Two machine learning approaches for predicting cyanobacteria abundance in aquaculture ponds.

Cyanobacteria blooms in aquaculture ponds harm the harvesting of aquatic animals and threaten human health. Therefore, it is crucial to identify key drivers and develop methods to predict cyanobacteria blooms in aquaculture water management. In this study, we analyzed monitoring data from 331 aquaculture ponds in central China and developed two machine learning models - the least absolute shrinkage and selection operator (LASSO) regression model and the random forest (RF) model - to predict cyanobacterial abundance by identifying the key drivers. Simulation results demonstrated that both machine learning models are feasible for predicting cyanobacterial abundance in aquaculture ponds. The LASSO model (R2 = 0.918, MSE = 0.354) outperformed the RF model (R2 = 0.798, MSE = 0.875) in predicting cyanobacteria abundance. Farmers with well-equipped aquaculture ponds that have abundant water monitoring data can use the nine environmental variables identified by the LASSO model as an operational solution to accurately predict cyanobacteria abundance. For crude ponds with limited monitoring data, the three environmental variables identified by the RF model provide a convenient solution for useful cyanobacteria prediction. Our findings revealed that chemical oxygen demand (COD) and total organic carbon (TOC) were the two most important predictors in both models, indicating that organic carbon concentration had a close relationship with cyanobacteria growth and should be considered a key metric in water monitoring and pond management of these aquaculture ponds. We suggest that monitoring of organic carbon coupled with phosphorus reduction in feed usage can be an effective management approach for cyanobacteria prevention and to maintain a healthy ecological state in aquaculture ponds.

Development and application of a new 25,27-bis(L-phenylalaninemethylester-N-carbonylmethoxy)-26,28-dihydroxy-para-tert-butylcalix[4]arene stationary phase.

A 25,27-bis(L-phenylalaninemethylester-N-carbonylmethoxy)-26,28-dihydroxy- para-tert-butylcalix[4]arene-bonded silica gel stationary phase was synthesized, structurally characterized and used for LC. Its separation mechanism was studied and compared with octadecyl-bonded stationary phase, as well as our previously prepared para-tert-butylcalix[4]arene-1,2-crown-4 stationary phase. Meanwhile, the chromatographic behaviors were investigated by using polycyclic aromatic hydrocarbons, monosubstituted benzenes, anilines, phenols, Tanaka tests solutes, fluoroquinolones, and flavonoids as probes. Mechanisms involved in the chromatographic separation included hydrophobic, π-π and π-electron transfer, hydrogen bonding, and inclusion interactions. Moreover, the column was successfully employed for the analysis of the illegal additive of melamine in milk product.

Dispersive solid-phase extraction of non-steroidal anti-inflammatory drugs in water and urine samples using a magnetic ionic liquid hypercrosslinked polymer composite.

In this work, Friedel-Crafts alkylation was successfully applied to prepare a magnetic ionic liquid hypercrosslinked polymer composite (Fe3O4@IL-HCP), which was subsequently employed as magnetic solid-phase extraction (MSPE) adsorbent for the isolation and enrichment of trace non-steroidal anti-inflammatory drugs (NSAIDs). The developed composite was comprehensively characterized using various techniques, with the results indicating that it possessed high saturation magnetization (39.44 em g - 1), large specific surface area (175 m2g - 1), and high adsorption capacity for NSAIDs. The adsorption behavior and mechanisms were also investigated in detail. NSAIDs were adsorbed onto the Fe3O4@IL-HCP sorbent via a heterogeneous multilayer process consisting of hydrogen bonding and π-π and electrostatic interactions. Additionally, the composite's large surface area and multiple active sites enabled extraction equilibrium within 6 min. By coupling with high performance liquid chromatography (HPLC), the developed MSPE/HPLC method was applied for the determination of selected NSAIDs in water and urine samples. The developed method displayed wide linear ranges, low limits of detection (0.12-0.30 ng mL-1 and 0.15-1.5 ng mL-1 in water and urine samples, respectively), sufficient recoveries (92.8-109%), and good precision (relative standard deviations ≤ 4.6%). Thus, the findings of this work provide an appealing alternative for the extraction and determination of trace NSAIDs in environmental water and biological samples.

