Miniature excitatory synaptic currents in cultured hippocampal neurons.

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Finch, D M; Fisher, R S; Jackson, M B

1990-06-04

We performed patch clamp recordings in the whole cell mode from cultured embryonic mouse hippocampal neurons. In bathing solutions containing tetrodotoxin (TTX), the cells showed spontaneous inward currents (SICs) ranging in size from 1 to 100 pA. Several observations indicated that the SICs were miniature excitatory synaptic currents mediated primarily by non-NMDA (N-methyl-D-aspartate) excitatory amino acid receptors: the rising phase of SICs was fast (1 ms to half amplitude at room temperature) and smooth, suggesting unitary events. The SICs were blocked by the broad-spectrum glutamate receptor antagonist gamma-D-glutamylglycine (DGG), but not by the selective NMDA-receptor antagonist D-2-amino-5-phosphonovaleric acid (5-APV). SICs were also blocked by desensitizing concentrations of quisqualate. Incubating cells in tetanus toxin, which blocks exocytotic transmitter release, eliminated SICs. The presence of SICs was consistent with the morphological arrangement of glutamatergic innervation in the cell cultures demonstrated immunohistochemically. Spontaneous outward currents (SOCs) were blocked by bicuculline and presumed to be mediated by GABAA receptors. This is consistent with immunohistochemical demonstration of GABAergic synapses. SIC frequency was increased in a calcium dependent manner by bathing the cells in a solution high in K+, and application of the dihydropyridine L-type calcium channel agonist BAY K 8644 increased the frequency of SICs. Increases in SIC frequency produced by high K+ solutions were reversed by Cd2+ and omega-conotoxin GVIA, but not by the selective L-type channel antagonist nimodipine. This suggested that presynaptic L-type channels were in a gating mode that was not blocked by nimodipine, and/or that another class of calcium channel makes a dominant contribution to excitatory transmitter release.

The Effects of GABAergic Polarity Changes on Episodic Neural Network Activity in Developing Neural Systems

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Wilfredo Blanco

2017-09-01

Full Text Available Early in development, neural systems have primarily excitatory coupling, where even GABAergic synapses are excitatory. Many of these systems exhibit spontaneous episodes of activity that have been characterized through both experimental and computational studies. As development progress the neural system goes through many changes, including synaptic remodeling, intrinsic plasticity in the ion channel expression, and a transformation of GABAergic synapses from excitatory to inhibitory. What effect each of these, and other, changes have on the network behavior is hard to know from experimental studies since they all happen in parallel. One advantage of a computational approach is that one has the ability to study developmental changes in isolation. Here, we examine the effects of GABAergic synapse polarity change on the spontaneous activity of both a mean field and a neural network model that has both glutamatergic and GABAergic coupling, representative of a developing neural network. We find some intuitive behavioral changes as the GABAergic neurons go from excitatory to inhibitory, shared by both models, such as a decrease in the duration of episodes. We also find some paradoxical changes in the activity that are only present in the neural network model. In particular, we find that during early development the inter-episode durations become longer on average, while later in development they become shorter. In addressing this unexpected finding, we uncover a priming effect that is particularly important for a small subset of neurons, called the “intermediate neurons.” We characterize these neurons and demonstrate why they are crucial to episode initiation, and why the paradoxical behavioral change result from priming of these neurons. The study illustrates how even arguably the simplest of developmental changes that occurs in neural systems can present non-intuitive behaviors. It also makes predictions about neural network behavioral changes

Interplay between glucose and leptin signalling determines the strength of GABAergic synapses at POMC neurons.

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Lee, Dong Kun; Jeong, Jae Hoon; Chun, Sung-Kun; Chua, Streamson; Jo, Young-Hwan

2015-03-26

Regulation of GABAergic inhibitory inputs and alterations in POMC neuron activity by nutrients and adiposity signals regulate energy and glucose homeostasis. Thus, understanding how POMC neurons integrate these two signal molecules at the synaptic level is important. Here we show that leptin's action on GABA release to POMC neurons is influenced by glucose levels. Leptin stimulates the JAK2-PI3K pathway in both presynaptic GABAergic terminals and postsynaptic POMC neurons. Inhibition of AMPK activity in presynaptic terminals decreases GABA release at 10 mM glucose. However, postsynaptic TRPC channel opening by the PI3K-PLC signalling pathway in POMC neurons enhances spontaneous GABA release via activation of presynaptic MC3/4 and mGlu receptors at 2.5 mM glucose. High-fat feeding blunts AMPK-dependent presynaptic inhibition, whereas PLC-mediated GABAergic feedback inhibition remains responsive to leptin. Our data indicate that the interplay between glucose and leptin signalling in glutamatergic POMC neurons is critical for determining the strength of inhibitory tone towards POMC neurons.

Interplay between glucose and leptin signaling determines the strength of GABAergic synapses at POMC neurons

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Lee, Dong Kun; Jeong, Jae Hoon; Chun, Sung-Kun; Chua, Streamson; Jo, Young-Hwan

2015-01-01

Regulation of GABAergic inhibitory inputs and alterations in POMC neuron activity by nutrients and adiposity signals regulate energy and glucose homeostasis. Thus, understanding how POMC neurons integrate these two signal molecules at the synaptic level is important. Here we show that leptin’s action on GABA release to POMC neurons is influenced by glucose levels. Leptin stimulates the JAK2-PI3K pathway in both presynaptic GABAergic terminals and postsynaptic POMC neurons. Inhibition of AMPK activity in presynaptic terminals decreases GABA release at 10 mM glucose. However, postsynaptic TRPC channel opening by the PI3K-PLC signaling pathway in POMC neurons enhances spontaneous GABA release via activation of presynaptic MC3/4 and mGlu receptors at 2.5 mM glucose. High-fat feeding blunts AMPK-dependent presynaptic inhibition, whereas PLC-mediated GABAergic feedback inhibition remains responsive to leptin. Our data indicate that the interplay between glucose and leptin signaling in glutamatergic POMC neurons is critical for determining the strength of inhibitory tone towards POMC neurons. PMID:25808323

Low-frequency electrical stimulation enhances the effectiveness of phenobarbital on GABAergic currents in hippocampal slices of kindled rats.

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Asgari, Azam; Semnanian, Saeed; Atapour, Nafiseh; Shojaei, Amir; Moradi-Chameh, Homeira; Ghafouri, Samireh; Sheibani, Vahid; Mirnajafi-Zadeh, Javad

2016-08-25

Low frequency stimulation (LFS) has been proposed as a new approach in the treatment of epilepsy. The anticonvulsant mechanism of LFS may be through its effect on GABAA receptors, which are the main target of phenobarbital anticonvulsant action. We supposed that co-application of LFS and phenobarbital may increase the efficacy of phenobarbital. Therefore, the interaction of LFS and phenobarbital on GABAergic inhibitory post-synaptic currents (IPSCs) in kindled and control rats was investigated. Animals were kindled by electrical stimulation of basolateral amygdala in a semi rapid manner (12 stimulations/day). The effect of phenobarbital, LFS and phenobarbital+LFS was investigated on GABAA-mediated evoked and miniature IPSCs in the hippocampal brain slices in control and fully kindled animals. Phenobarbital and LFS had positive interaction on GABAergic currents. In vitro co-application of an ineffective pattern of LFS (100 pulses at afterdischarge threshold intensity) and a sub-threshold dose of phenobarbital (100μM) which had no significant effect on GABAergic currents alone, increased the amplitude and area under curve of GABAergic currents in CA1 pyramidal neurons of hippocampal slices significantly. Interestingly, the sub-threshold dose of phenobarbital potentiated the GABAergic currents when applied on the hippocampal slices of kindled animals which received LFS in vivo. Post-synaptic mechanisms may be involved in observed interactions. Obtained results implied a positive interaction between LFS and phenobarbital through GABAA currents. It may be suggested that a combined therapy of phenobarbital and LFS may be a useful manner for reinforcing the anticonvulsant action of phenobarbital. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

GABAergic Mechanisms in Schizophrenia

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de Jonge, Jeroen C; Vinkers, Christiaan H; Hulshoff Pol, Hilleke E

2017-01-01

Schizophrenia is a psychiatric disorder characterized by hallucinations, delusions, disorganized thinking, and impairments in cognitive functioning. Evidence from postmortem studies suggests that alterations in cortical γ-aminobutyric acid (GABAergic) neurons contribute to the clinical features...... of schizophrenia. In vivo measurement of brain GABA levels using magnetic resonance spectroscopy (MRS) offers the possibility to provide more insight into the relationship between problems in GABAergic neurotransmission and clinical symptoms of schizophrenia patients. This study reviews and links alterations...... in the GABA system in postmortem studies, animal models, and human studies in schizophrenia. Converging evidence implicates alterations in both presynaptic and postsynaptic components of GABAergic neurotransmission in schizophrenia, and GABA may thus play an important role in the pathophysiology...

Live-Cell, Label-Free Identification of GABAergic and Non-GABAergic Neurons in Primary Cortical Cultures Using Micropatterned Surface

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Kono, Sho; Kushida, Takatoshi; Hirano-Iwata, Ayumi; Niwano, Michio; Tanii, Takashi

2016-01-01

Excitatory and inhibitory neurons have distinct roles in cortical dynamics. Here we present a novel method for identifying inhibitory GABAergic neurons from non-GABAergic neurons, which are mostly excitatory glutamatergic neurons, in primary cortical cultures. This was achieved using an asymmetrically designed micropattern that directs an axonal process to the longest pathway. In the current work, we first modified the micropattern geometry to improve cell viability and then studied the axon length from 2 to 7 days in vitro (DIV). The cell types of neurons were evaluated retrospectively based on immunoreactivity against GAD67, a marker for inhibitory GABAergic neurons. We found that axons of non-GABAergic neurons grow significantly longer than those of GABAergic neurons in the early stages of development. The optimal threshold for identifying GABAergic and non-GABAergic neurons was evaluated to be 110 μm at 6 DIV. The method does not require any fluorescence labelling and can be carried out on live cells. The accuracy of identification was 98.2%. We confirmed that the high accuracy was due to the use of a micropattern, which standardized the development of cultured neurons. The method promises to be beneficial both for engineering neuronal networks in vitro and for basic cellular neuroscience research. PMID:27513933

Regulation of Substantia Nigra Pars Reticulata GABAergic Neuron Activity by H2O2 via Flufenamic Acid-Sensitive Channels and KATP Channels

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Lee, Christian R.; Witkovsky, Paul; Rice, Margaret E.

2011-01-01

Substantia nigra pars reticulata (SNr) GABAergic neurons are key output neurons of the basal ganglia. Given the role of these neurons in motor control, it is important to understand factors that regulate their firing rate and pattern. One potential regulator is hydrogen peroxide (H2O2), a reactive oxygen species that is increasingly recognized as a neuromodulator. We used whole-cell current clamp recordings of SNr GABAergic neurons in guinea-pig midbrain slices to determine how H2O2 affects the activity of these neurons and to explore the classes of ion channels underlying those effects. Elevation of H2O2 levels caused an increase in the spontaneous firing rate of SNr GABAergic neurons, whether by application of exogenous H2O2 or amplification of endogenous H2O2 through inhibition of glutathione peroxidase with mercaptosuccinate. This effect was reversed by flufenamic acid (FFA), implicating transient receptor potential (TRP) channels. Conversely, depletion of endogenous H2O2 by catalase, a peroxidase enzyme, decreased spontaneous firing rate and firing precision of SNr neurons, demonstrating tonic control of firing rate by H2O2. Elevation of H2O2 in the presence of FFA revealed an inhibition of tonic firing that was prevented by blockade of ATP-sensitive K+ (KATP) channels with glibenclamide. In contrast to guinea-pig SNr neurons, the dominant effect of H2O2 elevation in mouse SNr GABAergic neurons was hyperpolarization, indicating a species difference in H2O2-dependent regulation. Thus, H2O2 is an endogenous modulator of SNr GABAergic neurons, acting primarily through presumed TRP channels in guinea-pig SNr, with additional modulation via KATP channels to regulate SNr output. PMID:21503158

Acute morphine alters GABAergic transmission in the central amygdala during naloxone-precipitated morphine withdrawal: role of cyclic AMP

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Michal eBajo

2014-06-01

Full Text Available The central amygdala (CeA plays an important role in opioid addiction. Therefore, we examined the effects of naloxone-precipitated morphine withdrawal (WD on GABAergic transmission in rat CeA neurons using whole-cell recordings with naloxone in the bath. The basal frequency of miniature inhibitory postsynaptic currents (mIPSCs increased in CeA neurons from WD compared to placebo rats. Acute morphine (10 M had mixed effects (> 20% change from baseline on mIPSCs in placebo and WD rats. In most CeA neurons (64% from placebo rats, morphine significantly decreased mIPSC frequency and amplitude. In 32% of placebo neurons, morphine significantly increased mIPSC amplitudes but had no effect on mIPSC frequency. In WD rats, acute morphine significantly increased mIPSC frequency but had no effect on mIPSC amplitude in 41% of CeA neurons. In 45% of cells, acute morphine significantly decreased mIPSC frequency and amplitude. Pre-treatment with the cyclic AMP inhibitor (R-adenosine, cyclic 3’,5’-(hydrogenphosphorothioate triethylammonium (RP, prevented acute morphine-induced potentiation of mIPSCs. Pre-treatment of slices with the Gi/o G-protein subunit inhibitor pertussis toxin (PTX did not prevent the acute morphine-induced enhancement or inhibition of mIPSCs. PTX and RP decreased basal mIPSC frequencies and amplitudes only in WD rats. The results suggest that inhibition of GABAergic transmission in the CeA by acute morphine is mediated by PTX-insensitive mechanisms, although PTX-sensitive mechanisms cannot be ruled out for non-morphine responsive cells; by contrast, potentiation of GABAergic transmission is mediated by activated cAMP signaling that also mediates the increased basal GABAergic transmission in WD rats. Our data indicate that during the acute phase of WD, the CeA opioid and GABAergic systems undergo neuroadaptative changes conditioned by a previous chronic morphine exposure and dependence.

Traumatic Brain Injury Increases Cortical Glutamate Network Activity by Compromising GABAergic Control.

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Cantu, David; Walker, Kendall; Andresen, Lauren; Taylor-Weiner, Amaro; Hampton, David; Tesco, Giuseppina; Dulla, Chris G

2015-08-01

Traumatic brain injury (TBI) is a major risk factor for developing pharmaco-resistant epilepsy. Although disruptions in brain circuitry are associated with TBI, the precise mechanisms by which brain injury leads to epileptiform network activity is unknown. Using controlled cortical impact (CCI) as a model of TBI, we examined how cortical excitability and glutamatergic signaling was altered following injury. We optically mapped cortical glutamate signaling using FRET-based glutamate biosensors, while simultaneously recording cortical field potentials in acute brain slices 2-4 weeks following CCI. Cortical electrical stimulation evoked polyphasic, epileptiform field potentials and disrupted the input-output relationship in deep layers of CCI-injured cortex. High-speed glutamate biosensor imaging showed that glutamate signaling was significantly increased in the injured cortex. Elevated glutamate responses correlated with epileptiform activity, were highest directly adjacent to the injury, and spread via deep cortical layers. Immunoreactivity for markers of GABAergic interneurons were significantly decreased throughout CCI cortex. Lastly, spontaneous inhibitory postsynaptic current frequency decreased and spontaneous excitatory postsynaptic current increased after CCI injury. Our results suggest that specific cortical neuronal microcircuits may initiate and facilitate the spread of epileptiform activity following TBI. Increased glutamatergic signaling due to loss of GABAergic control may provide a mechanism by which TBI can give rise to post-traumatic epilepsy. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Subtypes of GABAergic neurons project axons in the neocortex

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Shigeyoshi Higo

2009-11-01

Full Text Available γ-aminobutyric acid (GABAergic neurons in the neocortex have been regarded as interneurons and speculated to modulate the activity of neurons locally. Recently, however, several experiments revealed that neuronal nitric oxide synthase (nNOS-positive GABAergic neurons project cortico-cortically with long axons. In this study, we illustrate Golgi-like images of the nNOS-positive GABAergic neurons using a nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d reaction and follow the emanating axon branches in cat brain sections. These axon branches projected cortico-cortically with other non-labeled arcuate fibers, contra-laterally via the corpus callosum and anterior commissure. The labeled fibers were not limited to the neocortex but found also in the fimbria of the hippocampus. In order to have additional information on these GABAergic neuron projections, we investigated green fluorescent protein (GFP-labeled GABAergic neurons in GAD67-Cre knock-in / GFP Cre-reporter mice. GFP-labeled axons emanate densely, especially in the fimbria, a small number in the anterior commissure, and very sparsely in the corpus callosum. These two different approaches confirm that not only nNOS-positive GABAergic neurons but also other subtypes of GABAergic neurons project long axons in the cerebral cortex and are in a position to be involved in information processing.

Stationary and non-stationary occurrences of miniature end plate potentials are well described as stationary and non-stationary Poisson processes in the mollusc Navanax inermis.

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Cappell, M S; Spray, D C; Bennett, M V

1988-06-28

Protractor muscles in the gastropod mollusc Navanax inermis exhibit typical spontaneous miniature end plate potentials with mean amplitude 1.71 +/- 1.19 (standard deviation) mV. The evoked end plate potential is quantized, with a quantum equal to the miniature end plate potential amplitude. When their rate is stationary, occurrence of miniature end plate potentials is a random, Poisson process. When non-stationary, spontaneous miniature end plate potential occurrence is a non-stationary Poisson process, a Poisson process with the mean frequency changing with time. This extends the random Poisson model for miniature end plate potentials to the frequently observed non-stationary occurrence. Reported deviations from a Poisson process can sometimes be accounted for by the non-stationary Poisson process and more complex models, such as clustered release, are not always needed.

Hilar GABAergic interneuron activity controls spatial learning and memory retrieval.

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Yaisa Andrews-Zwilling

Full Text Available Although extensive research has demonstrated the importance of excitatory granule neurons in the dentate gyrus of the hippocampus in normal learning and memory and in the pathogenesis of amnesia in Alzheimer's disease (AD, the role of hilar GABAergic inhibitory interneurons, which control the granule neuron activity, remains unclear.We explored the function of hilar GABAergic interneurons in spatial learning and memory by inhibiting their activity through Cre-dependent viral expression of enhanced halorhodopsin (eNpHR3.0--a light-driven chloride pump. Hilar GABAergic interneuron-specific expression of eNpHR3.0 was achieved by bilaterally injecting adeno-associated virus containing a double-floxed inverted open-reading frame encoding eNpHR3.0 into the hilus of the dentate gyrus of mice expressing Cre recombinase under the control of an enhancer specific for GABAergic interneurons. In vitro and in vivo illumination with a yellow laser elicited inhibition of hilar GABAergic interneurons and consequent activation of dentate granule neurons, without affecting pyramidal neurons in the CA3 and CA1 regions of the hippocampus. We found that optogenetic inhibition of hilar GABAergic interneuron activity impaired spatial learning and memory retrieval, without affecting memory retention, as determined in the Morris water maze test. Importantly, optogenetic inhibition of hilar GABAergic interneuron activity did not alter short-term working memory, motor coordination, or exploratory activity.Our findings establish a critical role for hilar GABAergic interneuron activity in controlling spatial learning and memory retrieval and provide evidence for the potential contribution of GABAergic interneuron impairment to the pathogenesis of amnesia in AD.

Accumulation of GABAergic neurons, causing a focal ambient GABA gradient, and downregulation of KCC2 are induced during microgyrus formation in a mouse model of polymicrogyria.

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Wang, Tianying; Kumada, Tatsuro; Morishima, Toshitaka; Iwata, Satomi; Kaneko, Takeshi; Yanagawa, Yuchio; Yoshida, Sachiko; Fukuda, Atsuo

2014-04-01

Although focal cortical malformations are considered neuronal migration disorders, their formation mechanisms remain unknown. We addressed how the γ-aminobutyric acid (GABA)ergic system affects the GABAergic and glutamatergic neuronal migration underlying such malformations. A focal freeze-lesion (FFL) of the postnatal day zero (P0) glutamic acid decarboxylase-green fluorescent protein knock-in mouse neocortex produced a 3- or 4-layered microgyrus at P7. GABAergic interneurons accumulated around the necrosis including the superficial region during microgyrus formation at P4, whereas E17.5-born, Cux1-positive pyramidal neurons outlined the GABAergic neurons and were absent from the superficial layer, forming cell-dense areas in layer 2 of the P7 microgyrus. GABA imaging showed that an extracellular GABA level temporally increased in the GABAergic neuron-positive area, including the necrotic center, at P4. The expression of the Cl(-) transporter KCC2 was downregulated in the microgyrus-forming GABAergic and E17.5-born glutamatergic neurons at P4; these cells may need a high intracellular Cl(-) concentration to induce depolarizing GABA effects. Bicuculline decreased the frequency of spontaneous Ca(2+) oscillations in these microgyrus-forming cells. Thus, neonatal FFL causes specific neuronal accumulation, preceded by an increase in ambient GABA during microgyrus formation. This GABA increase induces GABAA receptor-mediated Ca(2+) oscillation in KCC2-downregulated microgyrus-forming cells, as seen in migrating cells during early neocortical development.

Hilar GABAergic Interneuron Activity Controls Spatial Learning and Memory Retrieval

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Andrews-Zwilling, Yaisa; Gillespie, Anna K.; Kravitz, Alexxai V.; Nelson, Alexandra B.; Devidze, Nino; Lo, Iris; Yoon, Seo Yeon; Bien-Ly, Nga; Ring, Karen; Zwilling, Daniel; Potter, Gregory B.; Rubenstein, John L. R.; Kreitzer, Anatol C.; Huang, Yadong

2012-01-01

Background Although extensive research has demonstrated the importance of excitatory granule neurons in the dentate gyrus of the hippocampus in normal learning and memory and in the pathogenesis of amnesia in Alzheimer's disease (AD), the role of hilar GABAergic inhibitory interneurons, which control the granule neuron activity, remains unclear. Methodology and Principal Findings We explored the function of hilar GABAergic interneurons in spatial learning and memory by inhibiting their activity through Cre-dependent viral expression of enhanced halorhodopsin (eNpHR3.0)—a light-driven chloride pump. Hilar GABAergic interneuron-specific expression of eNpHR3.0 was achieved by bilaterally injecting adeno-associated virus containing a double-floxed inverted open-reading frame encoding eNpHR3.0 into the hilus of the dentate gyrus of mice expressing Cre recombinase under the control of an enhancer specific for GABAergic interneurons. In vitro and in vivo illumination with a yellow laser elicited inhibition of hilar GABAergic interneurons and consequent activation of dentate granule neurons, without affecting pyramidal neurons in the CA3 and CA1 regions of the hippocampus. We found that optogenetic inhibition of hilar GABAergic interneuron activity impaired spatial learning and memory retrieval, without affecting memory retention, as determined in the Morris water maze test. Importantly, optogenetic inhibition of hilar GABAergic interneuron activity did not alter short-term working memory, motor coordination, or exploratory activity. Conclusions and Significance Our findings establish a critical role for hilar GABAergic interneuron activity in controlling spatial learning and memory retrieval and provide evidence for the potential contribution of GABAergic interneuron impairment to the pathogenesis of amnesia in AD. PMID:22792368

GABAergic projections to the oculomotor nucleus in the goldfish (Carassius auratus

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M. Angeles eLuque

2011-02-01

Full Text Available The mammalian oculomotor nucleus receives a strong -aminobutyric acid (GABAergic synaptic input, whereas such projections have rarely been reported in fish. In order to determine whether this synaptic organization is preserved across vertebrates, we investigated the GABAergic projections to the oculomotor nucleus in the goldfish by combining retrograde transport of biotin dextran amine, injected into the antidromically identified oculomotor nucleus, and GABA immunohistochemistry. The main source of GABAergic afferents to the oculomotor nucleus was the ipsilateral anterior octaval nucleus, with only a few, if any, GABAergic neurons being located in the contralateral tangential and descending nuclei of the octaval column. In mammals there is a nearly exclusive ipsilateral projection from vestibular neurons to the oculomotor nucleus via GABAergic inhibitory inputs; thus, the vestibulooculomotor GABAergic circuitry follows a plan that appears to be shared throughout the vertebrate phylogeny. The second major source of GABAergic projections was the rhombencephalic reticular formation, primarily from the medial area but, to a lesser extent, from the inferior area. A few GABAergic oculomotor projecting neurons were also observed in the ipsilateral nucleus of the medial longitudinal fasciculus. The GABAergic projections from neurons located in both the reticular formation surrounding the abducens nucleus and the nucleus of the medial reticular formation have primarily been related to the control of saccadic eye movements. Finally, all retrogradely labeled internuclear neurons of the abducens nucleus, and neurons in the cerebellum (close to the caudal lobe, were negative for GABA. These data suggest that the vestibuloocular and saccadic inhibitory GABAergic systems appear early in vertebrate phylogeny to modulate the firing properties of the oculomotor nucleus motoneurons.

Cortical GABAergic excitation contributes to epileptic activities around human glioma

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Pallud, Johan; Varlet, Pascale; Cresto, Noemie; Baulac, Michel; Duyckaerts, Charles; Kourdougli, Nazim; Chazal, Geneviève; Devaux, Bertrand; Rivera, Claudio; Miles, Richard; Capelle, Laurent; Huberfeld, Gilles

2015-01-01

Rationale Diffuse brain gliomas induce seizures in a majority of patients. As in most epileptic disorders, excitatory glutamatergic mechanisms are involved in the generation of epileptic activities in the neocortex surrounding gliomas. However, chloride homeostasis is known to be perturbed in glial tumor cells. Thus the contribution of GABAergic mechanisms which depend on intracellular chloride and which are defective or pro-epileptic in other structural epilepsies merits closer study. Objective We studied in neocortical slices from the peritumoral security margin resected around human brain gliomas, the occurrence, networks, cells and signaling basis of epileptic activities. Results Postoperative glioma tissue from 69% of patients spontaneously generated interictal-like discharges. These events were synchronized, with a high frequency oscillation signature, in superficial layers of neocortex around glioma areas with tumor infiltration. Interictal-like events depended on both glutamatergic transmission and on depolarizing GABAergic signaling. About 65% of pyramidal cells were depolarized by GABA released by interneurons. This effect was related to perturbations in Chloride homeostasis, due to changes in expression of chloride co-transporters: KCC2 was reduced and expression of NKCC1 increased. Ictal-like activities were initiated by convulsant stimuli exclusively in these epileptogenic areas. Conclusions Epileptic activities are sustained by excitatory effects of GABA in the peritumoral human neocortex, as in temporal lobe epilepsies. Glutamate and GABA signaling are involved in oncogenesis and chloride homeostasis is perturbed. These same factors, induce an imbalance between synaptic excitatory and inhibition underly epileptic discharges in tumor patients. PMID:25009229

Long-range GABAergic connections distributed throughout the neocortex and their possible function

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Nobuaki eTamamaki

2010-12-01

Full Text Available Features and functions of long range GABAergic projection neurons in the developing cerebral cortex have been reported previously, although until now their significance in the adult cerebral cortex has remained uncertain. The septo-hippocampal circuit is one exception – in this system, long range mature GABAergic projection neurons have been well analyzed and their contribution to the generation of theta-oscillatory behavior in the hippocampus has been documented. To have a clue to the function of the GABAergic projection neurons in the neocortex, we view the long range GABAergic projections those participating in the cortico-cortical, cortico-fugal, and afferent projections in the cerebral cortex. Then, we consider the possibility that the GABAergic projection neurons are involved in the generation, modification, and/or synchronization of oscillations in mature neocortical neuron activity. When markers that identify the GABAergic projection neurons are examined in anatomical and developmental studies, it is clear that neuronal NO synthetase (nNOS-immunoreactivity can readily identify GABAergic projection fibers (i.e. those longer than 1.5 mm. To elucidate the role of the GABAergic projection neurons in the neocortex, it will be necessary to clarify the network constructed by nNOS-positive GABAergic projection neurons and their postsynaptic targets. Thus, our long-range goals will be to label and manipulate (including deleting the GABAergic projection neurons using genetic tools driven by a nNOS promoter. We recognize that this may be a complex endeavor, as most excitatory neurons in the murine neocortex express nNOS transiently. Nevertheless, additional studies characterizing long range GABAergic projection neurons will have great value to the overall understanding of mature cortical function.

Localization of the brainstem GABAergic neurons controlling paradoxical (REM sleep.

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Emilie Sapin

Full Text Available Paradoxical sleep (PS is a state characterized by cortical activation, rapid eye movements and muscle atonia. Fifty years after its discovery, the neuronal network responsible for the genesis of PS has been only partially identified. We recently proposed that GABAergic neurons would have a pivotal role in that network. To localize these GABAergic neurons, we combined immunohistochemical detection of Fos with non-radioactive in situ hybridization of GAD67 mRNA (GABA synthesis enzyme in control rats, rats deprived of PS for 72 h and rats allowed to recover after such deprivation. Here we show that GABAergic neurons gating PS (PS-off neurons are principally located in the ventrolateral periaqueductal gray (vlPAG and the dorsal part of the deep mesencephalic reticular nucleus immediately ventral to it (dDpMe. Furthermore, iontophoretic application of muscimol for 20 min in this area in head-restrained rats induced a strong and significant increase in PS quantities compared to saline. In addition, we found a large number of GABAergic PS-on neurons in the vlPAG/dDPMe region and the medullary reticular nuclei known to generate muscle atonia during PS. Finally, we showed that PS-on neurons triggering PS localized in the SLD are not GABAergic. Altogether, our results indicate that multiple populations of PS-on GABAergic neurons are distributed in the brainstem while only one population of PS-off GABAergic neurons localized in the vlPAG/dDpMe region exist. From these results, we propose a revised model for PS control in which GABAergic PS-on and PS-off neurons localized in the vlPAG/dDPMe region play leading roles.

Inward rectifier K+ channel and T-type Ca2+ channel contribute to enhancement of GABAergic transmission induced by β1-adrenoceptor in the prefrontal cortex.

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Luo, Fei; Zheng, Jian; Sun, Xuan; Tang, Hua

2017-02-01

The functions of prefrontal cortex (PFC) are sensitive to norepinephrine (NE). Endogenously released NE influences synaptic transmission through activation of different subtypes of adrenergic receptors in PFC including α 1 , α 2 , β 1 or β 2 -adrenoceptor. Our recent study has revealed that β 1 -adrenoceptor (β 1 -AR) activation modulates glutamatergic transmission in the PFC, whereas the roles of β 1 -AR in GABAergic transmission are elusive. In the current study, we probed the effects of the β 1 -AR agonist dobutamine (Dobu) on GABAergic transmission onto pyramidal neurons in the PFC of juvenile rats. Dobu increased both the frequency and amplitude of miniature IPSCs (mIPSCs). Ca 2+ influx through T-type voltage-gated Ca 2+ channel was required for Dobu-enhanced mIPSC frequency. We also found that Dobu facilitated GABA release probability and the number of releasable vesicles through regulating T-type Ca 2+ channel. Dobu depolarized GABAergic fast-spiking (FS) interneurons with no effects on the firing rate of action potentials (APs) of interneurons. Dobu-induced depolarization of FS interneurons required inward rectifier K + channel (Kir). Our results suggest that Dobu increase GABA release via inhibition of Kir, which further depolarizes FS interneurons resulting in Ca 2+ influx via T-type Ca 2+ channel. Copyright © 2016 Elsevier Inc. All rights reserved.

GABAergic circuit dysfunctions in neurodevelopmental disorders

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Bidisha eChattopadhyaya

2012-05-01

Full Text Available GABAergic interneurons control neuronal excitability, integration, and plasticity. Further, they regulate the generation of temporal synchrony and oscillatory behavior among networks of pyramidal neurons. Such oscillations within and across neural systems are believed to serve various complex functions, such as perception, movement initiation, and memory. Alterations in the development of GABAergic circuits have been implicated in various brain diseases with neurodevelopmental origin. Here, we highlight recent studies suggesting a role for alterations of GABA transmission in the pathophysiology of two neurodevelopmental diseases, schizophrenia and autism. We further discuss how manipulations of GABA signaling may be used for novel therapeutic interventions.

Spontaneous body movements in spatial cognition

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Sergiu eTcaci Popescu

2012-05-01

Full Text Available People often perform spontaneous body movements during spatial tasks such as giving complex directions or orienting themselves on maps. How are these spontaneous gestures related to spatial problem-solving? We measured spontaneous movements during a perspective-taking task inspired by map reading. Analyzing the motion data to isolate rotation and translation components of motion in specific geometric relation to the task, we found out that most participants executed spontaneous miniature rotations of the head that were significantly related to the main task parameter. These head rotations were as if participants were trying to align themselves with the orientation on the map either in the image plane or on the ground plane, but with tiny amplitudes, typically below 1% of the actual movements. Our results are consistent with a model of sensorimotor prediction driving spatial reasoning. The efference copy of planned movements triggers this prediction mechanism. The movements themselves may then be mostly inhibited; the small spontaneous gestures that we measure are the visible traces of these planned but inhibited actions.

Role of tonic GABAergic currents during pre- and early postnatal rodent development

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Werner eKilb

2013-09-01

Full Text Available In the last three decades it became evident that the GABAergic system plays an essential role for the development of the central nervous system, by influencing the proliferation of neuronal precursors, neuronal migration and differentiation, as well as by controlling early activity patterns and thus formation of neuronal networks. GABA controls neuronal development via depolarizing membrane responses upon activation of ionotropic GABA receptors. However, many of these effects occur before the onset of synaptic GABAergic activity and thus require the presence of extrasynaptic tonic currents in neuronal precursors and immature neurons. This review summarizes our current knowledge about the role of tonic GABAergic currents during early brain development. In this review we compare the temporal sequence of the expression and functional relevance of different GABA receptor subunits, GABA synthesizing enzymes and GABA transporters. We also refer to other possible endogenous agonists of GABAA receptors. In addition, we describe functional consequences mediated by the GABAergic system during early developmental periods and discuss current models about the origin of extrasynaptic GABA and/or other endogenous GABAergic agonists during early developmental states. Finally, we present evidence that tonic GABAergic activity is also critically involved in the generation of physiological as well as pathophysiological activity patterns before and after the establishment of functional GABAergic synaptic connections.

Retinoic acid functions as a key GABAergic differentiation signal in the basal ganglia.

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Christina Chatzi

2011-04-01

Full Text Available Although retinoic acid (RA has been implicated as an extrinsic signal regulating forebrain neurogenesis, the processes regulated by RA signaling remain unclear. Here, analysis of retinaldehyde dehydrogenase mutant mouse embryos lacking RA synthesis demonstrates that RA generated by Raldh3 in the subventricular zone of the basal ganglia is required for GABAergic differentiation, whereas RA generated by Raldh2 in the meninges is unnecessary for development of the adjacent cortex. Neurospheres generated from the lateral ganglionic eminence (LGE, where Raldh3 is highly expressed, produce endogenous RA, which is required for differentiation to GABAergic neurons. In Raldh3⁻/⁻ embryos, LGE progenitors fail to differentiate into either GABAergic striatal projection neurons or GABAergic interneurons migrating to the olfactory bulb and cortex. We describe conditions for RA treatment of human embryonic stem cells that result in efficient differentiation to a heterogeneous population of GABAergic interneurons without the appearance of GABAergic striatal projection neurons, thus providing an in vitro method for generation of GABAergic interneurons for further study. Our observation that endogenous RA is required for generation of LGE-derived GABAergic neurons in the basal ganglia establishes a key role for RA signaling in development of the forebrain.

GABAergic Mechanisms in Schizophrenia: Linking Postmortem and In Vivo Studies

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de Jonge, Jeroen C.; Vinkers, Christiaan H.; Hulshoff Pol, Hilleke E.; Marsman, Anouk

2017-01-01

Schizophrenia is a psychiatric disorder characterized by hallucinations, delusions, disorganized thinking, and impairments in cognitive functioning. Evidence from postmortem studies suggests that alterations in cortical γ-aminobutyric acid (GABAergic) neurons contribute to the clinical features of schizophrenia. In vivo measurement of brain GABA levels using magnetic resonance spectroscopy (MRS) offers the possibility to provide more insight into the relationship between problems in GABAergic neurotransmission and clinical symptoms of schizophrenia patients. This study reviews and links alterations in the GABA system in postmortem studies, animal models, and human studies in schizophrenia. Converging evidence implicates alterations in both presynaptic and postsynaptic components of GABAergic neurotransmission in schizophrenia, and GABA may thus play an important role in the pathophysiology of schizophrenia. MRS studies can provide direct insight into the GABAergic mechanisms underlying the development of schizophrenia as well as changes during its course. PMID:28848455

GABAergic Mechanisms in Schizophrenia: Linking Postmortem and In Vivo Studies

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Jeroen C. de Jonge

2017-08-01

Full Text Available Schizophrenia is a psychiatric disorder characterized by hallucinations, delusions, disorganized thinking, and impairments in cognitive functioning. Evidence from postmortem studies suggests that alterations in cortical γ-aminobutyric acid (GABAergic neurons contribute to the clinical features of schizophrenia. In vivo measurement of brain GABA levels using magnetic resonance spectroscopy (MRS offers the possibility to provide more insight into the relationship between problems in GABAergic neurotransmission and clinical symptoms of schizophrenia patients. This study reviews and links alterations in the GABA system in postmortem studies, animal models, and human studies in schizophrenia. Converging evidence implicates alterations in both presynaptic and postsynaptic components of GABAergic neurotransmission in schizophrenia, and GABA may thus play an important role in the pathophysiology of schizophrenia. MRS studies can provide direct insight into the GABAergic mechanisms underlying the development of schizophrenia as well as changes during its course.

GABAergic systems in the vestibular nucleus and their contribution to vestibular compensation.

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Gliddon, Catherine M; Darlington, Cynthia L; Smith, Paul F

2005-01-01

GABA and the GABAA and GABAB receptors play a pivotal role in the coordination of the central vestibular pathways. The commissural inhibition, which exists between the two vestibular nucleus complexes (VNCs) and which is responsible for enhancing the dynamic sensitivity of VNC neurons to head acceleration, is known to be substantially mediated by GABA acting on GABAA and GABAB receptors. After unilateral vestibular deafferentation (UVD), the large asymmetry in spontaneous resting activity between the two VNCs is reinforced and exacerbated by the GABAergic interaction between the ipsilateral and contralateral sides. Although it has been suggested that reduced GABAergic inhibition of the ipsilateral VNC may be partially responsible for the recovery of resting activity that underlies vestibular compensation of the static symptoms of UVD, at present there are few data available to test this hypothesis systematically. There is some evidence that GABA concentrations change in the ipsilateral VNC during the development of compensation; however, it is unclear whether these changes relate to GABA release or to metabolic pools of GABA. Most biochemical studies of GABA receptors have been conducted at the gene expression level. Therefore, it is unclear whether changes in the receptor protein also occur, although the most recent data suggest that changes in GABAA and GABAB receptor density in the VNC are unlikely. The few radioligand binding data relate to GABAA receptors with benzodiazepine binding sites only. A decrease in the sensitivity of ipsilateral VNC neurons from compensated animals to GABA receptor agonists has been reported; however, these studies have employed brainstem slices and therefore the functional identity of the neurons involved has been unclear. Although it seems likely that some changes in central GABAergic systems accompany the recovery of resting activity in the ipsilateral VNC during the development of vestibular compensation, at the present stage

Not a single but multiple populations of GABAergic neurons control sleep.

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Luppi, Pierre-Hervé; Peyron, Christelle; Fort, Patrice

2017-04-01

The role of gamma-amino butyric acid (GABA) in sleep induction and maintenance is well accepted since most insomnia treatments target GABAa receptors. However, the population(s) of GABAergic neurons involved in the beneficial effect of GABA on sleep remains to be identified. This is not an easy task since GABAergic neurons are widely distributed in all brain structures. A recently growing number of populations of GABAergic neurons have been involved in sleep control. We first review here possible candidates for inducing non-rapid eye movement (NREM) sleep including the GABAergic neurons of the ventrolateral preoptic area, the parafacial zone in the brainstem, the nucleus accumbens and the cortex. We also discuss the role of several populations of GABAergic neurons in rapid eye movement (REM) sleep control. Indeed, it is well accepted that muscle atonia occurring during REM sleep is due to a GABA/glycinergic hyperpolarization of motoneurons. Recent evidence strongly suggests that these neurons are located in the ventral medullary reticular formation. It has also recently been shown that neurons containing the neuropeptide melanin concentrating hormone and GABA located in the lateral hypothalamic area control REM sleep expression. Finally, a population of REM-off GABAergic neurons located in the ventrolateral periaqueductal gray has been shown to gate REM sleep by inhibiting glutamatergic neurons located in the sublaterodorsal tegmental nucleus. In summary, recent data clearly indicate that multiple populations of GABAergic neurons located throughout the brain from the cortex to the medulla oblongata control NREM and REM sleep. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigation of synapse formation and function in a glutamatergic-GABAergic two-neuron microcircuit.

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Chang, Chia-Ling; Trimbuch, Thorsten; Chao, Hsiao-Tuan; Jordan, Julia-Christine; Herman, Melissa A; Rosenmund, Christian

2014-01-15

Neural circuits are composed of mainly glutamatergic and GABAergic neurons, which communicate through synaptic connections. Many factors instruct the formation and function of these synapses; however, it is difficult to dissect the contribution of intrinsic cell programs from that of extrinsic environmental effects in an intact network. Here, we perform paired recordings from two-neuron microculture preparations of mouse hippocampal glutamatergic and GABAergic neurons to investigate how synaptic input and output of these two principal cells develop. In our reduced preparation, we found that glutamatergic neurons showed no change in synaptic output or input regardless of partner neuron cell type or neuronal activity level. In contrast, we found that glutamatergic input caused the GABAergic neuron to modify its output by way of an increase in synapse formation and a decrease in synaptic release efficiency. These findings are consistent with aspects of GABAergic synapse maturation observed in many brain regions. In addition, changes in GABAergic output are cell wide and not target-cell specific. We also found that glutamatergic neuronal activity determined the AMPA receptor properties of synapses on the partner GABAergic neuron. All modifications of GABAergic input and output required activity of the glutamatergic neuron. Because our system has reduced extrinsic factors, the changes we saw in the GABAergic neuron due to glutamatergic input may reflect initiation of maturation programs that underlie the formation and function of in vivo neural circuits.

Dysfunctional GABAergic inhibition in the prefrontal cortex leading to "psychotic" hyperactivation

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Tanaka Shoji

2008-04-01

Full Text Available Abstract Background The GABAergic system in the brain seems to be dysfunctional in various psychiatric disorders. Many studies have suggested so far that, in schizophrenia patients, GABAergic inhibition is selectively but consistently reduced in the prefrontal cortex (PFC. Results This study used a computational model of the PFC to investigate the dynamics of the PFC circuit with and without chandelier cells and other GABAergic interneurons. The inhibition by GABAergic interneurons other than chandelier cells effectively regulated the PFC activity with rather low or modest levels of dopaminergic neurotransmission. This activity of the PFC is associated with normal cognitive functions and has an inverted-U shaped profile of dopaminergic modulation. In contrast, the chandelier cell-type inhibition affected only the PFC circuit dynamics in hyperdopaminergic conditions. Reduction of chandelier cell-type inhibition resulted in bistable dynamics of the PFC circuit, in which the upper stable state is associated with a hyperactive mode. When both types of inhibition were reduced, this hyperactive mode and the conventional inverted-U mode merged. Conclusion The results of our simulation suggest that, in schizophrenia, a reduction of GABAergic inhibition increases vulnerability to psychosis by (i producing the hyperactive mode of the PFC with hyperdopaminergic neurotransmission by dysfunctional chandelier cells and (ii increasing the probability of the transition to the hyperactive mode from the conventional inverted-U mode by dysfunctional GABAergic interneurons.

Na+/K+-ATPase inhibition partially mimics the ethanol-induced increase of the Golgi cell-dependent component of the tonic GABAergic current in rat cerebellar granule cells.

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Marvin R Diaz

Full Text Available Cerebellar granule cells (CGNs are one of many neurons that express phasic and tonic GABAergic conductances. Although it is well established that Golgi cells (GoCs mediate phasic GABAergic currents in CGNs, their role in mediating tonic currents in CGNs (CGN-I(tonic is controversial. Earlier studies suggested that GoCs mediate a component of CGN-I(tonic that is present only in preparations from immature rodents. However, more recent studies have detected a GoC-dependent component of CGN-I(tonic in preparations of mature rodents. In addition, acute exposure to ethanol was shown to potentiate the GoC component of CGN-I(tonic and to induce a parallel increase in spontaneous inhibitory postsynaptic current frequency at CGNs. Here, we tested the hypothesis that these effects of ethanol on GABAergic transmission in CGNs are mediated by inhibition of the Na(+/K(+-ATPase. We used whole-cell patch-clamp electrophysiology techniques in cerebellar slices of male rats (postnatal day 23-30. Under these conditions, we reliably detected a GoC-dependent component of CGN-I(tonic that could be blocked with tetrodotoxin. Further analysis revealed a positive correlation between basal sIPSC frequency and the magnitude of the GoC-dependent component of CGN-I(tonic. Inhibition of the Na(+/K(+-ATPase with a submaximal concentration of ouabain partially mimicked the ethanol-induced potentiation of both phasic and tonic GABAergic currents in CGNs. Modeling studies suggest that selective inhibition of the Na(+/K(+-ATPase in GoCs can, in part, explain these effects of ethanol. These findings establish a novel mechanism of action of ethanol on GABAergic transmission in the central nervous system.

Loss of GABAergic inputs in APP/PS1 mouse model of Alzheimer's disease

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Tutu Oyelami

2014-04-01

Full Text Available Alzheimer's disease (AD is characterized by symptoms which include seizures, sleep disruption, loss of memory as well as anxiety in patients. Of particular importance is the possibility of preventing the progressive loss of neuronal projections in the disease. Transgenic mice overexpressing EOFAD mutant PS1 (L166P and mutant APP (APP KM670/671NL Swedish (APP/PS1 develop a very early and robust Amyloid pathology and display synaptic plasticity impairments and cognitive dysfunction. Here we investigated GABAergic neurotransmission, using multi-electrode array (MEA technology and pharmacological manipulation to quantify the effect of GABA Blockers on field excitatory postsynaptic potentials (fEPSP, and immunostaining of GABAergic neurons. Using MEA technology we confirm impaired LTP induction by high frequency stimulation in APPPS1 hippocampal CA1 region that was associated with reduced alteration of the pair pulse ratio after LTP induction. Synaptic dysfunction was also observed under manipulation of external Calcium concentration and input-output curve. Electrophysiological recordings from brain slice of CA1 hippocampus area, in the presence of GABAergic receptors blockers cocktails further demonstrated significant reduction in the GABAergic inputs in APP/PS1 mice. Moreover, immunostaining of GAD65 a specific marker for GABAergic neurons revealed reduction of the GABAergic inputs in CA1 area of the hippocampus. These results might be linked to increased seizure sensitivity, premature death and cognitive dysfunction in this animal model of AD. Further in depth analysis of GABAergic dysfunction in APP/PS1 mice is required and may open new perspectives for AD therapy by restoring GABAergic function.

Neuron-astrocyte interaction enhance GABAergic synaptic transmission in a manner dependent on key metabolic enzymes.

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Przemysław eKaczor; Dariusz eRakus; Jerzy Władysław Mozrzymas; Jerzy Władysław Mozrzymas

2015-01-01

GABA is the major inhibitory neurotransmitter in the adult brain and mechanisms of GABAergic inhibition have been intensely investigated in the past decades. Recent studies provided evidence for an important role of astrocytes in shaping GABAergic currents. One of the most obvious, but yet poorly understood, mechanisms of the cross-talk between GABAergic currents and astrocytes is metabolism including neurotransmitter homeostasis. In particular, how modulation of GABAergic currents by astrocy...

Shared rhythmic subcortical GABAergic input to the entorhinal cortex and presubiculum.

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Viney, Tim James; Salib, Minas; Joshi, Abhilasha; Unal, Gunes; Berry, Naomi; Somogyi, Peter

2018-04-05

Rhythmic theta frequency (~5-12 Hz) oscillations coordinate neuronal synchrony and higher frequency oscillations across the cortex. Spatial navigation and context-dependent episodic memories are represented in several interconnected regions including the hippocampal and entorhinal cortices, but the cellular mechanisms for their dynamic coupling remain to be defined. Using monosynaptically-restricted retrograde viral tracing in mice, we identified a subcortical GABAergic input from the medial septum that terminated in the entorhinal cortex, with collaterals innervating the dorsal presubiculum. Extracellularly recording and labeling GABAergic entorhinal-projecting neurons in awake behaving mice show that these subcortical neurons, named orchid cells, fire in long rhythmic bursts during immobility and locomotion. Orchid cells discharge near the peak of hippocampal and entorhinal theta oscillations, couple to entorhinal gamma oscillations, and target subpopulations of extra-hippocampal GABAergic interneurons. Thus, orchid cells are a specialized source of rhythmic subcortical GABAergic modulation of 'upstream' and 'downstream' cortico-cortical circuits involved in mnemonic functions. © 2018, Viney et al.

Proteinuria and lipoprotein lipase activity in Miniature Schnauzer dogs with and without hypertriglyceridemia.

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Furrow, E; Jaeger, J Q; Parker, V J; Hinchcliff, K W; Johnson, S E; Murdoch, S J; de Boer, I H; Sherding, R G; Brunzell, J D

2016-06-01

Spontaneous hyperlipidemia in rats causes glomerular disease. Idiopathic hypertriglyceridemia (HTG) is prevalent in Miniature Schnauzers, but its relationship with proteinuria is unknown. Decreased activity of major lipid metabolism enzymes, lipoprotein lipase (LPL) and hepatic lipase (HL), may play a role in the cyclic relationship between hyperlipidemia and proteinuria. These enzymes have also not been previously investigated in Miniature Schnauzers. The aims of this study were to determine the relationship between HTG and proteinuria in Miniature Schnauzers and to measure LPL and HL activities in a subset of dogs. Fifty-seven Miniature Schnauzers were recruited (34 with and 23 without HTG). Fasting serum triglyceride concentrations and urine protein-to-creatinine ratios (UPC) were measured in all dogs, and LPL and HL activities were determined in 17 dogs (8 with and 9 without HTG). There was a strong positive correlation between triglyceride concentration and UPC (r = 0.77-0.83, P Schnauzers and could be due to lipid-induced glomerular injury. Reduced LPL activity may contribute to the severity of HTG, but further assay validation is required. Copyright © 2016 Elsevier Ltd. All rights reserved.

GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy.

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Libor Velíšek

Full Text Available Idiopathic generalized epilepsy (IGE syndromes represent about 30% of all epilepsies. They have strong, but elusive, genetic components and sex-specific seizure expression. Multiple linkage and population association studies have connected the bromodomain-containing gene BRD2 to forms of IGE. In mice, a null mutation at the homologous Brd2 locus results in embryonic lethality while heterozygous Brd2+/- mice are viable and overtly normal. However, using the flurothyl model, we now show, that compared to the Brd2+/+ littermates, Brd2+/- males have a decreased clonic, and females a decreased tonic-clonic, seizure threshold. Additionally, long-term EEG/video recordings captured spontaneous seizures in three out of five recorded Brd2+/- female mice. Anatomical analysis of specific regions of the brain further revealed significant differences in Brd2+/- vs +/+ mice. Specifically, there were decreases in the numbers of GABAergic (parvalbumin- or GAD67-immunopositive neurons along the basal ganglia pathway, i.e., in the neocortex and striatum of Brd2+/- mice, compared to Brd2+/+ mice. There were also fewer GABAergic neurons in the substantia nigra reticulata (SNR, yet there was a minor, possibly compensatory increase in the GABA producing enzyme GAD67 in these SNR cells. Further, GAD67 expression in the superior colliculus and ventral medial thalamic nucleus, the main SNR outputs, was significantly decreased in Brd2+/- mice, further supporting GABA downregulation. Our data show that the non-channel-encoding, developmentally critical Brd2 gene is associated with i sex-specific increases in seizure susceptibility, ii the development of spontaneous seizures, and iii seizure-related anatomical changes in the GABA system, supporting BRD2's involvement in human IGE.

Seizure frequency correlates with loss of dentate gyrus GABAergic neurons in a mouse model of temporal lobe epilepsy

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Buckmaster, Paul S.; Abrams, Emily; Wen, Xiling

2018-01-01

Epilepsy occurs in one of 26 people. Temporal lobe epilepsy is common and can be difficult to treat effectively. It can develop after brain injuries that damage the hippocampus. Multiple pathophysiological mechanisms involving the hippocampal dentate gyrus have been proposed. This study evaluated a mouse model of temporal lobe epilepsy to test which pathological changes in the dentate gyrus correlate with seizure frequency and help prioritize potential mechanisms for further study. FVB mice (n = 127) that had experienced status epilepticus after systemic treatment with pilocarpine 31–61 days earlier were video-monitored for spontaneous, convulsive seizures 9 hr/day every day for 24–36 days. Over 4,060 seizures were observed. Seizure frequency ranged from an average of one every 3.6 days to one every 2.1 hr. Hippocampal sections were processed for Nissl stain, Prox1-immunocytochemistry, GluR2-immunocytochemistry, Timm stain, glial fibrillary acidic protein-immunocytochemistry, glutamic acid decarboxylase in situ hybridization, and parvalbumin-immunocytochemistry. Stereological methods were used to measure hilar ectopic granule cells, mossy cells, mossy fiber sprouting, astrogliosis, and GABAergic interneurons. Seizure frequency was not significantly correlated with the generation of hilar ectopic granule cells, the number of mossy cells, the extent of mossy fiber sprouting, the extent of astrogliosis, or the number of GABAergic interneurons in the molecular layer or hilus. Seizure frequency significantly correlated with the loss of GABAergic interneurons in or adjacent to the granule cell layer, but not with the loss of parvalbumin-positive interneurons. These findings prioritize the loss of granule cell layer interneurons for further testing as a potential cause of temporal lobe epilepsy. PMID:28425097

Seizure frequency correlates with loss of dentate gyrus GABAergic neurons in a mouse model of temporal lobe epilepsy.

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Buckmaster, Paul S; Abrams, Emily; Wen, Xiling

2017-08-01

Epilepsy occurs in one of 26 people. Temporal lobe epilepsy is common and can be difficult to treat effectively. It can develop after brain injuries that damage the hippocampus. Multiple pathophysiological mechanisms involving the hippocampal dentate gyrus have been proposed. This study evaluated a mouse model of temporal lobe epilepsy to test which pathological changes in the dentate gyrus correlate with seizure frequency and help prioritize potential mechanisms for further study. FVB mice (n = 127) that had experienced status epilepticus after systemic treatment with pilocarpine 31-61 days earlier were video-monitored for spontaneous, convulsive seizures 9 hr/day every day for 24-36 days. Over 4,060 seizures were observed. Seizure frequency ranged from an average of one every 3.6 days to one every 2.1 hr. Hippocampal sections were processed for Nissl stain, Prox1-immunocytochemistry, GluR2-immunocytochemistry, Timm stain, glial fibrillary acidic protein-immunocytochemistry, glutamic acid decarboxylase in situ hybridization, and parvalbumin-immunocytochemistry. Stereological methods were used to measure hilar ectopic granule cells, mossy cells, mossy fiber sprouting, astrogliosis, and GABAergic interneurons. Seizure frequency was not significantly correlated with the generation of hilar ectopic granule cells, the number of mossy cells, the extent of mossy fiber sprouting, the extent of astrogliosis, or the number of GABAergic interneurons in the molecular layer or hilus. Seizure frequency significantly correlated with the loss of GABAergic interneurons in or adjacent to the granule cell layer, but not with the loss of parvalbumin-positive interneurons. These findings prioritize the loss of granule cell layer interneurons for further testing as a potential cause of temporal lobe epilepsy. © 2017 Wiley Periodicals, Inc.

Fluoxetine impairs GABAergic signaling in hippocampal slices from neonatal rats

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Enrico eCherubini

2013-05-01

Full Text Available Fluoxetine (Prozac, an antidepressant known to selectively inhibit serotonin reuptake, is widely used to treat mood disorders in women suffering from depression during pregnancy and postpartum period. Several lines of evidence suggest that this drug, which crosses the human placenta and is secreted into milk during lactation, exerts its action not only by interfering with serotoninergic but also with GABAergic transmission. GABA is known to play a crucial role in the construction of neuronal circuits early in postnatal development. The immature hippocampus is characterized by an early type of network activity, the so-called Giant Depolarizing Potentials (GDPs, generated by the synergistic action of glutamate and GABA, both depolarizing and excitatory. Here we tested the hypothesis that fluoxetine may interfere with GABAergic signaling during the first postnatal week, thus producing harmful effects on brain development. At micromolar concentrations fluoxetine severely depressed GDPs frequency (IC50 22 M in a reversible manner and independently of its action on serotonin reuptake. This effect was dependent on a reduced GABAergic (but not glutamatergic drive to principal cells most probably from parvalbumin-positive fast spiking neurons. Cholecystokinin-positive GABAergic interneurons were not involved since the effects of the drug persisted when cannabinoid receptors were occluded with WIN55,212-2, a CB1/CB2 receptor agonist. Fluoxetine effects on GABAergic transmission were associated with a reduced firing rate of both principal cells and interneurons further suggesting that changes in network excitability account for GDPs disruption. This may have critical consequences on the functional organization and stabilization of neuronal circuits early in postnatal development.

GABA regulates the multidirectional tangential migration of GABAergic interneurons in living neonatal mice.

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Hiroyuki Inada

Full Text Available Cortical GABAergic interneurons originate from ganglionic eminences and tangentially migrate into the cortical plate at early developmental stages. To elucidate the characteristics of this migration of GABAergic interneurons in living animals, we established an experimental design specialized for in vivo time-lapse imaging of the neocortex of neonate mice with two-photon laser-scanning microscopy. In vesicular GABA/glycine transporter (VGAT-Venus transgenic mice from birth (P0 through P3, we observed multidirectional tangential migration of genetically-defined GABAergic interneurons in the neocortical marginal zone. The properties of this migration, such as the motility rate (distance/hr, the direction moved, and the proportion of migrating neurons to stationary neurons, did not change through P0 to P3, although the density of GABAergic neurons at the marginal zone decreased with age. Thus, the characteristics of the tangential motility of individual GABAergic neurons remained constant in development. Pharmacological block of GABA(A receptors and of the Na⁺-K⁺-Cl⁻ cotransporters, and chelating intracellular Ca²⁺, all significantly reduced the motility rate in vivo. The motility rate and GABA content within the cortex of neonatal VGAT-Venus transgenic mice were significantly greater than those of GAD67-GFP knock-in mice, suggesting that extracellular GABA concentration could facilitate the multidirectional tangential migration. Indeed, diazepam applied to GAD67-GFP mice increased the motility rate substantially. In an in vitro neocortical slice preparation, we confirmed that GABA induced a NKCC sensitive depolarization of GABAergic interneurons in VGAT-Venus mice at P0-P3. Thus, activation of GABA(AR by ambient GABA depolarizes GABAergic interneurons, leading to an acceleration of their multidirectional motility in vivo.

Functional hallmarks of GABAergic synapse maturation and the diverse roles of neurotrophins

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Rosemarie eGrantyn

2011-07-01

Full Text Available Functional impairment of the adult brain can result from deficits in the ontogeny of GABAergic synaptic transmission. Gene defects underlying autism spectrum disorders, Rett’s syndrome or some forms of epilepsy, but also a diverse set of syndromes accompanying perinatal trauma, hormonal imbalances, intake of sleep-inducing or mood-improving drugs or, quite common, alcohol intake during pregnancy can alter GABA signaling early in life. The search for therapeutically relevant endogenous molecules or exogenous compounds able to alleviate the consequences of dysfunction of GABAergic transmission in the embryonic or postnatal brain requires a clear understanding of its site- and state-dependent development. At the level of single synapses, it is necessary to discriminate between presynaptic and postsynaptic alterations, and to define parameters that can be regarded as both suitable and accessible for the quantification of developmental changes. Here we focus on the performance of GABAergic synapses in two brain structures, the hippocampus and the superior colliculus, describe some novel aspects of neurotrophin effects during the development of GABAergic synaptic transmission and examine the applicability of the following rules: 1 Synaptic transmission starts with GABA, 2 Nascent/immature GABAergic synapses operate in a ballistic mode (multivesicular release, 3 Immature synaptic terminals release vesicles with higher probability than mature synapses, 4 Immature GABAergic synapses are prone to paired pulse and tetanic depression, 5 Synapse maturation is characterized by an increasing dominance of synchronous over asynchronous release, 6 In immature neurons GABA acts as a depolarizing transmitter, 7 Synapse maturation implies IPSC shortening due to an increase in alpha1 subunit expression, 8 Extrasynaptic (tonic conductances can inhibit the development of synaptic (phasic GABA actions.

Caffeine-Induced Suppression of GABAergic Inhibition and Calcium-Independent Metaplasticity

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Masako Isokawa

2016-01-01

Full Text Available GABAergic inhibition plays a critical role in the regulation of neuron excitability; thus, it is subject to modulations by many factors. Recent evidence suggests the elevation of intracellular calcium ([Ca2+]i and calcium-dependent signaling molecules underlie the modulations. Caffeine induces a release of calcium from intracellular stores. We tested whether caffeine modulated GABAergic transmission by increasing [Ca2+]i. A brief local puff-application of caffeine to hippocampal CA1 pyramidal cells transiently suppressed GABAergic inhibitory postsynaptic currents (IPSCs by 73.2 ± 6.98%. Time course of suppression and the subsequent recovery of IPSCs resembled DSI (depolarization-induced suppression of inhibition, mediated by endogenous cannabinoids that require a [Ca2+]i rise. However, unlike DSI, caffeine-induced suppression of IPSCs (CSI persisted in the absence of a [Ca2+]i rise. Intracellular applications of BAPTA and ryanodine (which blocks caffeine-induced calcium release from intracellular stores failed to prevent the generation of CSI. Surprisingly, ruthenium red, an inhibitor of multiple calcium permeable/release channels including those of stores, induced metaplasticity by amplifying the magnitude of CSI independently of calcium. This metaplasticity was accompanied with the generation of a large inward current. Although ionic basis of this inward current is undetermined, the present result demonstrates that caffeine has a robust Ca2+-independent inhibitory action on GABAergic inhibition and causes metaplasticity by opening plasma membrane channels.

The space where aging acts: focus on the GABAergic synapse.

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Rozycka, Aleksandra; Liguz-Lecznar, Monika

2017-08-01

As it was established that aging is not associated with massive neuronal loss, as was believed in the mid-20th Century, scientific interest has addressed the influence of aging on particular neuronal subpopulations and their synaptic contacts, which constitute the substrate for neural plasticity. Inhibitory neurons represent the most complex and diverse group of neurons, showing distinct molecular and physiological characteristics and possessing a compelling ability to control the physiology of neural circuits. This review focuses on the aging of GABAergic neurons and synapses. Understanding how aging affects synapses of particular neuronal subpopulations may help explain the heterogeneity of aging-related effects. We reviewed the literature concerning the effects of aging on the numbers of GABAergic neurons and synapses as well as aging-related alterations in their presynaptic and postsynaptic components. Finally, we discussed the influence of those changes on the plasticity of the GABAergic system, highlighting our results concerning aging in mouse somatosensory cortex and linking them to plasticity impairments and brain disorders. We posit that aging-induced impairments of the GABAergic system lead to an inhibitory/excitatory imbalance, thereby decreasing neuron's ability to respond with plastic changes to environmental and cellular challenges, leaving the brain more vulnerable to cognitive decline and damage by synaptopathic diseases. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Developmental changes in GABAergic neurotransmission to presympathetic and cardiac parasympathetic neurons in the brainstem.

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Dergacheva, Olga; Boychuk, Carie R; Mendelowitz, David

2013-08-01

Cardiovascular function is regulated by a dynamic balance composed of sympathetic and parasympathetic activity. Sympathoexcitatory presympathetic neurons (PSNs) in the rostral ventrolateral medulla project directly to cardiac and vasomotor sympathetic preganglionic neurons in the spinal cord. In proximity to the PSNs in the medulla, there are preganglionic cardiac vagal neurons (CVNs) within the nucleus ambiguus, which are critical for parasympathetic control of heart rate. Both CVNs and PSNs receive GABAergic synaptic inputs that change with challenges such as hypoxia and hypercapnia (H/H). Autonomic control of cardiovascular function undergoes significant changes during early postnatal development; however, little is known regarding postnatal maturation of GABAergic neurotransmission to these neurons. In this study, we compared changes in GABAergic inhibitory postsynaptic currents (IPSCs) in CVNs and PSNs under control conditions and during H/H in postnatal day 2-5 (P5), 16-20 (P20), and 27-30 (P30) rats using an in vitro brainstem slice preparation. There was a significant enhancement in GABAergic neurotransmission to both CVNs and PSNs at age P20 compared with P5 and P30, with a more pronounced increase in PSNs. H/H did not significantly alter this enhanced GABAergic neurotransmission to PSNs in P20 animals. However, the frequency of GABAergic IPSCs in PSNs was reduced by H/H in P5 and P30 animals. In CVNs, H/H elicited an inhibition of GABAergic neurotransmission in all ages studied, with the most pronounced inhibition occurring at P20. In conclusion, there are critical development periods at which significant rearrangement occurs in the central regulation of cardiovascular function.

Role of astrocytic transport processes in glutamatergic and GABAergic neurotransmission

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Schousboe, A; Sarup, A; Bak, L K

2004-01-01

The fine tuning of both glutamatergic and GABAergic neurotransmission is to a large extent dependent upon optimal function of astrocytic transport processes. Thus, glutamate transport in astrocytes is mandatory to maintain extrasynaptic glutamate levels sufficiently low to prevent excitotoxic...... neuronal damage. In GABA synapses hyperactivity of astroglial GABA uptake may lead to diminished GABAergic inhibitory activity resulting in seizures. As a consequence of this the expression and functional activity of astrocytic glutamate and GABA transport is regulated in a number of ways...

Distinct behavioral consequences of short-term and prolonged GABAergic depletion in prefrontal cortex and dorsal hippocampus

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Judith M. Reichel

2015-01-01

Full Text Available GABAergic interneurons are essential for a functional equilibrium between excitatory and inhibitory impulses throughout the CNS. Disruption of this equilibrium can lead to various neurological or neuropsychiatric disorders such as epileptic seizures or schizophrenia. Schizophrenia itself is clinically defined by negative- (e.g. depression and positive- (e.g. hallucinations symptoms as well as cognitive dysfunction. GABAergic interneurons are proposed to play a central role in the etiology and progression of schizophrenia; however, the specific mechanisms and the time-line of symptom development as well as the distinct involvement of cortical and hippocampal GABAergic interneurons in the etiology of schizophrenia-related symptoms are still not conclusively resolved.Previous work demonstrated that GABAergic interneurons can be selectively depleted in adult mice by means of saporin-conjugated anti-vesicular GABA transporter antibodies (SAVAs in vitro and in vivo. Given their involvement in Schizophrenia-related disease etiology, we ablated GABAergic interneurons in the medial prefrontal cortex (mPFC and dorsal hippocampus (dHPC in adult male C57BL/6N mice. Subsequently we assessed alterations in anxiety, sensory processing, hyperactivity and cognition after long-term (>14 days and short-term (< 14 days GABAergic depletion. Long-term GABAergic depletion in the mPFC resulted in a decrease in sensorimotor-gating and impairments in cognitive flexibility. Notably, the same treatment at the level of the dHPC completely abolished spatial learning capabilities. Short-term GABAergic depletion in the dHPC revealed a transient hyperactive phenotype as well as marked impairments regarding the acquisition of a spatial memory. In contrast, recall of a spatial memory was not affected by the same intervention. These findings emphasize the importance of functional local GABAergic networks for the encoding but not the recall of hippocampus-dependent spatial memories.

In vivo temporal property of GABAergic neural transmission in collateral feed-forward inhibition system of hippocampal-prefrontal pathway.

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Takita, Masatoshi; Kuramochi, Masahito; Izaki, Yoshinori; Ohtomi, Michiko

2007-05-30

Anatomical evidence suggests that rat CA1 hippocampal afferents collaterally innervate excitatory projecting pyramidal neurons and inhibitory interneurons, creating a disynaptic, feed-forward inhibition microcircuit in the medial prefrontal cortex (mPFC). We investigated the temporal relationship between the frequency of paired synaptic transmission and gamma-aminobutyric acid (GABA)ergic receptor-mediated modulation of the microcircuit in vivo under urethane anesthesia. Local perfusions of a GABAa antagonist (-)-bicuculline into the mPFC via microdialysis resulted in a statistically significant disinhibitory effect on intrinsic GABA action, increasing the first and second mPFC responses following hippocampal paired stimulation at interstimulus intervals of 100-200 ms, but not those at 25-50 ms. This (-)-bicuculline-induced disinhibition was compensated by the GABAa agonist muscimol, which itself did not attenuate the intrinsic oscillation of the local field potentials. The perfusion of a sub-minimal concentration of GABAb agonist (R)-baclofen slightly enhanced the synaptic transmission, regardless of the interstimulus interval. In addition to the tonic control by spontaneous fast-spiking GABAergic neurons, it is clear the sequential transmission of the hippocampal-mPFC pathway can phasically drive the collateral feed-forward inhibition system through activation of a GABAa receptor, bringing an active signal filter to the various types of impulse trains that enter the mPFC from the hippocampus in vivo.

