC00265 in BCa Research Design Reverse transcription quantitative polymerase chain reaction was performed to examine LINC00265 expression in BCa cells. Cell counting kit-8 assays, colony formation assays, TdT-mediated dUTP Nick-End Labeling assays, and Transwell assays were conducted to examine BCa cell viability, proliferation, apoptosis, and migration. Luciferase reporter assays and RNA immunoprecipitation assays were carried out to explore the binding capacity between miR-4677-3p and messenger RNA fibroblast growth factor 6 (FGF6) (or LINC00265). Xenograft tumor model was established to explore the role of LINC00265 in vivo. Results LINC00265 was highly expressed in BCa cells. LINC00265 knockdown inhibited xenograft tumor growth and BCa cell viability, proliferation and migration while enhancing cell apoptosis. Moreover, LINC00265 interacted with miR-4677-3p to upregulate the expression of FGF6. FGF6 overexpression reversed the suppressive effect of LINC00265 knockdown on malignant phenotypes of BCa cells. Conclusions LINC00265 promotes the viability, proliferation, and migration of BCa cells by binding with miR-4677-3p to upregulate FGF6 expression.

Intracellular pH has a significant influence on cell metabolism and various physiological activities. Therefore, there is an urgent need for a chemical sensor with excellent performance for intracellular pH-sensitive detection, which is extremely helpful for further understanding of related physiological and pathological processes. In this work, a ratiometric fluorescent probe, (1-(pyren-1-yl)-3-(pyridine-3-yl)-acrylketone (PPAK), was synthesized by the condensation reaction of 1-acetylpyrene and 3-pyridinecarboxaldehyde. PPAK has been used to detect extremely acidic and extremely alkaline pH in aqueous solutions. The recognition mechanism of PPAK depended on the protonation of the pyridine groups under acidic conditions and the attack of hydroxyl toward the carbonyl group to break down the conjugated structure under alkaline conditions, respectively. PPAK also exhibited favorable properties including outstanding photostability, excellent selectivity, rapid response and large stokes shift (166 nm). Finally, the results of E. coli cells imaging demonstrated its applicability in monitoring the pH changes in living cells.

Three cross-conjugated chalcone derivatives T3CT, T3CP2, and T3CP3 were designed and synthesized to develop excellent organic nonlinear optical (NLO) materials. In a Z-scan experiment, all compounds show good NLO absorption characteristics in the visible to near-infrared region. The photophysical mechanism is confirmed to be two-photon absorption (TPA)-induced excited-state absorption (ESA). Intramolecular charge transfer (ICT) observed in transient absorption spectra (TAS) significantly affects molecular NLO properties. We define the π-conjugated system that dominates the electron transition process in the cross-conjugated structure as the effective π-conjugated structure. Electron transition analysis shows a sufficiently strong ICT can effectively expand the effective π-conjugated structure in these cross-conjugated structures. The TPA cross sections of these compounds at 650 and 750 nm are only in the range of 17-97 GM. However, we achieve a significant enhancement of the TPA cross section at 580 nm (1737-2027 GM) by extending the effective π-conjugated structure. Excited by 580 nm femtosecond laser pulses, all compounds exhibit excellent OL performance and the minimum OL threshold is 4.71 × 10-3 J/cm2. The results show that these cross-conjugated chalcone derivatives have promising applications in OL, and their NLO performance can be effectively improved by modulating the effective π-conjugated structure.

A new type of cross-linked copolymer granule was synthesized via emulsion polymerization and was characterized by FTIR spectroscopy. The O-carboxymethyl-chitosan was used as emulsifier for the copolymerization of methyl methacrylate and diacetone acrylamide. The resulting copolymer latex showed good compatibility with natural rubber. Morphology and surface roughness of modified natural rubber were measured by SEM and AFM. The tensile strength of natural rubber film reaches the maximum when the amount of additive was about 4%. Glass transition temperature and aging resistance were elevated. Protein spillage dropped in ca. 5 times, which could meet the minimum of the allergy protein.

Discovering novel chemical reactions is important for bioanalysis. Herein, we report a tactic for bio-thiol sensing and protein labeling agent design by the installation of a sulfoxide group onto the skeleton of various fluorophores, and powerfully validate its abilities, which may shed light on the development of specific protein tags to give insight into their biological functions.

