bluuebunny/crossref_metadata_2025_split huggingface dataset:
ZnO-CeO2 nanocomposite: efficient catalyst for the preparation of thieno[2,3-d]pyrimidin-4(3H)-one derivatives
Authors: Ghayour Farzaneh , Mohammad Shafiee Mohammad Reza , Ghashang Majid 
Published: April 2018

AbstractThe Zinc oxide-cerium oxide (ZnO-CeO2) nanocomposite was prepared by a coprecipitation method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and particle size distribution analysis. The XRD pattern shows the cubic phase of cerium oxide as the dominant phase. The FE-SEM images show the homogeneity distribution of zinc and cerium oxides in the sample. The mean particle size of the nanocomposite determined by dynamic light scattering technique was 58 nm. The catalytic activity of ZnO-CeO2nanocomposite was examined on the synthesis of thieno[2,3-d]pyrimidin-4(3H)-one derivatives. In all cases, the products were obtained in good to excellent yields.
Hopf-Pitchfork Bifurcation in a Symmetrically Conservative Two-Mass System with Delay
Authors: Sun Ye , Zhang Chunrui , Cai Yuting 
Published: April 2018

Abstract
A symmetrically conservative two-mass system with time delay is considered here. We analyse the influence of interaction coefficient and time delay on the Hopf-pitchfork bifurcation. The bifurcation diagrams and phase portraits are then obtained by computing the normal forms for the system in which, particularly, the unfolding form for case III is seldom given in delayed differential equations. Furthermore, we also find some interesting dynamical behaviours of the original system, such as the coexistence of two stable non-trivial equilibria and a pair of stable periodic orbits, which are verified both theoretically and numerically.
Comparison of Static and Dynamic Balance at Different Levels of Sport Competition in Professional and Junior Elite Soccer Players
Authors: Jadczak Łukasz , Grygorowicz Monika , Dzudziński Witold , Śliwowski Robert 
Published: April 2018

Abstract
Jadczak, Ł, Grygorowicz, M, Dzudziński, W, and Śliwowski, R. Comparison of static and dynamic balance at different levels of sport competition in professional and junior elite soccer players. J Strength Cond Res 33(12): 3384–3391, 2019—The purpose of this study was to compare body balance control and balance recovery strategies of professional football players, representing various sports levels in static (eyes open, eyes closed) and dynamic conditions, both on the dominant and nondominant leg. Three groups of professional and junior elite soccer players were investigated: a PRO group (n = 52), a U-21 group (n = 55), and a U-19 group (n = 47). The study of body balance control was performed using a Delos Postural Proprioceptive System measurement tool. The analysis of the results showed an effect of group (p < 0.01) and leg significance (p < 0.95) in the dynamic test. Three-way analysis of variance (3 [group] × 2 [leg] × 2 [eyes]) of static test data showed that the main effect of eyes (p < 0.0001), group (p < 0.0001), and leg (p = 0.0092) and the 2-way interaction of eyes × group (p = 0.0003) were significant. To represent statistical significance, the cutoff value was set to be p ≤ 0.005 for all measures. Our results indicate the importance of evaluation and monitoring of dynamic and static balance on both legs, which allows for a comprehensive comparison of body balance control and the balance recovery strategy depending on the represented sport level. Our study indicates that the higher the sport level of football players (the PRO group), the better their balance, which may indirectly contribute to the prevention of injuries and more effective performance of any actions directly related to the game.
Intrinsic Membrane Properties Underlying Spontaneous Tonic Firing in Neostriatal Cholinergic Interneurons
Authors: Bennett Ben D. , Callaway Joseph C. , Wilson Charles J. 
Published: April 2018

