Tetrabutylammonium Tribromide-Induced Synthesis of Silver Nanowires with Ultrahigh Aspect Ratio for a Flexible Transparent Film.

Silver nanowires (AgNWs) have gained significant attention from researchers as a promising material for producing flexible transparent conductive films, which can be utilized in touch and display screens. Thereinto, the ultrahigh aspect ratio AgNW network can theoretically decrease the contact resistance effectively while still retaining considerable mechanical and optical properties. However, fabrication of high-quality AgNWs with a fine diameter and high aspect ratio is still challenging. Herein, a simple and robust approach to synthesize ultrahigh aspect ratio AgNWs is presented. This study successfully fabricated AgNWs with the highest aspect ratio up to ∼4000 and an average length of ∼72 µm by utilizing tetrabutylammonium tribromide as an auxiliary additive. The manifestation of tetrabutylammonium tribromide was proven to be beneficial for the generation of silver seeds and the expansion of AgNWs. The obtained AgNWs were utilized to create a transparent conductive film that showed low sheet resistance of 22.4 Ω/sq and high transmittance and low haze of 87.71 and 4.15%, respectively. The transmittance and haze of the vacant poly(ethylene terephthalate) support were 90.13 and 2.05%, thereby offering great potential for application in flexible transparent electrodes.

Preparation of flower-like molybdenum disulfide for solid-phase extraction of N-nitrosoamines in environmental water samples.

In this paper, a flower-like molybdenum disulfide material was prepared by hydrothermal method and was first used as adsorbents in the solid-phase extraction process for enriching N-nitrosoamines. Molybdenum disulfide exhibited three-dimensional petal-like microspheres with about 500 nm in diameter. The relevant analyte extraction and elution parameters (sample volumes, solution pH, washing solvents, elution solvents, and elution volumes) were optimized to improve the solid-phase extraction efficiency. The solid-phase extraction process coupled with high-performance liquid chromatography-tandem mass spectrometry for determining N-nitrosoamines in environmental water samples was established. The limits of detection were in the range of 0.01-0.05 ng/mL. The satisfactory recoveries (68.9-106.1%) were obtained at three different spiked concentrations (2, 5, and 8 ng/mL) in water samples, and the relative standard deviations were between 1.96 and 8.38%. This proposed method not only showed high sensitivity and good reusability but also provided a new adsorbent for enriching trace N-nitrosoamines in environmental water samples.

The bioequivalence of a single dose of a generic solifenacin succinate tablet or Vesicare in fasting or postprandial healthy Chinese adults.

OBJECTIVE: The present study evaluated the bioequivalence of the test preparation (5 mg generic solifenacin succinate tablet, produced by Jiangsu Deyuan Pharmaceutical Co., Ltd.) or the reference preparation (5 mg solifenacin succinate tablets with the trade name Vesicare, produced by Astellas Pharma Europe B.V.) in either fasting or postprandial states in healthy Chinese subjects. MATERIALS AND METHODS: The present study was designed as an open-label, randomized, single-center, single-dose, dual-cycle, dual-crossover, fasting/postprandial study. 56 healthy Chinese subjects (28 each in the fasting and postprandial groups) were enrolled. WinNolin software (version 7.0 or above) was used to calculate the pharmacokinetic parameters. RESULTS: In the fasting and postprandial group, pharmacokinetic analysis and bioequivalence analysis were carried out based on the blood concentration-time data. The 90% confidence interval of the geometric mean ratio of Cmax, AUC0-t, and AUC0-∞ of the test preparation and the reference preparation were both within the acceptance range of 80.00 - 125.00%. CONCLUSION: A single administration of a 5-mg tablet of either the test preparation, generic solifenacin succinate, or the reference preparation, solifenacin succinate with the brand-name Vesicare, was safe and bioequivalent in healthy Chinese subjects in either fasting or postprandial states according to the criteria of bioequivalence of the State Drug Administration of China.

Bioequivalence of daclatasvir hydrochloride tablets in healthy Chinese subjects.