Key Metabolic Enzymes Underlying Astrocytic Upregulation of GABAergic Plasticity

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Przemysław T. Kaczor

2017-05-01

Full Text Available GABAergic plasticity is recognized as a key mechanism of shaping the activity of the neuronal networks. However, its description is challenging because of numerous neuron-specific mechanisms. In particular, while essential role of glial cells in the excitatory plasticity is well established, their involvement in GABAergic plasticity only starts to emerge. To address this problem, we used two models: neuronal cell culture (NC and astrocyte-neuronal co-culture (ANCC, where we chemically induced long-term potentiation at inhibitory synapses (iLTP. iLTP could be induced both in NC and ANCC but in ANCC its extent was larger. Importantly, this functional iLTP manifestation was accompanied by an increase in gephyrin puncta size. Furthermore, blocking astrocyte Krebs cycle with fluoroacetate (FA in ANCC prevented enhancement of both mIPSC amplitude and gephyrin puncta size but this effect was not observed in NC, indicating a key role in neuron-astrocyte cross-talk. Blockade of monocarboxylate transport with α-Cyano-4-hydroxycinnamic acid (4CIN abolished iLTP both in NC and ANCC and in the latter model prevented also enlargement of gephyrin puncta. Similarly, blockade of glycogen phosphorylase with BAYU6751 prevented enlargement of gephyrin puncta upon iLTP induction. Finally, block of glutamine synthetase with methionine sulfoxide (MSO nearly abolished mIPSC increase in both NMDA stimulated cell groups but did not prevent enlargement of gephyrin puncta. In conclusion, we provide further evidence that GABAergic plasticity is strongly regulated by astrocytes and the underlying mechanisms involve key metabolic enzymes. Considering the strategic role of GABAergic interneurons, the plasticity described here indicates possible mechanism whereby metabolism regulates the network activity.

Shaping inhibition: activity dependent structural plasticity of GABAergic synapses

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Carmen E Flores

2014-10-01

Full Text Available Inhibitory transmission through the neurotransmitter Ɣ-aminobutyric acid (GABA shapes network activity in the mammalian cerebral cortex by filtering synaptic incoming information and dictating the activity of principal cells. The incredibly diverse population of cortical neurons that use GABA as neurotransmitter shows an equally diverse range of mechanisms that regulate changes in the strength of GABAergic synaptic transmission and allow them to dynamically follow and command the activity of neuronal ensembles. Similarly to glutamatergic synaptic transmission, activity-dependent functional changes in inhibitory neurotransmission are accompanied by alterations in GABAergic synapse structure that range from morphological reorganization of postsynaptic density to de novo formation and elimination of inhibitory contacts. Here we review several aspects of structural plasticity of inhibitory synapses, including its induction by different forms of neuronal activity, behavioral and sensory experience and the molecular mechanisms and signaling pathways involved. We discuss the functional consequences of GABAergic synapse structural plasticity for information processing and memory formation in view of the heterogenous nature of the structural plasticity phenomena affecting inhibitory synapses impinging on somatic and dendritic compartments of cortical and hippocampal neurons.

Serotonin increases synaptic activity in olfactory bulb glomeruli.

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Brill, Julia; Shao, Zuoyi; Puche, Adam C; Wachowiak, Matt; Shipley, Michael T

2016-03-01

Serotoninergic fibers densely innervate olfactory bulb glomeruli, the first sites of synaptic integration in the olfactory system. Acting through 5HT2A receptors, serotonin (5HT) directly excites external tufted cells (ETCs), key excitatory glomerular neurons, and depolarizes some mitral cells (MCs), the olfactory bulb's main output neurons. We further investigated 5HT action on MCs and determined its effects on the two major classes of glomerular interneurons: GABAergic/dopaminergic short axon cells (SACs) and GABAergic periglomerular cells (PGCs). In SACs, 5HT evoked a depolarizing current mediated by 5HT2C receptors but did not significantly impact spike rate. 5HT had no measurable direct effect in PGCs. Serotonin increased spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) in PGCs and SACs. Increased sEPSCs were mediated by 5HT2A receptors, suggesting that they are primarily due to enhanced excitatory drive from ETCs. Increased sIPSCs resulted from elevated excitatory drive onto GABAergic interneurons and augmented GABA release from SACs. Serotonin-mediated GABA release from SACs was action potential independent and significantly increased miniature IPSC frequency in glomerular neurons. When focally applied to a glomerulus, 5HT increased MC spontaneous firing greater than twofold but did not increase olfactory nerve-evoked responses. Taken together, 5HT modulates glomerular network activity in several ways: 1) it increases ETC-mediated feed-forward excitation onto MCs, SACs, and PGCs; 2) it increases inhibition of glomerular interneurons; 3) it directly triggers action potential-independent GABA release from SACs; and 4) these network actions increase spontaneous MC firing without enhancing responses to suprathreshold sensory input. This may enhance MC sensitivity while maintaining dynamic range. Copyright © 2016 the American Physiological Society.

Differentiation and functional incorporation of embryonic stem cell-derived GABAergic interneurons in the dentate gyrus of mice with temporal lobe epilepsy.

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Maisano, Xu; Litvina, Elizabeth; Tagliatela, Stephanie; Aaron, Gloster B; Grabel, Laura B; Naegele, Janice R

2012-01-04

Cell therapies for neurological disorders require an extensive knowledge of disease-associated neuropathology and procedures for generating neurons for transplantation. In many patients with severe acquired temporal lobe epilepsy (TLE), the dentate gyrus exhibits sclerosis and GABAergic interneuron degeneration. Mounting evidence suggests that therapeutic benefits can be obtained by transplanting fetal GABAergic progenitors into the dentate gyrus in rodents with TLE, but the scarcity of human fetal cells limits applicability in patient populations. In contrast, virtually limitless quantities of neural progenitors can be obtained from embryonic stem (ES) cells. ES cell-based therapies for neurological repair in TLE require evidence that the transplanted neurons integrate functionally and replace cell types that degenerate. To address these issues, we transplanted mouse ES cell-derived neural progenitors (ESNPs) with ventral forebrain identities into the hilus of the dentate gyrus of mice with TLE and evaluated graft differentiation, mossy fiber sprouting, cellular morphology, and electrophysiological properties of the transplanted neurons. In addition, we compared electrophysiological properties of the transplanted neurons with endogenous hilar interneurons in mice without TLE. The majority of transplanted ESNPs differentiated into GABAergic interneuron subtypes expressing calcium-binding proteins parvalbumin, calbindin, or calretinin. Global suppression of mossy fiber sprouting was not observed; however, ESNP-derived neurons formed dense axonal arborizations in the inner molecular layer and throughout the hilus. Whole-cell hippocampal slice electrophysiological recordings and morphological analyses of the transplanted neurons identified five basic types; most with strong after-hyperpolarizations and smooth or sparsely spiny dendritic morphologies resembling endogenous hippocampal interneurons. Moreover, intracellular recordings of spontaneous EPSCs indicated that

Regulation of the Hippocampal Network by VGLUT3-Positive CCK- GABAergic Basket Cells

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Caroline Fasano

2017-05-01

Full Text Available Hippocampal interneurons release the inhibitory transmitter GABA to regulate excitation, rhythm generation and synaptic plasticity. A subpopulation of GABAergic basket cells co-expresses the GABA/glycine vesicular transporters (VIAAT and the atypical type III vesicular glutamate transporter (VGLUT3; therefore, these cells have the ability to signal with both GABA and glutamate. GABAergic transmission by basket cells has been extensively characterized but nothing is known about the functional implications of VGLUT3-dependent glutamate released by these cells. Here, using VGLUT3-null mice we observed that the loss of VGLUT3 results in a metaplastic shift in synaptic plasticity at Shaeffer’s collaterals – CA1 synapses and an altered theta oscillation. These changes were paralleled by the loss of a VGLUT3-dependent inhibition of GABAergic current in CA1 pyramidal layer. Therefore presynaptic type III metabotropic could be activated by glutamate released from VGLUT3-positive interneurons. This putative presynaptic heterologous feedback mechanism inhibits local GABAergic tone and regulates the hippocampal neuronal network.

Feedforward and feedback inhibition in neostriatal GABAergic spiny neurons.

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Tepper, James M; Wilson, Charles J; Koós, Tibor

2008-08-01

There are two distinct inhibitory GABAergic circuits in the neostriatum. The feedforward circuit consists of a relatively small population of GABAergic interneurons that receives excitatory input from the neocortex and exerts monosynaptic inhibition onto striatal spiny projection neurons. The feedback circuit comprises the numerous spiny projection neurons and their interconnections via local axon collaterals. This network has long been assumed to provide the majority of striatal GABAergic inhibition and to sharpen and shape striatal output through lateral inhibition, producing increased activity in the most strongly excited spiny cells at the expense of their less strongly excited neighbors. Recent results, mostly from recording experiments of synaptically connected pairs of neurons, have revealed that the two GABAergic circuits differ markedly in terms of the total number of synapses made by each, the strength of the postsynaptic response detected at the soma, the extent of presynaptic convergence and divergence and the net effect of the activation of each circuit on the postsynaptic activity of the spiny neuron. These data have revealed that the feedforward inhibition is powerful and widespread, with spiking in a single interneuron being capable of significantly delaying or even blocking the generation of spikes in a large number of postsynaptic spiny neurons. In contrast, the postsynaptic effects of spiking in a single presynaptic spiny neuron on postsynaptic spiny neurons are weak when measured at the soma, and unable to significantly affect spike timing or generation. Further, reciprocity of synaptic connections between spiny neurons is only rarely observed. These results suggest that the bulk of the fast inhibition that has the strongest effects on spiny neuron spike timing comes from the feedforward interneuronal system whereas the axon collateral feedback system acts principally at the dendrites to control local excitability as well as the overall level of

Cryopreservation of GABAergic Neuronal Precursors for Cell-Based Therapy.

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Daniel Rodríguez-Martínez

Full Text Available Cryopreservation protocols are essential for stem cells storage in order to apply them in the clinic. Here we describe a new standardized cryopreservation protocol for GABAergic neural precursors derived from the medial glanglionic eminence (MGE, a promising source of GABAergic neuronal progenitors for cell therapy against interneuron-related pathologies. We used 10% Me2SO as cryoprotectant and assessed the effects of cell culture amplification and cellular organization, as in toto explants, neurospheres, or individualized cells, on post-thaw cell viability and retrieval. We confirmed that in toto cryopreservation of MGE explants is an optimal preservation system to keep intact the interneuron precursor properties for cell transplantation, together with a high cell viability (>80% and yield (>70%. Post-thaw proliferation and self-renewal of the cryopreserved precursors were tested in vitro. In addition, their migration capacity, acquisition of mature neuronal morphology, and potency to differentiate into multiple interneuron subtypes were also confirmed in vivo after transplantation. The results show that the cryopreserved precursor features remained intact and were similar to those immediately transplanted after their dissection from the MGE. We hope this protocol will facilitate the generation of biobanks to obtain a permanent and reliable source of GABAergic precursors for clinical application in cell-based therapies against interneuronopathies.

Developmental changes in GABAergic mechanisms in human visual cortex across the lifespan

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Joshua G A Pinto

2010-06-01

Full Text Available Functional maturation of visual cortex is linked with dynamic changes in synaptic expression of GABAergic mechanisms. These include setting the excitation-inhibition balance required for experience-dependent plasticity, as well as, intracortical inhibition underlying development and aging of receptive field properties. Animal studies have shown developmental regulation of GABAergic mechanisms in visual cortex. In this study, we show for the first time how these mechanisms develop in the human visual cortex across the lifespan. We used Western blot analysis of postmortem tissue from human primary visual cortex (n=30, range: 20 days to 80 years to quantify expression of 8 pre- and post-synaptic GABAergic markers. We quantified the inhibitory modulating cannabinoid receptor (CB1, GABA vesicular transporter (VGAT, GABA synthesizing enzymes (GAD65/GAD67, GABAA receptor anchoring protein (Gephyrin, and GABAA receptor subunits (GABAA∝1, GABAA∝2, GABAA∝3. We found a complex pattern of changes, many of which were prolonged and continued well into into the teen, young adult, and even older adult years. These included a monotonic increase or decrease (GABAA∝1, GABAA∝2, a biphasic increase then decrease (GAD65, Gephyrin, or multiple increases and decreases (VGAT, CB1 across the lifespan. Comparing the balances between the pre- and post-synaptic markers we found 3 main transitions (early childhood, early teen years, aging when there were rapid switches in the composition of the GABAergic signaling system, indicating that functioning of the GABAergic system must change as the visual cortex develops and ages. Furthermore, these results provide key information for translating therapies developed in animal models into effective treatments for amblyopia in humans.

The Memory-Impairing Effects of Septal GABA Receptor Activation Involve GABAergic Septo-Hippocampal Projection Neurons

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Krebs-Kraft, Desiree L.; Wheeler, Marina G.; Parent, Marise B.

2007-01-01

Septal infusions of the [gamma]-aminobutyric acid (GABA)[subscript A] agonist muscimol impair memory, and the effect likely involves the hippocampus. GABA[subscript A] receptors are present on the perikarya of cholinergic and GABAergic septo-hippocampal (SH) projections. The current experiments determined whether GABAergic SH projections are…

Deficient GABAergic gliotransmission may cause broader sensory tuning in schizophrenia.

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Hoshino, Osamu

2013-12-01

We examined how the depression of intracortical inhibition due to a reduction in ambient GABA concentration impairs perceptual information processing in schizophrenia. A neural network model with a gliotransmission-mediated ambient GABA regulatory mechanism was simulated. In the network, interneuron-to-glial-cell and principal-cell-to-glial-cell synaptic contacts were made. The former hyperpolarized glial cells and let their transporters import (remove) GABA from the extracellular space, thereby lowering ambient GABA concentration, reducing extrasynaptic GABAa receptor-mediated tonic inhibitory current, and thus exciting principal cells. In contrast, the latter depolarized the glial cells and let the transporters export GABA into the extracellular space, thereby elevating the ambient GABA concentration and thus inhibiting the principal cells. A reduction in ambient GABA concentration was assumed for a schizophrenia network. Multiple dynamic cell assemblies were organized as sensory feature columns. Each cell assembly responded to one specific feature stimulus. The tuning performance of the network to an applied feature stimulus was evaluated in relation to the level of ambient GABA. Transporter-deficient glial cells caused a deficit in GABAergic gliotransmission and reduced ambient GABA concentration, which markedly deteriorated the tuning performance of the network, broadening the sensory tuning. Interestingly, the GABAergic gliotransmission mechanism could regulate local ambient GABA levels: it augmented ambient GABA around stimulus-irrelevant principal cells, while reducing ambient GABA around stimulus-relevant principal cells, thereby ensuring their selective responsiveness to the applied stimulus. We suggest that a deficit in GABAergic gliotransmission may cause a reduction in ambient GABA concentration, leading to a broadening of sensory tuning in schizophrenia. The GABAergic gliotransmission mechanism proposed here may have an important role in the

Impaired GABAergic Inhibition in the Prefrontal Cortex of Early Postnatal Phencyclidine (PCP)-Treated Rats

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Kjaerby, Celia; Broberg, Brian V; Kristiansen, Uffe

2014-01-01

A compromised ¿-aminobutyric acid (GABA)ergic system is hypothesized to be part of the underlying pathophysiology of schizophrenia. N-methyl-d-aspartate (NMDA) receptor hypofunction during neurodevelopment is proposed to disrupt maturation of interneurons causing an impaired GABAergic transmissio...... postnatal PCP-treated rats and support the hypothesis that PCP administration during neurodevelopment affects the functionality of interneurons in later life....

GABAergic interneuron to astrocyte signalling: a neglected form of cell communication in the brain.

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Losi, Gabriele; Mariotti, Letizia; Carmignoto, Giorgio

2014-10-19

GABAergic interneurons represent a minority of all cortical neurons and yet they efficiently control neural network activities in all brain areas. In parallel, glial cell astrocytes exert a broad control of brain tissue homeostasis and metabolism, modulate synaptic transmission and contribute to brain information processing in a dynamic interaction with neurons that is finely regulated in time and space. As most studies have focused on glutamatergic neurons and excitatory transmission, our knowledge of functional interactions between GABAergic interneurons and astrocytes is largely defective. Here, we critically discuss the currently available literature that hints at a potential relevance of this specific signalling in brain function. Astrocytes can respond to GABA through different mechanisms that include GABA receptors and transporters. GABA-activated astrocytes can, in turn, modulate local neuronal activity by releasing gliotransmitters including glutamate and ATP. In addition, astrocyte activation by different signals can modulate GABAergic neurotransmission. Full clarification of the reciprocal signalling between different GABAergic interneurons and astrocytes will improve our understanding of brain network complexity and has the potential to unveil novel therapeutic strategies for brain disorders. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Interplay between glutamatergic and GABAergic neurotransmission alterations in cognitive and motor impairment in minimal hepatic encephalopathy.

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Llansola, Marta; Montoliu, Carmina; Agusti, Ana; Hernandez-Rabaza, Vicente; Cabrera-Pastor, Andrea; Gomez-Gimenez, Belen; Malaguarnera, Michele; Dadsetan, Sherry; Belghiti, Majedeline; Garcia-Garcia, Raquel; Balzano, Tiziano; Taoro, Lucas; Felipo, Vicente

2015-09-01

The cognitive and motor alterations in hepatic encephalopathy (HE) are the final result of altered neurotransmission and communication between neurons in neuronal networks and circuits. Different neurotransmitter systems cooperate to modulate cognitive and motor function, with a main role for glutamatergic and GABAergic neurotransmission in different brain areas and neuronal circuits. There is an interplay between glutamatergic and GABAergic neurotransmission alterations in cognitive and motor impairment in HE. This interplay may occur: (a) in different brain areas involved in specific neuronal circuits; (b) in the same brain area through cross-modulation of glutamatergic and GABAergic neurotransmission. We will summarize some examples of the (1) interplay between glutamatergic and GABAergic neurotransmission alterations in different areas in the basal ganglia-thalamus-cortex circuit in the motor alterations in minimal hepatic encephalopathy (MHE); (2) interplay between glutamatergic and GABAergic neurotransmission alterations in cerebellum in the impairment of cognitive function in MHE through altered function of the glutamate-nitric oxide-cGMP pathway. We will also comment the therapeutic implications of the above studies and the utility of modulators of glutamate and GABA receptors to restore cognitive and motor function in rats with hyperammonemia and hepatic encephalopathy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Organization of GABAergic synaptic circuits in the rat ventral tegmental area.

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Ciccarelli, Alessandro; Calza, Arianna; Panzanelli, Patrizia; Concas, Alessandra; Giustetto, Maurizio; Sassoè-Pognetto, Marco

2012-01-01

The ventral tegmental area (VTA) is widely implicated in drug addiction and other psychiatric disorders. This brain region is densely populated by dopaminergic (DA) neurons and also contains a sparse population of γ-aminobutyric acid (GABA)ergic cells that regulate the activity of the principal neurons. Therefore, an in-depth knowledge of the organization of VTA GABAergic circuits and of the plasticity induced by drug consumption is essential for understanding the mechanisms by which drugs induce stable changes in brain reward circuits. Using immunohistochemistry, we provide a detailed description of the localization of major GABA(A) and GABA(B) receptor subunits in the rat VTA. We show that DA and GABAergic cells express both GABA(A) and GABA(B) receptors. However VTA neurons differ considerably in the expression of GABA(A) receptor subunits, as the α1 subunit is associated predominantly with non-DA cells, whereas the α3 subunit is present at low levels in both types of VTA neurons. Using an unbiased stereological method, we then demonstrate that α1-positive elements represent only a fraction of non-DA neurons and that the ratio of DA and non-DA cells is quite variable throughout the rostro-caudal extent of the VTA. Interestingly, DA and non-DA cells receive a similar density of perisomatic synapses, whereas axo-dendritic synapses are significantly more abundant in non-DA cells, indicating that local interneurons receive prominent GABAergic inhibition. These findings reveal a differential expression of GABA receptor subtypes in the two major categories of VTA neurons and provide an anatomical basis for interpreting the plasticity of inhibitory circuits induced by drug exposure.

Organization of GABAergic synaptic circuits in the rat ventral tegmental area.

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Alessandro Ciccarelli

Full Text Available The ventral tegmental area (VTA is widely implicated in drug addiction and other psychiatric disorders. This brain region is densely populated by dopaminergic (DA neurons and also contains a sparse population of γ-aminobutyric acid (GABAergic cells that regulate the activity of the principal neurons. Therefore, an in-depth knowledge of the organization of VTA GABAergic circuits and of the plasticity induced by drug consumption is essential for understanding the mechanisms by which drugs induce stable changes in brain reward circuits. Using immunohistochemistry, we provide a detailed description of the localization of major GABA(A and GABA(B receptor subunits in the rat VTA. We show that DA and GABAergic cells express both GABA(A and GABA(B receptors. However VTA neurons differ considerably in the expression of GABA(A receptor subunits, as the α1 subunit is associated predominantly with non-DA cells, whereas the α3 subunit is present at low levels in both types of VTA neurons. Using an unbiased stereological method, we then demonstrate that α1-positive elements represent only a fraction of non-DA neurons and that the ratio of DA and non-DA cells is quite variable throughout the rostro-caudal extent of the VTA. Interestingly, DA and non-DA cells receive a similar density of perisomatic synapses, whereas axo-dendritic synapses are significantly more abundant in non-DA cells, indicating that local interneurons receive prominent GABAergic inhibition. These findings reveal a differential expression of GABA receptor subtypes in the two major categories of VTA neurons and provide an anatomical basis for interpreting the plasticity of inhibitory circuits induced by drug exposure.

5-Hydroxytryptamine 1A/7 and 4alpha receptors differentially prevent opioid-induced inhibition of brain stem cardiorespiratory function.

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Wang, Xin; Dergacheva, Olga; Kamendi, Harriet; Gorini, Christopher; Mendelowitz, David

2007-08-01

Opioids evoke respiratory depression, bradycardia, and reduced respiratory sinus arrhythmia, whereas serotonin (5-HT) agonists stimulate respiration and cardiorespiratory interactions. This study tested whether serotonin agonists can prevent the inhibitory effects of opioids on cardiorespiratory function. Spontaneous and rhythmic inspiratory-related activity and gamma-aminobutyric acid (GABA) neurotransmission to premotor parasympathetic cardioinhibitory neurons in the nucleus ambiguus were recorded simultaneously in an in vitro thick slice preparation. The mu-opioid agonist fentanyl inhibited respiratory frequency. The 5-hydroxytryptamine 1A/7 receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin increased respiratory frequency by itself and also prevented the fentanyl-induced respiratory depression. The 5-hydroxytryptamine 4alpha agonist BIMU-8 did not by itself change inspiratory activity but prevented the mu-opioid-mediated respiratory depression. Both spontaneous and inspiratory-evoked GABAergic neurotransmission to cardiac vagal neurons were inhibited by fentanyl. 8-Hydroxy-2-(di-n-propylamino)tetralin inhibited spontaneous but not inspiratory-evoked GABAergic activity to parasympathetic cardiac neurons. However, 8-hydroxy-2-(di-n-propylamino)tetralin differentially altered the opioid-mediated depression of inspiratory-evoked GABAergic activity but did not change the opioid-induced reduction in spontaneous GABAergic neurotransmission. In contrast, BIMU-8 did not alter GABAergic neurotransmission to cardiac vagal neurons by itself but prevented the fentanyl depression of both spontaneous and inspiratory-elicited GABAergic neurotransmission to cardiac vagal neurons. In the presence of tetrodotoxin, the inhibition of GABAergic inhibitory postsynaptic currents with fentanyl is prevented by coapplication of BIMU-8, indicating that BIMU-8 acts at presynaptic GABAergic terminals to prevent fentanyl-induced depression. These results suggest that activation of 5

Demyelinating polyneuropathy with focally folded myelin sheaths in a family of Miniature Schnauzer dogs.

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Vanhaesebrouck, An E; Couturier, Jérôme; Cauzinille, Laurent; Mizisin, Andrew P; Shelton, G Diane; Granger, Nicolas

2008-12-15

A spontaneous demyelinating polyneuropathy in two young Miniature Schnauzer dogs was characterized clinically, electrophysiologically and histopathologically. Both dogs were related and a third dog, belonging to the same family, had similar clinical signs. On presentation, clinical signs were restricted to respiratory dysfunction. Electrophysiological tests showed a dramatic decrease in both motor and sensory nerve conduction velocities. Microscopic examination of peripheral nerve biopsies (light and electron microscopy, teased nerve fibers), showed that this neuropathy was characterized by segmental demyelination and focally folded myelin sheaths. Various clinical syndromes associated with tomacula or focal thickening of the myelin sheath of the peripheral nerves have been described in humans and shown to be caused by gene mutations affecting the myelin proteins, such as the hereditary neuropathy with liability to pressure palsies or the demyelinating forms of Charcot-Marie-Tooth disease. In animals, a tomaculous neuropathy has been reported in cattle and chickens but not in carnivores. Here we report a demyelinating peripheral neuropathy with tomacula in two Miniature Schnauzer dogs.

Chronic ethanol exposure decreases CB1 receptor function at GABAergic synapses in the rat central amygdala

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Varodayan, Florence P.; Soni, Neeraj; Bajo, Michal

2016-01-01

release, and GABAergic dysregulation in the central nucleus of the amygdala (CeA) is critical in the transition to alcohol dependence. We investigated possible disruptions in CB1 signaling of rat CeA GABAergic transmission following intermittent ethanol exposure. In the CeA of alcohol-naive rats, CB1...

GABAergic Neuron-Specific Loss of Ube3a Causes Angelman Syndrome-Like EEG Abnormalities and Enhances Seizure Susceptibility.

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Judson, Matthew C; Wallace, Michael L; Sidorov, Michael S; Burette, Alain C; Gu, Bin; van Woerden, Geeske M; King, Ian F; Han, Ji Eun; Zylka, Mark J; Elgersma, Ype; Weinberg, Richard J; Philpot, Benjamin D

2016-04-06

Loss of maternal UBE3A causes Angelman syndrome (AS), a neurodevelopmental disorder associated with severe epilepsy. We previously implicated GABAergic deficits onto layer (L) 2/3 pyramidal neurons in the pathogenesis of neocortical hyperexcitability, and perhaps epilepsy, in AS model mice. Here we investigate consequences of selective Ube3a loss from either GABAergic or glutamatergic neurons, focusing on the development of hyperexcitability within L2/3 neocortex and in broader circuit and behavioral contexts. We find that GABAergic Ube3a loss causes AS-like increases in neocortical EEG delta power, enhances seizure susceptibility, and leads to presynaptic accumulation of clathrin-coated vesicles (CCVs)-all without decreasing GABAergic inhibition onto L2/3 pyramidal neurons. Conversely, glutamatergic Ube3a loss fails to yield EEG abnormalities, seizures, or associated CCV phenotypes, despite impairing tonic inhibition onto L2/3 pyramidal neurons. These results substantiate GABAergic Ube3a loss as the principal cause of circuit hyperexcitability in AS mice, lending insight into ictogenic mechanisms in AS. Copyright © 2016 Elsevier Inc. All rights reserved.

Cytosolic Accumulation of L-Proline Disrupts GABA-Ergic Transmission through GAD Blockade

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Gregg W. Crabtree

2016-10-01

Full Text Available Proline dehydrogenase (PRODH, which degrades L-proline, resides within the schizophrenia-linked 22q11.2 deletion suggesting a role in disease. Supporting this, elevated L-proline levels have been shown to increase risk for psychotic disorders. Despite the strength of data linking PRODH and L-proline to neuropsychiatric diseases, targets of disease-relevant concentrations of L-proline have not been convincingly described. Here, we show that Prodh-deficient mice with elevated CNS L-proline display specific deficits in high-frequency GABA-ergic transmission and gamma-band oscillations. We find that L-proline is a GABA-mimetic and can act at multiple GABA-ergic targets. However, at disease-relevant concentrations, GABA-mimesis is limited to competitive blockade of glutamate decarboxylase leading to reduced GABA production. Significantly, deficits in GABA-ergic transmission are reversed by enhancing net GABA production with the clinically relevant compound vigabatrin. These findings indicate that accumulation of a neuroactive metabolite can lead to molecular and synaptic dysfunction and help to understand mechanisms underlying neuropsychiatric disease.

Cytosolic Accumulation of L-Proline Disrupts GABA-Ergic Transmission through GAD Blockade.

Science.gov (United States)

Crabtree, Gregg W; Park, Alan J; Gordon, Joshua A; Gogos, Joseph A

2016-10-04

Proline dehydrogenase (PRODH), which degrades L-proline, resides within the schizophrenia-linked 22q11.2 deletion suggesting a role in disease. Supporting this, elevated L-proline levels have been shown to increase risk for psychotic disorders. Despite the strength of data linking PRODH and L-proline to neuropsychiatric diseases, targets of disease-relevant concentrations of L-proline have not been convincingly described. Here, we show that Prodh-deficient mice with elevated CNS L-proline display specific deficits in high-frequency GABA-ergic transmission and gamma-band oscillations. We find that L-proline is a GABA-mimetic and can act at multiple GABA-ergic targets. However, at disease-relevant concentrations, GABA-mimesis is limited to competitive blockade of glutamate decarboxylase leading to reduced GABA production. Significantly, deficits in GABA-ergic transmission are reversed by enhancing net GABA production with the clinically relevant compound vigabatrin. These findings indicate that accumulation of a neuroactive metabolite can lead to molecular and synaptic dysfunction and help to understand mechanisms underlying neuropsychiatric disease. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Recruitment of Perisomatic Inhibition during Spontaneous Hippocampal Activity In Vitro.

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Anna Beyeler

Full Text Available It was recently shown that perisomatic GABAergic inhibitory postsynaptic potentials (IPSPs originating from basket and chandelier cells can be recorded as population IPSPs from the hippocampal pyramidal layer using extracellular electrodes (eIPSPs. Taking advantage of this approach, we have investigated the recruitment of perisomatic inhibition during spontaneous hippocampal activity in vitro. Combining intracellular and extracellular recordings from pyramidal cells and interneurons, we confirm that inhibitory signals generated by basket cells can be recorded extracellularly, but our results suggest that, during spontaneous activity, eIPSPs are mostly confined to the CA3 rather than CA1 region. CA3 eIPSPs produced the powerful time-locked inhibition of multi-unit activity expected from perisomatic inhibition. Analysis of the temporal dynamics of spike discharges relative to eIPSPs suggests significant but moderate recruitment of excitatory and inhibitory neurons within the CA3 network on a 10 ms time scale, within which neurons recruit each other through recurrent collaterals and trigger powerful feedback inhibition. Such quantified parameters of neuronal interactions in the hippocampal network may serve as a basis for future characterisation of pathological conditions potentially affecting the interactions between excitation and inhibition in this circuit.

A Method to Culture GABAergic Interneurons Derived from the Medial Ganglionic Eminence

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Sira A. Franchi

2018-01-01

Full Text Available Understanding the mechanisms guiding interneuron development is a central aspect of the current research on cortical/hippocampal interneurons, which is highly relevant to brain function and pathology. In this methodological study we have addressed the setup of protocols for the reproducible culture of dissociated cells from murine medial ganglionic eminences (MGEs, to provide a culture system for the analysis of interneurons in vitro. This study includes the detailed protocols for the preparation of the dissociated cells, and for their culture on optimal substrates for cell migration or differentiation. These cultures enriched in interneurons may allow the investigation of the migratory behavior of interneuron precursors and their differentiation in vitro, up to the formation of morphologically identifiable GABAergic synapses. Live imaging of MGE–derived cells plated on proper substrates shows that they are useful to study the migratory behavior of the precursors, as well as the behavior of growth cones during the development of neurites. Most MGE-derived precursors develop into polarized GABAergic interneurons as determined by axonal, dendritic, and GABAergic markers. We present also a comparison of cells from WT and mutant mice as a proof of principle for the use of these cultures for the analysis of the migration and differentiation of GABAergic cells with different genetic backgrounds. The culture enriched in interneurons described here represents a useful experimental system to examine in a relatively easy and fast way the morpho-functional properties of these cells under physiological or pathological conditions, providing a powerful tool to complement the studies in vivo.

Spatio-temporal specialization of GABAergic septo-hippocampal neurons for rhythmic network activity.

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Unal, Gunes; Crump, Michael G; Viney, Tim J; Éltes, Tímea; Katona, Linda; Klausberger, Thomas; Somogyi, Peter

2018-03-03

Medial septal GABAergic neurons of the basal forebrain innervate the hippocampus and related cortical areas, contributing to the coordination of network activity, such as theta oscillations and sharp wave-ripple events, via a preferential innervation of GABAergic interneurons. Individual medial septal neurons display diverse activity patterns, which may be related to their termination in different cortical areas and/or to the different types of innervated interneurons. To test these hypotheses, we extracellularly recorded and juxtacellularly labeled single medial septal neurons in anesthetized rats in vivo during hippocampal theta and ripple oscillations, traced their axons to distant cortical target areas, and analyzed their postsynaptic interneurons. Medial septal GABAergic neurons exhibiting different hippocampal theta phase preferences and/or sharp wave-ripple related activity terminated in restricted hippocampal regions, and selectively targeted a limited number of interneuron types, as established on the basis of molecular markers. We demonstrate the preferential innervation of bistratified cells in CA1 and of basket cells in CA3 by individual axons. One group of septal neurons was suppressed during sharp wave-ripples, maintained their firing rate across theta and non-theta network states and mainly fired along the descending phase of CA1 theta oscillations. In contrast, neurons that were active during sharp wave-ripples increased their firing significantly during "theta" compared to "non-theta" states, with most firing during the ascending phase of theta oscillations. These results demonstrate that specialized septal GABAergic neurons contribute to the coordination of network activity through parallel, target area- and cell type-selective projections to the hippocampus.

The Whole new world of miniature technology

Energy Technology Data Exchange (ETDEWEB)

Gillespie, L.K.

1980-07-01

In the past ten years, miniaturization of both electrical and mechanical parts has significantly increased. Documentation of the design and production capabilities of miniaturization in the electronics industry is well-defined. Literature on the subject of miniaturization of metal piece parts, however, is hard to find. Some of the current capabilities in the manufacture of miniature metal piece parts or miniature features in larger piece parts are discussed.

Mice deficient in transmembrane prostatic acid phosphatase display increased GABAergic transmission and neurological alterations.

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Heidi O Nousiainen

Full Text Available Prostatic acid phosphatase (PAP, the first diagnostic marker and present therapeutic target for prostate cancer, modulates nociception at the dorsal root ganglia (DRG, but its function in the central nervous system has remained unknown. We studied expression and function of TMPAP (the transmembrane isoform of PAP in the brain by utilizing mice deficient in TMPAP (PAP-/- mice. Here we report that TMPAP is expressed in a subpopulation of cerebral GABAergic neurons, and mice deficient in TMPAP show multiple behavioral and neurochemical features linked to hyperdopaminergic dysregulation and altered GABAergic transmission. In addition to increased anxiety, disturbed prepulse inhibition, increased synthesis of striatal dopamine, and augmented response to amphetamine, PAP-deficient mice have enlarged lateral ventricles, reduced diazepam-induced loss of righting reflex, and increased GABAergic tone in the hippocampus. TMPAP in the mouse brain is localized presynaptically, and colocalized with SNARE-associated protein snapin, a protein involved in synaptic vesicle docking and fusion, and PAP-deficient mice display altered subcellular distribution of snapin. We have previously shown TMPAP to reside in prostatic exosomes and we propose that TMPAP is involved in the control of GABAergic tone in the brain also through exocytosis, and that PAP deficiency produces a distinct neurological phenotype.

Effects of Hypocretin/Orexin and Major Transmitters of Arousal on Fast Spiking Neurons in Mouse Cortical Layer 6B.

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Wenger Combremont, Anne-Laure; Bayer, Laurence; Dupré, Anouk; Mühlethaler, Michel; Serafin, Mauro

2016-08-01

Fast spiking (FS) GABAergic neurons are thought to be involved in the generation of high-frequency cortical rhythms during the waking state. We previously showed that cortical layer 6b (L6b) was a specific target for the wake-promoting transmitter, hypocretin/orexin (hcrt/orx). Here, we have investigated whether L6b FS cells were sensitive to hcrt/orx and other transmitters associated with cortical activation. Recordings were thus made from L6b FS cells in either wild-type mice or in transgenic mice in which GFP-positive GABAergic cells are parvalbumin positive. Whereas in a control condition hcrt/orx induced a strong increase in the frequency, but not amplitude, of spontaneous synaptic currents, in the presence of TTX, it had no effect at all on miniature synaptic currents. Hcrt/orx effect was thus presynaptic although not by an action on glutamatergic terminals but rather on neighboring cells. In contrast, noradrenaline and acetylcholine depolarized and excited these cells through a direct postsynaptic action. Neurotensin, which is colocalized in hcrt/orx neurons, also depolarized and excited these cells but the effect was indirect. Morphologically, these cells exhibited basket-like features. These results suggest that hcrt/orx, noradrenaline, acetylcholine, and neurotensin could contribute to high-frequency cortical activity through an action on L6b GABAergic FS cells. © The Author 2016. Published by Oxford University Press.

Myeloid leukemias and virally induced lymphomas in miniature inbred swine; development of a large animal tumor model

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RAIMON eDURAN-STRUUCK

2015-11-01

Full Text Available The lack of a large animal transplantable tumor model has limited the study of novel therapeutic strategies for the treatment of liquid cancers. Swine as a species provide a natural option based on their similarities with humans and their already extensive use in biomedical research. Specifically, the MGH miniature swine herd retains unique genetic characteristics that facilitate the study of hematopoietic cell and solid organ transplantation. Spontaneously arising liquid cancers in these swine, specifically myeloid leukemias and B cell lymphomas, closely resemble human malignancies. The ability to establish aggressive tumor cell lines in vitro from these naturally occurring malignancies makes a transplantable tumor model a close reality. Here, we discuss our experience with myeloid and lymphoid tumors in MHC characterized miniature swine and future approaches regarding the development of a large animal transplantable tumor model.

GABAergic Mechanisms in Schizophrenia : Linking Postmortem and In Vivo Studies

NARCIS (Netherlands)

de Jonge, Jeroen C; Vinkers, Christiaan H; Hulshoff Pol, Hilleke E; Marsman, Anouk

2017-01-01

Schizophrenia is a psychiatric disorder characterized by hallucinations, delusions, disorganized thinking, and impairments in cognitive functioning. Evidence from postmortem studies suggests that alterations in cortical γ-aminobutyric acid (GABAergic) neurons contribute to the clinical features of

Miniature Optical Isolator, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — To address NASA's need for miniature optical isolators in atom interferometry applications, Physical Optics Corporation (POC) proposes to develop a miniature optical...

The role of spinal GABAergic circuits in the control of phrenic nerve motor output.

Science.gov (United States)

Marchenko, Vitaliy; Ghali, Michael G Z; Rogers, Robert F

2015-06-01

While supraspinal mechanisms underlying respiratory pattern formation are well characterized, the contribution of spinal circuitry to the same remains poorly understood. In this study, we tested the hypothesis that intraspinal GABAergic circuits are involved in shaping phrenic motor output. To this end, we performed bilateral phrenic nerve recordings in anesthetized adult rats and observed neurogram changes in response to knocking down expression of both isoforms (65 and 67 kDa) of glutamate decarboxylase (GAD65/67) using microinjections of anti-GAD65/67 short-interference RNA (siRNA) in the phrenic nucleus. The number of GAD65/67-positive cells was drastically reduced on the side of siRNA microinjections, especially in the lateral aspects of Rexed's laminae VII and IX in the ventral horn of cervical segment C4, but not contralateral to microinjections. We hypothesize that intraspinal GABAergic control of phrenic output is primarily phasic, but also plays an important role in tonic regulation of phrenic discharge. Also, we identified respiration-modulated GABAergic interneurons (both inspiratory and expiratory) located slightly dorsal to the phrenic nucleus. Our data provide the first direct evidence for the existence of intraspinal GABAergic circuits contributing to the formation of phrenic output. The physiological role of local intraspinal inhibition, independent of descending direct bulbospinal control, is discussed. Copyright © 2015 the American Physiological Society.

Impact of perinatal asphyxia on the GABAergic and locomotor system.

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Van de Berg, W D J; Kwaijtaal, M; de Louw, A J A; Lissone, N P A; Schmitz, C; Faull, R L M; Blokland, A; Blanco, C E; Steinbusch, H W M

2003-01-01

Perinatal asphyxia can cause neuronal loss and depletion of neurotransmitters within the striatum. The striatum plays an important role in motor control, sensorimotor integration and learning. In the present study we investigated whether perinatal asphyxia leads to motor deficits related to striatal damage, and in particular to the loss of GABAergic neurons. Perinatal asphyxia was induced in time-pregnant Wistar rats on the day of delivery by placing the uterus horns, containing the pups, in a 37 degrees C water bath for 20 min. Three motor performance tasks (open field, grip test and walking pattern) were performed at 3 and 6 weeks of age. Antibodies against calbindin and parvalbumin were used to stain GABAergic striatal projection neurons and interneurons, respectively. The motor tests revealed subtle effects of perinatal asphyxia, i.e. small decrease in motor activity. Analysis of the walking pattern revealed an increase in stride width at 6 weeks of age after perinatal asphyxia. Furthermore, a substantial loss of calbindin-immunoreactive (-22%) and parvalbumin-immunoreactive (-43%) cells was found in the striatum following perinatal asphyxia at two months of age. GABA(A) receptor autoradiography revealed no changes in GABA binding activity within the striatum, globus pallidus or substantia nigra. We conclude that perinatal asphyxia resulted in a loss of GABAergic projection neurons and interneurons in the striatum without alteration of GABA(A) receptor affinity. Despite a considerable loss of striatal neurons, only minor deficits in motor performance were found after perinatal asphyxia.

Inhibitory neurons modulate spontaneous signaling in cultured cortical neurons: density-dependent regulation of excitatory neuronal signaling

International Nuclear Information System (INIS)

Serra, Michael; Guaraldi, Mary; Shea, Thomas B

2010-01-01

Cortical neuronal activity depends on a balance between excitatory and inhibitory influences. Culturing of neurons on multi-electrode arrays (MEAs) has provided insight into the development and maintenance of neuronal networks. Herein, we seeded MEAs with murine embryonic cortical/hippocampal neurons at different densities ( 1000 cells mm −2 ) and monitored resultant spontaneous signaling. Sparsely seeded cultures displayed a large number of bipolar, rapid, high-amplitude individual signals with no apparent temporal regularity. By contrast, densely seeded cultures instead displayed clusters of signals at regular intervals. These patterns were observed even within thinner and thicker areas of the same culture. GABAergic neurons (25% of total neurons in our cultures) mediated the differential signal patterns observed above, since addition of the inhibitory antagonist bicuculline to dense cultures and hippocampal slice cultures induced the signal pattern characteristic of sparse cultures. Sparsely seeded cultures likely lacked sufficient inhibitory neurons to modulate excitatory activity. Differential seeding of MEAs can provide a unique model for analyses of pertubation in the interaction between excitatory and inhibitory function during aging and neuropathological conditions where dysregulation of GABAergic neurons is a significant component

Dr.Johnson's Dictionary in Miniature

OpenAIRE

Imazato, Chiaki

1988-01-01

More than hundred 'Johnson's' dictionaries have so far been published not only in English but in other countries, and there are numerous books and articles on Johnson's Dictionary. But few have referred to Johnson's Dictionary in Miniature; nor were there any books or articles on it. Fortunately, however, I've got one copy of Johnson's Dictionary in Miniature, which was published in 1806. Johnson's Dictionary (1755) has 41,677 entries, whereas Johnson's Dictionary in Miniature 23,439 entr...

Quantitative Study of NPY-Expressing GABAergic Neurons and Axons in Rat Spinal Dorsal Horn*

OpenAIRE

Polg?r, Erika; Sardella, Thomas CP; Watanabe, Masahiko; Todd, Andrew J

2010-01-01

Between 25?40% of neurons in laminae I?III are GABAergic, and some of these express neuropeptide Y (NPY). We previously reported that NPY-immunoreactive axons form numerous synapses on lamina III projection neurons that possess the neurokinin 1 receptor (NK1r). The aims of this study were to determine the proportion of neurons and GABAergic boutons in this region that contain NPY, and to look for evidence that they selectively innervate different neuronal populations. We found that 4?6% of ne...

Modulation of GABAergic Transmission in Development and Neurodevelopmental Disorders: Investigating Physiology and Pathology to Gain Therapeutic Perspectives

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Gabriele eDeidda

2014-05-01

Full Text Available During mammalian ontogenesis, the neurotransmitter GABA is a fundamental regulator of neuronal networks. In neuronal development, GABAergic signaling regulates neural proliferation, migration, differentiation, and neuronal-network wiring. In the adult, GABA orchestrates the activity of different neuronal cell-types largely interconnected, by powerfully modulating synaptic activity. GABA exerts these functions by binding to chloride-permeable ionotropic GABAA receptors and metabotropic GABAB receptors. According to its functional importance during development, GABA is implicated in a number of neurodevelopmental disorders such as autism, Fragile X, Rett syndrome, Down syndrome, schizophrenia, Tourette's syndrome and neurofibromatosis.The strength and polarity of GABAergic transmission is continuously modulated during physiological, but also pathological conditions. For GABAergic transmission through GABAA receptors, strength regulation is achieved by different mechanisms such as modulation of GABAA receptors themselves, variation of intracellular chloride concentration, and alteration in GABA metabolism. In the never-ending effort to find possible treatments for GABA-related neurological diseases, of great importance would be modulating GABAergic transmission in a safe and possibly physiological way, without the dangers of either silencing network activity or causing epileptic seizures. In this review, we will discuss the different ways to modulate GABAergic transmission normally at work both during physiological and pathological conditions. Our aim is to highlight new research perspectives for therapeutic treatments that reinstate natural and physiological brain functions in neuro-pathological conditions.

Optogenetic activation of leptin- and glucose-regulated GABAergic neurons in dorsomedial hypothalamus promotes food intake via inhibitory synaptic transmission to paraventricular nucleus of hypothalamus

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Zesemdorj Otgon-Uul

2016-08-01

Full Text Available Objective: The dorsomedial hypothalamus (DMH has been considered an orexigenic nucleus, since the DMH lesion reduced food intake and body weight and induced resistance to diet-induced obesity. The DMH expresses feeding regulatory neuropeptides and receptors including neuropeptide Y (NPY, cocaine- and amphetamine-regulated transcript (CART, cholecystokinin (CCK, leptin receptor, and melanocortin 3/4 receptors. However, the principal neurons generating the orexigenic function in the DMH remain to be defined. This study aimed to clarify the role of the DMH GABAergic neurons in feeding regulation by using optogenetics and electrophysiological techniques. Methods: We generated the mice expressing ChRFR-C167A, a bistable chimeric channelrhodopsin, selectively in GABAergic neurons of DMH via locally injected adeno-associated virus 2. Food intake after optogenetic activation of DMH GABAergic neurons was measured. Electrophysiological properties of DMH GABAergic neurons were measured using slice patch clamp. Results: Optogenetic activation of DMH GABAergic neurons promoted food intake. Leptin hyperpolarized and lowering glucose depolarized half of DMH GABAergic neurons, suggesting their orexigenic property. Optical activation of axonal terminals of DMH GABAergic neurons at the paraventricular nucleus of hypothalamus (PVN, where anorexigenic neurons are localized, increased inhibitory postsynaptic currents on PVN neurons and promoted food intake. Conclusion: DMH GABAergic neurons are regulated by metabolic signals leptin and glucose and, once activated, promote food intake via inhibitory synaptic transmission to PVN. Keywords: Dorsomedial hypothalamus, GABAergic neuron, Feeding, Leptin, Glucose, Optogenetics

Dopamine synapse is a neuroligin-2–mediated contact between dopaminergic presynaptic and GABAergic postsynaptic structures

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Uchigashima, Motokazu; Ohtsuka, Toshihisa; Kobayashi, Kazuto; Watanabe, Masahiko

2016-01-01

Midbrain dopamine neurons project densely to the striatum and form so-called dopamine synapses on medium spiny neurons (MSNs), principal neurons in the striatum. Because dopamine receptors are widely expressed away from dopamine synapses, it remains unclear how dopamine synapses are involved in dopaminergic transmission. Here we demonstrate that dopamine synapses are contacts formed between dopaminergic presynaptic and GABAergic postsynaptic structures. The presynaptic structure expressed tyrosine hydroxylase, vesicular monoamine transporter-2, and plasmalemmal dopamine transporter, which are essential for dopamine synthesis, vesicular filling, and recycling, but was below the detection threshold for molecules involving GABA synthesis and vesicular filling or for GABA itself. In contrast, the postsynaptic structure of dopamine synapses expressed GABAergic molecules, including postsynaptic adhesion molecule neuroligin-2, postsynaptic scaffolding molecule gephyrin, and GABAA receptor α1, without any specific clustering of dopamine receptors. Of these, neuroligin-2 promoted presynaptic differentiation in axons of midbrain dopamine neurons and striatal GABAergic neurons in culture. After neuroligin-2 knockdown in the striatum, a significant decrease of dopamine synapses coupled with a reciprocal increase of GABAergic synapses was observed on MSN dendrites. This finding suggests that neuroligin-2 controls striatal synapse formation by giving competitive advantage to heterologous dopamine synapses over conventional GABAergic synapses. Considering that MSN dendrites are preferential targets of dopamine synapses and express high levels of dopamine receptors, dopamine synapse formation may serve to increase the specificity and potency of dopaminergic modulation of striatal outputs by anchoring dopamine release sites to dopamine-sensing targets. PMID:27035941

Development of GPCR modulation of GABAergic transmission in chicken nucleus laminaris neurons.

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Zheng-Quan Tang

Full Text Available Neurons in the nucleus laminaris (NL of birds act as coincidence detectors and encode interaural time difference to localize the sound source in the azimuth plane. GABAergic transmission in a number of CNS nuclei including the NL is subject to a dual modulation by presynaptic GABA(B receptors (GABA(BRs and metabotropic glutamate receptors (mGluRs. Here, using in vitro whole-cell patch clamp recordings from acute brain slices of the chick, we characterized the following important but unknown properties pertaining to such a dual modulation: (1 emergence of functional GABA synapses in NL neurons; (2 the temporal onset of neuromodulation mediated by GABA(BRs and mGluRs; and (3 the physiological conditions under which GABA(BRs and mGluRs are activated by endogenous transmitters. We found that (1 GABA(AR-mediated synaptic responses were observed in about half of the neurons at embryonic day 11 (E11; (2 GABA(BR-mediated modulation of the GABAergic transmission was detectable at E11, whereas the modulation by mGluRs did not emerge until E15; and (3 endogenous activity of GABA(BRs was induced by both low- (5 or 10 Hz and high-frequency (200 Hz stimulation of the GABAergic pathway, whereas endogenous activity of mGluRs was induced by high- (200 Hz but not low-frequency (5 or 10 Hz stimulation of the glutamatergic pathway. Furthermore, the endogenous activity of mGluRs was mediated by group II but not group III members. Therefore, autoreceptor-mediated modulation of GABAergic transmission emerges at the same time when the GABA synapses become functional. Heteroreceptor-mediated modulation appears at a later time and is receptor type dependent in vitro.

Histamine facilitates GABAergic transmission in the rat entorhinal cortex: Roles of H1 and H2 receptors, Na+ -permeable cation channels, and inward rectifier K+ channels.

Science.gov (United States)

Cilz, Nicholas I; Lei, Saobo

2017-05-01

In the brain, histamine (HA) serves as a neuromodulator and a neurotransmitter released from the tuberomammillary nucleus (TMN). HA is involved in wakefulness, thermoregulation, energy homeostasis, nociception, and learning and memory. The medial entorhinal cortex (MEC) receives inputs from the TMN and expresses HA receptors (H 1 , H 2 , and H 3 ). We investigated the effects of HA on GABAergic transmission in the MEC and found that HA significantly increased the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) with an EC 50 of 1.3 µM, but failed to significantly alter sIPSC amplitude. HA-induced increases in sIPSC frequency were sensitive to tetrodotoxin (TTX), required extracellular Ca 2+ , and persisted when GDP-β-S, a G-protein inactivator, was applied postsynaptically via the recording pipettes, indicating that HA increased GABA release by facilitating the excitability of GABAergic interneurons in the MEC. Recordings from local MEC interneurons revealed that HA significantly increased their excitability as determined by membrane depolarization, generation of an inward current at -65 mV, and augmentation of action potential firing frequency. Both H 1 and H 2 receptors were involved in HA-induced increases in sIPSCs and interneuron excitability. Immunohistochemical staining showed that both H 1 and H 2 receptors are expressed on GABAergic interneurons in the MEC. HA-induced depolarization of interneurons involved a mixed ionic mechanism including activation of a Na + -permeable cation channel and inhibition of a cesium-sensitive inward rectifier K + channel, although HA also inhibited the delayed rectifier K + channels. Our results may provide a cellular mechanism, at least partially, to explain the roles of HA in the brain. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Quasi-morphine abstinence behaviour GABA-ergic mechanisms and their localization

NARCIS (Netherlands)

J.W. van der Laan

1981-01-01

textabstractDi-n-propylacetate (DPA), generally known to be an anti-epileptic drug, induces a behavioural syndrome in rats resembling morphine abstinence behaviour, which is called, therefore, quasi-morphine abstinence beh~viour. An increase in GABA-ergic activity is probably responsible for this

Hypocretin (orexin) regulates glutamate input to fast-spiking interneurons in layer V of the Fr2 region of the murine prefrontal cortex.

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Aracri, Patrizia; Banfi, Daniele; Pasini, Maria Enrica; Amadeo, Alida; Becchetti, Andrea

2015-05-01

We studied the effect of hypocretin 1 (orexin A) in the frontal area 2 (Fr2) of the murine neocortex, implicated in the motivation-dependent goal-directed tasks. In layer V, hypocretin stimulated the spontaneous excitatory postsynaptic currents (EPSCs) on fast-spiking (FS) interneurons. The effect was accompanied by increased frequency of miniature EPSCs, indicating that hypocretin can target the glutamatergic terminals. Moreover, hypocretin stimulated the spontaneous inhibitory postsynaptic currents (IPSCs) on pyramidal neurons, with no effect on miniature IPSCs. This action was prevented by blocking 1) the ionotropic glutamatergic receptors; 2) the hypocretin receptor type 1 (HCRTR-1), with SB-334867. Finally, hypocretin increased the firing frequency in FS cells, and the effect was blocked when the ionotropic glutamate transmission was inhibited. Immunolocalization confirmed that HCRTR-1 is highly expressed in Fr2, particularly in layer V-VI. Conspicuous labeling was observed in pyramidal neuron somata and in VGLUT1+ glutamatergic terminals, but not in VGLUT2+ fibers (mainly thalamocortical afferents). The expression of HCRTR-1 in GABAergic structures was scarce. We conclude that 1) hypocretin regulates glutamate release in Fr2; 2) the effect presents a presynaptic component; 3) the peptide control of FS cells is indirect, and probably mediated by the regulation of glutamatergic input onto these cells. © The Author 2013. Published by Oxford University Press.

The miniature accelerator

CERN Multimedia

Antonella Del Rosso

2015-01-01

The image that most people have of CERN is of its enormous accelerators and their capacity to accelerate particles to extremely high energies. But thanks to some cutting-edge studies on beam dynamics and radiofrequency technology, along with innovative construction techniques, teams at CERN have now created the first module of a brand-new accelerator, which will be just 2 metres long. The potential uses of this miniature accelerator will include deployment in hospitals for the production of medical isotopes and the treatment of cancer. It’s a real David-and-Goliath story.   Serge Mathot, in charge of the construction of the "mini-RFQ", pictured with the first of the four modules that will make up the miniature accelerator. The miniature accelerator consists of a radiofrequency quadrupole (RFQ), a component found at the start of all proton accelerator chains around the world, from the smallest to the largest. The LHC is designed to produce very high-intensity beams ...

[Effect of stimulation of GABA-ergic structures of the substantia nigra and caudate nucleus on food-getting behavior in the cat].

Science.gov (United States)

Shugalev, N P

1983-01-01

A study was made of the functional significance of GABA-ergic structures of the substantia nigra (SN) and the caudate nucleus (CN) and their role in food-procuring behaviour of cats. Analysis was made of behavioral and EEG-effects of local GABA and the GABA antagonist, picrotoxin, microinjections into the studied brain structures. Stimulation of the GABA-ergic structures of the SN produced a sedative effect and depression of the cat food-procuring behaviour. Effects of stimulation of the CN GABA-ergic structures were to a great degree reverse. The conclusion has been made that GABA-ergic structures of the SN and the CN play different roles in controlling the CN inhibitory influence upon food-procuring behaviour.

Strange Animals and Creatures in Islamic Miniatures: Focusing on Miniatures of the Conference of the Birds

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Neda Rohani

2017-09-01

Full Text Available Strange animals and creatures have always existed in every mythological culture. In Iran's pre-Islamic and post-Islamic miniatures and reliefs, there are many strange animals and creatures such as dragons and phoenix which were associated with the Iranian culture and civilization. Because of presence of these strange creatures, particularly human life, these creatures are first used in mythological life and then symbolically to express human ideas. However, these animals were present in both mythology and epics and, later in the Islamic era, in the mystical stories, educational stories and admonishing anecdotes like Sanai, Attar, and Rumi. This study tends to investigate genealogy of strange animals and creatures in ancient Iranian reliefs and their continued presence in miniatures of Islamic era as well as presence of these creatures in miniatures which are based on Attar’s Conference of the Birds. In fact, this study reviews elements and symbolic concepts of animals, allowing a deeper understanding of function of elements and symbolism in works of Iranian miniaturists. Contemplation of miniatures, icons and the relationship between literature and miniatures will lead to many results in recognition of mystical intellectual foundations. Therefore, this study tends to investigate mysterious and unknown aspects of Iranian miniatures and find their relationship with culture and stories.

Cell Type-specific Intrinsic Perithreshold Oscillations in Hippocampal GABAergic Interneurons.

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Kang, Young-Jin; Lewis, Hannah Elisabeth Smashey; Young, Mason William; Govindaiah, Gubbi; Greenfield, Lazar John; Garcia-Rill, Edgar; Lee, Sang-Hun

2018-04-15

The hippocampus plays a critical role in learning, memory, and spatial processing through coordinated network activity including theta and gamma oscillations. Recent evidence suggests that hippocampal subregions (e.g., CA1) can generate these oscillations at the network level, at least in part, through GABAergic interneurons. However, it is unclear whether specific GABAergic interneurons generate intrinsic theta and/or gamma oscillations at the single-cell level. Since major types of CA1 interneurons (i.e., parvalbumin-positive basket cells (PVBCs), cannabinoid type 1 receptor-positive basket cells (CB 1 BCs), Schaffer collateral-associated cells (SCAs), neurogliaform cells and ivy cells) are thought to play key roles in network theta and gamma oscillations in the hippocampus, we tested the hypothesis that these cells generate intrinsic perithreshold oscillations at the single-cell level. We performed whole-cell patch-clamp recordings from GABAergic interneurons in the CA1 region of the mouse hippocampus in the presence of synaptic blockers to identify intrinsic perithreshold membrane potential oscillations. The majority of PVBCs (83%), but not the other interneuron subtypes, produced intrinsic perithreshold gamma oscillations if the membrane potential remained above -45 mV. In contrast, CB 1 BCs, SCAs, neurogliaform cells, ivy cells, and the remaining PVBCs (17%) produced intrinsic theta, but not gamma, oscillations. These oscillations were prevented by blockers of persistent sodium current. These data demonstrate that the major types of hippocampal interneurons produce distinct frequency bands of intrinsic perithreshold membrane oscillations. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Functional diversity of supragranular GABAergic neurons in the barrel cortex

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Luc J Gentet

2012-08-01

Full Text Available Although the neocortex forms a distributed system comprised of several functional areas, its vertical columnar organization is largely conserved across areas and species, suggesting the existence of a canonical neocortical microcircuit. In order to elucidate the principles governing the organization of such a cortical diagram, a detailed understanding of the dynamics binding different types of cortical neurons into a coherent algorithm is essential. Within this complex circuitry, GABAergic interneurons, while forming approximately only 15-20% of all cortical neurons, appear critical in maintaining a dynamic balance between excitation and inhibition. Despite their importance, cortical GABAergic neurons have not been extensively studied in vivo and their precise role in shaping the local microcircuit sensory response still remains to be determined. Their paucity, combined with their molecular, anatomical and physiological diversity, has made it difficult to even establish a consensual nomenclature.However, recent technological advances in microscopy and mouse genetics have fostered a renewed interest in neocortical interneurons by putting them within visible reach of experimenters. The anatomically well-defined whisker-to-barrel pathway of the rodent is particularly amenable to studies attempting to link cortical circuit dynamics to behavior. To each whisker corresponds a discrete cortical unit equivalent to a single column, specialized in the encoding and processing of the sensory information it receives. In this review, we will focus on the functional role that each subtype of supragranular GABAergic neuron embedded within such a single neocortical unit may play in shaping the dynamics of the local circuit during somatosensory integration.

Visual thread quality for precision miniature mechanisms

Energy Technology Data Exchange (ETDEWEB)

Gillespie, L.K.

1981-04-01

Threaded features have eight visual appearance factors which can affect their function in precision miniature mechanisms. The Bendix practice in deburring, finishing, and accepting these conditions on miniature threads is described as is their impact in assemblies of precision miniature electromechanical assemblies.

Prenatal phencyclidine treatment induces behavioral deficits through impairment of GABAergic interneurons in the prefrontal cortex.

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Toriumi, Kazuya; Oki, Mika; Muto, Eriko; Tanaka, Junko; Mouri, Akihiro; Mamiya, Takayoshi; Kim, Hyoung-Chun; Nabeshima, Toshitaka

2016-06-01

We previously reported that prenatal treatment with phencyclidine (PCP) induces glutamatergic dysfunction in the prefrontal cortex (PFC), leading to schizophrenia-like behavioral deficits in adult mice. However, little is known about the prenatal effect of PCP treatment on other types of neurons. We focused on γ-aminobutyric acid (GABA)-ergic interneurons and evaluated the effect of prenatal PCP exposure on the neurodevelopment of GABAergic interneurons in the PFC. PCP was administered at the dose of 10 mg/kg/day to pregnant dams from embryonic day 6.5 to 18.5. After the pups were reared to adult, we analyzed their GABAergic system in the PFC using immunohistological, biochemical, and behavioral analyses in adulthood. The prenatal PCP treatment decreased the density of parvalbumin-positive cells and reduced the expression level of glutamic acid decarboxylase 67 (GAD67) and GABA content of the PFC in adults. Additionally, prenatal PCP treatment induced behavioral deficits in adult mice, such as hypersensitivity to PCP and prepulse inhibition (PPI) deficits. These behavioral deficits were ameliorated by pretreatment with the GABAB receptor agonist baclofen. Furthermore, the density of c-Fos-positive cells was decreased after the PPI test in the PFC of mice treated with PCP prenatally, and this effect was ameliorated by pretreatment with baclofen. These findings suggest that prenatal treatment with PCP induced GABAergic dysfunction in the PFC, which caused behavioral deficits.

Advances in Miniaturized Instruments for Genomics

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Cihun-Siyong Alex Gong

2014-01-01

Full Text Available In recent years, a lot of demonstrations of the miniaturized instruments were reported for genomic applications. They provided the advantages of miniaturization, automation, sensitivity, and specificity for the development of point-of-care diagnostics. The aim of this paper is to report on recent developments on miniaturized instruments for genomic applications. Based on the mature development of microfabrication, microfluidic systems have been demonstrated for various genomic detections. Since one of the objectives of miniaturized instruments is for the development of point-of-care device, impedimetric detection is found to be a promising technique for this purpose. An in-depth discussion of the impedimetric circuits and systems will be included to provide total consideration of the miniaturized instruments and their potential application towards real-time portable imaging in the “-omics” era. The current excellent demonstrations suggest a solid foundation for the development of practical and widespread point-of-care genomic diagnostic devices.

Distinct populations of GABAergic neurons in mouse rhombomere 1 express but do not require the homeodomain transcription factor PITX2.

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Waite, Mindy R; Skaggs, Kaia; Kaviany, Parisa; Skidmore, Jennifer M; Causeret, Frédéric; Martin, James F; Martin, Donna M

2012-01-01

Hindbrain rhombomere 1 (r1) is located caudal to the isthmus, a critical organizer region, and rostral to rhombomere 2 in the developing mouse brain. Dorsal r1 gives rise to the cerebellum, locus coeruleus, and several brainstem nuclei, whereas cells from ventral r1 contribute to the trochlear and trigeminal nuclei as well as serotonergic and GABAergic neurons of the dorsal raphe. Recent studies have identified several molecular events controlling dorsal r1 development. In contrast, very little is known about ventral r1 gene expression and the genetic mechanisms regulating its formation. Neurons with distinct neurotransmitter phenotypes have been identified in ventral r1 including GABAergic, serotonergic, and cholinergic neurons. Here we show that PITX2 marks a distinct population of GABAergic neurons in mouse embryonic ventral r1. This population appears to retain its GABAergic identity even in the absence of PITX2. We provide a comprehensive map of markers that places these PITX2-positive GABAergic neurons in a region of r1 that intersects and is potentially in communication with the dorsal raphe. Copyright © 2011 Elsevier Inc. All rights reserved.

Taurine activates GABAergic networks in the neocortex of immature mice

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Bogdan Aurel Sava

2014-02-01

Full Text Available Although it has been suggested that taurine is the main endogenous neurotransmitter acting on glycine receptors, the implications of glycine receptor-mediated taurine actions on immature neocortical networks have not been addressed yet. To investigate the influence of taurine on the excitability of neuronal networks in the immature neocortex, we performed whole-cell patch-clamp recordings from visually identified pyramidal neurons and interneurons in coronal slices from C57Bl/6 and GAD67-GFP transgenic mice (postnatal days 2-4. In 46 % of the pyramidal neurons bath-application of taurine at concentrations ≥ 300 mM significantly enhanced the frequency of postsynaptic currents (PSCs by 744.3 ± 93.8 % (n = 120 cells. This taurine-induced increase of PSC frequency was abolished by 0.2 mM tetrodotoxine, 1 mM strychnine or 3 mM gabazine, but was unaffected by the glutamatergic antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX and (± R(--3-(2-carboxypiperazine-4-yl-propyl-1-phosphonic acid (CPP, suggesting that taurine specifically activates GABAergic network activity projecting to pyramidal neurons. Cell-attached recordings revealed that taurine enhanced the frequency of action potentials in pyramidal neurons, indicating an excitatory action of the GABAergic PSCs. In order to identify the presynaptic targets of taurine we demonstrate that bath application of taurine induced in GAD67-GFP labeled interneurons an inward current that is mainly mediated by glycine receptors and can generate action potentials in these cells. We conclude from these results that taurine can enhance network excitability in the immature neocortex by selectively activating GABAergic interneurons via interactions with glycine receptors.

Specific rescue by ortho-hydroxy atorvastatin of cortical GABAergic neurons from previous oxygen/glucose deprivation: role of pCREB.

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Guirao, Verónica; Martí-Sistac, Octavi; DeGregorio-Rocasolano, Núria; Ponce, Jovita; Dávalos, Antoni; Gasull, Teresa

2017-11-01

The statin atorvastatin (ATV) given as a post-treatment has been reported beneficial in stroke, although the mechanisms involved are not well understood so far. Here, we investigated in vitro the effect of post-treatment with ATV and its main bioactive metabolite ortho-hydroxy ATV (o-ATV) on neuroprotection after oxygen and glucose deprivation (OGD), and the role of the pro-survival cAMP response element-binding protein (CREB). Post-OGD treatment of primary cultures of rat cortical neurons with o-ATV, but not ATV, provided neuroprotection to a specific subset of cortical neurons that were large and positive for glutamic acid decarboxylase (large-GAD (+) neurons, GABAergic). Significantly, only these GABAergic neurons showed an increase in phosphorylated CREB (pCREB) early after neuronal cultures were treated post-OGD with o-ATV. We found that o-ATV, but not ATV, increased the neuronal uptake of glutamate from the medium; this provides a rationale for the specific effect of o-ATV on pCREB in large-GABAergic neurons, which have a higher ratio of synaptic (pCREB-promoting) vs extrasynaptic (pCREB-reducing) N-methyl-D-aspartate (NMDA) receptors (NMDAR) than that of small-non-GABAergic neurons. When we pharmacologically increased pCREB levels post-OGD in non-GABAergic neurons, through the selective activation of synaptic NMDAR, we observed as well long-lasting neuronal survival. We propose that the statin metabolite o-ATV given post-OGD boosts the intrinsic pro-survival factor pCREB in large-GABAergic cortical neurons in vitro, this contributing to protect them from OGD. © 2017 International Society for Neurochemistry.

Ethanol affects network activity in cultured rat hippocampus: mediation by potassium channels.

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Eduard Korkotian

Full Text Available The effects of ethanol on neuronal network activity were studied in dissociated cultures of rat hippocampus. Exposure to low (0.25-0.5% ethanol concentrations caused an increase in synchronized network spikes, and a decrease in the duration of individual spikes. Ethanol also caused an increase in rate of miniature spontaneous excitatory postsynaptic currents. Higher concentrations of ethanol eliminated network spikes. These effects were reversible upon wash. The effects of the high, but not the low ethanol were blocked by the GABA antagonist bicuculline. The enhancing action of low ethanol was blocked by apamin, an SK potassium channel antagonist, and mimicked by 1-EBIO, an SK channel opener. It is proposed that in cultured hippocampal networks low concentration of ethanol is associated with SK channel activity, rather than the GABAergic receptor.

