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Aim: The rising prevalence of periodontitis imposes substantial burdens on individuals and society. Identifying environmental risk factors for periodontitis may contribute to tackling the global public health burden of it. This study aimed to assess the association between long‐term exposure to PM2.5 and periodontitis in a nationally representative population from China. Materials and Methods: In this multi‐centre cross‐sectional study of 372 communities in 31 provinces of Mainland China, we used data from the Fourth National Oral Health Survey of China in 2015–2016, in combination with high‐resolution gridded concentrations of fine particulate matter (PM2.5). Logistic regression was applied to assess the relationship between long‐term PM2.5 exposure and the risk of periodontitis. In addition, we examined whether the association varied by individual characteristics, and estimated the exposure–response relationship and the risk of damaged tooth in each tooth quadrant. Results: A total of 8391 participants from 96 cities were diagnosed with periodontitis, accounting for 60.04% (8391/13,459) of the participants. For each 10 μg/m3 increment in 1‐, 3‐ and 5‐year average concentrations of PM2.5, the risk of total periodontitis increased by 9.0% (95% confidence interval: 6.0%, 12.0%), 8.0% (6.0, 11·0) and 7.0% (5.0, 10.0), respectively. Mild periodontitis was more strongly associated with PM2.5 exposure than moderate and severe periodontitis. The teeth in the lower anterior, lower posterior or upper anterior are more susceptible to the effect of PM2.5 on the periodontal pocket, calculus and bleeding gums. Conclusions: Long‐term exposure to PM2.5 is significantly associated with an increased risk of periodontitis in the nationally representative Chinese population. Considering the rising prevalence of periodontitis, considerable costs of treatment, and substantially adverse effects on individuals and society, these findings suggest that stricter air quality regulations may help ease the burden of periodontal disease. [ABSTRACT FROM AUTHOR]

Aim: To explore the epidemiology of plaque‐induced gingivitis and related factors among Chinese adolescents. Materials and Methods: This cross‐sectional survey comprised 118,601 schoolchildren in the 12–15‐year age group. Data came from the National Oral Health Survey in mainland China. The field investigation was conducted according to the World Health Organization guidelines. The new 2018 case definition for plaque‐induced gingivitis was used. Participants underwent clinical examinations and completed a structured questionnaire. Bleeding on probing (BOP) was performed on all teeth. Multinomial logistic regression was used to explore the factors related to the extent of gingivitis. Results: Nearly half of the study population (47.3%) had plaque‐induced gingivitis; 23.9% and 23.3% presented with localised and generalised gingivitis, respectively. The first molars were the most affected by BOP. Well‐established factors, such as demographic characteristics, socioeconomic status, local factors and smoking habits, were significantly associated with the extent of gingivitis. Odds ratios for localised and generalised gingivitis increased with the decrease in frequency of toothbrushing with a fluoride dentifrice. Conclusions: The study population had high plaque‐induced gingivitis prevalence. The extent of gingivitis appeared to have a dose–response relationship with the frequency of toothbrushing with a fluoride dentifrice. [ABSTRACT FROM AUTHOR]

BACKGROUND: Citrus leaf miners are a common pest harming citrus production and quality during citrus planting. During the citrus plant's growth phase, bisultap formulation was frequently used to boost yield and produce fruit of high quality. However, research on citrus's dietary risk assessment for bisultap residues, dissipation and residues is lacking. RESULTS: Liquid chromatography‐tandem mass spectrometry was used to develop an accurate and sensitive analytical method for derivatizing bisultap into nereistoxin in whole fruit, pulp and peel. At various levels of addition, the mean recovery of bisultap ranged from 84.64% to 111.09% with a reasonable relative RSD (< 20%). The half‐lives in Guangxi and Guizhou were 3.96 and 6.03 days, respectively. After 14–21 days of bisultap application, total residues (bisultap and its metabolite nereistoxin) in the whole fruit were from < 0.02 to 0.228 mg kg−1 in the four experiment sites. Total residue (bisultap and nereistoxin, expressed by bisultap) in whole fruit was approximately 1.05–7.23 times that of pulp. The washing process with tap water removed 85.71% to 98.78% of the bisultap residue in the whole fruit. Bisultap's risk assessment value in citrus was in the range 0.16–1.28%. CONCLUSION: In the whole citrus fruit, bisultap degrades rapidly. Bisultap residues primarily accumulate on citrus peels, and so washing and peeling citrus may effectively remove bisultap residues. For various age groups, the chronic dietary risk of bisultap was acceptable. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Understanding pesticide penetration behavior is important for effective application of pesticides. However, there is a lack of an effective method to monitor pesticide penetration behavior and its changing process. In the present study, a novel surface‐enhanced Raman scattering (SERS) mapping method was used for real‐time and in situ tracking of the penetration behaviors of thiram and thiram–organosilicon mixture on cabbage leaves. RESULTS: The results suggest that thiram has very weak ability to penetrate into cabbage leaves. However, when the thiram–organosilicon mixture was placed on leaf surfaces, a clear thiram signal was detected inside the leaf after 2 h of exposure, a strong signal was observed after 12 h, and the penetration depth of thiram was approximately 200 μm after 48 h. CONCLUSION: SERS mapping was demonstrated to be a reliable method for in situ monitoring of organosilicon‐induced thiram penetration into cabbage leaf over time. The present study provides a new reference for rationally selecting adjuvants, effectively applying pesticides, and reducing pesticides residue in food. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: In our previous work, we applied a new synthetic strategy to design and synthesize a series of imidazopyridine mesoionic derivatives with an ester group. The newly synthesized compounds had excellent insecticidal activity against aphids; however, insecticidal activity against planthoppers was less than satisfactory. In the present study, we designed and synthesized a series of novel imidazopyridine mesoionic compounds, containing an amido group, and these compounds were found to have improved insecticidal activity against planthoppers. RESULTS: The bioassay results demonstrated that most of the target compounds had moderate‐to‐good insecticidal activity against Sogatella furcifera, and some exhibited good‐to‐excellent insecticidal activity against Aphis craccivora. Among them, compound C6 had the highest insecticidal activity against S. furcifera and A. craccivora, with LC50 values of 10.5 and 2.09 μg mL−1, respectively. Proteomic results suggested that the differentially expressed proteins mainly were enriched in the nervous system‐related pathways after compound C6 treatment. Enzymatic assay results showed that compound C6 and triflumezopyrim had a certain inhibitory effect on acetylcholinesterase. Molecular docking and real‐time quantitative PCR results indicated that compound C6 not only may act on the nicotinic acetylcholine receptor, but also may interact with the α4 and β1 subunits of this receptor. CONCLUSION: The results reported here contribute to the development of new mesoionic insecticides and further our understanding of the mode‐of‐action of imidazopyridine mesoionic derivatives. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Plant virus diseases are difficult to control and severely threaten the productivity of crops, which leads to huge financial losses. To discover the new antiviral drugs, 34 novel ferulic acid derivatives with piperazine moiety were synthesized, and the antiviral activities were systematically screened as well. Results: Bioassay results indicated that most of the target compounds had outstanding antiviral activities against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) in vivo. In particular, compound E2 exhibited remarkable curative activities to TMV and CMV with EC50 values of 189.0 and 401.7 μg/mL compared to those for ningnanmycin (387.0, 519.3 μg/mL) and ribavirin (542.1, 721.5 μg/mL). And then the mechanisms of compound E2 were studied by chlorophyll content, differentially expressed proteins and genes tests. Conclusion: The excellent antiviral activity of compound E2 was closely associated with the increase in host photosynthesis, which was confirmed by chlorophyll content, differentially expressed proteins and genes assays. Compound E2 can be considered as a lead structure for the discovery of new antiviral agents. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to investigate socioeconomic‐related inequality in dental care service utilization in the past 12 months among Chinese preschool children and to explore the contribution of various factors to this inequality. Method: A total of 40 305 children aged 3‐5 years from 372 kindergartens who participated in the Fourth National Oral Health Survey in China were included in the final analysis. The method of data weighting in complex sampling was adopted to make the samples more representative. Erreygers‐corrected concentration index (EI) was used to measure socioeconomic‐related inequality in dental care service utilization. The horizontal inequality index (HI) was employed to analyse horizontal inequality. Decomposition analyses were conducted to explore the contributions of income level, need variables (dmft, caregiver‐evaluated oral health status and toothache experience) and nonneed variables (caregiver education level, residential location, age, and sex) to the inequality of health service utilization. Result: The utilization of oral health services within the past 12 months among the high‐, middle‐ and low‐income groups was 17.4% (95% CI: 15.6‐19.3), 13.6% (95% CI: 12.2‐15.1) and 9.4% (95% CI: 8.1‐11.0) respectively. The concentration curve was below the line of equality, and the EI and HI were 0.072 and 0.078, respectively, indicating that dental care utilization in children aged 3‐5 years was concentrated in those who were better off. The contribution of the need variables to socioeconomic‐related inequality in dental services was minimal, and most dental care utilization inequality could be explained by household income, caregiver education attainment and urban‐rural disparities, accounting for 32.0%, 49.4% and 20.4% respectively. Conclusion: This study reveals the existence of pro‐rich inequality in dental care utilization among preschool children in China. The decomposition analysis suggests that income, caregiver education background and urban‐rural disparities are the main factors contributing to this outcome. Equity‐oriented policies and programmes are needed to achieve equitable dental care utilization. [ABSTRACT FROM AUTHOR]