Neostriatal cholinergic interneurons produce spontaneous tonic firing in the absence of synaptic input. Perforated patch recording and whole-cell recording combined with calcium imaging were usedin vitroto identify the intrinsic membrane properties underlying endogenous excitability. Spontaneous firing was driven by the combined action of a sodium current and the hyperpolarization-activated cation current (Ih), which together ensured that there was no zero current point in the subthreshold voltage range. Blockade of sodium channels orIhestablished a stable subthreshold resting membrane potential. A tetrodotoxin-sensitive region of negative slope conductance was observed between approximately −60 mV and threshold (approximately −50 mV) and the h-current was activated at all subthreshold voltages.Calcium imaging experiments revealed that there was minimal calcium influx at subthreshold membrane potentials but that action potentials produced elevations of calcium in both the soma and dendrites. Spike-triggered calcium entry shaped the falling phase of the action potential waveform and activated calcium-dependent potassium channels. Blockade of big-conductance channels caused spike broadening. Application of apamin, which blocks small-conductance channels, abolished the slow spike afterhyperpolarization (AHP) and caused a transition to burst firing.In the absence of synaptic input, a range of tonic firing patterns are observed, suggesting that the characteristic spike sequences described for tonically active cholinergic neurons (TANs) recordedin vivoare intrinsic in origin. The pivotal role of the AHP in regulating spike patterning indicates that burst firing of TANsin vivocould arise from direct or indirect modulation of the AHP without requiring phasic synaptic input.
Representation of Acoustic Communication Signals by Insect Auditory Receptor Neurons
Authors: Machens Christian K. , Stemmler Martin B. , Prinz Petra , Krahe Rüdiger , Ronacher Bernhard , Herz Andreas V. M. 
Published: April 2018

Despite their simple auditory systems, some insect species recognize certain temporal aspects of acoustic stimuli with an acuity equal to that of vertebrates; however, the underlying neural mechanisms and coding schemes are only partially understood. In this study, we analyze the response characteristics of the peripheral auditory system of grasshoppers with special emphasis on the representation of species-specific communication signals. We use both natural calling songs and artificial random stimuli designed to focus on two low-order statistical properties of the songs: their typical time scales and the distribution of their modulation amplitudes.Based on stimulus reconstruction techniques and quantified within an information-theoretic framework, our data show that artificial stimuli with typical time scales of >40 msec can be read from single spike trains with high accuracy. Faster stimulus variations can be reconstructed only for behaviorally relevant amplitude distributions. The highest rates of information transmission (180 bits/sec) and the highest coding efficiencies (40%) are obtained for stimuli that capture both the time scales and amplitude distributions of natural songs.Use of multiple spike trains significantly improves the reconstruction of stimuli that vary on time scales <40 msec or feature amplitude distributions as occur when several grasshopper songs overlap. Signal-to-noise ratios obtained from the reconstructions of natural songs do not exceed those obtained from artificial stimuli with the same low-order statistical properties. We conclude that auditory receptor neurons are optimized to extract both the time scales and the amplitude distribution of natural songs. They are not optimized, however, to extract higher-order statistical properties of the song-specific rhythmic patterns.
Facilitation of Conditioned Fear Extinction by Systemic Administration or Intra-Amygdala Infusions of d-Cycloserine as Assessed with Fear-Potentiated Startle in Rats
Authors: Walker David L. , Ressler Kerry J. , Lu Kwok-Tung , Davis Michael 
Published: April 2018

NMDA receptor antagonists block conditioned fear extinction when injected systemically and also when infused directly into the amygdala. Here we evaluate the ability ofd-cycloserine (DCS), a partial agonist at the strychnine-insensitive glycine-recognition site on the NMDA receptor complex, to facilitate conditioned fear extinction after systemic administration or intra-amygdala infusions.Rats received 10 pairings of a 3.7 sec light and a 0.4 mA footshock (fear conditioning). Fear-potentiated startle (increased startle in the presence vs the absence of the light) was subsequently measured before and after 30, 60, or 90 presentations of the light without shock (extinction training). Thirty non-reinforced light presentations produced modest extinction, and 60 or 90 presentations produced nearly complete extinction (experiment 1). DCS injections (3.25, 15, or 30 mg/kg) before 30 non-reinforced light exposures dose-dependently enhanced extinction (experiment 2) but did not influence fear-potentiated startle in rats that did not receive extinction training (experiment 3). These effects were blocked by HA-966, an antagonist at the glycine-recognition site (experiment 4). Neither DCS nor HA-966 altered fear-potentiated startle when injected before testing (experiment 5). The effect of systemic administration was mimicked by intra-amygdala DCS (10 μg/side) infusions (experiment 6).These results indicate that treatments that promote NMDA receptor activity after either systemic or intra-amygdala administration promote the extinction of conditioned fear.
Cdk5/p35 Regulates Neurotransmitter Release through Phosphorylation and Downregulation of P/Q-Type Voltage-Dependent Calcium Channel Activity
Authors: Tomizawa Kazuhito , Ohta Jun , Matsushita Masayuki , Moriwaki Akiyoshi , Li Sheng-Tian , Takei Kohji , Matsui Hideki 
Published: April 2018