The Frequency-Dependent Aerobic Exercise Effects of Hypothalamic GABAergic Expression and Cardiovascular Functions in Aged Rats

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Yan Li

2017-06-01

Full Text Available A decline in cardiovascular modulation is a feature of the normal aging process and associated with cardiovascular diseases (CVDs such as hypertension and stroke. Exercise training is known to promote cardiovascular adaptation in young animals and positive effects on motor and cognitive capabilities, as well as on brain plasticity for all ages in mice. Here, we examine the question of whether aerobic exercise interventions may impact the GABAergic neurons of the paraventricular nucleus (PVN in aged rats which have been observed to have a decline in cardiovascular integration function. In the present study, young (2 months and old (24 months male Wistar rats were divided into young control (YC, old sedentary, old low frequency exercise (20 m/min, 60 min/day, 3 days/week, 12 weeks and old high frequency exercise (20 m/min, 60 min/day, 5 days/week, 12 weeks. Exercise training indexes were obtained, including resting heart rate (HR, blood pressure (BP, plasma norepinephrine (NE, and heart weight (HW-to-body weight (BW ratios. The brain was removed and processed according to the immunofluorescence staining and western blot used to analyze the GABAergic terminal density, the proteins of GAD67, GABAA receptor and gephyrin in the PVN. There were significant changes in aged rats compared with those in the YC. Twelve weeks aerobic exercise training has volume-dependent ameliorated effects on cardiovascular parameters, autonomic nervous activities and GABAergic system functions. These data suggest that the density of GABAergic declines in the PVN is associated with imbalance in autonomic nervous activities in normal aging. Additionally, aerobic exercise can rescue aging-related an overactivity of the sympathetic nervous system and induces modifications the resting BP and HR to lower values via improving the GABAergic system in the PVN.

The Frequency-Dependent Aerobic Exercise Effects of Hypothalamic GABAergic Expression and Cardiovascular Functions in Aged Rats

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Li, Yan; Zhao, Ziqi; Cai, Jiajia; Gu, Boya; Lv, Yuanyuan; Zhao, Li

2017-01-01

A decline in cardiovascular modulation is a feature of the normal aging process and associated with cardiovascular diseases (CVDs) such as hypertension and stroke. Exercise training is known to promote cardiovascular adaptation in young animals and positive effects on motor and cognitive capabilities, as well as on brain plasticity for all ages in mice. Here, we examine the question of whether aerobic exercise interventions may impact the GABAergic neurons of the paraventricular nucleus (PVN) in aged rats which have been observed to have a decline in cardiovascular integration function. In the present study, young (2 months) and old (24 months) male Wistar rats were divided into young control (YC), old sedentary, old low frequency exercise (20 m/min, 60 min/day, 3 days/week, 12 weeks) and old high frequency exercise (20 m/min, 60 min/day, 5 days/week, 12 weeks). Exercise training indexes were obtained, including resting heart rate (HR), blood pressure (BP), plasma norepinephrine (NE), and heart weight (HW)-to-body weight (BW) ratios. The brain was removed and processed according to the immunofluorescence staining and western blot used to analyze the GABAergic terminal density, the proteins of GAD67, GABAA receptor and gephyrin in the PVN. There were significant changes in aged rats compared with those in the YC. Twelve weeks aerobic exercise training has volume-dependent ameliorated effects on cardiovascular parameters, autonomic nervous activities and GABAergic system functions. These data suggest that the density of GABAergic declines in the PVN is associated with imbalance in autonomic nervous activities in normal aging. Additionally, aerobic exercise can rescue aging-related an overactivity of the sympathetic nervous system and induces modifications the resting BP and HR to lower values via improving the GABAergic system in the PVN. PMID:28713263

Effects of Repeated Stress on Age-Dependent GABAergic Regulation of the Lateral Nucleus of the Amygdala.

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Zhang, Wei; Rosenkranz, J Amiel

2016-08-01

The adolescent age is associated with lability of mood and emotion. The onset of depression and anxiety disorders peaks during adolescence and there are differences in symptomology during adolescence. This points to differences in the adolescent neural circuitry that underlies mood and emotion, such as the amygdala. The human adolescent amygdala is more responsive to evocative stimuli, hinting to less local inhibitory regulation of the amygdala, but this has not been explored in adolescents. The amygdala, including the lateral nucleus (LAT) of the basolateral amygdala complex, is sensitive to stress. The amygdala undergoes maturational processes during adolescence, and therefore may be more vulnerable to harmful effects of stress during this time period. However, little is known about the effects of stress on the LAT during adolescence. GABAergic inhibition is a key regulator of LAT activity. Therefore, the purpose of this study was to test whether there are differences in the local GABAergic regulation of the rat adolescent LAT, and differences in its sensitivity to repeated stress. We found that LAT projection neurons are subjected to weaker GABAergic inhibition during adolescence. Repeated stress reduced in vivo endogenous and exogenous GABAergic inhibition of LAT projection neurons in adolescent rats. Furthermore, repeated stress decreased measures of presynaptic GABA function and interneuron activity in adolescent rats. In contrast, repeated stress enhanced glutamatergic drive of LAT projection neurons in adult rats. These results demonstrate age differences in GABAergic regulation of the LAT, and age differences in the mechanism for the effects of repeated stress on LAT neuron activity. These findings provide a substrate for increased mood lability in adolescents, and provide a substrate by which adolescent repeated stress can induce distinct behavioral outcomes and psychiatric symptoms.

Cerebellar abiotrophy in a miniature schnauzer

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Berry, Michelle L.; Blas-Machado, Uriel

2003-01-01

A 3.5-month-old miniature schnauzer was presented for signs of progressive cerebellar ataxia. Necropsy revealed cerebellar abiotrophy. This is the first reported case of cerebellar abiotrophy in a purebred miniature schnauzer.

Cerebellar abiotrophy in a miniature schnauzer.

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Berry, Michelle L; Blas-Machado, Uriel

2003-08-01

A 3.5-month-old miniature schnauzer was presented for signs of progressive cerebellar ataxia. Necropsy revealed cerebellar abiotrophy. This is the first reported case of cerebellar abiotrophy in a purebred miniature schnauzer.

Glutamatergic and GABAergic neurotransmitter cycling and energy metabolism in rat cerebral cortex during postnatal development.

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Chowdhury, Golam M I; Patel, Anant B; Mason, Graeme F; Rothman, Douglas L; Behar, Kevin L

2007-12-01

The contribution of glutamatergic and gamma-aminobutyric acid (GABA)ergic neurons to oxidative energy metabolism and neurotransmission in the developing brain is not known. Glutamatergic and GABAergic fluxes were assessed in neocortex of postnatal day 10 (P10) and 30 (P30) urethane-anesthetized rats infused intravenously with [1,6-(13)C(2)]glucose for different time intervals (time course) or with [2-(13)C]acetate for 2 to 3 h (steady state). Amino acid levels and (13)C enrichments were determined in tissue extracts ex vivo using (1)H-[(13)C]-NMR spectroscopy. Metabolic fluxes were estimated from the best fits of a three-compartment metabolic model (glutamatergic neurons, GABAergic neurons, and astroglia) to the (13)C-enrichment time courses of amino acids from [1,6-(13)C(2)]glucose, constrained by the ratios of neurotransmitter cycling (V(cyc))-to-tricarboxylic acid (TCA) cycle flux (V(TCAn)) calculated from the steady-state [2-(13)C]acetate enrichment data. From P10 to P30 increases in total neuronal (glutamate plus GABA) TCA cycle flux (3 x ; 0.24+/-0.05 versus 0.71+/-0.07 micromol per g per min, Pcycling flux (3.1 to 5 x ; 0.07 to 0.11 (+/-0.03) versus 0.34+/-0.03 micromol per g per min, Pcycling (DeltaV(cyc(tot))) and neuronal TCA cycle flux (DeltaV(TCAn(tot))) between P10 and P30 were 0.23 to 0.27 and 0.47 micromol per g per min, respectively, similar to the approximately 1:2 relationship previously reported for adult cortex. For the individual neurons, increases in V(TCAn) and V(cyc) were similar in magnitude (glutamatergic neurons, 2.7 x versus 2.8 to 4.6 x ; GABAergic neurons, approximately 5 x versus approximately 7 x), although GABAergic flux changes were larger. The findings show that glutamate and GABA neurons undergo large and approximately proportional increases in neurotransmitter cycling and oxidative energy metabolism during this major postnatal growth spurt.

Acute orexigenic effect of agmatine involves interaction between central α2-adrenergic and GABAergic receptors.

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Taksande, Brijesh Gulabrao; Sharma, Omi; Aglawe, Manish Manohar; Kale, Mayur Bhimrao; Gawande, Dinesh Yugraj; Umekar, Milind Janraoji; Kotagale, Nandkishor Ramdas

2017-09-01

Agmatine and GABA have been abundantly expressed in brain nuclei involved in regulation of energy homeostasis and promoting stimulation of food intake in rodents. However, their mutual interaction, if any, in the elicitation of feeding behavior is largely remains unclear. The current study provides experimental evidence for the possible interaction of agmatine, adrenergic and GABAergic systems in stimulation of feeding in satiated rats. Satiated rats fitted with intracerebroventricular (i.c.v.) cannulae and were administered agmatine, alone or jointly with (a) GABA A receptor agonist, muscimol, diazepam or antagonist bicuculline and flumazenil, GABA A positive modulator, allopregnanolone or negative modulator of GABA A receptor, dehydroepiandrosterone (b) In view of the high affinity of agmatine for α 2 -adrenoceptors and the close association between α 2 -adrenoceptors and GABAergic system, the effect of their modulators on feeding elicited by agmatine/GABAergic agonists were also examined. I.c.v. administration of agmatine (40-80μg/rat) induces the significant orexigenic effect in satiated rats. The orexigenic effect of agmatine was potentiated by muscimol (25ng/rat, i.c.v.); diazepam (0.5mg/kg, i.p.); allopregnanolone (0.5mg/kg, s.c.) and blocked by bicuculline (1mg/kg, i.p.) and dehydroepiandrosterone (4mg/kg,s.c.). However, it remained unaffected in presence of flumazenil (25ng/rat, i.c.v.). The orexigenic effect of agmatine and GABAergic agonists was potentiated by a α 2 -adrenoceptors agonist, clonidine (10ng/rat, i.c.v.) and blocked by its antagonist, yohimbine (5μg/rat, i.c.v.). Yohimbine also blocked the hyperphagic effect elicited by ineffective dose combination of agmatine (5μg/rat, i.c.v.) with muscimol (25ng/rat, i.c.v.) or diazepam (0.5mg/kg, i.p.) or allopregnanolone (0.5mg/kg,s.c.). The results of the present study suggest that agmatine induced α 2 -adrenoceptors activation might facilitate GABAergic activity to stimulate food intake in

The genesis of cerebellar GABAergic neurons: fate potential and specification mechanisms

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Ketty eLeto

2012-02-01

Full Text Available The variety of neuronal phenotypes that populate the cerebellum derives from progenitors that proliferate in two germinal neuroepithelia: the ventricular zone generates GABAergic neurons, whereas the rhombic lip is the origin of glutamatergic types. Progenitors of the ventricular zone produce GABAergic projection neurons (Purkinje cells and nucleo-olivary neurons at the onset of cerebellar neurogenesis. Later on, however, these progenitors migrate into the prospective white matter, where they continue to divide up to postnatal development and generate different categories of inhibitory interneurons, according to precise spatio-temporal schedules. Projection neurons derive from discrete progenitor pools located in distinct microdomains of the ventricular zone, whereas interneurons originate from a single population of precursors, distinguished by the expression of the transcription factor Pax-2. Heterotopic/heterochronic transplantation experiments indicate that interneuron progenitors maintain full developmental potentialities up to the end of cerebellar development and acquire mature phenotypes under the influence of environmental cues present in the prospective white matter. Furthermore, the final fate choice occurs in postmitotic cells, rather than dividing progenitors. Extracerebellar cells grafted to the postnatal cerebellum are not responsive to local neurogenic cues and fail to adopt clear cerebellar identities. On the other hand, cerebellar cells grafted to extracerebellar regions retain typical phenotypes of cerebellar GABAergic interneurons, but acquire specific traits under the influence of local cues. These findings indicate that interneuron progenitors are multipotent and sensitive to spatio-temporally patterned environmental signals that regulate the genesis of different categories of interneurons, in precise quantities and at defined times and places.

Apolipoprotein E4 Causes Age- and Sex-Dependent Impairments of Hilar GABAergic Interneurons and Learning and Memory Deficits in Mice

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Leung, Laura; Andrews-Zwilling, Yaisa; Yoon, Seo Yeon; Jain, Sachi; Ring, Karen; Dai, Jessica; Wang, Max Mu; Tong, Leslie; Walker, David; Huang, Yadong

2012-01-01

Apolipoprotein (apo) E4 is the major genetic risk factor for Alzheimer's disease (AD). ApoE4 has sex-dependent effects, whereby the risk of developing AD is higher in apoE4-expressing females than males. However, the mechanism underlying the sex difference, in relation to apoE4, is unknown. Previous findings indicate that apoE4 causes age-dependent impairments of hilar GABAergic interneurons in female mice, leading to learning and memory deficits. Here, we investigate whether the detrimental effects of apoE4 on hilar GABAergic interneurons are sex-dependent using apoE knock-in (KI) mice across different ages. We found that in female apoE-KI mice, there was an age-dependent depletion of hilar GABAergic interneurons, whereby GAD67- or somatostatin-positive–but not NPY- or parvalbumin-positive–interneuron loss was exacerbated by apoE4. Loss of these neuronal populations was correlated with the severity of spatial learning deficits at 16 months of age in female apoE4-KI mice; however, this effect was not observed in female apoE3-KI mice. In contrast, we found an increase in the numbers of hilar GABAergic interneurons with advancing age in male apoE-KI mice, regardless of apoE genotype. Moreover, male apoE-KI mice showed a consistent ratio of hilar inhibitory GABAergic interneurons to excitatory mossy cells approximating 1.5 that is independent of apoE genotype and age, whereas female apoE-KI mice exhibited an age-dependent decrease in this ratio, which was exacerbated by apoE4. Interestingly, there are no apoE genotype effects on GABAergic interneurons in the CA1 and CA3 subregions of the hippocampus as well as the entorhinal and auditory cortexes. These findings suggest that the sex-dependent effects of apoE4 on developing AD is in part attributable to inherent sex-based differences in the numbers of hilar GABAergic interneurons, which is further modulated by apoE genotype. PMID:23300939

Local connections of layer 5 GABAergic interneurons to corticospinal neurons

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Yasuyo H Tanaka

2011-09-01

Full Text Available In the local circuit of the cerebral cortex, GABAergic inhibitory interneurons are considered to work in collaboration with excitatory neurons. Although many interneuron subgroups have been described in the cortex, local inhibitory connections of each interneuron subgroup are only partially understood with respect to the functional neuron groups that receive these inhibitory connections. In the present study, we morphologically examined local inhibitory inputs to corticospinal neurons (CSNs in motor areas using transgenic rats in which GABAergic neurons expressed fluorescent protein Venus. By analysis of biocytin-filled axons obtained with whole-cell recording/staining in cortical slices, we classified fast-spiking (FS neurons in layer (L 5 into two types, FS1 and FS2, by their high and low densities of axonal arborization, respectively. We then investigated the connections of FS1, FS2, somatostatin-immunopositive (SOM and other (non-FS/non-SOM interneurons to CSNs that were retrogradely labeled in a Golgi-like manner in motor areas. When close appositions between the axon boutons of the intracellularly labeled interneurons and the somata/dendrites of the retrogradely labeled CSNs were examined electron-microscopically, 74% of these appositions made symmetric synaptic contacts. The axon boutons of single FS1 neurons were 2–4-fold more frequent in appositions to the somata/dendrites of CSNs than those of FS2, SOM and non-FS/non-SOM neurons. Axosomatic appositions were most frequently formed with axon boutons of FS1 and FS2 neurons (approximately 30% and least frequently formed with those of SOM neurons (7%. In contrast, SOM neurons most extensively sent axon boutons to the apical dendrites of CSNs. These results might suggest that motor outputs are controlled differentially by the subgroups of L5 GABAergic interneurons in cortical motor areas. 

Neurofeedback Control of the Human GABAergic System Using Non-invasive Brain Stimulation.

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Koganemaru, Satoko; Mikami, Yusuke; Maezawa, Hitoshi; Ikeda, Satoshi; Ikoma, Katsunori; Mima, Tatsuya

2018-06-01

Neurofeedback has been a powerful method for self-regulating brain activities to elicit potential ability of human mind. GABA is a major inhibitory neurotransmitter in the central nervous system. Transcranial magnetic stimulation (TMS) is a tool that can evaluate the GABAergic system within the primary motor cortex (M1) using paired-pulse stimuli, short intracortical inhibition (SICI). Herein we investigated whether neurofeedback learning using SICI enabled us to control the GABAergic system within the M1 area. Forty-five healthy subjects were randomly divided into two groups: those receiving SICI neurofeedback learning or those receiving no neurofeedback (control) learning. During both learning periods, subjects made attempts to change the size of a circle, which was altered according to the degree of SICI in the SICI neurofeedback learning group, and which was altered independent of the degree of SICI in the control learning group. Results demonstrated that the SICI neurofeedback learning group showed a significant enhancement in SICI. Moreover, this group showed a significant reduction in choice reaction time compared to the control group. Our findings indicate that humans can intrinsically control the intracortical GABAergic system within M1 and can thus improve motor behaviors by SICI neurofeedback learning. SICI neurofeedback learning is a novel and promising approach to control our neural system and potentially represents a new therapy for patients with abnormal motor symptoms caused by CNS disorders. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Inheritance of congenital cataracts and microphthalmia in the Miniature Schnauzer.

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Gelatt, K N; Samuelson, D A; Bauer, J E; Das, N D; Wolf, E D; Barrie, K P; Andresen, T L

1983-06-01

Congenital cataracts and microphthalmia in the Miniature Schnauzer were inherited as an autosomal recessive trait. Eighteen matings of affected X affected Miniature Schnauzers resulted in 87 offspring with congenital cataracts and microphthalmia (49 males/38 females). Two matings of congenital cataractous and microphthalmic Miniature Schnauzers (2 females) X a normal Miniature Schnauzer (1 male) yielded 11 clinically normal Miniature Schnauzers (7 males/4 females). Eighteen matings of congenital cataractous and microphthalmic Miniature Schnauzers (6 males) X carrier Miniature Schnauzers (9 females) produced 81 offspring; 39 exhibited congenital cataracts and microphthalmia (20 males/19 females) and 42 had clinically normal eyes (17 males/25 females).

Unique functional properties of somatostatin-expressing GABAergic neurons in mouse barrel cortex.

NARCIS (Netherlands)

Gentet, L.J.; Kremer, Y.; Taniguchi, H.; Huang, Z.J.; Staiger, J.F.; Petersen, C.C.H.

2012-01-01

Neocortical GABAergic neurons have diverse molecular, structural and electrophysiological features, but the functional correlates of this diversity are largely unknown. We found unique membrane potential dynamics of somatostatin-expressing (SOM) neurons in layer 2/3 of the primary somatosensory

Noradrenergic and GABAergic systems in the medial hypothalamus are activated during hypoglycemia

NARCIS (Netherlands)

Beverly, JL; De Vries, MG; Bouman, SD; Arseneau, LM

Noradrenergic and GABAergic systems in the medial hypothalamus influence plasma glucose and may be activated during glucoprivation. Microdialysis probes were placed into the ventromedial nucleus (VMH), lateral hypothalamus (LHA), and paraventricular nucleus (PVH) of male Sprague-Dawley rats to

Comprehensive association analysis of 27 genes from the GABAergic system in Japanese individuals affected with schizophrenia.

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Balan, Shabeesh; Yamada, Kazuo; Iwayama, Yoshimi; Hashimoto, Takanori; Toyota, Tomoko; Shimamoto, Chie; Maekawa, Motoko; Takagai, Shu; Wakuda, Tomoyasu; Kameno, Yosuke; Kurita, Daisuke; Yamada, Kohei; Kikuchi, Mitsuru; Hashimoto, Tasuku; Kanahara, Nobuhisa; Yoshikawa, Takeo

2017-07-01

Involvement of the gamma-aminobutyric acid (GABA)-ergic system in schizophrenia pathogenesis through disrupted neurodevelopment has been highlighted in numerous studies. However, the function of common genetic variants of this system in determining schizophrenia risk is unknown. We therefore tested the association of 375 tagged SNPs in genes derived from the GABAergic system, such as GABA A receptor subunit genes, and GABA related genes (glutamate decarboxylase genes, GABAergic-marker gene, genes involved in GABA receptor trafficking and scaffolding) in Japanese schizophrenia case-control samples (n=2926; 1415 cases and 1511 controls). We observed nominal association of SNPs in nine GABA A receptor subunit genes and the GPHN gene with schizophrenia, although none survived correction for study-wide multiple testing. Two SNPs located in the GABRA1 gene, rs4263535 (P allele =0.002; uncorrected) and rs1157122 (P allele =0.006; uncorrected) showed top hits, followed by rs723432 (P allele =0.007; uncorrected) in the GPHN gene. All three were significantly associated with schizophrenia and survived gene-wide multiple testing. Haplotypes containing associated variants in GABRA1 but not GPHN were significantly associated with schizophrenia. To conclude, we provided substantiating genetic evidence for the involvement of the GABAergic system in schizophrenia susceptibility. These results warrant further investigations to replicate the association of GABRA1 and GPHN with schizophrenia and to discern the precise mechanisms of disease pathophysiology. Copyright © 2017 Elsevier B.V. All rights reserved.

Serum C-reactive protein concentrations in healthy Miniature Schnauzer dogs.

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Wong, Valerie M; Kidney, Beverly A; Snead, Elisabeth C R; Myers, Sherry L; Jackson, Marion L

2011-09-01

C-reactive protein (CRP) is a sensitive marker for inflammation in people and dogs. In people, an association between CRP concentration and atherosclerosis has been reported. Atherosclerosis is rare in dogs, but the Miniature Schnauzer breed may be at increased risk for developing this vascular disease. It is not known if CRP concentrations in Miniature Schnauzer dogs differ from those in other dog breeds. Our objectives were to validate an automated human CRP assay for measuring CRP in dogs and compare CRP concentrations in healthy Miniature Schnauzer dogs with those in non-Miniature Schnauzer breeds. Sera from 37 non-Miniature Schnauzer dogs with inflammatory disease were pooled and used to validate a human CRP immunoturbidimetric assay for measuring canine CRP. Blood was collected from 20 healthy Miniature Schnauzer dogs and 41 healthy dogs of other breeds. Median serum CRP concentration of healthy Miniature Schnauzer dogs was compared with that of healthy non-Miniature Schnauzer dogs. The human CRP assay measured CRP reliably with linearity between 0 and 20 mg/L. CRP concentration for healthy Miniature Schnauzer dogs (median 4.0 mg/L, minimum-maximum 0-18.2 mg/L) was significantly higher than for the healthy non-Miniature Schnauzer dogs (median 0.1 mg/L, minimum-maximum 0-10.7 mg/L); 17 of the 20 Miniature Schnauzer dogs had values that overlapped with those of the non-Miniature Schnauzer dogs. Median CRP concentration of Miniature Schnauzer dogs was slightly higher than that of other breeds of dogs. A relationship between higher CRP concentration in Miniature Schnauzer dogs and idiopathic hyperlipidemia, pancreatitis, and possible increased risk for atherosclerosis remains to be determined. ©2011 American Society for Veterinary Clinical Pathology.

Glucose sensing by GABAergic neurons in the mouse nucleus tractus solitarii

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Boychuk, Carie R.; Gyarmati, Peter; Xu, Hong

2015-01-01

Changes in blood glucose concentration alter autonomic function in a manner consistent with altered neural activity in brain regions controlling digestive processes, including neurons in the brain stem nucleus tractus solitarii (NTS), which process viscerosensory information. With whole cell or on-cell patch-clamp recordings, responses to elevating glucose concentration from 2.5 to 15 mM were assessed in identified GABAergic NTS neurons in slices from transgenic mice that express EGFP in a subset of GABA neurons. Single-cell real-time RT-PCR was also performed to detect glutamic acid decarboxylase (GAD67) in recorded neurons. In most identified GABA neurons (73%), elevating glucose concentration from 2.5 to 15 mM resulted in either increased (40%) or decreased (33%) neuronal excitability, reflected by altered membrane potential and/or action potential firing. Effects on membrane potential were maintained when action potentials or fast synaptic inputs were blocked, suggesting direct glucose sensing by GABA neurons. Glucose-inhibited GABA neurons were found predominantly in the lateral NTS, whereas glucose-excited cells were mainly in the medial NTS, suggesting regional segregation of responses. Responses were prevented in the presence of glucosamine, a glucokinase (GCK) inhibitor. Depolarizing responses were prevented when KATP channel activity was blocked with tolbutamide. Whereas effects on synaptic input to identified GABAergic neurons were variable in GABA neurons, elevating glucose increased glutamate release subsequent to stimulation of tractus solitarius in unlabeled, unidentified neurons. These results indicate that GABAergic NTS neurons act as GCK-dependent glucose sensors in the vagal complex, providing a means of modulating central autonomic signals when glucose is elevated. PMID:26084907

Piriform cortical glutamatergic and GABAergic neurons express coordinated plasticity for whisker-induced odor recall.

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Liu, Yahui; Gao, Zilong; Chen, Changfeng; Wen, Bo; Huang, Li; Ge, Rongjing; Zhao, Shidi; Fan, Ruichen; Feng, Jing; Lu, Wei; Wang, Liping; Wang, Jin-Hui

2017-11-10

Neural plasticity occurs in learning and memory. Coordinated plasticity at glutamatergic and GABAergic neurons during memory formation remains elusive, which we investigate in a mouse model of associative learning by cellular imaging and electrophysiology. Paired odor and whisker stimulations lead to whisker-induced olfaction response. In mice that express this cross-modal memory, the neurons in the piriform cortex are recruited to encode newly acquired whisker signal alongside innate odor signal, and their response patterns to these associated signals are different. There are emerged synaptic innervations from barrel cortical neurons to piriform cortical neurons from these mice. These results indicate the recruitment of associative memory cells in the piriform cortex after associative memory. In terms of the structural and functional plasticity at these associative memory cells in the piriform cortex, glutamatergic neurons and synapses are upregulated, GABAergic neurons and synapses are downregulated as well as their mutual innervations are refined in the coordinated manner. Therefore, the associated activations of sensory cortices triggered by their input signals induce the formation of their mutual synapse innervations, the recruitment of associative memory cells and the coordinated plasticity between the GABAergic and glutamatergic neurons, which work for associative memory cells to encode cross-modal associated signals in their integration, associative storage and distinguishable retrieval.

Accelerated Intoxication of GABAergic Synapses by Botulinum Neurotoxin A Disinhibits Stem Cell-Derived Neuron Networks Prior to Network Silencing

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2015-04-23

administered BoNT can lead to central nervous system intoxication is currently being debated. Recent findings in vitro and in vivo suggest that BoNT...Literature 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Accelerated intoxication of GABAergic synapses by botulinum neurotoxin A disinhibits 5a...April 2015 Published: 23 April 2015 Citation: Beske PH, Scheeler SM, AdlerM and McNutt PM (2015) Accelerated intoxication of GABAergic synapses by

Reestablishment of radiographic kidney size in Miniature Schnauzer dogs.

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Sohn, Jungmin; Yun, Sookyung; Lee, Jeosoon; Chang, Dongwoo; Choi, Mincheol; Yoon, Junghee

2017-01-10

Kidney size may be altered in renal diseases, and the detection of kidney size alteration has diagnostic and prognostic values. We hypothesized that radiographic kidney size, the kidney length to the second lumbar vertebra (L2) length ratio, in normal Miniature Schnauzer dogs may be overestimated due to their shorter vertebral length. This study was conducted to evaluate radiographic and ultrasonographic kidney size and L2 length in clinically normal Miniature Schnauzers and other dog breeds to evaluate the effect of vertebral length on radiographic kidney size and to reestablish radiographic kidney size in normal Miniature Schnauzers. Abdominal radiographs and ultrasonograms from 49 Miniature Schnauzers and 54 other breeds without clinical evidence of renal disease and lumbar vertebral abnormality were retrospectively evaluated. Radiographic kidney size, in the Miniature Schnauzer (3.31 ± 0.26) was significantly larger than that in other breeds (2.94 ± 0.27). Relative L2 length, the L2 length to width ratio, in the Miniature Schnauzer (1.11 ± 0.06) was significantly shorter than that in other breeds (1.21 ± 0.09). However, ultrasonographic kidney sizes, kidney length to aorta diameter ratios, were within or very close to normal range both in the Miniature Schnauzer (6.75 ± 0.67) and other breeds (7.16 ± 1.01). Thus, Miniature Schnauzer dogs have breed-specific short vertebrae and consequently a larger radiographic kidney size, which was greater than standard reference in normal adult dogs. Care should be taken when evaluating radiographic kidney size in Miniature Schnauzers to prevent falsely diagnosed renomegaly.

Thyroid hormone-dependent development of early cortical networks: Temporal specificity and the contribution of trkB and mTOR pathways

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Sören eWesterholz

2013-08-01

Full Text Available Early in neocortical network development, triiodothyronine (T3 promotes GABAergic neurons’ population increase, their somatic growth and the formation of GABAergic synapses. In the presence of T3, GABAergic interneurons form longer axons and conspicuous axonal arborizations, with an increased number of putative synaptic boutons. Here we show that the increased GABAergic axonal growth is positively correlated with the proximity to non-GABAergic neurons. A differential innervation emerges from a T3-dependent decrease of axonal length in fields with low density of neuronal cell bodies, combined with an increased bouton formation in fields with high density of neuronal somata. T3 addition to deprived networks after the first two weeks of development did not rescue deficits in the GABAergic synaptic bouton distribution, or in the frequency and duration of spontaneous bursts. During the critical two-week-period, GABAergic signaling is depolarizing as revealed by calcium imaging experiments. Interestingly, T3 enhanced the expression of the potassium-chloride cotransporter 2 (KCC2, and accelerated the developmental shift from depolarizing to hyperpolarizing GABAergic signaling in non-GABAergic neurons.The T3-related increase of spontaneous network activity was remarkably reduced after blockade of either tropomyosin-receptor kinase B (trkB or mammalian target of rapamycin (mTOR pathways. T3-dependent increase in GABAergic neurons’ soma size was mediated mainly by mTOR signaling. Conversely, the T3-dependent selective increase of GABAergic boutons near non-GABAergic cell bodies is mediated by trkB signaling only. Both trkB and mTOR signaling mediate T3-dependent reduction of the GABAergic axon extension. The circuitry context is relevant for the interaction between T3 and trkB signaling, but not for the interactions between T3 and mTOR signaling.

Small Scaffolds, Big Potential: Developing Miniature Proteins as Therapeutic Agents.

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Holub, Justin M

2017-09-01

Preclinical Research Miniature proteins are a class of oligopeptide characterized by their short sequence lengths and ability to adopt well-folded, three-dimensional structures. Because of their biomimetic nature and synthetic tractability, miniature proteins have been used to study a range of biochemical processes including fast protein folding, signal transduction, catalysis and molecular transport. Recently, miniature proteins have been gaining traction as potential therapeutic agents because their small size and ability to fold into defined tertiary structures facilitates their development as protein-based drugs. This research overview discusses emerging developments involving the use of miniature proteins as scaffolds to design novel therapeutics for the treatment and study of human disease. Specifically, this review will explore strategies to: (i) stabilize miniature protein tertiary structure; (ii) optimize biomolecular recognition by grafting functional epitopes onto miniature protein scaffolds; and (iii) enhance cytosolic delivery of miniature proteins through the use of cationic motifs that facilitate endosomal escape. These objectives are discussed not only to address challenges in developing effective miniature protein-based drugs, but also to highlight the tremendous potential miniature proteins hold for combating and understanding human disease. Drug Dev Res 78 : 268-282, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Hypoxia preferentially destroys GABAergic neurons in developing rat neocortex explants in culture

NARCIS (Netherlands)

Romijn, H. J.; Ruijter, J. M.; Wolters, P. S.

1988-01-01

The hypothesis that hypoxic ischemia before or during the human birth process preferentially destroys GABAergic nerve cells, particularly in the neocortex, was tested in a tissue culture model system. To that end, rat neocortex explants dissected from 6-day-old rat pups and cultured to a

Miniaturized isothermal nucleic acid amplification, a review.

Science.gov (United States)

Asiello, Peter J; Baeumner, Antje J

2011-04-21

Micro-Total Analysis Systems (µTAS) for use in on-site rapid detection of DNA or RNA are increasingly being developed. Here, amplification of the target sequence is key to increasing sensitivity, enabling single-cell and few-copy nucleic acid detection. The several advantages to miniaturizing amplification reactions and coupling them with sample preparation and detection on the same chip are well known and include fewer manual steps, preventing contamination, and significantly reducing the volume of expensive reagents. To-date, the majority of miniaturized systems for nucleic acid analysis have used the polymerase chain reaction (PCR) for amplification and those systems are covered in previous reviews. This review provides a thorough overview of miniaturized analysis systems using alternatives to PCR, specifically isothermal amplification reactions. With no need for thermal cycling, isothermal microsystems can be designed to be simple and low-energy consuming and therefore may outperform PCR in portable, battery-operated detection systems in the future. The main isothermal methods as miniaturized systems reviewed here include nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP), helicase-dependent amplification (HDA), rolling circle amplification (RCA), and strand displacement amplification (SDA). Also, important design criteria for the miniaturized devices are discussed. Finally, the potential of miniaturization of some new isothermal methods such as the exponential amplification reaction (EXPAR), isothermal and chimeric primer-initiated amplification of nucleic acids (ICANs), signal-mediated amplification of RNA technology (SMART) and others is presented.

Discreet charm of the GABAergic bourgeoisie: superconnected cells conduct developmental symphonies.

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Case, Marianne; Soltesz, Ivan

2009-12-24

In an exciting study in the December 4(th) issue of Science, Bonifazi and colleagues demonstrated the existence and importance of exceedingly rare but unusually richly connected cells in the developing hippocampus. Manipulating the activity of single GABAergic hub cells modulated network activity patterns, demonstrating their importance for coordinating synchronous activity. 2009 Elsevier Inc. All rights reserved.

Miniaturization in Biocatalysis

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Pedro Fernandes

2010-03-01

Full Text Available The use of biocatalysts for the production of both consumer goods and building blocks for chemical synthesis is consistently gaining relevance. A significant contribution for recent advances towards further implementation of enzymes and whole cells is related to the developments in miniature reactor technology and insights into flow behavior. Due to the high level of parallelization and reduced requirements of chemicals, intensive screening of biocatalysts and process variables has become more feasible and reproducibility of the bioconversion processes has been substantially improved. The present work aims to provide an overview of the applications of miniaturized reactors in bioconversion processes, considering multi-well plates and microfluidic devices, update information on the engineering characterization of the hardware used, and present perspective developments in this area of research.

Medial septal GABAergic projection neurons promote object exploration behavior and type 2 theta rhythm

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Gangadharan, Gireesh; Shin, Jonghan; Kim, Seong-Wook; Kim, Angela; Paydar, Afshin; Kim, Duk-Soo; Miyazaki, Taisuke; Watanabe, Masahiko; Yanagawa, Yuchio; Kim, Jinhyun; Kim, Yeon-Soo; Kim, Daesoo; Shin, Hee-Sup

2016-01-01

Exploratory drive is one of the most fundamental emotions, of all organisms, that are evoked by novelty stimulation. Exploratory behavior plays a fundamental role in motivation, learning, and well-being of organisms. Diverse exploratory behaviors have been described, although their heterogeneity is not certain because of the lack of solid experimental evidence for their distinction. Here we present results demonstrating that different neural mechanisms underlie different exploratory behaviors. Localized Cav3.1 knockdown in the medial septum (MS) selectively enhanced object exploration, whereas the null mutant (KO) mice showed enhanced-object exploration as well as open-field exploration. In MS knockdown mice, only type 2 hippocampal theta rhythm was enhanced, whereas both type 1 and type 2 theta rhythm were enhanced in KO mice. This selective effect was accompanied by markedly increased excitability of septo-hippocampal GABAergic projection neurons in the MS lacking T-type Ca2+ channels. Furthermore, optogenetic activation of the septo-hippocampal GABAergic pathway in WT mice also selectively enhanced object exploration behavior and type 2 theta rhythm, whereas inhibition of the same pathway decreased the behavior and the rhythm. These findings define object exploration distinguished from open-field exploration and reveal a critical role of T-type Ca2+ channels in the medial septal GABAergic projection neurons in this behavior. PMID:27208094

Liquid storage of miniature boar semen.

Science.gov (United States)

Shimatsu, Yoshiki; Uchida, Masaki; Niki, Rikio; Imai, Hiroshi

2002-04-01

The effects of liquid storage at 15 degrees C on the fertilizing ability of miniature pig semen were investigated. Characterization of ejaculated semen from 3 miniature boars was carried out. Semen volume and pH were similar among these boars. In one of the boars, sperm motility was slightly low, and sperm concentration and total number of sperm were significantly lower than in the others (P semen was substituted with various extenders (Kiev, Androhep, BTS and Modena) by centrifugation and semen was stored for 7 days at 15 degrees C. Sperm motility was estimated daily at 37 degrees C. For complete substitution of seminal plasma, Modena was significantly more efficient than the other extenders (P Semen from each of the 3 miniature boars that had been stored for 5 to 7 days at 15 degrees C in Modena was used for artificial insemination of 15 miniature sows. The farrowing rates were 100, 100 and 60%, and litter sizes were 6.4 +/- 1.5, 5.8 +/- 0.8 and 5.0 +/- 1.0 for each boar semen, respectively. The boar that sired the smallest farrowing rate was the same one that showed lower seminal quality with respect to sperm motility, sperm concentration and total number of sperm. These results suggest that miniature boar semen can be stored for at least 5 days at 15 degrees C by the substitution of seminal plasma with Modena extender.

The interaction of central nitrergic and GABAergic systems on food intake in neonatal layer-type chicks.

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Mokhtarpouriani, Kasra; Zendehdel, Morteza; Jonaidi, Hossein; Babapour, Vahab; Shayan, Parviz

2016-05-01

Most physiological behaviors such as food intake are controlled by the hypothalamus and its nuclei. It has been demonstrated that injection of the paraventricular nucleus of the hypothalamus with nitric oxide (NO) donors elicited changes in the concentration of some amino acids, including GABA. Also, central nitrergic and GABAergic systems are known to provide inputs to the paraventricular nucleus and are involved in food intake control. Therefore, the present study examines the probable interaction of central nitrergic and GABAergic systems on food intake in neonatal layer-type chicks. The results of this study showed that intracerebroventricular (ICV) injection of L-arginine (400 and 800 nmol), as a NO donor, significantly decreased food intake (P 0.05). Also, the hypophagic effect of L-arginine (800 nmol) was significantly amplified in ICV co-injection of picrotoxin (0.5 µg), a GABAA antagonist, or CGP54626 (21 ng), a GABAB antagonist, with L-arginine (800 nmol) (P < 0.001). These results probably suggest an interaction of central nitrergic and GABAergic systems on food intake in neonatal layer-type chicks and GABAA receptors play a major role in this interaction.

Advances in miniature spectrometer and sensor development

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Malinen, Jouko; Rissanen, Anna; Saari, Heikki; Karioja, Pentti; Karppinen, Mikko; Aalto, Timo; Tukkiniemi, Kari

2014-05-01

Miniaturization and cost reduction of spectrometer and sensor technologies has great potential to open up new applications areas and business opportunities for analytical technology in hand held, mobile and on-line applications. Advances in microfabrication have resulted in high-performance MEMS and MOEMS devices for spectrometer applications. Many other enabling technologies are useful for miniature analytical solutions, such as silicon photonics, nanoimprint lithography (NIL), system-on-chip, system-on-package techniques for integration of electronics and photonics, 3D printing, powerful embedded computing platforms, networked solutions as well as advances in chemometrics modeling. This paper will summarize recent work on spectrometer and sensor miniaturization at VTT Technical Research Centre of Finland. Fabry-Perot interferometer (FPI) tunable filter technology has been developed in two technical versions: Piezoactuated FPIs have been applied in miniature hyperspectral imaging needs in light weight UAV and nanosatellite applications, chemical imaging as well as medical applications. Microfabricated MOEMS FPIs have been developed as cost-effective sensor platforms for visible, NIR and IR applications. Further examples of sensor miniaturization will be discussed, including system-on-package sensor head for mid-IR gas analyzer, roll-to-roll printed Surface Enhanced Raman Scattering (SERS) technology as well as UV imprinted waveguide sensor for formaldehyde detection.

Abnormal GABAergic function and negative affect in schizophrenia.

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Taylor, Stephan F; Demeter, Elise; Phan, K Luan; Tso, Ivy F; Welsh, Robert C

2014-03-01

Deficits in the γ-aminobutyric acid (GABA) system have been reported in postmortem studies of schizophrenia, and therapeutic interventions in schizophrenia often involve potentiation of GABA receptors (GABAR) to augment antipsychotic therapy and treat negative affect such as anxiety. To map GABAergic mechanisms associated with processing affect, we used a benzodiazepine challenge while subjects viewed salient visual stimuli. Fourteen stable, medicated schizophrenia/schizoaffective patients and 13 healthy comparison subjects underwent functional magnetic resonance imaging using the blood oxygenation level-dependent (BOLD) technique while they viewed salient emotional images. Subjects received intravenous lorazepam (LRZ; 0.01 mg/kg) or saline in a single-blinded, cross-over design (two sessions separated by 1-3 weeks). A predicted group by drug interaction was noted in the dorsal medial prefrontal cortex (dmPFC) as well as right superior frontal gyrus and left and right occipital regions, such that psychosis patients showed an increased BOLD signal to LRZ challenge, rather than the decreased signal exhibited by the comparison group. A main effect of reduced BOLD signal in bilateral occipital areas was noted across groups. Consistent with the role of the dmPFC in processing emotion, state negative affect positively correlated with the response to the LRZ challenge in the dmPFC for the patients and comparison subjects. The altered response to LRZ challenge is consistent with altered inhibition predicted by postmortem findings of altered GABAR in schizophrenia. These results also suggest that negative affect in schizophrenia/schizoaffective disorder is associated-directly or indirectly-with GABAergic function on a continuum with normal behavior.

Abnormal GABAergic function and face processing in schizophrenia: A pharmacologic-fMRI study.

Science.gov (United States)

Tso, Ivy F; Fang, Yu; Phan, K Luan; Welsh, Robert C; Taylor, Stephan F

2015-10-01

The involvement of the gamma-aminobutyric acid (GABA) system in schizophrenia is suggested by postmortem studies and the common use of GABA receptor-potentiating agents in treatment. In a recent study, we used a benzodiazepine challenge to demonstrate abnormal GABAergic function during processing of negative visual stimuli in schizophrenia. This study extended this investigation by mapping GABAergic mechanisms associated with face processing and social appraisal in schizophrenia using a benzodiazepine challenge. Fourteen stable, medicated schizophrenia/schizoaffective patients (SZ) and 13 healthy controls (HC) underwent functional MRI using the blood oxygenation level-dependent (BOLD) technique while they performed the Socio-emotional Preference Task (SePT) on emotional face stimuli ("Do you like this face?"). Participants received single-blinded intravenous saline and lorazepam (LRZ) in two separate sessions separated by 1-3weeks. Both SZ and HC recruited medial prefrontal cortex/anterior cingulate during the SePT, relative to gender identification. A significant drug by group interaction was observed in the medial occipital cortex, such that SZ showed increased BOLD signal to LRZ challenge, while HC showed an expected decrease of signal; the interaction did not vary by task. The altered BOLD response to LRZ challenge in SZ was significantly correlated with increased negative affect across multiple measures. The altered response to LRZ challenge suggests that abnormal face processing and negative affect in SZ are associated with altered GABAergic function in the visual cortex, underscoring the role of impaired visual processing in socio-emotional deficits in schizophrenia. Copyright © 2015 Elsevier B.V. All rights reserved.

Miniaturized GPS/MEMS IMU integrated board

Science.gov (United States)

Lin, Ching-Fang (Inventor)

2012-01-01

This invention documents the efforts on the research and development of a miniaturized GPS/MEMS IMU integrated navigation system. A miniaturized GPS/MEMS IMU integrated navigation system is presented; Laser Dynamic Range Imager (LDRI) based alignment algorithm for space applications is discussed. Two navigation cameras are also included to measure the range and range rate which can be integrated into the GPS/MEMS IMU system to enhance the navigation solution.

Miniaturizing RFID for magnamosis.

Science.gov (United States)

Jiang, Hao; Chen, Shijie; Kish, Shad; Loh, Lokkee; Zhang, Junmin; Zhang, Xiaorong; Kwiat, Dillon; Harrison, Michael; Roy, Shuvo

2014-01-01

Anastomosis is a common surgical procedure using staples or sutures in an open or laparoscopic surgery. A more effective and much less invasive alternative is to apply the mechanical pressure on the tissue over a few days [1]. Since the pressure is produced by the attractive force between two permanent magnets, the procedure is called magnamosis[1]. To ensure the two magnets are perfectly aligned during the surgery, a miniaturized batteryless Radio Frequency IDentification (RFID) tag is developed to wirelessly telemeter the status of a pressure sensitive mechanical switch. Using the multi-layer circular spiral coil design, the diameter of the RFID tag is shrunk to 10, 15, 19 and 27 mm to support the magnamosis for children as well as adults. With the impedance matching network, the operating distance of these four RFID tags are longer than 10 cm in a 20 × 22 cm(2) area, even when the tag's normal direction is 45° off the antenna's normal direction. Measurement results also indicate that there is no noticeable degradation on the operating distance when the tag is immersed in saline or placed next to the rare-earth magnet. The miniaturized RFID tag presented in this paper is able to support the magnamosis and other medical applications that require the miniaturized RFID tag.

A new role for GABAergic transmission in the control of male rat sexual behavior expression.

Science.gov (United States)

Rodríguez-Manzo, Gabriela; Canseco-Alba, Ana

2017-03-01

GABAergic transmission in the ventral tegmental area (VTA) exerts a tonic inhibitory influence on mesolimbic dopaminergic neurons' activity. Blockade of VTA GABA A receptors increases dopamine release in the nucleus accumbens (NAcc). Increases in NAcc dopamine levels typically accompany sexual behavior display. Copulation to satiety is characterized by the instatement of a long lasting (72h) sexual behavior inhibition and the mesolimbic system appears to be involved in this phenomenon. GABAergic transmission in the VTA might play a role in the maintenance of this long lasting sexual inhibitory state. To test this hypothesis, in the present work we investigated the effect of GABA A receptor blockade in sexually exhausted males 24h after copulation to satiety, once the sexual inhibitory state is established, and compared it with its effect in sexually experienced rats. Results showed that low doses of systemically administered bicuculline induced sexual behavior expression in sexually exhausted rats, but lacked an effect on copulation of sexually experienced animals. Intra-VTA bilateral infusion of bicuculline did not modify sexual behavior of sexually experienced rats, but induced sexual behavior expression in all the sexually exhausted males. Hence, GABA plays a role in the control of sexual behavior expression at the VTA. The role played by GABAergic transmission in male sexual behavior expression of animals with distinct sexual behavior conditions is discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Behavior-Dependent Activity and Synaptic Organization of Septo-hippocampal GABAergic Neurons Selectively Targeting the Hippocampal CA3 Area.

Science.gov (United States)

Joshi, Abhilasha; Salib, Minas; Viney, Tim James; Dupret, David; Somogyi, Peter

2017-12-20

Rhythmic medial septal (MS) GABAergic input coordinates cortical theta oscillations. However, the rules of innervation of cortical cells and regions by diverse septal neurons are unknown. We report a specialized population of septal GABAergic neurons, the Teevra cells, selectively innervating the hippocampal CA3 area bypassing CA1, CA2, and the dentate gyrus. Parvalbumin-immunopositive Teevra cells show the highest rhythmicity among MS neurons and fire with short burst duration (median, 38 ms) preferentially at the trough of both CA1 theta and slow irregular oscillations, coincident with highest hippocampal excitability. Teevra cells synaptically target GABAergic axo-axonic and some CCK interneurons in restricted septo-temporal CA3 segments. The rhythmicity of their firing decreases from septal to temporal termination of individual axons. We hypothesize that Teevra neurons coordinate oscillatory activity across the septo-temporal axis, phasing the firing of specific CA3 interneurons, thereby contributing to the selection of pyramidal cell assemblies at the theta trough via disinhibition. VIDEO ABSTRACT. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Neurokinin-1 receptor activation in globus pallidus

Directory of Open Access Journals (Sweden)

Lei Chen

2009-10-01

Full Text Available The undecapeptide substance P has been demonstrated to modulate neuronal activity in a number of brain regions by acting on neurokinin-1 receptors. Anatomical studies revealed a moderate level of neurokinin-1 receptor in rat globus pallidus. To determine the electrophysiological effects of neurokinin-1 receptor activation in globus pallidus, whole-cell patch-clamp recordings were performed in the present study. Under current-clamp recordings, neurokinin-1 receptor agonist, [Sar9, Met(O211] substance P (SM-SP at 1 μM, depolarized globus pallidus neurons and increased their firing rate. Consistently, SM-SP induced an inward current under voltage-clamp recording. The depolarization evoked by SM-SP persisted in the presence of tetrodotoxin, glutamate and GABA receptor antagonists, indicating its direct postsynaptic effects. The neurokinin-1 receptor antagonist, SR140333B, could block SM-SP-induced depolarization. Further experiments showed that suppression of potassium conductance was the predominant ionic mechanism of SM-SP-induced depolarization. To determine if neurokinin-1 receptor activation exerts any effects on GABAergic and glutamatergic neurotransmission, the action of SM-SP on synaptic currents was studied. SM-SP significantly increased the frequency of spontaneous inhibitory postsynaptic currents, but only induced a transient increase in the frequency of miniature inhibitory postsynaptic currents. No change was observed in both spontaneous and miniature excitatory postsynaptic currents. Based on the direct excitatory effects of SM-SP on pallidal neurons, we hypothesize that neurokinin-1 receptor activation in globus pallidus may be involved in the beneficial effect of substance P in Parkinson’s disease.

Specification of spatial identities of cerebellar neuron progenitors by ptf1a and atoh1 for proper production of GABAergic and glutamatergic neurons.

Science.gov (United States)

Yamada, Mayumi; Seto, Yusuke; Taya, Shinichiro; Owa, Tomoo; Inoue, Yukiko U; Inoue, Takayoshi; Kawaguchi, Yoshiya; Nabeshima, Yo-Ichi; Hoshino, Mikio

2014-04-02

In the cerebellum, the bHLH transcription factors Ptf1a and Atoh1 are expressed in distinct neuroepithelial regions, the ventricular zone (VZ) and the rhombic lip (RL), and are required for producing GABAergic and glutamatergic neurons, respectively. However, it is unclear whether Ptf1a or Atoh1 is sufficient for specifying GABAergic or glutamatergic neuronal fates. To test this, we generated two novel knock-in mouse lines, Ptf1a(Atoh1) and Atoh1(Ptf1a), that are designed to express Atoh1 and Ptf1a ectopically in the VZ and RL, respectively. In Ptf1a(Atoh1) embryos, ectopically Atoh1-expressing VZ cells produced glutamatergic neurons, including granule cells and deep cerebellar nuclei neurons. Correspondingly, in Atoh1(Ptf1a) animals, ectopically Ptf1a-expressing RL cells produced GABAergic populations, such as Purkinje cells and GABAergic interneurons. Consistent results were also obtained from in utero electroporation of Ptf1a or Atoh1 into embryonic cerebella, suggesting that Ptf1a and Atoh1 are essential and sufficient for GABAergic versus glutamatergic specification in the neuroepithelium. Furthermore, birthdating analyses with BrdU in the knock-in mice or with electroporation studies showed that ectopically produced fate-changed neuronal types were generated at temporal schedules closely simulating those of the wild-type RL and VZ, suggesting that the VZ and RL share common temporal information. Observations of knock-in brains as well as electroporated brains revealed that Ptf1a and Atoh1 mutually negatively regulate their expression, probably contributing to formation of non-overlapping neuroepithelial domains. These findings suggest that Ptf1a and Atoh1 specify spatial identities of cerebellar neuron progenitors in the neuroepithelium, leading to appropriate production of GABAergic and glutamatergic neurons, respectively.

Miniature x-ray source

Science.gov (United States)

Trebes, James E.; Bell, Perry M.; Robinson, Ronald B.

2000-01-01

A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

Miniature mass analyzer

CERN Document Server

Cuna, C; Lupsa, N; Cuna, S; Tuzson, B

2003-01-01

The paper presents the concept of different mass analyzers that were specifically designed as small dimension instruments able to detect with great sensitivity and accuracy the main environmental pollutants. The mass spectrometers are very suited instrument for chemical and isotopic analysis, needed in environmental surveillance. Usually, this is done by sampling the soil, air or water followed by laboratory analysis. To avoid drawbacks caused by sample alteration during the sampling process and transport, the 'in situ' analysis is preferred. Theoretically, any type of mass analyzer can be miniaturized, but some are more appropriate than others. Quadrupole mass filter and trap, magnetic sector, time-of-flight and ion cyclotron mass analyzers can be successfully shrunk, for each of them some performances being sacrificed but we must know which parameters are necessary to be kept unchanged. To satisfy the miniaturization criteria of the analyzer, it is necessary to use asymmetrical geometries, with ion beam obl...

Impairment of GABA transporter GAT-1 terminates cortical recurrent network activity via enhanced phasic inhibition

Directory of Open Access Journals (Sweden)

Daniel Simon Razik

2013-09-01

Full Text Available In the central nervous system, GABA transporters (GATs very efficiently clear synaptically released GABA from the extracellular space, and thus exert a tight control on GABAergic inhibition. In neocortex, GABAergic inhibition is heavily recruited during recurrent phases of spontaneous action potential activity which alternate with neuronally quiet periods. Therefore, such activity should be quite sensitive to minute alterations of GAT function. Here, we explored the effects of a gradual impairment of GAT-1 and GAT-2/3 on spontaneous recurrent network activity – termed network bursts and silent periods – in organotypic slice cultures of rat neocortex. The GAT-1 specific antagonist NO-711 depressed activity already at nanomolar concentrations (IC50 for depression of spontaneous multiunit firing rate of 42 nM, reaching a level of 80% at 500-1000 nM. By contrast, the GAT-2/3 preferring antagonist SNAP-5114 had weaker and less consistent effects. Several lines of evidence pointed towards an enhancement of phasic GABAergic inhibition as the dominant activity-depressing mechanism: network bursts were drastically shortened, phasic GABAergic currents decayed slower, and neuronal excitability during ongoing activity was diminished. In silent periods, NO-711 had little effect on neuronal excitability or membrane resistance, quite in contrast to the effects of muscimol, a GABA mimetic which activates GABAA receptors tonically. Our results suggest that an enhancement of phasic GABAergic inhibition efficiently curtails cortical recurrent activity and may mediate antiepileptic effects of therapeutically relevant concentrations of GAT-1 antagonists.

Novel lipoprotein density profiling in healthy dogs of various breeds, healthy miniature schnauzers, and miniature schnauzers with hyperlipidemia

Science.gov (United States)

2013-01-01

Background Despite the importance of abnormalities in lipoprotein metabolism in clinical canine medicine, the fact that most previously used methods for lipoprotein profiling are rather laborious and time-consuming has been a major obstacle to the wide clinical application and use of lipoprotein profiling in this species. The aim of the present study was to assess the feasibility of a continuous lipoprotein density profile (CLPDP) generated within a bismuth sodium ethylenediaminetetraacetic acid (NaBiEDTA) density gradient to characterize and compare the lipoprotein profiles of healthy dogs of various breeds, healthy Miniature Schnauzers, and Miniature Schnauzers with primary hypertriacylglycerolemia. A total of 35 healthy dogs of various breeds with serum triacylglycerol (TAG) and cholesterol concentrations within their respective reference intervals were selected for use as a reference population. Thirty-one Miniature Schnauzers with serum TAG and cholesterol concentrations within their respective reference intervals and 31 Miniature Schnauzers with hypertriacylglyceridemia were also included in the study. Results The results suggest that CLPDP using NaBiEDTA provides unique diagnostic information in addition to measurements of serum TAG and cholesterol concentrations and that it is a useful screening method for dogs with suspected lipoprotein metabolism disorders. Using the detailed and continuous density distribution information provided by the CLPDP, important differences in lipoprotein profiles can be detected even among dogs that have serum TAG and cholesterol concentrations within the reference interval. Miniature Schnauzers with serum TAG and cholesterol concentrations within the reference interval had significantly different lipoprotein profiles than dogs of various other breeds. In addition, it was further established that specific lipoprotein fractions are associated with hypertriacylglyceridemia in Miniature Schnauzers. Conclusions The results of the

Miniature Scroll Pumps Fabricated by LIGA

Science.gov (United States)

Wiberg, Dean; Shcheglov, Kirill; White, Victor; Bae, Sam

2009-01-01

Miniature scroll pumps have been proposed as roughing pumps (low - vacuum pumps) for miniature scientific instruments (e.g., portable mass spectrometers and gas analyzers) that depend on vacuum. The larger scroll pumps used as roughing pumps in some older vacuum systems are fabricated by conventional machining. Typically, such an older scroll pump includes (1) an electric motor with an eccentric shaft to generate orbital motion of a scroll and (2) conventional bearings to restrict the orbital motion to a circle. The proposed miniature scroll pumps would differ from the prior, larger ones in both design and fabrication. A miniature scroll pump would include two scrolls: one mounted on a stationary baseplate and one on a flexure stage (see figure). An electromagnetic actuator in the form of two pairs of voice coils in a push-pull configuration would make the flexure stage move in the desired circular orbit. The capacitance between the scrolls would be monitored to provide position (gap) feedback to a control system that would adjust the drive signals applied to the voice coils to maintain the circular orbit as needed for precise sealing of the scrolls. To minimize power consumption and maximize precision of control, the flexure stage would be driven at the frequency of its mechanical resonance. The miniaturization of these pumps would entail both operational and manufacturing tolerances of pump components. In addition, the vibrations of conventional motors and ball bearings exceed these tight tolerances by an order of magnitude. Therefore, the proposed pumps would be fabricated by the microfabrication method known by the German acronym LIGA ( lithographie, galvanoformung, abformung, which means lithography, electroforming, molding) because LIGA has been shown to be capable of providing the required tolerances at large aspect ratios.

Multiple distinct subtypes of GABAergic neurons in mouse visual cortex identified by triple immunostaining

Directory of Open Access Journals (Sweden)

Yuri Gonchar

2008-03-01

Full Text Available The majority of cortical interneurons use GABA (gamma amino butyric acid as inhibitory neurotransmitter. GABAergic neurons are morphologically, connectionally, electrically and chemically heterogeneous. In rat cerebral cortex three distinct groups of GABAergic interneurons have been identifi ed by the expression of parvalbumin (PV, calretinin (CR and somatostatin (SOM. Recent studies in mouse cerebral cortex have revealed a different organization in which the CR and SOM populations are partially overlapping. Because CR and SOM neurons derive from different progenitors located in different embryonic structures, the coexpression of CR + SOM suggests that the chemical differentiation of interneurons is regulated postmitotically. Here, we have taken an important fi rst step towards understanding this process by triple immunostaining mouse visual cortex with a panel of antibodies, which has been used extensively for classifying developing interneurons. We have found at least 13 distinct groups of GABAergic neurons which include PV, CR, SOM, CCK (cholecystokinin, CR + SOM, CR + NPY (neuropeptide Y, CR + VIP (vasointestinal polypeptide, SOM + NPY, SOM + VIP, VIP + ChAT (choline acetyltransferase, CCK + NPY, CR + SOM + NPY and CR + SOM + VIP expressing cells. Triple immunostaining with PV, CR and SOM antibodies during postnatal development further showed that PV is never colocalized with CR and SOM. Importantly, expression of SOM and CR + SOM developed after the percentage of CR cells that do not express SOM has reached the mature level, suggesting that the chemical differentiation of SOM and CR + SOM neurons is a postnatal event, which may be controlled by transcriptional regulation.

FY 2006 Miniature Spherical Retroreflectors Final Report

Energy Technology Data Exchange (ETDEWEB)

Anheier, Norman C.; Bernacki, Bruce E.; Krishnaswami, Kannan

2006-12-28

Research done by the Infrared Photonics team at Pacific Northwest National Laboratory (PNNL) is focused on developing miniature spherical retroreflectors using the unique optical and material properties of chalcogenide glass to reduce both performance limiting spherical aberrations. The optimized optical performance will provide efficient signal retroreflection that enables a broad range of remote detection scenarios for mid-wave infrared (MWIR) and long-wave infrared (LWIR) sensing applications. Miniature spherical retroreflectors can be developed to aid in the detection of signatures of nuclear proliferation or other chemical vapor or radiation signatures. Miniature spherical retroreflectors are not only well suited to traditional LIDAR methods for chemical plume detection and identification, but could enable remote detection of difficult semi-volatile chemical materials or low level radiation sources.

Miniature radioactive light source

International Nuclear Information System (INIS)

Caffarella, T.E.; Radda, G.J.; Dooley, H.H.

1980-01-01

A miniature radioactive light source for illuminating digital watches is described consisting of a glass tube with improved laser sealing and strength containing tritium gas and a transducer responsive to the gas. (U.K.)

GABAergic modulation of visual gamma and alpha oscillations and its consequences for working memory performance

NARCIS (Netherlands)

Lozano Soldevilla, D.; Huurne, N.; Cools, R.; Jensen, O.

2014-01-01

BACKGROUND: Impressive in vitro research in rodents and computational modeling has uncovered the core mechanisms responsible for generating neuronal oscillations. In particular, GABAergic interneurons play a crucial role for synchronizing neural populations. Do these mechanistic principles apply to

Aberrant Epigenetic Gene Regulation in GABAergic Interneuron Subpopulations in the Hippocampal Dentate Gyrus of Mouse Offspring Following Developmental Exposure to Hexachlorophene.

Science.gov (United States)

Watanabe, Yousuke; Abe, Hajime; Nakajima, Kota; Ideta-Otsuka, Maky; Igarashi, Katsuhide; Woo, Gye-Hyeong; Yoshida, Toshinori; Shibutani, Makoto

2018-05-01

Maternal hexachlorophene (HCP) exposure causes transient disruption of hippocampal neurogenesis in mouse offspring. We examined epigenetically hypermethylated and downregulated genes related to this HCP-induced disrupted neurogenesis. Mated female mice were dietary exposed to 0 or 100 ppm HCP from gestational day 6 to postnatal day (PND) 21 on weaning. The hippocampal dentate gyrus of male offspring was subjected to methyl-capture sequencing and real-time reverse transcription-polymerase chain reaction analyses on PND 21. Validation analyses on methylation identified three genes, Dlx4, Dmrt1, and Plcb4, showing promoter-region hypermethylation. Immunohistochemically, DLX4+, DMRT1+, and PLCB4+ cells in the dentate hilus co-expressed GAD67, a γ-aminobutyric acid (GABA)ergic neuron marker. HCP decreased all of three subpopulations as well as GAD67+ cells on PND 21. PLCB4+ cells also co-expressed the metabotropic glutamate receptor, GRM1. HCP also decreased transcript level of synaptic plasticity-related genes in the dentate gyrus and immunoreactive granule cells for synaptic plasticity-related ARC. On PND 77, all immunohistochemical cellular density changes were reversed, whereas the transcript expression of the synaptic plasticity-related genes fluctuated. Thus, HCP-exposed offspring transiently reduced the number of GABAergic interneurons. Among them, subpopulations expressing DLX4, DMRT1, or PLCB4 were transiently reduced in number through an epigenetic mechanism. Considering the role of the Dlx gene family in GABAergic interneuron migration and differentiation, the decreased number of DLX4+ cells may be responsible for reducing those GABAergic interneurons regulating neurogenesis. The effect on granule cell synaptic plasticity was sustained until the adult stage, and reduced GABAergic interneurons active in GRM1-PLCB4 signaling may be responsible for the suppression on weaning.

Neuroanatomic Relationships between the GABAergic and Serotonergic Systems in the Developing Human Medulla

Science.gov (United States)

Broadbelt, Kevin G.; Paterson, David S.; Rivera, Keith D.; Trachtenberg, Felicia L.; Kinney, Hannah C.

2010-01-01

γ-Amino butyric (GABA) critically influences serotonergic (5-HT) neurons in the raphé and extra-raphé of the medulla oblongata. In this study we hypothesize there are marked changes in the developmental profile of markers of the human medullary GABAergic system relative to the 5-HT system in early life. We used single- and double-label immunocytochemistry and tissue receptor autoradiography in 15 human medullae from fetal and infant cases ranging from 15 gestational weeks to 10 postnatal months, and compared our findings with an extensive 5-HT-related database in our laboratory. In the raphé obscurus, we identified two subsets of GABAergic neurons using glutamic acid decarboxylase (GAD65/67) immunostaining: one comprised of small, round neurons; the other, medium, spindle-shaped neurons. In three term medullae cases, positive immunoflorescent neurons for both tryptophan hydroxylase and GAD65/67 were counted within the raphé obscurus. This revealed approximately 6% of the total neurons counted in this nucleus expressed both GAD65/67 and TPOH suggesting co-production of GABA by a subset of 5-HT neurons. The distribution of GABAA binding was ubiquitous across medullary nuclei, with highest binding in the raphé obscurus. GABAA receptor subtypes α1 and α3 were expressed by 5-HT neurons, indicating the site of interaction of GABA with 5-HT neurons. These receptor subtypes and KCC2, a major chloride transporter, were differentially expressed across early development, from mid-gestation (20wks) and thereafter. The developmental profile of GABAergic markers changed dramatically relative to the 5-HT markers. These data provide baseline information for medullary studies of human pediatric disorders, such as sudden infant death syndrome. PMID:19926534

Impaired action potential initiation in GABAergic interneurons causes hyperexcitable networks in an epileptic mouse model carrying a human Na(V)1.1 mutation.

Science.gov (United States)

Hedrich, Ulrike B S; Liautard, Camille; Kirschenbaum, Daniel; Pofahl, Martin; Lavigne, Jennifer; Liu, Yuanyuan; Theiss, Stephan; Slotta, Johannes; Escayg, Andrew; Dihné, Marcel; Beck, Heinz; Mantegazza, Massimo; Lerche, Holger

2014-11-05

Mutations in SCN1A and other ion channel genes can cause different epileptic phenotypes, but the precise mechanisms underlying the development of hyperexcitable networks are largely unknown. Here, we present a multisystem analysis of an SCN1A mouse model carrying the NaV1.1-R1648H mutation, which causes febrile seizures and epilepsy in humans. We found a ubiquitous hypoexcitability of interneurons in thalamus, cortex, and hippocampus, without detectable changes in excitatory neurons. Interestingly, somatic Na(+) channels in interneurons and persistent Na(+) currents were not significantly changed. Instead, the key mechanism of interneuron dysfunction was a deficit of action potential initiation at the axon initial segment that was identified by analyzing action potential firing. This deficit increased with the duration of firing periods, suggesting that increased slow inactivation, as recorded for recombinant mutated channels, could play an important role. The deficit in interneuron firing caused reduced action potential-driven inhibition of excitatory neurons as revealed by less frequent spontaneous but not miniature IPSCs. Multiple approaches indicated increased spontaneous thalamocortical and hippocampal network activity in mutant mice, as follows: (1) more synchronous and higher-frequency firing was recorded in primary neuronal cultures plated on multielectrode arrays; (2) thalamocortical slices examined by field potential recordings revealed spontaneous activities and pathological high-frequency oscillations; and (3) multineuron Ca(2+) imaging in hippocampal slices showed increased spontaneous neuronal activity. Thus, an interneuron-specific generalized defect in action potential initiation causes multisystem disinhibition and network hyperexcitability, which can well explain the occurrence of seizures in the studied mouse model and in patients carrying this mutation. Copyright © 2014 the authors 0270-6474/14/3414874-16$15.00/0.

GABAergic actions on cholinergic laterodorsal tegmental neurons

DEFF Research Database (Denmark)

Kohlmeier, K A; Kristiansen, Uffe

2010-01-01

Cholinergic neurons of the pontine laterodorsal tegmentum (LDT) play a critical role in regulation of behavioral state. Therefore, elucidation of mechanisms that control their activity is vital for understanding of how switching between wakefulness, sleep and anesthetic states is effectuated....... In vivo studies suggest that GABAergic mechanisms within the pons play a critical role in behavioral state switching. However, the postsynaptic, electrophysiological actions of GABA on LDT neurons, as well as the identity of GABA receptors present in the LDT mediating these actions is virtually unexplored...... neurons. Post-synaptic location of GABA(A) receptors was demonstrated by persistence of muscimol-induced inward currents in TTX and low Ca(2+) solutions. THIP, a selective GABA(A) receptor agonist with a preference for d-subunit containing GABA(A) receptors, induced inward currents, suggesting...

Short-term repeated corticosterone administration enhances glutamatergic but not GABAergic transmission in the rat motor cortex.

