Prediction model for severe maternal morbidity in pregnant women with hypertensive disorders of pregnancy.

Objectives: To investigate risk factors for severe maternal morbidity (SMM) in pregnant women with hypertensive disorders of pregnancy (HDP) and to develop a risk prediction model. Methods: A prospective observational cohort study was conducted among pregnant women who were hospitalized for hypertensive disorders of pregnancy (HDP) between January 2016 and December 2020 in Fujian College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Province, China (a training set), and a risk predictive model was constructed. Pregnant women with HDP who were hospitalized between January 2021 and December 2021 were selected as a validation set. Concordance index (C-index) and calibration curves were used to test predictive model discrimination and calibration. Results: We included 970 pregnant women (790 in the training set and 180 in the validation set). Least absolute shrinkage and selection operator regression was used to screen for nine related variables such as intra-uterine growth retardation (IUGR), diastolic blood pressure (DBP) and systolic blood pressure (SBP) at suspected diagnosis, total bilirubin, albumin (ALB), uric acid, total cholesterol, serum magnesium, and suspected gestational age. SBP at suspected diagnosis (OR =1.22, 95%CI:1.08-1.42) and total cholesterol (OR = 1.78, 95%CI:1.17-2.80) were independent risk factors of severe maternal morbidity in pregnant women with HDP. A nomogram was constructed, and internal validation of the nomogram model was done using the bootstrap self-sampling method. C-index in the training and the validation set was 0.798 and 0.909, respectively. Conclusion: Our prediction model can be used to determine gestational hypertension severity in pregnant women.

Experimental Study on Creep-Recovery Behavior of Polyphosphoric Acid (PPA) Modified Asphalt Binders under Multiple Factors.

The polyphosphoric acid (PPA) modified asphalt binder is a potential choice as one of the pavement materials for its excellent high-temperature performance and low cost. To further analyze the influences of temperature and load on the service life of pavement from the perspective of deformation behavior, six kinds of asphalt binders with different PPA dosages were prepared for Multiple Stress Creep and Recovery (MSCR) tests at five temperature levels. The deformation behavior is investigated by basic deformation parameters, rheological simulation, and energy parameter changes. The results show that the percent recovery (R) drops sharply while non-recoverable creep compliance (Jnr) goes up slightly with the increase in temperature. Three-element model, composed by E1, η1, and η2, can be used to describe the creep behavior. PPA-modified asphalt binder exhibits nonlinear creep behavior, and the logarithmic model can simulate recovery behavior better than the power-law model. Stored energy and dissipated energy can characterize the change of energy in the creep process under different conditions and show a significant correlation to deformation parameters. It is concluded that the elastic component of asphalt binders is increased by PPA, which is beneficial to the improvement of the deformation resistance and recovery capacity of asphalt binders. The recommended dosage of PPA is 1.5%. This investigation is conducive to a better understanding of the deformation behavior of PPA-modified asphalt binders and provides a reference for its engineering applications.

Fe3O4/ZIFs-based magnetic solid-phase extraction for the effective extraction of two precursors with diverse structures in aflatoxin B1 biosynthetic pathway.

The aflatoxin B1 (AFB1) early warning technique based on precursors is an effective strategy for the prevention of AFB1 contamination risk. The determination of precursors is imperative to ensure the efficiency of the early warning technique. Herein, a controllable magnetic adsorbent Fe3O4/ZIFs was first introduced for the effective extraction and determination of averantin (AVN) and sterigmatocystin (ST) precursors in cereal by combining magnetic solid-phase extraction (MSPE) and high-performance liquid chromatography (HPLC). Benefiting from the abundant adsorption sites and multifunctional groups matching the analytes, Fe3O4/ZIFs effectively and simultaneously extracted AVN and ST with great differences in polarity and structure via multiple interactions. AVN was extracted by Fe3O4/ZIFs mainly through π-π and hydrophobic interactions, while ST was extracted predominantly by electrostatic interactions and surface complexation. The limits of detection were 0.08 µg kg-1 (AVN) and 0.36 µg kg-1 (ST). The developed method exhibited satisfactory spiked recoveries (79.1%-105.4%) in the determination of AVN and ST in rice. This work provides a novel analytical strategy for further studying AFB1 early warning technique and the formation and transformation of aflatoxins.