OBJECTIVE: The aim of the present study was to evaluate the bioequivalence and safety of two types of daclatasvir hydrochloride tablets administered to healthy Chinese subjects under fasting and postprandial conditions. MATERIALS AND METHODS: A total of 72 healthy Chinese subjects were randomly divided into two groups: the fasting group (n = 36) and the postprandial group (n = 36). A dose of 60 mg of both the test and reference preparations of the daclatasvir hydrochloride tablets was taken orally under fasting and postprandial conditions. RESULTS: The main plasma pharmacokinetic parameters of the test and reference preparations in the fasting group were as follows: T1/2 was 9.82 ± 1.00 and 9.67 ± 0.99 hours, respectively; tmax was 1.00 hour in both; Cmax was 1,528.25 ± 428.80 and 1,504.25 ± 414.50 ng/mL-1, respectively; AUC0-t was 14,553.04 ± 4,013.26 and 14,391.97 ± 4,078.18 h/ng/mL-1, respectively; the AUC0-∞ was 14,660.80 ± 4,018.37 and 14,494.85 ± 4,095.57 ng/mL-1, respectively. Meanwhile, the main plasma pharmacokinetic parameters of the test and reference preparations in the postprandial group were as follows: T1/2 was 10.18 ± 1.38 and 10.18 ± 1.69 hours, respectively; tmax was 2.00 and 1.75 hours, respectively; Cmax was 974.92 ± 248.50 and 981.44 ± 237.11 ng/mL-1, respectively; AUC0-t was 9,597.00 ± 3,094.28 and 9,982.83 ± 3,512.07 h/ng/mL-1, respectively; AUC0-∞ was 9,712.92 ± 3,130.43 and 10,113.97 ± 3,593.47 ng/mL-1, respectively. CONCLUSION: Both types of daclatasvir hydrochloride tablets demonstrated good safety levels in healthy Chinese subjects under both fasting and postprandial conditions. Moreover, the two preparations were bioequivalent.

Synthesis of molecularly imprinted polymer adsorbents for solid-phase extraction of strobilurin fungicides from agricultural products.

Molecularly imprinted polymers for strobilurin fungicides were prepared by precipitation polymerization employing azoxystrobin as template molecular together with methacrylic acid monomer and trimethylolpropane triacrylate cross-linker. Morphological characterization showed molecularly imprinted polymers were uniform spherical particles with about 0.2 µm in diameter, while the morphologies of nonimprinted polymers were irregular bulk. The equilibrium binding and selective experiments proved that molecularly imprinted polymers possessed a higher affinity toward four fungicides compared to nonimprinted polymers and heterogeneous binding sites were found in the molecularly imprinted polymers. Molecularly imprinted solid-phase extraction conditions, including sample loading solvents, selective washing, and elution solvents, were carefully optimized. The developed method showed good recoveries (70.0-114.0%) with relative standard deviations in range of 1.0-9.8% (n  = â€¯3) for samples (cucumber and peach) spiked at three different levels (10, 50, and 100 µg/ kg). The detection limit (signal/noise = 3) ranged from 0.01 to 0.08 µg/kg. The results demonstrated good potential use of this convenient and highly efficient method for determining trace strobilurin fungicides in agricultural products.

[Safety and Tolerance of Healthy People to Injection of Astragalosides-a New Drug for Coronary Heart Disease].