A ratiometric fluorescent probe of methionine sulfoxide reductase, Msr-Ratio, was disclosed for monitoring the enzyme activity in vitro and in live cells. The probe displayed favorable properties such as a nearly 400-fold fluorescence change, fast response rate (

A novel ratiometric fluorescent probe was designed and synthesized for detection of bisulfite, via pyrene as an electron donor (D) and 4, 5-dibromothiophene as an electron acceptor (A). It had good selectivity, sensitivity and short response time. The fluorescence intensity ratio at 420 nm and 530 nm (I420/I530) displayed a good linear relationship with the concentration of HSO3− in the range of 0–35 μM, and the detection limit was 0.77 μM. The possible recognition mechanism of probe and HSO3− was illustrated by NMR, HRMS and computational analysis. Notably, the probe was successfully applied for imaging HSO3− in A549 cells, Caenorhabditis elegans and zebrafish, which indicated that this probe had great potential for HSO3− detection in vivo.

Due to the prominent photochemical and photophysical properties, the benzofurazan (NBD) fluorophore is a popular platform for constructing fluorescencet sensors. We reported herein a strategy to tune the fluorescence of NBD by modulating the push-pull pairs on the benzene ring, and obtained two novel fluorescent probes, MeS-DMAB and EtS-DMAB, which can selectively detect hypochlorous acid (HOCl) over other reactive oxygen species in aqueous solution with a large stokes shift (∼170 nm). The synthesis and optical properties of these two probes were described. The reaction products of HOCl with MeS-DMAB were isolated and characterized. It turns out that oxidation of the thioether to the corresponding sulfoxide accounts for the turn-on fluorescence. Finally, the probe EtS-DMAB was successfully applied to image exogenous and endogenous HOCl in live cells.

In this work, three anthraquione-based derivatives containing different heteroatoms (N, O or S) were designed, synthesized and characterized. The red fluorescence of compound AQ-NS was selectively quenched by Cu2+, and was exclusively recovered by the subsequent addition of S2−. Quenching and recovering the fluorescence accompanies with an obvious color change that could be easily observed by naked eyes. Various experiments demonstrated that the probe binding Cu2+ in a 1:1 ratio. In addition, the recyclability and reusability of AQ-NS towards Cu2+ and S2− was evaluated, and the probe shows robust response without significant loss of signals after several cycles of repeated addition of Cu2+ and S2−. Our results demonstrate that the probe AQ-NS can be used for detection of Cu2+ and S2− with high sensitivity and selectivity.

A coarse-grained model-based molecular dynamics simulation was employed to investigate the mechanical properties of NR-graft-rigid-polymer/rigid-polymer systems (N30-g-(R3)6/R10). An external factor (the strain rate) as well as internal factors such as the nonbonding interaction strength, the proportion of rigid polymers, and architecture parameters (the length and number of graft chains in a molecule) were examined for their effect on the tensional behavior of N30-g-(R3)6/R10 systems. Simulation results show that a higher strain rate can promote the enhancement of mechanical performance, such as a higher modulus or yield stress. Moreover, the stress and modulus increase with an increase of the nonbonding interaction strength within rigid polymers or of the rigid polymer proportion in the systems. However, the increasing stress was found to reach a limit with a continuously increasing rigid polymer proportion. On increasing the number of graft chains in a molecule, the stress increases at small strains. However, at large strains, the evident increase in stress was found in systems in which a graft molecule has longer graft chains. In addition, our research shows that N30-g-(R3)6/R10 blends exhibit improved mechanical properties and better compatibilities relative to N30/R10, which is consistent with the experimental results. Lastly, comparisons with experimental observations were also made to ensure the rationality of the simulation results. Overall, bond stretching, bond orientation, and nonbonding interactions were found to be crucial in governing the mechanical properties of the N30-g-(R3)6/R10 systems. These findings may provide important information for further experimental and simulation studies of NR hybrid materials.

We designed and synthesized a new fluorescent probe for detecting pH and HSO3− using pyrene as an electron donor (D) and pyridine as an electron acceptor (A). The fluorescent probe for sensing pH and HSO3− could distinguish these by their spectral properties in different media. pH titrations indicated that the probe displayed a ratiometric emission (pH 7.10–1.36) with a pKa of 4.26, responded linearly to minor pH fluctuations within the acidic pH range of 3.00–5.50 in CH3CN/H2O (1/3, v/v), and exhibited a remarkable emission enhancement (pH 7.10–13.09) with a pKa of 10.91 and a linear response in the extremely alkaline pH range of 9.75–11.35 in CH3CN/H2O (1/19, v/v). Interestingly, the probe also responded to HSO3− with an obvious turn-off fluorescence signal in PBS buffer (pH = 5.00, 1.5% DMSO). This could be attributed to the Michael addition of HSO3− to the α,β-unsaturated ketone, which resulted in breaking of the conjugation. The detection limit (LOD) of the probe for HSO3− based on the definition by IUPAC was calculated to be 1.9 nM. Furthermore, the probe was employed successfully for the imaging of pH and HSO3− in live cells, which indicated that the probe was a suitable indicator for imaging the distribution of pH or HSO3− and tracking their changes.