Cyclin-dependent kinase 5 (Cdk5) is a proline-directed serine/threonine kinase with close structural homology to the mitotic Cdks. The complex of Cdk5 and p35, the neuron-specific regulatory subunit of Cdk5, plays important roles in brain development, such as neuronal migration and neurite outgrowth. Moreover, Cdk5 is thought to be involved in the promotion of neurodegeneration in Alzheimer's disease.Cdk5 is abundant in mature neurons; however, its physiological functions in the adult brain are unknown. Here we show that Cdk5/p35 regulates neurotransmitter release in the presynaptic terminal. Both Cdk5 and p35 were abundant in the synaptosomes. Roscovitine, a specific inhibitor of Cdk5 in neurons, induced neurotransmitter release from the synaptosomes in response to membrane depolarization and enhanced the EPSP slopes in rat hippocampal slices. The electrophysiological study using each specific inhibitor of the voltage-dependent calcium channels (VDCCs) and calcium imaging revealed that roscovitine enhanced Ca2+influx from the P/Q-type VDCC. Moreover, Cdk5/p25 phosphorylated the intracellular loop connecting domains II and III (LII-III) between amino acid residues 724 and 981 of isoforms cloned from rat brain of the α1Asubunit of P/Q-type Ca2+channels. The phosphorylation inhibited the interaction of LII-IIIwith SNAP-25 and synaptotagmin I, which were plasma membrane solubleN-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (SNARE) proteins and were required for efficient neurotransmitter release. These results strongly suggest that Cdk5/p35 inhibits neurotransmitter release through the phosphorylation of P/Q-type VDCC and downregulation of the channel activity.
Variable Dopamine Release Probability and Short-Term Plasticity between Functional Domains of the Primate Striatum
Authors: Cragg Stephanie J. 
Published: April 2018

Release of the neuromodulator dopamine (DA) is critical to the control of locomotion, motivation, and reward. However, the probability of DA release is not well understood. Current understanding of neurotransmitter release probability in the CNS is limited to the conventional synaptic amino acid transmitters (e.g., glutamate and GABA). These fast neurotransmitters are released with a repertoire of probabilities according to synapse type, and these probabilities show activity-dependent plasticity according to synapse use. Synapses for neuromodulators such as DA, however, are designed for signaling that diverges temporally and spatially from that for fast neurotransmitters: DA receptors are exclusively metabotropic and at sites that extend to extrasynaptic locations and neighboring synapses.In this study, the release probability of DA was explored in real time in limbicversus motor-associated functional domains of the striatum of a primate (marmoset;Callithrix jacchus) using fast-scan voltammetry at a carbon-fiber microelectrode. We show that the probability of axonal DA release varies with striatal domain. Furthermore, release probability exhibits a short-term, activity-dependent plasticity that ranges from depression to facilitation in motor-through limbic-associated regions, respectively. Rapid plasticity does not result from metabotropic D2-like DA receptor activation or ionotropic GABAAreceptor effects but is dependent on Ca2+availability.These data reveal that rapid dynamics in DA release probability will participate in the transmission of the patterns and frequencies encoded by DA neuron action potential discharge. Furthermore, the regional variation in these features indicates that limbic-versus motor-associated DA neurons are permitted to generate diverse DA signals in response to a given firing pattern.
Early Odor Preference Learning in the Rat: Bidirectional Effects of cAMP Response Element-Binding Protein (CREB) and Mutant CREB Support a Causal Role for Phosphorylated CREB
Authors: Yuan Qi , Harley Carolyn W. , Darby-King Andrea , Neve Rachael L. , McLean John H. 
Published: April 2018

