[Simultaneous determination of 31 banned veterinary drugs during egg-laying period in poultry eggs by ultra performance liquid chromatography-tandem mass spectrometry].

The consumption of poultry eggs has increased in recent years owing to the abundance of production and improvements in living standards. Thus, the safety requirements of poultry eggs have gradually increased. At present, few reports on analytical methods to determine banned veterinary drugs during egg-laying period in poultry eggs have been published. Therefore, establishing high-throughput and efficient screening methods to monitor banned veterinary drugs during egg-laying period is imperative. In this study, an analytical method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with QuEChERS-based techniques was developed for the simultaneous determination of 31 banned veterinary drugs encompassing nine drug classes (macrolides, antipyretic and analgesic drugs, sulfonamides, antibacterial synergists, anticoccidials, antinematodes, quinolones, tetracyclines, amphenicols) in different types of poultry eggs. The main factors affecting the response, recovery, and sensitivity of the method, such as the extraction solvent, purification adsorbent, LC separation conditions, and MS/MS parameters, were optimized during sample pretreatment and instrumental analysis. The 31 veterinary drug residues in 2.00 g eggs were extracted with 2 mL of 0.1 mol/L ethylene diamine tetraacetic acid disodium solution and 8 mL 3% acetic acid acetonitrile solution, and salted out with 2 g of sodium chloride. After centrifugation, 5 mL of the supernatant was cleaned-up using the QuEChERS method with 100 mg of octadecylsilane-bonded silica gel (C18), 50 mg of N-propylethylenediamine (PSA), and 50 mg of NH2-based sorbents. After nitrogen blowing and redissolution, the 31 target analytes were separated on a Waters CORTECS UPLC C18 analytical chromatographic column (150 mm×2.1 mm, 1.8 µm) at a flow rate, column temperature, and injection volume of 0.4 mL/min, 30 ℃, and 5 µL, respectively. Among these analytes, 26 analytes were acquired in dynamic multiple reaction monitoring (MRM) mode under positive electrospray ionization (ESI+) conditions using (A) 5 mmol/L ammonium acetate (pH 4.5) and (B) acetonitrile as mobile phases. The gradient elution program was as follows: 0-2.0 min, 12%B-30%B; 2.0-7.5 min, 30%B-50%B; 7.5-10.0 min, 50%B; 10.0-10.1 min, 50%B-100%B; 10.1-12.0 min, 100%B; 12.0-12.1 min, 100%B-12%B; The five other target analytes were acquired in MRM mode under negative electrospray ionization (ESI-) conditions using (A) H2O and (B) acetonitrile as mobile phases. The gradient elution program was as follows: 0-2.0 min, 12%B-40%B; 2.0-6.0 min, 40%B-80%B; 6.0-6.1 min, 80%B-100%B; 6.1-8.0 min, 100%B; 8.0-8.1 min, 100%B-12%B. Matrix-matched external standard calibration was used for quantification. The results showed that all the compounds had good linear relationships within their respective ranges, with correlation coefficients of >0.99. The limits of detection (LODs) and quantitation (LOQs) were 0.3-3.0 µg/kg and 1.0-10.0 µg/kg, respectively. The average recoveries of the 31 banned veterinary drugs spiked at three levels (LOQ, maximum residue limit (MRL), and 2MRL) in poultry eggs ranged from 61.2% to 105.7%, and the relative standard deviations (RSDs) ranged from 1.8% to 17.6%. The developed method was used to detect and analyze banned veterinary drugs in 30 commercial poultry egg samples, including 20 eggs, 5 duck eggs, and 5 goose eggs. Enrofloxacin was detected in one egg with a content of 12.3 µg/kg. The proposed method is simple, economical, practical, and capable of the simultaneous determination of multiple classes of banned veterinary drugs in poultry eggs.

Preparation, Characterization, and Performance Evaluation of Petroleum Asphalt Modified with Bio-Asphalt Containing Furfural Residue and Waste Cooking Oil.

The study aims to analyze the feasibility of proposing waste cooking oil and industrial waste furfural residue as raw materials to prepare bio-asphalt as partial substitutes for petroleum asphalt, so as to reduce the cost of pavement construction and decrease the consumption of non-renewable resources. In this study, 90# petroleum asphalt was partially substituted with the bio-asphalt in different proportions to prepare biomass-modified petroleum asphalt, the performance of which was first evaluated based on three indices: penetration, softening point, and ductility. Comparison of the crystal structures of the bio-asphalt and furfural residue were enabled by X-ray diffraction, and the blending mechanism and microscopic morphologies of the biomass-substituted asphalt mixtures were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The results showed that the bio-asphalt was hydrophobic and exhibited excellent compatibility with 90# petroleum asphalt. The partial substitution of petroleum asphalt with bio-asphalt improved the low-temperature crack resistance of the asphalt by adversely affecting the high-temperature stability of the asphalt; however, when the bio-asphalt content was 8 wt.%, the performance parameters of the biomass-modified asphalt met the requirements of the 90# petroleum asphalt standard.

