-
ACS Omega Jun 2021Halogen-halogen nonbonded interactions were studied for methyl halides and phenyl halides using both B3LYP and MP2 along with 6-311+G* and aug-cc-pVTZ. With the methyl...
Halogen-halogen nonbonded interactions were studied for methyl halides and phenyl halides using both B3LYP and MP2 along with 6-311+G* and aug-cc-pVTZ. With the methyl halides, the linear approach was found to lead to little stabilization, whereas the "90°" approach gave 1-2 kcal/mol. This modest stabilization was due to long-range electron correlation effects. The lowest-energy arrangement had the molecules side-by-side, with the major stabilization being derived from halogen-hydrogen interactions. The results for methyl bromide were quite similar. Chlorobenzene dimer with the 90° orientation gave a small stabilization energy, but the best arrangement had the two benzene rings oriented over each other. The meta orientation of the chlorines had a lower energy than ortho or para. The dimerization energy was larger than that for two benzene rings sitting directly above each other, suggesting that whereas Cl···Cl interaction is not very important, the effect of the halogen on the electron distribution does have an effect. This suggests that much of the crystallographic results for these compounds may not be due to halogen-halogen interactions but rather the interaction between the substituted benzene rings along with crystal forces.
PubMed: 34151099
DOI: 10.1021/acsomega.1c01356 -
Pest Management Science Nov 2021Nematode and disease resistant rootstocks have been developed for many vegetable crops including tomato, eggplant, melon, watermelon, and cucumber and are being utilized... (Review)
Review
Nematode and disease resistant rootstocks have been developed for many vegetable crops including tomato, eggplant, melon, watermelon, and cucumber and are being utilized by an increasing number of growers. Grafting commercially desirable vegetable scions on nematode and disease resistant rootstocks has been significantly stimulated by the need for an alternative to banned soil fumigation with methyl bromide, which had been the primary method for managing soil-borne nematodes, diseases, and weeds. Rootstocks resistant to root-knot nematodes (Meloidogyne spp.) and diseases including Fusarium wilt, Fusarium crown and root rot, Verticillium wilt, bacterial wilt, Southern blight, and sudden wilt have been developed and many are available commercially. New technologies such as transcriptomics, identification of differentially expressed genes, transgene rootstocks, and RNAi silencing are being used in the development of vegetable rootstocks which are resistant to pests, salt tolerant, and heat and cold tolerant. Overall, grafting has proven to be a successful and environmentally safe method for managing root-knot nematodes and soil-borne diseases by reducing infection, disease development, and inoculum build-up in the soil, which is especially important for growth of healthy subsequent crops. © 2021 Society of Chemical Industry.
Topics: Animals; Cucumis sativus; Fusarium; Plant Diseases; Tylenchoidea; Vegetables
PubMed: 34148287
DOI: 10.1002/ps.6512 -
Annual Review of Phytopathology Aug 2020The loss of methyl bromide as a soil fumigant and minimal advances in the development and registration of new chemical fumigants has resulted in a resurgence of interest... (Review)
Review
The loss of methyl bromide as a soil fumigant and minimal advances in the development and registration of new chemical fumigants has resulted in a resurgence of interest in the application of organic amendments (OAs) for soilborne plant pathogen and plant-parasitic nematode management. Significant progress has been made in the characterization of OAs, application of strategies for their use, and elucidation of mechanisms by which they suppress soilborne pests. Nonetheless, their utility is limited by the variability of disease control, expense, and the logistics of introducing them into crop production systems. Recent advances in molecular techniques have led to significant progress in the elucidation of the role of bacteria and fungi and their metabolic products on disease suppression with the addition of OAs. Biosolarization and anaerobic soil disinfestation, developed to manipulate systems and favor beneficial microorganisms to maximize their impact on plant pathogens, are built on a strong historical research foundation in OAs and the physical, chemical, and biological characteristics of disease-suppressive soils. This review focuses on recent applications of OAs and their potential for the management of soilborne plant pathogens and plant-parasitic nematodes, with emphasis primarily on annual fruit and vegetable production systems.