BACKGROUND Pesticide residues in agricultural products and foods pose a serious threat to human health, and therefore a simple, rapid and direct method is urgently needed for pesticide residue detection. In addition to realizing the detection of acetamiprid in cabbage extract solution, the main target of this study was to establish an in situ surface‐enhanced Raman scattering (SERS) method, which could directly detect acetamiprid residue on cabbage leaf without the need for extraction. Acetamiprid was first used to contaminate the surface of fresh cabbage leaf, and then bimetallic silver‐coated gold nanoparticles (Au@AgNPs) were added on the contaminated spots and dried for SERS measurement. RESULTS: Results suggested that acetamiprid can be detected in cabbage extract and on cabbage leaf surface in situ using the SERS method based on the Au@AgNPs substrate. The limit of detection was 0.08 μg mL−1 in cabbage extract and 0.14 mg kg−1 on cabbage leaf, the recovery ranged from 80.5% to 105.5% and the relative standard deviation was in the range 4.37–10.63%. CONCLUSIONS: The proposed SERS method provides an in situ, nondestructive and rapid way to detect acetamiprid residue on the surface of fruits and vegetables, which could serve as an auxiliary approach for early screening of contaminated produce in field or on site in the future. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This study established and validated a simple and sensitive analytical approach for determining pinoxaden residues in soil. The dissipation and adsorption–desorption of pinoxaden in four kinds of Chinese soil were comprehensively investigated for the first time, and the possible metabolic products and pathways were identified. The developed method was successfully applied in dissipation and adsorption–desorption trials. Several influential factors, including temperature, organic matter, and moisture content, affected the dissipation rate of pinoxaden in soil. During the dissipation process, 1 hydrolytic intermediate and 13 possible transformation products were identified, and predicted metabolic pathways were composed of electron rearrangement, oxidation, cyclization, carboxylation, and so on. Both the adsorption and desorption isotherms of pinoxaden in four kinds of Chinese soil followed the Freundlich equation, and the Freundlich Kf values were positively correlated with the soil cation exchange capacity. According to the calculated Gibbs free energies, the adsorption of pinoxaden was an endothermic reaction and mainly a physical process. These results could provide some useful data for the determination of pinoxaden in other matrices and the evaluation of the environmental fate of pinoxaden in soil and other ecosystems. [ABSTRACT FROM AUTHOR]

A series of novel mandelic acid derivatives containing a 1,3,4‐oxadiazothioether moiety were designed and synthesized. Bioassay results showed that some target compounds exhibited certain antifungal activity against six kinds of pathogenic fungi in vitro. Among the compounds, the EC50 values of T41 against Gibberella saubinetii, Verticillium dahlia and Sclerotinia sclerotiorum were 31.0, 27.0 and 32.1 μg/ml, respectively, and the EC50 value of T14 against S. sclerotiorum was 14.7 μg/ml. The antifungal activity against the resistant fungus S. sclerotiorum indicated that this series of target compounds may have the similar action modes or sites as the commercialized succinate dehydrogenase inhibitor carboxin. A morphological study with fluorescence microscope demonstrated that T41 can significantly destroy the membrane integrity of G. saubinetii. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bananas are vulnerable to disease and insect pests after producing fruit. In order to increase the yield and produce high‐quality fruit, the insecticides and fungicides are mixed and applied 2–3 times on banana, then the fruit is bagged. Buprofezin, imidacloprid, difenoconazole, and pyraclostrobin are widely used on banana. However, there is a lack of research on the effect of fruit bagging on pesticide dissipation and residues on bananas. RESULTS: A versatile liquid chromatography–tandem mass spectrometry method with modified QuEChERS sample preparation has been developed for the determination of buprofezin, imidacloprid, difenoconazole, and pyraclostrobin in bananas. The recovery of four pesticides was satisfactory (74.96–98.63%) with reasonable relative standard deviation (≤ 8.78%). In Hainan and Guangzhou, the half‐lives of the four pesticides were 4.68–13.9 and 5.63–20.4 days in non‐bagged and bagged bananas, respectively. The significance analysis of the half‐lives in the two sites showed that the dissipation rates of the three pesticides (imidacloprid, difenoconazole, pyraclostrobin) on whole bananas were significantly decreased by the effect of bagging (P < 0.05). However, there was no significant difference in the degradation of half‐life of buprofezin under bagging and without bagging (P > 0.05). CONCLUSION: The high vapor pressure and the non‐systemic property cause buprofezin to evaporate and dissipate the fastest among the four studied pesticides. The ultimate residues of four pesticides in bananas are lower than the maximum residue limits in China after three times of mixed applications under bagging or non‐bagging. The results provide scientific data for evaluating the safety of four pesticides in banana bagging. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Enantioselective degradation behavior of mandipropamid, and factors affecting its degradation and metabolites in four types of Chinese soil were investigated in this work. The results showed that the enantiomeric selectivity values ranged from 0.025 to 0.170, indicating that enantioselectivity was found in the degradation process of the racemate in all of the soil samples and that the R‐(−)‐enantiomer was preferentially degraded. The degradation compounds formed faster in native alkaline soils (half‐lives = 35.5–39.80 d) than in native acidic soils (half‐lives = 51.3–77.90 d). The half‐lives of the R‐(−)‐enantiomer and S‐(+)‐enantiomer were 35.5–73.7 and 37.5–77.9 d, 66.6–97.6 and 70.0–103.5 d, and 52.5–110.0 and 66.0–144.4 d in the four types of soil under native, sterilized, and organic matter‐removed conditions, respectively, which indicated that mandipropamid degradation can be attributed to microbial activity and the organic matter content in the soil. Furthermore, the half‐lives of the R‐(−)‐enantiomer and S‐(+)‐enantiomer decreased 1.07–1.95 and 1.08–1.79 times with each 10 °C increase in incubation temperature, and the half‐lives of the R‐(−)‐enantiomer and S‐(+)‐enantiomer decreased 1.09–1.43 and 1.06–1.50 times with increasing moisture content. However, the incubation temperature and soil moisture did not change the enantioselectivity. Mandipropamid enantiomers were observed to be configurationally stable in the selected soil, and no interconversion was found during the incubation of enantiopure R‐(−)‐mandipropamid or S‐(+)‐mandipropamid in native or sterilized soil. During the degradation process, four major metabolites were detected. In comprehensive consideration of the environmental behavior, the enantioselective degradation results should be considered to more accurately assess the risk of this chiral pesticide in a real environment. Core Ideas: Enantioselectivity of mandipropamid in Chinese soil was first reported.R‐mandipropamid showed a preferential degradation.Enantiopure enantiomers were configurationally stable.Microbial, pH, organic matter, temperature, and moisture influenced degradation.Four major metabolites of mandipropamid were found in Chinese soil. [ABSTRACT FROM AUTHOR]