Methionine sulfoxide reductase (Msr) enzymes have multiple functions such as antioxidant defense and protein repair, and play an important role in regulating cellular redox homeostasis. However, the investigation of the enzymes’ function under physiological/pathological conditions is challenging as there are only limited probes available. In this work, we employed the trifluoromethyl coumarin as a fluorophore and the intramolecular charge transfer sensing mechanism to design a turn-on fluorescent probe, Msr-TFMCM. The methylsulfoxide group in Msr-TFMCM is specifically reduced by Msrs, giving a >50-fold increase of the emission intensity. The practical applications of the probe were demonstrated by imaging the enzymes’ activity in live cells. Our results indicated that Msr-TFMCM could be used for specific monitoring Msrs activity.

Nanoparticles including starch-graft-methylmethacrylate, starch-graft-(methylmethacrylate/methyl acrylate), starch-graft-(methyl methacrylate/butyl methacrylate) were synthesized via emulsifier-free emulsion polymerization and were blended with natural rubber latex at various mass ratios. Chemical structure of graft copolymers was confirmed by Fourier transform infrared. Transmission electron microscopy demonstrated the core-shell structures of the nanoparticles distributed uniformly around the natural rubble particles. The tensile strength of blend films was significantly enhanced by addition of graft copolymers. Besides, scanning electron microscopy and atomic force microscopy showed the blend film had smooth surface.

Achieving tailorable gated adsorption by tuning the dynamic behavior of a host porous material is of great interest because of its practical application in gas adsorption and separation. Here we devise a unique cation-exchange approach to tune the dynamic behavior of a flexible anionic framework, [Zn2(bptc)(datrz)]− (denoted as MAC-6, where H4bptc = [1,1′-biphenyl]-3,3′,5,5′-tetracarboxylic acid and Hdatrz = 3,5-diamine-1H-1,2,4-triazole), so as to realize the tailorable gated adsorption. The CO2 adsorption amount at 273 K can be enhanced by exchanging the counterion of protonated dimethylamine (HDMA+) with tetraethylammonium (TEA+), tetrabutylammonium (TBA+), and tetramethylammonium (TMA+), where the adsorption behavior is transferred from nongated to gated adsorption. Interestingly, the Pgo for gate-opening adsorption can be further tuned from 442 to 331 mmHg by simply adjusting the ratio of HDMA+ and TMA+. The origin of this unique tunable property, as revealed by X-ray diffraction experiments and stru...

Systematic comparisons among the oxazinone, quinazoline, and difluoroboron series on optical absorption and fluorescence emission properties have been made. Weaker electron donor–acceptor (D–A) pairs in both the oxazinone and quinazoline series bring about the slight red shifts of absorption spectra, whereas they significantly promote the fluorescence intensities of the oxazinone series but bathochromically shift the maximum emission wavelengths of the quinazoline series. Intrinsically, the charge-transfer (CT) modes govern the electron excitation/de-excitation processes in both the oxazinone and quinazoline series, but with respective different CT features, i.e., the interfragment CT mode for the oxazinone series versus the intrafragment CT mode for the quinazoline series. In the difluoroboron series, Oxa-Cl-OCH3-BF2 undergoes a change of transition mode from the local excitation to the CT de-excitation, whereas a large variation of CT compositions can be observed in Qui-Cl-OCH3-BF2. Experimentally, Oxa-...

Denaturing anion exchange HPLC simplifies the chromatographic profiles of self-complementary sequences such as d(CG)6, d(CG)6 with locked nucleic acid modifications, d(AT)15, and polymerase chain reaction mixtures. These chromatographic conditions use eluents containing up to 4 M urea at pH 12.4, and lead to the abolishment of secondary structures and meaningful chromatographic patterns of self-complementary sequences. Similarly, PCR template, FAM-labelled primer and FAM-labelled PCR products were resolved, making interpretation of PCR reaction products possible.

