Gaseous detectors are one of the popular particle tracking technologies in high energy physics, and there are multiple applications where the detectors must tolerate outdoor conditions, e.g. in the ...emerging field of muography. Gaseous tracking detectors are attractive choices due to their high efficiency, good resolution and large sensitive area at a reasonable cost and low weight, but to achieve these, the gas system is usually not sealed. Continuous gas flow results gas consumption and thus regular gas cylinder replacement which limits applicability. In this paper we present a practical solution to reduce gas flow to a negligible level, keeping the construction cost-efficient and low weight, by a properly chosen buffer tube at the end of the gas line, which makes the system able to withstand large temperature and pressure fluctuations.
Muography is a novel imaging technology based on particle physics instrumentation to reveal density structure of hill-sized objects. The cosmic muon flux is attenuated while penetrating into the ...ground, thus the differential local flux correlates with the overburden density-length. Underground muography exploits the close-to-zenith flux, while main challenges became portability, low power consumption, and robustness against the out-of-the-laboratory environment. Various fields could benefit from this non-invasive imaging, eg. speleology, mining, archeology, or industry. Portable gaseous tracking detector systems have been designed, built, and successfully used in several underground locations. This paper presents the designed portable muography systems, the main requirements, and measurement campaigns for calibration, natural caves, and cultural heritage.
Muography is a novel imaging technology to reveal density structure of hill-sized objects. The cosmic muons predictably lose their energy and penetrate hundreds of meters into the ground, thus their ...differential local flux correlates with the crossed density-length. The Sakurajima Muography Observatory in Kagoshima, Japan, is the largest muography experiment targeting an active volcano. A set of multilayered gaseous detectors are used to reconstruct the muon tracks, thus by measuring the flux, imaging of the inner part of the volcano become possible. The paper focuses on the technical challenges of such a particle tracking system, the designed multi-wire proportional chambers, and the recent results from the measurements.
We report on cellular actions of the illicit recreational drug gamma-hydroxybutyrate (GHB) in the brain reward area nucleus accumbens. First, we compared the effects of GHB and the GABA(B) receptor ...agonist baclofen. Neither of them affected the membrane currents of medium spiny neurons in rat nucleus accumbens slices. GABAergic and glutamatergic synaptic potentials of medium spiny neurons, however, were reduced by baclofen but not GHB. These results indicate the lack of GHB as well as postsynaptic GABA(B) receptors, and the presence of GHB insensitive presynaptic GABA(B) receptors in medium spiny neurons. In astrocytes GHB induced intracellular Ca(2+) transients, preserved in slices from GABA(B) receptor type 1 subunit knockout mice. The effects of tetrodotoxin, zero added Ca(2+) with/without intracellular Ca(2+) store depletor cyclopiazonic acid or vacuolar H-ATPase inhibitor bafilomycin A1 indicate that GHB-evoked Ca(2+) transients depend on external Ca(2+) and intracellular Ca(2+) stores, but not on vesicular transmitter release. GHB-induced astrocytic Ca(2+) transients were not affected by the GHB receptor-specific antagonist NCS-382, suggesting the presence of a novel NCS-382-insensitive target for GHB in astrocytes. The activation of astrocytes by GHB implies their involvement in physiological actions of GHB. Our findings disclose a novel profile of GHB action in the nucleus accumbens. Here, unlike in other brain areas, GHB does not act on GABA(B) receptors, but activates an NCS-382 insensitive GHB-specific target in a subpopulation of astrocytes. The lack of either post- or presynaptic effects on medium spiny neurons in the nucleus accumbens distinguishes GHB from many drugs and natural rewards with addictive properties and might explain why GHB has only a weak reinforcing capacity.
Abstract We report on cellular actions of the illicit recreational drug γ-hydroxybutyrate (GHB) in the brain reward area nucleus accumbens. First, we compared the effects of GHB and the GABAB ...receptor agonist baclofen. Neither of them affected the membrane currents of medium spiny neurons in rat nucleus accumbens slices. GABAergic and glutamatergic synaptic potentials of medium spiny neurons, however, were reduced by baclofen but not GHB. These results indicate the lack of GHB as well as postsynaptic GABAB receptors, and the presence of GHB insensitive presynaptic GABAB receptors in medium spiny neurons. In astrocytes GHB induced intracellular Ca2+ transients, preserved in slices from GABAB receptor type 1 subunit knockout mice. The effects of tetrodotoxin, zero added Ca2+ with/without intracellular Ca2+ store depletor cyclopiazonic acid or vacuolar H-ATPase inhibitor bafilomycin A1 indicate that GHB-evoked Ca2+ transients depend on external Ca2+ and intracellular Ca2+ stores, but not on vesicular transmitter release. GHB-induced astrocytic Ca2+ transients were not affected by the GHB receptor-specific antagonist NCS-382, suggesting the presence of a novel NCS-382-insensitive target for GHB in astrocytes. The activation of astrocytes by GHB implies their involvement in physiological actions of GHB. Our findings disclose a novel profile of GHB action in the nucleus accumbens. Here, unlike in other brain areas, GHB does not act on GABAB receptors, but activates an NCS-382 insensitive GHB-specific target in a subpopulation of astrocytes. The lack of either post- or presynaptic effects on medium spiny neurons in the nucleus accumbens distinguishes GHB from many drugs and natural rewards with addictive properties and might explain why GHB has only a weak reinforcing capacity.