Fabrication and characterization of novel macroporous hydrogels based on the polymerizable surfactant AAc-Span80 and their enhanced drug-delivery capacity.

In this study, macroporous pH-sensitive poly[N-isopropylacrylamide-co-acrylic acid-sorbitan monooleate] hydrogels, termed as PNIPAM-co-AAc-Span80 hydrogels, with an enhanced hydrophobic property and a rich pore structure were prepared by free-radical polymerization in an ethanol/water mixture. The polymerizable surfactant AAc-Span80 was obtained by the esterification of acrylic acid (AAc) and sorbitan monooleate (Span80), which was used to copolymerize with N-isopropylacrylamide (NIPAM). The chemical structure, thermal stability, morphology, and amphipathy of the PNIPAM-co-AAc-Span80 hydrogels were characterized. The results showed that the polymerizable surfactant AAc-Span80 macromolecule introduced into the hydrogels could not only increase the hydrophobic property but also ameliorate the porous network morphology, which was conducive to high adsorption capacity for adriamycin hydrochloride (DOX). The adsorption results showed that the equilibrium adsorption capacity of DOX reached 467.5 mg g-1 within 48 h at pH 7.4, and the hydrophobic interactions and intermolecular hydrogen bonds were the main force in the adsorption process of DOX. The release results demonstrated that the macroporous pH-sensitive hydrogels loaded with DOX could release 98.7% of DOX at pH 5.0, which would be highly beneficial for the release of anti-cancer drugs in the environment of cancer cells. All the results demonstrate that the PNIPAM-co-AAc-Span80 hydrogels have great potential for the delivery of anti-cancer drugs.

Chemokines induced by PEDV infection and chemotactic effects on monocyte, T and B cells.

Porcine epidemic diarrhea virus (PEDV) is a re-emerging pathogen that causes severe economic loss in the pig industry. The host's innate immune system is the first line of defense on virus invasion of the small intestinal epithelial cells. Chemokines, as a part of the innate immune system, play an important role in host immunity against infection, however, and their expression and chemotactic effect on key immune cells in PEDV infection remains unclear. In this study, cDNA microarray was firstly performed to analyzed ileum tissue of piglets on the third day after PEDV infection. The differentially expressed genes mainly involved in multiple biological processes, chemokine signaling pathway and cytokine receptor interaction signaling pathway had the highest enrichment according to GO and KEGG enrichment analysis. The expression levels of chemokines MCP-1, MIP-1ß, IL-8, CXCL9, CXCL10 and CXCL13 in ileum of PEDV- infected piglets were significantly higher than those in the control group. The expression of chemokines in vivo experiment was further verified by RT-qPCR and ELISA using PEDV-infected IPEC-J2 cells. The results showed that the PEDV-infected IPEC-J2 cells had significantly induced protein expression of MCP-1, MIP-1ß, IL-8, CXCL9, CXCL-10 and CXCL13. These results indicated that the changes of chemokines expressed in the ileum of piglets (in vivo) were consistent with those in IPEC-J2 cells (in vitro) after PEDV infection. Finally, the role of chemokines in immune cell migration during PEDV infection was illustrated by siRNA-mediated knock down method and the co-culture model of IPEC-J2 cells with peripheral blood leukocyte cells (PBLCs). The FACS analysis showed that MCP-1 induced by PEDV infection played a chemotactic effect on CD14+ cells, CXCL9 on CD3+CD4-CD8-γδ T, CD3+CD4-CD8+ Tc, CD3+CD4+CD8- Th and CD3+CD4+CD8+ Tm subsets, and CXCL13 on CD19+ B cells. Collectively, our findings first indicate that PEDV-induced chemokines MCP-1, CXCL-9 and CXCL-13 attracted CD14+ cells, T cells and B cells, respectively. These results provide a theoretical basis for studying the mechanism of anti-PEDV infection in piglets.