A general strategy for designing probes of methionine sulfoxide reductases was reported and a first turn on probe was disclosed., Oxidation of methionine residues to methionine sulfoxide (MetSO) may cause changes in protein structure and function, and may eventually lead to cell damage. Methionine sulfoxide reductases (Msrs) are the only known enzymes that catalyze the reduction of MetSO back to methionine by taking reducing equivalents from the thioredoxin system, and thus protect cells from oxidative damage. Nonetheless, a lack of convenient assays for the enzymes hampers the exploration of their functions. We report the discovery of Msr-blue, the first turn-on fluorescent probe for Msr with a >100-fold fluorescence increment from screening a rationally-designed small library. Intensive studies demonstrated the specific reduction of Msr-blue by the enzymes. Msr-blue is ready to determine Msr activity in biological samples and live cells. Importantly, we disclosed a decline of Msr activity in a Parkinson's model, thus providing a mechanistic linkage between the loss of function of Msrs and the development of neurodegeneration. The strategy for the discovery of Msr-blue would also provide guidance for developing novel probes with longer excitation/emission wavelengths and specific probes for Msr isoforms.

A two-photon fluorescent probe FNTR for nitroreductase was synthesized by using 9,9-dimethyl-2-acetyl-fluoren-7-methylamino (1) as a two-photon fluorophore and a p-nitrobenzyl carbamate group as a recognition domain for nitroreductase (NTR). The probe and the fluorophore were tested under one- and two-photon modes respectively. After reacting with nitroreductase, FNTR had a 130-fold fluorescence enhancement at 563 nm in 10 min and the maximal two-photon action cross-section value was detected as 66 GM at 750 nm. The probe showed a high sensitivity with a detection limit as low as 23.67 ng ml−1, high selectivity, low cytotoxicity and good photostability. In the presence of reduced nicotinamide adenine dinucleotide (NADH), endogenous NTR was detected in living cells, tissues and zebrafish. Cobalt chloride was used to induce chemical hypoxia to produce NTR, which generated enhanced fluorescence in cells and tumor tissues. Finally, two-photon fluorescence imaging of NTR was achieved in zebrafish at a penetration depth of up to 200 μm.

Calcium phosphate cements (CPCs) are a new generation of bone repair materials with good biocompatibility for various stem cells. The minipig is a recommended large animal model for bone engineering research. This study aimed to evaluate the feasibility of utilizing CPC scaffolds for the adhesion, proliferation, and osteogenic differentiation of minipig's bone marrow mesenchymal stem cells (pBMSCs). Passage 3 pBMSCs were seeded on the CPC scaffold and cultured with osteogenic culture medium (osteogenic group) or normal medium (control group). The density of viable cells increased in both groups, and pBMSCs firmly attached and spread well on the CPC scaffold. The alkaline phosphatase (ALP) activity in the osteogenic group had significantly increased on day 7 (D7) and peaked on D14. qRT-PCR revealed that mRNA levels of ALP and three osteogenic marker genes were significantly higher on D4, D7, and D14 in the osteogenic group. Alizarin Red S staining showed a significantly higher degree of bone mineralization from D7, D14 to D21 in the osteogenic group. These results indicated that pBMSCs can attach, proliferate well on CPC scaffold, and be successfully induced to differentiate into osteogenic cells. Our findings may be helpful for bone tissue engineering and the studies of bone regeneration.

A new type of prototypical biphotochromic switches combining spirooxazine and fulgide has been synthesized, and their nonlinear optical (NLO) responses have been theoretically studied on the basis of density functional theory (DFT). Our DFT calculations show that the introduction of a fulgide fragment (E and C) into the spirooxazine host can largely enhance the static second- and third-order NLO responses. Moreover, the photoisomerization of spirooxazine derivatives (SO-E and SO-C) brings forth a pronounced change in the geometry accompanied by the formation of a larger π-conjugated system, and thus the corresponding merocyanine derivatives (PMC-E and PMC-C) obtain ∼3.5-times enhancement of static second- and third-order NLO responses. Nevertheless, the difference in NLO responses between the E-form series (SO-E and PMC-E) and the C-form series (SO-C and PMC-C), respectively, is not substantial, which means the fulgide fragment in the prototypical biphotochromic system does not considerably differentiate ...

A novel cuprous coordination polymer built of [Cu4ICl] cluster and 4-(1,2,4-triazol-4-yl)phenylphosphonate acid (H2ptz) ligand has been hydrothermally synthesized, in which the CuI is in-situ generated by the reduction reaction from CuII precursors. This compound shows a green fluorescent emission with a maximum peak at 510 nm under N2 flow in solid state, which can be turned off by 21 % O2 flow in minutes. Interestingly, it can be turned on again by switching to N2 flow. A possible mechanism has also been proposed.