Science.gov (United States)

Kula, Joanna; Blasiak, Anna; Czerw, Anna; Tylko, Grzegorz; Sowa, Joanna; Hess, Grzegorz

2016-04-01

It has been demonstrated that stress impairs performance of skilled reaching and walking tasks in rats due to the action of glucocorticoids involved in the stress response. Skilled reaching and walking are controlled by the primary motor cortex (M1); however, it is not known whether stress-related impairments in skilled motor tasks are related to functional and/or structural alterations within the M1. We studied the effects of single and repeated injections of corticosterone (twice daily for 7 days) on spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) recorded from layer II/III pyramidal neurons in ex vivo slices of the M1, prepared 2 days after the last administration of the hormone. We also measured the density of dendritic spines on pyramidal cells and the protein levels of selected subunits of AMPA, NMDA, and GABAA receptors after repeated corticosterone administration. Repeatedly administered corticosterone induced an increase in the frequency but not in the amplitude of sEPSCs, while a single administration had no effect on the recorded excitatory currents. The frequency and amplitude of sIPSCs as well as the excitability of pyramidal cells were changed neither after single nor after repeated corticosterone administration. Treatment with corticosterone for 7 days did not modify the density of dendritic spines on pyramidal neurons. Corticosterone influenced neither the protein levels of GluA1, GluA2, GluN1, GluN2A, and GluN2B subunits of glutamate receptors nor those of α1, β2, and γ2 subunits of the GABAA receptor. The increase in sEPSCs frequency induced by repeated corticosterone administration faded out within 7 days. These data indicate that prolonged administration of exogenous corticosterone selectively and reversibly enhances glutamatergic, but not GABAergic transmission in the rat motor cortex. Our results suggest that corticosterone treatment results in an enhancement of spontaneous glutamate release from presynaptic

Miniature Centrifugal Compressor

Science.gov (United States)

Sixsmith, Herbert

1989-01-01

Miniature turbocompressor designed for reliability and long life. Cryogenic system includes compressor, turboexpander, and heat exchanger provides 5 W of refrigeration at 70 K from 150 W input power. Design speed of machine 510,000 rpm. Compressor has gas-lubricated journal bearings and magnetic thrust bearing. When compressor runs no bearing contact and no wear.

Pharmacological treatment of fragile X syndrome with GABAergic drugs in a knockout mouse model

NARCIS (Netherlands)

Heulens, Inge; D'Hulst, Charlotte; Van Dam, Debby; De Deyn, Peter P.; Kooy, R. Frank

2012-01-01

Molecular and electrophysiological studies have provided evidence for a general downregulation of the GABAergic system in the Fmr1 knockout mouse. GABA(A) receptors are the main inhibitory receptors in the brain and the GABA(A) receptor was proposed as a novel target for treatment of the fragile X

Goniometry and Limb Girth in Miniature Dachshunds

OpenAIRE

Thomovsky, Stephanie A.; Chen, Annie V.; Kiszonas, Alecia M.; Lutskas, Lori A.

2016-01-01

Purpose. To report the mean and median pelvic limb joint angles and girth measurements in miniature Dachshunds presenting with varying degrees of pelvic limb weakness secondary to thoracolumbar intervertebral disc extrusion. Methods. 15 miniature Dachshunds who presented to WSU-VTH for thoracolumbar disc extrusion. Dachshunds varied in neurologic status from ambulatory paraparetic to paraplegic at the time of measurements. Results. There were no significant differences in joint angles or girt...

Miniaturized Environmental Monitoring Instrumentation

Energy Technology Data Exchange (ETDEWEB)

C. B. Freidhoff

1997-09-01

The objective of the Mass Spectrograph on a Chip (MSOC) program is the development of a miniature, multi-species gas sensor fabricated using silicon micromachining technology which will be orders of magnitude smaller and lower power consumption than a conventional mass spectrometer. The sensing and discrimination of this gas sensor are based on an ionic mass spectrograph, using magnetic and/or electrostatic fields. The fields cause a spatial separation of the ions according to their respective mass-to-charge ratio. The fabrication of this device involves the combination of microelectronics with micromechanically built sensors and, ultimately, vacuum pumps. The prototype of a chemical sensor would revolutionize the method of performing environmental monitoring for both commercial and government applications. The portable unit decided upon was the miniaturized gas chromatograph with a mass spectrometer detector, referred to as a GC/MS in the analytical marketplace.

Antenna Miniaturization with MEMS Tunable Capacitors

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

2014-01-01

In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss and their characterist......In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss...

Genetic Deletion of the Clathrin Adaptor GGA3 Reduces Anxiety and Alters GABAergic Transmission.

Directory of Open Access Journals (Sweden)

Kendall R Walker

Full Text Available Golgi-localized γ-ear-containing ARF binding protein 3 (GGA3 is a monomeric clathrin adaptor that has been shown to regulate the trafficking of the Beta-site APP-cleaving enzyme (BACE1, which is required for production of the Alzheimer's disease (AD-associated amyloid βpeptide. Our previous studies have shown that BACE1 is degraded via the lysosomal pathway and that depletion of GGA3 results in increased BACE1 levels and activity owing to impaired lysosomal trafficking and degradation. We further demonstrated the role of GGA3 in the regulation of BACE1 in vivo by showing that BACE1 levels are increased in the brain of GGA3 null mice. We report here that GGA3 deletion results in novelty-induced hyperactivity and decreased anxiety-like behaviors. Given the pivotal role of GABAergic transmission in the regulation of anxiety-like behaviors, we performed electrophysiological recordings in hippocampal slices and found increased phasic and decreased tonic inhibition in the dentate gyrus granule cells (DGGC. Moreover, we found that the number of inhibitory synapses is increased in the dentate gyrus of GGA3 null mice in further support of the electrophysiological data. Thus, the increased GABAergic transmission is a leading candidate mechanism underlying the reduced anxiety-like behaviors observed in GGA3 null mice. All together these findings suggest that GGA3 plays a key role in GABAergic transmission. Since BACE1 levels are elevated in the brain of GGA3 null mice, it is possible that at least some of these phenotypes are a consequence of increased processing of BACE1 substrates.

Genetic Deletion of the Clathrin Adaptor GGA3 Reduces Anxiety and Alters GABAergic Transmission.

Science.gov (United States)

Walker, Kendall R; Modgil, Amit; Albrecht, David; Lomoio, Selene; Haydon, Philip G; Moss, Stephen J; Tesco, Giuseppina

2016-01-01

Golgi-localized γ-ear-containing ARF binding protein 3 (GGA3) is a monomeric clathrin adaptor that has been shown to regulate the trafficking of the Beta-site APP-cleaving enzyme (BACE1), which is required for production of the Alzheimer's disease (AD)-associated amyloid βpeptide. Our previous studies have shown that BACE1 is degraded via the lysosomal pathway and that depletion of GGA3 results in increased BACE1 levels and activity owing to impaired lysosomal trafficking and degradation. We further demonstrated the role of GGA3 in the regulation of BACE1 in vivo by showing that BACE1 levels are increased in the brain of GGA3 null mice. We report here that GGA3 deletion results in novelty-induced hyperactivity and decreased anxiety-like behaviors. Given the pivotal role of GABAergic transmission in the regulation of anxiety-like behaviors, we performed electrophysiological recordings in hippocampal slices and found increased phasic and decreased tonic inhibition in the dentate gyrus granule cells (DGGC). Moreover, we found that the number of inhibitory synapses is increased in the dentate gyrus of GGA3 null mice in further support of the electrophysiological data. Thus, the increased GABAergic transmission is a leading candidate mechanism underlying the reduced anxiety-like behaviors observed in GGA3 null mice. All together these findings suggest that GGA3 plays a key role in GABAergic transmission. Since BACE1 levels are elevated in the brain of GGA3 null mice, it is possible that at least some of these phenotypes are a consequence of increased processing of BACE1 substrates.

miRNAs may regulate GABAergic transmission associated genes in aged rats with anesthetics-induced recognition and working memory dysfunction.

Science.gov (United States)

Shan, Ligang; Ma, Duo; Zhang, Chengshen; Xiong, Wei; Zhang, Yi

2017-09-01

Isoflurane and sevoflurane are widely used anesthetics in surgery and administration of these anesthetics could lead to postoperative cognitive dysfunction (POCD). However, the mechanisms remain unclear. Aged Wistar rats were exposed to isoflurane and sevoflurane for 2 or 4h. Recognition memory and spatial working memory were measured using Novel object recognition (NOR) and Y-maze test, respectively. Apoptotic cells were detected by TUNEL staining. miRNA expression was measured by Real-time PCR while protein expression was measured by Western blot. Dual-Luciferase reporter assay was used to establish the direct relationship between miRNAs and Gabra5 and gephyrin gene expression. Exposure to isoflurane and sevoflurane for 2 or 4h significantly decreased the NOR index in the NOR test and spontaneous alternations in arm entries in the Y-maze test in aged rats. TUNEL staining showed that isoflurane and sevoflurane administration significantly induced apoptosis in the mPFC and hippocampus. The protein level of α5 GABA A receptor (α5GABA A R), gephyrin, and dystrophin were significantly increased, whereas the expression of miR-30a, miR-31, miR-190a, and miR-190b was significantly decreased in the hippocampus and mPFC in aged rats exposed to isoflurane and sevoflurane compared to control rats. The protein levels of α5GABA A R, gephyrin, and dystrophin protein in the hippocampus and the mPFC significantly correlated with NOR index and spontaneous alternations. Dual-Luciferase reporter assay showed that miR-30a and miR-190a/b mimics significantly inhibited Gabra5 and gephyrin gene expression, respectively. There might be a miRNAs-GABAergic transmission pathway which may be involved in the pathophysiological alteration in anesthetics-induced POCD. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of Cortical GABAergic Neurons: Interplay of progenitor diversity and environmental factors on fate specification

Directory of Open Access Journals (Sweden)

Juliana Alves Brandão

2015-04-01

Full Text Available Cortical GABAergic interneurons constitute an extremely diverse population of cells organized in a well-defined topology of precisely interconnected cells. They play a crucial role regulating inhibitory-excitatory balance in brain circuits, gating sensory perception and regulating spike timing to brain oscillations during distinct behaviors. Dysfunctions in the establishment of proper inhibitory circuits have been associated to several brain disorders such as autism, epilepsy and schizophrenia. In the rodent adult cortex, inhibitory neurons are generated during the second gestational week from distinct progenitor lineages located in restricted domains of the ventral telencephalon. However, only recently, studies have revealed some of the mechanisms generating the heterogeneity of neuronal subtypes and their modes of integration in brain networks. Here we will discuss some the events involved in the production of cortical GABAergic neuron diversity with focus on the interaction between intrinsically driven genetic programs and environmental signals during development.

Research on Miniature Calibre Rail-Guns for the Mechanical Arm

Directory of Open Access Journals (Sweden)

Ronggang Cao

2017-01-01

Full Text Available Rail-gun should not only be used to military applications, but also can be developed as applications in the civilian aspects of the market. With the development of the electromagnetic launch technology, based on the similarity theory, using the existing rail-gun model to guide the construction of more economical miniature calibre rail-guns, and apply it in some machinery and equipment, this idea will open up a wider rail-gun application space. This article will focus on the feasibility of application of miniature calibre rail-guns in the mechanical arm. This paper designs the schematic diagram, then theoretical analyzes force conditions of the armature in the mechanical arm, calculates the possible range of the current amplitude and so on. The existing rail-gun model can be used to guides design the circuit diagram of the miniature calibre rail-gun. Based on the similarity theory and many simulation experiments, designed the experimental parameters of a miniature rail-gun and analyzed the current, Lorentz force, velocity, and location of the existing rail-gun and miniature rail-gun. The results show that the rail-gun launching technology applied to robot arms is feasibility. The application of miniature calibre rail-guns in the mechanical arm will benefit to the further development of rail-guns.

GABAergic activities control spike timing- and frequency-dependent long-term depression at hippocampal excitatory synapses

Directory of Open Access Journals (Sweden)

Makoto Nishiyama

2010-06-01

Full Text Available GABAergic interneuronal network activities in the hippocampus control a variety of neural functions, including learning and memory, by regulating θ and γ oscillations. How these GABAergic activities at pre- and post-synaptic sites of hippocampal CA1 pyramidal cells differentially contribute to synaptic function and plasticity during their repetitive pre- and post-synaptic spiking at θ and γ oscillations is largely unknown. We show here that activities mediated by postsynaptic GABAARs and presynaptic GABABRs determine, respectively, the spike timing- and frequency-dependence of activity-induced synaptic modifications at Schaffer collateral-CA1 excitatory synapses. We demonstrate that both feedforward and feedback GABAAR-mediated inhibition in the postsynaptic cell controls the spike timing-dependent long-term depression of excitatory inputs (“e-LTD” at the θ frequency. We also show that feedback postsynaptic inhibition specifically causes e-LTD of inputs that induce small postsynaptic currents (<70 pA with LTP timing, thus enforcing the requirement of cooperativity for induction of long-term potentiation at excitatory inputs (“e-LTP”. Furthermore, under spike-timing protocols that induce e-LTP and e-LTD at excitatory synapses, we observed parallel induction of LTP and LTD at inhibitory inputs (“i-LTP” and “i-LTD” to the same postsynaptic cells. Finally, we show that presynaptic GABABR-mediated inhibition plays a major role in the induction of frequency-dependent e-LTD at α and β frequencies. These observations demonstrate the critical influence of GABAergic interneuronal network activities in regulating the spike timing and frequency dependences of long-term synaptic modifications in the hippocampus.

GABAergic modulation of visual gamma and alpha oscillations and its consequences for working memory performance.

Science.gov (United States)

Lozano-Soldevilla, Diego; ter Huurne, Niels; Cools, Roshan; Jensen, Ole

2014-12-15

Impressive in vitro research in rodents and computational modeling has uncovered the core mechanisms responsible for generating neuronal oscillations. In particular, GABAergic interneurons play a crucial role for synchronizing neural populations. Do these mechanistic principles apply to human oscillations associated with function? To address this, we recorded ongoing brain activity using magnetoencephalography (MEG) in healthy human subjects participating in a double-blind pharmacological study receiving placebo, 0.5 mg and 1.5 mg of lorazepam (LZP; a benzodiazepine upregulating GABAergic conductance). Participants performed a demanding visuospatial working memory (WM) task. We found that occipital gamma power associated with WM recognition increased with LZP dosage. Importantly, the frequency of the gamma activity decreased with dosage, as predicted by models derived from the rat hippocampus. A regionally specific gamma increase correlated with the drug-related performance decrease. Despite the system-wide pharmacological intervention, gamma power drug modulations were specific to visual cortex: sensorimotor gamma power and frequency during button presses remained unaffected. In contrast, occipital alpha power modulations during the delay interval decreased parametrically with drug dosage, predicting performance impairment. Consistent with alpha oscillations reflecting functional inhibition, LZP affected alpha power strongly in early visual regions not required for the task demonstrating a regional specific occipital impairment. GABAergic interneurons are strongly implicated in the generation of gamma and alpha oscillations in human occipital cortex where drug-induced power modulations predicted WM performance. Our findings bring us an important step closer to linking neuronal dynamics to behavior by embracing established animal models. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modulation of Network Oscillatory Activity and GABAergic Synaptic Transmission by CB1 Cannabinoid Receptors in the Rat Medial Entorhinal Cortex

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Nicola H. Morgan

2008-01-01

Full Text Available Cannabinoids modulate inhibitory GABAergic neurotransmission in many brain regions. Within the temporal lobe, cannabinoid receptors are highly expressed, and are located presynaptically at inhibitory terminals. Here, we have explored the role of type-1 cannabinoid receptors (CB1Rs at the level of inhibitory synaptic currents and field-recorded network oscillations. We report that arachidonylcyclopropylamide (ACPA; 10 M, an agonist at CB1R, inhibits GABAergic synaptic transmission onto both superficial and deep medial entorhinal (mEC neurones, but this has little effect on network oscillations in beta/gamma frequency bands. By contrast, the CB1R antagonist/inverse agonist LY320135 (500 nM, increased GABAergic synaptic activity and beta/gamma oscillatory activity in superficial mEC, was suppressed, whilst that in deep mEC was enhanced. These data indicate that cannabinoid-mediated effects on inhibitory synaptic activity may be constitutively active in vitro, and that modulation of CB1R activation using inverse agonists unmasks complex effects of CBR function on network activity.

A Miniature Recording Cardiotachometer

DEFF Research Database (Denmark)

Zsombor-Murray, Paul J; Vroomen, Louis J.; Hendriksen, Nils Thedin

1981-01-01

The design of a miniature, recording cardiotachometer is described. It is simple and can store digital data. Bench and field tests, using a hand-held display, are presented. Construction and principles of operation are discussed. Applications, with performing athlete subjects, are outlined....

Miniature Optical Isolator, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — To address NASA's need for compact optical isolators, Physical Optics Corporation (POC) proposes to continue the development of a new Miniature Optical Isolator...

Metabolism regulates the spontaneous firing of substantia nigra pars reticulata neurons via KATP and nonselective cation channels.

Science.gov (United States)

Lutas, Andrew; Birnbaumer, Lutz; Yellen, Gary

2014-12-03

Neurons use glucose to fuel glycolysis and provide substrates for mitochondrial respiration, but neurons can also use alternative fuels that bypass glycolysis and feed directly into mitochondria. To determine whether neuronal pacemaking depends on active glucose metabolism, we switched the metabolic fuel from glucose to alternative fuels, lactate or β-hydroxybutyrate, while monitoring the spontaneous firing of GABAergic neurons in mouse substantia nigra pars reticulata (SNr) brain slices. We found that alternative fuels, in the absence of glucose, sustained SNr spontaneous firing at basal rates, but glycolysis may still be supported by glycogen in the absence of glucose. To prevent any glycogen-fueled glycolysis, we directly inhibited glycolysis using either 2-deoxyglucose or iodoacetic acid. Inhibiting glycolysis in the presence of alternative fuels lowered SNr firing to a slower sustained firing rate. Surprisingly, we found that the decrease in SNr firing was not mediated by ATP-sensitive potassium (KATP) channel activity, but if we lowered the perfusion flow rate or omitted the alternative fuel, KATP channels were activated and could silence SNr firing. The KATP-independent slowing of SNr firing that occurred with glycolytic inhibition in the presence of alternative fuels was consistent with a decrease in a nonselective cationic conductance. Although mitochondrial metabolism alone can prevent severe energy deprivation and KATP channel activation in SNr neurons, active glucose metabolism appears important for keeping open a class of ion channels that is crucial for the high spontaneous firing rate of SNr neurons. Copyright © 2014 the authors 0270-6474/14/3416336-12$15.00/0.

Continuous flow nitration in miniaturized devices

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Amol A. Kulkarni

2014-02-01

Full Text Available This review highlights the state of the art in the field of continuous flow nitration with miniaturized devices. Although nitration has been one of the oldest and most important unit reactions, the advent of miniaturized devices has paved the way for new opportunities to reconsider the conventional approach for exothermic and selectivity sensitive nitration reactions. Four different approaches to flow nitration with microreactors are presented herein and discussed in view of their advantages, limitations and applicability of the information towards scale-up. Selected recent patents that disclose scale-up methodologies for continuous flow nitration are also briefly reviewed.

Goniometry and Limb Girth in Miniature Dachshunds

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Stephanie A. Thomovsky

2016-01-01

Full Text Available Purpose. To report the mean and median pelvic limb joint angles and girth measurements in miniature Dachshunds presenting with varying degrees of pelvic limb weakness secondary to thoracolumbar intervertebral disc extrusion. Methods. 15 miniature Dachshunds who presented to WSU-VTH for thoracolumbar disc extrusion. Dachshunds varied in neurologic status from ambulatory paraparetic to paraplegic at the time of measurements. Results. There were no significant differences in joint angles or girth among the three groups (ambulatory paraparetic, nonambulatory paraparetic, or paraplegic (P>0.05. When group was disregarded and values for extension, flexion, and girth combined, no differences existed. Conclusions. Goniometry and limb girth measurements can successfully be made in the miniature Dachshund; however, the shape of the Dachshund leg makes obtaining these values challenging. There were no differences in joint angle or girth measurements between dogs with varying neurologic dysfunction at the time of measurement.

Goniometry and Limb Girth in Miniature Dachshunds.

Science.gov (United States)

Thomovsky, Stephanie A; Chen, Annie V; Kiszonas, Alecia M; Lutskas, Lori A

2016-01-01

Purpose. To report the mean and median pelvic limb joint angles and girth measurements in miniature Dachshunds presenting with varying degrees of pelvic limb weakness secondary to thoracolumbar intervertebral disc extrusion. Methods. 15 miniature Dachshunds who presented to WSU-VTH for thoracolumbar disc extrusion. Dachshunds varied in neurologic status from ambulatory paraparetic to paraplegic at the time of measurements. Results. There were no significant differences in joint angles or girth among the three groups (ambulatory paraparetic, nonambulatory paraparetic, or paraplegic) (P > 0.05). When group was disregarded and values for extension, flexion, and girth combined, no differences existed. Conclusions. Goniometry and limb girth measurements can successfully be made in the miniature Dachshund; however, the shape of the Dachshund leg makes obtaining these values challenging. There were no differences in joint angle or girth measurements between dogs with varying neurologic dysfunction at the time of measurement.

Pricing of miniature vehicles made from telephone card waste

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Puspitasari, N. B.; Pujotomo, D.; Muhardiansyah, H.

2017-12-01

The number of electronic devices in Indonesia in the last 10 years has been increasing quite drastically which contributes to more electronic waste. E-waste or electronic waste have different characteristics from other kinds of waste. Components of electronic waste often poisonous, consisting dangerous chemicals. The telephone card wasted is also an electronic waste. One alternative to handle and manage telephone card waste is to recycle it into collectible miniature vehicles. But the price of these miniatures is quite high, causing low interest in buying them. A research on the price of miniature vehicles in relation to consumers’ Ability to Pay (ATP) and Willingness to Pay (WTP) needs to be done. Segmentation analysis data, target, product positioning and product marketing mix are needed before commencing the research. Data collection is done through a survey by spreading questionnaire to 100 miniature vehicle collectors in Semarang, questioning their ability and willingness to pay recycled miniature vehicles. Calculations showed average ATP of Rp.112.520, 24 and average WTP of Rp.76.870. The last result showed the estimate pricing according to ATP and WTP which is Rp.66.000 with 58% of the respondents claiming to be willing and able to pay that price.

Miniature UAVs : An overview

NARCIS (Netherlands)

Weimar, P.W.L.; Kerkkamp, J.S.F.; Wiel, R.A.N.; Meiller, P.P.; Bos, J.G.H.

2014-01-01

With this book TNO provides an overview of topics related to Miniature Unmanned Aerial Vehicles (MUAVs). Both novices and experts may find this publication valuable. The Netherlands Organisation for Applied Scientific Research TNO conducts research on UAVs and MUAVs, see for example [1], on the

Role of CB1 cannabinoid receptors on GABAergic neurons in brain aging.

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Albayram, Onder; Alferink, Judith; Pitsch, Julika; Piyanova, Anastasia; Neitzert, Kim; Poppensieker, Karola; Mauer, Daniela; Michel, Kerstin; Legler, Anne; Becker, Albert; Monory, Krisztina; Lutz, Beat; Zimmer, Andreas; Bilkei-Gorzo, Andras

2011-07-05

Brain aging is associated with cognitive decline that is accompanied by progressive neuroinflammatory changes. The endocannabinoid system (ECS) is involved in the regulation of glial activity and influences the progression of age-related learning and memory deficits. Mice lacking the Cnr1 gene (Cnr1(-/-)), which encodes the cannabinoid receptor 1 (CB1), showed an accelerated age-dependent deficit in spatial learning accompanied by a loss of principal neurons in the hippocampus. The age-dependent decrease in neuronal numbers in Cnr1(-/-) mice was not related to decreased neurogenesis or to epileptic seizures. However, enhanced neuroinflammation characterized by an increased density of astrocytes and activated microglia as well as an enhanced expression of the inflammatory cytokine IL-6 during aging was present in the hippocampus of Cnr1(-/-) mice. The ongoing process of pyramidal cell degeneration and neuroinflammation can exacerbate each other and both contribute to the cognitive deficits. Deletion of CB1 receptors from the forebrain GABAergic, but not from the glutamatergic neurons, led to a similar neuronal loss and increased neuroinflammation in the hippocampus as observed in animals lacking CB1 receptors in all cells. Our results suggest that CB1 receptor activity on hippocampal GABAergic neurons protects against age-dependent cognitive decline by reducing pyramidal cell degeneration and neuroinflammation.

Femtosecond laser-assisted cataract surgery and implantable miniature telescope

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Randal Pham

2017-09-01

Conclusions and importance: To our knowledge and confirmed by the manufacturer of the implantable miniature telescope this is the first case ever reported of a patient who has undergone femtosecond laser cataract surgery with corneal astigmatism correction and implantation of the implantable miniature telescope. This is also the first case report of the preoperative use of microperimetry and visual electrophysiology to evaluate a patient's postoperative potential visual acuity. The success of the procedure illustrated the importance of meticulous preoperative planning, the combined use of state-of-the-art technologies and the seamless teamwork in order to achieve the best clinical outcome for patients who undergo implantation of the implantable miniature telescope.

Gradual Changes of Gut Microbiota in Weaned Miniature Piglets

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Xianghua Yan

2016-11-01

Full Text Available Colonization of gut microbiota in mammals during the early life is vital to host health. The miniature piglet has recently been considered as an optimal infant model. However, less is known about the development of gut microbiota in miniature piglets. Here, this study was conducted to explore how the gut microbiota develops in weaned Congjiang miniature piglets. In contrast to the relatively stabilized gut fungal community, gut bacterial community showed a marked drop in alpha diversity, accompanied by significant alterations in taxonomic compositions. The relative abundances of 24 bacterial genera significantly declined, whereas the relative abundances of 7 bacterial genera (Fibrobacter, Collinsella, Roseburia, Prevotella, Dorea, Howardella, and Blautia significantly increased with the age of weaned piglets. Fungal taxonomic analysis showed that the relative abundances of 2 genera (Kazachstania and Aureobasidium significantly decreased, whereas the relative abundances of 4 genera (Aspergillus, Cladosporium, Simplicillium, and Candida significantly increased as the piglets aged. Kazachstania telluris was the signature species predominated in gut fungal communities of weaned miniature piglets. The functional maturation of the gut bacterial community was characterized by the significantly increased digestive system, glycan biosynthesis and metabolism, and vitamin B biosynthesis as the piglets aged. These findings suggest that marked gut microbial changes in Congjiang miniature piglets may contribute to understand the potential gut microbiota development of weaned infants.

Expression of GABAergic receptors in mouse taste receptor cells.

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Margaret R Starostik

Full Text Available BACKGROUND: Multiple excitatory neurotransmitters have been identified in the mammalian taste transduction, with few studies focused on inhibitory neurotransmitters. Since the synthetic enzyme glutamate decarboxylase (GAD for gamma-aminobutyric acid (GABA is expressed in a subset of mouse taste cells, we hypothesized that other components of the GABA signaling pathway are likely expressed in this system. GABA signaling is initiated by the activation of either ionotropic receptors (GABA(A and GABA(C or metabotropic receptors (GABA(B while it is terminated by the re-uptake of GABA through transporters (GATs. METHODOLOGY/PRINCIPAL FINDINGS: Using reverse transcriptase-PCR (RT-PCR analysis, we investigated the expression of different GABA signaling molecules in the mouse taste system. Taste receptor cells (TRCs in the circumvallate papillae express multiple subunits of the GABA(A and GABA(B receptors as well as multiple GATs. Immunocytochemical analyses examined the distribution of the GABA machinery in the circumvallate papillae. Both GABA(A-and GABA(B- immunoreactivity were detected in the peripheral taste receptor cells. We also used transgenic mice that express green fluorescent protein (GFP in either the Type II taste cells, which can respond to bitter, sweet or umami taste stimuli, or in the Type III GAD67 expressing taste cells. Thus, we were able to identify that GABAergic receptors are expressed in some Type II and Type III taste cells. Mouse GAT4 labeling was concentrated in the cells surrounding the taste buds with a few positively labeled TRCs at the margins of the taste buds. CONCLUSIONS/SIGNIFICANCE: The presence of GABAergic receptors localized on Type II and Type III taste cells suggests that GABA is likely modulating evoked taste responses in the mouse taste bud.

DEVELOPMENTAL HYPOTHYROIDISM REDUCES PARVALBUMIN EXPRESSION IN GABAERGIC NEURONS OF CORTEX AND HIPPOCAMPUS: IMMUNOHISTOCHEMICAL FINDINGS AND FUNCTIONAL CORRELATES.

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GABAergic interneurons comprise the bulk of local inhibitory neuronal circuitry in cortex and hippocampus and a subpopulation of these interneurons contain the calcium binding protein, parvalbumin (PV). A previous report indicated that severe hypothyroidism reduced PV immunoreact...

Miniature, Single Channel, Memory-Based, High-G Acceleration Recorder (Millipen)

International Nuclear Information System (INIS)

Rohwer, Tedd A.

1999-01-01

The Instrumentation and Telemetry Departments at Sandia National Laboratories have been instrumenting earth penetrators for over thirty years. Recorded acceleration data is used to quantify penetrator performance. Penetrator testing has become more difficult as desired impact velocities have increased. This results in the need for small-scale test vehicles and miniature instrumentation. A miniature recorder will allow penetrator diameters to significantly decrease, opening the window of testable parameters. Full-scale test vehicles will also benefit from miniature recorders by using a less intrusive system to instrument internal arming, fusing, and firing components. This single channel concept is the latest design in an ongoing effort to miniaturize the size and reduce the power requirement of acceleration instrumentation. A micro-controller/memory based system provides the data acquisition, signal conditioning, power regulation, and data storage. This architecture allows the recorder, including both sensor and electronics, to occupy a volume of less than 1.5 cubic inches, draw less than 200mW of power, and record 15kHz data up to 40,000 gs. This paper will describe the development and operation of this miniature acceleration recorder

Damage of GABAergic neurons in the medial septum impairs spatial working memory and extinction of active avoidance: effects on proactive interference.

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Pang, Kevin C H; Jiao, Xilu; Sinha, Swamini; Beck, Kevin D; Servatius, Richard J

2011-08-01

The medial septum and diagonal band (MSDB) are important in spatial learning and memory. On the basis of the excitotoxic damage of GABAergic MSDB neurons, we have recently suggested a role for these neurons in controlling proactive interference. Our study sought to test this hypothesis in different behavioral procedures using a new GABAergic immunotoxin. GABA-transporter-saporin (GAT1-SAP) was administered into the MSDB of male Sprague-Dawley rats. Following surgery, rats were trained in a reference memory water maze procedure for 5 days, followed by a working memory (delayed match to position) water maze procedure. Other rats were trained in a lever-press avoidance procedure after intraseptal GAT1-SAP or sham surgery. Intraseptal GAT1-SAP extensively damaged GABAergic neurons while sparing most cholinergic MSDB neurons. Rats treated with GAT1-SAP were not impaired in acquiring a spatial reference memory, learning the location of the escape platform as rapidly as sham rats. In contrast, GAT1-SAP rats were slower than sham rats to learn the platform location in a delayed match to position procedure, in which the platform location was changed every day. Moreover, GAT1-SAP rats returned to previous platform locations more often than sham rats. In the active avoidance procedure, intraseptal GAT1-SAP impaired extinction but not acquisition of the avoidance response. Using a different neurotoxin and behavioral procedures than previous studies, the results of this study paint a similar picture that GABAergic MSDB neurons are important for controlling proactive interference. Copyright © 2010 Wiley-Liss, Inc.

Chronic restraint stress impairs endocannabinoid mediated suppression of GABAergic signaling in the hippocampus of adult male rats.

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Hu, Wen; Zhang, Mingyue; Czéh, Boldizsár; Zhang, Weiqi; Flügge, Gabriele

2011-07-15

Chronic stress, a risk factor for the development of psychiatric disorders, is known to induce alterations in neuronal networks in many brain areas. Previous studies have shown that chronic stress changes the expression of the cannabinoid receptor 1 (CB1) in the brains of adult rats, but neurophysiological consequences of these changes remained unclear. Here we demonstrate that chronic restraint stress causes a dysfunction in CB1 mediated modulation of GABAergic transmission in the hippocampus. Using an established protocol, adult male Sprague Dawley rats were daily restrained for 21 days and whole-cell voltage clamp was performed at CA1 pyramidal neurons. When recording carbachol-evoked inhibitory postsynaptic currents (IPSCs) which presumably originate from CB1 expressing cholecystokinin (CCK) interneurons, we found that depolarization-induced suppression of inhibition (DSI) was impaired by the stress. DSI is a form of short-term plasticity at GABAergic synapses that is known to be CB1 mediated and has been suggested to be involved in hippocampal information encoding. Chronic stress attenuated the depolarization-induced suppression of the frequency of carbachol-evoked IPSCs. Incubation with a CB1 receptor antagonist prevented this DSI effect in control but not in chronically stressed animals. The stress-induced impairment of CB1-mediated short-term plasticity at GABAergic synapses may underlie cognitive deficits which are commonly observed in animal models of stress as well as in patients with stress-related psychiatric disorders. Copyright © 2011 Elsevier Inc. All rights reserved.

The Textile Elements in Ottoman Miniatures

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Kevser Gürcan Y A R D I M C I

2015-07-01

Full Text Available With the value given to the art and the artist, high quality works of art in many fields were produced in the Ottoman Era. The art of weaving also lived its brightest period in terms of color, design, and weaving techniques in the Ottoman Empire in XVI. Ce ntury. The weaving products shaped the lifestyles of the people in those times and received great interest in the Palace as well. Silk woven fabrics had become such a great power in those times that it became the greatest symbol showing the power of the Ot toman Empire to the foreigners, and the determiner of the social standing within the society. The Ottoman Sultans used their clothing, which they made to become flamboyant with embroideries, to distinguish themselves from the public, and make them accept t heir power. Among the presents that were presented to the Sultans, clothes, kaftans, and similar fabrics as well as other precious presents, were frequent. The miniature manuscripts that were produced in the Palace are in the quality of unique documents t hat transfer yesterday’s knowledge to the modern age. It is easy to decode the dimensions of the clothing habits, decoration elements and hierarchy concepts of the Ottoman Era, as well as the weaving activities by using the miniature manuscripts. On the ot her hand, these elements constitute a rich alphabet in transferring the emotional structure of the society in those times, the traditions and habits to our world today. The greatest share in this effort belongs to the artists who depicted the miniatures by staying loyal to the texts in the manuscripts as well as to their active participation in the events of those times and their narrating the events as the very first observers. In addition, the muralists depicting the manuscripts and their undertaking the job of drawing the designs on the original fabric helped them to reflect the richness in the design of those times to the miniatures. In this study, the weavings and the accessories

Miniaturized nuclear battery

International Nuclear Information System (INIS)

Adler, K.; Ducommun, G.

1976-01-01

The invention relates to a miniaturized nuclear battery, consisting of several in series connected cells, wherein each cell contains a support which acts as positive pole and which supports on one side a β-emitter, above said emitter is a radiation resisting insulation layer which is covered by an absorption layer, above which is a collector layer, and wherein the in series connected calls are disposed in an airtight case

Variable recruitment in bundles of miniature pneumatic artificial muscles.

Science.gov (United States)

DeLaHunt, Sylvie A; Pillsbury, Thomas E; Wereley, Norman M

2016-09-13

The natural compliance and force generation properties of pneumatic artificial muscles (PAMs) allow them to operate like human muscles in anthropomorphic robotic manipulators. Traditionally, manipulators use a single PAM or multiple PAMs actuated in unison in place of a human muscle. However, these standard manipulators can experience significant efficiency losses when operated outside their target performance ranges at low actuation pressures. This study considers the application of a variable recruitment control strategy to a parallel bundle of miniature PAMs as an attempt to mimic the selective recruitment of motor units in a human muscle. Bundles of miniature PAMs are experimentally characterized, their actuation behavior is modeled, and the efficiency gains and losses associated with the application of a variable recruitment control strategy are assessed. This bio-inspired control strategy allows muscle bundles to operate the fewest miniature PAMs necessary to achieve a desired performance objective, improving the muscle bundle's operating efficiency over larger ranges of force generation and displacement. The study also highlights the need for improved PAM fabrication techniques to facilitate the production of identical miniature PAMs for inclusion in muscle bundles.

Miniature Blimps for Surveillance and Collection of Samples

Science.gov (United States)

Jones, Jack

2004-01-01

Miniature blimps are under development as robots for use in exploring the thick, cold, nitrogen atmosphere of Saturn's moon, Titan. Similar blimps can also be used for surveillance and collection of biochemical samples in buildings, caves, subways, and other, similar structures on Earth. The widely perceived need for means to thwart attacks on buildings and to mitigate the effects of such attacks has prompted consideration of the use of robots. Relative to rover-type (wheeled) robots that have been considered for such uses, miniature blimps offer the advantage of ability to move through the air in any direction and, hence, to perform tasks that are difficult or impossible for wheeled robots, including climbing stairs and looking through windows. In addition, miniature blimps are expected to have greater range and to cost less, relative to wheeled robots.

Miniature scientific-grade induction magnetometer for cubesats

Science.gov (United States)

Pronenko, Vira

2017-04-01

One of the main areas of space research is the study and forecasting of space weather. The society is more and more depending nowadays on satellite technology and communications, so it is vital to understand the physical process in the solar-terrestrial system which may disturb them. Besides the solar radiation and Space Weather effects, the Earth's ionosphere is also modified by the ever increasing industrial activity. There have been also multiple reports relating VLF and ELF wave activity to atmospheric storms and geological processes, such as earthquakes and volcanic activity. For advancing in these fields, the AC magnetic field permanent monitoring is crucial. Using the cubesat technology would allow increasing the number of measuring points dramatically. It is necessary to mention that the cubesats use for scientific research requires the miniaturization of scientific sensors what is a serious problem because the reduction of their dimensions leads, as a rule, to the parameters degradation, especially of sensitivity threshold. Today, there is no basic model of a sensitive miniature induction magnetometer. Even the smallest one of the known - for the Bepi-Colombo mission to Mercury - is too big for cubesats. The goal of the present report is to introduce the new design of miniature three-component sensor for measurement of alternative vector magnetic fields - induction magnetometer (IM). The study directions were concentrated on the ways and possibilities to create the miniature magnetometer with best combination of parameters. For this a set of scientific and technological problems, mostly aimed at the sensor construction improvement, was solved. The most important parameter characterizing magnetometer quality is its own magnetic noise level (NL). The analysis of the NL influencing factors is made and the ways to decrease it are discussed in the report. Finally, the LEMI-151 IM was developed for the SEAM cubesat mission with optimal performances within the

Variant BDNF-Val66Met Polymorphism is Associated with Layer-Specific Alterations in GABAergic Innervation of Pyramidal Neurons, Elevated Anxiety and Reduced Vulnerability of Adolescent Male Mice to Activity-Based Anorexia.

Science.gov (United States)

Chen, Yi-Wen; Surgent, Olivia; Rana, Barkha S; Lee, Francis; Aoki, Chiye

2017-08-01

Previously, we determined that rodents' vulnerability to food restriction (FR)-evoked wheel running during adolescence (activity-based anorexia, ABA) is associated with failures to increase GABAergic innervation of hippocampal and medial prefrontal pyramidal neurons. Since brain-derived neurotrophic factor (BDNF) promotes GABAergic synaptogenesis, we hypothesized that individual differences in this vulnerability may arise from differences in the link between BDNF bioavailability and FR-evoked wheel running. We tested this hypothesis in male BDNF-Val66Met knock-in mice (BDNFMet/Met), known for reduction in the activity-dependent BDNF secretion and elevated anxiety-like behaviors. We found that 1) in the absence of FR or a wheel (i.e., control), BDNFMet/Met mice are more anxious than wild-type (WT) littermates, 2) electron microscopically verified GABAergic innervations of pyramidal neurons of BDNFMet/Met mice are reduced at distal dendrites in hippocampal CA1 and medial prefrontal cortex, 3) following ABA, WT mice exhibit anxiety equal to those of the BDNFMet/Met mice and have lost GABAergic innervation along distal dendrites, 4) BDNFMet/Met mice show blunted ABA vulnerability, and 5) unexpectedly, GABAergic innervation is higher at somata of BDNFMet/Met mice than of WT. We conclude that lamina-specific GABAergic inhibition is important for regulating anxiety, whether arising from environmental stress, such as food deprivation, or genetically, such as BDNFMet/Met single nucleotide polymorphism. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Miniature Ground Mapping LADAR, Phase I

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National Aeronautics and Space Administration — System & Processes Engineering Corporation (SPEC) proposes a miniature solid state surface imaging LADAR, for imaging the landing areas providing precision...

Expression of glutamic acid decarboxylase and identification of GABAergic cells in the ischemic rat dentate gyrus

DEFF Research Database (Denmark)

Müller, Georg Johannes; Dogonowski, Anne-Marie; Finsen, Bente

2006-01-01

We have investigated the glutamic acid dexcarboxylase (GAD) mRNA and protein isoforms as markers for ischemic loss of GABAergic neurons in the dentate hilus. Stereological counts of these neurons were performed in rats surviving 8 days after 10 min of transient forebrain ischemia, and in control...

Miniature Pulpotomy of Symptomatic Mature Permanent Teeth: A Report of Two Cases.

Science.gov (United States)

Asgary, Saeed; Nourzadeh, Mahdieh; Eghbal, Mohammad Jafar

2016-01-01

Human dental pulp inflammation can progress to periapical lesion formation and conventional root canal treatment (RCT) has been the traditional method for disease management. This observational study presents two cases of vital pulp therapy in mature molars diagnosed with irreversible pulpitis and associated with apical periodontitis. In these two clinical cases, the involved teeth had deep carious lesions with a history of spontaneous/lingering pain and radiographic examinations revealed the presence of apical radiolucencies. A conservative miniature pulpotomy (MP) using calcium-enriched mixture (CEM) was performed and the teeth were permanently restored with amalgam. Clinical evaluations indicated resolution of pain 24 hours after treatment; the teeth showed normal vitality, remained asymptomatic and maintained normal function after recall examinations. Furthermore, the 18-month radiographic evaluation showed healing of the apical lesions. Vital pulp therapy using the MP technique with CEM appeared successful in avoiding RCT intervention. These two reports of case outcome suggest that simple MP using a CEM bioregenerative technique may provide a favorable outcome for permanent teeth diagnosed with irreversible pulpitis and associated with apical periodontitis.

Synthetic ciguatoxin CTX 3C induces a rapid imbalance in neuronal excitability.

Science.gov (United States)

Martín, Victor; Vale, Carmen; Hirama, Masahiro; Yamashita, Shuji; Rubiolo, Juan Andrés; Vieytes, Mercedes R; Botana, Luis M

2015-06-15

Ciguatera is a human global disease caused by the consumption of contaminated fish that have accumulated ciguatoxins (CTXs), sodium channel activator toxins. Symptoms of ciguatera include neurological alterations such as paraesthesiae, dysaesthesiae, depression, and heightened nociperception, among others. An important issue to understand these long-term neurological alterations is to establish the role that changes in activity produced by CTX 3C represent to neurons. Here, the effects of synthetic ciguatoxin CTX 3C on membrane potential, spontaneous spiking, and properties of synaptic transmission in cultured cortical neurons of 11-18 days in vitro (DIV) were evaluated using electrophysiological approaches. CTX 3C induced a large depolarization that decreased neuronal firing and caused a rapid inward tonic current that was primarily GABAergic. Moreover, the toxin enhanced the amplitude of miniature postsynaptic inhibitory currents (mIPSCs), whereas it decreased the amplitude of miniature postsynaptic excitatory currents (mEPSCs). The frequency of mIPSCs increased, whereas the frequency of mEPSCs remained unaltered. We describe, for the first time, that a rapid membrane depolarization caused by CTX 3C in cortical neurons activates mechanisms that tend to suppress electrical activity by shifting the balance between excitatory and inhibitory synaptic transmission toward inhibition. Indeed, these results suggest that the acute effects of CTX on synaptic transmission could underlie some of the neurological symptoms caused by ciguatera in humans.

Short-term ionic plasticity at GABAergic synapses

Directory of Open Access Journals (Sweden)

Joseph Valentino Raimondo

2012-10-01

Full Text Available Fast synaptic inhibition in the brain is mediated by the pre-synaptic release of the neurotransmitter γ-Aminobutyric acid (GABA and the post-synaptic activation of GABA-sensitive ionotropic receptors. As with excitatory synapses, it is being increasinly appreciated that a variety of plastic processes occur at inhibitory synapses, which operate over a range of timescales. Here we examine a form of activity-dependent plasticity that is somewhat unique to GABAergic transmission. This involves short-lasting changes to the ionic driving force for the postsynaptic receptors, a process referred to as short-term ionic plasticity. These changes are directly related to the history of activity at inhibitory synapses and are influenced by a variety of factors including the location of the synapse and the post-synaptic cell’s ion regulation mechanisms. We explore the processes underlying this form of plasticity, when and where it can occur, and how it is likely to impact network activity.

Steroid influences on GABAergic neurotransmission: A behavioral and biochemical approach

International Nuclear Information System (INIS)

McCarthy, M.M.

1989-01-01

Steroid influences on GABAergic neurotransmission are varied and complex. However, there has been little investigation into the behavioral relevance of steroid effects on GABA. GABA had been implicated in the control of lordosis, a steroid dependent posture exhibited by sexually receptive female rats, but with conflicting results. This data demonstrated that GABA plays a dual role in the regulation of lordosis; stimulation of GABAergic transmission in the medial hypothalamus enhances lordosis whereas stimulation of GABA in the preoptic area inhibits lordosis. In separate experiments it was determined that progesterone enhances binding of the GABA A agonist, muscimol, in an in vitro exchange assay utilizing synaptic membranes prepared from the hypothalamus of ovariectomized rats. Scatchard analysis revealed a difference in affinity of the GABA A receptor between ovariectomized, receptive and post receptive females. In the preoptic area there was a significant decrease in the binding of 3 H-muscimol in receptive females versus post-receptive and ovariectomized rats. In other behavioral experiments, the influence of estrogen and progesterone on GABA-induced analgesia was assessed. Intrathecal infusion of a low dose of muscimol at the lumbar level of the spinal cord did not alter nociceptive thresholds in ovariectomized rats. However, when intact females were administered the same dose of muscimol, they exhibited differential responses over the estrous cycle. Females in estrus were analgesic after muscimol, whereas diestrus females did not differ from ovariectomized controls. Ovariectomized rats injected s.c. with progesterone (2mg) exhibited a pronounced analgesia after intrathecal muscimol beginning 15 minutes after steroid treatment, whereas similar treatment with estrogen (10ug) was without effect

Autonomous stair-climbing with miniature jumping robots.

Science.gov (United States)

Stoeter, Sascha A; Papanikolopoulos, Nikolaos

2005-04-01

The problem of vision-guided control of miniature mobile robots is investigated. Untethered mobile robots with small physical dimensions of around 10 cm or less do not permit powerful onboard computers because of size and power constraints. These challenges have, in the past, reduced the functionality of such devices to that of a complex remote control vehicle with fancy sensors. With the help of a computationally more powerful entity such as a larger companion robot, the control loop can be closed. Using the miniature robot's video transmission or that of an observer to localize it in the world, control commands can be computed and relayed to the inept robot. The result is a system that exhibits autonomous capabilities. The framework presented here solves the problem of climbing stairs with the miniature Scout robot. The robot's unique locomotion mode, the jump, is employed to hop one step at a time. Methods for externally tracking the Scout are developed. A large number of real-world experiments are conducted and the results discussed.

Drug-induced modification of the system properties associated with spontaneous human electroencephalographic activity

Science.gov (United States)

Liley, David T.; Cadusch, Peter J.; Gray, Marcus; Nathan, Pradeep J.

2003-11-01

The benzodiazepine (BZ) class of minor tranquilizers are important modulators of the γ-amino butyric acid (GABAA)/BZ receptor complex that are well known to affect the spectral properties of spontaneous electroencephalographic activity. While it is experimentally well established that the BZs reduce total alpha band (8 13 Hz) power and increase total beta band (13 30 Hz) power, it is unclear what the physiological basis for this effect is. Based on a detailed theory of cortical electrorhythmogenesis it is conjectured that such an effect is explicable in terms of the modulation of GABAergic neurotransmission within locally connected populations of excitatory and inhibitory cortical neurons. Motivated by this theory, fixed order autoregressive moving average (ARMA) models were fitted to spontaneous eyes-closed electroencephalograms recorded from subjects before and approximately 2 h after the oral administration of a single 1 mg dose of the BZ alprazolam. Subsequent pole-zero analysis revealed that BZs significantly transform the dominant system pole such that its frequency and damping increase. Comparisons of ARMA derived power spectra with fast Fourier transform derived spectra indicate an enhanced ability to identify benzodiazepine induced electroencephalographic changes. This experimental result is in accord with the theoretical predictions implying that alprazolam enhances inhibition acting on inhibitory neurons more than inhibition acting on excitatory neurons. Further such a result is consistent with reported cortical neuronal distributions of the various GABAA receptor pharmacological subtypes. Therefore physiologically specified fixed order ARMA modeling is expected to become an important tool for the systematic investigation and modeling of a wide range of cortically acting compounds.

Glutamatergic and GABAergic TCA cycle and neurotransmitter cycling fluxes in different regions of mouse brain.

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Tiwari, Vivek; Ambadipudi, Susmitha; Patel, Anant B

2013-10-01

The (13)C nuclear magnetic resonance (NMR) studies together with the infusion of (13)C-labeled substrates in rats and humans have provided important insight into brain energy metabolism. In the present study, we have extended a three-compartment metabolic model in mouse to investigate glutamatergic and GABAergic tricarboxylic acid (TCA) cycle and neurotransmitter cycle fluxes across different regions of the brain. The (13)C turnover of amino acids from [1,6-(13)C2]glucose was monitored ex vivo using (1)H-[(13)C]-NMR spectroscopy. The astroglial glutamate pool size, one of the important parameters of the model, was estimated by a short infusion of [2-(13)C]acetate. The ratio Vcyc/VTCA was calculated from the steady-state acetate experiment. The (13)C turnover curves of [4-(13)C]/[3-(13)C]glutamate, [4-(13)C]glutamine, [2-(13)C]/[3-(13)C]GABA, and [3-(13)C]aspartate from [1,6-(13)C2]glucose were analyzed using a three-compartment metabolic model to estimate the rates of the TCA cycle and neurotransmitter cycle associated with glutamatergic and GABAergic neurons. The glutamatergic TCA cycle rate was found to be highest in the cerebral cortex (0.91 ± 0.05 μmol/g per minute) and least in the hippocampal region (0.64 ± 0.07 μmol/g per minute) of the mouse brain. In contrast, the GABAergic TCA cycle flux was found to be highest in the thalamus-hypothalamus (0.28 ± 0.01 μmol/g per minute) and least in the cerebral cortex (0.24 ± 0.02 μmol/g per minute). These findings indicate that the energetics of excitatory and inhibitory function is distinct across the mouse brain.

Critical Roles of the Direct GABAergic Pallido-cortical Pathway in Controlling Absence Seizures

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Li, Min; Ma, Tao; Wu, Shengdun; Ma, Jingling; Cui, Yan; Xia, Yang; Xu, Peng; Yao, Dezhong

2015-01-01

The basal ganglia (BG), serving as an intermediate bridge between the cerebral cortex and thalamus, are believed to play crucial roles in controlling absence seizure activities generated by the pathological corticothalamic system. Inspired by recent experiments, here we systematically investigate the contribution of a novel identified GABAergic pallido-cortical pathway, projecting from the globus pallidus externa (GPe) in the BG to the cerebral cortex, to the control of absence seizures. By computational modelling, we find that both increasing the activation of GPe neurons and enhancing the coupling strength of the inhibitory pallido-cortical pathway can suppress the bilaterally synchronous 2–4 Hz spike and wave discharges (SWDs) during absence seizures. Appropriate tuning of several GPe-related pathways may also trigger the SWD suppression, through modulating the activation level of GPe neurons. Furthermore, we show that the previously discovered bidirectional control of absence seizures due to the competition between other two BG output pathways also exists in our established model. Importantly, such bidirectional control is shaped by the coupling strength of this direct GABAergic pallido-cortical pathway. Our work suggests that the novel identified pallido-cortical pathway has a functional role in controlling absence seizures and the presented results might provide testable hypotheses for future experimental studies. PMID:26496656

Central Hypothyroidism in Miniature Schnauzers

NARCIS (Netherlands)

Voorbij, Annemarie M W Y; Leegwater, Peter A J; Buijtels, Jenny J C W M; Daminet, Sylvie; Kooistra, Hans S

2016-01-01

BACKGROUND: Primary hypothyroidism is a common endocrinopathy in dogs. In contrast, central hypothyroidism is rare in this species. OBJECTIVES: The objective of this article is to describe the occurrence and clinical presentation of central hypothyroidism in Miniature Schnauzers. Additionally, the

Short-term mastication after weaning upregulates GABAergic signalling and reduces dendritic spine in thalamus.

Science.gov (United States)

Ogawa, Mana; Nagai, Toshitada; Saito, Yoshikazu; Miyaguchi, Hitonari; Kumakura, Kei; Abe, Keiko; Asakura, Tomiko

2018-04-06

Mastication enhances brain function and mental health, but little is known about the molecular mechanisms underlying the effects of mastication on neural development in early childhood. Therefore, we analysed the gene expression in juvenile neural circuits in rats fed with a soft or chow diet immediately after weaning. We observed that the gene expression patterns in the thalamus varied depending on the diet. Furthermore, gene ontology analysis revealed that two terms were significantly enhanced: chemical synaptic transmission and positive regulation of dendritic spine morphogenesis. With respect to chemical synaptic transmission, glutamate decarboxylase and GABA receptors were upregulated in the chow diet group. The related genes, including vesicular GABA transporter, were also upregulated, suggesting that mastication activates GABAergic signalling. With respect to dendritic spine morphogenesis, Ingenuity Pathway Analysis predicted fewer extension of neurites and neurons and fewer number of branches in the chow diet group. The numbers of spines in the ventral posterolateral and posteromedial regions were significantly decreased. These results suggest that mastication in the early developing period upregulates GABAergic signalling genes, with a decrease of spines in the thalamus. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Passiflora incarnata attenuation of neuropathic allodynia and vulvodynia apropos GABA-ergic and opioidergic antinociceptive and behavioural mechanisms.

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Aman, Urooj; Subhan, Fazal; Shahid, Muhammad; Akbar, Shehla; Ahmad, Nisar; Ali, Gowhar; Fawad, Khwaja; Sewell, Robert D E

2016-02-24

Passiflora incarnata is widely used as an anxiolytic and sedative due to its putative GABAergic properties. Passiflora incarnata L. methanolic extract (PI-ME) was evaluated in an animal model of streptozotocin-induced diabetic neuropathic allodynia and vulvodynia in rats along with antinociceptive, anxiolytic and sedative activities in mice in order to examine possible underlying mechanisms. PI-ME was tested preliminary for qualitative phytochemical analysis and then quantitatively by proximate and GC-MS analysis. The antinociceptive property was evaluated using the abdominal constriction assay and hot plate test. The anxiolytic activity was performed in a stair case model and sedative activity in an open field test. The antagonistic activities were evaluated using naloxone and/or pentylenetetrazole (PTZ). PI-ME was evaluated for prospective anti-allodynic and anti-vulvodynic properties in a rat model of streptozotocin induced neuropathic pain using the static and dynamic testing paradigms of mechanical allodynia and vulvodynia. GC-MS analysis revealed that PI-ME contained predominant quantities of oleamide (9-octadecenamide), palmitic acid (hexadecanoic acid) and 3-hydroxy-dodecanoic acid, among other active constituents. In the abdominal constriction assay and hot plate test, PI-ME produced dose dependant, naloxone and pentylenetetrazole reversible antinociception suggesting an involvement of opioidergic and GABAergic mechanisms. In the stair case test, PI-ME at 200 mg/kg increased the number of steps climbed while at 600 mg/kg a significant decrease was observed. The rearing incidence was diminished by PI-ME at all tested doses and in the open field test, PI-ME decreased locomotor activity to an extent that was analagous to diazepam. The effects of PI-ME were antagonized by PTZ in both the staircase and open field tests implicating GABAergic mechanisms in its anxiolytic and sedative activities. In the streptozotocin-induced neuropathic nociceptive model, PI

Small is beautiful: features of the smallest insects and limits to miniaturization.

Science.gov (United States)

Polilov, Alexey A

2015-01-07

Miniaturization leads to considerable reorganization of structures in insects, affecting almost all organs and tissues. In the smallest insects, comparable in size to unicellular organisms, modifications arise not only at the level of organs, but also at the cellular level. Miniaturization is accompanied by allometric changes in many organ systems. The consequences of miniaturization displayed by different insect taxa include both common and unique changes. Because the smallest insects are among the smallest metazoans and have the most complex organization among organisms of the same size, their peculiar structural features and the factors that limit their miniaturization are of considerable theoretical interest to general biology.

Structure Design and Performance Analysis of High-Speed Miniature Ball Bearing

Science.gov (United States)

Li, Songsheng; Zhang, Guoye; Chen, Bin; Shen, Yuan

2017-07-01

The working performances of miniature ball bearings are obviously affected by its’ geometric structure parameters. In this paper, quasi-static analysis theory is applied in the design of miniature ball bearings. Firstly, it is studied the influence of geometry structure, preload and rotating speed on the dynamic performance of bearing. Secondly, bearing dynamic characteristics are analyzed which include the bearing stiffness and Spin to roll Ratio. Lastly, the contact stress and bearing life are calculated. The results indicate that structure parameters play an importance role in bearing’s dynamic performances. Miniature ball bearings which have lager ball number, bigger ball diameter and smaller inner race groove radius can get better performances while velocity and preload have great impact on the bearing life. So that parameters of miniature bearing should be chosen cautiously.

Using Miniature Landforms in Teaching Geomorphology.

Science.gov (United States)

Petersen, James F.

1986-01-01

This paper explores the uses of true landform miniatures and small-scale analogues and suggests ways to teach geomorphological concepts using small-scale relief features as illustrative examples. (JDH)

Age-dependent, lasting effects of methylphenidate on the GABAergic system of ADHD patients

Directory of Open Access Journals (Sweden)

Michelle M. Solleveld

2017-01-01

First stimulant exposure at a young age is thus associated with lower baseline levels of GABA+ and increased responsivity in adulthood. This effect could not be found in patients that started treatment at an adult age. Hence, while adult stimulant treatment seems to exert no major effects on GABA+ levels in the mPFC, MPH may induce long-lasting alterations in the adult mPFC GABAergic system when treatment was started at a young age.

Miniaturization of Multiple-Layer Folded Patch Antennas

DEFF Research Database (Denmark)

Zhang, Jiaying; Breinbjerg, Olav

2009-01-01

A new folded patch antenna with multiple layers was developed in this paper, by folding the patch in a proper way, and a highly miniaturized antenna can be realized. The multiple layer patch with 4-layer and 6-layer are designed and evaluated at 2.4 GHz, 915 MHz, and 415 MHz respectively. Then a 4...... layer patch is fabricated and measured to validate the design method. The theoretical analysis, design and simulations, fabrications, as well as the measurements are presented in this paper. All the results show that the folded patch antenna is a good candidate in making a highly miniaturized compact...

Use of miniature tensile specimen and video extensometer for measurement of mechanical properties

International Nuclear Information System (INIS)

Kumar, Kundan; Pooleery, Arun; Madhusoodanan, K.

2014-08-01

Miniaturisation of the tensile test specimen below the sub-size level poses various challenges, such as conformity of specimen to various acceptance criteria as per standard test specimen, aspect ratio, minimum number of grains required in a gauge cross-section, fabrication for uniformity in metrological values, etc. Apart from these, measurement of strain over a very limited available space on the test specimen is another practical challenge. Despite these limitations, miniature specimen testing is increasingly being used worldwide these days. The driving forces behind increasing use of miniature test techniques are new material development, assuring fitness of component after in-service-inspection, low dose of radiation exposure due to smaller dimensions of test specimens etc. However, the evaluation of mechanical properties from a miniature tensile test has a greater advantage over the other miniature novel test techniques, such as small punch test, ABI, miniature fatigue and impact tests etc., as it is a direct method of measurement of mechanical properties. This report covers various aspects of miniature tensile test methodologies, which include geometrical design of specimen having gauge length of 3-5 mm, fabrication, development of special fixtures for gripping the test specimens, and use of optical method for strain measurement. The geometrical design of the specimen and its behaviour over application of tensile load has been established using FEM analysis. A good agreement between conventional and miniature test results exemplifies the potential of the miniature tensile test technique. (author)

Preface Miniaturization and Mass Spectrometry

NARCIS (Netherlands)

Unknown, [Unknown; le Gac, Severine; le Gac, S.; van den Berg, Albert; van den Berg, A.

2009-01-01

Miniaturization and Mass Spectrometry illustrates this trend and focuses on one particular analysis technique, mass spectrometry whose popularity has "dramatically" increased in the last two decades with the explosion of the field of biological analysis and the development of two "soft" ionization

Miniaturized inertial impactor for personal airborne particulate monitoring: Prototyping

Science.gov (United States)

Pasini, Silvia; Bianchi, Elena; Dubini, Gabriele; Cortelezzi, Luca

2017-11-01

Computational fluid dynamic (CFD) simulations allowed us to conceive and design a miniaturized inertial impactor able to collect fine airborne particulate matter (PM10, PM2.5 and PM1). We created, by 3D printing, a prototype of the impactor. We first performed a set of experiments by applying a suction pump to the outlets and sampling the airborne particulate of our laboratory. The analysis of the slide showed a collection of a large number of particles, spanning a wide range of sizes, organized in a narrow band located below the exit of the nozzle. In order to show that our miniaturized inertial impactor can be truly used as a personal air-quality monitor, we performed a second set of experiments where the suction needed to produce the airflow through the impactor is generated by a human being inhaling through the outlets of the prototype. To guarantee a number of particles sufficient to perform a quantitative characterization, we collected particles performing ten consecutive deep inhalations. Finally, the potentiality for realistic applications of our miniaturized inertial impactor used in combination with a miniaturized single-particle detector will be discussed. CARIPLO Fundation - project MINUTE (Grant No. 2011-2118).

Clonidine, an alpha2-receptor agonist, diminishes GABAergic neurotransmission to cardiac vagal neurons in the nucleus ambiguus.

Science.gov (United States)

Philbin, Kerry E; Bateman, Ryan J; Mendelowitz, David

2010-08-06

In hypertension, there is an autonomic imbalance in which sympathetic activity dominates over parasympathetic control. Parasympathetic activity to the heart originates from cardiac vagal neurons located in the nucleus ambiguus. Presympathetic neurons that project to sympathetic neurons in the spinal cord are located in the ventral brainstem in close proximity to cardiac vagal neurons, and many of these presympathetic neurons are catecholaminergic. In addition to their projection to the spinal cord, many of these presympathetic neurons have axon collaterals that arborize into neighboring cardiorespiratory locations and likely release norepinephrine onto nearby neurons. Activation of alpha(2)-adrenergic receptors in the central nervous system evokes a diverse range of physiological effects, including reducing blood pressure. This study tests whether clonidine, an alpha(2)-adrenergic receptor agonist, alters excitatory glutamatergic, and/or inhibitory GABAergic or glycinergic synaptic neurotransmission to cardiac vagal neurons in the nucleus ambiguus. Cardiac vagal neurons were identified in an in vitro brainstem slice preparation, and synaptic events were recording using whole cell voltage clamp methodologies. Clonidine significantly inhibited GABAergic neurotransmission but had no effect on glycinergic or glutamatergic pathways to cardiac vagal neurons. This diminished inhibitory GABAergic neurotransmission to cardiac vagal neurons would increase parasympathetic activity to the heart, decreasing heart rate and blood pressure. The results presented here provide a cellular substrate for the clinical use of clonidine as a treatment for hypertension as well as a role in alleviating posttraumatic stress disorder by evoking an increase in parasympathetic cardiac vagal activity, and a decrease in heart rate and blood pressure. Copyright 2010 Elsevier B.V. All rights reserved.

Distinct GABAergic targets of feedforward and feedback connections between lower and higher areas of rat visual cortex.

Science.gov (United States)

Gonchar, Yuri; Burkhalter, Andreas

2003-11-26

Processing of visual information is performed in different cortical areas that are interconnected by feedforward (FF) and feedback (FB) pathways. Although FF and FB inputs are excitatory, their influences on pyramidal neurons also depend on the outputs of GABAergic neurons, which receive FF and FB inputs. Rat visual cortex contains at least three different families of GABAergic neurons that express parvalbumin (PV), calretinin (CR), and somatostatin (SOM) (Gonchar and Burkhalter, 1997). To examine whether pathway-specific inhibition (Shao and Burkhalter, 1996) is attributable to distinct connections with GABAergic neurons, we traced FF and FB inputs to PV, CR, and SOM neurons in layers 1-2/3 of area 17 and the secondary lateromedial area in rat visual cortex. We found that in layer 2/3 maximally 2% of FF and FB inputs go to CR and SOM neurons. This contrasts with 12-13% of FF and FB inputs onto layer 2/3 PV neurons. Unlike inputs to layer 2/3, connections to layer 1, which contains CR but lacks SOM and PV somata, are pathway-specific: 21% of FB inputs go to CR neurons, whereas FF inputs to layer 1 and its CR neurons are absent. These findings suggest that FF and FB influences on layer 2/3 pyramidal neurons mainly involve disynaptic connections via PV neurons that control the spike outputs to axons and proximal dendrites. Unlike FF input, FB input in addition makes a disynaptic link via CR neurons, which may influence the excitability of distal pyramidal cell dendrites in layer 1.

Corticospinal tract insult alters GABAergic circuitry in the mammalian spinal cord

Directory of Open Access Journals (Sweden)

Jeffrey B. Russ

2013-09-01

Full Text Available During perinatal development, corticospinal tract (CST projections into the spinal cord help refine spinal circuitry. Although the normal developmental processes that are controlled by the arrival of corticospinal input are becoming clear, little is known about how perinatal cortical damage impacts specific aspects of spinal circuit development, particularly the inhibitory microcircuitry that regulates spinal reflex circuits. In this study, we sought to determine how ischemic cortical damage impacts the synaptic attributes of a well-characterized population of inhibitory, GABAergic interneurons, called GABApre neurons, which modulates the efficiency of proprioceptive sensory terminals in the sensorimotor reflex circuit. We found that putative GABApre interneurons receive CST input and, using an established mouse model of perinatal stroke, that cortical ischemic injury results in a reduction of CST density within the intermediate region of the spinal cord, where these interneurons reside. Importantly, CST alterations were restricted to the side contralateral to the injury. Within the synaptic terminals of the GABApre interneurons, we observed a dramatic upregulation of the 65-isoform of the GABA synthetic enzyme glutamic acid decarboxylase (GAD65. In accordance with the CST density reduction, GAD65 was elevated on the side of the spinal cord contralateral to cortical injury. This effect was not seen for other GABApre synaptic markers or in animals that received sham surgery. Our data reveal a novel effect of perinatal stroke that involves severe deficits in the architecture of descending spinal pathways, which in turn appear to promote molecular alterations in a specific spinal GABAergic circuit.

Calcium imaging of basal forebrain activity during innate and learned behaviors

Directory of Open Access Journals (Sweden)

Thomas Clarke Harrison

2016-05-01

Full Text Available The basal forebrain (BF plays crucial roles in arousal, attention, and memory, and its impairment is associated with a variety of cognitive deficits. The BF consists of cholinergic, GABAergic, and glutamatergic neurons. Electrical or optogenetic stimulation of BF cholinergic neurons enhances cortical processing and behavioral performance, but the natural activity of these cells during behavior is only beginning to be characterized. Even less is known about GABAergic and glutamatergic neurons. Here, we performed microendoscopic calcium imaging of BF neurons as mice engaged in spontaneous behaviors in their home cages (innate or performed a go/no-go auditory discrimination task (learned. Cholinergic neurons were consistently excited during movement, including running and licking, but GABAergic and glutamatergic neurons exhibited diverse responses. All cell types were activated by overt punishment, either inside or outside of the discrimination task. These findings reveal functional similarities and distinctions between BF cell types during both spontaneous and task-related behaviors.

Spontaneous mutation by mutagenic repair of spontaneous lesions in DNA

International Nuclear Information System (INIS)

Hastings, P.J.; Quah, S.-K.; Borstel, R.C. von

1976-01-01

It is stated that strains of yeast carrying mutations in many of the steps in pathways repairing radiation-induced damage to DNA have enhanced spontaneous mutation rates. Most strains isolated because they have enhanced spontaneous mutation carry mutations in DNA repair systems. This suggests that much spontaneous mutation arises by mutagenic repair of spontaneous lesions. (author)

46 CFR 52.25-5 - Miniature boilers (modifies PMB-1 through PMB-21).

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Miniature boilers (modifies PMB-1 through PMB-21). 52.25... ENGINEERING POWER BOILERS Other Boiler Types § 52.25-5 Miniature boilers (modifies PMB-1 through PMB-21). Miniature boilers must meet the applicable provisions in this part for the boiler type involved and the...