Aim: To evaluate periodontal conditions in adults in mainland China based on data from the 4th National Oral Health Survey. Materials and methods: Data of adult subjects (35‐ to 44‐year‐old group [N = 4409], 55‐ to 64‐year‐old group [N = 4622], and 65‐ to 74‐year‐old group [N = 4428]) were analysed. Demographic, socio‐economic, personal habit, dental history, and health attitude data were obtained using a questionnaire. Periodontal condition was assessed using the standardized case definitions of the 2018 classification scheme. A multivariate analysis was performed to investigate the relationship between periodontitis severity and age, smoking status, gender, and region using generalized additive models after adjusting for confounders. Results: The frequency of subjects with periodontitis was 52.8%, 69.3%, and 64.6% in the three age groups, respectively. The frequency of subjects with severe periodontitis (stage III or IV) was 10.6%, 37.3%, and 43.5% in the three age groups, respectively. The severity of periodontal disease was positively associated with age. Current and former smokers exhibited significantly greater disease severity than non‐smokers after adjustment for confounders. No significant difference of severity was found between males and females. Conclusion: Within the limitations of the study, the prevalence of periodontitis is very high among adults in mainland China. Periodontal status is associated with age and smoking status. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to measure socioeconomic‐related inequality and horizontal inequity in the use of oral health services and decompose this inequality among adults of different age groups in China. Methods: In total, 10 973 adults (3669 aged 35‐44 years, 3767 aged 55‐64 years and 3537 aged 65‐74 years) who participated in the 4th National Oral Health Survey (2015‐2016) in China were included. Concentration curves and the Erreygers‐corrected concentration index (EI) were employed to measure socioeconomic‐related inequality in the use of oral health services. Then, inequity in this utilization was measured by the horizontal inequity index (HI). Furthermore, decomposition analyses were conducted for the three groups to explain the contributions of income level, need factors (ie self‐assessed oral health and evaluated oral health status), other factors (ie sex, residential location, educational attainment level and type of basic insurance) and a residual term to overall inequality in oral health service utilization. Results: The significant positive EI and HI values indicated that pro‐rich inequality and inequity in oral health service utilization exist among Chinese adults. Income and type of basic medical insurance contributed the most to socioeconomic‐related inequality in the use of oral health services among adults aged 55‐64 and 65‐74 years. However, the main driving factors of socioeconomic inequality among adults aged 35‐44 years in dental care use included income, educational achievement, type of basic medical insurance and residential location. The need variables accounted for a very small proportion of overall socioeconomic‐related inequality in oral health service use in all three groups. Conclusions: Oral healthcare service utilization was disproportionately concentrated among better‐off Chinese adults. The primary determinants of inequality in dental care use in different age groups provide information for policymakers to create more targeted policies to achieve equity in the oral healthcare system in China. [ABSTRACT FROM AUTHOR]

Dufulin is a new type of chiral antiplant virus agent independently developed in China. The present study was conducted to determine the effects of different concentrations of rac‐dufulin and dufulin enantiomers (1, 5, and 10 mg/L) on oxidative stress in Tubifex after exposure for 3, 7, and 14 d. Results showed that rac‐dufulin and individual enantiomers had no significant effects on total protein content and glutathione reductase activities. Increased superoxide dismutase demonstrated the generation of superoxide anion radical. The increase in glutathione S‐transferase may be due to detoxification mechanisms. The different changes in catalase activities could be due to oxidative stress. The increase in malondialdehyde may be due to the accumulation and toxicity of contaminations. The degradation behavior of dufulin enantiomers was studied through spiked‐water and spiked‐soil tests. The degradation rate of S‐(+)‐dufulin was faster than that of R‐(−)‐dufulin. The present study demonstrated the occurrence of enantioselectivity in the degradation and oxidative stress of dufulin to Tubifex. In spiked soil, the concentrations of dufulin enantiomers in underlying soil were significantly higher than those in overlying water; but after 5 d of degradation, the bioturbation of Tubifex could facilitate part of dufulin diffusing from the underlying soil into the overlying water and altered the partitioning of dufulin. The present study provided a basis for conducting environmental safety risk assessments and rationally using dufulin as a chiral pesticide. Environ Toxicol Chem 2020;39:2136–2146. © 2020 SETAC [ABSTRACT FROM AUTHOR]