Transcriptome Analysis of the Cf-13-Mediated Hypersensitive Response of Tomato to Cladosporium fulvum Infection.

Tomato leaf mold disease caused by Cladosporium fulvum (C. fulvum) is one of the most common diseases affecting greenhouse tomato production. Cf proteins can recognize corresponding AVR proteins produced by C. fulvum, and Cf genes are associated with leaf mold resistance. Given that there are many physiological races of C. fulvum and that these races rapidly mutate, resistance to common Cf genes (such as Cf-2, Cf-4, Cf-5, and Cf-9) has decreased. In the field, Ont7813 plants (carrying the Cf-13 gene) show effective resistance to C. fulvum; thus, these plants could be used as new, disease-resistant materials. To explore the mechanism of the Cf-13-mediated resistance response, transcriptome sequencing was performed on three replicates each of Ont7813 (Cf-13) and Moneymaker (MM; carrying the Cf-0 gene) at 0, 9, and 15 days after inoculation (dai) for a total of 18 samples. In total, 943 genes were differentially expressed, specifically in the Ont7813 response process as compared to the Moneymaker response process. Gene ontology (GO) classification of these 943 differentially expressed genes (DEGs) showed that GO terms, including "hydrogen peroxide metabolic process (GO_Process)", "secondary active transmembrane transporter activity (GO_Function)", and "mismatch repair complex (GO_Component)", which were the same as 11 other GO terms, were significantly enriched. An analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that many key regulatory genes of the Cf-13-mediated resistance response processes were involved in the "plant hormone signal transduction" pathway, the "plant-pathogen interaction" pathway, and the "MAPK signaling pathway-plant" pathway. Moreover, during C. fulvum infection, jasmonic acid (JA) and salicylic acid (SA) contents significantly increased in Ont7813 at the early stage. These results lay a vital foundation for further understanding the molecular mechanism of the Cf-13 gene in response to C. fulvum infection.

Numerical Simulation of the Temperature Distribution and Evolution Law of Underground Lignite Gasification.

To study the temperature distribution characteristics and evolution law of underground lignite gasifiers, a three-dimensional heat conduction model of underground lignite gasification was constructed. Moreover, the effects of different coal thicknesses, advance speeds of the flame working face, and surrounding rock types on the gasifier were analyzed. The results show that with the increase in the coal thickness, the transfer range and distance of temperature in the roof, floor, and coal seam gradually increase, as does the coal quantity in the three zones. The heat loss rate of the gasifier decreased gradually with the coal seam thickness. When the advance speed of the flame working face is 0.5 m/d, the ideal gasification coal thickness range of lignite is 2.5-17.5 m. With the increase in the gasification rate, the maximum transfer distance of temperature to the roof and floor, the average temperature of the gasifier, and the coal quantity of the three zones gradually increase. Conversely, the coal thickness corresponding to the intersection of the coal quantity of the oxidation and reduction zones and the heat loss rate of the gasifier gradually decrease. When the coal seam below 2.5 m is gasified, the gasification rate can be increased appropriately. When the coal seam is above 13 m, increasing the gasification rate will make the coal quantity in the oxidation zone close to or even higher than that in the reduction zone. Regarding the surrounding rock types comprising a combination of siltstone, mudstone, sandy mudstone, and fine sandstone, the most favorable roof and floor type for underground coal gasification is the combination of fine sandstone and sandy mudstone (without considering the sealing and mechanical properties). These results provide important theoretical support for the industrialization of underground coal gasification.

Gram-scale synthesis of nitrogen-doped carbon dots from locusts for selective determination of sunset yellow in food samples.

