The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Ali Hassanzadeh - One of the best experts on this subject based on the ideXlab platform.
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a new method for predicting the heats of combustion of polynitro arene polynitro heteroarene acyclic and cyclic nitramine Nitrate Ester and nitroaliphatic compounds
Journal of Hazardous Materials, 2011Co-Authors: Mohammad Hossein Keshavarz, Bahman Ebrahimi Saatluo, Ali HassanzadehAbstract:A new method is presented for estimating the gross and net heats of combustion of important classes of energetic compounds including polynitro arene, polynitro heteroarene, acyclic and cyclic nitramine, Nitrate Ester and nitroaliphatic compounds. Elemental compositions as well as the presence of some specific polar groups and molecular fragments are important parameters in the new model. The novel method can be easily used for any complex organic compounds with at least one nitro, nitramine or Nitrate functional groups by which the predictions of their heats of combustion by the available methods are inaccurate or difficult. The predicted results show that this method gives reliable predictions of heats of combustion with respect to group additivity method and computed values based on atom-type electrotopological state indices for several energetic compounds where the models can be applied.
Gregory R. J. Thatcher - One of the best experts on this subject based on the ideXlab platform.
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Cognitive Deficits in Rats after Forebrain Cholinergic Depletion are Reversed by a Novel NO Mimetic Nitrate Ester
Neuropsychopharmacology, 2007Co-Authors: Brian M. Bennett, James N. Reynolds, Glen T. Prusky, Robert M. Douglas, Robert J. Sutherland, Gregory R. J. ThatcherAbstract:Many conditions adversely affecting learning, memory, and cognition are associated with reductions in forebrain acetylcholine (ACh), most notably aging and Alzheimer's disease. In the current study, we demonstrate that bilateral depletion of neocortical and hippocampal ACh in rats produces deficits in a spatial learning task and in a recently described, delayed visual matching-to-sample task. Oral administration of the novel Nitrate, GT1061 (4-methyl-5-(2-nitroxyethyl) thiazole HCl), and the acetylcholinEsterase inhibitor, donepezil, reversed the cognitive deficits in both memory tasks in a dose-dependent manner. GT1061 was superior in the delayed matching-to-sample task. GT1061 was absorbed rapidly after oral administration, crossed the blood brain barrier, and achieved brain concentrations that were slightly higher than those found in plasma. The activity of GT1061 was NO mimetic: soluble guanylyl cyclase (sGC) was activated, but selectivity was observed for sGC in the hippocampus relative to the vasculature; and hippocampal levels of phosphorylated ERK1/2, which is a postulated intermediary in the formation of long-term memory, were increased. The beneficial effect on visual and spatial memory task performance supports the concept that stimulating the NO/sGC/cGMP signal transduction system can provide new, effective treatments for cognitive disorders. This approach may be superior to that of current drugs that attempt only to salvage the residual function of damaged cholinergic neurons.
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Cognitive Deficits in Rats after Forebrain Cholinergic Depletion are Reversed by a Novel NO Mimetic Nitrate Ester
Neuropsychopharmacology, 2006Co-Authors: Brian M. Bennett, James N. Reynolds, Glen T. Prusky, Robert M. Douglas, Robert J. Sutherland, Gregory R. J. ThatcherAbstract:Cognitive Deficits in Rats after Forebrain Cholinergic Depletion are Reversed by a Novel NO Mimetic Nitrate Ester
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neuroprotection against ischemic brain injury conferred by a novel Nitrate Ester
Bioorganic & Medicinal Chemistry Letters, 2002Co-Authors: James N. Reynolds, Brian M. Bennett, R J Boegman, Khem Jhamandas, Jodan D Ratz, Sergei I Zavorin, Dan Scutaru, Adina Dumitrascu, Gregory R. J. ThatcherAbstract:Abstract Nitrates exhibit a selectivity of action in different tissue types not fully recognized: in particular, the neuromodulatory and cardiovascular properties can be dissociated. A novel Nitrate showed relatively weak systemic effects, but in the middle cerebral artery occlusion rat model of focal ischemia, reduced the cerebral infarct by 60–70% when administered 4 h after the onset of ischemia.
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a novel Nitrate Ester reverses the cognitive impairment caused by scopolamine in the morris water maze
Neuroreport, 2000Co-Authors: Sheri Smith, Brian M. Bennett, Gregory R. J. Thatcher, Hans C Dringenberg, James N. ReynoldsAbstract:The objective of this study was to test the hypothesis that activation of soluble guanylyl cyclase and increased cGMP formation in the brain would improve task acquisition in cognitively impaired animals. We evaluated the effects of a novel Nitrate Ester, GT 715 (2,3-dinitrooxy-(2,3-bis-nitrooxypropyldisulfanyl)-propane), in scopolamine-induced impairment of task acquisition in the Morris water maze. GT 715 improved task acquisition in scopolamine-pretreated animals in a time- and dose-dependent manner, whereas the prototypical Nitrate Ester, glyceryl triNitrate (GTN), was ineffective. GT 715 also was more effective and more potent than GTN for activation of hippocampal guanylyl cyclase. The results of this study therefore suggest that stimulation of cerebral soluble guanylyl cyclase activity may be an effective strategy to improve learning and memory performance in individuals in whom cognitive abilities are impaired by injury, disease, or ageing.
Thomas P Forbes - One of the best experts on this subject based on the ideXlab platform.