BACKGROUND The rice bacterial leaf blight (BLB) is one of the most serious bacterial diseases caused by Xanthomonas oryzae pv. oryzae (Xoo), which can cause yield loss of rice up to 50%. The three‐dimensional quantitative structure–activity relationship (3D‐QSAR) is an important auxiliary method to find potential high‐efficient pesticides active structures. RESULTS: A series of novel 1,3,4‐oxadiazole compounds were designed and synthesized based on the 3D‐QSAR model, and their antibacterial activities in vitro against Xoo were evaluated. The results indicated that all the target compounds showed excellent in vitro antibacterial activities. For example, the compounds 6, 12, 13, 20, 21, and 23 exhibited excellent antibacterial activities against Xoo, with half‐maximal effective concentration (EC50) values of 0.24, 0.31, 0.36, 0.29, 0.19, and 0.31 mg/L, respectively, which were superior to the antibacterial agents thiodiazole copper (127.44 mg/L) and bismerthiazol (91.08 mg/L). Meanwhile, compound 21 showed good antibacterial activity in vivo against BLB, with curative and protective activities of 46.7% and 56.4%, respectively, which were superior to thiodiazole copper (28.5% and 32.5%) and bismerthiazol (37.6% and 38.4%). Compound 21 can significantly reduce the extracellular polysaccharides production of Xoo, increase the permeability of the cell membranes, and also can cause cell surface wrinkles, deformation and dryness. CONCLUSION: The 3D‐QSAR model can be used to find sulfone compounds containing a 1,3,4‐oxadiazole moiety with higher antibacterial activity, and compound 21 can be used as a potential antibacterial agent in the future. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Using LC–MS/MS, a rapid and sensitive method for the simultaneous determination of pyraclostrobin and azoxystrobin residues in banana matrices (leaf and whole banana) and soil was established. The samples were extracted using acetonitrile and purified through C18 dispersive solid‐phase extraction. The average recovery of the analytes in various matrices was in the range of 77.3%–103.9% with an RSD range of 0.9%–9.5%. The initial deposition amounts of pyraclostrobin and azoxystrobin at 2 h in the banana leaves of the mineral oil group were 1.43 and 1.31 times in Guangxi, and 2.10 and 1.81 times in Hainan for the water group, whereas those in the soil of the water group were 3.45 and 3.03 times in Guangxi, and 2.14 and 3.48 times in Hainan for the mineral oil group. The half‐lives in the leaves and soil of the mineral oil group were not remarkably different from those of the water group. The terminal residue of the analytes on the whole banana was <0.02 mg/kg at 14 days after application from the two sites. The results of this work may indicate and promote the safety of using pyraclostrobin and azoxystrobin in banana production, especially with mineral oil spray adjuvants. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ensuring the yield, quality, and profitability of okra by preventing and controlling pests with the application of insecticides has increased in the last decade. Some insecticide residues might remain in edible parts of okra (fruits) and lead to several potential human health problems. Therefore, research on the residue behaviour, risk assessment and removal approach of insecticides on okra fruits is important for food safety, together with the proper application and residual elimination of insecticides in okra. RESULTS: A simple liquid chromatography with tandem mass spectrometry (LC–MS/MS) method was established and validated for determining the tebufenozide residues in okra fruits. The recoveries of tebufenozide in okra fruits were >72% with relative standard deviations of 0.6 to 6.1%. The dissipation rates of tebufenozide were different in okra fruits cultivated under open land and glasshouse field conditions because of the discriminating humidity and temperature conditions. The dietary intake of the tebufenozide residues from okra fruit consumption for Chinese consumers was fairly low, with approximately no potential health risk. The processing factor values of washing, blanching, washing + blanching and soaking were all less than one, which indicated that these processes could effectively reduce the residual hydrazide in the okra fruit. CONCLUSION: The developed method for analysing tebufenozide in okra fruits was applicable for field studies on this insecticide. The potential health risk of tebufenozide in okra fruits could be negligible to the health of different age groups of Chinese consumers. The soaking process effectively removed tebufenozide residues from okra fruits. The obtained data will help Chinese governments establish a maximum residue limit of tebufenozide in okra and provide data for the risk assessment and removal of tebufenozide in other crops. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Objectives: To explore the factors associated with utilization of oral health services among Chinese adults and older adults according to the Andersen Behavior Model. Methods: Data from the 4th National Oral Health Survey (2015‐2016) in China were used. A total of 7206 people (3669 adults aged 35‐44 years and 3537 older adults aged 65‐74 years) were included in our analysis. Oral health service utilization in the past 12 months was the outcome variable. Explanatory variables were selected according to the Andersen Behavior Model. Descriptive statistics and bivariate associations (chi‐square tests) were analysed, followed by hierarchical Poisson regression models, which were conducted to determine the factors associated with oral health service utilization. Results: In total, 21.4% (95% CI: 19.4%‐23.7%) of adults (35‐44 years old) and 20.7% (95% CI: 18.6%‐22.9%) of older adults (65‐74 years old) utilized oral health services in the past 12 months. Nearly 80% of adults (78.7%, 95% CI: 74.0%‐82.7%) and more than 90% of older adults (93.7%, 95% CI: 91.0%‐95.6%) visited a dentist for treatment. Adults aged 35‐44 years old who were female (IRR: 1.15, 95% CI: 1.00‐1.33, P =.047), had good oral health knowledge and attitudes (IRR: 1.30, 95% CI: 1.06‐1.59, P =.011), perceived their oral health status as fair (IRR:1.51, 95% CI:1.24‐1.85, P <.001) or poor/very poor (IRR:2.52, 95% CI:2.01‐3.18, P <.001) and had a decayed, missing and filled teeth (DMFT) index >0 (IRR: 1.52, 95% CI: 1.11‐2.09, P =.009) were more likely to report dental visits in the past 12 months. Older adults who utilized oral health services tended to be female (IRR: 1.32, 95% CI: 1.09‐1.59, P =.004); to be covered by Urban Resident Basic Medical Insurance (URBMI) (IRR: 1.56, 95% CI: 1.18‐2.05, P =.002), Urban Employee Basic Medical Insurance (UEBMI) (IRR: 1.69, 95% CI: 1.32‐2.16, P <.001) or government medical insurance (GMI) (IRR: 1.03, 95% CI:1.01‐2.16, P =.044); to have a high education level (IRR: 1.37, 95% CI: 1.08‐1.74, P =.010); to have an income level in the 2nd tertile (IRR: 1.44, 95% CI: 1.13‐1.84, P =.003) or 3rd tertile (IRR:1.52, 95% CI:1.18‐1.95, P =.001); and to perceive their oral health status as poor or very poor (IRR: 1.53, 95% CI: 1.21‐1.95, P =.001). Conclusions: Sex and self‐perceived oral health status were associated with oral health utilization among Chinese population. Additionally, for older adults, education level, household income and insurance coverage were determinants of dental service use. These findings can aid in creating more targeted policies to increase the use of dental services by Chinese adults. [ABSTRACT FROM AUTHOR]

