Flower-like calix[6]arene-based covalent organic framework for membrane extraction of sulfonamides in animal-derived food through host-guest interaction prior to determination with ultra-high performance liquid chromatography-tandem mass spectrometry.

Supramolecular macrocycle-based covalent organic frameworks (COFs) are promising adsorbents for adsorption of hazards due to their host-guest recognition property. However, most supramolecular macrocycles are conformationally flexible, making them challenging to introduce into COFs. In this work, a calix[6]arene-based COF (CX6-BD COF) was fabricated with a unique flower-like morphology and high crystallinity. Especially, the cavity of CX6 exhibited host-guest inclusion interaction for sulfonamides (SAs), which was verified by quantum chemistry calculation. The integration of the porosity of COFs with the recognition cavity of CX6 made CX6-BD COF display excellent enrichment performance for SAs, with good enrichment factors (EFs) between 77 and 96. The material was employed as an adsorbent for COF membrane filter extraction, coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to simultaneously enrich and determine seven SAs in animal-derived food. The analytical method showed a wide linear range (0.01-100 µg/L and 0.05-100 µg/L) and low detection limits (3-10 ng/L). The established method was successfully applied to sensitively determine SAs in chicken, pork and beef samples, which achieved satisfactory recoveries (73.8-113%). These results demonstrated CX6-BD COF has good application potential in determination of trace and ultra-trace SAs in complex food matrices as an adsorbent.

Induction of tetraploids in Paper Mulberry (Broussonetia papyrifera (L.) L'Hér. ex Vent.) by colchicine.

BACKGROUND: Broussonetia papyrifera (L.) L'Hér. ex Vent. has the characteristics of strong stress resistance, high crude protein content, and pruning tolerance. It is an ecological, economic, and medicinal plant. Polyploid plants usually perform better than their corresponding diploid plants in terms of nutrients, active substances, and stress resistance. RESULTS: In this study, the leaves, calli, and seeds of diploid B. papyrifera were used for tetraploid induction by colchicine. The induction effect of colchicine on B. papyrifera was summarized through the early morphology, chromosome count and flow cytometry. It was concluded that the best induction effect (18.6%) was obtained when the leaves of B. papyrifera were treated in liquid MS (Murashige and Skoog) medium containing 450 mg·L-1 colchicine for 3 d. The comparative analysis of the growth characteristics of diploid and tetraploid B. papyrifera showed that tetraploid B. papyrifera has larger ground diameter, larger stomata, thicker palisade tissue and thicker sponge tissue than diploid B. papyrifera. In addition, the measurement of photosynthetic features also showed that tetraploids had higher chlorophyll content and higher photosynthetic rates. CONCLUSION: This study showed that tetraploid B. papyrifera could be obtained by treating leaves, callus and seeds with liquid and solid colchicine, but the induction efficiency was different. Moreover, there were differences in stomata, leaf cell structure and photosynthetic features between tetraploid B. papyrifera and its corresponding diploid. The induced tetraploid B. papyrifera can provide a technical basis and breeding material for the creation of B. papyrifera germplasm resources in the future.

Calix[4]arene-based covalent organic frameworks with host-guest recognition for selective adsorption of six per- and polyfluoroalkyl substances in food followed by UHPLC-MS/MS detection.

Long-term ingestion or exposure to food contaminated with per- and polyfluoroalkyl substances (PFASs) may cause potential harm to human health. Due to the low contents of PFASs in complex food matrices, it is of great significance to develop adsorbents with excellent properties to enrich PFASs before analysis. Herein, calix[4]arene (CX4) was used as building block to prepare ordered crystalline covalent organic frameworks (COFs). The perfect combination of the host-guest recognition ability of CX4 and the porosity of COFs makes the CX4-COFs selective and high adsorption capacity for linear molecular PFASs (261-1055 mg/g). The adsorption behavior and mechanism were verified by isotherm adsorption experiments and simulation calculations. The CX4-COFs were then used as adsorbents for membrane solid-phase extraction (M-SPE), combined with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) to determine PFASs in food. The method has low detection limits (0.11-0.28 ng/kg) and good precision (1.3%-9.8%), and has been successfully applied to the simultaneous enrichment and determination of six PFASs in fish, shrimp and shellfish. Satisfactory recoveries (79.9%-118%) were obtained. This study provides a new strategy for preparing CX4-COFs containing macrocyclic molecules with different morphologies and expands the application of COFs as attractive enrichment media for sample pretreatment.

Primary amide-functionalized cyclotricatechylene covalent organic frameworks membrane for efficient enrichment of melamine and its derivatives in migration solution of food contact materials.

A highly chemically stable primary amide-functionalized cyclotricatechylene covalent organic framework was synthesized by an irreversible reaction and a post-synthetic modification. It possessed a rod-like morphology and exhibited strong solvent stability owing to the polyether bonds. The material showed good adsorption performance for melamine and its derivatives and adsorption mechanism was investigated by molecular simulations. The adsorbent was coated on the nylon-66 membrane to prepare the enrichment membrane. Under optimized conditions, an in-syringe membrane-based extraction method, combined with ultra-high performance liquid chromatography-tandem mass spectrometry was developed for the analysis of melamine and six melamine derivatives in the migration solution. A good linearity was obtained with correlation coefficients ranging from 0.9924 to 0.9995. The limits of detection were 1-200 ng/L and the limits of quantification were 3-500 ng/L. This method was successfully applied to the migration solution of sushi bamboo rolling mats with spiked recoveries of 73.2%-115% and relative standard deviations of 0.9%-9.9%. This work shows a practical and perspective approach for the efficient enrichment of food contact material hazards.

