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The Journal of Physical Chemistry... May 2019The exploration of chemical reactions preceding ignition is essential for the development of ideal hypergolic propellants. Unexpected reaction pathways of a hypergolic...
The exploration of chemical reactions preceding ignition is essential for the development of ideal hypergolic propellants. Unexpected reaction pathways of a hypergolic mixture composed of monomethylhydrazine and nitrogen dioxide are predicted through a cooperative combination of (i) spin-unrestricted ab initio molecular dynamics (AIMD) and (ii) wave packet dynamics of protons. Ensembles of AIMD trajectories reveal a sequence of reaction steps for proton transfer and rupture of the C-N bond. The details of proton transfer are explored by wave packet dynamics on the basis of ab initio potential energy surfaces from AIMD trajectories. The possibility of spontaneous ignition of this hypergolic mixture at room temperature is predicted as a quantized feature of proton-transfer dynamics.
PubMed: 30978025
DOI: 10.1021/acs.jpclett.9b00674 -
Toxicology and Applied Pharmacology Apr 1982
Topics: Animals; Diazepam; Dose-Response Relationship, Drug; Drug Therapy, Combination; Male; Methylhydrazines; Mice; Mice, Inbred ICR; Monomethylhydrazine; Muscimol; Oxazoles; Pyridoxine; Seizures
PubMed: 7089971
DOI: 10.1016/0041-008x(82)90042-4 -
Toxicology Letters Jul 1991Exposure to monomethylhydrazine (MMH), a common rocket propellant, can cause dose-related central nervous system (CNS) disturbances ranging from tremors to tonic-clonic...
Exposure to monomethylhydrazine (MMH), a common rocket propellant, can cause dose-related central nervous system (CNS) disturbances ranging from tremors to tonic-clonic convulsions to death. MMH inhibits gamma-aminobutyric acid (GABA) synthesis in the CNS. Diazepam (BZ) acts at the GABA receptor site, and it is also here that ivermectin (AVM) is pharmacologically active. Mice were injected with 30 mg/kg MMH. Groups of 12 mice each were then given varying doses of AVM (5, 10 and 15 mg/kg), or AVM + BZ combinations (5 mg/kg AVM with 5 mg/kg BZ, 10 mg/kg AVM with 5 mg/kg BZ). Time to first convulsion and time to death were recorded over the next 7 h and all groups were monitored over the next 7 days. Times to convulsion were not altered with AVM alone, but death was significantly prevented with AVM dosages. A treatment of 10 mg/kg AVM with 5 mg/kg BZ resulted in no seizures or deaths.
Topics: Animals; Diazepam; Injections, Intraperitoneal; Ivermectin; Male; Mice; Mice, Inbred ICR; Monomethylhydrazine; Seizures
PubMed: 1853361
DOI: 10.1016/0378-4274(91)90143-t -
Toxicology in Vitro : An International... Oct 2018Hydrazine-based liquid propellants are routinely used for space rocket propulsion, in particular monomethylhydrazine (MMH), although such compounds are highly hazardous....
Hydrazine-based liquid propellants are routinely used for space rocket propulsion, in particular monomethylhydrazine (MMH), although such compounds are highly hazardous. For several years, great efforts were devoted to developing a less hazardous molecule. To explore the toxicological effects of an alternative compound, namely (E)-1,1,4,4-tetramethyl-2-tetrazene (TMTZ), we exposed various cellular animal and human models to this compound and to the reference compound MMH. We observed no cytotoxic effects following exposure to TMTZ in animal, as well as human models. However, although the three animal models were unaffected by MMH, exposure of the human hepatic HepaRG cell model revealed that apoptotic cytotoxic effects were only detectable in proliferative human hepatic HepaRG cells and not in differentiated cells, although major biochemical modifications were uncovered in the latter. The present findings indicate that the metabolic mechanisms of MMH toxicity is close to those described for hydrazine with numerous biochemical alterations induced by mitochondrial disruption, production of radical species, and aminotransferase inhibition. The alternative TMTZ molecule had little impact on cellular viability and proliferation of rodent and human dermic and hepatic cell models. TMTZ did not produce any metabolomic effects and appears to be a promising putative industrial alternative to MMH.