Facile synthesis of magnetic sulfonated covalent organic framework composites for simultaneous dispersive solid-phase extraction and determination of ß-agonists and fluoroquinolones in food samples.

In this work, an efficient method for the determination of ß-agonists and fluoroquinolones was established, based on a mixed-mode sorbent of magnetic sulfonated covalent organic framework composites. By coupling with HPLC-MS/MS, the main factors that affect the extraction procedure were optimized. Under the optimal conditions, the proposed HPLC-MS/MS method was successfully utilized for the extraction of ß-agonists and fluoroquinolones in milk and pork meat samples. The method showed good linearities (R2 ≥ 0.9916), and low LOQs of 0.1-0.2 ng g-1 for ß-agonists and fluoroquinolones. The adsorption mechanism was investigated with the assistance of quantum chemistry calculation method, and it is worth noting that the sorbent relied mainly on the multiple adsorption mechanisms, including π-π stacking, hydrophobic, electrostatic attraction and hydrogen-bonding interactions. This work not only provides a simple method for the preparation of a mixed-mode sorbent, but also a routine analysis strategy for monitoring the illegal use of ß-agonists and fluoroquinolones.

Fluorine-Free Waterborne Coating for Environmentally Friendly, Robustly Water-Resistant, and Highly Breathable Fibrous Textiles.

Waterproof and breathable membranes (WBMs) with simultaneous environmental friendliness and high performance are highly desirable in a broad range of applications; however, creating such materials still remains a tough challenge. Herein, we present a facile and scalable strategy to fabricate fluorine-free, efficient, and biodegradable WBMs via step-by-step dip-coating and heat curing technology. The hyperbranched polymer (ECO) coating containing long hydrocarbon chains provided an electrospun cellulose acetate (CA) fibrous matrix with high hydrophobicity; meanwhile, the blocked isocyanate cross-linker (BIC) coating ensured the strong attachment of hydrocarbon segments on CA surfaces. The resulting membranes (TCA) exhibited integrated properties with waterproofness of 102.9 kPa, breathability of 12.3 kg m-2 d-1, and tensile strength of 16.0 MPa, which are much superior to that of previously reported fluorine-free fibrous materials. Furthermore, TCA membranes can sustain hydrophobicity after exposure to various harsh environments. More importantly, the present strategy proved to be universally applicable and effective to several other hydrophilic fibrous substrates. This work not only highlights the material design and preparation but also provides environmentally friendly and high-performance WBMs with great potential application prospects for a variety of fields.

Removal characteristics of two anionic dyes by a polyethylenimine/poly(N,N-dimethylaminoethyl methacrylate) gel.

The highly efficient gel obtained via the copolymerization of polyethylenimine (PEI) and poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) was successfully applied for the removal of two anionic dyes (amaranth and sunset yellow) from their aqueous solutions. Moreover, the results of the adsorption experiments for sunset yellow and amaranth on the PEI/PDMAEMA gel demonstrate that the adsorption equilibrium both could be achieved within 1 h, and the maximum adsorption capacities were 757 mg g-1 and 744 mg g-1 under unoptimized conditions, respectively. Moreover, the PEI/PDMAEMA composite gel was found to be pH-sensitive and the addition of salts together with ionic strength were also explored for understanding the adsorption performance. In addition, it can be found from the studies of adsorption mechanism that it is mainly electrostatic adsorption; moreover, the separation process conforms to the Langmuir adsorption isotherm model and the pseudo second-order kinetic model, which is a spontaneous endothermic process. When the PEI/PDMAEMA gel was used in continuous flow column, it could handle large volumes of dye solution with very low concentrations due to its strong enrichment capacity. Finally, the desorption experiments show that the PEI/PDMAEMA gel is easier to regenerate and has a longer lifetime. Therefore, the high adsorption capacity and easy operation of adsorption for amaranth and sunset yellow on the PEI/PDMAEMA gel make it a potential application prospect for the practical removal of other kinds of similar pollutants.