Locust powder was converted into water-soluble fluorescent nitrogen-doped carbon dots (N-CDs) with gram-scale yield through a self-exothermic reaction between nitric acid and diethylenetriamine (DETA) within 10 min. The morphology, elemental information, and optical properties of the N-CDs were characterized using high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared, ultraviolet-visible and fluorescence spectroscopy. Spectroscopic investigation indicated that the fluorescence emission behaviour of N-CDs is excitation wavelength dependent, with the strongest emission peak at 470 nm using a 390 nm excitation wavelength. The strong absorption peak of sunset yellow (SY) at 482 nm overlaps substantially with the blue emission peak (470 nm) of N-CDs. This enables the fluorescence emission of N-CDs to be obviously quenched by SY through the inner filter effect. There was a good linear relationship between the fluorescence quenching degree and the concentrations of SY within the range 0.5-40 µM. The detection limit of developed fluorescence assay for SY is 28 nM, and the relative standard deviation is 2.3% (c = 10 µM). The N-CDs derived from locusts by the self-exothermic reaction are highly selective and sensitive fluorescent probes for SY, which were applied to the fluorescence sensing of SY in different food samples with satisfactory results.

Porous covalent triazine-terphenyl polymer as hydrophilic-lipophilic balanced sorbent for solid phase extraction of tetracyclines in animal derived foods.

A novel hydrophilic-lipophilic balanced (HLB) solid phase extraction sorbent, microporous covalent triazine-terphenyl polymer (CTPCC-TP) was successfully synthesized and applied for the cleanup and extraction of tetracycline drugs in animal derived food samples. The specific ratio of two monomers, hydrophilic triazine and lipophilic aromatic rings, endowed the new material with hydrophilic-lipophilic balanced character, which made it capable of extracting both polar and nonpolar analytes. Prior to solid-phase extraction, food samples were extracted by McIlvaine buffer and passed through the CTPCC-TP cartridge. The experimental parameters affecting extraction efficiency, including loading, washing and elution were investigated and optimized. With the use of high-performance liquid chromatography-UV detection, a method detection limit in the range of 8.0-16.8 µg kg-1 and good linearity (22.6-1500 µg kg-1) for the determination of the tetracyclines in animal derived food samples can be achieved. The relative standard deviations (RSDs) for five replicate extractions of the tetracyclines ranged from 4.8 to 8.2%. The method recoveries for spiked tetracyclines (100 and 1000 µg kg-1) in bovine milk, egg, chicken liver samples were in the range of 81.3-98.7% with RSDs ranging from 3.9 to 7.7%, respectively, depending on both the analytes and samples. The method was suitable for the determination of tetracyclines in animal derived food samples.

Manganese-doped carbon quantum dots-based fluorescent probe for selective and sensitive sensing of 2,4,6-trinitrophenol via an inner filtering effect.

In the present work, a selective and sensitive method for detecting TNP using manganese doped carbon quantum dots (Mn-CDs) was developed. The Mn-CDs were prepared via a simple hydrothermal method using 1-(2-pyridinylazo)-2-naohthalenol naohthalenol (PAN) and MnCl2 as precursors. The as-prepared Mn-CDs have UV emission with high quantum yield (83.2%). Because of the strong characteristic absorption of TNP at 356 nm, which has good spectral overlap with the emission peak of Mn-CDs, the fluorescence intensity of Mn-CDs at 360 nm is linearly quenched in the presence of TNP in the concentration range of 0.1-200 µM. The developing assay based on an inner filter effect (IFE) mechanism for detecting TNP is selective, convenient, and shows that the as-prepared Mn-CDs have application prospects for simple and specific analytical chemistry.

Carbon dots based dual-emission silica nanoparticles as ratiometric fluorescent probe for nitrite determination in food samples.

In this work, a simple and effective strategy for designing a ratiometric fluorescent nanosensor was described. A carbon dots (CDs) based dual-emission nanosensor for nitrite was prepared by coating the CDs on to dye-doped silica nanoparticles. Dual-emission silica nanoparticles fluorescence was quenched in sulfuric acid using potassium bromate (KBrO3). The nitrite present catalyzed the KBrO3 oxidation, resulting in ratiometric fluorescence response of the dual-emission silica nanoparticles. Several important parameters affecting the performance of the nanosensor were investigated. Under optimized conditions, the limit of detection was 1.0 ng mL-1 and the linear range 10-160 ng mL-1. Furthermore, the sensor was suitable for nitrite determination in different food samples.

Carbon-dot-based dual-emission silica nanoparticles as a ratiometric fluorescent probe for vanadium(V) detection in mineral water samples.

