Orange/far-red hybrid voltage indicators with reduced phototoxicity enable reliable long-term imaging in neurons and cardiomyocytes.

Hybrid voltage indicators (HVIs) are chemogenetic sensors that combines the superior photophysical properties of organic dyes and the genetic targetability of protein sensors to report transient membrane voltage changes. They exhibit boosted sensitivity in excitable cells such as neurons and cardiomyocytes. However, the voltage signals recorded during long-term imaging are severely diminished or distorted due to phototoxicity and photobleaching issues. To capture stable electrophysiological activities over a long time, we employ cyanine dyes conjugated with a cyclooctatetraene (COT) molecule as the fluorescence reporter of HVI. The resulting orange-emitting HVI-COT-Cy3 enables high-fidelity voltage imaging for up to 30 min in cultured primary neurons with a sensitivity of ~ -30% ΔF/F0 per action potential (AP). It also maximally preserves the signal of individual APs in cardiomyocytes. The far-red-emitting HVI-COT-Cy5 allows two-color voltage/calcium imaging with GCaMP6s in neurons and cardiomyocytes for 15 min. We leverage the HVI-COT series with reduced phototoxicity and photobleaching to evaluate the impact of drug candidates on the electrophysiology of excitable cells.

Self-assembled hierarchical Bi12TiO20-graphene nanoarchitectures with excellent simulated sunlight photocatalytic activity.

A series of hierarchical Bi12TiO20-graphene nanoarchitectures (Bi12TiO20-GR) with GR loadings from 1% to 10% are fabricated by a single-step solvothermal treatment technique, and the intimate interfacial contact between flexible GR sheets and flower-like Bi12TiO20 nanocrystals is observed in the Bi12TiO20-GR composites. As a novel composite photocatalyst, Bi12TiO20-GR with GR loading of 2% possesses the highest simulated sunlight photocatalytic activity towards the degradation of two typical organic pollutants, methyl orange (MO) and p-nitrophenol (PNP). Furthermore, the separation and transportation of the photogenerated carriers in the simulated sunlight-irradiating Bi12TiO20-GR system is studied, meanwhile, the active species (hVB(+), O2˙(-) and ˙OH) generated in the Bi12TiO20-GR-photocatalyzed PNP degradation system are identified by free radical and hole scavenging experiments. Based on the experimental and theoretical results, the mechanism and pathway of photocatalytic degradation of PNP in the simulated sunlight-irradiating Bi12TiO20-GR system are proposed.

Morphology-controlled preparation and enhanced simulated sunlight and visible-light photocatalytic activity of Pt/Bi5Nb3O15 heterostructures.

Plate- and octahedron-like Pt/Bi5Nb3O15 heterostructures are controllably prepared by a hydrothermal treatment method combined with photodeposition in the presence of different surfactants, i.e., cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP). The composition, structure, morphology, optical absorption properties, and textural properties of as-prepared Pt/Bi5Nb3O15 are well-characterized, and their simulated sunlight and visible-light photocatalytic activity is evaluated by the degradation of two typical organic pollutants, i.e., methyl orange (MO) and p-nitrophenol (PNP). Special attention is paid to investigate and explain the influence of the morphologies on the photocatalytic activity of the heterostructured Pt/Bi5Nb3O15.

Copper doping and organic sensitization enhance photocatalytic activity of titanium dioxide: Efficient degradation of phenol and tetrabromobisphenol A.

A novel photocatalyst (Cu-TiO2@HQ) had been synthesized by combining Cu-doped TiO2 nanoparticles with 8-Hydroxyquinoline (HQ) via hydrothermal method. The photocatalytic activities of Cu-TiO2@HQ were investigated by using phenol and tetrabromobisphenol A (TBBPA) as target pollutants, respectively. The results indicated that the degradation efficiencies of phenol and TBBPA by Cu-TiO2@HQ were 99.2% (in 30 min) and 99.4% (in 10 min) under visible light irradiation. Both of them were much better than that of pure TiO2 (8.63% in 30 min) and Cu-TiO2 (14.74% in 30 min). When phenol or TBBPA were degraded together with the reduction of Cr (VI), the reaction rate of each pollutant was significantly increased, and the cyclic stability of photocatalyst Cu-TiO2@HQ was greatly improved. Based on the spectroscopic and photoelectric characteristic analysis we found that in the mixture of phenol-Cr (VI) or TBBPA-Cr (VI) both photo-generated electrons and holes can be consumed simultaneously, thus preventing their recombination. The possible degradation products of phenol and TBBPA including its degradation path way were also analyzed by high resolution liquid chromatography-mass spectrometry-mass spectrometry.

catena-Poly[[diaqua-zinc(II)]-µ-4,4'-(methyl-enedioxy)-dibenzoato].