Hydrothermal reaction of NiCl2 and H2ptz ligand leads to the formation of a two-dimensional Ni(II) coordination polymer, named as [Ni(Hptz)(μ2-Cl)]·2H2O (1, H2ptz = 4-(1,2,4-triazol-4-yl)phenylphosphonate acid), which contains 1D Ni(II) chain structure with a Ni⋯Ni distance of 3.704 A, and shows a (3,6)-connected net with a Schlafli symbol of (3.62)2(34.42.84.95). Magnetic study reveals a ferromagnetic coupling mediated in the chain structure with a fitted J value of 5.0 K. Furthermore, theoretical calculation suggests that the exchange path of Ni–Cl–Ni with spin orbit of dxz–pz–dxz contributes mainly to the ferromagnetic coupling.

TDDFT calculations are used to discuss the effects of the exact exchange (Ex) on the evaluation of second hyperpolarizabilities (γyyyy) of streptocyanines (3–9 carbons). The results confirm that TDDFT calculations are reliable on the reproduction of the first excitation energies (E01) compared with experiments (within 0.3 eV deviations). The sum-over-states (SOS) calculations based on TDDFT suggest that the percentages of Ex determines the γyyyy. The nonlinear optical (NLO) active region of streptocyanines is the π-bridge conjugation where the bond length is between 2 and 3 au. Within this area, the higher the percentage of Ex is, the lower the γyyyy is (γyyyy is normally negative for streptocyanines). The γyyyy can be decomposed into T and N contributions according to the three-level SOS method. The decomposition shows that the T term significantly decreases with the increasing percentages of Ex, while N term gradually increases. Therefore, hybrid generalized gradient approximation (hGGA), hybrid meta-generalized gradient approximation (hybrid meta-GGA) and long-range corrected (LRC) functionals tend to overestimate γyyyy. The functional tuning process can improve the results due to the decreasing of ω. This means the deviation of γyyyy do NOT corresponds to the delocalization error (DE). Consequently, the pure GGA, pure meta-GGA, and LRC with small ω can give qualitative correct results.

The structure–properties relationship of heterocyclic polymethines on the all-optical switching processing (AOSP) is studied by CC2 method. In particular, the excitation energies of the first and second excited states (E ge and E ge′ ) and the corresponding ratio (R ee′ = E ge′ /E ge, energy window width) are evaluated. The comparable energy gap between HOMO and HOMO − 1 (π type) and between LUMO and LUMO + 1 (π* type) is the key in keeping R ee′ large. Moreover, only a significant increase of such energy gap can result in the increase in R ee′ because the energy gap is a poor description of excitation energy. The results show that the heavy heteroatoms decrease the E ge and E ge′ as expected compared to light atoms such as carbon. For five-membered heterocyclic polymethines and their derivatives (two heteroatoms in total), the R ee′ is stable around 1.7 reflecting the nature of this system: The additional heteroatoms have little effects on the width of energy window. In the case of six-membered heterocyclic polymethines and their derivatives, the decrease in excitation energy is more effective compared to the former due to the relative large effective length of the end group, which can thus help avoiding the symmetry breaking. The effect of heteroatoms on R ee′ is clear that it helps keeping the energy window open compared to carbon atom. The heavier the heteroatom is, the higher R ee′ value will be when it is on the ortho position. Consequently, at least one heteroatom is necessary on the design of polymethines for AOSP application.

The teaching content of organic synthesis is rigorous and has high standards for students' knowledge application ability, thinking ability and learning ability. Therefore, how to promote the high-efficiency development of organic synthesis classroom teaching activities in colleges and universities has become a problem that needs to be studied by teachers. The author starts from the factors that hinder the development of organic synthesis classrooms in colleges and universities, and through an in-depth analysis of the actual teaching situation, finds a specific way to promote the smooth progress of the reform. Long-term development of career.

This study aimed to systematically evaluate the effect of nursing interventions on reducing dietary sodium intake in patients with chronic heart failure, further to provide insight on the most utilized nursing practices. Only randomized controlled trials on dietary sodium management of nursing interventions were collected from Pubmed, CINAHL, Web of Science, Embase and The Cochrane Library (CENTRAL). Among 515 available studies, a total of 8 ones met the inclusion criteria and were included. The meta-analysis result suggested that nursing interventions could reduce dietary sodium intake in patients with chronic heart failure within 6 months compared with conventional care [SMD (-0.305, 95%CI -0.561, -0.049)]. Considering the sodium levels estimated by the 3-day food record is much lower than those by the 24-hour urinary sodium, it is better to analyze separately to further clarify the effect of nursing interventions. Hence, further meta-analysis results showed that the sodium intake estimated by the 3-day diet record/diary in the experimental group was lower than that in the control group [SMD -0.523, 95%CI (-0.894 to -0.152), P=0.006]. Similarly, the sodium intake in the experimental group was lower than that in the control group by 24-hour urine specimen [WMD -364.318, 95% CI (-603.953 to -124.684), P=0.003]. We concluded that nursing interventions can reduce dietary sodium intake in patients with chronic heart failure in the short term. However, the long-term effects are uncertain, and long-term planned randomized controlled trials in heart failure patients are required to further verify the effect in the future.