BACKGROUND Increasing numbers of fruit swelling agents have been used to improve the fruit rate and production yield of strawberries in recent years. The abuse of fruit swelling agents could lead to an increase in the deformation rate and abnormal coloration of strawberry and a decrease in quality at harvest. Therefore, understanding the harmful effects of fruit swelling agents on strawberry will provide guidance for their reasonable use. RESULTS: The residual determination method for measuring thidiazuron (TDZ) in strawberry was developed and validated by liquid chromatography and tandem mass spectrometry (LC‐MS/MS). The recoveries of TDZ in strawberry were 97.9–108.5% with relative standard deviations of 0.9% to 5.3%. The dissipation rates of TDZ were different in strawberries cultivated under field and indoor conditions due to the differences in temperature and humidity. The ascorbic acid content increased when TDZ was applied at 2 mg kg−1. The SOD (superoxide dismutase), POD (peroxidase) and CAT (catalase) activities of strawberry tended to decrease and subsequently increase following the application of TDZ, and the opposite changes occurred on the malondialdehyde (MDA) content of TDZ‐treated strawberry. CONCLUSIONS: The analytical method for measuring TDZ in strawberry that was developed was suitable for dissipation studies on this compound. Antioxidant enzyme activities and the MDA content of strawberry were altered, and some reverse effects, such as membrane damage, were inhibited when TDZ was applied. The data obtained in this study might provide suggestions to reduce the adverse effects of TDZ on strawberry and may help to guide the safe and proper use of TDZ in strawberry. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A liquid chromatography with tandem mass spectrometry method was developed and validated to simultaneously determine chlorpyrifos, imidacloprid, and imidacloprid metabolites in soil, wheat grain, and wheat straw matrices. Satisfactory linearity (R2 ≥ 0.9965) of the method was obtained for all analytes. The ranges of limits of detection and limits of quantification for seven analytes in three matrices were 0.17–66.7 and 0.5–200 μg/kg, respectively. Average recoveries were 72.85–81.25% for chlorpyrifos, 78.54–84.70% for imidacloprid, 73.83–81.03% for imidacloprid olefin, 71.47–80.61% for 5‐hydroxy imidacloprid, 71.79–81.32% for imidacloprid urea, 70.42–82.20% for imidacloprid nitroguanidine, and 70.91–82.46% for imidacloprid 6‐chloronicotinic acid in soil, wheat grain, and wheat straw. The intra‐ and interday relative standard deviations were less than 8%. The established method was successfully applied for the residual analysis of chlorpyrifos, imidacloprid, and imidacloprid metabolites in actual soil, wheat grain, and wheat straw samples. The results indicated that the established method could be used to detect trace amounts of chlorpyrifos, imidacloprid, and imidacloprid metabolites in wheat and that the method might be able to provide some data on the detection of these seven compounds in other crops. [ABSTRACT FROM AUTHOR]

Abstract: A chiral liquid chromatography–tandem high resolution mass spectroscopic method was developed for the analysis of indoxacarb enantiomers in rice plants, rice hulls and brown rice. Chiral separation of two enantiomers was carried out on a Superchiral S‐OD column maintained at 20°C and eluted with 0.3 mL/min methanol. Samples were extracted by acetonitrile solution with ultrasound and cleansed by dispersive solid‐phase extraction of 50 mg of primary secondary amine and 50 mg of C18. This method was successfully used to study the degradation and residues of two enantiomers with enriched S‐indoxacarb (2.33S/1R) and pure S‐indoxacarb in rice plants. The half‐lives of R‐indoxacarb and S‐indoxacarb were 4.20–4.33 and 3.45–3.57 days in rice plants during the degradation of enriched S‐indoxacarb in Guizhou and Hunan, respectively, whereas the half‐lives of pure S‐indoxacarb were 2.68 and 3.69 days in Guizhou and Hunan, respectively. The results indicated that preferential S‐indoxacarb degradation occurred and that enantiomeric transformation was absent in the total experiment periods of pure S‐indoxacarb in rice plants. The final residue concentrations of indoxacarb enantiomers in brown rice were significantly less than those in rice plants and rice hulls in the same rice field after applying indoxacarb SC and indoxacarb EC. [ABSTRACT FROM AUTHOR]

Abstract: A simple and rapid method for enantioselective determination of dufulin in cucumber and soil was developed by liquid chromatography with tandem mass spectrometry. The enantiomers were separated on a Superchiral S‐OD chiral cellulose tris(3,5‐dimethylphenylcarbamate) column at 20°C, with a mixture of acetonitrile and water (0.1% formic acid; 52:48, v/v) as mobile phase at a flow rate of 0.65 mL/min. The pretreatment conditions were optimized using an orthogonal test, and the optimized method showed good linearity and sensitivity. The limits of detection and limits of quantification of two dufulin enantiomers were 0.006 and 0.02 mg/kg, respectively. The average recoveries of S‐enantiomer and R‐enantiomer in cucumber and soil were 80.61–99.83% and 80.97–102.96%, respectively, with relative standard deviations of 1.30–9.72%. The method was successfully applied to determine dufulin in real cucumber and soil samples. The results demonstrate that the method could facilitate further research on the differences between individual dufulin enantiomers with respect to metabolites and environmental fate and finally help reveal the complex interactions that exist between dufulin, humans and the environment. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a modified quick, easy, cheap, effective, rugged and safe method coupled with gas chromatography with electron capture detection was established to determine dimethachlon residues in paddy soil, rice husk, rice straw, brown rice and cooked rice. The limits of quantification of dimethachlon were 0.01 mg/kg for paddy soil, brown rice and cooked rice and 0.02 mg/kg for rice straw and rice husk. The mean recoveries were in the range 78.59–104.7% with relative standard deviation values of <10% for dimethachlon in the five matrices. For field experiments, the final residues of dimethachlon in paddy soil were < 0.05 mg/kg and were < 1.21 mg/kg in rice straw from six sites. The final residues of dimethachlon in the brown rice at 21, 28 and 35 days after spraying from six sites were 0.08–7.58 mg/kg, and 0.16–30.1 mg/kg in rice husk. Our six test sites covered the main rice–producing areas of China. The routine rice cooking process of a Chinese family could apparently increase the removal of dimethachlon in rice compared with brown rice, and the reduction ratios were > 96%. [ABSTRACT FROM AUTHOR]