Development of fatigue life evaluation technique using miniature specimen

International Nuclear Information System (INIS)

Nogami, Shuhei; Nishimura, Arata; Fujiwara, Masaharu; Hisaka, Tomoaki

2012-01-01

To develop the fatigue life evaluation technique using miniature specimen, the investigation of the effect of specimen size and specimen shape on the fatigue life and the development of the fatigue testing machine, especially the extensometer, were carried out. The effect of specimen size on the fatigue life was almost negligible for the round-bar specimens. The shorter fatigue life at relatively low strain range conditions for the hourglass specimen that the standard specimen were observed. Therefore the miniature round-bar specimen was considered to be adequate for the fatigue life evaluation using small specimen. Several types of the extensometer system using a strain gauge and a laser has been developed for realizing the fatigue test of the miniature round-bar specimen at high temperature in vacuum. (author)

Glomerular Lesions in Proteinuric Miniature Schnauzer Dogs.

Science.gov (United States)

Furrow, E; Lees, G E; Brown, C A; Cianciolo, R E

2017-05-01

Miniature Schnauzer dogs are predisposed to idiopathic hypertriglyerceridemia, which increases risk for diseases such as pancreatitis and gallbladder mucocele. Recently, elevated triglyceride concentrations have been associated with proteinuria in this breed, although it is difficult to determine which abnormality is primary. Retrospective review of renal tissue from 27 proteinuric Miniature Schnauzers revealed that 20 dogs had ultrastructural evidence of osmophilic globules consistent with lipid in glomerular tufts. Seven of these dogs had lipid thromboemboli in glomerular capillary loops that distorted their shape and compressed circulating erythrocytes. Triglyceride concentrations were reported in 6 of these 7 dogs, and all were hypertriglyceridemic. In addition, glomerular lipidosis (defined as accumulation of foam cells within peripheral capillary loops) was identified in a single dog. The remaining 12 dogs had smaller amounts of lipid that could only be identified ultrastructurally. Neither signalment data nor clinicopathologic parameters (serum albumin, serum creatinine, urine protein-to-creatinine ratio, and blood pressure) differed among the various types of lipid lesions. During the time course of this study, all dogs diagnosed with glomerular lipid thromboemboli were Miniature Schnauzers, underscoring the importance of recognizing these clear spaces within capillary loops as lipid.

Miniature tensile test specimens for fusion reactor irradiation studies

International Nuclear Information System (INIS)

Klueh, R.L.

1985-01-01

Three miniature sheet-type tensile specimens and a miniature rod-type specimen are being used to determine irradiated tensile properties for alloy development for fusion reactors. The tensile properties of type 316 stainless steel were determined with these different specimens, and the results were compared. Reasonably good agreement was observed. However, there were differences that led to recommendations on which specimens are preferred. 4 references, 9 figures, 6 tables

Analysis of nonlinear elastic behavior in miniature pneumatic artificial muscles

Science.gov (United States)

Hocking, Erica G.; Wereley, Norman M.

2013-01-01

Pneumatic artificial muscles (PAMs) are well known for their excellent actuator characteristics, including high specific work, specific power, and power density. Recent research has focused on miniaturizing this pneumatic actuator technology in order to develop PAMs for use in small-scale mechanical systems, such as those found in robotic or aerospace applications. The first step in implementing these miniature PAMs was to design and characterize the actuator. To that end, this study presents the manufacturing process, experimental characterization, and analytical modeling of PAMs with millimeter-scale diameters. A fabrication method was developed to consistently produce low-cost, high performance, miniature PAMs using commercially available materials. The quasi-static behavior of these PAMs was determined through experimentation on a single actuator with an active length of 39.16 mm (1.54 in) and a diameter of 4.13 mm (0.1625 in). Testing revealed the PAM’s full evolution of force with displacement for operating pressures ranging from 207 to 552 kPa (30-80 psi in 10 psi increments), as well as the blocked force and free contraction at each pressure. Three key nonlinear phenomena were observed: nonlinear PAM stiffness, hysteresis of the force versus displacement response for a given pressure, and a pressure deadband. To address the analysis of the nonlinear response of these miniature PAMs, a nonlinear stress versus strain model, a hysteresis model, and a pressure bias are introduced into a previously developed force balance analysis. Parameters of these nonlinear model refinements are identified from the measured force versus displacement data. This improved nonlinear force balance model is shown to capture the full actuation behavior of the miniature PAMs at each operating pressure and reconstruct miniature PAM response with much more accuracy than previously possible.

Analysis of nonlinear elastic behavior in miniature pneumatic artificial muscles

International Nuclear Information System (INIS)

Hocking, Erica G; Wereley, Norman M

2013-01-01

Pneumatic artificial muscles (PAMs) are well known for their excellent actuator characteristics, including high specific work, specific power, and power density. Recent research has focused on miniaturizing this pneumatic actuator technology in order to develop PAMs for use in small-scale mechanical systems, such as those found in robotic or aerospace applications. The first step in implementing these miniature PAMs was to design and characterize the actuator. To that end, this study presents the manufacturing process, experimental characterization, and analytical modeling of PAMs with millimeter-scale diameters. A fabrication method was developed to consistently produce low-cost, high performance, miniature PAMs using commercially available materials. The quasi-static behavior of these PAMs was determined through experimentation on a single actuator with an active length of 39.16 mm (1.54 in) and a diameter of 4.13 mm (0.1625 in). Testing revealed the PAM’s full evolution of force with displacement for operating pressures ranging from 207 to 552 kPa (30–80 psi in 10 psi increments), as well as the blocked force and free contraction at each pressure. Three key nonlinear phenomena were observed: nonlinear PAM stiffness, hysteresis of the force versus displacement response for a given pressure, and a pressure deadband. To address the analysis of the nonlinear response of these miniature PAMs, a nonlinear stress versus strain model, a hysteresis model, and a pressure bias are introduced into a previously developed force balance analysis. Parameters of these nonlinear model refinements are identified from the measured force versus displacement data. This improved nonlinear force balance model is shown to capture the full actuation behavior of the miniature PAMs at each operating pressure and reconstruct miniature PAM response with much more accuracy than previously possible. (paper)

Miniature bread baking as a timesaving research approach and mathematical modeling of browning kinetics

NARCIS (Netherlands)

Zhang, Lu; Putranto, Aditya; Zhou, Weibiao; Boom, Remko M.; Schutyser, Maarten A.I.; Chen, Xiao Dong

2016-01-01

Miniature bread baking is presented as an economical and timesaving laboratory approach to study the baking process in the present work. Results indicate that the miniature bread baking is essentially analogical to the baking process of regular-sized bread: quality-related properties of miniature

Reelin secreted by GABAergic neurons regulates glutamate receptor homeostasis.

Directory of Open Access Journals (Sweden)

Cecilia Gonzalez Campo

Full Text Available BACKGROUND: Reelin is a large secreted protein of the extracellular matrix that has been proposed to participate to the etiology of schizophrenia. During development, reelin is crucial for the correct cytoarchitecture of laminated brain structures and is produced by a subset of neurons named Cajal-Retzius. After birth, most of these cells degenerate and reelin expression persists in postnatal and adult brain. The phenotype of neurons that bind secreted reelin and whether the continuous secretion of reelin is required for physiological functions at postnatal stages remain unknown. METHODOLOGY/PRINCIPAL FINDINGS: Combining immunocytochemical and pharmacological approaches, we first report that two distinct patterns of reelin expression are present in cultured hippocampal neurons. We show that in hippocampal cultures, reelin is secreted by GABAergic neurons displaying an intense reelin immunoreactivity (IR. We demonstrate that secreted reelin binds to receptors of the lipoprotein family on neurons with a punctate reelin IR. Secondly, using calcium imaging techniques, we examined the physiological consequences of reelin secretion blockade. Blocking protein secretion rapidly and reversibly changes the subunit composition of N-methyl-D-aspartate glutamate receptors (NMDARs to a predominance of NR2B-containing NMDARs. Addition of recombinant or endogenously secreted reelin rescues the effects of protein secretion blockade and reverts the fraction of NR2B-containing NMDARs to control levels. Therefore, the continuous secretion of reelin is necessary to control the subunit composition of NMDARs in hippocampal neurons. CONCLUSIONS/SIGNIFICANCE: Our data show that the heterogeneity of reelin immunoreactivity correlates with distinct functional populations: neurons synthesizing and secreting reelin and/or neurons binding reelin. Furthermore, we show that continuous reelin secretion is a strict requirement to maintain the composition of NMDARs. We propose

Miniaturization design and implementation of magnetic field coupled RFID antenna

Science.gov (United States)

Hu, Tiling

2013-03-01

The development of internet of things has brought new opportunities and challenges to the application of RFID tags. Moreover, the Miniaturization application trend of tags at present has become the mainstream of development. In this paper, the double-layer design is to reduce the size of HF antenna, and the magnetic null point of magnetic reconnection region between the RLC resonant circuit and the reader provides sufficient energy to the miniaturization of antenna. The calculated and experimental results show that the miniaturization of HF antennas can meet the reading and writing requirement of the international standard ISO/IEC14443 standard. The results of this paper may make a positive contribution to the applications of RFID technology.

Activity strengths of cortical glutamatergic and GABAergic neurons are correlated with transgenerational inheritance of learning ability.

Science.gov (United States)

Liu, Yulong; Ge, Rongjing; Zhao, Xin; Guo, Rui; Huang, Li; Zhao, Shidi; Guan, Sudong; Lu, Wei; Cui, Shan; Wang, Shirlene; Wang, Jin-Hui

2017-12-22

The capabilities of learning and memory in parents are presumably transmitted to their offsprings, in which genetic codes and epigenetic regulations are thought as molecular bases. As neural plasticity occurs during memory formation as cellular mechanism, we aim to examine the correlation of activity strengths at cortical glutamatergic and GABAergic neurons to the transgenerational inheritance of learning ability. In a mouse model of associative learning, paired whisker and odor stimulations led to odorant-induced whisker motion, whose onset appeared fast (high learning efficiency, HLE) or slow (low learning efficiency, LLE). HLE male and female mice, HLE female and LLE male mice as well as HLE male and LLE female mice were cross-mated to have their first generation of offsprings, filials (F1). The onset of odorant-induced whisker motion appeared a sequence of high-to-low efficiency in three groups of F1 mice that were from HLE male and female mice, HLE female and LLE male mice as well as HLE male and LLE female mice. Activities related to glutamatergic neurons in barrel cortices appeared a sequence of high-to-low strength in these F1 mice from HLE male and female mice, HLE female and LLE male mice as well as HLE male and LLE female mice. Activities related to GABAergic neurons in barrel cortices appeared a sequence of low-to-high strength in these F1 mice from HLE male and female mice, HLE female and LLE male mice as well as HLE male and LLE female mice. Neuronal activity strength was linearly correlated to learning efficiency among three groups. Thus, the coordinated activities at glutamatergic and GABAergic neurons may constitute the cellular basis for the transgenerational inheritance of learning ability.

Evaluation of the cationic trypsinogen gene for potential mutations in miniature schnauzers with pancreatitis.

Science.gov (United States)

Bishop, Micah A; Steiner, Jörg M; Moore, Lisa E; Williams, David A

2004-10-01

The purpose of this study was to evaluate the cationic trypsinogen gene in miniature schnauzers for possible mutations. Genetic mutations have been linked with hereditary pancreatitis in humans. Four miniature schnauzers were selected on the basis of a clinical history of pancreatitis. One healthy miniature schnauzer and 1 healthy mixed breed canine were enrolled as controls. DNA was extracted from these canines using a commercial kit. Primers were designed to amplify the entire canine cationic trypsinogen cDNA sequence. A polymerase chain reaction (PCR) was performed and products were purified and sequenced. All sequences were then compared. The healthy control canine, a healthy miniature schnauzer, and the 4 miniature schnauzers with pancreatitis showed identical sequences of the cationic trypsinogen gene to the published sequence. We conclude that, in contrast to humans with hereditary pancreatitis, mutations of the cationic trypsinogen gene do not play a major role in the genesis of pancreatitis in the miniature schnauzer.

Prenatal exposure to an NMDA receptor antagonist, MK-801 reduces density of parvalbumin-immunoreactive GABAergic neurons in the medial prefrontal cortex and enhances phencyclidine-induced hyperlocomotion but not behavioral sensitization to methamphetamine in postpubertal rats.

Science.gov (United States)

Abekawa, Tomohiro; Ito, Koki; Nakagawa, Shin; Koyama, Tsukasa

2007-06-01

Neurodevelopmental deficits of parvalbumin-immunoreactive gamma-aminobutyric acid (GABA)ergic interneurons in prefrontal cortex have been reported in schizophrenia. Glutamate influences the proliferation of this type of interneuron by an N-methyl-D-aspartate (NMDA)-receptor-mediated mechanism. The present study hypothesized that prenatal blockade of NMDA receptors would disrupt GABAergic neurodevelopment, resulting in differences in effects on behavioral responses to a noncompetitive NMDA antagonist, phencyclidine (PCP), and a dopamine releaser, methamphetamine (METH). GABAergic neurons were immunohistochemically stained with parvalbumin antibody. Psychostimulant-induced hyperlocomotion was measured using an infrared sensor. Prenatal exposure (E15-E18) to the NMDA receptor antagonist MK-801 reduced the density of parvalbumin-immunoreactive neurons in rat medial prefrontal cortex on postnatal day 63 (P63) and enhanced PCP-induced hyperlocomotion but not the acute effects of METH on P63 or the development of behavioral sensitization. Prenatal exposure to MK-801 reduced the number of parvalbumin-immunoreactive neurons even on postnatal day 35 (P35) and did not enhance PCP-induced hyperlocomotion, the acute effects of METH on P35, or the development of behavioral sensitization to METH. These findings suggest that prenatal blockade of NMDA receptors disrupts GABAergic neurodevelopment in medial prefrontal cortex, and that this disruption of GABAergic development may be related to the enhancement of the locomotion-inducing effect of PCP in postpubertal but not juvenile offspring. GABAergic deficit is unrelated to the effects of METH. This GABAergic neurodevelopmental disruption and the enhanced PCP-induced hyperlocomotion in adult offspring prenatally exposed to MK-801 may prove useful as a new model of the neurodevelopmental process of pathogenesis of treatment-resistant schizophrenia via an NMDA-receptor-mediated hypoglutamatergic mechanism.

Perineuronal Net Protein Neurocan Inhibits NCAM/EphA3 Repellent Signaling in GABAergic Interneurons.

Science.gov (United States)

Sullivan, Chelsea S; Gotthard, Ingo; Wyatt, Elliott V; Bongu, Srihita; Mohan, Vishwa; Weinberg, Richard J; Maness, Patricia F

2018-04-18

Perineuronal nets (PNNs) are implicated in closure of critical periods of synaptic plasticity in the brain, but the molecular mechanisms by which PNNs regulate synapse development are obscure. A receptor complex of NCAM and EphA3 mediates postnatal remodeling of inhibitory perisomatic synapses of GABAergic interneurons onto pyramidal cells in the mouse frontal cortex necessary for excitatory/inhibitory balance. Here it is shown that enzymatic removal of PNN glycosaminoglycan chains decreased the density of GABAergic perisomatic synapses in mouse organotypic cortical slice cultures. Neurocan, a key component of PNNs, was expressed in postnatal frontal cortex in apposition to perisomatic synapses of parvalbumin-positive interneurons. Polysialylated NCAM (PSA-NCAM), which is required for ephrin-dependent synapse remodeling, bound less efficiently to neurocan than mature, non-PSA-NCAM. Neurocan bound the non-polysialylated form of NCAM at the EphA3 binding site within the immunoglobulin-2 domain. Neurocan inhibited NCAM/EphA3 association, membrane clustering of NCAM/EphA3 in cortical interneuron axons, EphA3 kinase activation, and ephrin-A5-induced growth cone collapse. These studies delineate a novel mechanism wherein neurocan inhibits NCAM/EphA3 signaling and axonal repulsion, which may terminate postnatal remodeling of interneuron axons to stabilize perisomatic synapses in vivo.

A very large number of GABAergic neurons are activated in the tuberal hypothalamus during paradoxical (REM sleep hypersomnia.

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Emilie Sapin

Full Text Available We recently discovered, using Fos immunostaining, that the tuberal and mammillary hypothalamus contain a massive population of neurons specifically activated during paradoxical sleep (PS hypersomnia. We further showed that some of the activated neurons of the tuberal hypothalamus express the melanin concentrating hormone (MCH neuropeptide and that icv injection of MCH induces a strong increase in PS quantity. However, the chemical nature of the majority of the neurons activated during PS had not been characterized. To determine whether these neurons are GABAergic, we combined in situ hybridization of GAD(67 mRNA with immunohistochemical detection of Fos in control, PS deprived and PS hypersomniac rats. We found that 74% of the very large population of Fos-labeled neurons located in the tuberal hypothalamus after PS hypersomnia were GAD-positive. We further demonstrated combining MCH immunohistochemistry and GAD(67in situ hybridization that 85% of the MCH neurons were also GAD-positive. Finally, based on the number of Fos-ir/GAD(+, Fos-ir/MCH(+, and GAD(+/MCH(+ double-labeled neurons counted from three sets of double-staining, we uncovered that around 80% of the large number of the Fos-ir/GAD(+ neurons located in the tuberal hypothalamus after PS hypersomnia do not contain MCH. Based on these and previous results, we propose that the non-MCH Fos/GABAergic neuronal population could be involved in PS induction and maintenance while the Fos/MCH/GABAergic neurons could be involved in the homeostatic regulation of PS. Further investigations will be needed to corroborate this original hypothesis.

Trajectory of the main GABAergic interneuron populations from early development to old age in the rat primary auditory cortex

Directory of Open Access Journals (Sweden)

Lydia eOuellet

2014-06-01

Full Text Available In both humans and rodents, decline in cognitive function is a hallmark of the aging process, the basis for this decrease has yet to be fully characterized. However, using aged rodent models, deficits in auditory processing have been associated with significant decreases in inhibitory signaling attributed to a loss of GABAergic interneurons. Not only are these interneurons crucial for pattern detection and other large-scale population dynamics, but they have also been linked to mechanisms mediating plasticity and learning, making them a prime candidate for study and modelling of modifications to cortical communication pathways in neurodegenerative diseases. Using the rat primary auditory cortex (A1 as a model, we probed the known markers of GABAergic interneurons with immunohistological methods, using antibodies against gamma aminobutyric acid (GABA, parvalbumin (PV, somatostatin (SOM, calretinin (CR, vasoactive intestinal peptide (VIP, choline acetyltransferase (ChAT, neuropeptide Y (NPY and cholecystokinin (CCK to document the changes observed in interneuron populations across the rat’s lifespan. This analysis provided strong evidence that several but not all GABAergic neurons were affected by the aging process, showing most dramatic changes in expression of parvalbumin (PV and somatostatin (SOM expression. With this evidence, we show how understanding these trajectories of cell counts may be factored into a simple model to quantify changes in inhibitory signalling across the course of life, which may be applied as a framework for creating more advanced simulations of interneuronal implication in normal cerebral processing, normal aging, or pathological processes.

Laser direct marking applied to rasterizing miniature Data Matrix Code on aluminum alloy

Science.gov (United States)

Li, Xia-Shuang; He, Wei-Ping; Lei, Lei; Wang, Jian; Guo, Gai-Fang; Zhang, Teng-Yun; Yue, Ting

2016-03-01

Precise miniaturization of 2D Data Matrix (DM) Codes on Aluminum alloy formed by raster mode laser direct part marking is demonstrated. The characteristic edge over-burn effects, which render vector mode laser direct part marking inadequate for producing precise and readable miniature codes, are minimized with raster mode laser marking. To obtain the control mechanism for the contrast and print growth of miniature DM code by raster laser marking process, the temperature field model of long pulse laser interaction with material is established. From the experimental results, laser average power and Q frequency have an important effect on the contrast and print growth of miniature DM code, and the threshold of laser average power and Q frequency for an identifiable miniature DM code are respectively 3.6 W and 110 kHz, which matches the model well within normal operating conditions. In addition, the empirical model of correlation occurring between laser marking parameters and module size is also obtained, and the optimal processing parameter values for an identifiable miniature DM code of different but certain data size are given. It is also found that an increase of the repeat scanning number effectively improves the surface finish of bore, the appearance consistency of modules, which has benefit to reading. The reading quality of miniature DM code is greatly improved using ultrasonic cleaning in water by avoiding the interference of color speckles surrounding modules.

Aesthetics of Islamic Miniature Art During the Periods of Safavid and ...

African Journals Online (AJOL)

Islamic art represents the spiritual and physical aspects in the lives of Muslims. Meaningful beauty in Islamic art expresses Islamic aesthetics. Islamic aesthetics is the connection between beauty and the sacred. The article is devoted to the Islamic art and miniature paintings of Timurid and Safavid periods in Iran. Miniature ...

Airtight miniaturized chromatography: a safer method for radiopharmaceutical quality control

International Nuclear Information System (INIS)

Coupal, J.J.; Shih, W.J.; Ryo, U.Y.

1988-01-01

Miniaturized chromatography is widely used for quality control of radiopharmaceuticals. Recently, published chromatography procedures have illustrated or described chromatography chambers open to the air in use, suggesting that volatile toxic mobile phases are harmless to people in the vicinity. The authors describe the results of their search for an inexpensive closed chromatography chamber that can be used to derive safely the benefits from conventional miniaturized chromatography

Low-power, miniature {sup 171}Yb ion clock using an ultra-small vacuum package

Energy Technology Data Exchange (ETDEWEB)

Jau, Y.-Y.; Schwindt, P. D. D. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Partner, H. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Center for Quantum Information and Control (CQuIC), Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Prestage, J. D.; Kellogg, J. R.; Yu, N. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

2012-12-17

We report a demonstration of a very small microwave atomic clock using the 12.6 GHz hyperfine transition of the trapped {sup 171}Yb ions inside a miniature, completely sealed-off 3 cm{sup 3} ion-trap vacuum package. In the ion clock system, all of the components are highly miniaturized with low power consumption except the 369 nm optical pumping laser still under development for miniaturization. The entire clock, including the control electronics, consumes <300 mW. The fractional frequency instability of the miniature Yb{sup +} clock reaches the 10{sup -14} range after a few days of integration.

High Performance Miniature Bandpass Filters, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This proposal is submitted for developing low impedance, miniature bandpass RF frequency filter via MEMS technique, in applications of SMAP, Aquarius follow-on,...

A Spectral Reconstruction Algorithm of Miniature Spectrometer Based on Sparse Optimization and Dictionary Learning.

Science.gov (United States)

Zhang, Shang; Dong, Yuhan; Fu, Hongyan; Huang, Shao-Lun; Zhang, Lin

2018-02-22

The miniaturization of spectrometer can broaden the application area of spectrometry, which has huge academic and industrial value. Among various miniaturization approaches, filter-based miniaturization is a promising implementation by utilizing broadband filters with distinct transmission functions. Mathematically, filter-based spectral reconstruction can be modeled as solving a system of linear equations. In this paper, we propose an algorithm of spectral reconstruction based on sparse optimization and dictionary learning. To verify the feasibility of the reconstruction algorithm, we design and implement a simple prototype of a filter-based miniature spectrometer. The experimental results demonstrate that sparse optimization is well applicable to spectral reconstruction whether the spectra are directly sparse or not. As for the non-directly sparse spectra, their sparsity can be enhanced by dictionary learning. In conclusion, the proposed approach has a bright application prospect in fabricating a practical miniature spectrometer.

Tensile and Creep Testing of Sanicro 25 Using Miniature Specimens

Science.gov (United States)

Dymáček, Petr; Jarý, Milan; Dobeš, Ferdinand; Kloc, Luboš

2018-01-01

Tensile and creep properties of new austenitic steel Sanicro 25 at room temperature and operating temperature 700 °C were investigated by testing on miniature specimens. The results were correlated with testing on conventional specimens. Very good agreement of results was obtained, namely in yield and ultimate strength, as well as short-term creep properties. Although the creep rupture time was found to be systematically shorter and creep ductility lower in the miniature test, the minimum creep rates were comparable. The analysis of the fracture surfaces revealed similar ductile fracture morphology for both specimen geometries. One exception was found in a small area near the miniature specimen edge that was cut by electro discharge machining, where an influence of the steel fracture behavior at elevated temperature was identified. PMID:29337867

Tensile and Creep Testing of Sanicro 25 Using Miniature Specimens.

Science.gov (United States)

Dymáček, Petr; Jarý, Milan; Dobeš, Ferdinand; Kloc, Luboš

2018-01-16

Tensile and creep properties of new austenitic steel Sanicro 25 at room temperature and operating temperature 700 °C were investigated by testing on miniature specimens. The results were correlated with testing on conventional specimens. Very good agreement of results was obtained, namely in yield and ultimate strength, as well as short-term creep properties. Although the creep rupture time was found to be systematically shorter and creep ductility lower in the miniature test, the minimum creep rates were comparable. The analysis of the fracture surfaces revealed similar ductile fracture morphology for both specimen geometries. One exception was found in a small area near the miniature specimen edge that was cut by electro discharge machining, where an influence of the steel fracture behavior at elevated temperature was identified.

Miniature specimen technology for postirradiation fatigue crack growth testing

International Nuclear Information System (INIS)

Mervyn, D.A.; Ermi, A.M.

1979-01-01

Current magnetic fusion reactor design concepts require that the fatigue behavior of candidate first wall materials be characterized. Fatigue crack growth may, in fact, be the design limiting factor in these cyclic reactor concepts given the inevitable presence of crack-like flaws in fabricated sheet structures. Miniature specimen technology has been developed to provide the large data base necessary to characterize irradiation effects on the fatigue crack growth behavior. An electrical potential method of measuring crack growth rates is employed on miniature center-cracked-tension specimens (1.27 cm x 2.54 cm x 0.061 cm). Results of a baseline study on 20% cold-worked 316 stainless steel, which was tested in an in-cell prototypic fatigue machine, are presented. The miniature fatigue machine is designed for low cost, on-line, real time testing of irradiated fusion candidate alloys. It will enable large scale characterization and development of candidate first wall alloys

Narrative Metamorphosis Through Images: The Case of Opening Miniatures in the Estoire del

Directory of Open Access Journals (Sweden)

Miha Zor

2015-12-01

Full Text Available The article deals with pictorial metamorphosis in the opening pages of two early 14th-century manuscripts of the Estoire del saint Graal. Firstly, the episodes depicted are analysed iconographically and formally. Secondly, it explores how pictorial narrative is established in the multi-compartmentalised miniature, that is how the images are linked internally in order to convey a narrative that has its beginning and its ending. Thirdly, it is shown how the images in the opening miniature communicate with other miniatures in the manuscript and how the course of interpretation, signaled by the opening miniature, is succeeded and confirmed by the selection of episodes which are subsequently depicted, as well as by the way in which the episodes depicted are pictorially interpreted.

Electrical and chemical transmission between striatal GABAergic output neurones in rat brain slices

Science.gov (United States)

Venance, Laurent; Glowinski, Jacques; Giaume, Christian

2004-01-01

Basal ganglia are interconnected subcortical nuclei, connected to the thalamus and all cortical areas involved in sensory motor control, limbic functions and cognition. The striatal output neurones (SONs), the major striatal population, are believed to act as detectors and integrators of distributed patterns of cerebral cortex inputs. Despite the key role of SONs in cortico-striatal information processing, little is known about their local interactions. Here, we report the existence and characterization of electrical and GABAergic transmission between SONs in rat brain slices. Tracer coupling (biocytin) incidence was high during the first two postnatal weeks and then decreased (postnatal days (P) 5–25, 60%; P25–30, 29%; n = 61). Electrical coupling was observed between 27% of SON pairs (coupling coefficient: 3.1 ± 0.3%, n = 89 at P15) and as shown by single-cell RT-PCR, several connexin (Cx) mRNAs were found to be expressed (Cx31.1, Cx32, Cx36 and Cx47). GABAergic synaptic transmission (abolished by bicuculline, a GABAA receptor antagonist) observed in 19% of SON pairs (n = 62) was reliable (mean failure rate of 6 ± 3%), precise (variation coefficient of latency, 0.06), strong (IPSC amplitudes of 38 ± 12 pA) and unidirectional. Interestingly, electrical and chemical transmission were mutually exclusive. These results suggest that preferential networks of electrically and chemically connected SONs, might be involved in the channelling of cortico-basal ganglia information processing. PMID:15235091

Essential Oils and Their Constituents Targeting the GABAergic System and Sodium Channels as Treatment of Neurological Diseases

Directory of Open Access Journals (Sweden)

Ze-Jun Wang

2018-05-01

Full Text Available Essential oils and the constituents in them exhibit different pharmacological activities, such as antinociceptive, anxiolytic-like, and anticonvulsant effects. They are widely applied as a complementary therapy for people with anxiety, insomnia, convulsion, pain, and cognitive deficit symptoms through inhalation, oral administration, and aromatherapy. Recent studies show that essential oils are emerging as a promising source for modulation of the GABAergic system and sodium ion channels. This review summarizes the recent findings regarding the pharmacological properties of essential oils and compounds from the oils and the mechanisms underlying their effects. Specifically, the review focuses on the essential oils and their constituents targeting the GABAergic system and sodium channels, and their antinociceptive, anxiolytic, and anticonvulsant properties. Some constituents target transient receptor potential (TRP channels to exert analgesic effects. Some components could interact with multiple therapeutic target proteins, for example, inhibit the function of sodium channels and, at the same time, activate GABAA receptors. The review concentrates on perspective compounds that could be better candidates for new drug development in the control of pain and anxiety syndromes.

Miniature and micro mass spectrometry for nanoscale sensing applications

International Nuclear Information System (INIS)

Taylor, S; France, N

2009-01-01

In recent years the use of miniature and/or microscale versions of the more popular mass spectrometers have been realised. This has led to the development of portable analytical devices for a range of 'in the field' sensing applications in aerospace, environmental monitoring, medical diagnosis and process control. In this paper the principles underpinning the development of miniature quadrupole mass spectrometers are reviewed. Two different microfabrication methods are compared with a conventional QMS used for residual gas analysis in the range 1-100 Da.

EMC, RF, and Antenna Systems in Miniature Electronic Devices

DEFF Research Database (Denmark)

Ruaro, Andrea

Advanced techniques for the control of electromagnetic interference (EMI) and for the optimization of the electromagnetic compatibility (EMC) performance has been developed under the constraints typical of miniature electronic devices (MED). The electromagnetic coexistence of multiple systems....... The structure allows for effective suppression of radiation from the MED, while taking into consideration the integration and miniaturization aspects. To increase the sensitivity of the system, a compact LNA suitable for on-body applications has been developed. The LNA allows for an increase in the overall...

A Spectral Reconstruction Algorithm of Miniature Spectrometer Based on Sparse Optimization and Dictionary Learning

Science.gov (United States)

Zhang, Shang; Fu, Hongyan; Huang, Shao-Lun; Zhang, Lin

2018-01-01

The miniaturization of spectrometer can broaden the application area of spectrometry, which has huge academic and industrial value. Among various miniaturization approaches, filter-based miniaturization is a promising implementation by utilizing broadband filters with distinct transmission functions. Mathematically, filter-based spectral reconstruction can be modeled as solving a system of linear equations. In this paper, we propose an algorithm of spectral reconstruction based on sparse optimization and dictionary learning. To verify the feasibility of the reconstruction algorithm, we design and implement a simple prototype of a filter-based miniature spectrometer. The experimental results demonstrate that sparse optimization is well applicable to spectral reconstruction whether the spectra are directly sparse or not. As for the non-directly sparse spectra, their sparsity can be enhanced by dictionary learning. In conclusion, the proposed approach has a bright application prospect in fabricating a practical miniature spectrometer. PMID:29470406

GABAergic system impairment in the hippocampus and superior temporal gyrus of patients with paranoid schizophrenia: A post-mortem study.

Science.gov (United States)

Steiner, Johann; Brisch, Ralf; Schiltz, Kolja; Dobrowolny, Henrik; Mawrin, Christian; Krzyżanowska, Marta; Bernstein, Hans-Gert; Jankowski, Zbigniew; Braun, Katharina; Schmitt, Andrea; Bogerts, Bernhard; Gos, Tomasz

2016-11-01

Glutamic acid decarboxylase (GAD) is a key enzyme in GABA synthesis and alterations in GABAergic neurotransmission related to glial abnormalities are thought to play a crucial role in the pathophysiology of schizophrenia. This study aimed to identify potential differences regarding the neuropil expression of GAD between paranoid and residual schizophrenia. GAD65/67 immunostained histological sections were evaluated by quantitative densitometric analysis of GAD-immunoreactive (ir) neuropil. Regions of interest were the hippocampal formation (CA1 field and dentate gyrus [DG]), superior temporal gyrus (STG), and laterodorsal thalamic nucleus (LD). Data from 16 post-mortem schizophrenia patient samples (10 paranoid and 6 residual schizophrenia cases) were compared with those from 16 matched controls. Overall, schizophrenia patients showed a lower GAD-ir neuropil density (P=0.014), particularly in the right CA1 (P=0.033). However, the diagnostic subgroups differed significantly (Pparanoid versus residual patients (P=0.036) and controls (Pparanoid versus residual schizophrenia cases (P=0.042). GAD-ir neuropil density correlated positively with antipsychotic dosage, particularly in CA1 (right: r=0.850, P=0.004; left: r=0.800, P=0.010). Our finding of decreased relative density of GAD-ir neuropil suggests hypofunction of the GABAergic system, particularly in hippocampal CA1 field and STG layer V of patients with paranoid schizophrenia. The finding that antipsychotic medication seems to counterbalance GABAergic hypofunction in schizophrenia patients suggests the possibility of exploring new treatment avenues which target this system. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhancement of a robust arcuate GABAergic input to gonadotropin-releasing hormone neurons in a model of polycystic ovarian syndrome.

Science.gov (United States)

Moore, Aleisha M; Prescott, Mel; Marshall, Christopher J; Yip, Siew Hoong; Campbell, Rebecca E

2015-01-13

Polycystic ovarian syndrome (PCOS), the leading cause of female infertility, is associated with an increase in luteinizing hormone (LH) pulse frequency, implicating abnormal steroid hormone feedback to gonadotropin-releasing hormone (GnRH) neurons. This study investigated whether modifications in the synaptically connected neuronal network of GnRH neurons could account for this pathology. The PCOS phenotype was induced in mice following prenatal androgen (PNA) exposure. Serial blood sampling confirmed that PNA elicits increased LH pulse frequency and impaired progesterone negative feedback in adult females, mimicking the neuroendocrine abnormalities of the clinical syndrome. Imaging of GnRH neurons revealed greater dendritic spine density that correlated with increased putative GABAergic but not glutamatergic inputs in PNA mice. Mapping of steroid hormone receptor expression revealed that PNA mice had 59% fewer progesterone receptor-expressing cells in the arcuate nucleus of the hypothalamus (ARN). To address whether increased GABA innervation to GnRH neurons originates in the ARN, a viral-mediated Cre-lox approach was taken to trace the projections of ARN GABA neurons in vivo. Remarkably, projections from ARN GABAergic neurons heavily contacted and even bundled with GnRH neuron dendrites, and the density of fibers apposing GnRH neurons was even greater in PNA mice (56%). Additionally, this ARN GABA population showed significantly less colocalization with progesterone receptor in PNA animals compared with controls. Together, these data describe a robust GABAergic circuit originating in the ARN that is enhanced in a model of PCOS and may underpin the neuroendocrine pathophysiology of the syndrome.

Learning-Dependent Plasticity of the Barrel Cortex Is Impaired by Restricting GABA-Ergic Transmission.

Science.gov (United States)

Posluszny, Anna; Liguz-Lecznar, Monika; Turzynska, Danuta; Zakrzewska, Renata; Bielecki, Maksymilian; Kossut, Malgorzata

2015-01-01

Experience-induced plastic changes in the cerebral cortex are accompanied by alterations in excitatory and inhibitory transmission. Increased excitatory drive, necessary for plasticity, precedes the occurrence of plastic change, while decreased inhibitory signaling often facilitates plasticity. However, an increase of inhibitory interactions was noted in some instances of experience-dependent changes. We previously reported an increase in the number of inhibitory markers in the barrel cortex of mice after fear conditioning engaging vibrissae, observed concurrently with enlargement of the cortical representational area of the row of vibrissae receiving conditioned stimulus (CS). We also observed that an increase of GABA level accompanied the conditioning. Here, to find whether unaltered GABAergic signaling is necessary for learning-dependent rewiring in the murine barrel cortex, we locally decreased GABA production in the barrel cortex or reduced transmission through GABAA receptors (GABAARs) at the time of the conditioning. Injections of 3-mercaptopropionic acid (3-MPA), an inhibitor of glutamic acid decarboxylase (GAD), into the barrel cortex prevented learning-induced enlargement of the conditioned vibrissae representation. A similar effect was observed after injection of gabazine, an antagonist of GABAARs. At the behavioral level, consistent conditioned response (cessation of head movements in response to CS) was impaired. These results show that appropriate functioning of the GABAergic system is required for both manifestation of functional cortical representation plasticity and for the development of a conditioned response.

Neuroimaging markers of glutamatergic and GABAergic systems in drug addiction: Relationships to resting-state functional connectivity.

Science.gov (United States)

Moeller, Scott J; London, Edythe D; Northoff, Georg

2016-02-01

Drug addiction is characterized by widespread abnormalities in brain function and neurochemistry, including drug-associated effects on concentrations of the excitatory and inhibitory neurotransmitters glutamate and gamma-aminobutyric acid (GABA), respectively. In healthy individuals, these neurotransmitters drive the resting state, a default condition of brain function also disrupted in addiction. Here, our primary goal was to review in vivo magnetic resonance spectroscopy and positron emission tomography studies that examined markers of glutamate and GABA abnormalities in human drug addiction. Addicted individuals tended to show decreases in these markers compared with healthy controls, but findings also varied by individual characteristics (e.g., abstinence length). Interestingly, select corticolimbic brain regions showing glutamatergic and/or GABAergic abnormalities have been similarly implicated in resting-state functional connectivity deficits in drug addiction. Thus, our secondary goals were to provide a brief review of this resting-state literature, and an initial rationale for the hypothesis that abnormalities in glutamatergic and/or GABAergic neurotransmission may underlie resting-state functional deficits in drug addiction. In doing so, we suggest future research directions and possible treatment implications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enhancement of GABAergic transmission by zolpidem, an imidazopyridine with preferential affinity for type I benzodiazepine receptors.

Science.gov (United States)

Biggio, G; Concas, A; Corda, M G; Serra, M

1989-02-28

The effect of zolpidem, an imidazopyridine derivative with high affinity at the type I benzodiazepine recognition site, on the function of the GABAA/ionophore receptor complex was studied in vitro. Zolpidem, mimicking the action of diazepam, increased [3H]GABA binding, enhanced muscimol-stimulated 36Cl- uptake and reduced [35S]TBPS binding in rat cortical membrane preparations. Zolpidem was less effective than diazepam on the above parameters. Zolpidem induced a lower increase of [3H]GABA binding (23 vs. 35%) and muscimol-stimulated 36Cl- uptake (22 vs. 40%) and a smaller decrease of [35S]TBPS binding (47 vs. 77%) than diazepam. The finding that zolpidem enhanced the function of GABAergic synapses with an efficacy qualitatively and quantitatively different from that of diazepam suggests that this compound is a partial agonist at the benzodiazepine recognition site. Thus, our results are consistent with the view that the biochemical and pharmacological profile of a benzodiazepine recognition site ligand reflects its efficacy to enhance GABAergic transmission. Whether the preferential affinity of zolpidem at the type I site is involved in its atypical biochemical and pharmacological profile remains to be clarified.

Plasma Structure and Behavior of Miniature Ring-Cusp Discharges

Science.gov (United States)

Mao, Hann-Shin

Miniature ring-cusp ion thrusters provide a unique blend of high efficiencies and millinewton level thrust for future spacecraft. These thrusters are attractive as a primary propulsion for small satellites that require a high delta V, and as a secondary propulsion for larger spacecraft that require precision formation flying, disturbance rejection, or attitude control. To ensure desirable performance throughout the life of such missions, an advancement in the understanding of the plasma structure and behavior of miniature ring-cusp discharges is required. A research model was fabricated to provide a simplified experimental test bed for the analysis of the plasma discharge chamber of a miniature ion thruster. The plasma source allowed for spatially resolved measurements with a Langmuir probe along a meridian plane. Probe measurements yielded plasma density, electron temperature, and plasma potential data. The magnetic field strength was varied along with the discharge current to determine the plasma behavior under various conditions. The structure of the plasma properties were found to be independent of the discharge power under the proper scaling. It was concluded that weaker magnetic fields can improve the overall performance for ion thruster operation. To further analyze the experimental measurements, a framework was developed based on the magnetic field. A flux aligned coordinate system was developed to decouple the perpendicular and parallel plasma motion with respect to the magnetic field. This was done using the stream function and magnetic scalar potential. Magnetic formulae provided intuition on the field profiles dependence on magnet dimensions. The flux aligned coordinate system showed that the plasma was isopycnic along constant stream function values. This was used to develop an empirical relation suitable for estimating the spatial behavior and to determine the plasma volume and loss areas. The plasma geometry estimates were applied to a control volume

A miniature X-ray tube based on carbon nanotube for an intraoral dental radiography

International Nuclear Information System (INIS)

Kim, Hyun Jin; Park, Han Beom; Lee, Ju Hyuk; Cho, Sung Oh

2016-01-01

The number of human teeth that can be radiographically taken is limited. Moreover, at least two X-ray shots are required to get images of teeth from both sides of the mouth. In order to overcome the disadvantages of conventional dental radiography, a dental radiograph has been proposed in which an X-ray tube is inserted into the mouth while an X-ray detector is placed outside the mouth. The miniature X-ray tube is required small size to insert into the mouth. Recently, we have fabricated a miniature x-ray tube with the diameter of 7 mm using a carbon nanotube (CNT) field. But, commercialized miniature X-ray tube were adopted a thermionic type using tungsten filament. The X-ray tubes adopted thermionic emission has a disadvantage of increasing temperature of x-ray tube. So it need to cooling system to cool x-ray tube. On the other hands, X-ray tubes adopted CNT field emitters don't need cooling systems because electrons are emitted from CNT by applying high voltage without heating. We have developed the miniature x-ray tube that produce x-ray with uniform spatial distribution based on carbon nanotube field emitters. The fabricated miniature x-ray tube can be stably and reliably operated at 50kV without any vacuum pump. The developed miniature X-ray tube was applied for intraoral dental radiography that employs an intra-oral CNT-based miniature X-ray tube and extra-oral X-ray detectors. An X-ray image of many teeth was successfully obtained by a single X-ray shot using the intra-oral miniature X-ray tube system. Furthermore, images of both molar teeth of pig were simultaneously obtained by a single X-ray shot. These results show that the intraoral dental radiography, which employs an intraoral miniature X-ray tube and an extraoral X-ray detector, performs better than conventional dental radiography

A miniature X-ray tube based on carbon nanotube for an intraoral dental radiography

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Jin; Park, Han Beom; Lee, Ju Hyuk; Cho, Sung Oh [KAIST, Daejeon (Korea, Republic of)

2016-05-15

The number of human teeth that can be radiographically taken is limited. Moreover, at least two X-ray shots are required to get images of teeth from both sides of the mouth. In order to overcome the disadvantages of conventional dental radiography, a dental radiograph has been proposed in which an X-ray tube is inserted into the mouth while an X-ray detector is placed outside the mouth. The miniature X-ray tube is required small size to insert into the mouth. Recently, we have fabricated a miniature x-ray tube with the diameter of 7 mm using a carbon nanotube (CNT) field. But, commercialized miniature X-ray tube were adopted a thermionic type using tungsten filament. The X-ray tubes adopted thermionic emission has a disadvantage of increasing temperature of x-ray tube. So it need to cooling system to cool x-ray tube. On the other hands, X-ray tubes adopted CNT field emitters don't need cooling systems because electrons are emitted from CNT by applying high voltage without heating. We have developed the miniature x-ray tube that produce x-ray with uniform spatial distribution based on carbon nanotube field emitters. The fabricated miniature x-ray tube can be stably and reliably operated at 50kV without any vacuum pump. The developed miniature X-ray tube was applied for intraoral dental radiography that employs an intra-oral CNT-based miniature X-ray tube and extra-oral X-ray detectors. An X-ray image of many teeth was successfully obtained by a single X-ray shot using the intra-oral miniature X-ray tube system. Furthermore, images of both molar teeth of pig were simultaneously obtained by a single X-ray shot. These results show that the intraoral dental radiography, which employs an intraoral miniature X-ray tube and an extraoral X-ray detector, performs better than conventional dental radiography.

Miniaturized Aptamer-Based Assays for Protein Detection

Directory of Open Access Journals (Sweden)

Alessandro Bosco

2016-09-01

Full Text Available The availability of devices for cancer biomarker detection at early stages of the disease is one of the most critical issues in biomedicine. Towards this goal, to increase the assay sensitivity, device miniaturization strategies empowered by the employment of high affinity protein binders constitute a valuable approach. In this work we propose two different surface-based miniaturized platforms for biomarker detection in body fluids: the first platform is an atomic force microscopy (AFM-based nanoarray, where AFM is used to generate functional nanoscale areas and to detect biorecognition through careful topographic measurements; the second platform consists of a miniaturized electrochemical cell to detect biomarkers through electrochemical impedance spectroscopy (EIS analysis. Both devices rely on robust and highly-specific protein binders as aptamers, and were tested for thrombin detection. An active layer of DNA-aptamer conjugates was immobilized via DNA directed immobilization on complementary single-stranded DNA self-assembled monolayers confined on a nano/micro area of a gold surface. Results obtained with these devices were compared with the output of surface plasmon resonance (SPR assays used as reference. We succeeded in capturing antigens in concentrations as low as a few nM. We put forward ideas to push the sensitivity further to the pM range, assuring low biosample volume (μL range assay conditions.

Does Spontaneous Favorability to Power (vs. Universalism) Values Predict Spontaneous Prejudice and Discrimination?

Science.gov (United States)

Souchon, Nicolas; Maio, Gregory R; Hanel, Paul H P; Bardin, Brigitte

2017-10-01

We conducted five studies testing whether an implicit measure of favorability toward power over universalism values predicts spontaneous prejudice and discrimination. Studies 1 (N = 192) and 2 (N = 86) examined correlations between spontaneous favorability toward power (vs. universalism) values, achievement (vs. benevolence) values, and a spontaneous measure of prejudice toward ethnic minorities. Study 3 (N = 159) tested whether conditioning participants to associate power values with positive adjectives and universalism values with negative adjectives (or inversely) affects spontaneous prejudice. Study 4 (N = 95) tested whether decision bias toward female handball players could be predicted by spontaneous attitude toward power (vs. universalism) values. Study 5 (N = 123) examined correlations between spontaneous attitude toward power (vs. universalism) values, spontaneous importance toward power (vs. universalism) values, and spontaneous prejudice toward Black African people. Spontaneous positivity toward power (vs. universalism) values was associated with spontaneous negativity toward minorities and predicted gender bias in a decision task, whereas the explicit measures did not. These results indicate that the implicit assessment of evaluative responses attached to human values helps to model value-attitude-behavior relations. © 2016 The Authors. Journal of Personality Published by Wiley Periodicals, Inc.

GDNF family ligands display distinct action profiles on cultured GABAergic and serotonergic neurons of rat ventral mesencephalon

DEFF Research Database (Denmark)

Ducray, Angélique; Krebs, Sandra H:; Schaller, Benoft

2006-01-01

Glial-cell-line-derived neurotrophic factor (GDNF), neurturin (NRTN), artemin (ARTN) and persephin (PSPN), known as the GDNF family ligands (GFLs), influence the development, survival and differentiation of cultured dopaminergic neurons from ventral mesencephalon (VM). Detailed knowledge about...... factors for VM GABAergic and serotonergic neurons, demonstrating characteristic individual action profiles emphasizing their important and distinct roles during brain development....

Microsupercapacitors as miniaturized energy-storage components for on-chip electronics

Science.gov (United States)

Kyeremateng, Nana Amponsah; Brousse, Thierry; Pech, David

2017-01-01

The push towards miniaturized electronics calls for the development of miniaturized energy-storage components that can enable sustained, autonomous operation of electronic devices for applications such as wearable gadgets and wireless sensor networks. Microsupercapacitors have been targeted as a viable route for this purpose, because, though storing less energy than microbatteries, they can be charged and discharged much more rapidly and have an almost unlimited lifetime. In this Review, we discuss the progress and the prospects of integrated miniaturized supercapacitors. In particular, we discuss their power performances and emphasize the need of a three-dimensional design to boost their energy-storage capacity. This is obtainable, for example, through self-supported nanostructured electrodes. We also critically evaluate the performance metrics currently used in the literature to characterize microsupercapacitors and offer general guidelines to benchmark performances towards prospective applications.

Miniature Active Space Radiation Dosimeter, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Space Micro will extend our Phase I R&D to develop a family of miniature, active space radiation dosimeters/particle counters, with a focus on biological/manned...

Miniaturized radiation chirper

International Nuclear Information System (INIS)

Umbarger, C.J.; Wolf, M.A.

1980-01-01

A miniaturized radiation chirper for use with a small battery supplying on the order of 5 volts is described. A poor quality CdTe crystal which is not necessarily suitable for high resolution gamma ray spectroscopy is incorporated with appropriate electronics so that the chirper emits an audible noise at a rate that is proportional to radiation exposure level. The chirper is intended to serve as a personnel radiation warning device that utilizes new and novel electronics with a novel detector, a CdTe crystal. The resultant device is much smaller and has much longer battery life than existing chirpers

Midbrain and forebrain patterning delivers immunocytochemically and functionally similar populations of neuropeptide Y containing GABAergic neurons.

Science.gov (United States)

Khaira, S K; Nefzger, C M; Beh, S J; Pouton, C W; Haynes, J M

2011-09-01

Neurons differentiated in vitro from embryonic stem cells (ESCs) have the potential to serve both as models of disease states and in drug discovery programs. In this study, we use sonic hedgehog (SHH) and fibroblast growth factor 8 (FGF-8) to enrich for forebrain and midbrain phenotypes from mouse ESCs. We then investigate, using Ca(2+) imaging and [(3)H]-GABA release studies, whether the GABAergic neurons produced exhibit distinct functional phenotypes. At day 24 of differentiation, reverse transcriptase-PCR showed the presence of both forebrain (Bf-1, Hesx1, Pgc-1α, Six3) and midbrain (GATA2, GATA3) selective mRNA markers in developing forebrain-enriched cultures. All markers were present in midbrain cultures except for Bf-1 and Pgc-1α. Irrespective of culture conditions all GABA immunoreactive neurons were also immunoreactive to neuropeptide Y (NPY) antibodies. Forebrain and midbrain GABAergic neurons responded to ATP (1 mM), L-glutamate (30 μM), noradrenaline (30 μM), acetylcholine (30 μM) and dopamine (30 μM), with similar elevations of intracellular Ca(2+)([Ca(2+)](i)). The presence of GABA(A) and GABA(B) antagonists, bicuculline (30 μM) and CGP55845 (1 μM), increased the elevation of [Ca(2+)](i) in response to dopamine (30 μM) in midbrain, but not forebrain GABAergic neurons. All agonists, except dopamine, elicited similar [(3)H]-GABA release from forebrain and midbrain cultures. Dopamine (30 μM) did not stimulate significant [(3)H]-GABA release in midbrain cultures, although it was effective in forebrain cultures. This study shows that differentiating neurons toward a midbrain fate restricts the expression of forebrain markers. Forebrain differentiation results in the expression of forebrain and midbrain markers. All GABA(+) neurons contain NPY, and show similar agonist-induced elevations of [Ca(2+)](i) and [(3)H]-GABA release. This study indicates that the pharmacological phenotype of these particular neurons may be independent of the addition of

Miniaturized integration of a fluorescence microscope

Science.gov (United States)

Ghosh, Kunal K.; Burns, Laurie D.; Cocker, Eric D.; Nimmerjahn, Axel; Ziv, Yaniv; Gamal, Abbas El; Schnitzer, Mark J.

2013-01-01

The light microscope is traditionally an instrument of substantial size and expense. Its miniaturized integration would enable many new applications based on mass-producible, tiny microscopes. Key prospective usages include brain imaging in behaving animals towards relating cellular dynamics to animal behavior. Here we introduce a miniature (1.9 g) integrated fluorescence microscope made from mass-producible parts, including semiconductor light source and sensor. This device enables high-speed cellular-level imaging across ∼0.5 mm2 areas in active mice. This capability allowed concurrent tracking of Ca2+ spiking in >200 Purkinje neurons across nine cerebellar microzones. During mouse locomotion, individual microzones exhibited large-scale, synchronized Ca2+ spiking. This is a mesoscopic neural dynamic missed by prior techniques for studying the brain at other length scales. Overall, the integrated microscope is a potentially transformative technology that permits distribution to many animals and enables diverse usages, such as portable diagnostics or microscope arrays for large-scale screens. PMID:21909102

Glutamatergic and GABAergic gene sets in attention-deficit/hyperactivity disorder

DEFF Research Database (Denmark)

Naaijen, Jill; Bralten, Janita; Poelmans, Geert

2017-01-01

Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorders (ASD) often co-occur. Both are highly heritable; however, it has been difficult to discover genetic risk variants. Glutamate and GABA are main excitatory and inhibitory neurotransmitters in the brain; their balance...... within glutamatergic and GABAergic genes were investigated using the MAGMA software in an ADHD case-only sample (n=931), in which we assessed ASD symptoms and response inhibition on a Stop task. Gene set analysis for ADHD symptom severity, divided into inattention and hyperactivity/impulsivity symptoms...... is essential for proper brain development and functioning. In this study we investigated the role of glutamate and GABA genetics in ADHD severity, autism symptom severity and inhibitory performance, based on gene set analysis, an approach to investigate multiple genetic variants simultaneously. Common variants...

Miniature magnetic fluid seal working in liquid environments

Energy Technology Data Exchange (ETDEWEB)

Mitamura, Yoshinori, E-mail: ymitamura@par.odn.ne.jp [Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814 (Japan); Durst, Christopher A., E-mail: chris@procyrion.com [Procyrion, Inc., Houston, TX 77027 (United States)

2017-06-01

This study was carried out to develop a miniature magnetic fluid (MF) seal working in a liquid environment. The miniature MF seal is intended for use in a catheter blood pump. The requirements for the MF seal included a size of less than Ø4×4.5 mm, shaft diameter of 1 mm, sealing pressure of 200 mmHg, shaft speed of up to 40000 rpm, and life of one month. The miniature MF seal was composed of an NdFeB magnet (Ø4×Ø2×1) sandwiched between two pole pieces (Ø4×Ø1.1×0.5). A shield (Ø4×Ø1.2×1.5) was placed on the pole piece facing the liquid to minimize the influence of pump flow on the MF. The seal was installed on a Ø1 shaft. A seal was formed by injecting MF (Ms: 47.8 kA/m and η: 0.5 Pa·sec) into the gap between the pole pieces and the shaft. Total volume of the MF seal was 44 μL. A sealing pressure of 370 mmHg was obtained at motor speeds of 0-40,000 rpm. The seal remained perfect for 10 days in saline under the condition of a pump flow of 1.5 L/min (The test was terminated in accordance with plans). The seal remained intact after ethylene oxide sterilization during which the seal was exposed to high pressures. In conclusion, the newly developed MF seal will be useful for a catheter pump. - Highlights: • A miniature magnetic fluid seal working in a liquid environment was developed. • The seal can be installed on Ø1 mm shaft and can seal against 370 mmHg at 40000 rpm. • The magnetic fluid seal will be useful for a catheter blood pump.

Evolution in miniaturized column liquid chromatography instrumentation and applications: An overview.

Science.gov (United States)

Nazario, Carlos E D; Silva, Meire R; Franco, Maraíssa S; Lanças, Fernando M

2015-11-20

The purpose of this article is to underline the miniaturized LC instrumental system and describe the evolution of commercially available systems by discussing their advantages and drawbacks. Nowadays, there are already many miniaturized LC systems available with a great variety of pump design, interface and detectors as well as efficient columns technologies and reduced connections devices. The solvent delivery systems are able to drive the mobile phase without flow splitters and promote gradient elution using either dual piston reciprocating or syringe-type pumps. The mass spectrometry as detection system is the most widely used detection system; among many alternative ionization sources direct-EI LC-MS is a promising alternative to APCI. In addition, capillary columns are now available showing many possibilities of stationary phases, inner diameters and hardware materials. This review provides a discussion about miniaturized LC demonstrating fundamentals and instrumentals' aspects of the commercially available miniaturized LC instrumental system mainly nano and micro LC formats. This review also covers the recent developments and trends in instrumentation, capillary and nano columns, and several applications of this very important and promising field. Copyright © 2015 Elsevier B.V. All rights reserved.

An Intraoral Miniature X-ray Tube Based on Carbon Nanotubes for Dental Radiography

OpenAIRE

Hyun Jin Kim; Hyun Nam Kim; Hamid Saeed Raza; Han Beom Park; Sung Oh Cho

2016-01-01

A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be ...

Miniature fiber Bragg grating sensor interrogator (FBG-Transceiver) system

Science.gov (United States)

Mendoza, Edgar A.; Kempen, Cornelia; Lopatin, Craig

2007-04-01

This paper describes recent progress conducted towards the development of a miniature fiber Bragg grating sensor interrogator (FBG-Transceiver TM) system based on multi-channel integrated optic sensor (InOSense TM) microchip technology. The hybrid InOSense TM microchip technology enables the integration of all of the functionalities, both passive and active, of conventional bench top FBG sensor interrogator systems, packaged in a miniaturized, low power operation, 2-cm x 5-cm package suitable for the long-term structural health monitoring in applications where size, weight, and power are critical for operation. The FBG-Transceiver system uses active optoelectronic components monolithically integrated to the InOSense TM microchip, a microprocessor controlled signal processing electronics board capable of processing the FBG sensors signals related to stress-strain and temperature as well as vibration and acoustics. The FBG-Transceiver TM system represents a new, reliable, highly robust technology that can be used to accurately monitor the status of an array of distributed fiber optic Bragg grating sensors installed in critical infrastructures. Its miniature package, low power operation, and state-of-the-art data communications architecture, all at a very affordable price makes it a very attractive solution for a large number of SHM/NDI applications in aerospace, naval and maritime industry, civil structures like bridges, buildings and dams, the oil and chemical industry, and for homeland security applications. The miniature, cost-efficient FBG-Transceiver TM system is poised to revolutionize the field of structural health monitoring and nondestructive inspection market. The sponsor of this program is NAVAIR under a DOD SBIR contract.

MIT miniaturized disk bend test

International Nuclear Information System (INIS)

Harling, O.K.; Lee, M.; Sohn, D.S.; Kohse, G.; Lau, C.W.

1983-01-01

A miniaturized disk bend test (MDBT) using transmission electron microscopy specimens for the determination of various mechanical properties is being developed at MIT. Recent progress in obtaining strengths and ductilities of highly irradiated metal alloys is reviewed. Other mechanical properties can also be obtained using the MDBT approach. Progress in fatigue testing and in determination of the ductile-to-brittle transition temperature is reviewed briefly. 11 figures

High prevalence of the c.74A>C SPINK1 variant in miniature and standard Schnauzers.

Science.gov (United States)

Furrow, E; Armstrong, P J; Patterson, E E

2012-01-01

Variants in the serine protease inhibitor Kazal type 1 (SPINK1) gene have been associated with pancreatitis in Miniature Schnauzers. Replication of the association in an independent population is necessary to determine if genetic screening for SPINK1 variants should be considered in clinical practice. An association between the SPINK1 exonic variant c.74A > C and pancreatitis exists in Miniature Schnauzers. In addition, the variant is absent or rare in Standard Schnauzers, a related breed that is not reported to have an increased risk for pancreatitis. Case-control study. Seventeen Miniature Schnauzers with pancreatitis (cases), 60 mature Miniature Schnauzers with no substantial history of gastrointestinal signs in their lifetime (controls), and 31 Standard Schnauzers of unknown pancreatitis status. A PCR-RFLP assay was used to genotype dogs for the c.74A > C SPINK1 variant. Allele and genotype frequencies were reported for Schnauzers and compared between case and control Miniature Schnauzers. The c.74A > C variant was the major allele in both Schnauzer breeds with a frequency of 0.77 in Miniatures and 0.55 in Standards. The allele and genotype frequencies were similar between Miniature Schnauzers with and without a history of pancreatitis and did not impart an increased risk for pancreatitis. Genotyping a larger population of the Miniature Schnauzer breed than a previous study, along with a Standard Schnauzer cohort, demonstrated that the SPINK1 c.74A > C variant is a common polymorphism in the Schnauzer lineage. Furthermore, we were unable to confirm a relationship between the variant and clinically detectable pancreatitis in Miniature Schnauzers. Copyright © 2012 by the American College of Veterinary Internal Medicine.

Miniature piezo electric vacuum inlet valve

Science.gov (United States)

Keville, Robert F.; Dietrich, Daniel D.

1998-03-24

A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability. The low power (piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three.

[Effect of activation and blockade of the GABA-ergic system of the substantia nigra in the midbrain on the realization of conditioned food reflexes in dogs].

Science.gov (United States)

Iakimovskiĭ, A F

1988-01-01

Bilateral injection of 45 mcg of GABA into substantia nigra pars compacta produced in dogs a manifested improvement of parameters of the conditioned differentiation inhibition but failed to influence the positive Pavlovian alimentary conditioned reflex. Injection of GABA synaptic antagonist--picrotoxin impaired conditioned alimentary behaviour. Numerous injections of the GABAergic pharmacological agents resulted in motor disturbance--rotatory movements--and skin trophic deviations. The data obtained and literature references give ground for discussion of the role of striato-nigral and internal GABAergic substantia nigra systems in the positive modulation of adaptive alimentary behaviour and conditioned stimuli differentiation.

Miniature fiber-optic multiphoton microscopy system using frequency-doubled femtosecond Er-doped fiber laser.

Science.gov (United States)

Huang, Lin; Mills, Arthur K; Zhao, Yuan; Jones, David J; Tang, Shuo

2016-05-01

We report on a miniature fiber-optic multiphoton microscopy (MPM) system based on a frequency-doubled femtosecond Er-doped fiber laser. The femtosecond pulses from the laser source are delivered to the miniature fiber-optic probe at 1.58 µm wavelength, where a standard single mode fiber is used for delivery without the need of free-space dispersion compensation components. The beam is frequency-doubled inside the probe by a periodically poled MgO:LiNbO3 crystal. Frequency-doubled pulses at 786 nm with a maximum power of 80 mW and a pulsewidth of 150 fs are obtained and applied to excite intrinsic signals from tissues. A MEMS scanner, a miniature objective, and a multimode collection fiber are further used to make the probe compact. The miniature fiber-optic MPM system is highly portable and robust. Ex vivo multiphoton imaging of mammalian skins demonstrates the capability of the system in imaging biological tissues. The results show that the miniature fiber-optic MPM system using frequency-doubled femtosecond fiber laser can potentially bring the MPM imaging for clinical applications.

Nucleus accumbens opioid, GABaergic, and dopaminergic modulation of palatable food motivation: contrasting effects revealed by a progressive ratio study in the rat.

Science.gov (United States)

Zhang, Min; Balmadrid, Christian; Kelley, Ann E

2003-04-01

The current studies were designed to evaluate whether incentive motivation for palatable food is altered after manipulations of opioid, GABAergic, and dopaminergic transmission within the nucleus accumbens. A progressive ratio schedule was used to measure lever-pressing for sugar pellets after microinfusion of drugs into the nucleus accumbens in non-food-deprived rats. The mu opioid agonist D-Ala2, NMe-Phe4, Glyo15-enkephalin and the indirect dopamine agonist amphetamine induced a marked increase in break point and correct lever-presses; the GABA(A) agonist muscimol did not affect breakpoint or lever-presses. The data suggest that opioid, dopaminergic, and GABAergic systems within the accumbens differentially modulate food-seeking behavior through mechanisms related to hedonic evaluation of food, incentive salience, and control of motor feeding circuits, respectively.

Miniaturized star tracker for micro spacecraft with high angular rate

Science.gov (United States)

Li, Jianhua; Li, Zhifeng; Niu, Zhenhong; Liu, Jiaqi

2017-10-01

There is a clear need for miniaturized, lightweight, accurate and inexpensive star tracker for spacecraft with large anglar rate. To face these new constraints, the Beijing Institute of Space Long March Vehicle has designed, built and flown a low cost miniaturized star tracker that provides autonomous ("Lost in Space") inertial attitude determination, 2 Hz 3-axis star tracking, and digital imaging with embedded compression. Detector with high sensitivity is adopted to meet the dynamic and miniature requirement. A Sun and Moon avoiding method based on the calculation of Sun and Moon's vector by astronomical theory is proposed. The produced prototype weight 0.84kg, and can be used for a spacecraft with 6°/s anglar rate. The average angle measure error is less than 43 arc second. The ground verification and application of the star tracker during the pick-up flight test showed that the capability of the product meet the requirement.

Hippocampal dendritic spines remodeling and fear memory are modulated by GABAergic signaling within the basolateral amygdala complex.

Science.gov (United States)

Giachero, Marcelo; Calfa, Gaston D; Molina, Victor A

2015-05-01

GABAergic signaling in the basolateral amygdala complex (BLA) plays a crucial role on the modulation of the stress influence on fear memory. Moreover, accumulating evidence suggests that the dorsal hippocampus (DH) is a downstream target of BLA neurons in contextual fear. Given that hippocampal structural plasticity is proposed to provide a substrate for the storage of long-term memories, the main aim of this study is to evaluate the modulation of GABA neurotransmission in the BLA on spine density in the DH following stress on contextual fear learning. The present findings show that prior stressful experience promoted contextual fear memory and enhanced spine density in the DH. Intra-BLA infusion of midazolam, a positive modulator of GABAa sites, prevented the facilitating influence of stress on both fear retention and hippocampal dendritic spine remodeling. Similarly to the stress-induced effects, the blockade of GABAa sites within the BLA ameliorated fear memory emergence and induced structural remodeling in the DH. These findings suggest that GABAergic transmission in BLA modulates the structural changes in DH associated to the influence of stress on fear memory. © 2015 Wiley Periodicals, Inc.

Plans for miniature machining at LASL

International Nuclear Information System (INIS)

Rhorer, R.L.

1979-01-01

A special shop for making miniature or very small parts is being established within the LASL Shop Department, and one of the machine tools for this shop is a high precision lathe. The report describes a method based on scale modeling analysis which was used to define the specific requirements for this lathe

Fabrication of a Miniaturized ZnO Nanowire Accelerometer and Its Performance Tests

Directory of Open Access Journals (Sweden)

Hyun Chan Kim

2016-09-01

Full Text Available This paper reports a miniaturized piezoelectric accelerometer suitable for a small haptic actuator array. The accelerometer is made with zinc oxide (ZnO nanowire (NW grown on a copper wafer by a hydrothermal process. The size of the accelerometer is 1.5 × 1.5 mm2, thus fitting the 1.8 × 1.8 mm2 haptic actuator array cell. The detailed fabrication process of the miniaturized accelerometer is illustrated. Performance evaluation of the fabricated accelerometer is conducted by comparing it with a commercial piezoelectric accelerometer. The output current of the fabricated accelerometer increases linearly with the acceleration. The miniaturized ZnO NW accelerometer is feasible for acceleration measurement of small and lightweight devices.

Miniaturized Airborne Imaging Central Server System, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The innovation is a miniaturized airborne imaging central server system (MAICSS). MAICSS is designed as a high-performance-computer-based electronic backend that...

Miniaturized Airborne Imaging Central Server System, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The innovation is a miniaturized airborne imaging central server system (MAICSS). MAICSS is designed as a high-performance computer-based electronic backend that...

Miniaturized optical sensors based on lens arrays

DEFF Research Database (Denmark)

Hanson, Steen Grüner; Jakobsen, M.L.; Larsen, H.E.

2005-01-01

A suite of optical sensors based on the use of lenticular arrays for probing mechanical deflections will be displayed. The optical systems are well suited for miniaturization, and utilize speckles as the information-carriers. This implementation allows for acquiring directional information...

c-Fos expression is elevated in GABAergic interneurons of the gustatory cortex following novel taste learning.

Science.gov (United States)

Doron, Guy; Rosenblum, Kobi

2010-07-01

Long-term sensory memories are considered to be stored in the relevant cortical region subserving the given modality. We and others have recently identified a series of molecular alterations in the gustatory cortex (GC) of the rat at different time intervals following novel taste learning. Some of these correlative modifications were also necessary for taste memory acquisition and/or consolidation. However, very little is known about the localization of these molecular modifications within the GC or about the functional activation of the GC hours after novel taste learning. Here, we hypothesize that inhibitory interneurons are activated in the GC on a scale of hours following learning and used c-Fos expression and confocal microscopy with different markers to test this hypothesis. We found that GABAergic interneurons are activated in the GC in correlation with novel taste learning. The activation was evident in the deep but not superficial layers of the dysgranular insular cortex. These results suggest that the GABAergic machinery in the deep layers of the GC participates in the processing of taste information hours after learning, and provide evidence for the involvement of a local cortical circuit not only during acquisition of new information but also during off-line processing and consolidation of taste information.