A novel chemiluminescent probe for detection of cysteine (Cys) from other biothiols has been reported by utilizing the excellent chemiluminescent Schaap’s adamantylidene-dioxetane scaffold. After careful assessment, the probe CL-Cys could detect Cys with high sensitivity and total light photons increased by 28-fold after the probe was treated with Cys, with the detection limit of 7.5 × 10–8 M. Finally, CL-Cys was further utilized for the chemiluminescent imaging of endogenous Cys in a living mouse. In general, this probe has a remarkable ability to detect Cys, which provides a valuable method for interrogation of the Cys roles in more biological and pathological processes.

Hypoxia is a common characteristic of solid tumors, which is caused by the imbalance of oxygen supply and consumption. As the expression level of nitroreductase (NTR) increases in hypoxic solid tumors, NTR is one of the common biomarkers of hypoxia and widely used to evaluate the degree of tumor hypoxia. In this study, we designed and synthesized a highly water-soluble chemiluminescent probe, CL-NTR, for the detection of NTR activity in hypoxic tumors. It was found that the probe could be used to detect NTR with high sensitivity, and the total light photons increased tremendously with 6000-fold after the probe was treated with NTR. The chemiluminescence total light photons emission was directly proportional to the concentration of nitroreductase in the range of 3-55 ng/mL, with a detection limit of 0.947 ng/mL. Finally, the probe was successfully used to evaluate NTR activity in living mice by chemiluminescent imaging. In general, this probe has a remarkable response to NTR, which provides a promising method for the determination of NTR activity in vivo.

A ratiometric fluorescence pH probe 2-(N-ethylcarbazole-3-vinyl)-benzothiazole ( ECBT ) is facilely developed by ethylene bridging of N-ethyl-3-carbazolecarboxaldehyde and benzothiazole, which is a useful fluorescent probe for strongly acidic pH sensing. The pH titration indicates remarkable fluorescence enhancement effect and an emission red-shift of 87 nm with pH decreasing from 7.00 to 1.00. Furthermore, the solution color changes from light blue to orange under a UV lamp illumination. A p K a value of 1.62 and a good linearity in the pH range of 1.23–2.10 indicate that the probe can be used in quantitative fluorescence imaging under strongly acidic condition. In addition, ECBT exhibits high selectivity and sensitivity, good photostability and excellent reversibility for pH sensing. The probe is further applied successfully to imaging extreme acidity in Escherichia coli cells without influence of autofluorescence in biological systems.

Metal–organic frameworks with tunable functional groups like solid-solution have received considerable interest. In this paper, a crs-type structure built of [Zn3(OH)(dmtrz)3] triazolate-trinuclear and [Zn2(COO)4] paddlewheel units, linked by 3,5-dimethyl-1,2,4-triazolate (dmtrz) and isophthalate (ipa) ligands (named as MAC-4-A), has been used as a prototype framework. Four types of functional groups (B: 5-hydroxyisophthalate, C: 5-aminoisophthalate, D: 5-ethoxyisophthalate, and E: 5-acetamidoisophthalate) have been integrated into the framework, giving isostructures of MAC-4-B to E, respectively. Then, by the solid-solution framework approach, four group samples are prepared, which are MAC-4-AB-x, MAC-4-AC-x, MAC-4-AD-x, and MAC-4-AE-x (x denoted as the ratio of functional ligands in the framework, x = 0.3, 0.5, 0.7), and their CO2 and N2 adsorptions have been studied. Our results revealed that the CO2 capacity is enhanced with the increase of functional groups and then decreases, showing a maximum uptak...

A new type of diacetylene monomer which includes a biphenylcarboxylic acid group as its head group is synthesized. Polymerization was performed after monomer form spherical vesicle by self-assembly in the water. The polydiacetylene displayed completely thermochromic color change in the range of 20–95 °C owing to the presence of strong π – π interaction caused by biphenyl group and hydrogen bonding between head group.

