431 research outputs found

    Waste Management in Russia

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    The field of waste management in Russia demonstrates the consequences of stifling political opposition. Legislation censors environmentalists and activists who seek to reform current waste management practices, even as local politicians financially reward companies for dumping waste into deteriorating landfills. This article reviews current waste management practices in Russia and the effects of such practices on the Russian populace. It outlines the various protests and other forms of civic engagement that have taken place in response to inadequate waste management, and the government's repression of such responses using the "foreign agent" law. Finally, the article examines the corruption in Russia's waste management system and explores why reform of this sector is unlikely to occur

    LY 294002 inhibits adenosine receptor activation by a mechanism independent of effects on PI-3 kinase or casein kinase II

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    Adenosine reduces both evoked and spontaneous calcium-dependent acetylcholine (ACh) release through a mechanism downstream of calcium entry at amphibian motor nerve endings (Silinsky EM. J Physiol 1984; 346: 243-6). LY 294002 (2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one), an inhibitor of both phosphoinositide-3 kinase (PI-3 kinase) and casein kinase II, has been reported to increase spontaneous ACh release reflected in miniature endplate potential (MEPP) frequencies independently of intraterminal calcium at the frog neuromuscular junction (Rizzoli SO, Betz WJ. J Neurosci 2002; 22: 10680-). It has been suggested that the increase in MEPP frequency caused by LY 294002, is mediated through an action on synaptotagmins, vesicle associated calcium sensors believed to trigger synaptic vesicle exocytosis. We thus examined the effects of adenosine on MEPP frequencies and evoked ACh release reflected as endplate potentials (EPPs) in order to determine if the presumed calcium-independent ACh release is affected by adenosine. We also wanted to determine if PI-3 kinase or casein kinase II is involved in mediating or modulating the inhibitory effects of adenosine. To these ends, we examined the effects of adenosine in the presence of LY 294002, wortmannin (a highly selective the PI-3 kinase inhibitor), or DRB (5,6-dichlorobenzimidazole riboside, an inhibitor of casein kinase II). LY 294002 reduced the sensitivity of both MEPP frequencies and the nerve-evoked calcium dependent EPPs to adenosine. The occlusive effects of LY 294002 on the actions of adenosine on MEPPs and EPPs were overcome by increasing adenosine concentration. Neither wortmannin nor DRB had any effect on the sensitivity of the EPPs to adenosine indicating that neither PI-3 kinase nor casein kinase II inhibition mediates the reduction in motor-nerve terminal sensitivity to adenosine produced by LY 294002. The results indicate a competitive relationship between LY 294002 and adenosine at A1 receptors at the frog neuromuscular junction. This effect is independent of the previously described effects of LY 294002 on the exocytotic process, and is also independent of PI-3 kinase or casein kinase II

    Vessels For Growth

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    This written report supports the creative thesis entitled Vessels of Growth. My  work in clay and mixed media references southern culture with particular interest in the tobacco barns and buildings of the southern landscape because of the stories and activities they contain. These barns and outbuildings contrast with our modern lifestyle, yet they are still a visual part of our contemporary life. My work imparts the poetic, emotional qualities of these physical forms while revealing the beauty that occurs with their decay. These buildings are often surrounded by crops of tobacco, cotton, soybeans or corn. My work uses the imagery of the southern landscape as subject and incorporates the crops and plants of this region. These vessels constructed of clay are inspired by the barns and the land on which these buildings are supported. I will also describe my research into the agriculture and agricultural architecture of this region, particularly the thriving cotton, corn and tobacco crops.  M.F.A

    Pre- and postsynaptic actions of ATP on neurotransmission in rat submandibular ganglia