Topics: Animals; Crop Production; Fungi; Nematoda; Soil; Soil Microbiology
PubMed: 32853099
DOI: 10.1146/annurev-phyto-080516-035608 -
Journal of Occupational Medicine and... Oct 2022Fumigants are gaseous pesticides or biocides which eradicate pests by suffocation or poisoning. Worker exposure to fumigants is mainly via inhalation, followed by dermal... (Review)
Review
Fumigants are gaseous pesticides or biocides which eradicate pests by suffocation or poisoning. Worker exposure to fumigants is mainly via inhalation, followed by dermal contact and ingestion, leading to various acute and chronic health effects. Implementation of appropriate workplace controls such as adequate ventilation, training and personal protective equipment ensure that exposure to fumigants are kept to the lowest level as practically possible. In addition, routine medical examinations also allow for doctors to identify and manage possible exposure to fumigants and ascertain workers' fitness to work.While management guidelines after an acute exposure to such fumigants is clear and consistent, the guidelines on routine medical examination for fumigators is sparse. Components of the medical examinations vary according to the fumigant, workers are exposed to and its chronic health effects. Hence, this paper highlights the health hazards of commonly utilised fumigants; Methyl Bromide, Hydrogen Cyanide, Hydrogen Phosphide and Sulfuryl Fluoride; and outlines the guidance for routine medical examinations for exposed fumigators.
PubMed: 36307823
DOI: 10.1186/s12995-022-00361-3 -
The Journal of Asthma : Official... Nov 2020Urban monitors of Methyl bromide (MBr), not typically near application sites, are used to investigate the impact of ambient concentrations on asthma Emergency...
Urban monitors of Methyl bromide (MBr), not typically near application sites, are used to investigate the impact of ambient concentrations on asthma Emergency Department (ED) visits. 4262 ED visits from August to February of 2005 to 2011 in Central and Southern California were selected from California's Office of Statewide Health Planning and Development (OSHPD). A bidirectional-symmetric case-crossover study design using conditional logistic regression model was used to obtain the odds ratio (OR) and 95% confidence interval associated with a 0.01 ppb (interquartile range) increase in MBr. The population sample was comprised of 46.0% male and 53.9% females. Ethnic groups included 32.0% Non-Hispanic White, 23.5% Non-Hispanic Black, and 44.4% Hispanic. Age distribution was between 2 and 5 years old (11.6%), 6 and 18 years old (23.5%), 19 and 40 years old (29.3%), 41 and 64 years old (24.1%), and 65 or older (6.9%). There was a positive association between MBr and asthma ED visits among Non-Hispanic Blacks [OR: 1.065 (95% confidence intervals: 1.019, 1.108)] and Hispanics [OR: 1.107 (95% confidence intervals: 1.043, 1.173)], while Non-Hispanic Whites did not have an association with asthma ED visits. Positive association between MBr and asthma ED visits was found only among 6 to 18 [OR: 1.071 (95% confidence intervals: 1.016, 1.125)] years old. An increase in MBr concentration was found to be associated with an increase of the odds of having asthma ED visits in California among 6 to 18 years old and disproportionately affects Non-Hispanic Blacks and Hispanics over Non-Hispanic Whites.
Topics: Adolescent; Adult; Black or African American; Age Factors; Aged; Air Pollutants; Asthma; California; Child; Child, Preschool; Cross-Over Studies; Emergency Service, Hospital; Environmental Monitoring; Female; Health Status Disparities; Hispanic or Latino; Humans; Hydrocarbons, Brominated; Male; Middle Aged; Odds Ratio; Risk Factors; White People; Young Adult
PubMed: 31311358
DOI: 10.1080/02770903.2019.1645167 -
Insects Jan 2023Invasive snails and flies are major pests of imported orchids, controlled by methyl bromide (MB) fumigation in Korea. We compared the efficacy and phytotoxicity of ethyl...