Miniature Inertial and Augmentation Sensors for Integrated Inertial/GPS Based Navigation Applications

Science.gov (United States)

2010-03-01

Magnetometer (Ref [23]) Until miniature atomic magnetometers transition from laboratory demonstration units to a mass produced product, fluxgate ...and/or magnetoresistive designs are a better suited magnetometer technology for a miniature navigation system. Figure 8 below shows the basic fluxgate ...is required to resolve magnetic field orientation. Fig 8. Fluxgate Magnetometer Schematic The PNI Sensor Corporation (Santa Rosa, CA

Novel Miniature Spectrometer For Remote Chemical Detection

International Nuclear Information System (INIS)

Pipino, Andrew C.R.

2000-01-01

New chemical sensing technologies are critically important for addressing many of EM's priority needs as discussed in detail at http://emsp.em.doe.gov/needs. Many technology needs were addressed by this research. For example, improved detection strategies are needed for non-aqueous phase liquids (NAPL's), such as PCE (Cl2C=CCl2) and TCE (HClC=CCl2), which persist in the environment due their highly stable structures. By developing a miniature, ultra-sensitive, selective, and field-deployable detector for NAPL's, the approximate source location could be determined with minimal investigative expense. Contaminant plumes could also be characterized in detail. The miniature spectrometer developed under Project No.60231 could also permit accurate rate measurements in less time, either in the field or the laboratory, which are critically important in the development, testing, and ultimate utilization of models for describing contaminant transport. The technology could also be used for long-term groundwater monitoring or long-term stewardship in general. Many science needs are also addressed by the Project 60231, since the effort significantly advances the measurement science of chemical detection. Developed under Project No.60231, evanescent wave cavity ring-down spectroscopy (EW-CRDS) is a novel form of CRDS, which is an the emerging optical absorption technique. Several review articles on CRDS, which has been generally applied only to gas-phase diagnostics, have been published1-3. EW-CRDS4-10 forms the basis for a new class of chemical sensors that extends CRDS to other states of matter and leads to a miniaturized version of the concept. EW-CRDS uses miniature solid-state optical resonators that incorporate one or more total internal reflection (TIR) surfaces, which create evanescent waves. The evanescent waves emanate from the TIR surfaces, sampling the surrounding medium. The utility of evanescent waves in chemical analysis forms the basis for the field of attenuated

Inherited retinal dysplasia and persistent hyperplastic primary vitreous in Miniature Schnauzer dogs.

Science.gov (United States)

Grahn, Bruce H; Storey, Eric S; McMillan, Catherine

2004-01-01

The objectives of this study were to define the clinical syndrome of retinal dysplasia and persistent primary vitreous in Miniature Schnauzer dogs and determine the etiology. We examined 106 Miniature Schnauzers using a biomicroscope and indirect ophthalmoscope. The anterior and posterior segments of affected dogs were photographed. Four enucleated eyes were examined using routine light microscopy and scanning electron microscopy. A pedigree was constructed and related dogs were test-bred to define the mode of inheritance of this syndrome. Congenital retinal dysplasia was confirmed in 24 of 106 related Miniature Schnauzer dogs. Physical and postmortem examinations revealed that congenital abnormalities were limited to the eyes. Biomicroscopic, indirect ophthalmoscopic, and neuro-ophthalmic examinations confirmed that some of these dogs were blind secondary to bilateral retinal dysplasia and detachment (nonattachment) (n = 13), and the remainder had generalized retinal dysplasia (n = 11). Fifteen of these dogs were also diagnosed with unilateral (n = 9) or bilateral (n = 6) persistent hyperplastic primary vitreous. Nutritional, infectious, or toxic etiologies were not evident on physical, postmortem, light microscopic, or transmitting and scanning electron microscopic examination of four affected Miniature Schnauzers. We examined the pedigree and determined that an autosomal recessive mode of inheritance was most likely. Three test-bred litters including those from affected parents, carrier and affected parents, and carrier parents confirmed this mode of inheritance. This study confirms that retinal dysplasia and persistent hyperplastic primary vitreous is a congenital abnormality that is inherited as an autosomal recessive condition in Miniature Schnauzers.

An Intraoral Miniature X-ray Tube Based on Carbon Nanotubes for Dental Radiography

Directory of Open Access Journals (Sweden)

Hyun Jin Kim

2016-06-01

Full Text Available A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube.

An intraoral miniature x-ray tube based on carbon nanotubes for dental radiography

International Nuclear Information System (INIS)

Kim, Hyun Jin; Kim, Hyun Nam; Raza, Hamid Saeed; Park, Han Beom; Cho, Sung Oh

2016-01-01

A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube

An intraoral miniature x-ray tube based on carbon nanotubes for dental radiography

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Jin; Kim, Hyun Nam; Raza, Hamid Saeed; Park, Han Beom; Cho, Sung Oh [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2016-06-15

A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube.

Near-net shape manufacturing of miniature spur gears by wire spark erosion machining

CERN Document Server

Gupta, Kapil

2016-01-01

This work describes an experimental investigation with the aim to evaluate and establish wire spark erosion machining (WSEM) as a viable alternative for high quality miniature gear manufacturing. External spur type miniature brass (ASTM 858) gears with 12 teeth, 9.8 mm outside diameter and 5 mm face width were manufactured by WSEM. The research work was accomplished in four distinct experimental stages viz., preliminary, pilot, main and confirmation. The aim, scope and findings of each stage are progressively presented and discussed. In essence, the investigation found that it was possible to manufacture miniature gears to high quality by using WSEM. Gears up to DIN 5 quality with a good surface finish (1.2 µm average roughness) and satisfactory surface integrity were achieved. The results suggest that WSEM should be considered a viable alternative to conventional miniature gear manufacturing techniques and that in some instances it may even be superior. This work will prove useful to researchers and profess...

Technologies for highly miniaturized autonomous sensor networks

NARCIS (Netherlands)

Baert, K.; Gyselinckx, B.; Torfs, T.; Leonov, V.; Yazicioglu, F.; Brebels, S.; Donnay, S.; Vanfleteren, J.; Beyne, E.; Hoof, C. van

2006-01-01

Recent results of the autonomous sensor research program HUMAN++ will be summarized in this paper. The research program aims to achieve highly miniaturized and (nearly) autonomous sensor systems that assist our health and comfort. Although the application examples are dedicated to human

Miniaturized measurement system for ammonia in air

NARCIS (Netherlands)

Timmer, B.H.; van Delft, K.M.; Otjes, R.P.; Olthuis, Wouter; van den Berg, Albert

2004-01-01

The development of a miniaturized ammonia sensor made using microsystem technology is described. Gas is sampled in a sampler comprising two opposite channels separated by a gas permeable, water repellent polypropylene membrane. Subsequently, the acid sample solution is pumped into a selector where

Design and analysis of miniature tri-axial fluxgate magnetometer

Science.gov (United States)

Zhi, Menghui; Tang, Liang; Qiao, Donghai

2017-02-01

The detection technology of weak magnetic field is widely used in Earth resource survey and geomagnetic navigation. Useful magnetic field information can be obtained by processing and analyzing the measurement data from magnetic sensors. A miniature tri-axial fluxgate magnetometer is proposed in this paper. This miniature tri-axial fluxgate magnetometer with ring-core structure has a dynamic range of the Earth’s field ±65,000 nT, resolution of several nT. It has three independent parts placed in three perpendicular planes for measuring three orthogonal magnetic field components, respectively. A field-programmable gate array (FPGA) is used to generate stimulation signal, analog-to-digital (A/D) convertor control signal, and feedback digital-to-analog (D/A) control signal. Design and analysis details are given to improve the dynamic range, sensitivity, resolution, and linearity. Our prototype was measured and compared with a commercial standard Magson fluxgate magnetometer as a reference. The results show that our miniature fluxgate magnetometer can follow the Magson’s change trend well. When used as a magnetic compass, our prototype only has ± 0.3∘ deviation compared with standard magnetic compass.

Miniaturized Charpy test for reactor pressure vessel embrittlement characterization

Energy Technology Data Exchange (ETDEWEB)

Manahan, M.P. Sr. [MPM Research and Consulting, Lemont, PA (United States)

1999-10-01

Modifications were made to a conventional Charpy machine to accommodate the miniaturized Charpy V-Notch (MCVN) specimens which were fabricated from an archived reactor pressure vessel (RPV) steel. Over 100 dynamic MCVN tests were performed and compared to the results from conventional Charpy V-Notch (CVN) tests to demonstrate the efficacy of the miniature specimen test. The optimized sidegrooved MCVN specimens exhibit transitional fracture behavior over essentially the same temperature range as the CVN specimens which indicates that the stress fields in the MCVN specimens reasonably simulate those of the CVN specimens and this fact has been observed in finite element calculations. This result demonstrates a significant breakthrough since it is now possible to measure the ductile-brittle transition temperature (DBTT) using miniature specimens with only small correction factors, and for some materials as in the present study, without the need for any correction factor at all. This development simplifies data interpretation and will facilitate future regulatory acceptance. The non-sidegrooved specimens yield energy-temperature data which is significantly shifted downward in temperature (non-conservative) as a result of the loss of constraint which accompanies size reduction.

SMARBot: a modular miniature mobile robot platform

Science.gov (United States)

Meng, Yan; Johnson, Kerry; Simms, Brian; Conforth, Matthew

2008-04-01

Miniature robots have many advantages over their larger counterparts, such as low cost, low power, and easy to build a large scale team for complex tasks. Heterogeneous multi miniature robots could provide powerful situation awareness capability due to different locomotion capabilities and sensor information. However, it would be expensive and time consuming to develop specific embedded system for different type of robots. In this paper, we propose a generic modular embedded system architecture called SMARbot (Stevens Modular Autonomous Robot), which consists of a set of hardware and software modules that can be configured to construct various types of robot systems. These modules include a high performance microprocessor, a reconfigurable hardware component, wireless communication, and diverse sensor and actuator interfaces. The design of all the modules in electrical subsystem, the selection criteria for module components, and the real-time operating system are described. Some proofs of concept experimental results are also presented.

A miniature spark counter for public communication and education

International Nuclear Information System (INIS)

Mao, C.H.; Weng, P.S.

1987-01-01

The fabrication of a miniature spark counter for public communication and education using naturally occurring radon as a radioactive source without involving any man-made radioactivity is described. The battery-powered miniature spark counter weighs 2.07 kg with a volume of 4.844 x 10/sup -4/ m/sup 3/. The circuitry consists of seven major components: timer, high-voltage power supply, attenuator, noninverting amplifier, low-pass filter, one-shot generator, and counter. Cellulose nitrate films irradiated with alpha particles from radon emanating from soil were etched and counted. The visible sparks during counting are rather heuristic, which can be used to demonstrate naturally occurring radioactivity in classrooms or showplaces

Lobar holoprosencephaly in a Miniature Schnauzer with hypodipsic hypernatremia.

Science.gov (United States)

Sullivan, Stacey A; Harmon, Barry G; Purinton, P Thomas; Greene, Craig E; Glerum, Leigh E

2003-12-15

A 9-month-old male Miniature Schnauzer was examined because of a lifelong history of behavioral abnormalities, including hypodipsia. Diagnostic evaluation revealed marked hypernatremia and a single forebrain ventricle. The behavioral abnormalities did not resolve with correction of the hypernatremia, and the dog was euthanatized. At necropsy, midline forebrain structures were absent or reduced in size, and normally paired forebrain structures were incompletely separated. Findings were diagnostic for holoprosencephaly, a potentially genetic disorder and the likely cause of the hypodipsia. Similar evaluation of affected Miniature Schnauzer dogs may reveal whether holoprosencephaly routinely underlies the thirst deficiency that may be seen in dogs of this breed.

Miniature Sensor for Aerosol Mass Measurements, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR project seeks to develop a miniature sensor for mass measurement of size-classified aerosols. A cascade impactor will be used to classify aerosol sample...

Miniaturized radiation detector with custom synthesized diamond crystal as sensor

International Nuclear Information System (INIS)

Grobbelaar, J.H.; Burns, R.C.; Nam, T.L.; Keddy, R.J.

1991-01-01

A miniaturized detector consisting of three custom built hybrid circuits, a counter and a miniature high voltage power supply was designed to operate with custom synthesized Type Ib diamond crystals as sensors. Thick-film technology was incorporated in the circuit design. With a crystal having a volume of approximately 10 mm 3 and containing approximately 60 ppm paramagnetic nitrogen, the detector was capable of measuring γ-ray dose-rates as low as 7.5 μ Gy h -1 . The response characteristic was linear up to 1 cGy h -1 . (orig.)

Fabrication of miniaturized electrostatic deflectors using LIGA

International Nuclear Information System (INIS)

Jackson, K.H.; Khan-Malek, C.; Muray, L.P.

1997-01-01

Miniaturized electron beam columns (open-quotes microcolumnsclose quotes) have been demonstrated to be suitable candidates for scanning electron microscopy (SEM), e-beam lithography and other high resolution, low voltage applications. In the present technology, microcolumns consist of open-quotes selectively scaledclose quotes micro-sized lenses and apertures, fabricated from silicon membranes with e-beam lithography, reactive ion beam etching and other semiconductor thin-film techniques. These miniaturized electron-optical elements provide significant advantages over conventional optics in performance and ease of fabrication. Since lens aberrations scale roughly with size, it is possible to fabricate simple microcolumns with extremely high brightness sources and electrostatic objective lenses, with resolution and beam current comparable to conventional e-beam columns. Moreover since microcolumns typically operate at low voltages (1 KeV), the proximity effects encountered in e-beam lithography become negligible. For high throughput applications, batch fabrication methods may be used to build large parallel arrays of microcolumns. To date, the best reported performance with a 1 keV cold field emission cathode, is 30 nm resolution at a working distance of 2mm in a 3.5mm column. Fabrication of the microcolumn deflector and stigmator, however, have remained beyond the capabilities of conventional machining operations and semiconductor processing technology. This work examines the LIGA process as a superior alternative to fabrication of the deflectors, especially in terms of degree of miniaturization, dimensional control, placement accuracy, run-out, facet smoothness and choice of suitable materials. LIGA is a combination of deep X-ray lithography, electroplating, and injection molding processes which allow the fabrication of microstructures

Focal Segmental Glomerulosclerosis in Related Miniature Schnauzer Dogs.

Science.gov (United States)

Yau, Wilson; Mausbach, Lisa; Littman, Meryl P; Cianciolo, Rachel E; Brown, Cathy A

2018-03-01

Focal segmental glomerulosclerosis (FSGS) recently has been recognized as a common cause of proteinuria in dogs in general, and in Miniature Schnauzer dogs in particular. This study describes the morphologic features present in the kidneys of 8 related proteinuric Miniature Schnauzer dogs. The FSGS, characterized by solidification of portions of the capillary tuft, affected 32% to 49% of examined glomeruli in these dogs. Synechiae, often accompanied by hyalinosis, were present in 13% to 54% of glomeruli and were more prevalent in older dogs. Seven of 8 dogs had arteriolar hyalinosis. Ultrastructurally, all dogs had evidence of a podocytopathy in the absence of electron-dense deposits, glomerular basement membrane splitting, or fibrils. All dogs had multifocal to extensive podocyte foot process effacement. Other podocyte changes included microvillous transformation, the presence of vacuoles or protein resorption droplets, cytoplasmic electron-dense aggregates, and occasional binucleation. Variable amounts of intraglomerular lipid were present in all dogs. All dogs were proteinuric, with measured values for the urine protein-to-creatinine ratio ranging from 1.2 to 6.5. Azotemia was mild to absent and dogs were euthanatized at 5.1 to 14 years of age, in all cases due to nonrenal diseases. The underlying cause of FSGS in these Miniature Schnauzer dogs has yet to be determined, but contributors likely include genetic podocytopathy, lipid abnormalities, and glomerular hypertension.

‘Amygdala activation and GABAergic gene expression in hippocampal sub-regions at the interplay of stress and spatial learning

Directory of Open Access Journals (Sweden)

Osnat eHadad-Ophir

2014-01-01

Full Text Available Molecular processes in GABAergic local circuit neurons critically contribute to information processing in the hippocampus and to stress-induced activation of the amygdala. In the current study, we determined expression changes in GABA-related factors induced in subregions of the dorsal hippocampus as well as in the BLA of rats 5h after spatial learning in a Morris Water maze, using laser microdissection and quantitative real-time PCR. Spatial learning resulted in highly selective pattern of changes in hippocampal subregions: gene expression levels of neuropeptide Y were reduced in the hilus of the dentate gyrus, whereas somatostatin was increased in the stratum oriens of CA3. The GABA-synthesizing enzymes GAD65 and GAD67 as well as the neuropeptide cholecystokinin were reduced in stratum oriens of CA1. In the BLA, expression of GAD65 and GAD67 were reduced compared to a handled Control group. These expression patterns were further compared to alterations in a group of rats that have been exposed to the water maze but were not provided with an invisible escape platform. In this Water Exposure group, no expression changes were observed in any of the hippocampal subregions, but a differential regulation of all selected target genes was evident in the BLA. These findings suggest that expression changes of GABAergic factors in the hippocampus are associated with spatial learning, while additional stress effects modulate expression alterations in the BLA. Indeed, while in both experimental groups plasma corticosterone levels were enhanced, only Water Exposure stress activated the basolateral amygdala, as indicated by increased levels of phosphorylated ERK1/2. Altered GABAergic function in the BLA may thus contribute to memory consolidation in the hippocampus, in relation to levels of stress and emotionality associated with the experience.

GABAergic Control of Nigrostriatal and Mesolimbic Dopamine in the Rat Brain

Directory of Open Access Journals (Sweden)

Susanne Nikolaus

2018-03-01

Full Text Available Purpose: The present study assessed the effects of the GABAA receptor (R agonist muscimol (MUS, and the GABAAR antagonist bicuculline (BIC on neocortical and subcortical radioligand binding to dopamine D2/3Rs in relation to motor and exploratory behaviors in the rat.Methods: D2/3R binding was measured with small animal SPECT in baseline and after challenge with either 1 mg/kg MUS or 1 mg/kg BIC, using [123I]IBZM as radioligand. Motor/exploratory behaviors were assessed for 30 min in an open field prior to radioligand administration. Anatomical information was gained with a dedicated small animal MRI tomograph. Based on the Paxinos rat brain atlas, regions of interest were defined on SPECT-MRI overlays. Estimations of the binding potentials in baseline and after challenges were obtained by computing ratios of the specifically bound compartments to the cerebellar reference region.Results: After MUS, D2/3R binding was significantly reduced in caudateputamen, nucleus accumbens, thalamus, substania nigra/ventral tegmental area, and posterior hippocampus relative to baseline (0.005 ≤ p ≤ 0.012. In all these areas, except for the thalamus, D2/3R binding was negatively correlated with grooming in the first half and positively correlated with various motor/exploratory behaviors in the second half of the testing session. After BIC, D2/3R binding was significantly elevated in caudateputamen (p = 0.022 and thalamus (p = 0.047 relative to baseline. D2/3R binding in caudateputamen and thalamus was correlated negatively with sitting duration and sitting frequency and positively with motor/exploratory behaviors in the first half of the testing time.Conclusions: Findings indicate direct GABAergic control over nigrostriatal and mesolimbic dopamine levels in relation to behavioral action. This may be of relevance for neuropsychiatric conditions such as anxiety disorder and schizophrenia, which are characterized by both dopaminergic and GABAergic dysfunction.

Optimal and Miniaturized Strongly Coupled Magnetic Resonant Systems

Science.gov (United States)

Hu, Hao

Wireless power transfer (WPT) technologies for communication and recharging devices have recently attracted significant research attention. Conventional WPT systems based either on far-field or near-field coupling cannot provide simultaneously high efficiency and long transfer range. The Strongly Coupled Magnetic Resonance (SCMR) method was introduced recently, and it offers the possibility of transferring power with high efficiency over longer distances. Previous SCMR research has only focused on how to improve its efficiency and range through different methods. However, the study of optimal and miniaturized designs has been limited. In addition, no multiband and broadband SCMR WPT systems have been developed and traditional SCMR systems exhibit narrowband efficiency thereby imposing strict limitations on simultaneous wireless transmission of information and power, which is important for battery-less sensors. Therefore, new SCMR systems that are optimally designed and miniaturized in size will significantly enhance various technologies in many applications. The optimal and miniaturized SCMR systems are studied here. First, analytical models of the Conformal SCMR (CSCMR) system and thorough analysis and design methodology have been presented. This analysis specifically leads to the identification of the optimal design parameters, and predicts the performance of the designed CSCMR system. Second, optimal multiband and broadband CSCMR systems are designed. Two-band, three-band, and four-band CSCMR systems are designed and validated using simulations and measurements. Novel broadband CSCMR systems are also analyzed, designed, simulated and measured. The proposed broadband CSCMR system achieved more than 7 times larger bandwidth compared to the traditional SCMR system at the same frequency. Miniaturization methods of SCMR systems are also explored. Specifically, methods that use printable CSCMR with large capacitors, novel topologies including meandered, SRRs, and

Spontaneous acute spinal subdural hematoma: spontaneous recovery from severe paraparesis--case report and review.

Science.gov (United States)

Payer, Michael; Agosti, Reto

2010-11-01

Spontaneous idiopathic acute spinal subdural hematomas are highly exceptional. Neurological symptoms are usually severe, and rapid diagnosis with MRI is mandatory. Surgical evacuation has frequently been used therapeutically; however, spontaneous recovery in mild cases has also been reported. We present a case of spontaneous recovery from severe paraparesis after spontaneous acute SSDH, and review the English-speaking literature.

Experimental induction of struvite uroliths in miniature schnauzer and beagle dogs.

Science.gov (United States)

Klausner, J S; Osborne, C A; O'Leary, T P; Muscoplat, C M; Griffith, D P

1980-09-01

Urease positive staphylococcal urinary tract infection was experimentally induced in 13 dogs. Eight dogs developed cystic and/or urethral struvite calculi in 2 to 8 weeks. No abnormalities in systemic cell mediated immunity were detected in dogs before or after the establishment of the urinary tract infection. Miniature schnauzers whose ancestors had developed stones seemed to be no more susceptible to experimental urinary tract infection and stone formation than miniature schnauzers or beagles whose ancestors did not develop stones.

A new miniaturized negative-index meta-atom for tri-band applications

Directory of Open Access Journals (Sweden)

Hossain Mohammad Jakir

2017-07-01

Full Text Available In this paper, a miniature negative index meta-atom was designed; simulated, fabricated and measured based on parallel incidence of electromagnetic wave that can maintain a tri-band applications in microwave spectra. Compare to the other multi-band conventional metamaterial, the proposed meta-atom structure allows miniaturization factor and follows better effective medium ratio (EMR. Finite-integration technique (FIT based computer simulation technology (CST electromagnetic simulator was adopted to examine the design of the meta-atom. It exhibits tri-band response in conjunction with backward wave property over a certain frequency band in the microwave regime. Furthermore, the effective medium ratio is considerably improved compared to previously reported metamaterial. Moreover, few parametric analyses were done with the meta-atom. The size, scattering parameters and effective medium parameters of the proposed negative index miniaturized meta-atom is appropriate for tri-band applications.

Miniaturization of high-energy physics detectors. Vol. 14

International Nuclear Information System (INIS)

Stefanini, A.

1983-01-01

Continued experimental research in high-energy physics requires the reduction in size and cost of the advanced technical equipment involved. A new technology is rapidly evolving that promises to replace today's massive high-energy physics instruments--which may be composed of several thousand tons of sensitive parts--with miniaturized equivalents. Smaller, less expensive apparatus would create more opportunities for research worldwide, and many types of experiments now considered impractical could then be carried out. Scientists and engineers from many countries have contributed to this volume to provide a broad panorama of the new miniaturization technology in high-energy physics. They describe a wide range of new instruments and their applications, discuss limitations and technological problems, and explore the connections between technology and progress in the field of high-energy physics

[Local GABA-ergic modulation of serotonergic neuron activity in the nucleus raphe magnus].

Science.gov (United States)

Iniushkin, A N; Merkulova, N A; Orlova, A O; Iniushkina, E M

2009-07-01

In voltage-clamp experimental on slices of the rat brainstem the effects of 5-HT and GABA on serotonergic neurons of nucleus raphe magnus were investigated. Local applications of 5-HT induced an increase in IPCSs frequency and amplitude in 45% of serotonergic cells. The effect suppressed by the blocker of fast sodium channels tetradotoxin. Antagonist of GABA receptor gabazine blocked IPSCs in neurons both sensitive and non-sensitive to 5-HT action. Applications of GABA induced a membrane current (I(GABA)), which was completely blocked by gabazine. The data suggest self-control of the activity of serotonergic neurons in nucleus raphe magnus by negative feedback loop via local GABAergic interneurons.

Subpopulations of somatostatin-immunoreactive nonpyramidal neurons in the amygdala and adjacent external capsule project to the basal forebrain: evidence for the existence of GABAergic projection neurons in the cortical nuclei and basolateral nuclear complex

Directory of Open Access Journals (Sweden)

Alexander J. McDonald

2012-07-01

Full Text Available The hippocampus and amygdala are key structures of the limbic system whose connections include reciprocal interactions with the basal forebrain (BF. The hippocampus receives both cholinergic and GABAergic afferents from the medial septal area of the BF. Hippocampal projections back to the medial septal area arise from nonpyramidal GABAergic neurons that express somatostatin (SOM, calbindin (CB, and neuropeptide Y (NPY. Recent experiments in our lab have demonstrated that the basolateral amygdala, like the hippocampus, receives both cholinergic and GABAergic afferents from the BF. These projections arise from neurons in the substantia innominata and ventral pallidum. It remained to be determined, however, whether the amygdala has projections back to the BF that arise from GABAergic nonpyramidal neurons. This question was investigated in the present study by combining Fluorogold (FG retrograde tract tracing with immunohistochemistry for GABAergic nonpyramidal cell markers, including SOM, CB, NPY, parvalbumin, calretinin, and glutamic acid decarboxylase (GAD. FG injections into the basal forebrain produced a diffuse array of retrogradely labeled neurons in many nuclei of the amygdala. The great majority of amygdalar FG+ neurons did not express nonpyramidal cell markers. However, a subpopulation of nonpyramidal SOM+ neurons, termed long range nonpyramidal neurons (LRNP neurons, in the external capsule, basolateral amygdala, and cortical and medial amygdalar nuclei were FG+. About one-third of the SOM+ LRNP neurons were CB+ or NPY+, and one-half were GAD+. It remains to be determined if these inhibitory amygdalar projections to the BF, like those from the hippocampus, are important for regulating synchronous oscillations in the amygdalar-BF network.

A Miniature Coupled Bistable Vibration Energy Harvester

International Nuclear Information System (INIS)

Zhu, D; Arthur, D C; Beeby, S P

2014-01-01

This paper reports the design and test of a miniature coupled bistable vibration energy harvester. Operation of a bistable structure largely depends on vibration amplitude rather than frequency, which makes it very promising for wideband vibration energy harvesting applications. A coupled bistable structure consists of a pair of mobile magnets that create two potential wells and thus the bistable phenomenon. It requires lower excitation to trigger bistable operation compared to conventional bistable structures. Based on previous research, this work focused on miniaturisation of the coupled bistable structure for energy harvesting application. The proposed bistable energy harvester is a combination of a Duffing's nonlinear structure and a linear assisting resonator. Experimental results show that the output spectrum of the miniature coupled bistable vibration energy harvester was the superposition of several spectra. It had a higher maximum output power and a much greater bandwidth compared to simply the Duffing's structure without the assisting resonator

NMDAR hypofunction and somatostatin-expressing GABAergic interneurons and receptors: A newly identified correlation and its effects in schizophrenia

Directory of Open Access Journals (Sweden)

Fatemah Alherz

2017-06-01

Full Text Available This review investigates the association between N-methyl-d-Aspartate receptor (NMDAR hypofunction and somatostatin-expressing GABAergic interneurons (SST+ and how it contributes to the cognitive deficits observed in schizophrenia (SZ. This is based on evidence that NMDAR antagonists caused symptoms resembling SZ in healthy individuals. NMDAR hypofunction in GABAergic interneurons results in the modulation of the cortical network oscillation, particularly in the gamma range (30–80 Hz. These gamma-band oscillation (GBO abnormalities were found to lead to the cognitive deficits observed in the disorder. Postmortem mRNA studies have shown that SST decreased more significantly than any other biomarker in schizophrenic subjects. The functional role of Somatostatin (SST in the aetiology of SZ can be studied through its receptors. Genetic knockout studies in animal models in Huntington's disease (HD have shown that a specific SST receptor, SSTR2, is increased along with the increased NMDAR activity, with opposing patterns observed in SZ. A direct correlation between SSTR and NMDAR is hence inferred in this review with the hope of finding a potential new therapeutic target for the treatment of SZ and related neurological conditions.

Lamina-specific contribution of glutamatergic and GABAergic potentials to hippocampal sharp wave-ripple complexes.

Science.gov (United States)

Schönberger, Jan; Draguhn, Andreas; Both, Martin

2014-01-01

The mammalian hippocampus expresses highly organized patterns of neuronal activity which form a neuronal correlate of spatial memories. These memory-encoding neuronal ensembles form on top of different network oscillations which entrain neurons in a state- and experience-dependent manner. The mechanisms underlying activation, timing and selection of participating neurons are incompletely understood. Here we studied the synaptic mechanisms underlying one prominent network pattern called sharp wave-ripple complexes (SPW-R) which are involved in memory consolidation during sleep. We recorded SPW-R with extracellular electrodes along the different layers of area CA1 in mouse hippocampal slices. Contribution of glutamatergic excitation and GABAergic inhibition, respectively, was probed by local application of receptor antagonists into s. radiatum, pyramidale and oriens. Laminar profiles of field potentials show that GABAergic potentials contribute substantially to sharp waves and superimposed ripple oscillations in s. pyramidale. Inhibitory inputs to s. pyramidale and s. oriens are crucial for action potential timing by ripple oscillations, as revealed by multiunit-recordings in the pyramidal cell layer. Glutamatergic afferents, on the other hand, contribute to sharp waves in s. radiatum where they also evoke a fast oscillation at ~200 Hz. Surprisingly, field ripples in s. radiatum are slightly slower than ripples in s. pyramidale, resulting in a systematic shift between dendritic and somatic oscillations. This complex interplay between dendritic excitation and perisomatic inhibition may be responsible for the precise timing of discharge probability during the time course of SPW-R. Together, our data illustrate a complementary role of spatially confined excitatory and inhibitory transmission during highly ordered network patterns in the hippocampus.

Alterations of GABAergic Signaling in Autism Spectrum Disorders

Directory of Open Access Journals (Sweden)

Rocco Pizzarelli

2011-01-01

Full Text Available Autism spectrum disorders (ASDs comprise a heterogeneous group of pathological conditions, mainly of genetic origin, characterized by stereotyped behavior, marked impairment in verbal and nonverbal communication, social skills, and cognition. Interestingly, in a small number of cases, ASDs are associated with single mutations in genes encoding for neuroligin-neurexin families. These are adhesion molecules which, by regulating transsynaptic signaling, contribute to maintain a proper excitatory/inhibitory (E/I balance at the network level. Furthermore, GABA, the main inhibitory neurotransmitter in adult life, at late embryonic/early postnatal stages has been shown to depolarize and excite targeted cell through an outwardly directed flux of chloride. The depolarizing action of GABA and associated calcium influx regulate a variety of developmental processes from cell migration and differentiation to synapse formation. Here, we summarize recent data concerning the functional role of GABA in building up and refining neuronal circuits early in development and the molecular mechanisms regulating the E/I balance. A dysfunction of the GABAergic signaling early in development leads to a severe E/I unbalance in neuronal circuits, a condition that may account for some of the behavioral deficits observed in ASD patients.

Naturalism and Mannerism in Indian Miniatures

Science.gov (United States)

Duran, Jane

2001-01-01

In this essay, the author furthers the argument that critical commentary on the Rajput and Muslim miniatures of India has focused on a rather odd use of labels and categories, perhaps to an even greater extent than has been the case with much of the rest of the criticism of the art of South Asia. She first examines the use of the term…

Bend testing for miniature disks

International Nuclear Information System (INIS)

Huang, F.H.; Hamilton, M.L.; Wire, G.L.

1982-01-01

A bend test was developed to obtain ductility measurements on a large number of alloy variants being irradiated in the form of miniature disks. Experimental results were shown to be in agreement with a theoretical analysis of the bend configuration. Disk specimens fabricated from the unstrained grip ends of previously tested tensile specimens were used for calibration purposes; bend ductilities and tensile ductilities were in good agreement. The criterion for estimating ductility was judged acceptable for screening purposes

Miniaturization of Fresnel lenses for solar concentration: a quantitative investigation.

Science.gov (United States)

Duerr, Fabian; Meuret, Youri; Thienpont, Hugo

2010-04-20

Sizing down the dimensions of solar concentrators for photovoltaic applications offers a number of promising advantages. It provides thinner modules and smaller solar cells, which reduces thermal issues. In this work a plane Fresnel lens design is introduced that is first analyzed with geometrical optics. Because of miniaturization, pure ray tracing may no longer be valid to determine the concentration performance. Therefore, a quantitative wave optical analysis of the miniaturization's influence on the obtained concentration performance is presented. This better quantitative understanding of the impact of diffraction in microstructured Fresnel lenses might help to optimize the design of several applications in nonimaging optics.

Bidirectional Signaling of Neuregulin-2 Mediates Formation of GABAergic Synapses and Maturation of Glutamatergic Synapses in Newborn Granule Cells of Postnatal Hippocampus.

Science.gov (United States)

Lee, Kyu-Hee; Lee, Hyunsu; Yang, Che Ho; Ko, Jeong-Soon; Park, Chang-Hwan; Woo, Ran-Sook; Kim, Joo Yeon; Sun, Woong; Kim, Joung-Hun; Ho, Won-Kyung; Lee, Suk-Ho

2015-12-16

Expression of neuregulin-2 (NRG2) is intense in a few regions of the adult brain where neurogenesis persists; however, little is understood about its role in developments of newborn neurons. To study the role of NRG2 in synaptogenesis at different developmental stages, newborn granule cells in rat hippocampal slice cultures were labeled with retrovirus encoding tetracycline-inducible microRNA targeting NRG2 and treated with doxycycline (Dox) at the fourth or seventh postinfection day (dpi). The developmental increase of GABAergic postsynaptic currents (GPSCs) was suppressed by the early Dox treatment (4 dpi), but not by late treatment (7 dpi). The late Dox treatment was used to study the effect of NRG2 depletion specific to excitatory synaptogenesis. The Dox effect on EPSCs emerged 4 d after the impairment in dendritic outgrowth became evident (10 dpi). Notably, Dox treatment abolished the developmental increases of AMPA-receptor mediated EPSCs and the AMPA/NMDA ratio, indicating impaired maturation of glutamatergic synapses. In contrast to GPSCs, Dox effects on EPSCs and dendritic growth were independent of ErbB4 and rescued by concurrent overexpression of NRG2 intracellular domain. These results suggest that forward signaling of NRG2 mediates GABAergic synaptogenesis and its reverse signaling contributes to dendritic outgrowth and maturation of glutamatergic synapses. The hippocampal dentate gyrus is one of special brain regions where neurogenesis persists throughout adulthood. Synaptogenesis is a critical step for newborn neurons to be integrated into preexisting neural network. Because neuregulin-2 (NRG2), a growth factor, is intensely expressed in these regions, we investigated whether it plays a role in synaptogenesis and dendritic growth. We found that NRG2 has dual roles in the development of newborn neurons. For GABAergic synaptogenesis, the extracellular domain of NRG2 acts as a ligand for a receptor on GABAergic neurons. In contrast, its intracellular

Evaluation of a miniature magnetostrictive actuator using Galfenol under tensile stress

International Nuclear Information System (INIS)

Ueno, Toshiyuki; Miura, Hidemitsu; Yamada, Sotoshi

2011-01-01

We are, at present, developing miniature actuators using an iron-gallium alloy (Galfenol). Galfenol is an iron-based magnetostrictive material with magnetostriction exceeding 200 ppm, Young's modulus of 70 GPa and a high relative permeability (>100). The advantages of an actuator using this material are capability of miniaturization, stability against external force, low voltage driving and high power. In this study, a miniature vibrator using an E core of Galfenol under tensile stress up to 20 MPa was investigated. The vibrator did not fracture and maintained the magnetostriction even under a high tensile stress. In addition, the resonance frequency, unchanged under the tensile stress, was lower than the cutoff frequency, hence the vibrator can be driven with a low voltage even in resonance driving. The temperature rise in resonance driving was low and creep was not observed in resonance driving under tensile stress. The vibrator will be applicable in flat panel or bone conductive speakers.

Evaluation of a miniature magnetostrictive actuator using Galfenol under tensile stress

Science.gov (United States)

Ueno, Toshiyuki; Miura, Hidemitsu; Yamada, Sotoshi

2011-02-01

We are, at present, developing miniature actuators using an iron-gallium alloy (Galfenol). Galfenol is an iron-based magnetostrictive material with magnetostriction exceeding 200 ppm, Young's modulus of 70 GPa and a high relative permeability (>100). The advantages of an actuator using this material are capability of miniaturization, stability against external force, low voltage driving and high power. In this study, a miniature vibrator using an E core of Galfenol under tensile stress up to 20 MPa was investigated. The vibrator did not fracture and maintained the magnetostriction even under a high tensile stress. In addition, the resonance frequency, unchanged under the tensile stress, was lower than the cutoff frequency, hence the vibrator can be driven with a low voltage even in resonance driving. The temperature rise in resonance driving was low and creep was not observed in resonance driving under tensile stress. The vibrator will be applicable in flat panel or bone conductive speakers.

Nanoparticle separation with a miniaturized asymmetrical flow field-flow fractionation cartridge

Science.gov (United States)

Müller, David; Cattaneo, Stefano; Meier, Florian; Welz, Roland; deMello, Andrew

2015-07-01

Asymmetrical Flow Field-Flow Fractionation (AF4) is a separation technique applicable to particles over a wide size range. Despite the many advantages of AF4, its adoption in routine particle analysis is somewhat limited by the large footprint of currently available separation cartridges, extended analysis times and significant solvent consumption. To address these issues, we describe the fabrication and characterization of miniaturized AF4 cartridges. Key features of the scale-down platform include simplified cartridge and reagent handling, reduced analysis costs and higher throughput capacities. The separation performance of the miniaturized cartridge is assessed using certified gold and silver nanoparticle standards. Analysis of gold nanoparticle populations indicates shorter analysis times and increased sensitivity compared to conventional AF4 separation schemes. Moreover, nanoparticulate titanium dioxide populations exhibiting broad size distributions are analyzed in a rapid and efficient manner. Finally, the repeatability and reproducibility of the miniaturized platform are investigated with respect to analysis time and separation efficiency.

Miniature scientific-grade magnetic sensors for CubeSats

Science.gov (United States)

Pronenko, Vira; Belyayev, Serhiy

2016-07-01

Micro- and nanosatellites have become more attractive due to their low development and launch cost. A class of nanosatellites defined by the CubeSat standard allows standardizing CubeSat preparation and launch, thus making the projects more affordable. Because of the complexity of sensors miniaturization to install them onboard CubeSat, the majority of CubeSat launches are aimed the technology demonstration or education missions. The scientific success of CubeSat mission depends on the sensors quality. In spite that the sensitivity of the magnetic sensors strongly depends on their size, the recent development in this branch allows us to propose tiny but sensitive both AC and DC magnetometers. The goal of the present report is to introduce the new design of miniature three-component sensors for measurement of vector magnetic fields - for quasi-stationary and slowly fluctuating - flux-gate magnetometer (FGM) - and for alternative ones - search-coil magnetometer (SCM). In order to create magnetometers with the really highest possible level of parameters, a set of scientific and technological problems, mostly aimed at the sensor construction improvement, was solved. The most important parameter characterizing magnetometer quality is its own magnetic noise level (NL). The analysis of the NL influencing factors is made and the ways to decrease it are discussed in the report. Construction details and technical specifications of miniature but sensitive FGM and SCM for the CubeSat mission are presented. This work is supported by EC Framework 7 funded project 607197.

Miniaturized chromatographic radiochemical procedure for 131I - MIBG

International Nuclear Information System (INIS)

Barboza, M.F. de; Pereira, N.S. de; Colturato, M.T.; Silva, C.P.G. da.

1989-12-01

Different solvents were used in paper chromatographic methods to obtain the best system in routine radiochemical control for 131 I-MIBG produced at IPEN-CNEN/SP. The dates were compared with those obtained with eletrophoresis method in buffer acetate, pH=4.5, 350V, during 40 minutes. The stability of the labeled compound store under 4 0 C was studied during 15 days. Miniaturized chromatographic procedures were established using Whatman 3MM (8x1cm) and n-butanol-:acetic acid: water (S:2:1) as a solvent. the Rf values were: 0.3 (I - ) and 1.0 (MIBG). The radiochemical purity was 99.3 and 99.2% (first day) obtained with eletrophoresis and miniaturized chromatographic procedures, respectively and, 84.7% after 15 days of its preparation. It is a rapid, practical and reproductive method. (author) [pt

Miniaturized and reconfigurable notch antenna based on a BST ferroelectric thin film

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Hung Viet [Institut d' Electronique et de Télécommunications de Rennes (IETR), IUT Saint-Brieuc, Université de Rennes 1, 22004 Saint-Brieuc (France); CEA-LETI, Minatec, 17 avenue des Martyrs, 38054 Grenoble Cedex 9 (France); Benzerga, Ratiba, E-mail: ratiba.benzerga@univ-rennes1.fr [Institut d' Electronique et de Télécommunications de Rennes (IETR), IUT Saint-Brieuc, Université de Rennes 1, 22004 Saint-Brieuc (France); Borderon, Caroline [IETR, Université de Nantes, 2 rue de la Houssinière, 44322 Nantes (France); Delaveaud, Christophe [CEA-LETI, Minatec, 17 avenue des Martyrs, 38054 Grenoble Cedex 9 (France); Sharaiha, Ala [Institut d' Electronique et de Télécommunications de Rennes (IETR), IUT Saint-Brieuc, Université de Rennes 1, 22004 Saint-Brieuc (France); Renoud, Raphael [IETR, Université de Nantes, 2 rue de la Houssinière, 44322 Nantes (France); Paven, Claire Le [Institut d' Electronique et de Télécommunications de Rennes (IETR), IUT Saint-Brieuc, Université de Rennes 1, 22004 Saint-Brieuc (France); Pavy, Sabrina; Nadaud, Kevin; Gundel, Hartmut W. [IETR, Université de Nantes, 2 rue de la Houssinière, 44322 Nantes (France)

2015-07-15

Highlights: • A miniature and agile antenna based on a BST MIM capacitor is simulated and made. • Mn{sup 2+} doped BST thin films are synthesized by chemical deposition and spin coating. • Permittivity and losses of the BST thin film are respectively 225 and 0.02 at 1 GHz. • A miniaturization rate of 70% is obtained with a MIM capacitance of 3.7 pF. • A frequency tunability of 14.5% and a tunability performance of 0.04 are measured. - Abstract: This work deals with the design, realization and characterization of a miniature and frequency agile antenna based on a ferroelectric Ba{sub 0,80}Sr{sub 0,20}TiO{sub 3} thin film. The notch antenna is loaded with a variable metal/insulator/metal (MIM) capacitor and is achieved by a monolithic method. The MIM capacitance is 3.7 pF, which results in a resonant frequency of 670 MHz compared to 2.25 GHz for the unloaded simulated antenna; the resulting miniaturization rate is 70%. The characterization of the antenna prototype shows a frequency tunable rate of 14.5% under an electric field of 375 kV/cm, with a tunability performance η = 0.04.

A possible role of the non-GAT1 GABA transporters in transfer of GABA from GABAergic to glutamatergic neurons in mouse cerebellar neuronal cultures

DEFF Research Database (Denmark)

Suñol, C; Babot, Z; Cristòfol, R

2010-01-01

Cultures of dissociated cerebellum from 7-day-old mice were used to investigate the mechanism involved in synthesis and cellular redistribution of GABA in these cultures consisting primarily of glutamatergic granule neurons and a smaller population of GABAergic Golgi and stellate neurons......3 transporters. Only a small population of cells were immuno-stained for GAD while many cells exhibited VGlut-1 like immuno-reactivity which, however, never co-localized with GAD positive neurons. This likely reflects the small number of GABAergic neurons compared to the glutamatergic granule......M concentrations (95%). Essentially all neurons showed GABA like immunostaining albeit with differences in intensity. The results indicate that GABA which is synthesized in a small population of GAD-positive neurons is redistributed to essentially all neurons including the glutamatergic granule cells. GAT1...

Miniature X-ray Tube for Electric Brachytherapy using Carbon Nanotube Field Emitter

International Nuclear Information System (INIS)

Heo, Sung Hwan; Kim, Hyun Jin; Ha, Jun Mok; Cho, Sung Oh

2011-01-01

An electric brachytherapy using a miniature x-ray tube has a major advantage to reduce the x-ray exposure of human body during the cancer radiation therapy by optimal positioning of x-ray radiation source and treatment objectives. In the view of a smaller electronic x-ray source, the CNT field emitter based xray tube can be more minimized than thermionic filament emitter based one because of a simple power supplier connection of cold field emission in diode type as well as a higher electron emission brightness of CNT. This abstract is for introducing the design of a prototype CNT field emitter based miniature x-ray tube. We have vacuum sealed CNT miniature x-ray tube with 7∼10 mm diameter, and characteristics of electron emission and x-ray transportation using MCNP5 code are surveyed

A miniaturized plastic dilution refrigerator

International Nuclear Information System (INIS)

Bindilatti, V.; Oliveira, N.F.Jr.; Martin, R.V.; Frossati, G.

1996-01-01

We have built and tested a miniaturized dilution refrigerator, completely contained (still, heat exchanger and mixing chamber) inside a plastic (PVC) tube of 10 mm diameter and 170 mm length. With a 25 cm 2 CuNi heat exchanger, it reached temperatures below 50 mK, for circulation rates below 70 μmol/s. The cooling power at 100 mK and 63 μmol/s was 45 μW. The experimental space could accommodate samples up to 6 mm in diameter. (author)

A molecular diagnostic test for persistent Müllerian duct syndrome in miniature schnauzer dogs.

Science.gov (United States)

Pujar, S; Meyers-Wallen, V N

2009-01-01

In persistent Müllerian duct syndrome (PMDS), Müllerian ducts fail to regress in males during sexual differentiation. In the canine miniature schnauzer model, PMDS is caused by a C to T transition in exon 3 of the Müllerian inhibiting substance type II receptor (MISRII), which introduces a DdeI restriction site. Here we report a molecular diagnostic test for PMDS in the miniature schnauzer to identify affected dogs and carriers. As our test results suggest that the mutation is identical by descent in affected dogs of this breed, the test could be used to eliminate this mutation from the miniature schnauzer breed worldwide.

Maxillary bone epithelial cyst in an adult miniature schnauzer.

Science.gov (United States)

Lin, Chung-Tien; Tasi, Wen-Chih; Hu, Chun-Kun; Lin, Nien-Ting; Huang, Pei-Yun; Yeh, Lih-Seng

2008-09-01

Maxillary bone epithelial cyst is rare in dogs. A 5-year-old, spayed female miniature schnauzer developed a swelling below the nasal canthus of left eye. Plain radiograph demonstrated a 1.5 cm diameter of radiolucent lesion on the maxillary bone anteroventral to the eye, and contrast dacryocystorhinography confirmed an obstructed nasolarcrimal duct. The swelling showed poor response to antibiotic treatment but responded well to oral prednisolone. Exploratory surgery revealed a cyst-like structure filled with brown serous fluid. Histopathological examination of the removed cyst revealed a double cuboidal epithelial cyst. The dog recovered rapidly after surgery, and the swelling had not recurred for a 36-month follow-up. It is the first case of periorbital bone epithelial cyst reported in an adult miniature schnauzer.

Miniaturizing EM Sample Preparation: Opportunities, Challenges, and "Visual Proteomics".

Science.gov (United States)

Arnold, Stefan A; Müller, Shirley A; Schmidli, Claudio; Syntychaki, Anastasia; Rima, Luca; Chami, Mohamed; Stahlberg, Henning; Goldie, Kenneth N; Braun, Thomas

2018-03-01

This review compares and discusses conventional versus miniaturized specimen preparation methods for transmission electron microscopy (TEM). The progress brought by direct electron detector cameras, software developments and automation have transformed transmission cryo-electron microscopy (cryo-EM) and made it an invaluable high-resolution structural analysis tool. In contrast, EM specimen preparation has seen very little progress in the last decades and is now one of the main bottlenecks in cryo-EM. Here, we discuss the challenges faced by specimen preparation for single particle EM, highlight current developments, and show the opportunities resulting from the advanced miniaturized and microfluidic sample grid preparation methods described, such as visual proteomics and time-resolved cryo-EM studies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Miniature Reaction Wheel for Small Satellite Control, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The overall goal of this project is to design, develop, demonstrate, and deliver a miniature, high torque, low-vibration reaction wheel for use on small satellites....

Activation of GABAergic pathway by hypocretin in the median raphe nucleus (MRN) mediates stress-induced theta rhythm in rats.

Science.gov (United States)

Hsiao, Yi-Tse; Jou, Shuo-Bin; Yi, Pei-Lu; Chang, Fang-Chia

2012-07-15

The frequency of electroencephalograms (EEGs) is predominant in theta rhythm during stress (e.g., footshock) in rats. Median raphe nucleus (MRN) desynchronizes hippocampal theta waves via activation of GABAergic neurons in the medial septum-diagonal band of Broca (MS-DBB), a theta rhythm pacemaker. Increased hypocretin mediates stress responses in addition to the maintenance of wakefulness. Hypocretin receptors are abundant in the MRN, suggesting a possible role of hypocretin in modulating stress-induced theta rhythm. Our results indicated that the intensity of theta waves was enhanced by footshock and that a hypocretin receptor antagonist (TCS1102) suppressed the footshock-induced theta waves. Administration of hypocretin-1 (1 and 10 μg) and hypocretin-2 (10 μg) directly into the MRN simulated the effect of footshock and significantly increased theta waves. Co-administration of GABA(A) receptor antagonist, bicuculline, into the MRN blocked the increase of theta waves induced by hypocretins or footshock. These results suggested that stress enhances the release of hypocretins, activates GABAergic neurons in the MRN, blocks the ability of MRN to desynchronize theta waves, and subsequently increases the intensity of theta rhythm. Copyright © 2012 Elsevier B.V. All rights reserved.

Inhibition of GABAergic Neurotransmission by HIV-1 Tat and Opioid Treatment in the Striatum Involves ?-Opioid Receptors

OpenAIRE

Xu, Changqing; Fitting, Sylvia

2016-01-01

Due to combined antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) is considered a chronic disease with high prevalence of mild forms of neurocognitive impairments, also referred to as HIV-associated neurocognitive disorders (HAND). Although opiate drug use can exacerbate HIV-1 Tat-induced neuronal damage, it remains unknown how and to what extent opioids interact with Tat on the GABAergic system. We conducted whole-cell recordings in mouse striatal slices and examined...

Miniature, mobile X-ray computed radiography system

Science.gov (United States)

Watson, Scott A; Rose, Evan A

2017-03-07

A miniature, portable x-ray system may be configured to scan images stored on a phosphor. A flash circuit may be configured to project red light onto a phosphor and receive blue light from the phosphor. A digital monochrome camera may be configured to receive the blue light to capture an article near the phosphor.

The MIT miniaturized disk bend test

International Nuclear Information System (INIS)

Harling, O.K.; Lee, M.; Sohn, D.S.; Kohse, G.; Lau, C.W.

1983-01-01

A miniaturized disk bend test (MDBT) using transmission electron microscopy specimens for the determination of various mechanical properties is being developed at MIT. Recent progress in obtaining strengths and ductilities of highly irradiated metal alloys is reviewed. Possibilities exist for applying the MDBT approach to the determination of other mechanical properties. Progress in fatigue testing and in determination of the ductile-to-brittle transition temperature is reviewed briefly

Miniature magnetic fluid seal working in liquid environments

Science.gov (United States)

Mitamura, Yoshinori; Durst, Christopher A.

2017-06-01

This study was carried out to develop a miniature magnetic fluid (MF) seal working in a liquid environment. The miniature MF seal is intended for use in a catheter blood pump. The requirements for the MF seal included a size of less than Ø4×4.5 mm, shaft diameter of 1 mm, sealing pressure of 200 mmHg, shaft speed of up to 40000 rpm, and life of one month. The miniature MF seal was composed of an NdFeB magnet (Ø4×Ø2×1) sandwiched between two pole pieces (Ø4×Ø1.1×0.5). A shield (Ø4×Ø1.2×1.5) was placed on the pole piece facing the liquid to minimize the influence of pump flow on the MF. The seal was installed on a Ø1 shaft. A seal was formed by injecting MF (Ms: 47.8 kA/m and η: 0.5 Pa·sec) into the gap between the pole pieces and the shaft. Total volume of the MF seal was 44 μL. A sealing pressure of 370 mmHg was obtained at motor speeds of 0-40,000 rpm. The seal remained perfect for 10 days in saline under the condition of a pump flow of 1.5 L/min (The test was terminated in accordance with plans). The seal remained intact after ethylene oxide sterilization during which the seal was exposed to high pressures. In conclusion, the newly developed MF seal will be useful for a catheter pump.

Spontaneous external gallbladder perforation

International Nuclear Information System (INIS)

Noeldge, G.; Wimmer, B.; Kirchner, R.

1981-01-01

Spontaneous perforation of the gallbladder is one complication of cholelithiasis. There is a greater occurence of free perforation in the peritoneal cavity with bilary pertonitis, followed by the perforation into the stomach, small intestine and colon. A single case of the nowadays rare spontaneous perforation in and through the abdominal wall will be reported. Spontaneous gallbladder perforation appears nearly asymptomatic in its clinical course because of absent biliary peritonitis. (orig.) [de

Pinching evidences in a miniature plasma focus with fast pseudospark switch

International Nuclear Information System (INIS)

Hassan, S M; Zhang, T; Patran, A; Rawat, R S; Springham, S V; Tan, T L; Wong, D; Wang, W; Lee, S; Gribkov, V A; Mohanty, S R; Lee, P

2006-01-01

We report the observations of pinching in a miniature plasma focus (PF) (58-160 J) operated in repetitive mode using fast pseudospark switch (PSS). The size of the device, which includes the capacitor bank, PSS and the focus chamber, is of the order of 22 cm x 22 cm x 38 cm. Several diagnostic tools, the gated imager, streak camera, current and voltage probe, are employed simultaneously to confirm the occurrence of pinching in this fast miniature PF device. The device is optimized for operation in neon and hydrogen as the working gas. The best focus formation was obtained at pressures between 0.5 to 8.0 mbar for neon and between 7.0 to 15.0 mbar for hydrogen. When the system was operated at 100 J with hydrogen as the filling gas, the typical dip in the current derivative signal and the typical peak in the voltage signal associated with pinch compression, are observed to be most intense indicating efficient pinching in the miniature PF device

Current applications of miniaturized chromatographic and electrophoretic techniques in drug analysis.

Science.gov (United States)

Aturki, Zeineb; Rocco, Anna; Rocchi, Silvia; Fanali, Salvatore

2014-12-01

In the last decade, miniaturized separation techniques have become greatly popular in pharmaceutical analysis. Miniaturized separation methods are increasingly utilized in all processes of drug discovery as well as quality control of pharmaceutical preparation. The great advantages presented by the analytical miniaturized techniques, including high separation efficiency and resolution, rapid analysis and minimal consumption of reagents and samples, make them an attractive alternative to the conventional chromatographic methods for drug analysis. The purpose of this review is to give a general overview of the applicability of capillary electrophoresis (CE), capillary electrochromatography (CEC) and micro/capillary/nano-liquid chromatography (micro-LC/CLC/nano-LC) for the analysis of pharmaceutical formulations, active pharmaceutical ingredients (API), drug impurity testing, chiral drug separation, determination of drugs and metabolites in biological fluids. The results concerning the use of CEC, micro-LC, CLC, and nano-LC in the period 2009-2013, while for CE, those from 2012 up to the review draft are here summarized and some specific examples are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Clarified Açaí (Euterpe oleracea Juice as an Anticonvulsant Agent: In Vitro Mechanistic Study of GABAergic Targets

Directory of Open Access Journals (Sweden)

Gabriela P. F. Arrifano

2018-01-01

Full Text Available Seizures affect about 50 million people around the world. Approximately 30% of seizures are refractory to the current pharmacological arsenal, so, the pursuit of new therapeutic alternatives is essential. Clarified Euterpe oleracea (EO juice showed anticonvulsant properties similar to diazepam in an in vivo model with pentylenetetrazol, a GABAA receptor blocker. This study investigated the effects of EO on the main GABAergic targets for anticonvulsant drugs, analyzing the effect on the GABA receptor’s benzodiazepine and picrotoxinin binding sites and the GABA uptake. Primary cultures of cortical neurons and astrocytes were treated with EO (0–25% for up to 90 min. [3H]Flunitrazepam and [3H]TBOB binding, [3H]GABA uptake, cell viability, and morphology were assayed. Nonlethal concentrations of EO increased agonist binding and decreased antagonist binding in cortical neurons. Low concentrations significantly inhibited GABA uptake, especially in astrocytes, suggesting an accumulation of endogenous GABA in the synaptic cleft. The results demonstrate, for the first time, that EO can improve GABAergic neurotransmission via interactions with GABAA receptor and modulation of GABA uptake. Understanding these molecular mechanisms will help in the treatment of seizures and epilepsy, especially in developing countries where geographic isolation and low purchasing power are the main barriers to access to adequate treatment.

A Miniature Data Repository on a Raspberry Pi

NARCIS (Netherlands)

Samourkasidis, Argyrios; Athanasiadis, Ioannis N.

2017-01-01

This work demonstrates a low-cost, miniature data repository proof-of-concept. Such a system needs to be resilient to power and network failures, and expose adequate processing power for persistent, long-term storage. Additional services are required for interoperable data sharing and visualization.

A comparative perspective on minicolumns and inhibitory GABAergic interneurons in the neocortex

Directory of Open Access Journals (Sweden)

Mary Ann Raghanti

2010-02-01

Full Text Available Neocortical columns are functional and morphological units whose architecture may have been under selective evolutionary pressure in different mammalian lineages in response to encephalization and specializations of cognitive abilities. Inhibitory interneurons make a substantial contribution to the morphology and distribution of minicolumns within the cortex. In this context, we review differences in minicolumns and GABAergic interneurons among species and discuss possible implications for signaling among and within minicolumns. Furthermore, we discuss how abnormalities of both minicolumn disposition and inhibitory interneurons might be associated with neuropathological processes, such as Alzheimer’s disease, autism, and schizophrenia. Specifically, we will explore the possibility that phylogenetic variability in calcium-binding protein-expressing interneuron subtypes is directly related to differences in minicolumn morphology among species and might contribute to neuropathological susceptibility in humans.

Lightweight, Miniature Inertial Measurement System

Science.gov (United States)

Tang, Liang; Crassidis, Agamemnon

2012-01-01

A miniature, lighter-weight, and highly accurate inertial navigation system (INS) is coupled with GPS receivers to provide stable and highly accurate positioning, attitude, and inertial measurements while being subjected to highly dynamic maneuvers. In contrast to conventional methods that use extensive, groundbased, real-time tracking and control units that are expensive, large, and require excessive amounts of power to operate, this method focuses on the development of an estimator that makes use of a low-cost, miniature accelerometer array fused with traditional measurement systems and GPS. Through the use of a position tracking estimation algorithm, onboard accelerometers are numerically integrated and transformed using attitude information to obtain an estimate of position in the inertial frame. Position and velocity estimates are subject to drift due to accelerometer sensor bias and high vibration over time, and so require the integration with GPS information using a Kalman filter to provide highly accurate and reliable inertial tracking estimations. The method implemented here uses the local gravitational field vector. Upon determining the location of the local gravitational field vector relative to two consecutive sensors, the orientation of the device may then be estimated, and the attitude determined. Improved attitude estimates further enhance the inertial position estimates. The device can be powered either by batteries, or by the power source onboard its target platforms. A DB9 port provides the I/O to external systems, and the device is designed to be mounted in a waterproof case for all-weather conditions.

Flight experience with lightweight, low-power miniaturized instrumentation systems

Science.gov (United States)

Hamory, Philip J.; Murray, James E.

1992-01-01

Engineers at the NASA Dryden Flight Research Facility (NASA-Dryden) have conducted two flight research programs with lightweight, low-power miniaturized instrumentation systems built around commercial data loggers. One program quantified the performance of a radio-controlled model airplane. The other program was a laminar boundary-layer transition experiment on a manned sailplane. The purpose of this paper is to report NASA-Dryden personnel's flight experience with the miniaturized instrumentation systems used on these two programs. The paper will describe the data loggers, the sensors, and the hardware and software developed to complete the systems. The paper also describes how the systems were used and covers the challenges encountered to make them work. Examples of raw data and derived results will be shown as well. Finally, future plans for these systems will be discussed.

Rad-Hard, Miniaturized, Scalable, High-Voltage Switching Module for Power Applications Rad-Hard, Miniaturized

Science.gov (United States)

Adell, Philippe C.; Mojarradi, Mohammad; DelCastillo, Linda Y.; Vo, Tuan A.

2011-01-01

A paper discusses the successful development of a miniaturized radiation hardened high-voltage switching module operating at 2.5 kV suitable for space application. The high-voltage architecture was designed, fabricated, and tested using a commercial process that uses a unique combination of 0.25 micrometer CMOS (complementary metal oxide semiconductor) transistors and high-voltage lateral DMOS (diffusion metal oxide semiconductor) device with high breakdown voltage (greater than 650 V). The high-voltage requirements are achieved by stacking a number of DMOS devices within one module, while two modules can be placed in series to achieve higher voltages. Besides the high-voltage requirements, a second generation prototype is currently being developed to provide improved switching capabilities (rise time and fall time for full range of target voltages and currents), the ability to scale the output voltage to a desired value with good accuracy (few percent) up to 10 kV, to cover a wide range of high-voltage applications. In addition, to ensure miniaturization, long life, and high reliability, the assemblies will require intensive high-voltage electrostatic modeling (optimized E-field distribution throughout the module) to complete the proposed packaging approach and test the applicability of using advanced materials in a space-like environment (temperature and pressure) to help prevent potential arcing and corona due to high field regions. Finally, a single-event effect evaluation would have to be performed and single-event mitigation methods implemented at the design and system level or developed to ensure complete radiation hardness of the module.

Definition of spontaneous reconnection

International Nuclear Information System (INIS)

Schindler, K.

1984-01-01

The author discusses his view of driven versus spontaneous. There is a close link between ''spontaneous'' and ''instability.'' One of the prominent examples for instability is the thermal convection instability. Just to remind you, if you heat a fluid layer from below, it takes a certain Rayleigh number to make it unstable. Beyond the onset point you find qualitatively new features. That is called ''spontaneous,'' and this is a bit more than semantics. It's a new qualitative property that appears and it is spontaneous although we have an energy flux through the system. It's a misconception, to call this ''driven'' pointing at the energy flux through it. Of course, the convection would not exist without this energy flux. But what makes it ''spontaneous'' is that without any particular external signal, a new qualitative feature appears. And this is what is called an ''instability'' and ''spontaneous.'' From these considerations the author got a little reassured of what distinction should be made in the field of the magnetosphere. If we have a smooth energy transport into the magnetosphere and suddenly we have this qualitatively new feature (change of B-topology) coming up; then, using this terminology we don't have a choice other than calling this spontaneous or unstable, if you like. If we ''tell'' the system where it should make its neutral line and where it should make its plasmoids, then, it is driven. And this provides a very clear-cut observational distinction. The author emphasizes the difference he sees is a qualitative difference, not only a quantitative one

Miniature rainbow schlieren deflectometry system for quantitative measurements in microjets and flames

International Nuclear Information System (INIS)

Satti, Rajani P.; Kolhe, Pankaj S.; Olcmen, Semih; Agrawal, Ajay K.

2007-01-01

Recent interest in small-scale flow devices has created the need for miniature instruments capable of measuring scalar flow properties with high spatial resolution. We present a miniature rainbow schlieren deflectometry system to nonintrusively obtain quantitative species concentration and temperature data across the whole field. The optical layout of the miniature system is similar to that of a macroscale system, although the field of view is smaller by an order of magnitude. Employing achromatic lenses and a CCD array together with a camera lens and extension tubes, we achieved spatial resolution down to 4 μm. Quantitative measurements required a careful evaluation of the optical components. The capability of the system is demonstrated by obtaining concentration measurements in a helium microjet (diameter, d=650 μm) and temperature and concentration measurements in a hydrogen jet diffusion flame from a microinjector(d=50 μm). Further, the flow field of underexpanded nitrogen jets is visualized to reveal details of the shock structures existing downstream of the jet exit

Ambiguous genitalia in a fertile, unilaterally cryptorchid male miniature schnauzer dog.

Science.gov (United States)

Breshears, M A; Peters, J L

2011-09-01

A 7-year-old male miniature schnauzer dog with unilateral cryptorchidism was presented for elective orchiectomy. Surgery to remove the cryptorchid testis revealed a fully formed uterus with horns attached to both testis and the body and cervix terminating at the prostate gland. The gross and microscopic diagnosis for the genital tract was persistent Müllerian duct syndrome with unilateral cryptorchidism. Additional associated lesions included cystic endometrial hyperplasia and a solitary, intratubular seminoma within the undescended testis. Persistent Müllerian duct syndrome is rare among domestic animals but is more common in miniature schnauzer dogs because of inheritance as an autosomal recessive trait.

Chronic alcohol exposure disrupts CB₁ regulation of GABAergic transmission in the rat basolateral amygdala

DEFF Research Database (Denmark)

Varodayan, Florence P.; Bajo, Michal; Soni, Neeraj

2017-01-01

in BLA pyramidal neurons of rats exposed to 2–3 weeks intermittent ethanol. In the naïve rat BLA, the CB1 agonist WIN 55,212-2 (WIN) decreased GABA release, and this effect was prevented by the CB1 antagonist AM251. AM251 alone increased GABA release via a mechanism requiring postsynaptic calcium-dependent......1 influence on BLA GABAergic transmission that is dysregulated by chronic ethanol exposure and, thus, may contribute to the alcohol-dependent state....

Hereditary esophageal dysfunction in the Miniature Schnauzer dog.

Science.gov (United States)

Cox, V S; Wallace, L J; Anderson, V E; Rushmer, R A

1980-03-01

Miniature Schnauzers maintained in a colony for 9 years were used to study the inheritance of esophageal dysfunction (canine achalasia, megaesophagus). All dogs were evaluated radiographically, using a barium swallow contrast technique which clearly distinguished normal and affected pups. At 4 to 6 months of age, all affected dogs had recovered clinically except one, and radiographic evidence of dysfunction was markedly diminished. None of the affected dogs required a special feeding regimen. Analysis of breeding pairs revealed a ratio of 9 affected/11 normal dogs when an affected male was mated with a normal female, and a 13/3 ratio was observed when two affected dogs were mated. These ratios were compatible with a simple autosomal dominant or a 60% penetrance autosomal-recessive mode of inheritance. Outbreeding to an affected Miniature Schnauzer/Poodle crossbred dog resulted in only two of 30 affected pups, indicating a polygenic mode of inheritance in outbred populations.

Digital intelligent booster for DCC miniature train networks

Science.gov (United States)

Ursu, M. P.; Condruz, D. A.

2017-08-01

Modern miniature trains are now driven by means of the DCC (Digital Command and Control) system, which allows the human operator or a personal computer to launch commands to each individual train or even to control different features of the same train. The digital command station encodes these commands and sends them to the trains by means of electrical pulses via the rails of the railway network. Due to the development of the miniature railway network, it may happen that the power requirement of the increasing number of digital locomotives, carriages and accessories exceeds the nominal output power of the digital command station. This digital intelligent booster relieves the digital command station from powering the entire railway network all by itself, and it automatically handles the multiple powered sections of the network. This electronic device is also able to detect and process short-circuits and overload conditions, without the intervention of the digital command station.

Adventitious shoot regeneration from leaf explants of miniature paprika

African Journals Online (AJOL)

STORAGESEVER

2010-05-10

May 10, 2010 ... products, Capsicum spp. shows high levels of cross pollination ... Composition of a nutrient solution used for the culture of miniature paprika in the greenhouse. ... Yellow' were obtained from Seminis Korea Inc. Seeds were.

Movement recognition technology as a method of assessing spontaneous general movements in high risk infants

Directory of Open Access Journals (Sweden)

Claire eMarcroft

2015-01-01

Full Text Available Preterm birth is associated with increased risks of neurological and motor impairments such as cerebral palsy. The risks are highest in those born at the lowest gestations. Early identification of those most at risk is challenging meaning that a critical window of opportunity to improve outcomes through therapy-based interventions may be missed. Clinically, the assessment of spontaneous general movements is an important tool which can be used for the prediction of movement impairments in high risk infants.Movement recognition aims to capture and analyze relevant limb movements through computerized approaches focusing on continuous, objective, and quantitative assessment. Different methods of recording and analyzing infant movements have recently been explored in high risk infants. These range from camera-based solutions to body-worn miniaturized movement sensors used to record continuous time-series data that represent the dynamics of limb movements. Various machine learning methods have been developed and applied to the analysis of the recorded movement data. This analysis has focused on the detection and classification of atypical spontaneous general movements. This paper aims to identify recent translational studies using movement recognition technology as a method of assessing movement in high risk infants. The application of this technology within pediatric practice represents a growing area of inter-disciplinary collaboration which may lead to a greater understanding of the development of the nervous system in infants at high risk of motor impairment.