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direct analysis in real time mass spectrometry of potential by products from homemade Nitrate Ester explosive synthesis
Talanta, 2016Co-Authors: Edward Sisco, Thomas P ForbesAbstract:Abstract This work demonstrates the coupling of direct analysis in real time (DART) ionization with time-of-flight mass spectrometry (MS) in an off-axis configuration for the trace detection and analysis of potential partially Nitrated and dimerized by-products of homemade Nitrate Ester explosive synthesis. Five compounds relating to the synthesis of nitroglycerin (NG) and pentaerythritol tetraNitrate (PETN) were examined. Deprotonated ions and adducts with molecular oxygen, nitrite, and Nitrate were observed in the mass spectral responses of these compounds. A global optimum temperature of 350 °C for the by-products investigated here enabled single nanogram to sub nanogram trace detection. Matrix effects were examined through a series of mixtures containing one or more compounds (sugar alcohol precursors, by-products, and/or explosives) across a range of mass loadings. The explosives MS responses experienced competitive ionization in the presence of all by-products. The magnitude of this influence corresponded to both the degree of by-product nitration and the relative mass loading of the by-product to the explosive. This work provides a characterization of potential by-products from homemade Nitrate Ester synthesis, including matrix effects and potential challenges that might arise from the trace detection of homemade explosives (HMEs) containing impurities. Detection and understanding of HME impurities and complex mixtures may provide valuable information for the screening and sourcing of homemade Nitrate Ester explosives.
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rapid detection of sugar alcohol precursors and corresponding Nitrate Ester explosives using direct analysis in real time mass spectrometry
Analyst, 2015Co-Authors: Edward Sisco, Thomas P ForbesAbstract:This work highlights the rapid detection of Nitrate Ester explosives and their sugar alcohol precursors by direct analysis in real time mass spectrometry (DART-MS) using an off-axis geometry. Demonstration of the effect of various parameters, such as ion polarity and in-source collision induced dissociation (CID) on the detection of these compounds is presented. Sensitivity of sugar alcohols and Nitrate Ester explosives was found to be greatest in negative ion mode with sensitivities ranging from hundreds of picograms to hundreds of nanograms, depending on the characteristics of the particular molecule. Altering the in-source CID potential allowed for acquisition of characteristic molecular ion spectra as well as fragmentation spectra. Additional studies were completed to identify the role of different experimental parameters on the sensitivity for these compounds. Variables that were examined included the DART gas stream temperature, the presence of a related compound (i.e., the effect of a precursor on the detection of a Nitrate Ester explosive), incorporation of dopant species and the role of the analysis surface. It was determined that each variable affected the response and detection of both sugar alcohols and the corresponding Nitrate Ester explosives. From this work, a rapid and sensitive method for the detection of individual sugar alcohols and corresponding Nitrate Ester explosives, or mixtures of the two, has been developed, providing a useful tool in the real-world identification of homemade explosives.
Mohammad Hossein Keshavarz - One of the best experts on this subject based on the ideXlab platform.
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a new method for predicting the heats of combustion of polynitro arene polynitro heteroarene acyclic and cyclic nitramine Nitrate Ester and nitroaliphatic compounds
Journal of Hazardous Materials, 2011Co-Authors: Mohammad Hossein Keshavarz, Bahman Ebrahimi Saatluo, Ali HassanzadehAbstract:A new method is presented for estimating the gross and net heats of combustion of important classes of energetic compounds including polynitro arene, polynitro heteroarene, acyclic and cyclic nitramine, Nitrate Ester and nitroaliphatic compounds. Elemental compositions as well as the presence of some specific polar groups and molecular fragments are important parameters in the new model. The novel method can be easily used for any complex organic compounds with at least one nitro, nitramine or Nitrate functional groups by which the predictions of their heats of combustion by the available methods are inaccurate or difficult. The predicted results show that this method gives reliable predictions of heats of combustion with respect to group additivity method and computed values based on atom-type electrotopological state indices for several energetic compounds where the models can be applied.
S Moghaddary - One of the best experts on this subject based on the ideXlab platform.
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predicting the heats of combustion of polynitro arene polynitro heteroarene acyclic and cyclic nitramine Nitrate Ester and nitroaliphatic compounds using bee algorithm and adaptive neuro fuzzy inference system
Chemometrics and Intelligent Laboratory Systems, 2013Co-Authors: Kobra Zarei, Morteza Atabati, S MoghaddaryAbstract:Abstract A new method was developed for prediction of the heats of combustion of important classes of energetic compounds including polynitro arene, polynitro heteroarene, acyclic and cyclic nitramine, Nitrate Ester and nitroaliphatic compounds. A set of 1497 zero- to three-dimensional descriptors was generated for each molecule in the data set. A major problem of modeling is the high dimensionality of the descriptor space; therefore, descriptor selection is one of the most important steps. In this paper, bee algorithm (BA) was used to select the best descriptors. Bee algorithm is a new population-based optimization algorithm, which is derived from the observation of real bees and proposed to feature selection. Four descriptors were selected and used as inputs for adaptive neuro-fuzzy inference system (ANFIS). Squared correlations of coefficients were obtained as 0.9980, 0.9996 and 0.9988 for training, test and validation sets, respectively. In comparison with genetic algorithm (GA)-ANFIS and multiple linear regression (MLR)-ANFIS, the results showed that Bee-ANFIS can be used as a powerful model for prediction of heats of combustion of these compounds.