Search

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent pollutants that are widely distributed in the environment. Due to their stable structure and poor degradability, PAHs exhibit carcinogenic, teratogenic, and mutagenic toxicity to the ecological environment and organisms, thus increasing attentions have been paid to their removals and remediation. Green, safe and economical technologies are widely used in the bioremediation of PAHs-contaminated soil. This article summarizes the present status of PAHs pollution in soil of China from the aspects of origin, migration, fate, and pollution level. Meanwhile, the types of microorganisms and plants capable of degrading PAHs, as well as the underlying mechanisms, are summarized. The features of three major bioremediation technologies, i.e., microbial remediation, phytoremediation, and joint remediation, are compared. Analysis of the interaction mechanisms between plants and microorganisms, selection and cultivation of stress-resistant strains and plants, as well as safety and efficacy evaluation of practical applications, are expected to become future directions in this field.

Whether the general belief in a just world (GBJW) can protect individual emotions during a major disaster is a matter of debate. This study conducted two experiments to explore this question during the COVID-19 epidemic. Experiment 1 (N = 92, Mage = 22.52, 48.91% was male) manipulated the focus regarding the COVID-19 epidemic to investigate the impact of this focus on participants' emotions. The results showed that compared with the nonepidemic focus group, the epidemic focus group had higher negative emotions and lower positive emotions. Experiment 2 (N = 200, Mage = 23.91, 49% was male) manipulated the epidemic focus and GBJW to investigate their effects on the participants' emotions. The results showed that high levels of GBJW reduced negative emotions and increased positive emotions regardless of whether the participants were focused on the epidemic. This study expands the influence of the GBJW on individual emotions and finds that the GBJW can protect individuals' emotions when they face a major social disaster. These findings imply that controlling people's intake of information on the epidemic can avoid their suffering from the vicarious traumatization caused by epidemic-related information overload and that improving the public's GBJW protects their mental health during an epidemic.

Imidacloprid (IMI) is one of the most frequently used neonicotinoid insecticides, but recent studies have shown adverse effects on mammals. IMI was found to be neurotoxic and hepatotoxic. In the present study, the effects of repeated oral administration of two doses of IMI (5 and 20 mg/kg/day) for 28 days on hippocampus and liver of female KM mice were studied. The histopathological and biochemical experiments indicated obvious damages to the hippocampus and liver of mice in the high-dose group (20 mg/kg/day). Using a high-throughput metabolomics platform based on ultrahigh performance liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS), we studied effects of IMI on metabolic profiles in the hippocampus and liver of mice. Significant differences among the control group, the low-dose group and the high-dose group were clearly presented using multivariate analysis. The changed metabolic profile in the low-dose group (5 mg/kg/day) revealed that the metabolic disturbance in the hippocampus and liver of mice had been induced by low-dose of IMI, although no significant histopathological changes were observed in the low-dose group. Six differential metabolites in the hippocampus and 10 differential metabolites in the liver were identified as the possible biomarkers to distinguish IMI exposure from the control group using the variable importance in projection (VIP) value and receiver operating characteristic (ROC) analysis. The metabolism disturbances of important biochemical pathways in the hippocampus and liver of mice in the exposed groups were elucidated, mostly concentrated in lipid metabolism, amino acid metabolism, nucleotide metabolism, carbohydrate metabolism, and energy metabolism (p

Neonicotinoid insecticides are the most widely used insecticides in the world. However, some experiments in vivo and vitro have shown association between neonicotinoids exposure and adverse effects in non-target mammals. The aims of this study were to 1) develop a robust method for simultaneous quantification of urinary neonicotinoids with a wide water solubility range by modified solid-phase extraction–ultrahigh performance liquid chromatography– tandem mass spectrometry and 2) quantify the concentrations of ten neonicotinoids in 386 adolescents in Chongqing of Southwest China by using the developed method and assess health risks of exposure to neonicotinoids. The introduction of extractive crystallization effectively removed interfering inorganic salts and improved the sensitivity of the method. The mean recoveries of all the analytes were satisfactory in the range of 89.1–104.8% and the limits of detection ranged from 0.001 to 0.02 ng/mL. The developed method was sensitive, accurate and suitable for trace detection and batch analysis in biomonitoring-based studies. Of the ten examined neonicotinoids, acetamiprid had the highest geometric mean concentration (49.43 μg/g creatinine), followed by clothianidin (5.01), imidacloprid (3.80), thiamethoxam (3.24), thiacloprid (2.25), nitenpyram (1.79), dinotefuran (1.76), sulfoxaflor (1.65), imidaclothiz (1.28) and flonicamid (1.01). High detection rates of neonicotinoids (79.3–100.0%) indicated a ubiquitous adolescents’ exposure to neonicotinoids in urban areas of Chongqing. Nevertheless, hazard quotient and hazard index data exhibited a low health risk caused by the individual and cumulative exposure to neonicotinoids on the basis of the reference limit values recommended by the U.S. Environmental Protection Agency and the National Food Safety Standard of China.