Detector developments for high performance Muography applications Varga, D.; Nyitrai, G.; Hamar, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Volume:
958
Journal Article
Peer reviewed
Muography allows imaging of large scale objects using cosmic muons. As the observation point needs to be below the object of interest, either the detector is placed underground, and can reveal ...density structures, or, the detector can be on the surface and look sideways, capturing muons closer to the horizon.
As the measurement time is fundamentally limited by the muon flux, long term operation must be achieved with high efficiency. Furthermore, reasonable imaging from a large distance requires good angular resolution. The relevance of addressing the out-of-laboratory environment is demonstrated on the example of a 4 square metre telescope targeting the Sakurajima volcano in Japan.
For open air detectors, the suppression of the low energy (non penetrating) muon background can be reached with a telescope using absorber (scatterer) layers between detector layers with good position resolution. The presented Muography Observation System achieves that using MWPC-s, combined with the relevant servicing systems providing reliable power and gas supply, as well as data acquisition and transfer.
ATP and adenosine are well-known neuroactive compounds. Other nucleotides and nucleosides may also be involved in different brain functions. This paper reports on extracellular concentrations of ...nucleobases and nucleosides (uracil, hypoxanthine, xanthine, uridine, 2′-deoxycytidine, 2′-deoxyuridine, inosine, guanosine, thymidine, adenosine) in response to sustained depolarisation, using in vivo brain microdialysis technique in the rat thalamus. High-potassium solution, the glutamate agonist kainate, and the Na
+/K
+ ATPase blocker ouabain were applied in the perfusate of microdialysis probes and induced release of various purine and pyrimidine nucleosides. All three types of depolarisation increased the level of hypoxanthine, uridine, inosine, guanosine and adenosine. The levels of measured deoxynucleosides (2′-deoxycytidine, 2′-deoxyuridine and thymidine) decreased or did not change, depending on the type of depolarisation. Kainate-induced changes were TTX insensitive, and ouabain-induced changes for inosine, guanosine, 2′-deoxycytidine and 2′-deoxyuridine were TTX sensitive. In contrast, TTX application without depolarisation decreased the extracellular concentrations of hypoxanthine, uridine, inosine, guanosine and adenosine.
Our data suggest that various nucleosides may be released from cells exposed to excessive activity and, thus, support several different lines of research concerning the regulatory roles of nucleosides.
In the present study, we compared in vivo changes of extracellular amino acid levels and nucleotide derivatives to a single ip dose of lindane (10-60 mg/kg) and picrotoxin (5 mg/kg) in the ...hippocampus of halothane anaesthetized rat by microdialysis-coupled HPLC analysis. Brain activity was monitored by EEG. The effects of lindane and picrotoxin on EEG pattern of rats as well as on hippocampal amino acid and nucleotide status were studied in 0-50 min, 50-100 min and 100-150 min periods post-dosing. Significant decreases in Glu and Asp were found after picrotoxin treatment. After 50-100 min post-dosing, hippocampal hypoxanthine and inosine levels increased to both lindane (10 mg/kg) and picrotoxin whereas xanthine and uridine levels increased to picrotoxin, only. Lindane elicited a dose-dependent occurrence of negative spikes accompanied with rhythmic activity at 4-5 Hz. The picrotoxin-induced 4-5 Hz activity did not display negative sharp waves and was accompanied by 10 Hz oscillations.
We report on cellular actions of the illicit recreational drug g-hydroxybutyrate (GHB) in the brain reward area nucleus accumbens. First, we compared the effects of GHB and the GABA sub(B) receptor ...agonist baclofen. Neither of them affected the membrane currents of medium spiny neurons in rat nucleus accumbens slices. GABAergic and glutamatergic synaptic potentials of medium spiny neurons, however, were reduced by baclofen but not GHB. These results indicate the lack of GHB as well as postsynaptic GABA sub(B) receptors, and the presence of GHB insensitive presynaptic GABA sub(B) receptors in medium spiny neurons. In astrocytes GHB induced intracellular Ca super(2+) transients, preserved in slices from GABA sub(B) receptor type 1 subunit knockout mice. The effects of tetrodotoxin, zero added Ca super(2+) with/without intracellular Ca super(2+) store depletor cyclopiazonic acid or vacuolar H-ATPase inhibitor bafilomycin A1 indicate that GHB-evoked Ca super(2+) transients depend on external Ca super(2+) and intracellular Ca super(2+) stores, but not on vesicular transmitter release. GHB-induced astrocytic Ca super(2+) transients were not affected by the GHB receptor-specific antagonist NCS-382, suggesting the presence of a novel NCS-382-insensitive target for GHB in astrocytes. The activation of astrocytes by GHB implies their involvement in physiological actions of GHB. Our findings disclose a novel profile of GHB action in the nucleus accumbens. Here, unlike in other brain areas, GHB does not act on GABA sub(B) receptors, but activates an NCS-382 insensitive GHB-specific target in a subpopulation of astrocytes. The lack of either post- or presynaptic effects on medium spiny neurons in the nucleus accumbens distinguishes GHB from many drugs and natural rewards with addictive properties and might explain why GHB has only a weak reinforcing capacity.
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