OBJECTIVES: To assess the safety and tolerance of healthy volunteers to as tragalosides injection (AGI), and to determine a safe dose range for phase II clinical trial. METHODS: A total of 62 healthy volunteers participated in this study, with 26 being given a single AGI of 100 mL, 200 mL, 300 mL, 400 mL, 500 mL, or 600 mL and 36 subjects being given 500 mL, 400 mL, 200 mL or 300 mL of AGI once a day for 7 d. Discomfortsymptoms, vital signs and safety problems were recorded 3 d and 7 d after the administration of AGI. The results were analyzed. RESULTS: Of the 62 participants, 40 adverse events (AEs) were reported by 31 participants, which included 23 mild adverse reactions (ADRs) and 4 moderate ADRs. Nine AEs were reported by 9 participants with single AGI, including 7 ADRs. Fourteen AEs were reported by 10 participants with 500 mL and 400 mL multiple AGI, including 12 ADRs occurred in 9 participants.Seventeen AEs were reported by 12 participants with 300 mL and 300 mL multiple AGI, including 3 mild ADRs. The main ADRs included abnormal liver function [slightly elevated glutamic pyruvic transaminase (ALT), glutamic oxaloacetic transaminase (AST),and serum total bilirubin (TBil)], low blood potassium, increased urine red blood cell count, rash, and phlebitis. CONCLUSIONS: The maximum tolerance is 600 mL for single-dose treatment, and 400 mL for multiple-dose (7 d). The dose guidance given in this study should be examined its effects and safety in patients with coronary heart disease in phase II clinical trial.

Highly efficient synthesis of novel methyl 13(2)-methylene mesopyropheophorbide a and its stereoselective Michael addition reaction.

Treatment of methyl mesopyropheophorbide a with formaldehyde under basic conditions gave a novel 13(2)-methylene derivative in 85% yield; under acidic conditions, the corresponding 20-hydroxymethyl derivative was obtained in 65% yield. The high reactivity of the enone structural motif existed in the former product provides a unique way to construct some novel chlorophyll a derivatives for various applications. Stereoselective Michael reaction of this compound is studied and discussed.

Synthesis, optical properties and preliminary in vitro photodynamic effect of pyridyl and quinoxalyl substituted chlorins.

A series of chlorophyll a-based chlorins conjugated with pyridyl or quinoxalyl group at different positions were synthesized, characterized and evaluated for their photodynamic effect in vitro. It was found that all the pyridyl and quinoxalyl chlorins showed promising photocytotoxicities but nontoxic without irradiation in HeLa cells, and the substituted types and positions had a significant influence on the photocytotoxicities of the chlorophyll a-based chlorins. All the chlorins with a pyridyl group at the C-D ring end exhibited relatively high photocytotoxicity as compared to those with 3(2)-pyridyl. Among them, compound 12 conjugated with a pyridyl group at its C12 position showed the best photodynamic effect in HeLa cells with an IC50 value of 0.033µM. These facts, associated with the relative high long wavelength absorptions of those chlorins may provide valuable ways to design and prepare promising photosensitizers for application in photodynamic therapy.

Hydroxyethylcellulose-Directed Synthesis of Gold Microplates with Hydrogen Peroxide in an Aqueous Phase.

In this study, we successfully synthesized well-defined polygonal gold microplates for the first time in an aqueous phase using hydroxyethylcellulose (HEC) in the presence of hydrogen peroxide (H2O2). HEC played a pivotal role during the synthesis, acting not only as a biotemplate but also as an in situ reduction site for the nucleation and growth of gold (Au) microplates. H2O2 played a crucial role in accelerating the growth of Au microplates from the Au nucleus. This methodology is ecofriendly and easy to operate and has potential applications in various fields, such as electronics, photonics, and biotechnology.

Halide-Salt-Free Synthesis of Silver Nanowires with High Yield and Purity for Transparent Conductive Films.

To date, silver nanowires (AgNWs) are routinely synthesized. However, the controllable preparation of AgNWs without any halide salts has not reached a similar level. In particular, the halide-salt-free polyol synthesis of AgNWs commonly occurs above 413 K, and the property of AgNWs obtained is not so easy to control. In this study, a facile synthesis of AgNWs with a yield of up to ∼90% in an average length of 75 µm was successfully performed without any halide salts. The fabricated AgNW transparent conductive films (TCFs) show a transmittance of 81.7% (92.3% for the AgNW network only without substrate) at a sheet resistance of 12.25 Ω/square. In addition, the AgNW films show distinguished mechanical properties. More importantly, the reaction mechanism for AgNWs was briefly discussed, and the importance of reaction temperature, the mass ratio of poly(vinylpyrrolidone) (PVP)/AgNO3, and the atmosphere was emphasized. This knowledge will help enhance the reproducibility and scalability of polyol synthesis of high-quality AgNWs.