Herein, we propose a simple and effective strategy for designing a ratiometric fluorescent nanosensor. We designed and developed a carbon dots (CDs) based dual-emission nanosensor for vanadium(V) by coating the surface of dye-doped silica nanoparticles with CDs. The fluorescence of dual-emission silica nanoparticles was quenched in acetic acid through potassium bromate (KBrO3) oxidation. V(V) could catalyze KBrO3 oxidation reaction process, resulting in the ratiometric fluorescence quenching of dual-emission silica nanoparticles. We investigated several important parameters affecting the performance of the nanosensor. Under the optimized conditions, the detection limit of this nanosensor reached 1.1ngmL-1 and the linear range from 10 to 800ngmL-1. Furthermore, we found that the sensor was suitable for determination of V(V) in different mineral water samples with satisfactory results.

Polymeric ionic liquid based on magnetic materials fabricated through layer-by-layer assembly as adsorbents for extraction of pesticides.

In this study, layer-by-layer assembly of polyelectrolyte multilayer films on magnetic silica provided a convenient and controllable way to prepare polymeric ionic liquid-based magnetic adsorbents. The resulting particles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and magnetic measurements. The data showed that the magnetic particles had more homogeneous spherical shapes with higher saturation magnetization when compared to those obtained by free radical polymerization method. This facilitated the convenient collection of magnetic particles, with higher extraction repeatability. The extraction performance of the multilayer polymeric ionic liquid-based adsorbents was evaluated by magnetic solid-phase extraction of four pesticides including quinalphos, fenthion, phoxim, and chlorpropham. The data suggested that the extraction efficiency depended on the number of layers in the film. The parameters affecting the extraction efficiency were optimized, and good linearity ranging from 2 to 250µgL-1 was obtained with correlation coefficients of 0.9994-0.9998. Moreover, the proposed method presented low limit of detection (0.5µgL-1, S/N=3) and limit of quantification (1.5µgL-1, S/N=10), and good repeatability expressed by the relative standard deviation (2.0%-4.6%, n=5). The extraction recoveries of four pesticides were found to range from 58.9% to 85.8%. The reliability of the proposed method was demonstrated by analyzing environmental water samples, and the results revealed satisfactory spiked recovery, relative standard deviation, and selectivity.

Layer-by-layer self-assembly of polyelectrolyte multilayers on silica spheres as reversed-phase/hydrophilic interaction mixed-mode stationary phases for high performance liquid chromatography.

In this study, a series of stationary phases, comprising silica spheres and polyelectrolyte multilayers (PEMs) as the core and surface coating, respectively, were prepared via a layer-by-layer self-assembly approach for use in high-performance liquid chromatography. PEMs coatings were formed by the alternate deposition of positively charged poly(allylamine hydrochloride) and negatively charged poly(ethylene-alt-maleate) anions which were synthesized by esterification between poly(ethylene-alt-maleic anhydride) and n-alkyl alcohols (CnH2n+1OH, n=4, 8, 10, 12). The chromatographic performance and retention mechanism of the new stationary phases were evaluated in simultaneous reversed-phase/hydrophilic interaction mixed-mode chromatography using different solute probes, such as alkyl benzene, p-hydroxybenzoic acid and its esters, anilines, phenols, and pyrimidines. The separation performance of the new stationary phases was optimized by tuning the n-alkyl chain length of poly(ethylene-alt-maleate) and bilayer numbers of PEMs. These results indicated that the new stationary phases demonstrate promise for the simultaneous separation of complex hydrophobic and hydrophilic samples with high selectivity.

Carbon-dot-based dual-emission silica nanoparticles as a ratiometric fluorescent probe for Bisphenol A.

A simple and effective strategy for designing a ratiometric fluorescent nanosensor is described in this work. A carbon dots (CDs) based dual-emission nanosensor for Bisphenol A (BPA) was prepared by coating CDs on the surface of dye-doped silica nanoparticles. The fluorescence of dual-emission silica nanoparticles was quenched in hydrochloric acid by potassium bromate (KBrO3) oxidation; BPA inhibited KBrO3 oxidation, resulting in the ratiometric fluorescence response of dual-emission silica nanoparticles. Several important parameters affecting the performance of the nanosensor were investigated and optimized. The detection limit of this nanosensor was 0.80ng mL-1 with a linear range from 10 to 500ng mL-1. This was applied successfully to determine BPA in the leached solution of different plastic products with satisfactory results.

