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The Journal of Physical Chemistry. A Jul 2020Experimental, numerical, and theoretical studies are performed to understand the explosive thermal decomposition of monomethylhydrazine/argon mixtures. Ignition delays...
Experimental, numerical, and theoretical studies are performed to understand the explosive thermal decomposition of monomethylhydrazine/argon mixtures. Ignition delays of concentrated MMH/Ar mixtures (20-30%) have been measured behind a reflected shock wave around 1000 K and 1 atm. Although several detailed chemical kinetic models have predictive abilities for diluted and highly diluted mixtures, none of them showed predictive for concentrated mixtures. A new kinetic model is proposed, in which numerous rate constants and thermochemical data are reassessed based on theoretical calculations, with the purpose to determine whether, or to what extent, trends derived from diluted or highly diluted MMH/Ar mixtures can explain observations in concentrated MMH mixtures. The present kinetic model is found to predict speciation experimental profiles in diluted MMH/Ar mixtures and is a significant improvement in predicting the induction delays of concentrated MMH/Ar mixtures.
PubMed: 32603112
DOI: 10.1021/acs.jpca.0c03144 -
Aerospace Medicine Dec 1967
Topics: Aerospace Medicine; Animals; Dogs; Erythrocytes; Guinea Pigs; Hemoglobins; Humans; Hydrazines; In Vitro Techniques; Male; Methemoglobin; Rabbits; Rats
PubMed: 6076551
DOI: No ID Found -
American Industrial Hygiene Association... 1970
Topics: Animals; Ataxia; Blood Chemical Analysis; Body Weight; Cyanosis; Diarrhea; Dogs; Environmental Exposure; Environmental Health; Eye Manifestations; Female; Fossil Fuels; Gases; Haplorhini; Hemolysis; Hydrazines; Male; Methemoglobin; Methylation; Mice; Mortality; Rats; Respiration; Respiratory System; Seizures; Species Specificity; Time Factors
PubMed: 4992844
DOI: 10.1080/0002889708506313 -
Analytical Chemistry Apr 1997A novel integrated acoustooptic tunable filter (IAOTF) has been developed. This tunable filter is based on the Bragg interactions between waveguide and surface acoustic...
Determination of monomethylhydrazine with a high-throughput, all-fiber near-infrared spectrometer based on an integrated acoustooptic tunable filter and an erbium-doped fiber amplifier.
A novel integrated acoustooptic tunable filter (IAOTF) has been developed. This tunable filter is based on the Bragg interactions between waveguide and surface acoustic waves. Compared to (bulk) AOTF, its advantage include all-fiber construction, smaller size, narrower spectral resolution (1.7 nm), higher diffraction efficiency (37%), and lower rf power requirement (150 mW). A relatively narrow spectral tuning range (about 80 nm) is the only drawback for this integrated tunable filter. However, this disadvantage was overcome by judiciously using the filter for measurements in which its tuning range is coincident with the light source and also with absorption bands of analytes. In fact, an all-fiber, compact, high-throughput near-infrared spectrophotometer has been successfully constructed by synergistic use of this integrated AOTF and the erbium-doped fiber amplifier (EDFA), which has been shown to provide high intensity and wide spectral band-width in the near-infrared region from 1500 to 1600 nm. This spectral region is particularly useful for the determination of samples which have O-H and/or N-H groups. The all-fiber nature, compactness, high throughput, and high sensitivity of this spectrophotometer make it particularly suitable for on-line and real-time detection of trace gases in hostile environments, including leak detection of monomethylhydrazine (at a limit of detection of 191 ppm), which is often used as the hypergolic propellant for the space shuttle thruster systems.
Topics: Acoustics; Erbium; Filtration; Monomethylhydrazine; Spectrophotometry, Atomic; Spectrophotometry, Infrared
PubMed: 9105182
DOI: 10.1021/ac960919u -
Cancer Letters Jan 1992Consumption of false morel (Gyromitra esculenta Fr.) has been associated not only with acute poisoning, but also with a carcinogenic risk. The hydrolysis of...
Consumption of false morel (Gyromitra esculenta Fr.) has been associated not only with acute poisoning, but also with a carcinogenic risk. The hydrolysis of acetaldehyde-N-methyl-N-formylhydrazone (gyromitrin, the main toxic component of false morel) results in the formation of the methylating agents N-methyl-N-formylhydrazine (MFH) and N-methylhydrazine (MMH) (by further hydrolysis of MFH). This study reports traces of N-7-methylguanine (N7MeGu) in liver DNA from mice and a rat treated with gyromitrin. After repeated administration of MMH, N7MeGu was identified in rat liver DNA. In mice exposed to MMH according to a dosing scheme identical to that reported to induce tumours in this species, O6-methylguanine was present in liver and kidney DNA. The results indicate that a relatively low carcinogenic risk is associated with false morel consumption. The risk may be greater in individuals with a decreased detoxification rate (acetylation) of MFH, in whom larger amounts of MMH are formed from gyromitrin.
Topics: Acetaldehyde; Alkylating Agents; Animals; Carcinogens; DNA Damage; Liver; Methylation; Mice; Monomethylhydrazine; Rats
PubMed: 1730140
DOI: 10.1016/0304-3835(92)90175-u -
The Journal of Physical Chemistry. A May 2020Methylamine radicals (CHNH) and amino radicals (NH) are major products in the early pyrolysis/ignition of monomethylhydrazine (CHNHNH). kinetics of thermal...