In the title complex, [Zn(C(15)H(10)O(6))(H(2)O)(2)](n), the Zn(II) atom is located on a twofold rotation axis and exhibits a distorted tetrahedral coordination environment defined by two O atoms from two 4,4'-(methyl-enedioxy)-dibenzoate ligands and two O atoms from two coordinated water mol-ecules. In the crystal structure, mol-ecules are linked into a three-dimensional framework by O-H⋯O hydrogen bonds and C-H⋯π inter-actions.

Low-cost and environment-friendly synthesis of carbon nanorods assembled hierarchical meso-macroporous carbons networks aerogels from natural apples for the electrochemical determination of ascorbic acid and hydrogen peroxide.

In this work, the low-cost carbon nanorods assembled hierarchical meso-macroporous carbons networks aerogels (CNs-HMCNAs) was environment-friendly synthesized from a cheap and abundant biomass of apples (Malus pumila Mill) for the first time. The biomass of apples derived CNs-HMCNAs exhibited the unique hierarchical meso-macroporous structure with large specific surface area and high density of edge defective sites. At the CNs-HMCNAs modified GCE (CNs-HMCNAs/GCE), the electron transfer between the glassy carbon electrode (GCE) and the ascorbic acid (AA) (or hydrogen peroxide (H2O2)) was effectively enhanced, and thus induced a low overvoltage for AA electrooxidation (or H2O2 electroreduction). As an electrochemical AA (or H2O2) sensor, the CNs-HMCNAs/GCE exhibited wider linear range, lower detection limit, higher sensitivity and stability than GCE and the carbon nanotubes modified GCE (CNTs/GCE). In particular, the CNs-HMCNAs/GCE showed great potential feasibility in the practical determination of AA (in AA injection, Vitamin C tablet and kiwi juice) or H2O2 (in human urine, milk and beer).

Capillary electrophoresis-integrated immobilized enzyme microreactor utilizing single-step in-situ penicillinase-mediated alginate hydrogelation: Application for enzyme assays of penicillinase.

Rapid, low-cost and efficient assays for penicillinase activity and inhibition are of vital importance for therapeutics and diagnostics of bacterial resistance to antibiotics. Herein we report a novel approach for on-line enzyme assays for penicillinase utilizing capillary electrophoresis-integrated immobilized enzyme reactors (CE-IMERs). The CE-IMERs are fabricated based on penicillinase-mediated alginate hydrogelation, allowing single-step in-situ encapsulation of enzymes without any additional manipulation process. We show that the fabricated CE-IMERs have high enzyme loading capacity with approximately 61.8% of the original penicillinase in the sol mixture being encapsulated in the "egg-box" hydrogel matrix. Excellent intraday and interday stability and batch-to-batch reproducibility are proved, indicating the reliability of our method for accurate on-line enzyme assays for penicillinase. Enzymatic activities and inhibition of immobilized penicillinase are analyzed, the results of which are in good agreement with those using free enzymes. The proposed method is successfully used for determination of penicillin in pork samples, indicating the potential applications for analysis of complicated real samples.

Enhanced photocatalytic conversion and selectivity of nitrate reduction to nitrogen over AgCl/TiO2 nanotubes.

TiO2 nanotubes (TNTs) and AgCl/TiO2 nanotubes (AgCl/TNTs) were synthesized by a hydrothermal method and used in the reduction of nitrate with formic acid as a hole scavenger. As-synthesized photocatalysts were well characterized by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), N2 adsorption-desorption and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). 5 wt% AgCl/TNTs showed excellent performance in the reduction of nitrate (94.5% conversion of nitrate and 92.9% selectivity to N2, respectively) under UV light (365 nm) irradiation for 30 min. After four reduction cycles of nitrate the 5 wt% AgCl/TNTs also exhibited steady photoactivity. The enhanced photoreductive ability and stability attributed to the nanotube structures provided a higher specific surface area and more active sites. For the combination of AgCl and TNTs, the SPR effect of Ag0 formed by UV light irradiation improved the separation of electron-hole pairs which was proved by the electrochemistry impedance spectra. The effects of AgCl content, hole scavengers, and concentration of formic acid were systematically investigated. Based on the above results a mechanism was proposed. This work provides a novel method for high conversion and selectivity of nitrate reduction to nitrogen by photocatalytic technology.