Abstract: A simple analytical method was developed to simultaneously determine thiamethoxam and its metabolite, clothianidin, in fresh tobacco leaf, soil and cured tobacco leaf using liquid chromatography with tandem mass spectrometry. Thiamethoxam and clothianidin in tobacco and soil samples were extracted with acetonitrile containing 0.1% formic acid and purified using an NH2‐SPE column. The optimized method provided good linearity with coefficients of determination R2 ≥ 0.9981. The limits of detection and quantification were between 0.006–0.12 and 0.02–0.4 mg/kg, respectively. Intra‐ and inter‐day recovery assays were used to validate the established method. The average recoveries of thiamethoxam and clothianidin in fresh tobacco leaf, soil and cured tobacco leaf were 75.04–100.47%, 75.86–86.40% and 89.83–99.39%, respectively. The intra‐ and inter‐day relative standard deviations were all <9%. The developed method was successfully applied for the analysis of thiamethoxam and clothianidin residues in actual tobacco and soil samples. The results indicated that the established method met the requirements for the analysis of trace amounts of thiamethoxam and clothianidin in fresh tobacco leaf, soil and cured tobacco leaf. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: The literature shows that bisthioether and 1,3,4‐oxadiazole derivatives exhibit a wide variety of biological activities. In this study, a series of novel bisthioether derivatives containing a 1,3,4‐oxadiazole moiety were synthesized and their antibacterial and nematocidal activities investigated. RESULTS: Among the title compounds evaluated, compound 4f demonstrated the best antibacterial activities against rice bacterial leaf blight, rice bacterial leaf streak and citrus canker caused by Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas oryzae pv. oryzicola (Xoc) and Xanthomonas axonopodis pv. citri (Xac), with EC50 values of 4.82, 11.15 and 16.57 µg mL–1, respectively, which were even better than those of thiodiazole copper and bismerthiazol. Meanwhile, compound 4f had better in vitro nematocidal activity against Caenorhabditis elegans at 48 h, with an LC50 value of 2.89 µg mL–1, which was superior to those of ethoprophos and fosthiazate. In addition, greenhouse trials indicated that compound 4f was effective in reducing rice bacterial leaf blight relative to thiodiazole copper and bismerthiazol. CONCLUSION: A series of novel bisthioether derivatives containing a 1,3,4‐oxadiazole moiety were synthesized and bioassay results showed that compound 4f exhibited the best antibacterial and nematocidal activities. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: A simple method was developed and validated for the simultaneous determination of metalaxyl, cyazofamid and the cyazofamid metabolite 4‐chloro‐5‐p‐tolylimidazole‐2‐carbonitrile (CCIM) by liquid chromatography with tandem mass spectrometry. The three target compounds were extracted from tobacco and soil with acetonitrile containing 0.1% acetic acid, and the extracts were purified using octadecylsilane. The proposed method showed satisfactory linearity (R2 ≥ 0.9985) for the target compounds. The limits of detection for metalaxyl, cyazofamid and CCIM were 0.006, 0.06 and 0.06 mg/kg in soil and green tobacco leaves and 0.03, 0.3 and 0.3 mg/kg in cured tobacco leaves, respectively. The limits of quantification for metalaxyl, cyazofamid and CCIM were 0.02, 0.2 and 0.2 mg/kg in soil and green tobacco leaves and 0.1, 1 and 1 mg/kg in cured tobacco leaves, respectively. The average recoveries from soil and tobacco were 72.91–98.40% for metalaxyl, 76.73–105.80% for cyazofamid and 74.48–106.45% for CCIM. The relative standard deviation range was 1.23–6.99%. The developed method was successfully applied to analysis of residues of metalaxyl, cyazofamid and CCIM in real soil and tobacco samples. The results indicated that the established method could meet the requirement for the analysis of trace amounts of all three analytes in soil and tobacco. [ABSTRACT FROM AUTHOR]

Abstract: A modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for the simultaneous determination of spirotetramat and its four metabolite residues in citrus, peel, pulp and soil was developed and validated by liquid chromatography with tandem mass spectrometry (LC‐MS/MS). The samples were extracted with acetonitrile (1%, glacial acetic acid, v/v) and purified using primary secondary amine and octadecylsilane. The limit of detection was 0.01–0.13 mg/kg, whereas that of quantification was 0.02–0.40 mg/kg for spirotetramat and its metabolites. The average recoveries of spirotetramat, spirotetramat‐enol, spirotetramat‐mono‐hydroxy, spirotetramat‐enol‐glucoside and spirotetramat‐ketohydroxy in all matrices were 73.33–107.91%, 75.93–114.85%, 76.44–100.78%, 71.46–103.19% and 73.08–105.27%, respectively, with relative standard deviations < 12.32%. The dissipation dynamics of spirotetramat in citrus and soil followed first‐order kinetics, with half‐lives of 2.3–8.5 days in the three sampling locations. The terminal residues of spirotetramat in four matrices at the three locations were measured below the 1.0 mg/kg maximum residue limit set by China, and residues were found to be concentrated on the peel. The risk assessment of citrus was evaluated using risk quotients. The risk quotient values were found to be significantly <1, suggesting that the risk to human health was negligible when using the recommended doses of spirotetramat in citrus. These results could provide guidance for the safe and proper application of spirotetramat in citrus in China. [ABSTRACT FROM AUTHOR]

Abstract: A simple method was developed and validated for the simultaneous determination of clethodim, clethodim sulfoxide, and clethodim sulfone in soil and tobacco by liquid chromatography with tandem mass spectrometry. The three target compounds were extracted from tobacco and soil with acetonitrile, and the extracts were purified using octadecyl silane. The proposed method showed satisfactory linearity (R2 ≥ 0.9973) for the target compounds. The limits of detection and quantitation of the three analytes in all matrices were 0.024−0.06 and 0.08−0.2 mg/kg, respectively. The recovery was tested in blank soil and tobacco leaf samples and calculated to be 74.8–104.4% with relative standard deviations of 1.9–12.1%. The developed method was successfully applied to the analysis of residues of clethodim, clethodim sulfoxide and clethodim sulfone in real soil and tobacco samples. The results indicated that the developed method can meet the requirements for the analysis of trace amounts of all three analytes in soil and tobacco. [ABSTRACT FROM AUTHOR]

Abstract: A gas chromatography–tandem mass spectrometry method was developed and validated to simultaneously determine boscalid and fludioxonil in grape and soil samples. These samples were extracted with 10 mL of acetonitrile and purified using a mixed primary secondary amine/octadecylsilane sorbent. The method showed good linearity (R2 > 0.99) in the calibration range 0.005–2 μg/mL for both pesticides. The limits of detection and quantification for the two analytes in grape and soil were 0.006 and 0.02 mg/kg, respectively. Fungicide recoveries in grape and soil were 81.18–92.11% for boscalid and 82.73–97.67% for fludioxonil with relative standard deviations of 1.31–10.31%. The established method was successfully applied to the residual analysis of boscalid and fludioxonil in real grape and soil samples. The terminal residue concentrations of boscalid and fludioxonil in grape samples collected from Anhui and Guizhou were <5 mg/kg (the maximum residue limit set by China) 7 days after the last application and 1 mg/kg (the maximum residue limit set by USA) 14 days after the last application. These results could provide guidance for the proper and safe use of boscalid and fludioxonil in grape and help the Chinese government to establish an MRL for fludioxonil in grape. [ABSTRACT FROM AUTHOR]

Abstract: A liquid chromatography–electrospray ionization tandem mass spectrometry method was developed for simple and accurate detection of the fungicides difenoconazole, propiconazole and pyraclostrobin in peppers and soil. Three fungicides residues were extracted from samples by acetonitrile and cleaned up by dispersive solid‐phase extraction before instrumental analysis. The accuracy and precision of the method were evaluated by conducting an intra‐ and inter‐day recovery experiment. The limits of quantification and detection of difenoconazole, propiconazole and pyraclostrobin in pepper and soil were 0.005 and 0.0015 mg/kg, respectively. The recoveries were investigated by spiking pepper and soil at three levels, and were found to be in the ranges 79.62–103.15% for difenoconazole, 85.94–103.35% for propiconazole and 80.14–97.69% for pyraclostrobin, with relative standard deviations <6.5%. Field experiments were conducted in three locations in China. The half‐lives of difenoconazole, propiconazole and pyraclostrobin were 5.3–11.5 days in peppers and 6.1–32.5 days in soil. At harvest, pepper samples were found to contain difenoconazole, propiconazole and pyraclostrobin well below the maximum residue limits of European Union at the interval of 21 days after last application following the recommended dosage. [ABSTRACT FROM AUTHOR]