Early odor preference learning in rats is associated with increases of phosphorylated CREB (pCREB) in mitral cells of the olfactory bulb. In the present study, herpes simplex virus expressing CREB (HSV-CREB) and dominant-negative mutant CREB (HSV-mCREB) have been injected into the bulb to assess a causal role for CREB and pCREB in this model. Odor paired with stroking or with the β-adrenoceptor agonist isoproterenol produces odor approach 24 hr later. Isoproterenol-induced learning exhibits an inverted U curve dose-dependent learning relationship with both low and high doses failing to produce learning. pCREB increases have only been seen at the learning effective dose.In the present study, injection of an HSV vector expressing mutant CREB into the olfactory bulb prevented learning induced by stroking. Control HSV expressing LacZ was without effect. Expression of mutant CREB shifted the dose–learning curve for isoproterenol to the right such that a higher dose was required to induce learning. Expression of CREB shifted the dose-learning curve for isoproterenol to the left, with a lower dose now producing learning. As expected from this shift, CREB overexpression interfered with learning induced by stroking.When learning occurred, with either CREB or mutant CREB, pCREB was observed to be elevated relative to the nonlearning LacZ control groups. Unexpectedly, with odor plus stroking in the nonlearning CREB group, the level of pCREB was also higher than with odor plus stroking in LacZ controls that did learn.The data demonstrate a causal role for CREB and pCREB in early mammalian odor preference learning, reinforcing CREB as a “universal” memory molecule. They support evidence that CREB overexpression can be deleterious and suggest the hypothesis of an optimal pCREB window for learning.
Gap Junctions Mediate Bystander Cell Death in Developing Retina
Authors: Cusato Karen , Bosco Alejandra , Rozental Renato , Guimarães Cinthya A. , Reese Benjamin E. , Linden Rafael , Spray David C. 
Published: April 2018

During development of the retina, programmed cell death helps to establish the final size and distribution of various cell classes in distinct layers of the tissue. Here we show that dying cells in the developing ganglion and inner nuclear layers are clustered spatially and that gap junction inhibitors decrease the clustering of dying cells. To confirm the role of gap junctions in cell death, we induced targeted cell death via intracellular cytochromec(Cc) and examined the induced cells and their neighbors for apoptotic morphology or caspase-3 cleavage. These studies indicate that bystander killing extends to coupled cells.Quantitative studies of bystander killing were performed by scrape-loading retinas with Ccin the presence of rhodamine dextran (RD; to identify Cc-loaded cells) and by counting pyknotic cells in cryosections. Although only 1.5% of control scrape-loaded cells (RD alone) showed apoptotic morphology, 97% of Ccscrape-loaded cells were pyknotic. Moreover, bystander killing extended to neighboring cells, not labeled with RD, and was reduced significantly by the gap junction inhibitors octanol and carbenoxolone. We hypothesize that dying cells in the retina generate a gap junction-permeant apoptotic signal that mediates bystander killing. This novel finding of naturally occurring bystander cell death may have important implications in the histogenesis and pathology of the nervous system.
CaV1.3 Channels Are Essential for Development and Presynaptic Activity of Cochlear Inner Hair Cells
Authors: Brandt Andreas , Striessnig Joerg , Moser Tobias 
Published: April 2018

Cochlear inner hair cells (IHCs) release neurotransmitter onto afferent auditory nerve fibers in response to sound stimulation. During early development, afferent synaptic transmission is triggered by spontaneous Ca2+spikes of IHCs, which are under efferent cholinergic control. Around the onset of hearing, large-conductance Ca2+-activated K+channels are acquired, and Ca2+spikes as well as the cholinergic innervation are lost.Here, we performed patch-clamp measurements in IHCs of mice lacking the CaV1.3 channel (CaV1.3-/-) to investigate the role of this prevailing voltage-gated Ca2+channel in IHC development and synaptic function. The small Ca2+current remaining in IHCs from 3-week-old CaV1.3-/-mice was mainly mediated by L-type Ca2+channels, because it was sensitive to dihydropyridines but resistant to inhibitors of non-L-type Ca2+channels such as ω-conotoxins GVIA and MVIIC and SNX-482. Depolarization induced only marginal exocytosis in CaV1.3-/-IHC, which was solely mediated by L-type Ca2+channels, whereas robust exocytic responses were elicited by photolysis of caged Ca2+. Secretion triggered by short depolarizations was reduced proportionally to the Ca2+current, suggesting that the coupling of the remaining channels to exocytosis was unchanged.CaV1.3-/-IHCs lacked the Ca2+action potentials and displayed a complex developmental failure. Most strikingly, we observed a continued presence of efferent cholinergic synaptic transmission and a lack of functional large-conductance Ca2+-activated K+channels up to 4 weeks after birth. We conclude that CaV1.3 channels are essential for normal hair cell development and synaptic transmission.
Pathway-Specific Action of γ-Hydroxybutyric Acid in Sensory Thalamus and Its Relevance to Absence Seizures
Authors: Gervasi Nicolas , Monnier Zohreh , Vincent Pierre , Paupardin-Tritsch Danièle , Hughes Stuart W. , Crunelli Vincenzo , Leresche Nathalie 
Published: April 2018