Simulated sunlight photocatalytic degradation of aqueous p-nitrophenol and bisphenol A in a Pt/BiOBr film-coated quartz fiber photoreactor.

Pt/BiOBr film-coated quartz fiber bundles were prepared by dip-coating combined with photodeposition, and their phase and chemical structures, electronic and optical properties, textural properties as well as morphologies were well-characterized. The simulated sunlight photocatalytic performance including activity and stability of the as-prepared Pt/BiOBr film was evaluated in a self-made quartz fiber photoreactor by selecting two typical light-insensitive organic pollutants, p-nitrophenol (PNP) and bisphenol A (BPA), as the target compounds. Since the quartz fiber bundles served as both the support for Pt/BiOBr films and the medium of light propagation, Pt/BiOBr film-coated quartz fiber bundles exhibited excellent photocatalytic activity due to their enhanced light harvesting ability. In addition, the enhanced photocatalytic activity of the Pt/BiOBr film is explained based on the results of photoelectrochemistry and free radical and hole scavenging experiments.

[Library search of UV spectra of organic environmental pollutants by temperature-constrained cascade-correlation networks].

A temperature-constrained cascade-correlation network (TCCCN) was used to identify ultraviolet (UV) spectra of organic environmental pollutants. Library search for UV spectra is more difficult than that for infrared (IR) spectra, because the UV spectra overlap more severely than IR spectra. Besides, drift and noise in the measurement will have significant effect on UV library spectra search. Therefore, neural networks with fuzzy output should be a better alternative for the library search. The TCCCN is different from the commonly used BP networks in architecture. The processing units in the TCCCN are connected in a cascade mode, and a temperature constraint is introduced. Therefore, the TCCCN can reduce overtraining and fast training speed. TCCCN was used for library search of UV spectra in the present work and the effects of network parameters and noise were investigated. Results showed that better results were obtained with the TCCCN than with conventional correlation method.

Sequential micellar electrokinetic chromatography analysis of racemization reaction of alanine enantiomers.

A novel method for online monitoring racemization reaction of alanine (Ala) enantiomers was developed, by combining sequential sample injection and micellar electrokinetic chromatography (MEKC) technique. Various conditions were investigated to optimize the sequential injection, Ala derivatization and MEKC chiral separation of d-/l-Ala. High reproducibility of the sequential MEKC analysis was demonstrated by analyzing the standard Ala samples, with relative standard deviation values (n=20) of 1.35%, 1.98%, and 1.09% for peak height, peak area and migration time, respectively. Ala racemization was automatically monitored every 40s from the beginning to the end of the reaction, by simultaneous detection of the consumption of the substrate enantiomer and the formation of the product enantiomer. The Michaelis constants of the racemization reaction were obtained by the sequential MEKC method, and were in good agreement with those obtained by traditional off-line enzyme assay. Our study indicated that the present sequential MEKC method can perform fast, efficient, accurate and reproducible analysis of racemization reaction of amino acids, which is of great importance for the determination of the activity of racemase and thus understanding its metabolic functions.

Fabrication of Z-scheme plasmonic photocatalyst Ag@AgBr/g-C3N4 with enhanced visible-light photocatalytic activity.

A series of Ag@AgBr grafted graphitic carbon nitride (Ag@AgBr/g-C3N4) plasmonic photocatalysts are fabricated through photoreducing AgBr/g-C3N4 hybrids prepared by deposition-precipitation method. The phase and chemical structures, electronic and optical properties as well as morphologies of Ag@AgBr/g-C3N4 heterostructures are well-characterized. Subsequently, the photocatalytic activity of Ag@AgBr/g-C3N4 is evaluated by the degradation of methyl orange (MO) and rhodamin B (RB) under visible-light irradiation. The enhanced photocatalytic activity of Ag@AgBr/g-C3N4 compared with g-C3N4 and Ag@AgBr is obtained and explained in terms of the efficient visible-light utilization efficiency as well as the construction of Z-scheme, which keeps photogenerated electrons and holes with high reduction and oxidation capability, evidenced by photoelectrochemical tests and free radical and hole scavenging experiments. Based on the intermediates identified in the reaction system, the photocatalytic degradation pathway of MO is put forward.

Preparation and enhanced visible-light photocatalytic activity of graphitic carbon nitride/bismuth niobate heterojunctions.