A Robust Cage-Based Metal-Organic Framework Showing Ultrahigh SO2 Uptake for Efficient Removal of Trace SO2 from SO2/CO2 and SO2/CO2/N2 Mixtures.

Removal of trace SO2 from an SO2-containing product is now receiving increasing attention. However, designing a robust porous adsorbent with high SO2 adsorption capacity and good SO2/CO2 selectivity, as well as validity under humid conditions, is still a challenging task. Herein, we report a porous cage-based metal-organic framework, namely ECUT-111, which contains two distinct cages with apertures of 5.4 and 10.2 Å, respectively, and shows high a BET of up to 1493 m2/g and a pore volume of 0.629 cm3/g. Impressively, ECUT-111 enables an ultrahigh SO2 uptake of up to 11.56 mmol/g, exceeding most reported top-performing adsorbents for such a use. More importantly, complete separation of trace SO2 from SO2/CO2 and SO2/CO2/N2 mixtures, especially under humid conditions, and excellent recycle use were observed for ECUT-111, suggesting its superior application in desulfurization of SO2-containing products.

Multiclass and multiresidue screening of veterinary drugs and pesticides in infant formula using Quadrupole-Orbitrap MS with PRM scan mode.

A multiclass and multiresidue method for screening veterinary drugs and pesticides in infant formula was developed and validated using ultrahigh-performance liquid chromatography coupled to Quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-HRMS). A total of 49 veterinary drugs and pesticides investigated belong to 11 classes including antivirals, anticoccidials, macrolides, pyrethroids, insecticides, sulfonamides, beta-agonists, sedatives, thyreostats, nonsteroidal anti-inflammatory drugs, and other pharmacologically active substances. A generic sample preparation and highly selective acquisition mode of parallel reaction monitoring (PRM) were deliberately incorporated to perform efficient screening analysis. As a result, the screening target concentrations of the analytes varied from 1 to 500 µg/kg with ≤5% of false compliant rate as specified in Decision 2002/657/EC for screening analysis. The average recoveries ranged from 40.7 to 124.9% as well as the relative standard deviations from 4.2 to 26.6%, respectively. The matrix effects and interferences were effectively controlled by integrated application of dispersive solid phase extraction, PRM scan mode, and matrix-matched standard calibration. The proposed method will be helpful to provide applicable strategy for screening residues in infant formula with surveillance purpose.

Oxone-Mediated Radical C-C Bond Acetmethylation/Arylation of Methylenecyclopropanes and Vinylcyclopropanes with α-Alkyl Ketones: Facile Access to Oxoalkyl-Substituted 3,4-Dihydronaphthalenes.

An efficient oxone-mediated radical carbon-carbon σ-bond acetmethylation/arylation of methylenecyclopropanes with α-C(sp3)-H bonds of ketones is described for the preparation of 2-(2-oxopropyl)-3,4-dihydronaphthalenes. This acetmethylation/arylation undergoes a series of α-C(sp3)-H bond activation, carbon-carbon double bond acetmethylation, carbon-carbon σ-bond cleavage, and cyclization with intramolecular aromatic ring. The experimental result indicates that the carbon-carbon σ-bond acetmethylation/arylation transformation contains a radical process. The difunctionalization method can also be applied to carbon-carbon σ-bond acetmethylation/arylation of vinylcyclopropanes with ketones. This strategy offers an efficient and convenient method for acetmethylation/arylation of a carbon-carbon σ-bond with a α-carbonyl radical and an aromatic carbon in one pot, building two new carbon-carbon bonds.

Gene locations may contribute to predicting gene regulatory relationships.

We propose that locations of genes on chromosomes can contribute to the prediction of gene regulatory relationships. We constructed a time-based gene regulatory network of zebrafish cardiogenesis on the basis of a spatio-temporal neighborhood method. Through the network, specific regulatory pathways and order of gene expression during zebrafish cardiogenesis were obtained. By comparing the order with locations of these genes on chromosomes, we discovered that there exists a reversal phenomenon between the order and order of gene locations. The discovery provides an inherent rule to instruct exploration of gene regulatory relationships. Specifically, the discovery can help to predict if regulatory relationships between genes exist and contribute to evaluating the correctness of discovered gene regulatory relationships.