Facile fabrication of fluorine-free breathable poly(methylhydrosiloxane)/polyurethane fibrous membranes with enhanced water-resistant capability.

HYPOTHESIS: Ideal breathable and waterproof materials contain two key elements: hydrophobic matrix and small pore size. Current high-performing breathable waterproof membranes usually employ fluorinated materials to construct hydrophobic surface, which possess alarming potential environmental hazards. Fluorine-free waterproof agents through coating treatment to obtain hydrophobicity suffer from complicated fabrication process and poor durability. Hence, non-fluorinated chemicals incorporated into fibers via a facile one-step electrospinning may be an effective approach to attain durable hydrophobic membranes. EXPERIMENTS: Poly(methylhydrosiloxane)/polyurethane (PMHS/PU) solution with various PMHS concentration was formulated and electrospun to fibrous membranes, followed by a facile thermal treatment process. A systematic study including morphologies, porous structure, and surface wettability was performed. Breathable waterproof performance and tensile strength were also investigated. FINDINGS: Added PMHS imparted mighty hydrophobicity to the membranes with a water contact angle of 130.2°, and the subsequent heat treatment greatly improved waterproofness, meanwhile doubled the tensile strength. The resultant membranes exhibited robust hydrostatic pressure of 54.1 kPa, medium breathability of 9.5 kg m-2 d-1, and excellent stretching stress of 14.1 MPa, which can meet the requirements of general use. The presented strategy on membrane fabrication is feasible and scalable, which may be considered as an effective remedy for environmental protection.

Simultaneous determination of 13 aminoglycoside residues in foods of animal origin by liquid chromatography-electrospray ionization tandem mass spectrometry with two consecutive solid-phase extraction steps.

A confirmatory and quantitative method based on liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) has been developed for simultaneous determination of 13 aminoglycoside antibiotics in various samples. The aminoglycoside analytes were released and extracted from different matrices with 5% trichloroacetic acid. The influence of pH values on the solid-phase exaction (SPE) procedure has been studied. Due to different pK(a) values of the compounds, seven aminoglycosides (AGs) were quantitatively retained on Oasis HLB cartridges at pH<1 and then six aminoglycosides were retained at pH 8.5. Thus, the combination of two HLB SPE cartridges with different pH values was involved to simultaneously purify 13 aminoglycosides. The proposed two SPE steps produced high recovery yields for every aminoglycoside in five different matrices. The LC-MS/MS method was validated according to the European Union Commission directive 2002/657/EC. Good performance characteristics were obtained for recovery, precision, calibration curve, stability, specificity, decision limits (CCalpha) and detection capabilities (CCbeta) in different matrices. The optimized procedure has been successfully applied to real samples in our laboratories (n> or =200) for 1 year. It demonstrated that the new method was robust and useful for identification and quantification of 13 aminoglycosides residues in foods of animal origin.

Rapid determination of 88 veterinary drug residues in milk using automated TurborFlow online clean-up mode coupled to liquid chromatography-tandem mass spectrometry.