An optimized quick, easy, cheap, effective, rugged and safe method for the simultaneous determination of difenoconazole, trifloxystrobin and its metabolite trifloxystrobin acid residues in watermelon and soil was developed and validated by gas chromatography with tandem mass spectrometry. The samples were extracted with acetonitrile (1% formic acid) and cleaned up by dispersive solid-phase extraction with octadecylsilane sorbent. The limit of quantification of the method was 0.01 mg/kg, and the limit of detection was 0.003 mg/kg for all three analytes. The recoveries of the fungicides in watermelon, pulp and soil were 72.32-99.20% for difenoconazole, 74.68-87.72% for trifloxystrobin and 78.59-92.66% for trifloxystrobin acid with relative standard deviations of 1.34-14.04%. The dissipation dynamics of difenoconazole and trifloxystrobin in watermelon and soil followed the first-order kinetics with half-lives of 3.2-8.8 days in both locations. The final residue levels of difenoconazole and trifloxystrobin were below 0.1 mg/kg (maximum residue level [MRL] set by China) and 0.2 mg/kg (MRL set by European Union), respectively, in pulp samples collected 14 days after the last application. These results could help Chinese authorities to establish MRL of trifloxystrobin in watermelon and provide guidance for the safe and proper application of both fungicides on watermelon. [ABSTRACT FROM AUTHOR]

An effective and sensitive chiral analytical method was established to investigate the stereoselective dissipation of rac-dufulin in watermelon using ultra high performance liquid chromatography with a superchiral S-OD chiral column (4.6 × 150 mm i.d., 5 μm) coupled with high-resolution mass spectrometry. To optimize the pretreatment method for detecting rac-dufulin in the three matrixes, different extraction solvents, extractant volumes, extraction times, and absorbents were investigated to improve extraction efficiency. Moreover, analysis of variance was used to perform method validation for determination of the two dufulin enantiomers in the three matrixes. Using the optimized method, good linearity was obtained (determination coefficient > 0.999). The limits of detection and quantification of the two dufulin enantiomers in soil, watermelon, and pulp were 0.15 and 0.5 μg/kg, respectively. The average recoveries of the two enantiomers in the three matrixes at four spiked levels ranged from 75.0 to 107.8%, with intra- and inter-day relative standard deviations of 0.4-10.4%. In field trials, the R enantiomer was preferentially dissipated in watermelon. These method validation results confirmed that the developed method was convenient and reliable for the stereoselective determination of enantiomers of rac-dufulin in watermelon. [ABSTRACT FROM AUTHOR]

BACKGROUND Ferulic acid and quinazoline derivatives possess good antiviral activities. In order to develop novel compounds with high antiviral activities, a series of ferulic acid ester derivatives containing quinazoline were synthesized and evaluated for their antiviral activities. RESULTS Bioassays indicated that some of the compounds exhibited good antiviral activities in vivo against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV). One of the compounds demonstrated significant curative and protective activities against TMV and CMV, with EC50 values of 162.14, 114.61 and 255.49, 138.81 mg L−1, respectively, better than those of ningnanmycin (324.51, 168.84 and 373.88, 272.70 mg L−1). The values of q2 and r2 for comparative molecular field analysis and comparative molecular similarity index analysis in the TMV (0.508, 0.663 and 0.992, 0.930) and CMV (0.530, 0.626 and 0.997, 0.981) models presented good predictive abilities. CONCLUSION Some of the title compounds demonstrated good antiviral activities. Three-dimensional quantitative structure-activity relationship models revealed that the antiviral activities depend on steric and electrostatic properties. These results could provide significant structural insights for the design of highly active ferulic acid derivatives. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

To find new antiviral agents, novel chalcone derivatives containing a purine moiety were designed and synthesized by combining bioactive substructures. The antiviral activities of the derivatives against tobacco mosaic virus ( TMV) and cucumber mosaic virus ( CMV) were evaluated. Results showed that most of the derivatives showed antiviral activities. Compounds 3n and 3p exhibited excellent curative, protective and inactivation activities against TMV, with the EC50 values of 452.4, 416.2, 241.2 and 438.7, 418.6, 261.7 µg• mL−1, respectively, which were better than those of ribavirin (585.8, 436.0 and 268.7 µg• mL−1). Compounds 3n and 3p showed remarkable curative and protective activities against CMV. Compound 3n showed a moderate affinity to TMV coat protein, with binding constant Ka and Kd values of 1.5 × 104 L•mol−1 and 79.8 µmol•L−1, respectively. These findings provided an important structural insight for further designs of highly active chalcone derivatives and a basis for further study on their mechanism of action. [ABSTRACT FROM AUTHOR]

A series of novel 1-(3-chloropyridin-2-yl)- N-substituted-5-(trifluoromethyl)-pyrazole carboxamide derivatives TC1, TC2, TC3, TC4, TC5, TC6, TC7, TC8, TC9, TC10, TC11 were synthesized and characterized by IR, 1H NMR, 13C NMR, MS, and elemental analysis. All the target compounds were tested in vitro for their antibacterial activities and antifungal activities. The preliminary bioassays indicated that compound TC6 exhibited excellent activity against Xanthomonas oryzae (94.9% and 84.9%) at different concentrations (200 µg/mL and 100 µg/mL), which was higher than that of Bismerthiazol (94.6% and 64.0%), respectively. At the same time, most of the compounds exhibited moderate antifungal activities against four kinds of phytopathogenic fungi [ABSTRACT FROM AUTHOR]

A fast and simple analytical method was developed for the simultaneous determination of RH-5849 and indoxacarb in soil, rice straw, rice husk and brown rice. QuEChERS (quick, easy, cheap, effective, rugged and safe) method was used for extraction, and liquid chromatography with tandem triple quadrupole mass spectrometry was used for quantification. The matrix-matched calibration plots were linear in the range between 25 and 5000 μg/L for soil, rice straw, rice husk and brown rice samples. All determination coefficients ( R2) were ≥0.9962. The limits of detection and quantification were 1.5 and 5 μg/kg, respectively. Recoveries at three fortification levels ranged between 79.5 and 97.9% with relative standard deviations <11%. The developed method was validated and applied for the analysis of dissipation study samples. For field experiments, the half-lives of RH-5849 and indoxacarb in rice straw were 11.93 and 5.83 days, respectively. The method was demonstrated to be reliable for the routine monitoring of RH-5849 and indoxacarb in rice samples. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This study describes the development and use of a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with gas chromatography with mass spectrometry to determine 29 pesticide residues in green, red and dehydrated red peppers. Pesticides were extracted with acetonitrile (1% acetic acid), partitioned with sodium chloride and purified with primary secondary amino and octadecyl silane in acetone. The QuEChERS extraction conditions were optimized, and the matrix effects that might influence recoveries were evaluated and minimized using matrix-matched calibration curves. Under the optimized conditions, the calibration curves for 29 pesticides showed good linearity in the concentration range of 0.1-10 μg/mL with determination coefficient R2 > 0.998. The limits of quantification of the 29 pesticides were 0.006-0.06 mg/kg for green pepper, 0.005-0.039 mg/kg for red pepper and 0.014-0.25 mg/kg for dehydrated red pepper. These values are below the suggested regulatory maximum residue limits. The mean recoveries ranged between 70.1 and 110%, and the relative standard deviations were <13%. The developed method was successfully applied to commercial samples. Some samples were found to contain the 29 pesticides with levels below the legal limits. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