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    The pre- and postsynaptic actions of exogenously applied ATP were investigated in intact and dissociated parasympathetic neurotics of rat submandibular ganglia. Nerve-evoked excitatory postsynaptic potentials (EPSPs) were not inhibited by the purinergic receptor antagonists, suramin and pyridoxal-phosphate-6-azophenyl-2 ' ,4 ' -disulphonic acid (PPADS), or the desensitising agonist, alpha,beta -methylene ATP. In contrast. EPSPs were abolished by the nicotinic acetylcholine receptor antagonists, hexamethonium and mecamylamine. Focal application of ATP (100 muM) had no effect on membrane potential of the postsynaptic neurone or on the amplitude of spontaneous EPSPs. Taken together, these results suggest the absence of functional purinergic (P2) receptors on the postganglionic neurone in situ. In contrast, focally applied ATP (100 muM) reversibly inhibited nerve-evoked EPSPs. Similarly, bath application of the non-hydrolysable analogue of ATP, ATP gammaS, reversibly depressed EPSPs amplitude, The inhibitory effects of ATP and ATP gammaS on nerve-evoked transmitter release were antagonised by bath application of either PPADS or suramin, suggesting ATP activates a presynaptic P2 purinoceptor to inhibit acetylcholine release from preganglionic nerves in the submandibular ganglia. In acutely dissociated postganglionic neurotics from rat submandibular ganglia. focal application of ATP (100 LM) evoked an inward current and subsequent excitatory response and action potential firing, which was reversibly inhibited by PPADS (10 muM). The expression of P2X purinoceptors in wholemount and dissociated submandibular ganglion neurones was examined using polyclonal antibodies raised against the extracellular domain of six P2X purinoceptor subtypes (P2X(1-6)). In intact wholemount preparations, only the P2X(5) purinoceptor subtype was found to be expressed in the submandibular ganglion neurones and no P2X immunoreactivity was detected in the nerve fibres innervating the ganglion. Surprisingly, in dissociated submandibular ganglion neurones, high levels of P2X(2) and P2X(4) purinoceptors immunoreactivity were found on the cell surface. This increase in expression of P2X(2) and P2X(4) purinoceptors in dissociated submandibular neurones could explain the increased responsiveness of the neurotics to exogenous ATP. We conclude that disruption of ganglionic transmission in vivo by either nerve damage or synaptic blockade may up-regulate P2X expression or availability and alter neuronal excitability. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved

    P2 receptors are involved in the mediation of motivation-related behavior

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    The importance of purinergic signaling in the intact mesolimbic–mesocortical circuit of the brain of freely moving rats is reviewed. In the rat, an endogenous ADP/ATPergic tone reinforces the release of dopamine from the axon terminals in the nucleus accumbens as well as from the somatodendritic region of these neurons in the ventral tegmental area, as well as the release of glutamate, probably via P2Y1 receptor stimulation. Similar mechanisms may regulate the release of glutamate in both areas of the brain. Dopamine and glutamate determine in concert the activity of the accumbal GABAergic, medium-size spiny neurons thought to act as an interface between the limbic cortex and the extrapyramidal motor system. These neurons project to the pallidal and mesencephalic areas, thereby mediating the behavioral reaction of the animal in response to a motivation-related stimulus. There is evidence that extracellular ADP/ATP promotes goal-directed behavior, e.g., intention and feeding, via dopamine, probably via P2Y1 receptor stimulation. Accumbal P2 receptor-mediated glutamatergic mechanisms seem to counteract the dopaminergic effects on behavior. Furthermore, adaptive changes of motivation-related behavior, e.g., by chronic succession of starvation and feeding or by repeated amphetamine administration, are accompanied by changes in the expression of the P2Y1 receptor, thought to modulate the sensitivity of the animal to respond to certain stimuli

    P2 receptor-mediated modulation of neurotransmitter release—an update

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    Presynaptic nerve terminals are equipped with a number of presynaptic auto- and heteroreceptors, including ionotropic P2X and metabotropic P2Y receptors. P2 receptors serve as modulation sites of transmitter release by ATP and other nucleotides released by neuronal activity and pathological signals. A wide variety of P2X and P2Y receptors expressed at pre- and postsynaptic sites as well as in glial cells are involved directly or indirectly in the modulation of neurotransmitter release. Nucleotides are released from synaptic and nonsynaptic sites throughout the nervous system and might reach concentrations high enough to activate these receptors. By providing a fine-tuning mechanism these receptors also offer attractive sites for pharmacotherapy in nervous system diseases. Here we review the rapidly emerging data on the modulation of transmitter release by facilitatory and inhibitory P2 receptors and the receptor subtypes involved in these interactions

    DAG tales: the multiple faces of diacylglycerol—stereochemistry, metabolism, and signaling

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