A novel method based on TurborFlow online solid phase extraction (SPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been established for simultaneous screening and confirmation of 88 wide-range veterinary drugs belonging to eight families (20 sulfonamides, 7 macrolides, 15 quinolones, 8 penicillins, 13 benzimidazoles, 4 tetracyclines, 2 sedatives, and 19 hormones) in milk. The preparation method consists of sample dilution and ultrasonic extraction, followed by an automated turbulent flow cyclone chromatography sample clean-up system. The detection was achieved in selected reaction monitoring mode (SRM). The total run time was within 39 min, including automated extraction, analytical chromatography and re-equilibration of the turboflow system. The optimization of different experimental parameters including extraction, purification, separation, and detection were evaluated separately in this study. The developed method was validated and good performing characteristics were obtained. The linear regression coefficients (R(2)) of matrix-match calibration standard curves established for quantification were higher than 0.9930. The limits of detection (LOD) were in the range of 0.2-2.0 µg/kg given by signal-noise ratio ≥3 (S/N) and the limits of quantification (LOQ, S/N≥10) ranged between 0.5 µg/kg and 10 µg/kg. Average recoveries of spiked target compounds with different levels were between 63.1% and 117.4%, with percentage relative standard deviations (RSD) in the range of 3.3-17.6%. The results indicated that the developed method has great potential for the routine laboratory analysis of large numbers of samples on measuring different classes of compounds. In comparison to traditional procedures, the automated sample clean-up ensures rapid, effective, sensitive analyses of veterinary drugs in milk.

[Determination of poppy ingredients in chafing dish materials by isotopic internal standard coupled with multiple reaction monitoring and online full scan mass spectrometry].

A confirmative method was developed for determining five poppy alkaloids including morphine, codeine, papaverine, tibane, noscapine in chafing dish ingredients by high performance liquid chromatography coupled with triple quadrupole linear ion trap mass spectrometry (HPLC-Q Trap MS). The sample was extracted with dilute HCl solution under heating condition. The removal of lipid procedure was performed with hexane. The purification was carried out on a mixed-cation solid-phase extraction column (MCX) and ethyl acetate-methanol containing 5% aqueous ammonia was used for elution. A PAK ST column was used to separate the analytes, and 5 mmol/L ammonium acetate methanol and 10 mmol/L ammonium acetate (pH 3. 6) were used as mobile phases. The five alkaloids was detected in the positive mode simultaneously by multiple reaction monitoring (MRM) and online enhanced product ion full scan (EPI). The LODs were 0.05-0.5 µg/kg and the LOQs were 0. 2-2 µg/kg for the five poppy alkaloids. The overall recoveries of the method varied from 64. 2% to 110. 6%, and the RSD were between 4. 2% and 12. 5%. The EPI mass spectra of positive samples were searched through standard library for qualitative confirmation. The detection of real hot pot material samples showed this method can be used for the simple and accurate determination of the five poppy alkaloid residues in chafing dish.

[Rapid determination of total residues of ribavirin and its metabolites in chicken and chicken products by ultra-performance hydrophilic interaction chromatography-tandem mass spectrometry].

An analytical method was developed for the determination of total residues of ribavirin and its phosphorylated metabolites in chicken and its products by hydrophilic interaction chromatography-tandem mass spectrometry. The samples were extracted with acetonitrile containing 1% (v/v) acetic acid under ultrasonic condition and then enzymatically hydrolysed with acid phosphatase at 37 degrees C. After liposoluble substances being removed with hexane, C18 and PSA dispersion solid phase extraction (DSPE) was introduced to cleanup procedures. The separation was performed on an ultra-performance hydrophilic interaction chromatographic (HILIC) amide column under a gradient elution using acetonitrile and 0.1% formic acid. The analytes were detected in the positive electrospray ionization and multi-reaction monitoring (MRM) mode. In the range of 1-200 microg/kg, the correlation coefficient was greater than 0.999. The limit of detection (LOD, S/N > or = 3) was 1 microg/kg and the limit of quantification (LOQ, S/N > or = 10) was 5 microg/kg. The recoveries of ribavirin spiked at three levels ranged from 67.8% to 112.7% with the relative standard deviations (RSDs) of 6.1%-13.6%. The results of the determination of ribavirin in various real samples showed that the method is simple, rapid, accurate and suitable for the determination of total residues of ribavirin and its metabolites in chicken and its products.