Dicationic polymeric ionic-liquid-based magnetic material as an adsorbent for the magnetic solid-phase extraction of organophosphate pesticides and polycyclic aromatic hydrocarbons.

Magnetic particles modified with a dicationic polymeric ionic liquid are described as a new adsorbent in magnetic solid-phase extraction. They were obtained through the copolymerization of a 1,8-di(3-vinylimidazolium)octane-based ionic liquid with vinyl-modified SiO2 @Fe3 O4 , and were characterized by FTIR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. The modified magnetic particles are effective in the extraction of organophosphate pesticides and polycyclic aromatic hydrocarbons. Also, they can provide different extraction performance for the selected analytes including fenitrothion, parathion, fenthion, phoxim, phenanthrene, and fluoranthene, where the extraction efficiency is found to be in agreement with the hydrophobicity of analytes. Various factors influencing the extraction efficiency, such as, the amount of adsorbent, extraction, and desorption time, and type and volume of the desorption solvent, were optimized. Under the optimized conditions, a good linearity ranging from 1-100 µg/L is obtained for all analytes, except for parathion (2-200 µg/L), where the correlation coefficients varied from 0.9960 to 0.9998. The limits of detection are 0.2-0.8 µg/L, and intraday and interday relative standard deviations are 1.7-7.4% (n = 5) and 3.8-8.0% (n = 3), respectively. The magnetic solid-phase extraction combined with high-performance liquid chromatography can be applied for the detection of trace targets in real water samples with satisfactory relative recoveries and relative standard deviations.

Determination of the acid values of edible oils via FTIR spectroscopy based on the OH stretching band.

A new method for determining the acid values (AVs) of edible oils based on the OH stretching band was developed. The oil sample was diluted with carbon tetrachloride and was placed in a quartz cuvette with a thickness of 1cm to record the FTIR spectrum. The peak at 3535cm(-1), which corresponds to the OH stretch of the carboxyl group in free fatty acids, together with the peak valley at 3508cm(-1) and the spectral data in the range of 3340-3390cm(-1) were used to determine the AV of the edible oil. The excellent linear relationship between the AVs measured in this work and those measured using a titration method, with a correlation coefficient (R) of 0.9929, indicates that the present procedure can be applied as an alternative to the classic method for determining the AVs of edible oils.

Polyelectrolyte multilayers on magnetic silica as a new sorbent for the separation of trace copper in food samples and determination by flame atomic absorption spectrometry.

A novel magnetic silica sorbent with polyelectrolyte multilayers (PEMs) on its surface was prepared, and the sorbent was used for the magnetic solid phase extraction (MSPE) of trace Cu(2+) in drinking water with flame atomic absorption spectrometry (FAAS) as the detector. The experimental parameters for the MSPE procedure, such as the pH, desorption conditions, ultrasonic time and co-existing ions effects, were investigated. The adsorption capacity of the new sorbent was 14.7 mg g(-1) for Cu(2+). The detection limit of the developed method was 0.23 ng mL(-1) for Cu(2+) with an enrichment factor of 95.7. The analytical data obtained from the certified reference water and rice samples were in good agreement with the certified values. This method was also successfully applied to the determination of trace Cu(2+) in different food samples with satisfactory results.

Poly(ionic liquid) immobilized magnetic nanoparticles as new adsorbent for extraction and enrichment of organophosphorus pesticides from tea drinks.

New poly(ionic liquid) immobilized magnetic nanoparticles (PIL-MNPs) were synthesized via co-polymerization of 1-vinyl-3-hexylimidazolium-based ionic liquid and vinyl-modified magnetic particles and were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and magnetic measurements. The PIL-MNPs were utilized as adsorbent phases in magnetic solid-phase extraction (MSPE). The extraction and enrichment efficiency were evaluated by using four organophosphorus pesticides (parathion, fenthion, phoxim and temephos) as test analytes. Various parameters, such as amount of adsorbent, adsorption time, desorption solvent and time, and ionic strength were investigated. The proposed method showed good linearity for the analytes in the concentration range of 1-200µgL(-1) with a correlation coefficient (R)>0.9963. Low limit of detection of 0.01µgL(-1) and high enrichment factors ranging from 84 to 161 were achieved. The proposed method has been successfully used to determine organophosphorus pesticides from three tea drink samples with satisfactory recovery of 81.4-112.6% and RSDs of 4.5-11.3%. The PIL-MNP adsorbent can be reused for 20 times without a noticeable decrease in extraction efficiency.