As an important newly Food and Drug Administration (FDA)-approved drug for treating diabetes, rosiglitazone (1) has received much attention from researchers in many areas. To search for an economical and convenient synthesis method for 1, we explored the reaction conditions and workup of a scalable five-step synthetic route by an orthogonal method to determine the best condition for each reaction step. The starting materials are commercially available, including 2-chloropyridine (2), N-methylethanolamine (3), 4-fluorobenzaldehyde (4a) or 4-hydroxybenzaldehyde (4b), and 1,3-thiazolidine-2,4-dione (5). The five sequential reaction steps are cyclization, alkylation, etherification, condensation, and reduction, having optimal yield of 90, 99, 59, 75, and 91 %, respectively. The best overall yield to synthesize rosiglitazone based on compound 2 was 40 %, being suitable for industrial purposes, using water as a green solvent and avoiding column chromatography during the last three reaction steps.

A series of 2,3-substituted-2-iminothiazoline-4-ones derivatives have been synthesized via an improved method including an auto-catalyzed reaction. This method avoided using any extra catalyst except for the reaction material. This method has been successful in both the aromatic substituted 2-iminothiazolines and the alkyl substituted 2-iminothiazolines. The special product with a hydroxyl group on the 2-iminogroup of 1,3-thiazoline-4-ones has also been obtained unexpectedly. The possible mechanism has been proposed for the special process of dealkylation and hydroxylation. This method offered a special way to afford the 2-hydroxyimino-substituted thiazoline-4-one derivatives in an efficient and eco-friendly way. The mechanism of the transformation under acid condition has also been proposed.

To search for an economical and convenient synthesis of sunitinib and its malate salt, optimization of a scalable synthetic route was explored by designing a standard experimental protocol on laboratory scale using commercially available materials including acetyl ethyl acetate, 4-fluoroaniline, and N 1,N 1-diethylethane-1,2-diamine. The optimal conditions were established based on investigating the main reaction steps, including cyclization, hydrolysis, decarboxylation, formylation, and condensation, giving optimized yields for each step of 94.4, 97.6, 98.5, 97.1, 91.0, 86.3, 85.5, 88.2, 99.1, 97.3, and 58.7 %, respectively. The synthesis process of 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid as the important intermediate was significantly improved by using solvent-free decarboxylation instead of the traditional process in a high-boiling-point solvent. The subsequent formylation was conducted directly using the dichloromethane solution of the crude product from decarboxylation, leading to an almost quantitative combined yield of these two steps. The overall yields of sunitinib and its salt using the optimal synthesis process were 67.3 and 40.0 % based on acetyl ethyl acetate. The obtained data could be used as reference for future industrialization, especially for avoiding expensive solvents and reducing reaction time.

A simple, selective, and sensitive electrochemical sensor for detecting dopamine (DA) using a copper oxide (CuO) nanoleaf electrode as an active platform was developed in this work. The CuO nanoleaf electrode was fabricated via one-step chemical oxidation of copper foil immersed in an alkaline solution with a strong oxidant. The electrode exhibits selective and sensitive DA detection in the presence of ascorbic acid and uric acid in phosphate buffered saline (pH 8.0). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were conducted to test the electrochemical behaviour of DA in the CuO nanoleaf electrode. DPV anodic peak currents at approximately 0.20 V were enhanced by increasing DA concentrations. The developed electrochemical sensor presents two linear ranges of 1 μM to 7.5 μM and 7.5 μM to 140 μM, respectively. And the detection limit of the proposed method is 0.5 μM for DA. Applying the CuO nanoleaf electrode in actual determination of DA injection yields accurate results. Furthermore, the analytical results of DA in serum show that the developed method is a promising alternative approach for complex systems.

A series of 2,3-substituted-2-iminothiazoline-4-ones derivatives have been synthesized via an improved method including an auto-catalyzed reaction. This method avoided using any extra catalyst except for the reaction material. This method has been successful in both the aromatic substituted 2-iminothiazolines and the alkyl substituted 2-iminothiazolines. The special product with a hydroxyl group on the 2-iminogroup of 1,3-thiazoline-4-ones has also been obtained unexpectedly. The possible mechanism has been proposed for the special process of dealkylation and hydroxylation. This method offered a special way to afford the 2-hydroxyimino-substituted thiazoline-4-one derivatives in an efficient and eco-friendly way. The mechanism of the transformation under acid condition has also been proposed.