Invasive snails and flies are major pests of imported orchids, controlled by methyl bromide (MB) fumigation in Korea. We compared the efficacy and phytotoxicity of ethyl formate (EF) and MB on four species of imported orchids using juvenile stages of Achatina fulica and third and fourth instars of Lycoriella mali. EF was as effective as MB. The LCt99 values of EF were 68.1 and 73.1 g h/m3 at 15 °C; and those of MB were 95.9 and 78.4 g h/m3 at 15 °C for A. fulica and L. mali, respectively. In the scale-up trials, EF treatment at 35 g/m3 for 4 h at 15 °C resulted in complete control of both pests. MB treatment based on the current treatment guidelines for imported orchids (48 g/m3, 2 h, at >15 °C) resulted in complete control of L. mali but not of A. fulica. Chlorophyll content and hue values of treated orchids were not affected by EF treatment but significantly changed by MB (p-value < 0.05). All four treated species of orchids died within 30 d of MB treatment, while only one species died from EF treatment. Our results suggest that EF is a potential alternative to MB in phytosanitary treatment of imported orchids.
PubMed: 36661994
DOI: 10.3390/insects14010066 -
The American Journal of Chinese Medicine 2023Franch (RC), has historically been used for the treatment of "Xiao Ke" and "Xia Li" symptoms in China. "Xia Li" is characterized by abdominal pain and diarrhea, which...
Franch (RC), has historically been used for the treatment of "Xiao Ke" and "Xia Li" symptoms in China. "Xia Li" is characterized by abdominal pain and diarrhea, which are similar to the clinical symptoms of ulcerative colitis (UC). For the first time, this study aims to compare the anti-colitis effects of berberine (BBR) and total RC alkaloids (TRCA) and investigate the underlying metabolites and gut microbiota biomarkers. Metabolomics results showed that several colitis-related biomarkers, including lysophosphatidyl ethanolamine, lysophosphatidylcholine, scopolamine-methyl-bromide, N1-methyl-2-pyridone-5-carboxamide, 4-hydroxyretinoic acid, and malic acid, were significantly improved in model mice after BBR and TRCA treatments. High-dose BBR and TRCA treatments reversed the mouse colon shortening caused by dextran sodium sulfate (DSS), alleviated bowel wall swelling, and reduced inflammatory cell infiltration. BBR and TRCA restored the damaged mucosa integrity in colitis mice by upregulating claudin 1 and occludin, preventing colon epithelium apoptosis by inhibiting the cleavage of caspase 3. Additionally, BBR and TRCA significantly decreased the richness of the pathogenic bacteria but increased the abundance of the probiotic . Notably, TRCA exhibited superior anti-colitis effects to those of BBR. Thus, this agent warrants further study and application in the treatment of inflammatory bowel disease in the clinic.
Topics: Animals; Mice; Colitis, Ulcerative; Berberine; Coptis chinensis; Colitis; Microbiota; Colon; Biomarkers; Dextran Sulfate; Disease Models, Animal; Mice, Inbred C57BL
PubMed: 37930330
DOI: 10.1142/S0192415X23500945 -
Steroids Dec 2021Vecuronium bromide (Piperidinium, 1-[(2β,3α,5α,16β,17β)-3,17-bis(acetyloxy)-2-(1-piperidinyl)androstan-16-yl]-1-methyl-, bromide; Norcuron®) has been extensively...
Vecuronium bromide (Piperidinium, 1-[(2β,3α,5α,16β,17β)-3,17-bis(acetyloxy)-2-(1-piperidinyl)androstan-16-yl]-1-methyl-, bromide; Norcuron®) has been extensively used in anesthesiology practice as neuromuscular blocking agent since its launch on the market in 1982. However, a detailed crystallographic and NMR analysis of its advanced synthetic intermediates is still lacking. Hence, with the aim of filling this literature gap, vecuronium bromide was prepared starting from the commercially available 3β-hydroxy-5α-androstan-17-one (epiandrosterone), implementing some modifications to a traditional synthetic procedure. A careful NMR study allowed the complete assignment of the H, C, and N NMR signals of vecuronium bromide and its synthetic intermediates. The structural and stereochemical characterization of 2β,16β-bispiperidino-5α-androstane-3α,17β-diol, the first advanced synthetic intermediate carrying all the stereocenters in the final configuration, was described by means of single-crystal X-ray diffraction and Hirshfeld surface analysis, allowing a detailed conformational investigation.
Topics: Crystallography, X-Ray; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular Structure; Neuromuscular Blocking Agents; Vecuronium Bromide
PubMed: 34655596
DOI: 10.1016/j.steroids.2021.108928