Macrocyclic polyamine-functionalized silica as a solid-phase extraction material coupled with ionic liquid dispersive liquid-liquid extraction for the enrichment of polycyclic aromatic hydrocarbons.

In this study, silica modified with a 30-membered macrocyclic polyamine was synthesized and first used as an adsorbent material in SPE. The SPE was further combined with ionic liquid (IL) dispersive liquid-liquid microextraction (DLLME). Five polycyclic aromatic hydrocarbons were employed as model analytes to evaluate the extraction procedure and were determined by HPLC combined with UV/Vis detection. Acetone was used as the elution solvent in SPE as well as the dispersive solvent in DLLME. The enrichment of analytes was achieved using the 1,3-dibutylimidazolium bis[(trifluoromethyl)sulfonyl]imide IL/acetone/water system. Experimental conditions for the overall macrocycle-SPE-IL-DLLME method, such as the amount of adsorbent, sample solution volume, sample solution pH, type of elution solvent as well as addition of salt, were studied and optimized. The developed method could be successfully applied to the analysis of four real water samples. The macrocyclic polyamine offered higher extraction efficiency for analytes compared with commercially available C18 cartridge, and the developed method provided higher enrichment factors (2768-5409) for model analytes compared with the single DLLME. Good linearity with the correlation coefficients ranging from 0.9983 to 0.9999 and LODs as low as 0.002 µg/L were obtained in the proposed method.

Two new azamacrocycle-based stationary phases for high-performance liquid chromatography: preparation and comparative evaluation.

In this paper, two new azamacrocycle-bonded stationary phases for high-performance liquid chromatography are described. The new phases were prepared by respectively coupling a 14-membered Curtis macrocycle and a 30-membered hexaazaannulene to γ-chloropropyltrimethoxylsilane-modified silica and characterized by elemental analysis and infrared spectroscopy. To understand the effects of the structures of the azamacrocyles and their functional groups upon the retention and separation, the chromatographic behaviors of the two stationary phases were compared by eluting alkylbenzenes, polycyclic aromatic hydrocarbons (PAHs) and aromatic amines. The two new phases demonstrated unique selectivity and fine chromatographic performance, which were guaranteed by multiple interactions, including hydrophobic, hydrogen-bonding, π-π and dipole-induced dipole interactions between stationary phase and solutes. On the other hand, the difference between the structures of embedded azamacrocyles did lead to remarkable dissimilarity in the shape and planarity recognition of isomers, which was highlighted by the 30-membered hexaazaannulene-bonded phases' superiority over 14-membered tetraazamacrocycle-bonded phases' in discriminating specific PAHs. With a wide range of probes, the linear solvation energy relationship model was also applied to evaluate the chromatographic properties of the two stationary phases, further verifying the chromatographic results.

A new 14-membered tetraazamacrocycle-bonded silica stationary phase for reversed-phase high-performance liquid chromatography.

A new high-performance liquid chromatography stationary phase has been prepared by covalently bonding 14-membered tetraazamacrocycle to silica gel using γ-chloropropyltrimethoxylsilane as coupling agent. The structure of the new material was characterized by infrared spectroscopy and elemental analysis. With 32 solutes including aromatic and aliphatic compounds, the linear solvation energy relationship method was successfully used to chromatographically evaluate the new phase in reversed phase mode. The retention property of the new phase shows evident similarity with that of ODS stationary phase, as well as distinctive, unique retention characteristics. The separations of n-alkylbenzene, carbamate and organophosphorus pesticides with diversified functional groups as well as phenolic compounds demonstrate that in addition to hydrophobic interaction, dipole-dipole interaction and hydrogen bonding interaction plus acid-base equilibrium could also be simultaneously offered by this new stationary phase, as a result excellent chromatographic performances are guaranteed.