A series of graphitic carbon nitride/bismuth niobate (g-C3N4/Bi5Nb3O15) heterojunctions with g-C3N4 doping level of 10-90 wt% were prepared by a facile milling-heat treatment method. The phase and chemical structures, surface compositions, electronic and optical properties as well as morphologies of the prepared g-C3N4/Bi5Nb3O15 were well-characterized. Subsequently, the photocatalytic activity and stability of g-C3N4/Bi5Nb3O15 were evaluated by the degradation of aqueous methyl orange (MO) and 4-chlorophenol (4-CP) under the visible-light irradiation. At suitable g-C3N4 doping levels, g-C3N4/Bi5Nb3O15 exhibited enhanced visible-light photocatalytic activity compared with pure g-C3N4 or Bi5Nb3O15. This excellent photocatalytic activity was revealed in terms of the extension of visible-light response and efficient separation and transportation of the photogenerated electrons and holes due to coupling of g-C3N4 and Bi5Nb3O15. Additionally, the active species yielded in the pure g-C3N4- and g-C3N4/Bi5Nb3O15-catalyzed 4-CP photodegradation systems were investigated by the free radical and hole scavenging experiments.

Efficient degradation of tetrabromobisphenol A by heterostructured Ag/Bi5Nb3O15 material under the simulated sunlight irradiation.

Heterostructured metallic silver-layered bismuth niobate two-component system (Ag/Bi(5)Nb(3)O(15)) was developed for the first time by a mild hydrothermal method combined with photodeposition. The Ag/Bi(5)Nb(3)O(15) exhibited single-crystalline orthorhombic structure with small particle size (50-200 nm) and octahedral as well as sheet-like shape; additionally, it possessed photoresponse in both UV and visible region. As a novel alternative photocatalysts to TiO(2), the photocatalytic activity of the Ag/Bi(5)Nb(3)O(15) was evaluated by the degradation of tetrabromobisphenol A, a member from the family of the brominated flame retardant, under solar simulating Xe lamp irradiation, and enhanced photocatalytic activity in compared to Bi(5)Nb(3)O(15) itself and Degussa P25 was obtained.

Simulated sunlight photodegradation of aqueous phthalate esters catalyzed by the polyoxotungstate/titania nanocomposite.

A series of porous polyoxotungstate/titania nanocomposites (PW(12)/TiO(2)) with particle size lower than 10nm and BET surface area of ca. 200 m(2)g(-1) was prepared by sol-gel chemistry combined with solvothermal treatment. The composites were successfully applied to the degradation of aqueous phthalate esters (PAEs) including di-n-butyl phthalate (DBP), diethyl phthalate (DEP), and dimethyl phthalate (DMP) under the simulated sunlight irradiation (lambda=320-680 nm) for the first time, and the conversion of DBP, DEP, and DMP reached to 98%, 84%, and 80%, respectively, after the simulated sunlight irradiation the suspension including PAE (5 mg L(-1), 100 mL) and PW(12)/TiO(2)-19.8 (100 mg) for 90 min. In addition, nearly total mineralization of DBP and DEP was realized by further increasing light irradiation time to 12h. Based on the intermediates identified in the reaction system, the photocatalytic degradation pathway of PAEs was put forward.

Mixed phase titania nanocomposite codoped with metallic silver and vanadium oxide: new efficient photocatalyst for dye degradation.

Titania nanocomposite codoped with metallic silver and vanadium oxide was prepared by a one-step sol-gel-solvothermal method in the presence of a triblock copolymer surfactant (P123). The resulting Ag/V-TiO(2) three-component junction system exhibited an anatase/rutile (weight ratio of 73.8:26.2) mixed phase structure, narrower band gap (2.25 eV), and extremely small particle sizes (ca. 12 nm) with metallic Ag particles well distributed on the surface of the composite. The Ag/V-TiO(2) nanocomposite was used as the visible- and UV-light-driven photocatalyst to degrade dyes rhodamine B (RB) and coomassie brilliant blue G-250 (CBB) in an aqueous solution. At 1.8% Ag and 4.9% V doping, the Ag/V-TiO(2) system exhibited the highest visible- as well as UV-light photocatalytic activity; additionally, the activity of the three-component system exceeded that of Degussa P25, pure TiO(2), single-doped TiO(2) system (Ag/TiO(2) or V-TiO(2)) as well as P123-free-Ag/V-TiO(2) codoped system. The reasons for this enhanced photocatalytic activity were revealed.