BACKGROUND 1,4-Pentadien-3-one and 1,3,4-oxadiazole derivatives possess good antiviral activities, and their substructure units are usually used in antiviral agent design. In order to discover novel molecules with high antiviral activities, a series of 1,4-pentadien-3-one derivatives containing the 1,3,4-oxadiazole moiety were designed and synthesised. RESULTS Bioassays showed that most of the title compounds exhibited good inhibitory activities against tobacco mosaic virus ( TMV) in vivo. The compound 8f possessing the best protective activity against TMV had an EC50 value of 135.56 mg L−1, which was superior to that of ribavirin (435.99 mg L−1). Comparative molecular field analysis ( CoMFA) and comparative molecular similarity index analysis ( CoMSIA) techniques were used in three-dimensional quantitative structure-activity relationship ( 3D-QSAR) studies of protective activities, with values of q2 and r2 for the CoMFA and CoMSIA models of 0.751 and 0.775 and 0.936 and 0.925 respectively. Compound 8k with higher protective activity ( EC50 = 123.53 mg L−1) according to bioassay was designed and synthesised on the basis of the 3D-QSAR models. CONCLUSION Some of the title compounds displayed good antiviral activities. 3D-QSAR models revealed that the appropriate compact electron-withdrawing and hydrophobic group at the benzene ring could enhance antiviral activity. These results could provide important structural insights for the design of highly active 1,4-pentadien-3-one derivatives. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This study developed and used a modified quick, easy, cheap, efficient, rugged and safe (QuEChERS) method coupled with gas chromatography with electron capture detection to determine eight pyrethroid pesticide residues in green, red and dehydrated red peppers. Pyrethroids were extracted with acetonitrile, partitioned with sodium chloride and purified with primary secondary amino and graphitized carbon black in hexane. The QuEChERS extraction conditions were optimized, and the matrix effects that might influence recoveries were evaluated and minimized using matrix-matched calibration curves. Under the optimized conditions, the calibration curves for pyrethroid pesticides showed good linearities in the concentration range of 0.05-20 µg/mL with determination coefficients ( R2) >0.997. The limits of quantification of eight pyrethroids were 0.004-0.04 mg/kg for green and red pepper and 0.04-0.5 mg/kg for dehydrated red pepper. These values are below the suggested regulatory maximum residue limits. The mean recoveries ranged between 79.0 and 104%, and the relative standard deviations were <11%. The developed method was successfully applied to commercial samples. Some samples were found to contain pyrethroid pesticides with levels below the legal limits. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The degradation of indoxacarb enriched with (+)-S-indoxacarb (S/R:70/30) was investigated in three typical green teas. A convenient and precise chiral method was developed and validated for measuring indoxacarb enantiomers in green tea. The developed method was based on high-performance coupled with tandem using a Chiralpak IC column. The degradation of indoxacarb enantiomers showed that the (+)-S-enantiomer dissipated faster than the (−)-R-enantiomer in all three typical tea farms. However, no enantiomerization was observed after applying pure (+)-S-indoxacarb. Residues on tea plant of the active ingredient (+)-S-indoxacarb from suspension concentrate (SC) was more persistent than that from emulsifiable concentrate (EC). Chirality 27:262-267, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT Direct semipreparative enantioseparation of indoxacarb was performed on a semipreparative Chiralpak IA column using normal-phase high-performance liquid chromatography (HPLC) with n-hexane-isopropanol-ethyl acetate (70:20:10) mixture as mobile phase. Degradation of indoxacarb (2.33 S + 1 R) and its two enantiopure isoforms in three aqueous buffer solutions and four water samples collected from natural water sources was then elucidated by HPLC analysis on Chiralpak IA column. Degradation of all three indoxacarbs complied with first-order kinetics and demonstrated linearity with regression coefficients R2 > 0.88. Indoxacarb (2.33 S + 1 R) underwent enantioselective degradation in river water, rain water, and buffer solution of pH 7.0. Enantiopure S-(+)-indoxacarb and R-(−)-indoxacarb were both found to be configurationally stable in water. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A series of sulfone derivatives containing 1, 3, 4-oxadiazole moiety were prepared and evaluated for their antibacterial activities by the turbidimeter test. Most compounds inhibited growth of Ralstonia solanacearum ( R. solanacearum) from tomato and tobacco bacterial wilt with high potency, among which compounds 5a and 5b exhibited the most potent inhibition against R. solanacearum from tomato and tobacco bacterial wilts with EC50 values of 19.77 and 8.29 μg/mL, respectively. Our results also demonstrated that 5a, 5b, and a number of other compounds were more potent than commercial bactericides Kocide 3000 and Thiodiazole Copper, which inhibited R. solanacearum from tomato bacterial wilt with EC50 values of 93.59 and 99.80 μg/mL and tobacco bacterial wilt with EC50 values of 45.91 and 216.70 μg/mL, respectively. The structure-activity relationship (SAR) of compounds was studied using three-dimensional quantitative structure-activity relationship (3 D- QSAR) models created by comparative molecular field analysis ( Co MFA) and comparative molecular similarity index analysis ( Co MSIA) based on compound bioactivities against tomato and tobacco bacterial wilts. The 3 D- QSAR models effectively predicted the correlation between inhibitory activity and steric-electrostatic properties of compounds. [ABSTRACT FROM AUTHOR]

A series of cis- and trans-isomers of hydrazone derivatives were separated and analyzed through HPLC with diode-array detection and HPLC- MS/ MS using ESI and ion trap MS. Two single crystals ( A-5-1 and C-2-1) of the trans-isomers were obtained and determined using X-ray crystallography data, and the cis- to trans-isomerization under different conditions was discussed. Both of the cis- and trans-isomers of A-4 and A-5 exhibited good insecticidal activities against Plutella xylostella. [ABSTRACT FROM AUTHOR]

The direct HPLC enantioseparation of a novel series of chiral pyridazin-3(2 H)-one derivatives with α -aminophosphonate moiety was performed on two immobilized polysaccharide chiral stationary phases (Chiralpak IA, Chiralpak IC) using n-hexane ( n-Hex)/dichloromethane (DCM) mobile phase with 5% alcohol additive. Good baseline separation of the enantiomers was achieved using amylose tris-(3,5-dimethylphenylcarbamate) chiral stationary phases (Chiralpak IA) on analytical scale. The analytical method was further scaled up to semi-preparative loading to obtain small amounts of both the enantiomers of pyridazin-3(2 H)-one derivative. The semi-preparative resolution of all compounds was successfully achieved with n-hexane/dichloromethane/ethanol (EtOH) as mobile phase using a semi-preparative Chiralpak IA column. The first fractions were isolated with purities of >99.9% (enantiomeric excess (e.e.), and the second fractions were obtained with purities of >98.2% (enantiomeric excess). The assignment of the absolute configuration was established for the F1 fraction of compound a-2 by single-crystal X-ray diffraction method. [ABSTRACT FROM AUTHOR]

The back cover image is based on the Research Article Ferulic acid derivatives with piperazine moiety as potential antiviral agents by Ting Yuan et al., https://doi.org/10.1002/ps.6794. [ABSTRACT FROM AUTHOR]