Neuroprotective effect of fucoidan on H2O2-induced apoptosis in PC12 cells via activation of PI3K/Akt pathway.

One of the plausible ways to prevent the reactive oxygen species (ROS)-mediated cellular injury is dietary or pharmaceutical augmentation of endogenous antioxidant defense capacity. In this study, we investigated the neuroprotective effect of fucoidan on H(2)O(2)-induced apoptosis in PC12 cells and the possible signaling pathways involved. The results showed that fucoidan inhibited the decrease of cell viability, scavenged ROS formation and reduced lactate dehydrogenase release in H(2)O(2)-induced PC12 cells. These changes were associated with an increase in superoxide dismutase and glutathione peroxidase activity, and reduction in malondialdehyde. In addition, fucoidan treatment inhibited apoptosis in H(2)O(2)-induced PC12 cells by increasing the Bcl-2/Bax ratio and decreasing active caspase-3 expression, as well as enhancing Akt phosphorylation (p-Akt). However, the protection of fucoidan on cell survival, p-Akt, the Bcl-2/Bax ratio and caspase-3 activity were abolished by pretreating with phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002. In consequence, fucoidan might protect the neurocytes against H(2)O(2)-induced apoptosis via reducing ROS levels and activating PI3K/Akt signaling pathway.

Acute and subchronic toxicity of xylo-oligosaccharide in mice and rats.

Xylo-oligosaccharide (XOS) is sugar oligomers composed of a ß-1,4-linked xylopyranosyl backbone that are obtained by either chemical or, more commonly, enzymatic hydrolysis of xylan polysaccharides extracted from plant cell wall. In this study, acute and subchronic toxicity of XOS in mice and rats have been evaluated, respectively. In the acute study, no obvious clinical signs of toxicity or mortality were observed in mice at the dosage of 32 g/kg BW XOS, excepting transient unformed stools were observed. In the subchronic study, XOS was evaluated in rats with dietary administration at concentrations of 0 (control), 0.9, 2.9, 8.8 and 10% for 13 weeks. Measurements included clinical observations, body weight, food consumption, food conversion efficiency, hematology, blood chemistry, gross necropsy, organ weight and histopathology. Under the conditions, no treatment-related changes were noted in behavior or appearance of the rats and no mortalities occurred. No toxicological findings were found in food consumption, food conversion efficiency, hematology, clinical biochemistry or organ weights in either sex. It is concluded, therefore, that the high dose level, at which the female and male rats consumed about 11.51 and 14.95 g XOS/kg bw/d, respectively, is the no observed adverse effect level (NOAEL) of this 13-week toxicity study.

Ferric Chloride-Induced Synthesis of Silver Nanodisks with Considerable Activity for the Reduction of 4-Nitrophenol.

Silver nanodisks (AgNDs) have been successfully synthesized by using ferric chloride as an auxiliary agent in the presence of polyvinylpyrrolidone and N,N-dimethylformamide as both a solvent and a reducing agent. The mass ratio of reactants, temperature, and time were demonstrated to be the key factors determining the morphology of the product, and the conversion of Fe3+/Fe2+ ions played an important role in increasing the ratio of silver nanosheets (AgNSs). As the reaction prolonged, the etching effect of Cl- ions on the tips of AgNSs became more and more obvious, which made the obtained typical polygonal AgNSs turn into AgNDs eventually. In addition, the prepared AgNDs exhibited a considerable catalytic activity in the reduction of 4-nitrophenol.

Synthesis and the growth mechanism of ultrafine silver nanowires by using 5-chloro-2-thienylmagnesium bromide as the additive.

