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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 -
Journal of the Air & Waste Management... Jun 2022Alfalfa hay that was grown on a field treated with a methyl bromide and chloropicrin pesticide (at a 98/2 weight ratio) resulted in animal sickness, posing a disposal...
Alfalfa hay that was grown on a field treated with a methyl bromide and chloropicrin pesticide (at a 98/2 weight ratio) resulted in animal sickness, posing a disposal issue for the harvested feed. In consideration of disposal options, emissions and residues from burning treated and untreated alfalfa hay were sampled and analyzed to provide data for an assessment of potential health and environmental effects. Treated alfalfa hay was tested in parallel with untreated alfalfa in a controlled laboratory combustion facility. Results showed that about half of the bromine and chlorine in the treated hay was emitted and the remaining was retained in the ash. The alfalfa hay burned poorly, with modified combustion efficiencies, the ratio of CO to CO + CO, below 0.89. The emission factor for PM was statistically higher for the untreated versus treated alfalfa but the PAHs were doubled in the treated alfalfa. The treated alfalfa had significantly more emissions of polychorinated dibenzodioxin/dibenzofuran than the untreated alfalfa by a factor of 10, but less polybrominated dibenzodioxin/dibenzofuran. The high Br concentration in the treated alfalfa biomass may have resulted in formation and emission of mixed halogen compounds which were unable to be analyzed for lack of standards. Comparison of volatile organic compound emissions were unremarkable with the exception of MeBr where emissions from the treated alfalfa were over 300 times higher than the untreated biomass. The potential complications due to emissions and permitting of an open burn or contained incinerator left options for landfilling and feedstock blending for handling the treated alfalfa. : This paper illustrates the issues agricultural managers must deal with concerning the combustive disposal of contaminated crops. A method is presented whereby combustion of contaminated crops can be assessed for their suitability for disposal by open air or enclosed burning.
Topics: Air Pollutants; Biomass; Bromides; Carbon Dioxide; Crops, Agricultural; Dibenzofurans; Hydrocarbons, Brominated
PubMed: 34895080
DOI: 10.1080/10962247.2021.2013343 -
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 -
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 -
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 -
Insects Nov 2020At a time when there is much talk of reducing pesticide use and the implementation of integrated pest management, mainly in fields and glass-houses, it is appropriate to... (Review)
Review
At a time when there is much talk of reducing pesticide use and the implementation of integrated pest management, mainly in fields and glass-houses, it is appropriate to consider how cereals in storage are handled and what measures are taken to protect them against insects and other pests. For decades, the use of various synthetic pesticides has been the basis for the proper and long-term storage of cereals, primarily free of insects and mites, but also fungi and their mycotoxins and rodents. However, due to the registered negative effects of synthetic pesticides, such as dichloro-diphenyl-trihloroethane (DDT) or methyl bromide, on human health and the environment, and the appearance of resistance to, e.g., malathion, researchers have been looking for new acceptable control measures. Due to the proven and published non-acceptable data regarding synthetic pesticide effects, a combination of physical, mechanical, and biological measures with the minimal use of synthetic pesticides, under the name of integrated pest management, have been promoted. These combinations include high and low temperatures; the removal of dockages; and the application of pheromones, diatomaceous earth, and natural compounds from various plants, as well as inert gases, predators, and parasites. A ban of any synthetic pesticide usage is currently being considered, which emphasizes the fact that protection should only be performed by measures that do not leave harmful residues. However, the facts show that the application of physical, mechanical, and/or biological measures, besides the fact that they are not necessarily efficient, is very demanding because more knowledge and experience is required, as well as better equipment, greater financial investment, and awareness raising not only for agricultural producers and storage keepers, but also for consumers. In order to use these measures, which are less hazardous to humans and the environment, it is necessary to adapt regulations not only to speed up the registration protocols of low-risk pesticides, but also to prescribe criteria for placing agricultural products on the market, as well as quality standards, i.e., the permitted number of present insects, in addition to their parts in certain types of food. Additionally, we should be aware of control measures for protecting novel food and other non-traditional foods. It is important to continue to combine different protection measures, namely integrated pest management, until all of the other new procedures that must be carried out during the period of storing cereals and other products are clear, in order to ensure the best quality of final products for consumers.
PubMed: 33260599
DOI: 10.3390/insects11120846 -
Journal of Occupational Health Jan 2021In this study, we aimed to establish a method for quantifying bromide ions (Br ) in blood and urine using gas chromatograph-mass spectrometer (GC-MS) equipped with a...
OBJECTIVES
In this study, we aimed to establish a method for quantifying bromide ions (Br ) in blood and urine using gas chromatograph-mass spectrometer (GC-MS) equipped with a headspace sampler, for biological monitoring of workers exposed to methyl bromide.
METHODS
Samples were mixed with dimethyl sulfate, and Br ions were detected using GC-MS with a headspace sampler. The validity of the proposed method was evaluated based on most of the US FDA guidance. The values obtained were compared with reference values by analysis using Seronorm Trace Elements Whole Blood L-1 RUO.
RESULTS
The calibration curve showed good linearity in the Br concentration range of 0.1-20.0 mg/L, and the coefficient of determination R value was >.999. Intraday and interday accuracy values were 99.3%-103.1% and 97.4%-101.8%, respectively. The measured and reference values of Seronorm were concordant. Herein, eight urine and serum samples of workers were analyzed; the samples' Br concentrations were known. The correlation coefficients of urine and serum samples were 0.97 and 0.96, respectively, and results were consistent.
CONCLUSIONS
This study established a simple and rapid method for the determination of Br concentration in biological samples using GC-MS with a headspace sampler. Moreover, it can be used for biological monitoring of occupational exposure to methyl bromide and for the determination of Br concentration in a wide range of biological samples.
Topics: Biological Monitoring; Bromides; Gas Chromatography-Mass Spectrometry; Humans; Hydrocarbons, Brominated; Occupational Exposure; Reference Values; Reproducibility of Results
PubMed: 34587337
DOI: 10.1002/1348-9585.12274 -
The Journal of International Medical... Oct 2022Methyl bromide is a pre-plant soil fumigant that is widely used to control nematodes, insects, and fungi in farmlands. Methyl bromide enters the human body through...
Methyl bromide is a pre-plant soil fumigant that is widely used to control nematodes, insects, and fungi in farmlands. Methyl bromide enters the human body through dermal absorption or inhalation and can damage the respiratory, nervous, circulatory, urinary, and other systems. A 62-year-old man who had inhaled a large amount of methyl bromide was admitted to our department. He presented with respiratory failure and pink foamy sputum. He was started on dexamethasone, alanyl glutamine, sulbactam, furosemide, vitamin B, mouse nerve growth factor, and other treatments, and mechanical ventilation and continuous venovenous hemodiafiltration (CVVHF) were performed daily. He subsequently developed coagulopathy because of the CVVHF, for which protamine, recombinant human brain natriuretic peptide, and albumin were administered intravenously. Notably, the patient developed sustained anuria and eventually died owing to multiple organ failure; specifically, failure of the brain, heart, lungs, and kidneys. This report presents the diagnosis, clinical course, management, and prognosis of a patient who was treated at our hospital for severe methyl bromide poisoning.
Topics: Acute Kidney Injury; Albumins; Animals; Anuria; Dexamethasone; Furosemide; Glutamine; Humans; Hydrocarbons, Brominated; Male; Mice; Middle Aged; Natriuretic Peptide, Brain; Nerve Growth Factors; Protamines; Soil; Sulbactam; Vitamins
PubMed: 36250482
DOI: 10.1177/03000605221122619