Miniature linear cooler development

International Nuclear Information System (INIS)

Pruitt, G.R.

1993-01-01

An overview is presented of the status of a family of miniature linear coolers currently under development by Hughes Aircraft Co. for use in hand held, volume limited or power limited infrared applications. These coolers, representing the latest additions to the Hughes family of TOP trademark [twin-opposed piston] linear coolers, have been fabricated and tested in three different configurations. Each configuration is designed to utilize a common compressor assembly resulting in reduced manufacturing costs. The baseline compressor has been integrated with two different expander configurations and has been operated with two different levels of input power. These various configuration combinations offer a wide range of performance and interface characteristics which may be tailored to applications requiring limited power and size without significantly compromising cooler capacity or cooldown characteristics. Key cooler characteristics and test data are summarized for three combinations of cooler configurations which are representative of the versatility of this linear cooler design. Configurations reviewed include the shortened coldfinger [1.50 to 1.75 inches long], limited input power [less than 17 Watts] for low power availability applications; the shortened coldfinger with higher input power for lightweight, higher performance applications; and coldfingers compatible with DoD 0.4 Watt Common Module coolers for wider range retrofit capability. Typical weight of these miniature linear coolers is less than 500 grams for the compressor, expander and interconnecting transfer line. Cooling capacity at 80K at room ambient conditions ranges from 400 mW to greater than 550 mW. Steady state power requirements for maintaining a heat load of 150 mW at 80K has been shown to be less than 8 Watts. Ongoing reliability growth testing is summarized including a review of the latest test article results

Biometry and clinical characteristics of congenital cataracts and microphthalmia in the Miniature Schnauzer.

Science.gov (United States)

Gelatt, K N; Samuelson, D A; Barrie, K P; Das, N D; Wolf, E D; Bauer, J E; Andresen, T L

1983-07-01

Forty-two Miniature Schnauzer pups and adults with congenital cataracts and microphthalmia were evaluated by serial ophthalmic examinations, slit lamp biomicroscopic photography, and A-scan ultrasonography. The cataracts were evident when the eyelids opened at 2 weeks, affecting predominantly the lens nucleus and posterior cortex. Lenticonus was evident in 19% of the cataractous lenses. Progression of the cataracts was variable and related to involvement of the equatorial and posterior cortices. Lens-induced uveitis developed in some adult dogs with advanced hypermature cataracts. The globe and lens were smaller than normal in the cataractous eyes, as ascertained by A-scan ultrasonography. Age-matched comparisons of clear lens carrier Miniature Schnauzers and normal Beagles with the cataractous Miniature Schnauzers indicated affected globes and cataractous lenses were reduced 10% to 20% in their anteroposterior lengths. The microphthalmia appeared related to the congenital microphakic cataract.

The Relevance of AgRP Neuron-Derived GABA Inputs to POMC Neurons Differs for Spontaneous and Evoked Release.

Science.gov (United States)

Rau, Andrew R; Hentges, Shane T

2017-08-02

Hypothalamic agouti-related peptide (AgRP) neurons potently stimulate food intake, whereas proopiomelanocortin (POMC) neurons inhibit feeding. Whether AgRP neurons exert their orexigenic actions, at least in part, by inhibiting anorexigenic POMC neurons remains unclear. Here, the connectivity between GABA-releasing AgRP neurons and POMC neurons was examined in brain slices from male and female mice. GABA-mediated spontaneous IPSCs (sIPSCs) in POMC neurons were unaffected by disturbing GABA release from AgRP neurons either by cell type-specific deletion of the vesicular GABA transporter or by expression of botulinum toxin in AgRP neurons to prevent vesicle-associated membrane protein 2-dependent vesicle fusion. Additionally, there was no difference in the ability of μ-opioid receptor (MOR) agonists to inhibit sIPSCs in POMC neurons when MORs were deleted from AgRP neurons, and activation of the inhibitory designer receptor hM4Di on AgRP neurons did not affect sIPSCs recorded from POMC neurons. These approaches collectively indicate that AgRP neurons do not significantly contribute to the strong spontaneous GABA input to POMC neurons. Despite these observations, optogenetic stimulation of AgRP neurons reliably produced evoked IPSCs in POMC neurons, leading to the inhibition of POMC neuron firing. Thus, AgRP neurons can potently affect POMC neuron function without contributing a significant source of spontaneous GABA input to POMC neurons. Together, these results indicate that the relevance of GABAergic inputs from AgRP to POMC neurons is state dependent and highlight the need to consider different types of transmitter release in circuit mapping and physiologic regulation. SIGNIFICANCE STATEMENT Agouti-related peptide (AgRP) neurons play an important role in driving food intake, while proopiomelanocortin (POMC) neurons inhibit feeding. Despite the importance of these two well characterized neuron types in maintaining metabolic homeostasis, communication between these

Miniaturization of components and systems for space using MEMS-technology

Science.gov (United States)

Grönland, Tor-Arne; Rangsten, Pelle; Nese, Martin; Lang, Martin

2007-06-01

Development of MEMS-based (micro electro mechanical system) components and subsystems for space applications has been pursued by various research groups and organizations around the world for at least two decades. The main driver for developing MEMS-based components for space is the miniaturization that can be achieved. Miniaturization can not only save orders of magnitude in mass and volume of individual components, but it can also allow increased redundancy, and enable novel spacecraft designs and mission scenarios. However, the commercial breakthrough of MEMS has not occurred within the space business as it has within other branches such as the IT/telecom or automotive industries, or as it has in biotech or life science applications. A main explanation to this is the highly conservative attitude to new technology within the space community. This conservatism is in many senses motivated by a very low risk acceptance in the few and costly space projects that actually ends with a space flight. To overcome this threshold there is a strong need for flight opportunities where reasonable risks can be accepted. Currently there are a few flight opportunities allowing extensive use of new technology in space, but one of the exceptions is the PRISMA program. PRISMA is an international (Sweden, Germany, France, Denmark, Norway, Greece) technology demonstration program with focus on rendezvous and formation flying. It is a two satellite LEO mission with a launch scheduled for the first half of 2009. On PRISMA, a number of novel technologies e.g. RF metrology sensor for Darwin, autonomous formation flying based on GPS and vision-based sensors, ADN-based "green propulsion" will be demonstrated in space for the first time. One of the satellites will also have a miniaturized propulsion system onboard based on MEMS-technology. This novel propulsion system includes two microthruster modules, each including four thrusters with micro- to milli-Newton thrust capability. The novelty

Miniature shock tube for laser driven shocks.

Science.gov (United States)

Busquet, Michel; Barroso, Patrice; Melse, Thierry; Bauduin, Daniel

2010-02-01

We describe in this paper the design of a miniature shock tube (smaller than 1 cm(3)) that can be placed in a vacuum vessel and allows transverse optical probing and longitudinal backside extreme ultraviolet emission spectroscopy in the 100-500 A range. Typical application is the study of laser launched radiative shocks, in the framework of what is called "laboratory astrophysics."

A Miniaturized Optical Sensor with Integrated Gas Cell

NARCIS (Netherlands)

Ayerden, N.P.; Ghaderi, M.; De Graaf, G.; Wolffenbuttel, R.F.

2015-01-01

The design, fabrication and characterization of a highly integrated optical gas sensor is presented. The gas cell takes up most of the space in a microspectrometer and is the only component that has so far not been miniaturized. Using the tapered resonator cavity of a linear variable optical filter

Recombinant drugs-on-a-chip: The usage of capillary electrophoresis and trends in miniaturized systems – A review

Energy Technology Data Exchange (ETDEWEB)

Morbioli, Giorgio Gianini; Mazzu-Nascimento, Thiago; Aquino, Adriano [Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense, 400, 13566-590 São Carlos, SP (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP (Brazil); Cervantes, Cesar [Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense, 400, 13566-590 São Carlos, SP (Brazil); Carrilho, Emanuel, E-mail: emanuel@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense, 400, 13566-590 São Carlos, SP (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP (Brazil)

2016-09-07

We present here a critical review covering conventional analytical tools of recombinant drug analysis and discuss their evolution towards miniaturized systems foreseeing a possible unique recombinant drug-on-a-chip device. Recombinant protein drugs and/or pro-drug analysis require sensitive and reproducible analytical techniques for quality control to ensure safety and efficacy of drugs according to regulatory agencies. The versatility of miniaturized systems combined with their low-cost could become a major trend in recombinant drugs and bioprocess analysis. Miniaturized systems are capable of performing conventional analytical and proteomic tasks, allowing for interfaces with other powerful techniques, such as mass spectrometry. Microdevices can be applied during the different stages of recombinant drug processing, such as gene isolation, DNA amplification, cell culture, protein expression, protein separation, and analysis. In addition, organs-on-chips have appeared as a viable alternative to testing biodrug pharmacokinetics and pharmacodynamics, demonstrating the capabilities of the miniaturized systems. The integration of individual established microfluidic operations and analytical tools in a single device is a challenge to be overcome to achieve a unique recombinant drug-on-a-chip device. - Highlights: • Principal analytical tools for analysis of recombinant drugs are presented. • A critical comparison among different substrates for fabrication of miniaturized systems is made. • Applications of miniaturized systems to produce recombinant drugs are shown. • Future trends of miniaturized systems capable of integrating analytical and proteomic tools in a single device are envisioned.

Recombinant drugs-on-a-chip: The usage of capillary electrophoresis and trends in miniaturized systems – A review

International Nuclear Information System (INIS)

Morbioli, Giorgio Gianini; Mazzu-Nascimento, Thiago; Aquino, Adriano; Cervantes, Cesar; Carrilho, Emanuel

2016-01-01

We present here a critical review covering conventional analytical tools of recombinant drug analysis and discuss their evolution towards miniaturized systems foreseeing a possible unique recombinant drug-on-a-chip device. Recombinant protein drugs and/or pro-drug analysis require sensitive and reproducible analytical techniques for quality control to ensure safety and efficacy of drugs according to regulatory agencies. The versatility of miniaturized systems combined with their low-cost could become a major trend in recombinant drugs and bioprocess analysis. Miniaturized systems are capable of performing conventional analytical and proteomic tasks, allowing for interfaces with other powerful techniques, such as mass spectrometry. Microdevices can be applied during the different stages of recombinant drug processing, such as gene isolation, DNA amplification, cell culture, protein expression, protein separation, and analysis. In addition, organs-on-chips have appeared as a viable alternative to testing biodrug pharmacokinetics and pharmacodynamics, demonstrating the capabilities of the miniaturized systems. The integration of individual established microfluidic operations and analytical tools in a single device is a challenge to be overcome to achieve a unique recombinant drug-on-a-chip device. - Highlights: • Principal analytical tools for analysis of recombinant drugs are presented. • A critical comparison among different substrates for fabrication of miniaturized systems is made. • Applications of miniaturized systems to produce recombinant drugs are shown. • Future trends of miniaturized systems capable of integrating analytical and proteomic tools in a single device are envisioned.

A miniature turbocompressor system

Energy Technology Data Exchange (ETDEWEB)

Zwyssig, C.; Kraehenbuehl, D.; Kolar, J. W. [Swiss Federal Institute of Technology, Power Electronic Systems Laboratory, Zuerich (Switzerland); Weser, H. [High Speed Turbomaschinen GmbH, Wolfsburg (Germany)

2008-07-01

The trend in compressors for fuel cells, heat pumps, aerospace and automotive air pressurization, heating, ventilation and air conditioning systems, is towards ultra-compact size and high efficiency. This can be achieved by increasing the rotational speed and employing new electrical drive system technology and materials. This paper presents a miniature, electrically driven turbocompressor system running at a speed of 500,000 rpm. The design includes the thermodynamics, the electric motor, the inverter, the control and the system integration with rotor dynamics and thermal considerations. In the experimental setup, the specified pressure ratio of 1.6 is achieved at a speed of 550,000 rpm, which is slightly higher than the design speed. (author)

Miniature horizontal axis wind turbine system for multipurpose application

International Nuclear Information System (INIS)

Xu, F.J.; Yuan, F.G.; Hu, J.Z.; Qiu, Y.P.

2014-01-01

A MWT (miniature wind turbine) has received great attention recently for powering WISP (Wireless Intelligent Sensor Platform). In this study, two MHAWTs (miniature horizontal axis wind turbines) with and without gear transmission were designed and fabricated. A physics-based model was proposed and the optimal load resistances of the MHAWTs were predicted. The open circuit voltages, output powers and net efficiencies were measured under various ambient winds and load resistances. The experimental results showed the optimal load resistances matched well with the predicted results; the MHAWT without gear obtained higher output power at the wind speed of 2 m/s to 6 m/s, while the geared MHAWT exhibited better performance at the wind speed higher than 6 m/s. In addition, a DCM (discontinuous conduction mode) buck-boost converter was adopted as an interface circuit to maximize the charging power from MHAWTs to rechargeable batteries, exhibiting maximum efficiencies above 85%. The charging power reached about 8 mW and 36 mW at the wind speeds of 4 m/s and 6 m/s respectively, which indicated that the MHAWTs were capable for sufficient energy harvesting for powering low-power electronics continuously. - Highlights: • Performance of the miniature wind turbines with and without gears was compared. • The physics-based model was established and proved successfully. • The interface circuit with efficiency of more than 85% was designed

Whole-genome sequencing reveals a potential causal mutation for dwarfism in the Miniature Shetland pony.

Science.gov (United States)

Metzger, Julia; Gast, Alana Christina; Schrimpf, Rahel; Rau, Janina; Eikelberg, Deborah; Beineke, Andreas; Hellige, Maren; Distl, Ottmar

2017-04-01

The Miniature Shetland pony represents a horse breed with an extremely small body size. Clinical examination of a dwarf Miniature Shetland pony revealed a lowered size at the withers, malformed skull and brachygnathia superior. Computed tomography (CT) showed a shortened maxilla and a cleft of the hard and soft palate which protruded into the nasal passage leading to breathing difficulties. Pathological examination confirmed these findings but did not reveal histopathological signs of premature ossification in limbs or cranial sutures. Whole-genome sequencing of this dwarf Miniature Shetland pony and comparative sequence analysis using 26 reference equids from NCBI Sequence Read Archive revealed three probably damaging missense variants which could be exclusively found in the affected foal. Validation of these three missense mutations in 159 control horses from different horse breeds and five donkeys revealed only the aggrecan (ACAN)-associated g.94370258G>C variant as homozygous wild-type in all control samples. The dwarf Miniature Shetland pony had the homozygous mutant genotype C/C of the ACAN:g.94370258G>C variant and the normal parents were heterozygous G/C. An unaffected full sib and 3/5 unaffected half-sibs were heterozygous G/C for the ACAN:g.94370258G>C variant. In summary, we could demonstrate a dwarf phenotype in a miniature pony breed perfectly associated with a missense mutation within the ACAN gene.

Reduced GABAergic inhibition explains cortical hyperexcitability in the wobbler mouse model of ALS

DEFF Research Database (Denmark)

Nieto-Gonzalez, Jose Luis; Moser, Jakob; Lauritzen, Martin

2011-01-01

mice. Also, miniature inhibitory postsynaptic currents recorded under blockade of action potentials were decreased by 64%. Tonic inhibition mediated by extrasynaptic GABA(A) receptors was reduced by 87%. In agreement, we found a decreased density of parvalbumin- and somatostatin-positive inhibitory...... inhibition, which might explain the cortical hyperexcitability in wobbler mice....

Differential effects of ethanol on regional glutamatergic and GABAergic neurotransmitter pathways in mouse brain.

Science.gov (United States)

Tiwari, Vivek; Veeraiah, Pandichelvam; Subramaniam, Vaidyanathan; Patel, Anant Bahadur

2014-03-01

This study investigates the effects of ethanol on neuronal and astroglial metabolism using (1)H-[(13)C]-NMR spectroscopy in conjunction with infusion of [1,6-(13)C2]/[1-(13)C]glucose or [2-(13)C]acetate, respectively. A three-compartment metabolic model was fitted to the (13)C turnover of GluC3 , GluC4, GABAC 2, GABAC 3, AspC3 , and GlnC4 from [1,6-(13)C2 ]glucose to determine the rates of tricarboxylic acid (TCA) and neurotransmitter cycle associated with glutamatergic and GABAergic neurons. The ratio of neurotransmitter cycle to TCA cycle fluxes for glutamatergic and GABAegic neurons was obtained from the steady-state [2-(13)C]acetate experiment and used as constraints during the metabolic model fitting. (1)H MRS measurement suggests that depletion of ethanol from cerebral cortex follows zero order kinetics with rate 0.18 ± 0.04 μmol/g/min. Acute exposure of ethanol reduces the level of glutamate and aspartate in cortical region. GlnC4 labeling was found to be unchanged from a 15 min infusion of [2-(13)C]acetate suggesting that acute ethanol exposure does not affect astroglial metabolism in naive mice. Rates of TCA and neurotransmitter cycle associated with glutamatergic and GABAergic neurons were found to be significantly reduced in cortical and subcortical regions. Acute exposure of ethanol perturbs the level of neurometabolites and decreases the excitatory and inhibitory activity differentially across the regions of brain. Depletion of ethanol and its effect on brain functions were measured using (1)H and (1)H-[(13)C]-NMR spectroscopy in conjunction with infusion of (13)C-labeled substrates. Ethanol depletion from brain follows zero order kinetics. Ethanol perturbs level of glutamate, and the excitatory and inhibitory activity in mice brain. © 2013 International Society for Neurochemistry.

Two miniature electronic dosemeters Yperwatch - Gamcard

International Nuclear Information System (INIS)

Clavel, B.; Jaillon, J.

1993-01-01

Yperwatch and Gamcard were miniature electronic gamma personal dose and dose rate monitors. The Yperwatch is mounted in a wristwatch and the Gamcard in a case of the size of a standard credit card. The technology provides users with all the performance of a standard professional electronic dosemeter (integrated dose, dose rate, audible alarms, time in use). Yperwatch and Gamcard are based on well-proven electronic dosimetry technology, but with a greater ease of use. (author)

A miniature Hopkinson experiment device based on multistage reluctance coil electromagnetic launch

Science.gov (United States)

Huang, Wenkai; Huan, Shi; Xiao, Ying

2017-09-01

A set of seven-stage reluctance miniaturized Hopkinson bar electromagnetic launcher has been developed in this paper. With the characteristics of high precision, small size, and little noise pollution, the device complies with the requirements of miniaturized Hopkinson bar for high strain rate. The launcher is a seven-stage accelerating device up to 65.5 m/s. A high performance microcontroller is used to control accurately the discharge of capacitor sets, by means of which the outlet velocity of the projectile can be controlled within a certain velocity range.

A miniature Hopkinson experiment device based on multistage reluctance coil electromagnetic launch.

Science.gov (United States)

Huang, Wenkai; Huan, Shi; Xiao, Ying

2017-09-01

A set of seven-stage reluctance miniaturized Hopkinson bar electromagnetic launcher has been developed in this paper. With the characteristics of high precision, small size, and little noise pollution, the device complies with the requirements of miniaturized Hopkinson bar for high strain rate. The launcher is a seven-stage accelerating device up to 65.5 m/s. A high performance microcontroller is used to control accurately the discharge of capacitor sets, by means of which the outlet velocity of the projectile can be controlled within a certain velocity range.

Immobilization of trypsin on miniature incandescent bulbs for infrared-assisted proteolysis

Energy Technology Data Exchange (ETDEWEB)

Ge, Huimin; Bao, Huimin; Zhang, Luyan; Chen, Gang, E-mail: gangchen@fudan.edu.cn

2014-10-03

Highlights: • Trypsin was immobilized on miniature incandescent bulbs via chitosan coating. • The bulbs acted as enzymatic reactors and the generators of infrared radiation. • The bulb bioreactors were successfully employed in infrared-assisted proteolysis. • The proteolysis could accomplish within 5 min with high sequence coverages. - Abstract: A novel efficient proteolysis approach was developed based on trypsin-immobilized miniature incandescent bulbs and infrared (IR) radiation. Trypsin was covalently immobilized in the chitosan coating on the outer surface of miniature incandescent bulbs with the aid of glutaraldehyde. When an illuminated enzyme-immobilized bulb was immersed in protein solution, the emitted IR radiation could trigger and accelerate heterogeneous protein digestion. The feasibility and performance of the novel proteolysis approach were demonstrated by the digestion of hemoglobin (HEM), cytochrome c (Cyt-c), lysozyme (LYS), and ovalbumin (OVA) and the digestion time was significantly reduced to 5 min. The obtained digests were identified by MALDI-TOF-MS with the sequence coverages of 91%, 77%, 80%, and 52% for HEM, Cyt-c, LYS, and OVA (200 ng μL{sup −1} each), respectively. The suitability of the prepared bulb bioreactors to complex proteins was demonstrated by digesting human serum.

Spontaneous intracranial hypotension.

LENUS (Irish Health Repository)

Fullam, L

2012-01-31

INTRODUCTION: Spontaneous\\/primary intracranial hypotension is characterised by orthostatic headache and is associated with characteristic magnetic resonance imaging findings. CASE REPORT: We present a case report of a patient with typical symptoms and classical radiological images. DISCUSSION: Spontaneous intracranial hypotension is an under-recognised cause of headache and can be diagnosed by history of typical orthostatic headache and findings on MRI brain.

[Spontaneous bacterial peritonitis].

Science.gov (United States)

Velkey, Bálint; Vitális, Eszter; Vitális, Zsuzsanna

2017-01-01

Spontaneous bacterial peritonitis occurs most commonly in cirrhotic patients with ascites. Pathogens get into the circulation by intestinal translocation and colonize in peritoneal fluid. Diagnosis of spontaneous bacterial peritonitis is based on elevated polymorphonuclear leukocyte count in the ascites (>0,25 G/L). Ascites culture is often negative but aids to get information about antibiotic sensitivity in positive cases. Treatment in stable patient can be intravenous then orally administrated ciprofloxacin or amoxicillin/clavulanic acid, while in severe cases intravenous III. generation cephalosporin. Nosocomial spontaneous bacterial peritonitis often caused by Gram-positive bacteria and multi-resistant pathogens can also be expected thus carbapenem should be the choice of the empiric treatment. Antibiotic prophylaxis should be considered. Norfloxacin is used most commonly, but changes are expected due to increase in quinolone resistance. As a primary prophylaxis, a short-term antibiotic treatment is recommended after gastrointestinal bleeding for 5 days, while long-term prophylaxis is for patients with low ascites protein, and advanced disease (400 mg/day). Secondary prophylaxis is recommended for all patients recovered from spontaneous bacterial peritonitis. Due to increasing antibiotic use of antibiotics prophylaxis is debated to some degree. Orv. Hetil., 2017, 158(2), 50-57.

Hodoscope module with miniature photomultipliers

International Nuclear Information System (INIS)

Bel'zer, L.I.; Gribushin, A.M.; Zhil'tsov, L.Ya.; Matveeva, E.N.; Philipenko, T.D.; Sinev, N.B.

1987-01-01

The experimental Scintillation Magnetic Spectrometer (SMS) installation, whose main element is an extended hodoscope system, is being built for the accelerator of the High Energy Laboratory of the Joint Institute for Nuclear Research. The authors describe the scintillation hodoscope of the SMS installation and present the applicable amplitude and time characteristics of several types of miniature photomultipliers (FEU-58, FEU-60, FEU-114-1, FEU-147-1, and R-1635 (Hamamatsu, Japan)), which were obtained with a 106 Ru radioactive source and standard plastic scintillators of two types, based on oxazoles in polystyrene and in polymethylmethacrylate

Sensitivity of the prefrontal GABAergic system to chronic stress in male and female mice: Relevance for sex differences in stress-related disorders.

Science.gov (United States)

Shepard, Ryan; Page, Chloe E; Coutellier, Laurence

2016-09-22

Stress-induced modifications of the prefrontal cortex (PFC) are believed to contribute to the onset of mood disorders, such as depression and anxiety, which are more prevalent in women. In depression, the PFC is hypoactive; however the origin of this hypoactivity remains unclear. Possibly, stress could impact the prefrontal GABAergic inhibitory system that, as a result, impairs the functioning of downstream limbic structures controlling emotions. Preclinical evidence indicates that the female PFC is more sensitive to the effects of stress. These findings suggest that exposure to stress could lead to sex-specific alterations in prefrontal GABAergic signaling, which contribute to sex-specific abnormal functioning of limbic regions. These limbic changes could promote the onset of depressive and anxiety behaviors in a sex-specific manner, providing a possible mechanism mediating sex differences in the clinical presentation of stress-related mood disorders. We addressed this hypothesis using a mouse model of stress-induced depressive-like behaviors: the unpredictable chronic mild stress (UCMS) paradigm. We observed changes in prefrontal GABAergic signaling after exposure to UCMS most predominantly in females. Increased parvalbumin (PV) expression and decreased prefrontal neuronal activity were correlated in females with severe emotionality deficit following UCMS, and with altered activity of the amygdala. In males, small changes in emotionality following UCMS were associated with minor changes in prefrontal PV expression, and with hypoactivity of the nucleus accumbens. Our data suggest that prefrontal hypoactivity observed in stress-related mood disorders could result from stress-induced increases in PV expression, particularly in females. This increased vulnerability of the female prefrontal PV system to stress could underlie sex differences in the prevalence and symptomatology of stress-related mood disorders. Copyright © 2016 IBRO. Published by Elsevier Ltd. All

Maintenance energy requirements in miniature colony dogs.

Science.gov (United States)

Serisier, S; Weber, M; Feugier, A; Fardet, M-O; Garnier, F; Biourge, V; German, A J

2013-05-01

There are numerous reports of maintenance energy requirements (MER) in dogs, but little information is available about energy requirements of miniature dog breeds. In this prospective, observational, cohort study, we aimed to determine MER in dogs from a number of miniature breeds and to determine which factors were associated with it. Forty-two dogs participated in the study. MER was calculated by determining daily energy intake (EI) during a period of 196 days (28-359 days) when body weight did not change significantly (e.g. ±2% in 12 weeks). Estimated median MER was 473 kJ/kg(0.75) /day (285-766 kJ/kg(0.75) /day), that is, median 113 kcal/kg(0.75) /day (68-183 kcal/kg(0.75) /day). In the obese dogs that lost weight, median MER after weight loss was completed was 360 kJ/kg(0.75) /day (285-515 kJ/kg(0.75) /day), that is, 86 kcal/kg(0.75) /day, (68-123 kcal/kg(0.75) /day). Simple linear regression analysis suggested that three breeds (e.g. Chihuahua, p = 0.002; Yorkshire terrier, p = 0.039; dachshund, p = 0.035) had an effect on MER. In addition to breed, simple linear regression revealed that neuter status (p = 0.079) and having previously been overweight (p = 0.002) were also of significance. However, with multiple linear regression analysis, only previous overweight status (MER less in dogs previously overweight p = 0.008) and breed (MER greater in Yorkshire terriers [p = 0.029] and less in Chihuahuas [p = 0.089]) remained in the final model. This study is the first to estimate MER in dogs of miniature breeds. Although further information from pet dogs is now needed, the current work will be useful for setting energy and nutrient requirement in such dogs for the future. Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.

Miniature surgical robots in the era of NOTES and LESS: dream or reality?

Science.gov (United States)

Zygomalas, Apollon; Kehagias, Ioannis; Giokas, Konstantinos; Koutsouris, Dimitrios

2015-02-01

Laparoscopy is an established method for the treatment of numerous surgical conditions. Natural orifice transluminal endoscopic surgery (NOTES) is a novel surgical technique that uses the natural orifices of the human body as entrances to the abdominal cavity. An alternative concept of minimally invasive approach to the abdominal cavity is to insert all the laparoscopic instruments through ports using a single small incision on the abdominal wall. A suggested name for this technique is laparoendoscopic single-site surgery (LESS). Considering the technical difficulties in NOTES and LESS and the progress in informatics and robotics, the use of robots seems ideal. The aim of this study is to investigate if there is at present, a realistic possibility of using miniature robots in NOTES or LESS in daily clinical practice. An up-to-date review on in vivo surgical miniature robots is made. A Web-based research of the English literature up to March 2013 using PubMed, Scopus, and Google Scholar as search engines was performed. The development of in vivo miniature robots for use in NOTES or LESS is a reality with great advancements, potential advantages, and possible application in minimally invasive surgery in the future. However, true totally NOTES or LESS procedures on humans using miniature robots either solely or as assistance, remain a dream at present. © The Author(s) 2014.

GABAergic Signaling within a Limbic-Hypothalamic Circuit Integrates Social and Anxiety-Like Behavior with Stress Reactivity.

Science.gov (United States)

Myers, Brent; Carvalho-Netto, Eduardo; Wick-Carlson, Dayna; Wu, Christine; Naser, Sam; Solomon, Matia B; Ulrich-Lai, Yvonne M; Herman, James P

2016-05-01

The posterior hypothalamic nucleus (PH) stimulates autonomic stress responses. However, the role of the PH in behavioral correlates of psychiatric illness, such as social and anxiety-like behavior, is largely unexplored, as is the neurochemistry of PH connectivity with limbic and neuroendocrine systems. Thus, the current study tested the hypothesis that GABAergic signaling within the PH is a critical link between forebrain behavior-regulatory nuclei and the neuroendocrine hypothalamus, integrating social and anxiety-related behaviors with physiological stress reactivity. To address this hypothesis, GABAA receptor pharmacology was used to locally inhibit or disinhibit the PH immediately before behavioral measures of social and anxiety-like behavior in rats. Limbic connectivity of the PH was then established by simultaneous co-injection of anterograde and retrograde tracers. Further, the role of PH GABAergic signaling in neuroendocrine stress responses was tested via inhibition/disinhibition of the PH. These studies determined a prominent role for the PH in the expression of anxiety-related behaviors and social withdrawal. Histological analyses revealed divergent stress-activated limbic input to the PH, emanating predominantly from the prefrontal cortex, lateral septum, and amygdala. PH projections also targeted both parvicellular and magnocellular peptidergic neurons in the paraventricular and supraoptic hypothalamus. Further, GABAA receptor pharmacology determined an excitatory effect of the PH on neuroendocrine responses to stress. These data indicate that the PH represents an important stress-integrative center, regulating behavioral processes and connecting the limbic forebrain with neuroendocrine systems. Moreover, the PH appears to be uniquely situated to have a role in stress-related pathologies associated with limbic-hypothalamic dysfunction.

Canine disorder mirrors human disease: exonic deletion in HES7 causes autosomal recessive spondylocostal dysostosis in miniature Schnauzer dogs.

Directory of Open Access Journals (Sweden)

Cali E Willet

Full Text Available Spondylocostal dysostosis is a congenital disorder of the axial skeleton documented in human families from diverse racial backgrounds. The condition is characterised by truncal shortening, extensive hemivertebrae and rib anomalies including malalignment, fusion and reduction in number. Mutations in the Notch signalling pathway genes DLL3, MESP2, LFNG, HES7 and TBX6 have been associated with this defect. In this study, spondylocostal dysostosis in an outbred family of miniature schnauzer dogs is described. Computed tomography demonstrated that the condition mirrors the skeletal defects observed in human cases, but unlike most human cases, the affected dogs were stillborn or died shortly after birth. Through gene mapping and whole genome sequencing, we identified a single-base deletion in the coding region of HES7. The frameshift mutation causes loss of functional domains essential for the oscillatory transcriptional autorepression of HES7 during somitogenesis. A restriction fragment length polymorphism test was applied within the immediate family and supported a highly penetrant autosomal recessive mode of inheritance. The mutation was not observed in wider testing of 117 randomly sampled adult miniature schnauzer and six adult standard schnauzer dogs; providing a significance of association of Praw = 4.759e-36 (genome-wide significant. Despite this apparently low frequency in the Australian population, the allele may be globally distributed based on its presence in two unrelated sires from geographically distant locations. While isolated hemivertebrae have been observed in a small number of other dog breeds, this is the first clinical and genetic diagnosis of spontaneously occurring spondylocostal dysostosis in a non-human mammal and offers an excellent model in which to study this devastating human disorder. The genetic test can be utilized by dog breeders to select away from the disease and avoid unnecessary neonatal losses.

Canine disorder mirrors human disease: exonic deletion in HES7 causes autosomal recessive spondylocostal dysostosis in miniature Schnauzer dogs.

Science.gov (United States)

Willet, Cali E; Makara, Mariano; Reppas, George; Tsoukalas, George; Malik, Richard; Haase, Bianca; Wade, Claire M

2015-01-01

Spondylocostal dysostosis is a congenital disorder of the axial skeleton documented in human families from diverse racial backgrounds. The condition is characterised by truncal shortening, extensive hemivertebrae and rib anomalies including malalignment, fusion and reduction in number. Mutations in the Notch signalling pathway genes DLL3, MESP2, LFNG, HES7 and TBX6 have been associated with this defect. In this study, spondylocostal dysostosis in an outbred family of miniature schnauzer dogs is described. Computed tomography demonstrated that the condition mirrors the skeletal defects observed in human cases, but unlike most human cases, the affected dogs were stillborn or died shortly after birth. Through gene mapping and whole genome sequencing, we identified a single-base deletion in the coding region of HES7. The frameshift mutation causes loss of functional domains essential for the oscillatory transcriptional autorepression of HES7 during somitogenesis. A restriction fragment length polymorphism test was applied within the immediate family and supported a highly penetrant autosomal recessive mode of inheritance. The mutation was not observed in wider testing of 117 randomly sampled adult miniature schnauzer and six adult standard schnauzer dogs; providing a significance of association of Praw = 4.759e-36 (genome-wide significant). Despite this apparently low frequency in the Australian population, the allele may be globally distributed based on its presence in two unrelated sires from geographically distant locations. While isolated hemivertebrae have been observed in a small number of other dog breeds, this is the first clinical and genetic diagnosis of spontaneously occurring spondylocostal dysostosis in a non-human mammal and offers an excellent model in which to study this devastating human disorder. The genetic test can be utilized by dog breeders to select away from the disease and avoid unnecessary neonatal losses.

Generation of miniaturized planar ecombinant antibody arrays using a microcantilever-based printer

Science.gov (United States)

Petersson, Linn; Berthet Duroure, Nathalie; Auger, Angèle; Dexlin-Mellby, Linda; Borrebaeck, Carl AK; Ait Ikhlef, Ali; Wingren, Christer

2014-07-01

Miniaturized (Ø 10 μm), multiplexed (>5-plex), and high-density (>100 000 spots cm-2) antibody arrays will play a key role in generating protein expression profiles in health and disease. However, producing such antibody arrays is challenging, and it is the type and range of available spotters which set the stage. This pilot study explored the use of a novel microspotting tool, BioplumeTM—consisting of an array of micromachined silicon cantilevers with integrated microfluidic channels—to produce miniaturized, multiplexed, and high-density planar recombinant antibody arrays for protein expression profiling which targets crude, directly labelled serum. The results demonstrated that 16-plex recombinant antibody arrays could be produced—based on miniaturized spot features (78.5 um2, Ø 10 μm) at a 7-125-times increased spot density (250 000 spots cm-2), interfaced with a fluorescent-based read-out. This prototype platform was found to display adequate reproducibility (spot-to-spot) and an assay sensitivity in the pM range. The feasibility of the array platform for serum protein profiling was outlined.

Generation of miniaturized planar ecombinant antibody arrays using a microcantilever-based printer

International Nuclear Information System (INIS)

Petersson, Linn; Dexlin-Mellby, Linda; Borrebaeck, Carl AK; Wingren, Christer; Berthet Duroure, Nathalie; Auger, Angèle; Ait Ikhlef, Ali

2014-01-01

Miniaturized (Ø 10 μm), multiplexed (>5-plex), and high-density (>100 000 spots cm −2 ) antibody arrays will play a key role in generating protein expression profiles in health and disease. However, producing such antibody arrays is challenging, and it is the type and range of available spotters which set the stage. This pilot study explored the use of a novel microspotting tool, Bioplume TM —consisting of an array of micromachined silicon cantilevers with integrated microfluidic channels—to produce miniaturized, multiplexed, and high-density planar recombinant antibody arrays for protein expression profiling which targets crude, directly labelled serum. The results demonstrated that 16-plex recombinant antibody arrays could be produced—based on miniaturized spot features (78.5 um 2 , Ø 10 μm) at a 7–125-times increased spot density (250 000 spots cm −2 ), interfaced with a fluorescent-based read-out. This prototype platform was found to display adequate reproducibility (spot-to-spot) and an assay sensitivity in the pM range. The feasibility of the array platform for serum protein profiling was outlined. (paper)

Genetics Home Reference: primary spontaneous pneumothorax

Science.gov (United States)

... Home Health Conditions Primary spontaneous pneumothorax Primary spontaneous pneumothorax Printable PDF Open All Close All Enable Javascript ... view the expand/collapse boxes. Description Primary spontaneous pneumothorax is an abnormal accumulation of air in the ...

AMINA-chip : a miniaturized measurement system for ambient ammonia

NARCIS (Netherlands)

Timmer, Björn Herman

2004-01-01

The development of a miniaturized and integrated measurement system for gaseous ammonia is described in this thesis. The measuring principle, ¿AMINA¿, is an indirect method for selectively measuring ammonia that makes use of pH-transitions, electrolyte conductivity detection and phaseseparating

Testing the impact of miniaturization on phylogeny: Paleozoic dissorophoid amphibians.

Science.gov (United States)

Fröbisch, Nadia B; Schoch, Rainer R

2009-06-01

Among the diverse clade of Paleozoic dissorophoid amphibians, the small, terrestrial amphibamids and the neotenic branchiosaurids have frequently been suggested as possible antecedents of either all or some of the modern amphibian clades. Classically, amphibamids and branchiosaurids have been considered to represent distinct, but closely related clades within dissorophoids, but despite their importance for the controversial lissamphibian origins, a comprehensive phylogenetic analysis of small dissorophoids has thus far not been attempted. On the basis of an integrated data set, the relationships of amphibamids and branchiosaurids were analyzed using parsimony and Bayesian approaches. Both groups represent miniaturized forms and it was tested whether similar developmental pathways, associated with miniaturization, lead to an artificial close relationship of branchiosaurids and amphibamids. Moreover, the fit of the resulting tree topologies to the distribution of fossil taxa in the stratigraphic rock record was assessed as an additional source of information. The results show that characters associated with a miniaturized morphology are not responsible for the close clustering of branchiosaurids and amphibamids. Instead, all analyses invariably demonstrate a monophyletic clade of branchiosaurids highly nested within derived amphibamids, indicating that branchiosaurids represent a group of secondarily neotenic amphibamid dissorophoids. This understanding of the phylogenetic relationships of small dissorophoid amphibians provides a new framework for the discussion of their evolutionary history and the evolution of characters shared by branchiosaurids and/or amphibamids with modern amphibian taxa.

Analysis of serum and cerebrospinal fluid in clinically normal adult miniature donkeys.

Science.gov (United States)

Mozaffari, A A; Samadieh, H

2013-09-01

To establish reference intervals for serum and cerebrospinal fluid (CSF) parameters in clinically healthy adult miniature donkeys. Experiments were conducted on 10 female and 10 male clinically normal adult miniature donkeys, randomly selected from five herds. Lumbosacral CSF collection was performed with the sedated donkey in the standing position. Cell analysis was performed immediately after the samples were collected. Blood samples were obtained from the jugular vein immediately after CSF sample collection. Sodium, potassium, glucose, urea nitrogen, total protein, calcium, chloride, phosphorous and magnesium concentrations were measured in CSF and serum samples. A paired t-test was used to compare mean values between female and male donkeys. The CSF was uniformly clear, colourless and free from flocculent material, with a specific gravity of 1.002. The range of total nucleated cell counts was 2-4 cells/μL. The differential white cell count comprised only small lymphocytes. No erythrocytes or polymorphonuclear cells were observed on cytological examination. Reference values were obtained for biochemical analysis of serum and CSF. Gender had no effect on any variables measured in serum or CSF (p>0.05). CSF analysis can provide important information in addition to that gained by clinical examination. CSF analysis has not previously been performed in miniature donkeys; this is the first report on the subject. In the present study, reference intervals for total nucleated cell count, total protein, glucose, urea nitrogen, sodium, potassium, chloride, calcium, phosphorous and magnesium concentrations of serum and CSF were determined for male and female miniature donkeys.

Design of a miniaturized integrated spectrometer for spectral tissue sensing

Science.gov (United States)

Belay, Gebirie Yizengaw; Hoving, Willem; Ottevaere, Heidi; van der Put, Arthur; Weltjens, Wim; Thienpont, Hugo

2016-04-01

Minimally-invasive image-guided procedures become increasingly used by physicians to obtain real-time characterization feedback from the tissue at the tip of their interventional device (needle, catheter, endoscopic or laparoscopic probes, etc…) which can significantly improve the outcome of diagnosis and treatment, and ultimately reduce cost of the medical treatment. Spectral tissue sensing using compact photonic probes has the potential to be a valuable tool for screening and diagnostic purposes, e.g. for discriminating between healthy and tumorous tissue. However, this technique requires a low-cost broadband miniature spectrometer so that it is commercially viable for screening at point-of-care locations such as physicians' offices and outpatient centers. Our goal is therefore to develop a miniaturized spectrometer based on diffractive optics that combines the functionalities of a visible/near-infrared (VIS/NIR) and shortwave-infrared (SWIR) spectrometer in one very compact housing. A second goal is that the hardware can be produced in high volume at low cost without expensive time consuming alignment and calibration steps. We have designed a miniaturized spectrometer which operates both in the visible/near-infrared and shortwave-infrared wavelength regions ranging from 400 nm to 1700 nm. The visible/near-infrared part of the spectrometer is designed for wavelengths from 400 nm to 800 nm whereas the shortwave-infrared segment ranges from 850 nm to 1700 nm. The spectrometer has a resolution of 6 nm in the visible/near-infrared wavelength region and 10 nm in the shortwave-infrared. The minimum SNR of the spectrometer for the intended application is about 151 in the VIS/NIR range and 6000 for SWIR. In this paper, the modelling and design, and power budget analysis of the miniaturized spectrometer are presented. Our work opens a door for future affordable micro- spectrometers which can be integrated with smartphones and tablets, and used for point

Miniature photometric stereo system for textile surface structure reconstruction

Science.gov (United States)

Gorpas, Dimitris; Kampouris, Christos; Malassiotis, Sotiris

2013-04-01

In this work a miniature photometric stereo system is presented, targeting the three-dimensional structural reconstruction of various fabric types. This is a supportive module to a robot system, attempting to solve the well known "laundry problem". The miniature device has been designed for mounting onto the robot gripper. It is composed of a low-cost off-the-shelf camera, operating in macro mode, and eight light emitting diodes. The synchronization between image acquisition and lighting direction is controlled by an Arduino Nano board and software triggering. The ambient light has been addressed by a cylindrical enclosure. The direction of illumination is recovered by locating the reflection or the brightest point on a mirror sphere, while a flatfielding process compensates for the non-uniform illumination. For the evaluation of this prototype, the classical photometric stereo methodology has been used. The preliminary results on a large number of textiles are very promising for the successful integration of the miniature module to the robot system. The required interaction with the robot is implemented through the estimation of the Brenner's focus measure. This metric successfully assesses the focus quality with reduced time requirements in comparison to other well accepted focus metrics. Besides the targeting application, the small size of the developed system makes it a very promising candidate for applications with space restrictions, like the quality control in industrial production lines or object recognition based on structural information and in applications where easiness in operation and light-weight are required, like those in the Biomedical field, and especially in dermatology.

The mass miniature chest radiography programme in Cape Town ...

African Journals Online (AJOL)

Background. Tuberculosis (TB) control programmes rely mainly on passive detection of symptomatic individuals. The resurgence of TB has rekindled interest in active case finding. Cape Town (South Africa) had a mass miniature radiography (MMR) screening programme from 1948 to 1994. Objective. To evaluate screening ...

Disposable Miniaturized Screen‐Printed pH and Reference Electrodes for Potentiometric Systems

DEFF Research Database (Denmark)

Musa, Arnaud Emmanuel; del Campo, Francisco Javier; Abramova, Natalia

2011-01-01

This work describes the development of a miniaturized potentiometric system comprising a miniaturized quasi‐reference electrode (QRE) coupled to a solid‐state ion‐selective electrode (ISE) for the monitoring of pH. We describe the optimization of materials and fabrication processes including screen‐printing...... electrode) that can be used continuously for a period of not less than 7 days in aqueous solutions. Curing the Ag/AgCl pastes during 20 minutes at 120 °C after printing allowed the QREs to display excellent potential stability, as demonstrated by an open‐circuit‐potential standard deviation of ±1.2 mV over...

Ziprasidone-induced spontaneous orgasm.

Science.gov (United States)

Boora, K; Chiappone, K; Dubovsky, S; Xu, J

2010-06-01

Neuroleptic treatment in schizophrenic patients has been associated with sexual dysfunction, including impotence and decreased libido. Spontaneous ejaculation without sexual arousal during typical antipsychotic treatment is a rare condition that has been described with zuclopentixol, trifluoperazine, and thiothixene. Here, we are reporting a case of spontaneous orgasm with ziprasidone in a bipolar patient. This patient began to repeatedly experience spontaneous sexual arousal and orgasm, which she had never experienced in the past. Ziprasidone might be causing an increase in sexual orgasm by 5-HT2 receptor antagonism, which preclinical evidence suggests that it facilitates dopamine release in the cortex.

Adeno-associated virus transformation into the normal miniature pig and the normal guinea pigs cochlea via scala tympani.

Science.gov (United States)

Shi, Xunbei; Wu, Nan; Zhang, Yue; Guo, Weiwei; Lin, Chang; Yang, Shiming

2017-09-01

To investigate the expression of the miniature pig cochlea after AAV1 transfect into the cochlea via round window membrane (RWM). Twenty miniature pigs are equally divided into four experimental groups. Twelve miniature pigs are equally divided into four control groups. Each pig was transfected with the AAV1 in the experimental group via RWM and each pig was transduced with the artificial perilymph in the control group. The expression of green fluorescent protein (GFP) was observed at 2 weeks, 3 weeks and 4 weeks, respectively. Likewise, AAV1 was delivered into the guinea pigs cochleas using the same method, and the results were compared with that of the miniature pigs. The expression was mainly in the inner hair cells of the miniature pig. The expression of GFP began to appear at 2 weeks, reached the peak at 3 weeks. It also expressed in Hensen's cells, inner pillar cells, outer pillar cells, spiral limbus, and spiral ligament. In the meanwhile, AAV1 was delivered into guinea pig cochlea via the same method, and AAV1 was also expressed in the inner hair cells. But the expression peaked at 2 weeks, and the efficiency of the inner hair cell transfection was higher than that of the pig. AAV1 can be transformed into miniature pig cochlea via scala tympani by the RWM method efficiently.

Development of a miniature autofluorescence device for the early diagnosis of squamous cell carcinoma

Science.gov (United States)

Patil, Ajeetkumar; Rao K., Swati; V. K., Unnikrishnan; Pai, Keerthilatha M.; Kartha, V. B.; Chidangil, Santhosh

2017-07-01

Autofluorescence spectroscopy offer noninvasive and promising tools for the detection of alternations biochemical compositions of tissues and cells, in presence of disease. They have the added advantage of being highly objective due to the fact that diagnostic evaluation is by statistical methods, eliminating errors from lack of experience, fatigue factor, and subjectivity of visual perceptions. The present research work involves in designing and assembling of a low cost, miniature oral cancer screening device with for routine clinical applications. A miniature system was designed and assembled with much smaller and cost-effective components like compact light source and miniature spectrometer, in a hand-held unit configuration. The performance of the system was evaluated using animal -mouse- SCC model. The current system can be used in handheld operation, which makes it very useful for many applications like, screening of squamous cell carcinoma susceptible population.

Miniature sources of irradiation for intracavitary thermo radiotherapy

Science.gov (United States)

Taubin, M.; Chesnokov, D.; Simonov, A.

2018-02-01

This report presents the development of a miniature ionizing and thermal radiation source for oncological diseases treatment namely the inward parts of the body. This source can be placed next to the tumor inside of the body. This report is only about methods and devices for the intracavitary therapy. Irradiation by external sources wasn’t considered in our investigation.

Miniaturized Spacecraft Platform for Command, Data Handling and Electronics, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Microelectronics Research Development Corporation (Micro RDC) proposes to develop a platform of low mass/volume/power, reliable miniaturized electronic modules that...

Long Life Miniature Hall Thruster Enabling Low Cost Human Precursor Missions

Data.gov (United States)

National Aeronautics and Space Administration — Key and Central Objectives: This investigation aims to demonstrate that the application of magnetic shielding technology on miniature Hall thrusters will...

Miniature Heat Pipes

Science.gov (United States)

1997-01-01

Small Business Innovation Research contracts from Goddard Space Flight Center to Thermacore Inc. have fostered the company work on devices tagged "heat pipes" for space application. To control the extreme temperature ranges in space, heat pipes are important to spacecraft. The problem was to maintain an 8-watt central processing unit (CPU) at less than 90 C in a notebook computer using no power, with very little space available and without using forced convection. Thermacore's answer was in the design of a powder metal wick that transfers CPU heat from a tightly confined spot to an area near available air flow. The heat pipe technology permits a notebook computer to be operated in any position without loss of performance. Miniature heat pipe technology has successfully been applied, such as in Pentium Processor notebook computers. The company expects its heat pipes to accommodate desktop computers as well. Cellular phones, camcorders, and other hand-held electronics are forsible applications for heat pipes.

Miniature ionization chamber

International Nuclear Information System (INIS)

Alexeev, V.I.; Emelyanov, I.Y.; Ivanov, V.M.; Konstantinov, L.V.; Lysikov, B.V.; Postnikov, V.V.; Rybakov, J.V.

1976-01-01

A miniature ionization chamber having a gas-filled housing which accommodates a guard electrode made in the form of a hollow perforated cylinder is described. The cylinder is electrically associated with the intermediate coaxial conductor of a triaxial cable used as the lead-in of the ionization chamber. The gas-filled housing of the ionization chamber also accommodates a collecting electrode shaped as a rod electrically connected to the center conductor of the cable and to tubular members. The rod is disposed internally of the guard electrode and is electrically connected, by means of jumpers passing through the holes in the guard electrode, to the tubular members. The tubular members embrace the guard electrode and are spaced a certain distance apart along its entire length. Arranged intermediate of these tubular members are spacers secured to the guard electrode and fixing the collecting electrode throughout its length with respect to the housing of the ionization chamber

Ultrathin Graphene-Protein Supercapacitors for Miniaturized Bioelectronics.

Science.gov (United States)

Mosa, Islam M; Pattammattel, Ajith; Kadimisetty, Karteek; Pande, Paritosh; El-Kady, Maher F; Bishop, Gregory W; Novak, Marc; Kaner, Richard B; Basu, Ashis K; Kumar, Challa V; Rusling, James F

2017-09-06

Nearly all implantable bioelectronics are powered by bulky batteries which limit device miniaturization and lifespan. Moreover, batteries contain toxic materials and electrolytes that can be dangerous if leakage occurs. Herein, an approach to fabricate implantable protein-based bioelectrochemical capacitors (bECs) employing new nanocomposite heterostructures in which 2D reduced graphene oxide sheets are interlayered with chemically modified mammalian proteins, while utilizing biological fluids as electrolytes is described. This protein-modified reduced graphene oxide nanocomposite material shows no toxicity to mouse embryo fibroblasts and COS-7 cell cultures at a high concentration of 1600 μg mL -1 which is 160 times higher than those used in bECs, unlike the unmodified graphene oxide which caused toxic cell damage even at low doses of 10 μg mL -1 . The bEC devices are 1 μm thick, fully flexible, and have high energy density comparable to that of lithium thin film batteries. COS-7 cell culture is not affected by long-term exposure to encapsulated bECs over 4 d of continuous charge/discharge cycles. These bECs are unique, protein-based devices, use serum as electrolyte, and have the potential to power a new generation of long-life, miniaturized implantable devices.

Miniature Non-Intrusive Multi-Parameter Oronasal Respiratory Health Monitor, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Redondo Optics Inc. (ROI), proposes to develop, demonstrate, and deliver to NASA an intrinsically safe, miniature, low power, autonomous, and self-calibrated,...

Challenges in miniaturized automotive long-range lidar system design

Science.gov (United States)

Fersch, Thomas; Weigel, Robert; Koelpin, Alexander

2017-05-01

This paper discusses the current technical limitations posed on endeavors to miniaturize lidar systems for use in automotive applications and how to possibly extend those limits. The focus is set on long-range scanning direct time of flight LiDAR systems using APD photodetectors. Miniaturization evokes severe problems in ensuring absolute laser safety while maintaining the systems' performance in terms of maximum range, signal-to-noise ratio, detection probability, pixel density, or frame rate. Based on hypothetical but realistic specifications for an exemplary system the complete lidar signal path is calculated. The maximum range of the system is used as a general performance indicator. It is determined with the minimum signal-to-noise ratio required to detect an object. Various system parameters are varied to find their impact on the system's range. The reduction of the laser's pulse width and the right choice for the transimpedance amplifier's amplification have shown to be practicable measures to double the system's range.

Assessing the use of Low Voltage UV-light Emitting Miniature LEDs for Marine Biofouling Control

Science.gov (United States)

2016-07-01

of that required to drive traditional UV mercury lamps . Secondly, given their small size and relatively low cost, UV LEDs provide ease of maintenance...UNCLASSIFIED UNCLASSIFIED Assessing the use of Low Voltage UV -light Emitting Miniature LEDs for Marine Biofouling Control Richard...settling organisms. The introduction of miniature UV light emitting diodes ( LEDs ) as a light source enables them to be embedded into thin, flexible

Miniaturized Ultrasound Imaging Probes Enabled by CMUT Arrays with Integrated Frontend Electronic Circuits

Science.gov (United States)

Khuri-Yakub, B. (Pierre) T.; Oralkan, Ömer; Nikoozadeh, Amin; Wygant, Ira O.; Zhuang, Steve; Gencel, Mustafa; Choe, Jung Woo; Stephens, Douglas N.; de la Rama, Alan; Chen, Peter; Lin, Feng; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai; Shivkumar, Kalyanam; Mahajan, Aman; Seo, Chi Hyung; O’Donnell, Matthew; Truong, Uyen; Sahn, David J.

2010-01-01

Capacitive micromachined ultrasonic transducer (CMUT) arrays are conveniently integrated with frontend integrated circuits either monolithically or in a hybrid multichip form. This integration helps with reducing the number of active data processing channels for 2D arrays. This approach also preserves the signal integrity for arrays with small elements. Therefore CMUT arrays integrated with electronic circuits are most suitable to implement miniaturized probes required for many intravascular, intracardiac, and endoscopic applications. This paper presents examples of miniaturized CMUT probes utilizing 1D, 2D, and ring arrays with integrated electronics. PMID:21097106

Miniature fuel cells relieve gas pressure in sealed batteries

Science.gov (United States)

Frank, H. A.

1971-01-01

Miniature fuel cells within sealed silver zinc batteries consume evolved hydrogen and oxygen rapidly, preventing pressure rupturing. They do not significantly increase battery weight and they operate in all battery life phases. Complete gas pressure control requires two fuel cells during all phases of operation of silver zinc batteries.

Small scale monitoring of a bioremediation barrier using miniature electrical resistivity tomography

Science.gov (United States)

Sentenac, Philippe; Hogson, Tom; Keenan, Helen; Kulessa, Bernd

2015-04-01

The aim of this study was to assess, in the laboratory, the efficiency of a barrier of oxygen release compound (ORC) to block and divert a diesel plume migration in a scaled aquifer model using miniature electrical resistivity tomography (ERT) as the monitoring system. Two plumes of contaminant (diesel) were injected in a soil model made of local sand and clay. The diesel plumes migration was imaged and monitored using a miniature resistivity array system that has proved to be accurate in soil resistivity variations in small-scaled models of soil. ERT results reflected the lateral spreading and diversion of the diesel plumes in the unsaturated zone. One of the contaminant plumes was partially blocked by the ORC barrier and a diversion and reorganisation of the diesel in the soil matrix was observed. The technique of time-lapse ERT imaging showed that a dense non-aqueous phase liquid (DNAPL) contaminant like diesel can be monitored through a bioremediation barrier and the technique is well suited to monitor the efficiency of the barrier. Therefore, miniature ERT as a small-scale modelling tool could complement conventional techniques, which require more expensive and intrusive site investigation prior to remediation.

The concept and application of miniaturization boiling in cooling system

International Nuclear Information System (INIS)

Suhaimi Illias; Muhammad Asri Idris

2009-01-01

The purpose of this research is to study and examine the phenomena of miniaturization-boiling, which intensely scatters with a large number of minute liquid particles from a water droplet surface to the atmosphere, when the droplet collided with a heating surface. As the material of the heating surface, the following were used: stainless steel (SUS 303 A Cr=17%,Ni=8%), sapphire (Al 3 O 2 ), brass, copper and carbon plane. The material was heated in order to study the miniaturization-boiling and droplet bounding phenomena at a very high temperature (160 degree C- 420 degree C). The phenomenon was photographed by a high-speed camera (10,000 fps) from the horizontal direction. The nuclear fusion reactor needs a very severe cooling, heat removal cooling method by special boiling is lead to this research. (Author)

A Miniature Probe for Ultrasonic Penetration of a Single Cell

Directory of Open Access Journals (Sweden)

Mingfei Xiao

2009-05-01

Full Text Available Although ultrasound cavitation must be avoided for safe diagnostic applications, the ability of ultrasound to disrupt cell membranes has taken on increasing significance as a method to facilitate drug and gene delivery. A new ultrasonic resonance driving method is introduced to penetrate rigid wall plant cells or oocytes with springy cell membranes. When a reasonable design is created, ultrasound can gather energy and increase the amplitude factor. Ultrasonic penetration enables exogenous materials to enter cells without damaging them by utilizing instant acceleration. This paper seeks to develop a miniature ultrasonic probe experiment system for cell penetration. A miniature ultrasonic probe is designed and optimized using the Precise Four Terminal Network Method and Finite Element Method (FEM and an ultrasonic generator to drive the probe is designed. The system was able to successfully puncture a single fish cell.

GABAergic mechanisms are involved in the antihyperalgesic effects of carbamazepine and oxcarbazepine in a rat model of inflammatory hyperalgesia.

Science.gov (United States)

Stepanović-Petrović, Radica M; Tomić, Maja A; Vucković, Sonja M; Kocev, Nikola; Ugresić, Nenad D; Prostran, Milica S; Bosković, Bogdan

2008-01-01

The purpose of this study was to investigate the involvement of GABAergic mechanisms in the antihyperalgesic effect of carbamazepine and oxcarbazepine by examining the effect of bicuculline (GABA(A) receptor antagonist) on these effects of antiepileptic drugs. Rats were intraplantarly (i.pl.) injected with the proinflammatory compound concanavalin A (Con A). A paw-pressure test was used to determine: (1) the development of hyperalgesia induced by Con A; (2) the effects of carbamazepine/oxcarbazepine on Con A-induced hyperalgesia, and (3) the effects of bicuculline on the carbamazepine/oxcarbazepine antihyperalgesia. Intraperitoneally injected bicuculline (0.5-1 mg/kg, i.p.) exhibited significant suppression of the systemic antihyperalgesic effects of carbamazepine (27 mg/kg, i.p.) and oxcarbazepine (80 mg/kg, i.p.). When applied intraplantarly, bicuculline (0.14 mg/paw, i.pl.) did not produce any change in the peripheral antihyperalgesic effects of carbamazepine (0.14 mg/paw, i.pl.) and oxcarbazepine (0.5 mg/paw, i.pl.). Bicuculline alone did not produce an intrinsic effect in the paw-pressure test. These results indicate that the antihyperalgesic effects of carbamazepine and oxcarbazepine against inflammatory hyperalgesia involve in part the GABAergic inhibitory modulation of pain transmission at central, but not at peripheral sites, which is mediated via GABA(A) receptor activation. Copyright 2008 S. Karger AG, Basel.

Development of a micromirror-scanned multimodal CARS miniaturized microscope for the in vivo study of spinal cord disorders

Science.gov (United States)

Murugkar, Sangeeta; Smith, Brett; Naji, Majid; Brideau, Craig; Stys, Peter; Anis, Hanan

2011-03-01

We discuss the design and implementation of a novel multimodal coherent anti-Stokes Raman scattering (CARS) miniaturized microscope for imaging of injured and recovering spinal cords in a single living animal. We demonstrate for the first time, the use of a biaxial microelectromechanical system (MEMS) mirror for scanning and diffraction limited multiple lens miniaturized objective for exciting a CARS signal. The miniaturized microscope design includes light delivery using a large mode area photonic crystal fiber (PCF), and multimode fiber for collection of the nonlinear optical signal. The basic design concept, major engineering challenges, solutions, and preliminary results are presented. We demonstrate CARS and two photon excitation fluorescence microscopy in a benchtop setup with the miniaturized optics and MEMS scanning. The light source is based on a single femtosecond laser (pump beam) and a supercontinuum generated in a nonlinear PCF (Stokes beam). This is coupled using free space optics onto the surface of a resonantly driven two dimensional scanning MEMS mirror that scans the excitation light in a Lissajous pattern. The novel design of the miniaturized microscope is expected to provide significant new information on the pathogenesis of demyelinating diseases such as Multiple Sclerosis and Spinal Cord Injury.

Disposable Fluidic Actuators for Miniature In-Vivo Surgical Robotics.

Science.gov (United States)

Pourghodrat, Abolfazl; Nelson, Carl A

2017-03-01

Fusion of robotics and minimally invasive surgery (MIS) has created new opportunities to develop diagnostic and therapeutic tools. Surgical robotics is advancing from externally actuated systems to miniature in-vivo robotics. However, with miniaturization of electric-motor-driven surgical robots, there comes a trade-off between the size of the robot and its capability. Slow actuation, low load capacity, sterilization difficulties, leaking electricity and transferring produced heat to tissues, and high cost are among the key limitations of the use of electric motors in in-vivo applications. Fluid power in the form of hydraulics or pneumatics has a long history in driving many industrial devices and could be exploited to circumvent these limitations. High power density and good compatibility with the in-vivo environment are the key advantages of fluid power over electric motors when it comes to in-vivo applications. However, fabrication of hydraulic/pneumatic actuators within the desired size and pressure range required for in-vivo surgical robotic applications poses new challenges. Sealing these types of miniature actuators at operating pressures requires obtaining very fine surface finishes which is difficult and costly. The research described here presents design, fabrication, and testing of a hydraulic/pneumatic double-acting cylinder, a limited-motion vane motor, and a balloon-actuated laparoscopic grasper. These actuators are small, seal-less, easy to fabricate, disposable, and inexpensive, thus ideal for single-use in-vivo applications. To demonstrate the ability of these actuators to drive robotic joints, they were modified and integrated in a robotic arm. The design and testing of this surgical robotic arm are presented to validate the concept of fluid-power actuators for in-vivo applications.

Circuits and Systems for Low-Power Miniaturized Wireless Sensors

Science.gov (United States)

Nagaraju, Manohar

The field of electronic sensors has witnessed a tremendous growth over the last decade particularly with the proliferation of mobile devices. New applications in Internet of Things (IoT), wearable technology, are further expected to fuel the demand for sensors from current numbers in the range of billions to trillions in the next decade. The main challenges for a trillion sensors are continued miniaturization, low-cost and large-scale manufacturing process, and low power consumption. Traditional integration and circuit design techniques in sensor systems are not suitable for applications in smart dust, IoT etc. The first part of this thesis demonstrates an example sensor system for biosignal recording and illustrates the tradeoffs in the design of low-power miniaturized sensors. The different components of the sensor system are integrated at the board level. The second part of the thesis demonstrates fully integrated sensors that enable extreme miniaturization of a sensing system with the sensor element, processing circuitry, a frequency reference for communication and the communication circuitry in a single hermetically sealed die. Design techniques to reduce the power consumption of the sensor interface circuitry at the architecture and circuit level are demonstrated. The principles are used to design sensors for two of the most common physical variables, mass and pressure. A low-power wireless mass and pressure sensor suitable for a wide variety of biological/chemical sensing applications and Tire Pressure Monitoring Systems (TPMS) respectively are demonstrated. Further, the idea of using high-Q resonators for a Voltage Controlled Oscillator (VCO) is proposed and a low-noise, wide bandwidth FBAR-based VCO is presented.

A Miniaturize Bandpass Filter with Harmonic Suppression Using Meandered Quarter-Wavelength Resonators

Directory of Open Access Journals (Sweden)

Yun-Long Lu

2014-01-01

Full Text Available A miniaturized bandpass filter with harmonics suppression is presented. The proposed filter consists of two quarter-wavelength microstrip resonators, which are meandered for circuit size reduction. An interdigital capacitor, loading at zero-voltage point, is employed to provide the desired coupling between the resonators at operating frequency, whereas the coupling coefficient at the third harmonic is realized to be zero. Besides, the second and fourth harmonics are suppressed since λ/4 resonators are adopted. Benefiting from these properties, a miniaturized bandpass filter with the second, third, and fourth harmonics suppression was designed and implemented. The final measured and simulated results show good consistence with the theoretical counterparts.

Miniature probe with semiconductor photodiode for measuring dose rates in radiotherapy

International Nuclear Information System (INIS)

Burian, A.

1991-01-01

The probe is designed for gaining information on the magnitude and spatial distribution of the dose which will be absorbed by the patient's body during radiotherapy. The probe satisfies requirements of high-level miniaturization and requirements on the shape and tissue-equivalence of the casing, as well as on efficient electromagnetic shielding. It is fitted with a miniature photodiode. Conductive carbon cement was used for attaching contacts to the photodiode. Efficient electromagnetic shielding was achieved by means of a carbon-based conductive layer. The photodiode casing was made from a mixture of organic materials whose biogenic elements approximate the standard soft human tissue. The geometry of the casing is adapted to the particular field of application of the probe. (Z.S). 2 figs

Miniature GC: Minicell ion mobility spectrometer (IMS) for astrobiology planetary missions

Science.gov (United States)

Kojiro, Daniel R.; Holland, Paul M.; Stimac, Robert M.; Kaye, William J.; Takeuchi, Norishige

2006-01-01

Astrobiology flight experiments require highly sensitive instrumentation for in situ analysis of volatile chemical species and minerals present in the atmospheres and surfaces of planets, moons, and asteroids. The complex mixtures encountered place a heavy burden on the analytical instrumentation to detect and identify all species present. The use of land rovers and balloon aero-rovers place additional emphasis on miniaturization of the analytical instrumentation. In addition, smaller instruments, using tiny amounts of consumables, allow the use of more instrumentation and/or longer mission life for stationary landers/laboratories. We describe here the development of a miniature GC - Minicell Ion Mobility Spectrometer (IMS) under development through NASA's Astrobiology Science and Technology Instrument Development (ASTID) Program and NASA's Small Business Innovative Research (SBIR) Program.

Spontaneous rib fractures.

Science.gov (United States)

Katrancioglu, Ozgur; Akkas, Yucel; Arslan, Sulhattin; Sahin, Ekber

2015-07-01

Other than trauma, rib fracture can occur spontaneously due to a severe cough or sneeze. In this study, patients with spontaneous rib fractures were analyzed according to age, sex, underlying pathology, treatment, and complications. Twelve patients who presented between February 2009 and February 2011 with spontaneous rib fracture were reviewed retrospectively. The patients' data were evaluated according to anamnesis, physical examination, and chest radiographs. The ages of the patients ranged from 34 to 77 years (mean 55.91 ± 12.20 years), and 7 (58.4%) were male. All patients had severe cough and chest pain. The fractures were most frequently between 4th and 9th ribs; multiple rib fractures were detected in 5 (41.7%) patients. Eight (66.7%) patients had chronic obstructive pulmonary disease, 2 (16.7%) had bronchial asthma, and 2 (16.7%) had osteoporosis. Bone densitometry revealed a high risk of bone fracture in all patients. Patients with chronic obstructive pulmonary disease or bronchial asthma had been treated with high-dose steroids for over a year. Spontaneous rib fracture due to severe cough may occur in patients with osteoporosis, chronic obstructive pulmonary disease, or bronchial asthma, receiving long-term steroid therapy. If these patients have severe chest pain, chest radiography should be performed to check for bone lesions. © The Author(s) 2015.

GABAergic circuits control input-spike coupling in the piriform cortex.

Science.gov (United States)

Luna, Victor M; Schoppa, Nathan E

2008-08-27

Odor coding in mammals is widely believed to involve synchronized gamma frequency (30-70 Hz) oscillations in the first processing structure, the olfactory bulb. How such inputs are read in downstream cortical structures however is not known. Here we used patch-clamp recordings in rat piriform cortex slices to examine cellular mechanisms that shape how the cortex integrates inputs from bulb mitral cells. Electrical stimulation of mitral cell axons in the lateral olfactory tract (LOT) resulted in excitation of pyramidal cells (PCs), which was followed approximately 10 ms later by inhibition that was highly reproducible between trials in its onset time. This inhibition was somatic in origin and appeared to be driven through a feedforward mechanism, wherein GABAergic interneurons were directly excited by mitral cell axons. The precise inhibition affected action potential firing in PCs in two distinct ways. First, by abruptly terminating PC excitation, it limited the PC response to each EPSP to exactly one, precisely timed action potential. In addition, inhibition limited the summation of EPSPs across time, such that PCs fired action potentials in strong preference for synchronized inputs arriving in a time window of inputs arriving as a synchronized gamma frequency pattern.