Two metal–organic frameworks containing a geometrically spin-frustrated trinuclear-triangular copper cluster ([Cu3O]) have been successfully isolated, which are {[Cu4.5(μ3-OH)(dmtrz)3(m-bdc)2.5(H2O)2(CH3OH)(DMF)]·DMF·5H2O}n (MAC-8) and {[Cu5(μ3-OH)(dmtrz)3(bdc)3(H2O)4]·3H2O}n (MAC-9) (Hdmtrz = 3,5-dimethyl-1H-1,2,4-triazole, H2m-bdc = 1,3-benzenedicarboxylic acid, H2bdc = 1,4-benzenedicarboxylic acid, DMF = N′,N-dimethylformamide). Magnetic and gas adsorption studies revealed the successful combination of strong antiferromagnetic properties (Jav = −106.6 and −113.7 cm–1 for [Cu3O] in MAC-8 and MAC-9, respectively) and high surface areas (1058 m2/g for MAC-8 and 1242 m2/g for MAC-9) in both of the structures. Further structural studies revealed that the high surface areas could be ascribed to the unique two-dimensional hexagonal pattern of [Cu3(O)] clusters, in which the [Cu3(O)] clusters are connected to each other in an end-end fashion via mononuclear copper ions/paddle-wheel units.

DNA-binding agents have been considered as an established opportunity for the development of anticancer drugs and DNA fluorescence probes. This work reported the synthesis of two novel carbazole derivatives (1 and 2) and investigated their DNA binding properties, living cell image, and cytotoxicity. The results demonstrated that both compounds presented the higher binding affinity to G-quadruplex than to duplex DNA by means of UV–Vis absorption titration and fluorescent intercalator displacement. Continuous variation analysis indicated that their binding stoichiometries of the compound/G-quadruplex were near 2 except the compound/bcl-2. Circular dichroism spectra showed that both compounds had no influence on the conformation of G-quadruplexes. Fluorescence titrations indicated that 2 had the potential to be a G-quadruplex selective fluorescent probe, while 1 could be used as a fluorescent probe for duplex DNA. Confocal fluorescence images indicated that both compounds could enter the living HepG2 cells, and 1 mainly located in nucleus whereas 2 mainly distributed in cytoplasm. DNase and RNase digest tests indicated that both compounds could enter into the nucleus and interact with duplex DNA, especially, 2 could interact with RNA and/or G-quadruplex DNA. They also exhibited an obvious antiproliferative activity to HepG2 by using MTT assays, with IC50 values of 2.7 and 9.5 μM for 1 and 2, respectively.

The primary objective of this study is to evaluate the interactions of human serum albumin (HSA) with peimine (PE) and peiminine (PEN) in physiological conditions by fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) spectroscopy, Raman spectroscopy, and molecular modeling. PE and PEN were isolated from Bulbus Fritillariae thunbergii miq. The binding constants Ka and the number of binding sites n were calculated at different temperatures. Enthalpy change (ΔH), entropy change (ΔS), and Gibbs free energy change (ΔG) were also determined. The results suggested that quenching of HSA fluorescence by PE and PEN is a static process. Three-dimensional fluorescence, FT-IR, CD, and Raman spectra showed that the binding of PE and PEN to HSA can induce conformational changes in the latter. Moreover, important differences in binding ability were observed between PE and PEN, and PE showed stronger binding affinity to HSA than PEN.

We report herein that exposure of DNA to microwave irradiation at constant temperature leads to faster strand exchange, as compared with same experiments carried out in a water bath at the same temperature. Furthermore, polymerase chain reactions carried out under microwave irradiation were faster than those in a water bath at the same temperature as well. While the causes of these differences are unclear at this time, this research suggests that microwave irradiation can lead to subtle changes in DNA structural dynamics and functions.

The first fluorescent probe for mammalian thioredoxin reductase (TrxR), TRFS-green, was designed, synthesized, and fully evaluated. The probe features a 1,2-dithiolane scaffold with a quenched naphthalimide fluorophore. TRFS-green displays a green fluorescence off-on change induced by the TrxR-mediated disulfide cleavage and subsequent intramolecular cyclization to liberate the masked naphthalimide fluorophore. It was demonstrated in vitro that TRFS-green manifests high selectivity toward TrxR over other related enzymes and various small molecule thiols as well as biological reducing molecules. HPLC analyses indicated that TRFS-green was exclusively converted to naphthalimide catalyzed by TrxR. The ability in triggering on the fluorescence signal by cellular protein extracts correlates well with the endogenous TrxR activity in different cells. Furthermore, inhibition of TrxR by 2,4-dinitrochlorobenzene or depletion of TrxR by immunoprecipitation remarkably decreases the reduction of TRFS-green by cellular protein extracts. Finally, TRFS-green was successfully applied in imaging TrxR activity in living cells. The fluorescence signal of TRFS-green in living cells was inhibited by pretreating the cells with TrxR inhibitor in a dose-dependent manner, potentiating the development of living cell-based screening assay for identifying TrxR inhibitors. We expect the novel fluorescent probe TRFS-green would facilitate the discovery of TrxR-targeting small molecules for potential therapeutic agents and provide significant advances in understanding the physiological/pathophysiological functions of TrxR in vivo.