Photoswitching CO2 capture and release in a photochromic diarylethene metal-organic framework.

We demonstrate herein a promising pathway towards low-energy CO2 capture and release triggered by UV and visible light. A photosensitive diarylethene ligand was used to construct a photochromic diarylethene metal-organic framework (DMOF). A local photochromic reaction originating from the framework movement induced by the photoswitchable diarylethene unit resulted in record CO2-desorption capacity of 75% under static irradiation and 76% under dynamic irradiation.

Exceptional temperature-dependent coordination sites from acylamide groups.

Herein, through altering the reaction temperature, the coordination mode of the acylamide ligand is well controlled with or without the oxygen coordination site. The resulting two new coordination polymers have the formulas Cd3(L)2(bdc)3·4(H2O) (1) and Cd(L)(bdc)·2(H2O) (2) (L = N(1),N(4)-bis(pyridin-3-ylmethyl)terephthalamide, H2bdc = terephthalic acid).

Optimization of reaction conditions towards multiple types of framework isomers and periodic-increased porosity: luminescence properties and selective CO2 adsorption over N2.

Three new metal-organic frameworks (MOFs) were prepared by solvo(hydro)thermolysis and further characterized as framework isomers. The structural transformation from non-porous to porous MOFs and the purity of these products can be modulated by controlling the reaction temperature. The periodic-increased porosity observed was further confirmed by CO2 adsorption isotherms. Owing to the presence of acylamide groups in the pore walls and the flexible nature of the skeleton of these MOFs, highly selective CO2 adsorption over N2 was observed, as well as structure-dependent periodic varieties in luminescence properties.

Framework isomers controlled by the speed of crystallization: different aggregation fashions of Zn(II) and 1,2,4-triazol-3-amine, distinct (3,4)-connected self-penetrating nets, and various pore shapes.

In this work, we report two exceptional framework isomers, Zn(L)(bdc)(0.5)·0.25H2O (1, HL = 1,2,4-triazol-3-amine, H2bdc = terephthalic acid) and Zn(L)(bdc)(0.5)·0.17H2O (2), where their formation is controlled by different speeds of crystallization. Further structural studies reveal that this operation of controlling the speed of crystallization may play a profound role in determining the aggregation fashions of Zn(II) ions and L(-) ligands, resulting in the various layers, viz. a 4·8(2) net vs. a 4·6·12 net. Importantly, this work also presents two previously unobserved (3,4)-connected self-penetrating matrixes.

NHC-mediated cross-coupling of sugar-derived cyclic nitrones with enals: general and efficient synthesis of polyhydroxylated pyrrolizidines and indolizidines.

A general and efficient method for the synthesis of polyhydroxylated pyrrolizidines and indolizidines has been developed based on the NHC-catalyzed cross-coupling of sugar-derived cyclic nitrones with enals, which afforded the key intermediates, γ-hydroxyl amino esters, in good to excellent yields. Thus, a variety of polyhydroxylated pyrrolizidines and indolizidines have been synthesized and assayed against various glycosidases, which showed that aryl or alkyl substituents at C-7 of pyrrolizidines or at C-8 of indolizidines reduced the potency of the glycosidase inhibition of these bicyclic iminosugars.

Solvent-induced reversible single-crystal-to-single-crystal transformations observed in lanthanide complexes.

In this work, a rare 0D→0D single-crystal-to-single-crystal transformation (SCSC) is observed in lanthanide compounds, which is triggered by the removal or retake of solvent molecules. This advantage prompted us to explore the magnetic property of them, and some interesting magnetic properties are obtained.

A microporous metal-organic framework containing an exceptional four-connecting 4(2)6(4) topology and a combined effect for highly selective adsorption of CO2 over N2.

Reported here is a new microporous metal-organic framework, namely [Zn(2)(L)(btc)(Hbtc)] [NH(2)(CH(3))(2)]·(DMF)(2)(H(2)O)(4) (1), which is synthesized solvo(hydro)thermally by the self-assembly of Zn(NO(3))(2), N(4),N(4)-di(pyridin-3-yl)-[1,1'-biphenyl]-4,4'-dicarboxamide (L) and 1,3,5-benzenetricarboxylate acid (H(3)btc). Its topology can be described as a four-connecting 4(2)6(4) matrix containing both tetrahedral metal and ligand nodes. Interestingly, such a matrix has the same topology symbol as that observed in the well known sodalite (SOD) net, but the td10 of 434 is different from the td10 of 791 for the SOD net, indicative of an exceptional four-connecting 4(2)6(4) net. Another outstanding point is the highly selective adsorption of CO(2) over N(2), possibly contributed by a combined effect from the charged skeleton, the existence of functional groups of -CONH- and -COOH in 1.