Synthesis of silver nanowires (Ag NWs) has been studied for decades. However, Ag NWs with diameters below 20 nm synthesised by simple and robust approaches are still rarely reported. In this work, Ag NWs with an average diameter of ∼15 nm and an aspect ratio of over 1000 have been prepared by using a Grignard reagent 5-chloro-2-thienylmagnesium bromide as an assistant additive. In particular, the presence of 5-chloro-2-thienylmagnesium bromide is proven to be beneficial for the in situ formation of smaller AgBr and AgCl particles step by step in comparison with traditional inorganic halide ions, and then promote the final growth of ultrafine Ag NWs.

Preparation of magnetic zeolitic imidazolate framework-8 for magnetic solid-phase extraction of strobilurin fungicides from environmental water samples.

In this paper, magnetic zeolitic imidazolate framework-8 composites were synthesized by a simple in situ method and then used for the first time as an adsorbent in magnetic solid-phase extraction for extracting multiple strobilurin fungicides. The magnetic composites were characterized in detail. The results showed that Fe3O4 nanoparticles were attached on the surface of zeolitic imidazolate framework-8 with a uniform particle size of 150-200 nm and that the magnetic composites possessed a perfect molecular transfer rate towards strobilurin fungicides. The parameters of the magnetic solid-phase extraction process, including solution pH, adsorption time, solution volume, elution solvent, and elution volume, were investigated. Under the optimum conditions, the recoveries of all five fungicides fell within the range 80.8-109.0% with spiking levels of 10, 20 and 50 ng mL-1. A magnetic solid-phase extraction-high performance liquid chromatography-tandem mass spectrometry method based on the magnetic composites was established and confirmed to be simple, time-efficient and highly sensitive.

Preparation of magnetic flower-like molybdenum disulfide hybrid materials for the extraction of organophosphorus pesticides from environmental water samples.

In this study, the magnetic flower-like molybdenum disulfide hybrid materials (Fe3O4/MoS2) were successfully synthesized by in-situ fabrication method and utilized in the magnetic solid-phase extraction of organophosphorus pesticides. Fe3O4 nanoparticles with different loading amounts of MoS2 were evaluated and detail characterized. The results showed that MoS2 played a key role with rapid and high adsorption capacity towards organophosphorus pesticides. The higher extraction efficiency and good magnetic performance were obtained with loading amount of 200 mg MoS2. Fe3O4 was attached on the surface of MoS2 with flower-like shape (500 nm in diameter). The parameters (amounts of adsorbents, adsorption time, solution pH, elution solvents and sample volumes) affecting magnetic solid-phase extraction efficiency were optimized. Under the optimum conditions, magnetic solid-phase extraction coupled with high liquid chromatography-tandem mass spectrometry for analyzing organophosphorus pesticides in environmental water samples was established. All the analytes exhibited good recoveries spiked at three different concentration levels (10, 20, 50 ng/mL) in water samples. The relative standard deviations were between 1.4% and 6.8%. The developed method showed high sensitivity and good potential use of this convenient and high efficient method for determining organophosphorus pesticides. More importantly, this study can provide a new magnetic adsorbent with extremely fast mass transfer rate for other potential trace contaminants.

Preparation of magnetic zeolitic imidazolate framework-67 composites for the extraction of phthalate esters from environmental water samples.

In this paper, magnetic ZIF-67 composites were prepared by an in situ method and utilized in the magnetic solid-phase extraction of phthalate esters. The obtained magnetic ZIF-67 composites were characterized in detail, and the adsorption performance was evaluated. The results showed that ZIF-67 crystals in the composites had a chamfered cubic shape with about 2.0 µm diameter and Fe3O4 was attached on the surface of ZIF-67. The parameters affecting magnetic solid-phase extraction efficiency were optimized including the adsorption and desorption conditions. Under the optimum conditions, magnetic solid-phase extraction coupled with gas chromatography-mass spectrometry for analyzing seven phthalate esters in environmental water samples was established. All the analytes exhibited good linearity (1-200 ng mL-1) with correlation coefficients higher than 0.9950. The relative standard deviations were between 4.3% and 8.9%. The developed method showed high sensitivity and had good potential for analyzing trace phthalate esters in water samples.

Synthesis of dummy-template molecularly imprinted polymer adsorbents for solid phase extraction of aminoglycosides antibiotics from environmental water samples.