The linear and third-order nonlinear optical properties of four polymethine cyanines (PC-1–PC-4) were investigated by UV–visible absorption spectroscopy and degenerate four-wave mixing (DFWM) technique. The second-order hyperpolarizabilities γ of the four chromophores achieve 10−31 esu. The dependence of their third-order optical nonlinearities on the molecular structure was discussed based on density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations. The calculated second-order hyperpolarizabilities γ well-reproduce the experimental trends. The results show that the third-order optical nonlinearities of the chromophores can be drastically enhanced by bulky heteroatom (such as selenium) with low electro-negativity, or extended π-conjugated terminal group.

Diethyl 2,2'-(2-oxo-2-(quinolin-8-ylamino)ethylazanediyl) diacetate (DOQED), an aminoquinoline-based fluorescent probe, was synthesized, and successfully applied in detection of Cu2+ and S2- in an aqueous buffered solution. The emission signal of DOQED was selectively quenched by Cu2+, and was exclusively recovered by subsequent addition of S2-. The formation of a [Cu(DOQED)](2+) complex was confirmed by X-ray crystallography. (C) 2013 Elsevier B.V. All rights reserved.

An optimized and validated spectrofluorimetric method has been developed for the rapid determination of aluminum in absolute ethanol. The method is based on the chelation of aluminum and luteolin which results in a complex exhibiting an intense emission signal. The characterization of Al-luteolin complex was studied using ultraviolet-visible spectrometry, infrared spectrometry, fluorescence and mass spectrometry. The complex stoichiometry ratio of aluminum:luteolin was 1:2. The fluorescence of the complex was monitored at an emission wavelength of 545 nm with excitation at 518 nm. The linear concentration range was 6.5 × 10(-7) to 4.0 × 10(-5) M with a correlation coefficient of r = 0.998. The detection limit was 5.0 × 10(-7) M. The method was appropriately validated and yielded relative standard deviations of

A carboxamidoquinoline-based fluorescent Zn2+ probe 1 containing N/S/S heteroatoms as a receptor was designed and readily synthesized, which was featured by the Zn2+-induced red-shift of emission (45 nm) based on internal charge transfer (ICT) in an aqueous HEPES buffer (pH=7.4). Moreover, spectroscopic studies indicated that the composition of the complex 1-Zn2+ was 1:1, which was also confirmed by X-ray crystallography. In addition, 1H NMR titration experiment suggested that probe 1 transformed from the amide tautomer to imidic acid tautomer after binding with Zn2+. The binding of zinc with 1 was easily reversed by addition of N,N,N′,N′-tetrakis(2-picolyl)ethylenediamine (TPEN) or EDTA. Furthermore, probe 1 was successfully applied to image both exogenous and endogenous zinc in living HeLa cells.

The chemisorption of gaseous HCl molecules in a two-dimensional coordination polymer results in subtle changes in its structure and instigates a drastic modification from antiferro- to ferromagnetic properties.

A novel turn-on type of ultrafast biothiol fluorescent probe, Naph-EA-mal, was designed, synthesized and evaluated. The probe contains a naphthalimide moiety as a fluorophore, a maleimide unit as a thiol acceptor, and 1,2-ethylenediamine as a linker. Naph-EA-mal displays high selectivity and a fast response toward thiols in aqueous solution. The reaction mechanism of the probe with thiols was confirmed by 1H NMR and HRMS. Test strips were fabricated and a sharp color change was observed by the naked-eye. Furthermore, Naph-EA-mal was successfully applied to label protein thiols, image thiols in living cells, quantify thiol content in cells lysate, and determine the reversible protein thiols oxidation in fixed cells.

The authors synthesized struvite crystals in the presence of Proteus mirabilis/urea and by using ammonium carbonate. The products were characterized by scanning electron microscopy and X-ray diffraction. The results showed that the struvite particles produced with bacteria are larger than those formed without bacteria. The formation mechanism of struvite crystals in bacterial solution is explored, indicating that the bacterial biomolecules may act as templates to induce the nucleation, growth, and aggregation of struvite crystals. This study may help to understand the true role of some common bacteria in the stone formation process, and it is also significant for synthesizing inorganic materials.