The systemic injection of γ-hydroxybutyric acid (GHB) elicits spike and wave discharges (SWDs), the EEG hallmark of absence seizures, and represents a well established, widely used pharmacological model of this nonconvulsive epilepsy. Despite this experimental use of GHB, as well as its therapeutic use in narcolepsy and its increasing abuse, however, the precise cellular mechanisms underlying the different pharmacological actions of this drug are still unclear.Because sensory thalamic nuclei play a key role in the generation of SWDs and sleep rhythms, and because direct injection of GHB in the ventrobasal (VB) thalamus elicits SWDs, we investigated GHB effects on corticothalamic EPSCs and GABAergic IPSCs in VB thalamocortical (TC) neurons. GHB (250 μm-10 mm) reversibly decreased the amplitude of electrically evoked EPSCs and GABAAIPSCs via activation of GABABreceptors; however, ∼60% of the IPSCs were insensitive to low (250 μm-1.0 mm) GHB concentrations. The putative GHB receptor antagonist NSC 382 applied alone had a number of unspecific effects, whereas it either had no action on, or further increased, the GHB-elicited effects on synaptic currents. Low GHB concentrations (250 μm) were also effective in increasing absence-like intrathalamic oscillations evoked by cortical afferent stimulation.These results indicate that low concentrations of GHB, similar to the brain concentrations that evoke SWDsin vivo, differentially affect excitatory and inhibitory synaptic currents in TC neurons and promote absence-like intrathalamic oscillations. Furthermore, the present data strengthen previous suggestions on the GHB mechanism of sleep promotion and will help focus future studies on the cellular mechanisms underlying its abuse.
The Atypical Rho GTPase CHW-1 Works with SAX-3/Robo To Mediate Axon Guidance inCaenorhabditis elegans
Authors: Alan Jamie K , Robinson Sara K , Magsig Katie L , Demarco Rafael S , Lundquist Erik A 
Published: April 2018

AbstractDuring development, neuronal cells extend an axon toward their target destination in response to a cue to form a properly functioning nervous system. Rho proteins, Ras-related small GTPases that regulate cytoskeletal organization and dynamics, cell adhesion, and motility, are known to regulate axon guidance. Despite extensive knowledge about canonical Rho proteins (RhoA/Rac1/Cdc42), little is known about the Caenorhabditis elegans (C. elegans) atypical Cdc42-like family members CHW-1 and CRP-1 in regards to axon pathfinding and neuronal migration. chw-1(Chp/Wrch) encodes a protein that resembles human Chp (Wrch-2/RhoV) and Wrch-1 (RhoU), and crp-1 encodes for a protein that resembles TC10 and TCL. Here, we show that chw-1 works redundantly with crp-1 and cdc-42 in axon guidance. Furthermore, proper levels of chw-1 expression and activity are required for proper axon guidance. When examining CHW-1 GTPase mutants, we found that the native CHW-1 protein is likely partially activated, and mutations at a conserved residue (position 12 using Ras numbering, position 18 in CHW-1) alter axon guidance and neural migration. Additionally, we showed that chw-1 genetically interacts with the guidance receptor sax-3 in PDE neurons. Finally, in VD/DD motor neurons, chw-1 works downstream of sax-3 to control axon guidance. In summary, this is the first study implicating the atypical Rho GTPases chw-1 and crp-1 in axon guidance. Furthermore, this is the first evidence of genetic interaction between chw-1 and the guidance receptor sax-3. These data suggest that chw-1 is likely acting downstream and/or in parallel to sax-3 in axon guidance.