A new series of 2-substituted imino-3-substituted-5- heteroarylidene-1,3-thiazolidine-4-ones as the potent bidentate PTP1B inhibitors were designed and synthesized in this paper. All of the new compounds were characterized and identified by spectra analysis. The biological screening test against PTP1B showed that some of these compounds have the positive inhibitory activity against PTP1B. The activity of the compounds with 5-substituted pyrrole on 5-postion of 1,3-thiazolidine-4-one are more potent than that of those compounds with 5-substituted pyridine group. Compound 14b, 14h and 14i showed IC50 values of 8.66 μM, 6.83 μM and 6.09 μM against PTP1B, respectively. Docking analysis of these active compounds with PTP1B showed the possible interaction modes of these biheterocyclic compounds with the active sites of PTP1B. The inhibition tests against oncogenetic CDC25B were also conducted on this set of compounds to evaluate the selectivity and possible anti-neoplastic activity. Compound 14b also showed the lowest IC50 of 1.66 μM against CDC25B among all the possible inhibitors, including 14g, 14h, 14i and 15c. Some pharmacological parameters including VolSurf, steric and electric descriptors of all the compounds were calculated to give some hints about the relative relationship with the biological activity. The result of this study might give some light on designing the possible anti-cancer drugs targeting at phosphatases. The most active compound 14i might be used as the lead compound for further structure modification of the new low molecular weight PTP1B inhibitors with the N-containing heterocyclic skeleton.

2,4-Dimethylpyrrole (1) is a very important intermediate in the synthesis of fluorescent molecules (such as BODIPY), 1 , 2 the new tyrosine kinase inhibitor (such as sunitinib), 3 – 5 anti-inflamma...

Thiourea nitrate (TN) was easily prepared from thiourea and nitric acid to explore its use as a new nitration reagent. Nitrations of various aromatic compounds utilizing TN in concentrated sulfuric acid were studied. TN could convert aromatic compounds to the corresponding nitrated derivatives with various abnormal yields under mild conditions. The results suggested that the reaction mechanism might be different from those of traditional nitration reagents.

Functionalized 2-thiazolidin-4-ones are important heterocyclic compounds owing to their biological activities, 1 , 2 such as anti-tuberculosis, 3 anti-convulsant, 4 fungistatic, 5 bacteriostatic, 6...

In this paper, we study the existence of periodic solutions of second-order impulsive differential equations at resonance. We prove the existence of periodic solutions under a generalized Landesman-Lazer type condition by using the variational method. The impulses can generate a periodic solution.

Thiourea nitrate (TN) was easily prepared from thiourea and nitric acid to explore its use as a new nitration reagent. Nitrations of various aromatic compounds utilizing TN in concentrated sulfuric acid were studied. TN could convert aromatic compounds to the corresponding nitrated derivatives with various abnormal yields under mild conditions. The results suggested that the reaction mechanism might be different from those of traditional nitration reagents.

The presence of the LH receptor (LHR) in nongonadal tissues of the reproductive tract has been reported, but localization studies have not been performed. Our objectives were to demonstrate the presence of LHR in the reproductive tract and to localize receptor expression. Reproductive age rats and mice were obtained and 125 I-hCG binding assays were performed on membrane preparations from the uterus, ovary, liver, and testis. In situ hybridizations were performed using 35 S-labeled antisense and sense RNA probes prepared from nucleotides 1‐591 of the mouse LHR cDNA. Specific hCG binding was detected in membrane preparations from the ovary, uterus, and testis but not in the liver in both the rat and mouse. In the ovary, LHR mRNA was localized in theca cells, large follicles, and corpora lutea as expected. In the uterus, LHR mRNA was expressed in stromal cells of the endometrium and in the uterine serosa. Uterine smooth muscle cells had low levels of expression, and the endometrial epithelium was negative. In the oviduct, high levels of LHR expression were noted on the serosa and in subepithelial cells. Oviductal smooth muscle had low expression, and the epithelium was negative. We conclude that functional, nongonadal LHR are expressed in the mouse reproductive tract. The presence and localization of LHR expression in the mouse reproductive tract lay the foundation for transgenic models to address the physiologic role of these receptors. fallopian tubes, female reproductive tract, hormone action, LH

Functionalized 2-thiazolidin-4-ones are important heterocyclic compounds owing to their biological activities, 1 , 2 such as anti-tuberculosis, 3 anti-convulsant, 4 fungistatic, 5 bacteriostatic, 6...

2,4-Dimethylpyrrole (1) is a very important intermediate in the synthesis of fluorescent molecules (such as BODIPY), 1 , 2 the new tyrosine kinase inhibitor (such as sunitinib), 3 – 5 anti-inflamma...

In this paper, some sufficient conditions on the existence of $2k\pi$ -periodic solutions for a kind of prescribed mean curvature Rayleigh equations are given. Then the existence of nontrivial homoclinic solutions for prescribed mean curvature Rayleigh equations is obtained.