Some characteristics of a miniature neutron spectrometer

International Nuclear Information System (INIS)

Sekimoto, H.; Oishi, K.; Hojo, K.; Hojo, T.

1984-01-01

Some characteristics of an NE213 miniature spherical spectrometer for in-assembly fast-neutron spectrometry were measured. As the bubbling time changed, the pulse-height did not change appreciably, but the n-γ discrimination characteristics changed considerably. As the count rate changed, the pulse-height did not change appreciably, and the change of the n-γ discrimination characteristics was acceptable. The neutron response function was measured to be almost isotropic except for the backward direction. (orig.)

Vestibular-evoked myogenic potentials in miniature pigs

Directory of Open Access Journals (Sweden)

Xi Shi

2016-06-01

Conclusion: The latencies and thresholds of VEMPs recorded from the neck extensor muscle and the masseter muscle appear to be comparable in normal adult Bama miniature pigs, although the amplitude recorded from the neck extensor muscle seems to be higher than that from the masseter muscle. However, because of their usually relatively superficial and easily accessible location, as well as their large volume and strong contractions, masseter muscles may be better target muscles for recording myogenic potentials.

Organization of the torus longitudinalis in the rainbow trout (Oncorhynchus mykiss): an immunohistochemical study of the GABAergic system and a DiI tract-tracing study.

Science.gov (United States)

Folgueira, Mónica; Sueiro, Catalina; Rodríguez-Moldes, Isabel; Yáñez, Julián; Anadón, Ramón

2007-07-10

The torus longitudinalis (TL) is a tectum-associated structure of actinopterygian fishes. The organization of the TL of rainbow trout was studied with Nissl staining, Golgi methods, immunocytochemistry with antibodies to gamma-aminobutyric acid (GABA), glutamic acid decarboxylase (GAD), and the GABA(A) receptor subunits delta and beta2/beta 3, and with tract tracing methods. Two types of neuron were characterized: medium-sized GABAergic neurons and small GABA-negative granule cells. GABA(A) receptor subunit delta-like immunoreactivity delineated two different TL regions, ventrolateral and central. Small GABAergic cells were also observed in marginal and periventricular strata of the optic tectum. These results indicate the presence of local GABAergic inhibitory circuits in the TL system. For tract-tracing, a lipophilic dye (DiI) was applied to the TL and to presumed toropetal nuclei or toral targets. Toropetal neurons were observed in the optic tectum, in pretectal (central, intermediate, and paracommissural) nuclei, in the subvalvular nucleus, and associated with the pretectocerebellar tract. Torofugal fibers were numerous in the stratum marginale of the optic tectum. Toropetal pretectal nuclei also project to the cerebellum, and a few TL cells project to the cerebellar corpus. The pyramidal cells of the trout tectum were also studied by Golgi methods and local DiI labeling. The connections of trout TL revealed here were more similar to those recently reported in carp and holocentrids (Ito et al. [2003] J. Comp. Neurol. 457:202-211; Xue et al. [2003] J. Comp. Neurol. 462:194-212), than to those reported in earlier studies. However, important differences in organization of toropetal nuclei were noted between salmonids and these other teleosts. (c) 2007 Wiley-Liss, Inc.

Evaluation of computed tomographic and radiographic myelography in normal miniature pigs

International Nuclear Information System (INIS)

Choi, M.H.; Lee, H.Y.; Kim, M.E.; Kim, J.Y.; Lee, N.S.; Chang, J.H.; Jung, J.H.; Choi, M.C.

2010-01-01

Evaluation of the myelography was studied in miniature pigs. Radiographs and computed tomographic (CT) images of the whole spine were obtained at clinically healthy twelve miniature pigs of 4 (8.7-10 kg) and 12 (26-31 kg) months. The assessments of the spinal cord were made in accordance with the Pavlov's method and compared area ratio [at spinal cord (SC), vertebral canal (VC) and vertebral body (VB)]. The Pavlov's ratio in the cervical spine was significant larger than that of thoracolumbar in radiographic myelography. On CT myelography, the area of the spinal cord had a significant difference between the cervical and thoracolumbar spine. Among the cervical spine, the ratios of spinal cord and vertebral body (SC : VB), vertebral canal and vertebral body (VC : VB) were minimum at the level of 4th cervical spine in both ages, while maximum at the level of 6th cervical spine in both months. In case of lumbar spine, the ratios of spinal cord and vertebral body (SC : VB) were the largest at the level of 4th lumbar spine in 4 months and at the level of 3rd lumbar spine in 12 months. In addition, the ratio of spinal cord and vertebral body (SC : VB) of the cervical spinal cord was significant lower at 4 months but the lumbar spinal cord showed lower pattern at 12 months old miniature pigs

A novel 2nd-order bandpass MFSS filter with miniaturized structure

Directory of Open Access Journals (Sweden)

C. Y. Fang

2015-08-01

Full Text Available In order to effectively obtain a miniaturized structure and good filtering properties, we propose a novel 2nd-order bandpass metamaterial frequency selective surface (MFSS filter which contains two capacitive layers and one inductive layer, where there are multi-loop metallic patches as shunt capacitor C and planar wire grids as series inductor L respectively. Unlike the traditional operation way—the tuned elements used in resonant surface approximately equal to one wavelength in circumference and the structure thickness with a spacing of a quarter wavelength apart, by changing the value of L and C and matching multilayer dielectric to adjust the LC coupling resonance and the resonance impedance respectively, the proposed MFSS filter can achieves a miniatured structure with ideal bandpass properties. Measurement results of the fabricated prototype of the bandpass filter (BPF indicate that the dimension of the tuned element on resonant surface is approximately 0.025 wavelength, i.e., 0.025λ. At the same time, the filter has the stable center frequency of f0 = 1.53GHz and the transmittance of T ⩾ 96.3% and high Q-value for the TE/TM wave polarization at various incidence angles. The novel 2nd-order bandpass MFSS filter with miniaturized structure not only can decrease structure dimension, but also has a wide range of applications to microwave and infrared band.

Comparison of Miniaturized and Conventional Asymmetrical Flow Field-Flow Fractionation (AF4 Channels for Nanoparticle Separations

Directory of Open Access Journals (Sweden)

Zengchao You

2017-03-01

Full Text Available The performance of a miniaturized channel for the separation of polymer and metal nanoparticles (NP using Asymmetrical Flow Field-Flow Fractionation (AF4 was investigated and compared with a conventional AF4 system. To develop standard separation methods, experimental parameters like cross flow, gradient profile and injection time were varied and optimized. Corresponding chromatographic parameters were calculated and compared. Our results indicate that the chromatographic resolution in the miniaturized channel is lower, whereas significantly shorter analyses time and less solvent consumption were obtained. Moreover, the limit of detection (LOD and limit of quantification (LOQ obtained from hyphenation with a UV-detector are obviously lower than in a conventional channel, which makes the miniaturized channel interesting for trace analysis.

Anatomy of adult Megaphragma (Hymenoptera: Trichogrammatidae, one of the smallest insects, and new insight into insect miniaturization.

Directory of Open Access Journals (Sweden)

Alexey A Polilov

Full Text Available The body size, especially in cases of extreme reduction, is an important characteristic that strongly determines the morphology, physiology, and biology of animals. Miniaturization is a widespread trend in animal evolution and one of the principal directions of evolution in insects. Miniaturization-related features of insect morphology have been subject to intensive studies during the last few years, but the structure of the smallest insects remains insufficiently known. It is especially important to study hymenopterans of the genus Megaphragma, which include the smallest flying insects and a species in which an almost anucleate nervous system was recently discovered. This article is the first detailed study of the external and internal morphology of adults of Megaphragma mymaripenne and M. amalphitanum using histological methods, 3D computer modeling and other techniques. It is shown that in spite of the extremely small size the organization of Megaphragma retains a considerkable level of structural complexity. On the other hand, miniaturization leads to re-organizations of several organ systems. Unique structural features related to miniaturization have been found in both species: lysis of cell bodies and nuclei of neurons at late stages of pupal development, absence of the heart, and considerable reductions in the set of muscles. Comparative analysis of structure in the smallest insects representing different taxa has revealed common features of the evolutionary process of miniaturization in insects.

A Fluorescence Based Miniaturized Detection Module for Toxin Producing Algae

Science.gov (United States)

Zieger, S. E.; Mistlberger, G.; Troi, L.; Lang, A.; Holly, C.; Klimant, I.

2016-12-01

Algal blooms are sensitive to external environmental conditions and may pose a serious threat to marine and human life having an adverse effect on the ecosystem. Harmful algal blooms can produce different toxins, which can lead to massive fish kills or to human disorders. Facing these problems, miniaturized and low-cost instrumentation for an early detection and identification of harmful algae classes has become more important over the last years. 1,2Based on the characteristic pigment pattern of different algae classes, we developed a miniaturized detection module, which is able to detect and identify algae classes after analyzing their spectral behavior. Our device combines features of a flow-cytometer and fluorimeter and is build up as a miniaturized and low-cost device of modular design. Similar to a fluorimeter, it excites cells in the capillary with up to 8 different excitation wavelengths recording the emitted fluorescence at 4 different emission channels. Furthermore, the device operates in a flow-through mode similar to a flow-cytometer, however, using only low-cost elements such as LEDs and photodiodes. Due to its miniaturized design, the sensitivity and selectivity increase, whereas background effects are reduced. With a sampling frequency of 140 Hz, we try to detect and count particular cell events even at a concentration of 2 cells / 7.3 µL illuminated volume. Using a self-learning multivariate algorithm, the data are evaluated autonomously on the device enabling an in-situ analysis. The flexibility in choosing excitation and emission wavelengths as well as the high sampling rate enables laboratory applications such as measuring induction kinetics. However, in its first application, the device is part of an open and modular monitoring system enabling the sensing of chemical compounds such as toxic and essential Hg, Cd, Pb, As and Cu trace metal species, nutrients and species related to the carbon cycle, VOCs and potentially toxic algae classes (FP7

Altered expression of genes involved in GABAergic transmission and neuromodulation of granule cell activity in the cerebellum of schizophrenia patients.

Science.gov (United States)

Bullock, W Michael; Cardon, Karen; Bustillo, Juan; Roberts, Rosalinda C; Perrone-Bizzozero, Nora I

2008-12-01

Deficits in gamma-aminobutyric acid (GABA) signaling have been described in the prefrontal cortex, limbic system, and cerebellum in individuals with schizophrenia. The purpose of the present study was to further investigate cerebellar gene expression alterations as they relate to decreases in GABAergic transmission by examining the expression of GABAergic markers, N-methyl-d-aspartic-acid (NMDA) receptor subunits, and cerebellum neuromodulators in individuals with schizophrenia. Subjects were postmortem men with a diagnosis of schizophrenia (N=13) and a postmortem interval-matched non-psychiatric male comparison group (N=13). The authors utilized real-time-quantitative polymerase chain reaction (PCR) to measure mRNA levels of the following GABAergic markers: glutamic acid decarboxylase (GAD) 65 and 67; GABA plasma membrane transporter-1 (GAT-1); GABA type A (GABA(A)) receptor subunits alpha(6), beta(3), and delta; and parvalbumin. In addition, real-time-quantitative PCR was utilized to assess mRNA levels of the NMDA receptor (NR) subunits NR1, NR2-A, NR2-B, NR2-C, and NR2-D as well as the cerebellar neuromodulators glutamate receptor (GluR)-6, kainate-preferring glutamate receptor subunit-2 (KA2), metabotropic glutamate receptor (mGluR)-2 and mGluR3, and neuronal nitric oxide synthase. Measurements for mRNA levels were determined using lateral cerebellar hemisphere tissue from both schizophrenia and comparison subjects. Schizophrenia subjects showed significant decreases in mRNA levels of GAD(67), GAD(65), GAT-1, mGluR2, and neuronal nitric oxide synthase. Increases in GABA(A)-alpha(6 )and GABA(A)-delta as well as GluR6 and KA2 were also observed. Medication effects on the expression of the same genes were examined in rats treated with either haloperidol (Sprague-Dawley rats [N=16]) or clozapine (Long-Evans rats [N=20]). Both haloperidol and clozapine increased the levels of GAD(67) in the cerebellum and altered the expression of other cerebellar mRNAs. These

Does malaria epidemiology project Cameroon as `Africa in miniature'?

Indian Academy of Sciences (India)

Cameroon, a west-central African country with a ∼20 million population, is commonly regarded as 'Africa in miniature' due to the extensive biological and cultural diversities of whole Africa being present in a single-country setting. This country is inhabited by ancestral human lineages in unique eco-climatic conditions and ...

Spontaneous tension haemopneumothorax.

Science.gov (United States)

Patterson, Benjamin Oliver; Itam, Sarah; Probst, Fey

2008-10-31

We present a patient with sudden onset progressive shortness of breath and no history of trauma, who rapidly became haemodynamically compromised with a pneumothorax and pleural effusion seen on chest radiograph. He was treated for spontaneous tension pneumothorax but this was soon revealed to be a tension haemopneumothorax. He underwent urgent thoracotomy after persistent bleeding to explore an apical vascular abnormality seen on CT scanning. To our knowledge this is the first such case reported.Aetiology and current approach to spontaneous haemothorax are discussed briefly.

Hypocretin-1 (orexin A) prevents the effects of hypoxia/hypercapnia and enhances the GABAergic pathway from the lateral paragigantocellular nucleus to cardiac vagal neurons in the nucleus ambiguus.

Science.gov (United States)

Dergacheva, O; Philbin, K; Bateman, R; Mendelowitz, D

2011-02-23

Hypocretins (orexins) are hypothalamic neuropeptides that play a crucial role in regulating sleep/wake states and autonomic functions including parasympathetic cardiac activity. We have recently demonstrated stimulation of the lateral paragigantocellular nucleus (LPGi), the nucleus which is thought to play a role in rapid eye movement (REM) sleep control, activates an inhibitory pathway to preganglionic cardiac vagal neurons in the nucleus ambiguus (NA). In this study we test the hypothesis that hypocretin-1 modulates the inhibitory neurotransmission to cardiac vagal neurons evoked by stimulation of the LPGi using whole-cell patch-clamp recordings in an in vitro brain slice preparation from rats. Activation of hypocretin-1 receptors produced a dose-dependent and long-term facilitation of GABAergic postsynaptic currents evoked by electrical stimulation of the LPGi. Hypoxia/hypercapnia diminished LPGi-evoked GABAergic current in cardiac vagal neurons and this inhibition by hypoxia/hypercapnia was prevented by pre-application of hypocretin-1. The action of hypocretin-1 was blocked by the hypocretin-1 receptor antagonist SB-334867. Facilitation of LPGi-evoked GABAergic current in cardiac vagal neurons under both normal condition and during hypoxia/hypercapnia could be the mechanism by which hypocretin-1 affects parasympathetic cardiac function and heart rate during REM sleep. Furthermore, our findings indicate a new potential mechanism that might be involved in the cardiac arrhythmias, bradycardia, and sudden cardiac death that can occur during sleep. Copyright © 2011. Published by Elsevier Ltd.

Non-Invasive Evaluation of the GABAergic/Glutamatergic System in Autistic Patients Observed by MEGA-Editing Proton MR Spectroscopy Using a Clinical 3 Tesla Instrument

Science.gov (United States)

Harada, Masafumi; Taki, Masako M.; Nose, Ayumi; Kubo, Hitoshi; Mori, Kenji; Nishitani, Hiromu; Matsuda, Tsuyoshi

2011-01-01

Amino acids related to neurotransmitters and the GABAergic/glutamatergic system were measured using a 3 T-MRI instrument in 12 patients with autism and 10 normal controls. All measurements were performed in the frontal lobe (FL) and lenticular nuclei (LN) using a conventional sequence for n-acetyl aspartate (NAA) and glutamate (Glu), and the…

INSTRUMENTAL MINIATURES BY THE COMPOSER GHEORGHE NEAGA: BETWEEN THE OLD AND THE NEW

Directory of Open Access Journals (Sweden)

CHICIUC NATALIA

2016-12-01

Full Text Available The miniature occupies an important place in Gheorghe Neaga’s instrumental chamber repertoire. Th e number of his small creations is impressive, being found both in the teaching repertoire of artistic education institutions and in the artistsinstrumentalists’ concert repertoire. Dedicated to piano, violin and piano or other instruments, the pieces refl ect in a perfect measure the author’s artistic predilections, more or less infl uenced by the evolution of compositional techniques. On this line, the proposed objective in this article is to examine some unelucidated miniatures through the old-new binomial spectrum.

A Molecular Diagnostic Test for Persistent Müllerian Duct Syndrome in Miniature Schnauzer Dogs

OpenAIRE

Pujar, S.; Meyers-Wallen, V.N.

2009-01-01

In persistent Müllerian duct syndrome (PMDS), Müllerian ducts fail to regress in males during sexual differentiation. In the canine miniature schnauzer model, PMDS is caused by a C to T transition in exon 3 of the Müllerian inhibiting substance type II receptor (MISRII), which introduces a DdeI restriction site. Here we report a molecular diagnostic test for PMDS in the miniature schnauzer to identify affected dogs and carriers. As our test results suggest that the mutation is identical by de...

Electric field distribution and current emission in a miniaturized geometrical diode

Science.gov (United States)

Lin, Jinpu; Wong, Patrick Y.; Yang, Penglu; Lau, Y. Y.; Tang, W.; Zhang, Peng

2017-06-01

We study the electric field distribution and current emission in a miniaturized geometrical diode. Using Schwarz-Christoffel transformation, we calculate exactly the electric field inside a finite vacuum cathode-anode (A-K) gap with a single trapezoid protrusion on one of the electrode surfaces. It is found that there is a strong field enhancement on both electrodes near the protrusion, when the ratio of the A-K gap distance to the protrusion height d /h spot checked against COMSOL simulations. We calculate the effective field enhancement factor for the field emission current, by integrating the local Fowler-Nordheim current density along the electrode surfaces. We systematically examine the electric field enhancement and the current rectification of the miniaturized geometrical diode for various geometric dimensions and applied electric fields.

Research and Development of Miniaturized Fuel Evaporation Closed Chamber for Motorcycle

Directory of Open Access Journals (Sweden)

Hong Bin

2016-01-01

Full Text Available With the increasingly serious environmental pollution, pollution emissions of motorcycles had gradually been concerned in all developed countries. But the fuel evaporative emissions had not attracted sufficient attention and its test equipment was far from perfect. Thus, this paper addressed the miniaturized problems of closed chamber. On the basis of analyzing fuel evaporative emission regulations and the features of closed room, technical solutions are determined and a prototype was successfully developed. The paper successfully resolved the seal problem and innovatively developed the pressure balance system and the temperature and humidity regulation system. After experimental verification, the prototype had reliable performance and stable operation. And it met the requirements of the relevant standards and it was also equivalent to imported equipments. Thus, this paper successfully resolved the miniaturized problems of closed chamber.

Discovery of skin alkaloids in a miniaturized eleutherodactylid frog from Cuba.

Science.gov (United States)

Rodríguez, Ariel; Poth, Dennis; Schulz, Stefan; Vences, Miguel

2011-06-23

Four phylogenetically independent lineages of frogs are currently known to sequester lipid-soluble skin alkaloids for which a dietary source has been demonstrated. We report here a remarkable fifth such instance, in Eleutherodactylus iberia and Eleutherodactylus orientalis, two species of miniaturized frogs of the family Eleutherodactylidae from Cuba. Six pumiliotoxins and two indolizidines were found in E. iberia, one of the smallest frogs in the world and characterized by a contrasting colour pattern for which we hypothesize an aposematic function. Analyses of stomach content indicated a numerical prevalence of mites with an important proportion of oribatids-a group of arthropods known to contain one of the pumiliotoxins detected in E. iberia. This suggests that miniaturization and specialization to small prey may have favoured the acquisition of dietary skin alkaloids in these amphibians.

Diagnosis of chronic active hepatitis in a miniature schnauzer.

Science.gov (United States)

Hendrix, Alana D

2004-09-01

A 12-year-old male castrated miniature schnauzer was presented with a history of abdominal distension. Serum biochemical analysis and abdominal ultrasonography indicated hepatic disease. A wedge biopsy provided a diagnosis of chronic active hepatitis. A therapeutic regime was initiated to improve the quality of life and slow the progression of this disease is described.

Diagnosis of chronic active hepatitis in a miniature schnauzer

OpenAIRE

Hendrix, Alana D.

2004-01-01

A 12-year-old male castrated miniature schnauzer was presented with a history of abdominal distension. Serum biochemical analysis and abdominal ultrasonography indicated hepatic disease. A wedge biopsy provided a diagnosis of chronic active hepatitis. A therapeutic regime was initiated to improve the quality of life and slow the progression of this disease is described.

Spontaneous tension haemopneumothorax

Directory of Open Access Journals (Sweden)

Itam Sarah

2008-10-01

Full Text Available Abstract We present a patient with sudden onset progressive shortness of breath and no history of trauma, who rapidly became haemodynamically compromised with a pneumothorax and pleural effusion seen on chest radiograph. He was treated for spontaneous tension pneumothorax but this was soon revealed to be a tension haemopneumothorax. He underwent urgent thoracotomy after persistent bleeding to explore an apical vascular abnormality seen on CT scanning. To our knowledge this is the first such case reported. Aetiology and current approach to spontaneous haemothorax are discussed briefly.

Fabrication of a miniature diamond grinding tool using a hybrid process of micro-EDM and co-deposition

International Nuclear Information System (INIS)

Chen, Shun-Tong; Lai, Yun-Cheng; Liu, Ching-Chang

2008-01-01

A novel miniature diamond grinding tool usable for the precise micro-grinding of miniature parts is presented. A hybrid process that combines 'micro-EDM' with 'precision co-deposition' is proposed. The metal substrate is micro-EDMed to a 50 µm diameter and micro diamonds with 0–2 µm grains are 'electroformed' on the substrate surface, producing a miniature multilayered grinding tool. Nickel and diamond act as binders and cutters, respectively. A partition plate with an array of drilled holes is designed to ensure good convection in the electroforming solution. The dispersion of diamond grains and displacement of nickel ions are noticeably improved. A miniature funnel mould enables the diamond grains to converge towards the cathode to increase their deposition probability on the substrate, thereby improving their distribution on the substrate surface. A micro ZrO 2 ceramic ferrule is finely ground by the developed grinding tool and then yields a surface roughness of R a = 0.085 µm. The proposed approach is applied during the final machining process

Spontaneous compactification to homogeneous spaces

International Nuclear Information System (INIS)

Mourao, J.M.

1988-01-01

The spontaneous compactification of extra dimensions to compact homogeneous spaces is studied. The methods developed within the framework of coset space dimensional reduction scheme and the most general form of invariant metrics are used to find solutions of spontaneous compactification equations

Detection of cryoglobulins in serum of Caspian miniature horse

Directory of Open Access Journals (Sweden)

Atyabi, N,

2012-06-01

Full Text Available Blood samples were collected from 20 healthy miniature Caspian horses at 37 °C. Isolation of cryoglobulin was performed based on a standard method in present study. Harvested sera were kept at 4 °C for two hours and then examined for cryoglubolin. Four serum samples containing precipitate Suspicious of containing cryoglobulin were selected. Subsequently serum protein electrophoresis was performed on normal serum samples and also on four serum samples containing precipitates using an automated electrophoresis system on cellulose acetate strips. In addition Ig isotypes detection (IgG, IgM and IgA was performed on both precipitates and serum containing precipitates using single radio immunediffusion method (SRID. A narrow-based peak on gamma region of precipitate acetate cellulose strips was observed. Precipitate concentrations were strikingly higher than normal concentration of serum immuneglobulins. It can be suggested that cryoglobulin concentration in a proportion of Caspian miniature horse is higher than other equides may be in relation with animal susceptibility to neoplasias such as lymphoma and leukemia.

Miniaturized Optical Tweezers Through Fiber-End Microfabrication

KAUST Repository

Liberale, Carlo; Cojoc, Gheorghe; Rajamanickam, Vijayakumar; Ferrara, Lorenzo; Bragheri, Francesca; Minzioni, Paolo; Perozziello, Gerardo; Candeloro, Patrizio; Cristiani, Ilaria; Di Fabrizio, Enzo M.

2014-01-01

Optical tweezers represent a powerful tool for a variety of applications both in biology and in physics, and their miniaturization and full integration is of great interest so as to reduce size (towards portable systems), and to minimize the required intervention from the operator. Optical fibers represent a natural solution to achieve this goal, and here we review the realization of single-fiber optical tweezers able to create a purely optical three-dimensional trap. © Springer International Publishing Switzerland 2015.

Miniaturized Optical Tweezers Through Fiber-End Microfabrication

KAUST Repository

Liberale, Carlo

2014-07-30

Optical tweezers represent a powerful tool for a variety of applications both in biology and in physics, and their miniaturization and full integration is of great interest so as to reduce size (towards portable systems), and to minimize the required intervention from the operator. Optical fibers represent a natural solution to achieve this goal, and here we review the realization of single-fiber optical tweezers able to create a purely optical three-dimensional trap. © Springer International Publishing Switzerland 2015.

Calcification of the intervertebral discs and curvature of the radius and ulna: A radiographic survey of Finnish miniature dachshunds

International Nuclear Information System (INIS)

Lappalainen, A.; Norrgaard, M.; Alm, K.; Snellman, M.; Laitinen, O.

2001-01-01

The vertebral column of 124 randomly selected miniature dachshunds, representing 4.5% of the population registered by the Finnish Kennel Club during the years 1988 to 1996, were radiographed. The front legs were also radiographed in order to evaluate the curvature of the radius and ulna. Calcified discs were found in 75.9% of the longhaired miniature dachshunds and in 86.7% of the wirehaired ones. The occurrence of signs associated with IDD was 16.5% in longhaired and 15.6% in wirehaired miniature dachshunds. The occurrence of signs of IDD in dogs with calcified discs was 20.0% and 17.9% in longhaired and wirehaired miniature dachshunds, respectively. In dogs without calcifications only one dog showed signs of IDD. The curvature of the radius and the ulna did not differ between the dogs with signs of IDD and the healthy ones, or between the dogs with and without intervertebral calcifications. Our results indicate that radiographic eradication based on the presence of intervertebral calcifications is not suitable for breeding purposes for the Finnish miniature dachshund population because the percentage of dogs without calcifications is small

Case of spontaneous ventriculocisternostomy

Energy Technology Data Exchange (ETDEWEB)

Yamane, Kanji; Yoshimoto, Hisanori; Harada, Kiyoshi; Uozumi, Tohru [Hiroshima Univ. (Japan). School of Medicine; Kuwabara, Satoshi

1983-05-01

The authors experienced a case of spontaneous ventriculocisternostomy diagnosed by CT scan with metrizamide and Conray. Patient was 23-year-old male who had been in good health until one month before admission, when he began to have headache and tinnitus. He noticed bilateral visual acuity was decreased about one week before admission and vomiting appeared two days before admission. He was admitted to our hospital because of bilateral papilledema and remarkable hydrocephalus diagnosed by CT scan. On admission, no abnormal neurological signs except for bilateral papilledema were noted. Immediately, right ventricular drainage was performed. Pressure of the ventricle was over 300mmH/sub 2/O and CSF was clear. PVG and PEG disclosed an another cavity behind the third ventricle, which was communicated with the third ventricle, and occlusion of aqueduct of Sylvius. Metrizamide CT scan and Conray CT scan showed a communication between this cavity and quadrigeminal and supracerebellar cisterns. On these neuroradiological findings, the diagnosis of obstructive hydrocephalus due to benign aqueduct stenosis accompanied with spontaneous ventriculocisternostomy was obtained. Spontaneous ventriculocisternostomy was noticed to produce arrest of hydrocephalus, but with our case, spontaneous regression of such symptoms did not appeared. By surgical ventriculocisternostomy (method by Torkildsen, Dandy, or Scarff), arrest of hydrocephalus was seen in about 50 to 70 per cent, which was the same results as those of spontaneous ventriculocisternostomy. It is concluded that VP shunt or VA shunt is thought to be better treatment of obstructive hydrocephalus than the various kinds of surgical ventriculocisternostomy.

Spontaneous Intracranial Hypotension without Orthostatic Headache

Directory of Open Access Journals (Sweden)

Tülay Kansu

2009-03-01

Full Text Available We report 2 cases of spontaneous intracranial hypotension that presented with unilateral abducens nerve palsy, without orthostatic headache. While sixth nerve palsies improved without any intervention, subdural hematoma was detected with magnetic resonance imaging. We conclude that headache may be absent in spontaneous intracranial hypotension and spontaneous improvement of sixth nerve palsy can occur, even after the development of a subdural hematoma

Miniature Bioprocess Array: A Platform for Quantitative Physiology and Bioprocess Optimization

National Research Council Canada - National Science Library

Keasling, Jay

2002-01-01

.... The miniature bioprocess array is based on an array of 150-microliters wells, each one of which incorporates MEMS for the closed-loop control of cell culture parameters such as temperature, pH, and dissolved oxygen...

GABAergic Neurons in the Rat Medial Septal Complex Express Relaxin-3 Receptor (RXFP3 mRNA

Directory of Open Access Journals (Sweden)

Hector Albert-Gascó

2018-01-01

Full Text Available The medial septum (MS complex modulates hippocampal function and related behaviors. Septohippocampal projections promote and control different forms of hippocampal synchronization. Specifically, GABAergic and cholinergic projections targeting the hippocampal formation from the MS provide bursting discharges to promote theta rhythm, or tonic activity to promote gamma oscillations. In turn, the MS is targeted by ascending projections from the hypothalamus and brainstem. One of these projections arises from the nucleus incertus in the pontine tegmentum, which contains GABA neurons that co-express the neuropeptide relaxin-3 (Rln3. Both stimulation of the nucleus incertus and septal infusion of Rln3 receptor agonist peptides promotes hippocampal theta rhythm. The Gi/o-protein-coupled receptor, relaxin-family peptide receptor 3 (RXFP3, is the cognate receptor for Rln3 and identification of the transmitter phenotype of neurons expressing RXFP3 in the septohippocampal system can provide further insights into the role of Rln3 transmission in the promotion of septohippocampal theta rhythm. Therefore, we used RNAscope multiplex in situ hybridization to characterize the septal neurons expressing Rxfp3 mRNA in the rat. Our results demonstrate that Rxfp3 mRNA is abundantly expressed in vesicular GABA transporter (vGAT mRNA- and parvalbumin (PV mRNA-positive GABA neurons in MS, whereas ChAT mRNA-positive acetylcholine neurons lack Rxfp3 mRNA. Approximately 75% of Rxfp3 mRNA-positive neurons expressed vGAT mRNA (and 22% were PV mRNA-positive, while the remaining 25% expressed Rxfp3 mRNA only, consistent with a potential glutamatergic phenotype. Similar proportions were observed in the posterior septum. The occurrence of RXFP3 in PV-positive GABAergic neurons gives support to a role for the Rln3-RXFP3 system in septohippocampal theta rhythm.

Spontaneous intraorbital hematoma: case report

Directory of Open Access Journals (Sweden)

Vinodan Paramanathan

2010-12-01

Full Text Available Vinodan Paramanathan, Ardalan ZolnourianQueen's Hospital NHS Foundation Trust, Burton on Trent, Staffordshire DE13 0RB, UKAbstract: Spontaneous intraorbital hematoma is an uncommon clinical entity seen in ophthalmology practice. It is poorly represented in the literature. Current evidence attributes it to orbital trauma, neoplasm, vascular malformations, acute sinusitis, and systemic abnormalities. A 65-year-old female presented with spontaneous intraorbital hematoma manifesting as severe ocular pains, eyelid edema, proptosis, and diplopia, without a history of trauma. Computer tomography demonstrated a fairly well defined extraconal lesion with opacification of the paranasal sinuses. The principal differential based on all findings was that of a spreading sinus infection and an extraconal tumor. An unprecedented finding of a spontaneous orbital hematoma was discovered when the patient was taken to theater. We discuss the rarity of this condition and its management.Keywords: hemorrhage, ophthalmology, spontaneous, intra-orbital, hematoma

Development of a novel miniature detonation-driven shock tube assembly that uses in situ generated oxyhydrogen mixture

International Nuclear Information System (INIS)

Janardhanraj, S.; Jagadeesh, G.

2016-01-01

A novel concept to generate miniature shockwaves in a safe, repeatable, and controllable manner in laboratory confinements using an in situ oxyhydrogen generator has been proposed and demonstrated. This method proves to be more advantageous than existing methods because there is flexibility to vary strength of the shockwave, there is no need for storage of high pressure gases, and there is minimal waste disposal. The required amount of oxyhydrogen mixture is generated using alkaline electrolysis that produces hydrogen and oxygen gases in stoichiometric quantity. The rate of oxyhydrogen mixture production for the newly designed oxyhydrogen generator is found to be around 8 ml/s experimentally. The oxyhydrogen generator is connected to the driver section of a specially designed 10 mm square miniature shock tube assembly. A numerical code that uses CANTERA software package is used to predict the properties of the driver gas in the miniature shock tube. This prediction along with the 1-D shock tube theory is used to calculate the properties of the generated shockwave and matches reasonably well with the experimentally obtained values for oxyhydrogen mixture fill pressures less than 2.5 bars. The miniature shock tube employs a modified tri-clover clamp assembly to facilitate quick changing of diaphragm and replaces the more cumbersome nut and bolt system of fastening components. The versatile nature of oxyhydrogen detonation-driven miniature shock tube opens up new horizons for shockwave-assisted interdisciplinary applications.

Development of a novel miniature detonation-driven shock tube assembly that uses in situ generated oxyhydrogen mixture

Energy Technology Data Exchange (ETDEWEB)

Janardhanraj, S.; Jagadeesh, G., E-mail: jaggie@aero.iisc.ernet.in [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India)

2016-08-15

A novel concept to generate miniature shockwaves in a safe, repeatable, and controllable manner in laboratory confinements using an in situ oxyhydrogen generator has been proposed and demonstrated. This method proves to be more advantageous than existing methods because there is flexibility to vary strength of the shockwave, there is no need for storage of high pressure gases, and there is minimal waste disposal. The required amount of oxyhydrogen mixture is generated using alkaline electrolysis that produces hydrogen and oxygen gases in stoichiometric quantity. The rate of oxyhydrogen mixture production for the newly designed oxyhydrogen generator is found to be around 8 ml/s experimentally. The oxyhydrogen generator is connected to the driver section of a specially designed 10 mm square miniature shock tube assembly. A numerical code that uses CANTERA software package is used to predict the properties of the driver gas in the miniature shock tube. This prediction along with the 1-D shock tube theory is used to calculate the properties of the generated shockwave and matches reasonably well with the experimentally obtained values for oxyhydrogen mixture fill pressures less than 2.5 bars. The miniature shock tube employs a modified tri-clover clamp assembly to facilitate quick changing of diaphragm and replaces the more cumbersome nut and bolt system of fastening components. The versatile nature of oxyhydrogen detonation-driven miniature shock tube opens up new horizons for shockwave-assisted interdisciplinary applications.

Verification of a CT scanner using a miniature step gauge

DEFF Research Database (Denmark)

Cantatore, Angela; Andreasen, J.L.; Carmignato, S.

2011-01-01

The work deals with performance verification of a CT scanner using a 42mm miniature replica step gauge developed for optical scanner verification. Errors quantification and optimization of CT system set-up in terms of resolution and measurement accuracy are fundamental for use of CT scanning...

Model-based tracking of miniaturized grippers using particle swarm optimization

NARCIS (Netherlands)

Scheggi, Stefano; Yoon, ChangKyu; Gracias, David H.; Misra, Sarthak

2016-01-01

Micro-sized agents can benefit robotic minimally invasive surgery since they can be inserted into the human body and use natural pathways such as arteries and veins or the gastrointestinal tract, to reach their target for drug delivery or diagnosis. Recently, miniaturized agents with shape-changing

Molecular and Electrophysiological Characterization of GABAergic Interneurons Expressing the Transcription Factor COUP-TFII in the Adult Human Temporal Cortex

Science.gov (United States)

Varga, Csaba; Tamas, Gabor; Barzo, Pal; Olah, Szabolcs; Somogyi, Peter

2015-01-01

Transcription factors contribute to the differentiation of cortical neurons, orchestrate specific interneuronal circuits, and define synaptic relationships. We have investigated neurons expressing chicken ovalbumin upstream promoter transcription factor II (COUP-TFII), which plays a role in the migration of GABAergic neurons. Whole-cell, patch-clamp recording in vitro combined with colocalization of molecular cell markers in the adult cortex differentiates distinct interneurons. The majority of strongly COUP-TFII-expressing neurons were in layers I–III. Most calretinin (CR) and/or cholecystokinin- (CCK) and/or reelin-positive interneurons were also COUP-TFII-positive. CR-, CCK-, or reelin-positive neurons formed 80%, 20%, or 17% of COUP-TFII-positive interneurons, respectively. About half of COUP-TFII-/CCK-positive interneurons were CR-positive, a quarter of them reelin-positive, but none expressed both. Interneurons positive for COUP-TFII fired irregular, accommodating and adapting trains of action potentials (APs) and innervated mostly small dendritic shafts and rarely spines or somata. Paired recording showed that a calretinin-/COUP-TFII-positive interneuron elicited inhibitory postsynaptic potentials (IPSPs) in a reciprocally connected pyramidal cell. Calbindin, somatostatin, or parvalbumin-immunoreactive interneurons and most pyramidal cells express no immunohistochemically detectable COUP-TFII. In layers V and VI, some pyramidal cells expressed a low level of COUP-TFII in the nucleus. In conclusion, COUP-TFII is expressed in a diverse subset of GABAergic interneurons predominantly innervating small dendritic shafts originating from both interneurons and pyramidal cells. PMID:25787832

Screening for spontaneous preterm birth

NARCIS (Netherlands)

van Os, M.A.; van Dam, A.J.E.M.

2015-01-01

Preterm birth is the most important cause of perinatal morbidity and mortality worldwide. In this thesis studies on spontaneous preterm birth are presented. The main objective was to investigate the predictive capacity of mid-trimester cervical length measurement for spontaneous preterm birth in a

Biosensing with Paper-Based Miniaturized Printed Electrodes–A Modern Trend

Directory of Open Access Journals (Sweden)

Célia M. Silveira

2016-09-01

Full Text Available From the bench-mark work on microfluidics from the Whitesides’s group in 2007, paper technology has experienced significant growth, particularly regarding applications in biomedical research and clinical diagnostics. Besides the structural properties supporting microfluidics, other advantageous features of paper materials, including their versatility, disposability and low cost, show off the great potential for the development of advanced and eco-friendly analytical tools. Consequently, paper was quickly employed in the field of electrochemical sensors, being an ideal material for producing custom, tailored and miniaturized devices. Stencil-, inkjet-, or screen-printing are the preferential techniques for electrode manufacturing. Not surprisingly, we witnessed a rapid increase in the number of publications on paper based screen-printed sensors at the turn of the past decade. Among the sensing strategies, various biosensors, coupling electrochemical detectors with biomolecules, have been proposed. This work provides a critical review and a discussion on the future progress of paper technology in the context of miniaturized printed electrochemical biosensors.

Biosensing with Paper-Based Miniaturized Printed Electrodes–A Modern Trend

Science.gov (United States)

Silveira, Célia M.; Monteiro, Tiago; Almeida, Maria Gabriela

2016-01-01

From the bench-mark work on microfluidics from the Whitesides’s group in 2007, paper technology has experienced significant growth, particularly regarding applications in biomedical research and clinical diagnostics. Besides the structural properties supporting microfluidics, other advantageous features of paper materials, including their versatility, disposability and low cost, show off the great potential for the development of advanced and eco-friendly analytical tools. Consequently, paper was quickly employed in the field of electrochemical sensors, being an ideal material for producing custom, tailored and miniaturized devices. Stencil-, inkjet-, or screen-printing are the preferential techniques for electrode manufacturing. Not surprisingly, we witnessed a rapid increase in the number of publications on paper based screen-printed sensors at the turn of the past decade. Among the sensing strategies, various biosensors, coupling electrochemical detectors with biomolecules, have been proposed. This work provides a critical review and a discussion on the future progress of paper technology in the context of miniaturized printed electrochemical biosensors. PMID:27690119

Biosensing with Paper-Based Miniaturized Printed Electrodes-A Modern Trend.

Science.gov (United States)

Silveira, Célia M; Monteiro, Tiago; Almeida, Maria Gabriela

2016-09-28

From the bench-mark work on microfluidics from the Whitesides's group in 2007, paper technology has experienced significant growth, particularly regarding applications in biomedical research and clinical diagnostics. Besides the structural properties supporting microfluidics, other advantageous features of paper materials, including their versatility, disposability and low cost, show off the great potential for the development of advanced and eco-friendly analytical tools. Consequently, paper was quickly employed in the field of electrochemical sensors, being an ideal material for producing custom, tailored and miniaturized devices. Stencil-, inkjet-, or screen-printing are the preferential techniques for electrode manufacturing. Not surprisingly, we witnessed a rapid increase in the number of publications on paper based screen-printed sensors at the turn of the past decade. Among the sensing strategies, various biosensors, coupling electrochemical detectors with biomolecules, have been proposed. This work provides a critical review and a discussion on the future progress of paper technology in the context of miniaturized printed electrochemical biosensors.

Early pregnancy angiogenic markers and spontaneous abortion

DEFF Research Database (Denmark)

Andersen, Louise B; Dechend, Ralf; Karumanchi, S Ananth

2016-01-01

BACKGROUND: Spontaneous abortion is the most commonly observed adverse pregnancy outcome. The angiogenic factors soluble Fms-like kinase 1 and placental growth factor are critical for normal pregnancy and may be associated to spontaneous abortion. OBJECTIVE: We investigated the association between...... maternal serum concentrations of soluble Fms-like kinase 1 and placental growth factor, and subsequent spontaneous abortion. STUDY DESIGN: In the prospective observational Odense Child Cohort, 1676 pregnant women donated serum in early pregnancy, gestational week ..., interquartile range 71-103). Concentrations of soluble Fms-like kinase 1 and placental growth factor were determined with novel automated assays. Spontaneous abortion was defined as complete or incomplete spontaneous abortion, missed abortion, or blighted ovum

Moessbauer study of miniature vessels from the Sican burial site of Huaca Loro

Energy Technology Data Exchange (ETDEWEB)

Cervantes, G., E-mail: gabriela.cervantes@pucp.pe [Pontificia Universidad Catolica del Peru (Peru); Shimada, I. [Southern Illinois University (United States); Haeusler, W.; Wagner, U.; Wagner, F. E. [Technische Universitaet Muenchen, Physik-Department E15 (Germany)

2011-11-15

Small handmade ceramic vessels are often found in large quantities in late pre-hispanic elite tombs on the north coast of Peru. These miniature vessels are of poor artistic and technologic qualities compared with other offerings found in tombs and have not received much attention. Our hypothesis is that these miniatures were made hastily by non-elite funeral attendants, which resulted in the observed formal and material variability. Here we report on the results of a systematic archaeological analysis of the shape and of archaeometric analyses by Moessbauer spectroscopy and XRD of the firing conditions of such vessels that were conducted to test the above hypothesis.

Miniature solid-state gas compressor

Science.gov (United States)

Lawless, W.N.; Cross, L.E.; Steyert, W.A.

1985-05-07

A miniature apparatus for compressing gases is disclosed in which an elastomer disposed between two opposing electrostrictive or piezoelectric ceramic blocks, or between a single electrostrictive or piezoelectric ceramic block and a rigid surface, is caused to extrude into or recede from a channel defined adjacent to the elastomer in response to application or removal of an electric field from the blocks. Individual cells of blocks and elastomer are connected to effect a gas compression by peristaltic activation of the individual cells. The apparatus is self-valving in that the first and last cells operate as inlet and outlet valves, respectively. Preferred electrostrictive and piezoelectric ceramic materials are disclosed, and an alternative, non-peristaltic embodiment of the apparatus is described. 9 figs.

High-Frequency Flush Mounted Miniature LOX Fiber-Optic Pressure Sensor, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Luna Innovations is teaming with the University of Alabama, Huntsville, to develop a miniature flush-mounted fiber-optic pressure sensor that will allow accurate,...

Analytical and Finite Element Modeling of Nanomembranes for Miniaturized, Continuous Hemodialysis

Directory of Open Access Journals (Sweden)

Tucker Burgin

2015-12-01

Full Text Available Hemodialysis involves large, periodic treatment doses using large-area membranes. If the permeability of dialysis membranes could be increased, it would reduce the necessary dialyzer size and could enable a wearable device that administers a continuous, low dose treatment of chronic kidney disease. This paper explores the application of ultrathin silicon membranes to this purpose, by way of analytical and finite element models of diffusive and convective transport of plasma solutes during hemodialysis, which we show to be predictive of experimental results. A proof-of-concept miniature nanomembrane dialyzer design is then proposed and analytically predicted to clear uremic toxins at near-ideal levels, as measured by several markers of dialysis adequacy. This work suggests the feasibility of miniature nanomembrane-based dialyzers that achieve therapeutic levels of uremic toxin clearance for patients with kidney failure.

Spontaneous emission by moving atoms

International Nuclear Information System (INIS)

Meystre, P.; Wilkens, M.

1994-01-01

It is well known that spontaneous emission is not an intrinsic atomic property, but rather results from the coupling of the atom to the vacuum modes of the electromagnetic field. As such, it can be modified by tailoring the electromagnetic environment into which the atom can radiate. This was already realized by Purcell, who noted that the spontaneous emission rate can be enhanced if the atom placed inside a cavity is resonant with one of the cavity is resonant with one of the cavity modes, and by Kleppner, who discussed the opposite case of inhibited spontaneous emission. It has also been recognized that spontaneous emission need not be an irreversible process. Indeed, a system consisting of a single atom coupled to a single mode of the electromagnetic field undergoes a periodic exchange of excitation between the atom and the field. This periodic exchange remains dominant as long as the strength of the coupling between the atom and a cavity mode is itself dominant. 23 refs., 6 figs

Synthesis of neurotransmitter GABA via the neuronal tricarboxylic acid cycle is elevated in rats with liver cirrhosis consistent with a high GABAergic tone in chronic hepatic encephalopathy

DEFF Research Database (Denmark)

Leke, Renata; Bak, Lasse Kristoffer; Iversen, Peter

2011-01-01

J. Neurochem. (2011) 117, 824-832. ABSTRACT: Hepatic encephalopathy (HE) is a neuropsychiatric complication to liver disease. It is known that ammonia plays a role in the pathogenesis of HE and disturbances in the GABAergic system have been related to HE. Synthesis of GABA occurs by decarboxylation...

The effect of gamma radiation on the stability of miniature reference electrodes

International Nuclear Information System (INIS)

Galuszka-Muga, B.; Muga, M.L.; Hanrahan, R.J.

2006-01-01

The design and fabrication of four types of miniature reference electrodes and their long term stability in a radiation field are described. Miniature versions of a saturated calomel electrode (MSCE), a silver/silver chloride electrode (MAG), a tungsten/tungsten oxide (MWO) and a copper/copper ion (MCU) electrode were tested in a 10 kGy/h (1 Mrad/h) radiation field for up to 30 days total at 25 and 40 o C. The latter two (MWO and MCU) varied appreciably over time periods of several hours whereas the former two (MSCE and MAG) varied less than 1 mV over periods of 6-8 h and are deemed suitable as reference electrodes for corrosion studies of systems immersed in a radiation field at elevated temperature

A low-power and high-precision miniaturized digital sun sensor

NARCIS (Netherlands)

Boer, B.M. de; Durkut, M.

2013-01-01

A prototype miniaturized digital sun sensor (miniDSS) was developed by TNO. It is expected to be launched on QuadSat for in-orbit demonstration. The single-chip sun sensor comprises an application specific integrated circuit (ASIC) on which an active pixel sensor (APS), read-out and processing

A Case of Multiple Spontaneous Keloid Scars

Directory of Open Access Journals (Sweden)

Abdulhadi Jfri

2015-07-01

Full Text Available Keloid scars result from an abnormal healing response to cutaneous injury or inflammation that extends beyond the borders of the original wound. Spontaneous keloid scars forming in the absence of any previous trauma or surgical procedure are rare. Certain syndromes have been associated with this phenomenon, and few reports have discussed the evidence of single spontaneous keloid scar, which raises the question whether they are really spontaneous. Here, we present a 27-year-old mentally retarded single female with orbital hypertelorism, broad nasal bridge, repaired cleft lip and high-arched palate who presented with progressive multiple spontaneous keloid scars in different parts of her body which were confirmed histologically by the presence of typical keloidal collagen. This report supports the fact that keloid scars can appear spontaneously and are possibly linked to a genetic factor. Furthermore, it describes a new presentation of spontaneous keloid scars in the form of multiple large lesions in different sites of the body.

Miniaturized Planar Room Temperature Ionic Liquid Electrochemical Gas Sensor for Rapid Multiple Gas Pollutants Monitoring.

Science.gov (United States)

Wan, Hao; Yin, Heyu; Lin, Lu; Zeng, Xiangqun; Mason, Andrew J

2018-02-01

The growing impact of airborne pollutants and explosive gases on human health and occupational safety has escalated the demand of sensors to monitor hazardous gases. This paper presents a new miniaturized planar electrochemical gas sensor for rapid measurement of multiple gaseous hazards. The gas sensor features a porous polytetrafluoroethylene substrate that enables fast gas diffusion and room temperature ionic liquid as the electrolyte. Metal sputtering was utilized for platinum electrodes fabrication to enhance adhesion between the electrodes and the substrate. Together with carefully selected electrochemical methods, the miniaturized gas sensor is capable of measuring multiple gases including oxygen, methane, ozone and sulfur dioxide that are important to human health and safety. Compared to its manually-assembled Clark-cell predecessor, this sensor provides better sensitivity, linearity and repeatability, as validated for oxygen monitoring. With solid performance, fast response and miniaturized size, this sensor is promising for deployment in wearable devices for real-time point-of-exposure gas pollutant monitoring.

Ballistic tongue projection in a miniaturized salamander.

Science.gov (United States)

Deban, Stephen M; Bloom, Segall V

2018-05-20

Miniaturization of body size is often accompanied by peculiarities in morphology that can have functional consequences. We examined the feeding behavior and morphology of the miniaturized plethodontid salamander Thorius, one of the smallest vertebrates, to determine if its performance and biomechanics differ from those of its larger relatives. High-speed imaging and dynamics analysis of feeding at a range of temperatures show that tongue projection in Thorius macdougalli is ballistic and achieves accelerations of up to 600 G with low thermal sensitivity, indicating that tongue projection is powered by an elastic-recoil mechanism. Preceding ballistic projection is an unusual preparatory phase of tongue protrusion, which, like tongue retraction, shows lower performance and higher thermal sensitivity that are indicative of movement being powered directly by muscle shortening. The variability of tongue-projection kinematics and dynamics is comparable to larger ballistic-tongued plethodontids and reveals that Thorius is capable of modulating its tongue movements in response to prey distance. Morphological examination revealed that T. macdougalli possesses a reduced number of myofibers in the tongue muscles, a large projector muscle mass relative to tongue mass, and an unusual folding of the tongue skeleton, compared with larger relatives. Nonetheless, T. macdougalli retains the elaborated collagen aponeuroses in the projector muscle that store elastic energy and a tongue skeleton that is free of direct myofiber insertion, two features that appear to be essential for ballistic tongue projection in salamanders. © 2018 Wiley Periodicals, Inc.

Capillary filling of miniaturized sources for electrospray mass spectrometry

International Nuclear Information System (INIS)

Arscott, Steve; Gaudet, Matthieu; Brinkmann, Martin; Ashcroft, Alison E; Blossey, Ralf

2006-01-01

Capillary slot-based emitter tips are a novel tool for use in electrospray ionization-mass spectrometry of large biomolecules. We have performed a combined theoretical and experimental study of capillary filling in micron-sized slots with the aim of developing a rational design procedure for miniaturized electrospray sources, ultimately enabling the integration of ESI into laboratory-on-a-chip devices

Release of fission products from miniature fuel plates at elevated temperature

International Nuclear Information System (INIS)

Posey, J.C.

1982-01-01

Three miniature fuel plates were tested at progressively higher temperatures. A U 3 Si plated blistered and released fission gases at 500 0 C. Two U 3 O 8 filled plates blistered and released fission gases at 550 0 C

Flame-in-gas-shield and miniature diffusion flame hydride atomizers for atomic fluorescence spectrometry: optimization and comparison

International Nuclear Information System (INIS)

Marschner, Karel; Musil, Stanislav; Dědina, Jiří

2015-01-01

A detailed optimization of relevant experimental parameters of two hydride atomizers for atomic fluorescence spectrometry: flame-in-gas-shield atomizer with a two-channel shielding unit and a standard atomizer for atomic fluorescence spectrometry, miniature diffusion flame, was performed. Arsine, generated by the reaction with NaBH 4 in a flow injection arrangement, was chosen as the model hydride. Analytical characteristics of both the atomizers (sensitivity, noise, limits of detection) were compared. Under optimum conditions sensitivity obtained with flame-in-gas-shield atomizer was approximately twice higher than with miniature diffusion flame. The additional advantage of flame-in-gas-shield atomizer is significantly lower flame emission resulting in a better signal to noise ratio. The resulting arsenic limits of detection for miniature diffusion flame and flame-in-gas-shield atomizer were 3.8 ng l −1 and 1.0 ng l −1 , respectively. - Highlights: • We optimized and compared two hydride atomizers for atomic fluorescence spectrometry. • Miniature diffusion flame and flame-in-gas-shield atomizer were optimized. • The limit of detection for arsenic was 1.0 ng l −1

Flame-in-gas-shield and miniature diffusion flame hydride atomizers for atomic fluorescence spectrometry: optimization and comparison

Energy Technology Data Exchange (ETDEWEB)

Marschner, Karel, E-mail: karel.marschner@biomed.cas.cz [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Charles University in Prague, Faculty of Science, Department of Analytical Chemistry, Albertov 8, 128 43 Prague (Czech Republic); Musil, Stanislav; Dědina, Jiří [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic)

2015-07-01

A detailed optimization of relevant experimental parameters of two hydride atomizers for atomic fluorescence spectrometry: flame-in-gas-shield atomizer with a two-channel shielding unit and a standard atomizer for atomic fluorescence spectrometry, miniature diffusion flame, was performed. Arsine, generated by the reaction with NaBH{sub 4} in a flow injection arrangement, was chosen as the model hydride. Analytical characteristics of both the atomizers (sensitivity, noise, limits of detection) were compared. Under optimum conditions sensitivity obtained with flame-in-gas-shield atomizer was approximately twice higher than with miniature diffusion flame. The additional advantage of flame-in-gas-shield atomizer is significantly lower flame emission resulting in a better signal to noise ratio. The resulting arsenic limits of detection for miniature diffusion flame and flame-in-gas-shield atomizer were 3.8 ng l{sup −1} and 1.0 ng l{sup −1}, respectively. - Highlights: • We optimized and compared two hydride atomizers for atomic fluorescence spectrometry. • Miniature diffusion flame and flame-in-gas-shield atomizer were optimized. • The limit of detection for arsenic was 1.0 ng l{sup −1}.

Miniature Ground Penetrating Radar, CRUX GPR

Science.gov (United States)

Kim, Soon Sam; Carnes, Steven R.; Haldemann, Albert F.; Ulmer, Christopher T.; Ng, Eddie; Arcone, Steven A.

2006-01-01

Under NASA instrument development programs (PIDDP 2000-2002, MIPD 2003-2005, ESR and T, 2005) we have been developing miniature ground penetrating radars (GPR) for use in mapping subsurface stratigraphy from planetary rovers for Mars and lunar applications. The Mars GPR is for deeper penetration (up to 50 m depth) into the Martian subsurface at moderate resolution (0.5 m) for a geological characterization. As a part of the CRUX (Construction and Resource Utilization Explorer) instrument suite, the CRUX GPR is optimized for a lunar prospecting application. It will have shallower penetration (5 m depth) with higher resolution (10 cm) for construction operations including ISRU (in-situ resource utilization).

Uniform LED illuminator for miniature displays

Science.gov (United States)

Medvedev, Vladimir; Pelka, David G.; Parkyn, William A.

1998-10-01

The Total Internally Reflecting (TIR) lens is a faceted structure composed of prismatic elements that collect a source's light over a much larger angular range than a conventional Fresnel lens. It has been successfully applied to the efficient collimation of light from incandescent and fluorescent lamps, and from light-emitting diodes (LEDs). A novel LED-powered collimating backlight is presented here, for uniformly illuminating 0.25'-diagonal miniature liquid- crystal displays, which are a burgeoning market for pagers, cellular phones, digital cameras, camcorders, and virtual- reality displays. The backlight lens consists of a central dual-asphere refracting section and an outer TIR section, properly curved with a curved exit face.

The laboratory test rig with miniature jet engine to research aviation fuels combustion process

Directory of Open Access Journals (Sweden)

Gawron Bartosz

2015-12-01

Full Text Available This article presents laboratory test rig with a miniature turbojet engine (MiniJETRig – Miniature Jet Engine Test Rig, that was built in the Air Force Institute of Technology. The test rig has been developed for research and development works aimed at modelling and investigating processes and phenomena occurring in full scale jet engines. In the article construction of a test rig is described, with a brief discussion on the functionality of each of its main components. Additionally examples of measurement results obtained during the realization of the initial tests have been included, presenting the capabilities of the test rig.

Spontaneous pneumothorax in silicotuberculosis of lung

International Nuclear Information System (INIS)

Kolenic, J.; Jurgova, T.; Zimacek, J.; Vajo, J.; Krchnavy, M.

1995-01-01

The authors describe the case of 62 years old man with the appearance of spontaneous pneumothorax, in whom the basic pulmonary disease was silicotuberculosis of the lung. At clinic of occupational diseases in Kosice have been evidence 965 cases of silicosis and silicotuberculosis. From 1971 they have now the first case of spontaneous pneumothorax. The authors make discussion about possible mechanical and biochemical factors, which cause relatively low incidence of spontaneous pneumothorax in silicosis of the lung. (authors)

Fabrication of applicator system of miniature X-ray tube based on carbon nanotubes for a skin cancer therapy

International Nuclear Information System (INIS)

Park, Han Beom; Kim, Hyun Jin; Lee, Ju Hyuk; Ha, Jun Mok; Cho, Sung Oh

2016-01-01

A miniature X-ray tube is a small X-ray generation device generally with a diameter of less than 10 mm. Because of the feasible installation in a spatially constrained area and the possibility of electrical on/off control, miniature X-ray tubes can be widely used for nondestructive X-ray radiography, hand held X-ray spectrometers, electric brachytherapy, and interstitial or intracavitary radiation therapy or imaging with the substitution of radioactive isotopes. Miniature X-ray tubes have been developed mostly using thermionic electron sources or secondary X-ray emission. The X-ray tube show excellent field emission properties and good X-ray spectrum. Also, the flattening filter was made to irradiate uniformly. The X-ray dose radial uniformities between installed flattening filter and non-installed flattening filter were measured. When flattening filter is equipped, X-ray uniformity was improved from higher than 20% to lower than 10%. As a result, the fabricated applicator system of the miniature X-ray tube using optimized flattening filter exhibited fairly excellent properties

Novel codrugs with GABAergic activity for dopamine delivery in the brain.

Science.gov (United States)

Denora, Nunzio; Cassano, Tommaso; Laquintana, Valentino; Lopalco, Antonio; Trapani, Adriana; Cimmino, Concetta Stefania; Laconca, Leonardo; Giuffrida, Andrea; Trapani, Giuseppe

2012-11-01

This study investigates the use of codrugs of the GABAergic agent 2-phenyl-imidazo[1,2-a]pyridinacetamide and dopamine (DA) or ethyl ester L-Dopa (LD) as a strategy to deliver DA and simultaneously activate GABA-receptors in the brain. For this purpose, both DA and LD ethyl ester were linked by carbamate bond to imidazo[1,2-a]pyridine acetamide moieties to yield two DA- and two LD-imidazopyridine derivatives. These compounds were evaluated in vitro to assess their stability, binding affinities and cell membrane transport, and in vivo to assess their bio-availability via microdialysis studies. The two DA derivatives were adequately stable in buffered solution, but underwent cleavage in diluted human serum. By contrast, the LD derivatives were unstable in buffered solution. Receptor binding studies showed that the DA-imidazopyridine carbamates had binding affinity for benzodiazepine receptors in the nanomolar range. Brain microdialysis experiments indicated that intraperitoneal administration of the DA derivatives sustained DA levels in rat striatum over a 4-h period. These results suggest that DA-imidazopyridine carbamates are new DA codrugs with potential application for DA replacement therapy. Copyright © 2012 Elsevier B.V. All rights reserved.

Laser weld reconstitution of conventional Charpy and Miniaturized Notch Test (MNT) specimens

International Nuclear Information System (INIS)

Manahan, M.P.; Williams, J.; Martukanitz, R.P.

1993-01-01

As nuclear power plants approach end-of-license (EOL) and consideration is given to license renewal, there is an ever increasing need to expand the amount of data obtainable from the original surveillance specimens. A laser welding technique to reconstitute broken Charpy specimens is being developed to produce both conventional and miniaturized Charpy specimens. This paper reports on early laser welding development efforts and summarizes previous proof-of-principle experiments on a 1/16 scale miniaturized Charpy test. In order to benchmark the laser welding procedure, the laser-reconstituted specimen data have been compared with the original specimen data. In addition, the microstructure after welding has been examined to ensure that the material in the vicinity of the notch is essentially unchanged after the welding process. Data which characterize the thermal transient during welding are obtained by attaching thermocouples to the specimens. Other important considerations include perturbation of the stress field near the notch, dynamic stress waves, and contact of the weld region with the tup. Precise control of welding parameters has been demonstrated, heat-affected zones as small as 0.25 mm can be achieved, and sufficient penetration depth can be obtained to enable welding thick sections (1T or greater) to yield conventional Charpy specimens or fracture toughness specimens and thin sections (∼5 mm) to yield Miniaturized Notch Test (MNT) specimens

Activity-dependent switch of GABAergic inhibition into glutamatergic excitation in astrocyte-neuron networks.

Science.gov (United States)

Perea, Gertrudis; Gómez, Ricardo; Mederos, Sara; Covelo, Ana; Ballesteros, Jesús J; Schlosser, Laura; Hernández-Vivanco, Alicia; Martín-Fernández, Mario; Quintana, Ruth; Rayan, Abdelrahman; Díez, Adolfo; Fuenzalida, Marco; Agarwal, Amit; Bergles, Dwight E; Bettler, Bernhard; Manahan-Vaughan, Denise; Martín, Eduardo D; Kirchhoff, Frank; Araque, Alfonso

2016-12-24

Interneurons are critical for proper neural network function and can activate Ca 2+ signaling in astrocytes. However, the impact of the interneuron-astrocyte signaling into neuronal network operation remains unknown. Using the simplest hippocampal Astrocyte-Neuron network, i.e., GABAergic interneuron, pyramidal neuron, single CA3-CA1 glutamatergic synapse, and astrocytes, we found that interneuron-astrocyte signaling dynamically affected excitatory neurotransmission in an activity- and time-dependent manner, and determined the sign (inhibition vs potentiation) of the GABA-mediated effects. While synaptic inhibition was mediated by GABA A receptors, potentiation involved astrocyte GABA B receptors, astrocytic glutamate release, and presynaptic metabotropic glutamate receptors. Using conditional astrocyte-specific GABA B receptor ( Gabbr1 ) knockout mice, we confirmed the glial source of the interneuron-induced potentiation, and demonstrated the involvement of astrocytes in hippocampal theta and gamma oscillations in vivo. Therefore, astrocytes decode interneuron activity and transform inhibitory into excitatory signals, contributing to the emergence of novel network properties resulting from the interneuron-astrocyte interplay.

High power VCSELs for miniature optical sensors

Science.gov (United States)

Geske, Jon; Wang, Chad; MacDougal, Michael; Stahl, Ron; Follman, David; Garrett, Henry; Meyrath, Todd; Snyder, Don; Golden, Eric; Wagener, Jeff; Foley, Jason

2010-02-01

Recent advances in Vertical-cavity Surface-emitting Laser (VCSEL) efficiency and packaging have opened up alternative applications for VCSELs that leverage their inherent advantages over light emitting diodes and edge-emitting lasers (EELs), such as low-divergence symmetric emission, wavelength stability, and inherent 2-D array fabrication. Improvements in reproducible highly efficient VCSELs have allowed VCSELs to be considered for high power and high brightness applications. In this talk, Aerius will discuss recent advances with Aerius' VCSELs and application of these VCSELs to miniature optical sensors such as rangefinders and illuminators.

Spontaneous pneumothorax in diffuse cystic lung diseases.

Science.gov (United States)

Cooley, Joseph; Lee, Yun Chor Gary; Gupta, Nishant

2017-07-01

Diffuse cystic lung diseases (DCLDs) are a heterogeneous group of disorders with varying pathophysiologic mechanisms that are characterized by the presence of air-filled lung cysts. These cysts are prone to rupture, leading to the development of recurrent spontaneous pneumothoraces. In this article, we review the epidemiology, clinical features, and management DCLD-associated spontaneous pneumothorax, with a focus on lymphangioleiomyomatosis, Birt-Hogg-Dubé syndrome, and pulmonary Langerhans cell histiocytosis. DCLDs are responsible for approximately 10% of apparent primary spontaneous pneumothoraces. Computed tomography screening for DCLDs (Birt-Hogg-Dubé syndrome, lymphangioleiomyomatosis, and pulmonary Langerhans cell histiocytosis) following the first spontaneous pneumothorax has recently been shown to be cost-effective and can help facilitate early diagnosis of the underlying disorders. Patients with DCLD-associated spontaneous pneumothorax have a very high rate of recurrence, and thus pleurodesis should be considered following the first episode of spontaneous pneumothorax in these patients, rather than waiting for a recurrent episode. Prior pleurodesis is not a contraindication to future lung transplant. Although DCLDs are uncommon, spontaneous pneumothorax is often the sentinel event that provides an opportunity for diagnosis. By understanding the burden and implications of pneumothoraces in DCLDs, clinicians can facilitate early diagnosis and appropriate management of the underlying disorders.

Dimensional and Structural Control of Silica Aerogel Membranes for Miniaturized Motionless Gas Pumps.

Science.gov (United States)

Zhao, Shanyu; Jiang, Bo; Maeder, Thomas; Muralt, Paul; Kim, Nayoung; Matam, Santhosh Kumar; Jeong, Eunho; Han, Yen-Lin; Koebel, Matthias M

2015-08-26

With growing public interest in portable electronics such as micro fuel cells, micro gas total analysis systems, and portable medical devices, the need for miniaturized air pumps with minimal electrical power consumption is on the rise. Thus, the development and downsizing of next-generation thermal transpiration gas pumps has been investigated intensively during the last decades. Such a system relies on a mesoporous membrane that generates a thermomolecular pressure gradient under the action of an applied temperature bias. However, the development of highly miniaturized active membrane materials with tailored porosity and optimized pumping performance remains a major challenge. Here we report a systematic study on the manufacturing of aerogel membranes using an optimized, minimal-shrinkage sol-gel process, leading to low thermal conductivity and high air conductance. This combination of properties results in superior performance for miniaturized thermomolecular air pump applications. The engineering of such aerogel membranes, which implies pore structure control and chemical surface modification, requires both chemical processing know-how and a detailed understanding of the influence of the material properties on the spatial flow rate density. Optimal pumping performance was found for devices with integrated membranes with a density of 0.062 g cm(-3) and an average pore size of 142.0 nm. Benchmarking of such low-density hydrophobic active aerogel membranes gave an air flow rate density of 3.85 sccm·cm(-2) at an operating temperature of 400 °C. Such a silica aerogel membrane based system has shown more than 50% higher pumping performance when compared to conventional transpiration pump membrane materials as well as the ability to withstand higher operating temperatures (up to 440 °C). This study highlights new perspectives for the development of miniaturized thermal transpiration air pumps while offering insights into the fundamentals of molecular pumping in

Scaling laws for free piston Stirling engine design: Benefits and challenges of miniaturization

International Nuclear Information System (INIS)

Formosa, Fabien; Fréchette, Luc G.

2013-01-01

This work explores the scaling effects for FPSE (free piston Stirling engines), which are known for their simple architecture and potentially high thermodynamic performances. Scaling laws are given and their potential for miniaturization is highlighted. A simple model which allows the design of the geometrical parameters of the heat exchangers, the regenerator and the masses of the pistons is proposed. It is based on the definition of six characteristic dimensionless groups. They are derived from the physics underlying the behavior of the free piston Stirling machine and their relevancy is backed up by comparisons between documented Stirling engines from the literature. Keeping constant values for each group throughout the scaling range theoretically ensures constant performance. The main losses of Stirling engine (heat conduction loss, reheat loss in the regenerator, pressure drop and gas-spring hysteresis) can be expressed as a function of the geometrical and operating parameters. Additionally, the consequences of leakage due to the manufacturing precision of pistons architectures are underlined. From the proposed scaling laws, potential power and efficiency of Stirling cycle engines at a millimeter scale can be anticipated. It appears that the power density increases with miniaturization. It is also shown that the dynamic masses related to the engine size are increased when scaling down and that the gap leakage presents the highest detrimental effects on the efficiency. These results call for dedicated architectures for micro-engines. - Highlights: • Similitude strategy is applied to Stirling engines and allows preliminary design. • New scaling laws are derived. • The power density can be increased with miniaturization. • The gap between the piston and casing is highly detrimental to the performances. • High engine operating pressure is required when miniaturizing