Topics: Aerosol Propellants; Animals; Azo Compounds; Cell Line; Cell Survival; Cricetulus; Fibroblasts; Humans; Metabolomics; Mice; Monomethylhydrazine
PubMed: 29885439
DOI: 10.1016/j.tiv.2018.06.005 -
American Family Physician May 1981
Topics: Amanitins; Antidotes; Cyclopropanes; Gastric Lavage; Glutamine; Humans; Monomethylhydrazine; Muscarine; Muscimol; Mushroom Poisoning; Psilocybin
PubMed: 7234633
DOI: No ID Found -
Dalton Transactions (Cambridge, England... Nov 2021The great interest in aluminium nitride thin films has been attributed to their excellent dielectric, thermal and mechanical properties. Here we present the results of...
The great interest in aluminium nitride thin films has been attributed to their excellent dielectric, thermal and mechanical properties. Here we present the results of amorphous AlN films obtained by atomic layer deposition. We used trimethylaluminum and monomethylhydrazine as the precursors at a deposition temperature of 375-475 °C. The structural and mechanical properties and chemical composition of the synthesized films were investigated in detail by X-ray diffraction, X-ray photoelectron spectroscopy, electron and probe microscopy and nanoindentation. The obtained films were compact and continuous, exhibiting amorphous nature with homogeneous in-depth composition, at an oxygen content of as low as 4 at%. The mechanical properties were comparable to those of AlN films produced by other techniques.
PubMed: 34610072
DOI: 10.1039/d1dt02529e -
Experimental Neurology Aug 1978The toxic derivative of hydrazine, monomethylhydrazine, at a dosage of 10 mg/kg is a potent convulsant, producing tonic-clonic seizures in the cat. In this study the...
The toxic derivative of hydrazine, monomethylhydrazine, at a dosage of 10 mg/kg is a potent convulsant, producing tonic-clonic seizures in the cat. In this study the effects of enforced restraint on susceptibility to MMH-induced seizures was examined in naive animals and in cats prepared neurosurgically with indwelling polygraphic recording electrodes. Using a counterbalanced design, latency to seizure following the intraperitoneal administration of the drug (10 mg/kg) was measured twice in all animals, under restraint and in freely moving conditions. Susceptibility to seizures was significantly decreased under the condition of restraint. Additionally, polygraphic recordings showed that restraint was accompanied by an increased incidence of “synchronous” EEG patterns. These results were not explained by metabolic variables, duration of intertrial interval, or changes in weight. The relationship between observed polygraphic patterns and seizure response is discussed in terms of the physiological alterations attendant upon restraint.
Topics: Animals; Cats; Electroencephalography; Female; Male; Methylhydrazines; Monomethylhydrazine; Restraint, Physical; Seizures
PubMed: 680066
DOI: 10.1016/0014-4886(78)90187-5 -
The Journal of Pharmacy and Pharmacology Oct 1995Following administration of the anticancer agent, procarbazine, or one of its metabolites, monomethylhydrazine, to rats, activities of monoamine oxidases A and B (MAO A...
Following administration of the anticancer agent, procarbazine, or one of its metabolites, monomethylhydrazine, to rats, activities of monoamine oxidases A and B (MAO A and MAO B) and of semicarbazide-sensitive amine oxidase (SSAO) were measured ex-vivo. Both compounds were found to be potent inhibitors of SSAO in tissue homogenates, exhibiting ID50 values in most tissues of approximately 8 mg kg-1 (procarbazine) and 0.08 mg kg-1 (monomethylhydrazine). Concurrent dose-dependent inhibition of MAO activities did not occur. However, in liver, potentiation of MAO B activity, to 140% of that in controls, was apparent following monomethyl-hydrazine and this effect was independent of the drug dose. Both compounds produced a dose-dependent potentiation of MAO A in brown adipose tissue, the elevation being more pronounced following monomethylhydrazine, with activity rising to 350% of that in control homogenates. In a parallel in-vitro study, monomethylhydrazine was without effect on MAO A in brown adipose tissue homogenates. By perfusing the SSAO substrate, benzylamine, through the isolated mesenteric arterial bed of the rat, it was found that pretreatment of animals with procarbazine or monomethylhydrazine reduced metabolism of this amine by a similar degree as had been determined ex-vivo in blood vessel homogenates. The results presented suggest that these compounds would be suitable for use as selective inhibitors in pharmacological examinations of SSAO function in isolated tissues and organs.
Topics: Amine Oxidase (Copper-Containing); Animals; Antineoplastic Agents; Benzylamines; Enzyme Inhibitors; Isoenzymes; Male; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Monomethylhydrazine; Procarbazine; Rats; Rats, Wistar; Semicarbazides; Sensitivity and Specificity
PubMed: 8583353
DOI: 10.1111/j.2042-7158.1995.tb05751.x