A novel dummy molecularly imprinted polymers (DMIPs) for aminoglycoside antibiotics (AAs) was prepared for the first time by precipitation polymerization using raffinose as template molecule, methacrylic acid as functional monomer and trimethylolpropane triacrylate as cross-linker. The obtained DMIPs were characterized in detail, and their adsorbing and recognition performance were evaluated. The results showed that the DMIPs exhibited specific recognition towards six AAs with large adsorption capacity. The dummy molecularly imprinted solid phase extraction (DMISPE) conditions including elution/washing solutions and sample loading volumes were optimized. Under optimum conditions, a convenient and efficient method for the determination of AAs in environmental water samples based on DMISPE coupling with hydrophilic interaction-high performance liquid chromatography-tandem mass spectrometry was established. The developed method showed good linearity with correlation coefficients higher than 0.9921 for all the analytes and good recoveries (70.8-108.3%) with relative standard deviations from 2.6 to 11.4% spiked at three different concentration levels in water samples. The limit of detection (S/N = 3) ranged from 0.006 to 0.6 ng/mL. The results demonstrated good potential of DMIPs for sample pretreatment of trace AAs in environmental water samples.

Co-encapsulation of curcumin and resveratrol into novel nutraceutical hyalurosomes nano-food delivery system based on oligo-hyaluronic acid-curcumin polymer.

In this work, in order to enhance the stability, bioavailability and antioxidant activity of insoluble antioxidants used into juice, yoghourt and nutritional supplements, the oligo-hyalurosomes nano-delivery system (CRHs) based on oligo-hyaluronic acid -curcumin (oHC) polymer loaded curcumin(Cur) and resveratrol (Res) was fabricated with new nanotechnolgy. The rosy biodegradable amphiphilic oHC polymer was successfully synthesized and used to fabricate the hyalurosomes containing both Cur and Res, called CRHs. The CRHs can spontaneously self-assemble into nano-sized spherical shape of average particle size 134.5±5.1nm and Zeta potential -29.4±1.2 at pH 7.4 PBS conditions. In vitro gastrointestinal release test showed a perfect stability and outstanding sustained release character. Moreover, compared to the single formulations and liposomes, CRHs showed a dose-dependent manner with a higher radical scavenging activity. Therefore, the novel CRHs nano-food manifested the hopeful properties for the new effective gastrointestinal formulation and promising new nano-food delivery system in the use of juice, yoghourt and nutritional supplements.

Enhancing the response rate of strand displacement-based electrochemical aptamer sensors using bivalent binding aptamer-cDNA probes.

Electrochemical aptamer (EA) sensors based on aptamer-cDNA duplex probes (cDNA: complementary DNA) and target induced strand displacement (TISD) recognition are sensitive, selective and capable of detecting a wide variety of target analytes. While substantial research efforts have focused on engineering of new signaling mechanisms for the improvement of sensor sensitivity, little attention was paid to the enhancement of sensor response rate. Typically, the previous TISD based EA sensors exhibited relatively long response times larger than 30min, which mainly resulted from the suboptimal aptamer-cDNA probe structure in which most of aptamer bases were paired to the cDNA bases. In an effort to improve the response rate of this type of sensors, we report here the rational engineering of a quickly responsive and sensitive aptamer-cDNA probe by employing the conception of bivalent interaction in supramolecular chemistry. We design a bivalent cDNA strand through linking two short monovalent cDNA sequences, and it is simultaneously hybridized to two electrode-immobilized aptamer probes to form a bivalent binding (BB) aptamer-cDNA probe. This class of BB probe possesses the advantages of less aptamer bases paired to the cDNA bases for quick response rate and good structural stability for high sensor sensitivity. By use of the rationally designed BB aptamer-cDNA probe, a TISD based EA sensor against ATP with significantly enhanced response rate (with a displacement equilibrium time of 4min) and high sensitivity was successfully constructed. We believe that our BB probe conception will help guide future designs and applications of TISD based EA sensors.