[Simultaneous determination of 11 aminophenols in hair dyes by high performance liquid chromatography].

An analytical method was developed for the simultaneous determination of 11 aminophenols in direct and oxidized hair dyes by high performance liquid chromatography (HPLC). The samples were extracted with methanol using sodium bisulfite for anti-oxidation. The purification was carried out with the high speed frozen centrifugation. The separation was performed on an Agilent Zorbax SB C18 column with the mobile phases of acetonitrile and an ion pair system of sodium heptanesulfonate and phosphate under a gradient elution. The analytes were detected at three different wavelengths of 230, 270 and 400 nm. In the concentration range of 0.05 - 500 mg/L, the correlation coefficients for the 11 aminophenols were not less than 0.9992. The limits of quantification including 4-amino-3-nitrophenol, 2-amino-5-nitrophenol, and 4-(2-hydroxyethyl) amino-3-nitrophenol were 5 mg/kg. Other aminophenols including 4-aminophenol, 4-methyl aminophenol, 3-aminophenol, 2-aminophenol, 5-amino-o-cresol, 4-amino-3-methylphenol, 5-(2-hydroxyethyl) amino-o-cresol and 2-amino-4-nitrophenol were 20 mg/kg. The recoveries of the aminophenols spiked at different levels ranged from 88.5% to 109. 5% with the relative standard deviations (RSDs) within the range of 2.2% - 8.3%. The commercially available hair dye samples were analyzed for the aminophenols and the results showed that the method was suitable for the determination of the 11 aminophenols in direct and oxidized hair dyes.

[Determination of four triorganotin residues in leather products by ultra performance liquid chromatography-tandem mass spectrometry and cation solid-phase extraction].

A confirmative method was developed for the determination of four triorganotins (TOTs) included tributyltin (TBT), triphenyltin (TPhT), di-triphenyltin oxide (DTPhT), and cyhexatin (CYT) in leather products by cation solid-phase extraction (SPE) and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The organotin residues were extracted with HCl solution. The ionized compounds were purified with SPE. The reconstituted sample solution was analyzed by UPLC-MS/MS in positive ion electrospray and multi-reaction monitor (MRM) mode, with a UPLC C18 column as the separation column. The limits of quantification were 10 microg/kg for TBT, TPhT, DTPhT (calculated as TPhT) and 20 microg/kg for CYT. The method was validated at three levels for each compound. The recoveries were from 54.1% to 101.4%, and the relative standard deviations (RSD) were between 4.3% and 9.8%. The method is simple, reliable and accurate. It can meet the requirements of the domestic and international legislations. The method adapts to simultaneously confirm the residues of the four TOTs in leather products.

[Quick determination of 39 hormones residues in infant formula by liquid chromatography-tandem mass spectrometry].

A quick confirmative method was developed for determining the residues of 17 glucocorticoids, 11 progesterones, 3 androgens and 8 estrogens in infant formula by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). The sample was extracted with acetonitrile at first. Then the lipid substances were removed by centrifugation under freezing condition and liquid-liquid extraction with hexane of the extract. The purification was carried out on hydrophilic-lipophilic solid-phase extraction columns and methanol was used as the eluted solvent. The detection of 39 analytes was carried out in the positive or negative multi-reaction monitoring (MRM) mode, separately. Acetonitrile-0.1% formic acid was used as the mobile phase and an ordinary silica gel C18 column was selected to separate the analytes in the positive mode. Acetonitrile-0.1% aqueous ammonia as mobile phase and the separation was carried out on an ultra-performance C18 column with a wide pH range in the negative mode. The limits of quantification (LOQ, S/N > or = 10) were 0.02-5 microg/kg. The overall recoveries varied from 59.5% to 117.9%, and the relative standard deviations (RSD) were between 6.4% and 16.3%. The real sample tests showed that the simple and accurate method can be used for determining the residues of multi-endogenous and chemically synthesized hormones in milk powders.