Solvent-induced supramolecular isomers, structural diversity, and unprecedented in situ formation of both inorganic and organic ions in inorganic-organic mercury(II) complexes.

Reported here is, for the first time, an important study of solvent effect on structural diversity in inorganic-organic mercury(II) complexes. As a result, the first supramolecular isomer in mercury(II) complexes is obtained. Importantly, a previously unobserved in situ generation of both inorganic (Cl(-)) and organic ([CH(3)-L1-CH(3)](2+)) ions was also observed.

A self-catenated network containing unprecedented 0D + 2D → 2D polycatenation array.

Herein, we report a new acylamide ligand and its application in the construction of a metal-organic framework. The resultant acylamide metal-organic framework, namely [Zn(2)(L)(OH)(btc)](n) (1, L = N(1),N(4)-bis(pyridin-3-ylmethyl) naphthalene-1,4-dicarboxamide, H(3)btc = benzene-1,3,5-tricarboxylic acid), was obtained by hydrothermal synthesis. The outstanding structural feature of it is the 0D + 2D → 2D polycatenation array containing a self-catenated feature which has never previously been observed. To the best of our knowledge, the coexistence of self-catenation and polycatenation phenomena is highly exceptional.

A series of 1D Dy(III) compound showing slow magnetic relaxation: synthesis, structure, and magnetic studies.

In this work, we present the synthesis, structure, and magnetic studies of three 1D homo-spin Dy(III) compounds in detail. For 1, one crystallography-independent Dy(III) site is contained and the coordination surrounding is a distorted square-antiprism geometry. Within 2, four crystallography-independent Dy(III) sites with largely distorted square-antiprism geometry are observed. As for 3, two crystallography-independent Dy(III) sites showing bicapped triangular-prism geometry are involved. The magnetic studies suggest weak ferromagnetic interactions for 1 and weak antiferromagnetic interactions for 2 and 3. Their dynamic magnetic properties are investigated by means of alternating current (ac) susceptibility measurement, revealing their slow magnetic relaxation. Moreover, a field-dependent ac signal is observed in 1, when by applying a static dc = 1000 Oe field, strong frequency-dependent ac signals and the peak of out-of-phase (χ'') can be clearly found. Ultimately, by fitting the Arrhenius law the energy barrier and relaxation time are estimated.

The application of single-crystal-to-single-crystal transformation towards adjustable SMM properties.

Reversible single-crystal-to-single-crystal transformation (SCSC) was for the first time observed between 4f-based molecular magnets.

Chiral 1D Dy(III) compound showing slow magnetic relaxation.

Herein, we present one chiral Dy(III) compound, namely Dy(L)(3)(1, HL = 2-methylbenzoic acid), synthesized from the achiral HL ligand. Within 1, along a direction the seven-coordinated Dy(III) ion are bridged by double L carboxylate and single L oxygen to give rise to the 1D helical chain. The magnetic studies suggest small intra-chain ferromagnetic interactions. Alternating current (AC) magnetic measurements show a frequency dependence of magnetic susceptibilities in both in-phase, χ', and out-of-phase, χ''. However, no obvious peak can be found even under 1000 Oe static field, suggesting the prevalence of quantum tunnelling effect at low temperature.

KCNQ1 gain-of-function mutation in familial atrial fibrillation.

Atrial fibrillation (AF) is a common cardiac arrhythmia whose molecular etiology is poorly understood. We studied a family with hereditary persistent AF and identified the causative mutation (S140G) in the KCNQ1 (KvLQT1) gene on chromosome 11p15.5. The KCNQ1 gene encodes the pore-forming alpha subunit of the cardiac I(Ks) channel (KCNQ1/KCNE1), the KCNQ1/KCNE2 and the KCNQ1/KCNE3 potassium channels. Functional analysis of the S140G mutant revealed a gain-of-function effect on the KCNQ1/KCNE1 and the KCNQ1/KCNE2 currents, which contrasts with the dominant negative or loss-of-function effects of the KCNQ1 mutations previously identified in patients with long QT syndrome. Thus, the S140G mutation is likely to initiate and maintain AF by reducing action potential duration and effective refractory period in atrial myocytes.