Methylamine radicals (CHNH) and amino radicals (NH) are major products in the early pyrolysis/ignition of monomethylhydrazine (CHNHNH). kinetics of thermal decomposition of CHNH radicals was analyzed by RRKM master equation simulations. It was found that β-scission of the methyl H-atom from CHNH radicals is predominant and fast enough to induce subsequent H-abstraction reactions in CHNHNH to trigger ignition. Consequently, the kinetics of H-abstraction reactions from CHNHNH by H-atoms was further investigated. It was found that the energy barriers for abstraction of the central amine H-atom, two terminal amine H-atoms, and methyl H-atoms are 4.16, 2.95, 5.98, and 8.50 kcal mol, respectively. In units of cm molecule s, the corresponding rate coefficients were found to be = 9.63 × 10 exp(-154.2/), = 2.04 × 10 exp(104.1/), = 1.13 × 10 exp(-416.3/), and = 2.41 × 10 exp(-870.5/), respectively, in the 290-2500 K temperature range. The results reveal that abstraction of the terminal amine H-atom to form -CHNHNH radicals is the dominant channel among the different abstraction channels. At 298 K, the total theoretical H-abstraction rate coefficient, calculated with no adjustable parameters, is 8.16 × 10 cm molecule s, which is in excellent agreement with Vaghjiani's experimental observation of (7.60 ± 1.14) × 10 cm molecule s ( 1997, 101, 4167-4171, DOI: 10.1021/jp964044z).
PubMed: 32299215
DOI: 10.1021/acs.jpca.0c02389 -
American Industrial Hygiene Association... 1965
Topics: Animals; Blood Chemical Analysis; Colorimetry; Hydrazines; In Vitro Techniques; Rats
PubMed: 5865322
DOI: 10.1080/00028896509342767 -
Toxicology and Applied Pharmacology Sep 1966
Topics: Animals; Behavior, Animal; Haplorhini; Hydrazines; Injections, Intraperitoneal; Learning
PubMed: 4961360
DOI: 10.1016/0041-008x(66)90134-7 -
The Journal of Emergency Medicine Feb 2005Mushrooms are ubiquitous in nature. They are an important source of nutrition, however, certain varieties contain chemicals that can be highly toxic to humans.... (Review)
Review
Mushrooms are ubiquitous in nature. They are an important source of nutrition, however, certain varieties contain chemicals that can be highly toxic to humans. Industrially cultivated mushrooms are historically very safe, whereas foraging for mushrooms or accidental ingestion of mushrooms in the environment can result in serious illness and death. The emergency department is the most common site of presentation for patients suffering from acute mushroom poisoning. Although recognition can be facilitated by identification of a characteristic toxidrome, the presenting manifestations can be variable and have considerable overlap with more common and generally benign clinical syndromes. The goal of this two-part article is to review the knowledge base on this subject and provide information that will assist the clinician in the early consideration, diagnosis and treatment of mushroom poisoning. Part I reviewed the epidemiology and demographics of mushroom poisoning, the physical characteristics of the most toxic varieties, the classification of the toxic species, and presented an overview of the cyclopeptide-containing mushroom class. Part II is focused on the presentation of the other classes of toxic mushrooms along with an up-to-date review of the most recently identified poisonous varieties.
Topics: 2,2'-Dipyridyl; Adult; Child; Disulfiram; Emergency Medicine; Enzyme Inhibitors; Gastroenteritis; Hallucinogens; Humans; Indoles; Irritants; Isoxazoles; Monomethylhydrazine; Muscarine; Mushroom Poisoning; Mycotoxins
PubMed: 15707814
DOI: 10.1016/j.jemermed.2004.08.019 -
European Journal of Emergency Medicine... Apr 2005Pyridoxine (vitamin B6) is a co-factor in many enzymatic pathways involved in amino acid metabolism: the main biologically active form is pyridoxal 5-phosphate.... (Review)
Review
Pyridoxine (vitamin B6) is a co-factor in many enzymatic pathways involved in amino acid metabolism: the main biologically active form is pyridoxal 5-phosphate. Pyridoxine has been used as an antidote in acute intoxications, including isoniazid overdose, Gyromitra mushroom or false morrel (monomethylhydrazine) poisoning and hydrazine exposure. It is also recommended as a co-factor to improve the conversion of glyoxylic acid into glycine in ethylene glycol poisoning. Other indications are recommended by some sources (for example crimidine poisoning, zipeprol and theophylline-induced seizures, adjunct to d-penicillamine chelation), without significant supporting data. The value of pyridoxine or its congener metadoxine as an agent for hastening ethanol metabolism or improving vigilance in acute alcohol intoxication is controversial. This paper reviews the various indications of pyridoxine in clinical toxicology and the supporting literature. The potential adverse effects of excessive pyridoxine dosage will also be summarized.
Topics: Animals; Antidotes; Ethanol; Ethylene Glycol; Humans; Hydrazines; Isoniazid; Mushroom Poisoning; Poisoning; Pyridoxine; Pyrimidines
PubMed: 15756083
DOI: 10.1097/00063110-200504000-00007