An Efficient Propagation System through Root Cuttings of an Ecological and Economic Value Plant-Broussonetia papyrifera (L.) L'Hér. ex Vent.

Broussonetia papyrifera (L.) L'Hér. ex Vent. has considerable economic and ecological value and a long history of use in China. In this paper, root cuttings were used as the material to establish an efficient vegetative propagation of B. papyrifera. The results revealed that root segments with a diameter of 1.5~2.0 cm and a length of 20~30 cm were most suitable for shoot regeneration, as these segments had the highest adventitious shoot induction rates (93.3%), strongest adventitious shoots, and highest multiplication coefficients (7.07). With regard to the methods used for root burial, a horizontal burial at a depth of 1~3 cm yielded the best results, in this case, the adventitious shoot induction rate can reach 86.7%. The best substrate combination was perlite: peat: coconut chaff = 1:1:1 (v/v/v), wherein the adventitious shoot induction rate can reach 75.6%. The best sterilization method was mixing soil with carbendazim and soaking the root sections in carbendazim for 30 min, wherein the adventitious shoot induction rate can reach 77.8%. Adding 0.2 mg/L naphthaleneacetic acid (NAA) to 1/4 Hoagland nutrient solution significantly improved the rooting rate of adventitious shoots to 82.2%, and the survival rate of the acclimatized plants was more than 90.0%.

MOF-derived Ni3S4 Encapsulated in 3D Conductive Network for High-Performance Supercapacitor.

Transition-metal sulfide is a good kind of material for supercapacitors because of the large capacity. Nevertheless, the low electroconductivity, slow reaction kinetics, and limited active centers lead to poor electrochemical properties such as long-term cycling stability. In the present work, nano nickel metal-organic framework (Ni-MOF) was constructed by using the nitrogen-rich functional group ligand 2,4,6-tris(3,5-dicarboxylphenylamino)-1,3,5-triazin and compounded with carbon nanotubes (CNTs) to prepare Ni-MOF/CNTs composite, which was used as a precursor to prepare the MOFs-derived NC/Ni-Ni3S4/CNTs composite with the Ni3S4 uniformly distributed in the three-dimensional (3D) conductive network. The rich nitrogen doping and 3D conductive network constructed by CNTs improved the conductivity, prompted the rapid entry of electrolyte, and improved the reaction kinetics of NC/Ni-Ni3S4/CNTs, thus obtained excellent specific capacitance, coulomb efficiency, and cyclic stability. The specific capacitance of NC/Ni-Ni3S4/CNTs is 1489.9 F/g at 1 A/g, which remains 800 F/g at 10 A/g, showing good rate performance.

Updated incidence rates and risk factors of esophageal cancer in Nan'ao Island, a coastal high-risk area in southern China.

Esophageal cancer (EC) is one of the most common cancers in China. The purpose of this study was to investigate the updated incidence rates and risk factors of EC in Nan'ao Island, where the EC incidence rate was chronically the highest in southern China. To calculate the annual incidence rate, data on 338 EC cases from Nan'ao Cancer Registry system diagnosed during 2005-2011 were collected. A case-control study was conducted to explore the EC risk factors. One hundred twenty-five alive EC patients diagnosed during 2005-2011 and 250 controls were enrolled into the case-control study. A pre-test questionnaire on demography, dietary factors, drinking water treatment, and behavioral factors was applied to collect information of all participants. The average EC incidence rates during 2005-2011 were 66.09/105, 94.62/105, 36.83/105 for both genders, males and females, respectively, in Nan'ao Island. The EC incidence rate in males was 2.40- to 4.55-fold higher than that in females in the period from 2006 to 2011 (P < 0.05). Considering the onset age, males tend to be much younger than females and reached peak incidence rate at a younger age (P < 0.05). Drinking water treatment by filter (odds ratio [OR] = 0.28, 95% confidence interval [95% CI] = 0.13-0.58) and fruit consumption (OR = 0.55, 95% CI = 0.32-0.94) reduced the risk for EC. On the contrary, the pickled vegetables consumption (OR = 2.64, 95% CI = 1.46-4.76) and liquor drinking (OR = 2.32, 95% CI = 1.21-4.44) increased the risk for EC. These results may be of importance for future research on EC etiology and prevention strategies.

[Pharmacological Effects of Different Prepared Typhonii Rhizoma].

Objective: To evaluate the different actions of crude and prepared Typhonii Rhizoma through pharmacological and statistical methods. Methods: Spontaneous activity test, sleep test, and seizure induced by dimefline in mice were used to examine the sedative and anticonvulsant effects of different prepared products of Typhonii Rhizoma. Twisting induced by acetic acid, law pain induced by formaldehyde, and ear swelling caused by xylene were applied to examine the anti-inflammatory and analgesic effects of those different prepared products. Then the pharmacological effects of different prepared Typhonii Rhizoma were comprehensively analyzed by principal components analysis method. Results: Typhonii Rhizoma significantly reduced the spontaneous activities of mice, prolonged the convulsions latency,decreased twisting times, licking time and ear swelling. The principal components analysis results showed that the sample order from strong to weak was Typhonii Rhizoma prepared by ginger and alum, prepared by alum,crude Typhonii Rhizoma, and those prepared by ginger. Conclusion: Crude and prepared Typhonii Rhizoma exert sedative, anticonvulsant, analgesic and anti-inflammatory effects in different degrees.