Types Of Transmitters Research Articles

Surgical procedure for implanting a radiotelemetry transmitter to monitor ECG, heart rate and body temperature in small Carassius auratus and Carassius auratus gibelio under laboratory conditions

Radiotelemetry provides an alternative means of obtaining physiological measurements from conscious and freely moving animals, without introducing stress artefacts. A surgical procedure is described for implanting radiotelemetry transmitters to monitor the electrocardiogram (ECG), heart rate (HR) and body temperature (BT) in small goldfish (Carassius auratus; 50-100 g) and Prussian carp (Carassius auratus gibelio; 100 g). This type of transmitter is commonly implanted in freely moving mice. After surgery and a recovery period of 24 h, the ECG, HR and BT were recorded in freely swimming fish within the limitations of the aquarium.

Comparison of Two External Transmitter Types on Two Sizes of Bluegills and Yellow Perch

AbstractWe compared two external transmitter styles on two size‐classes of bluegills Lepomis macrochirus (laterally compressed) and yellow perch Perca flavescens (fusiform) to determine the effects of (1) even distribution of transmitter weight and (2) transmitter weights above and below the recommended 2% of fish body weight. Fish were collected, acclimated for 3 weeks before transmitter attachment, measured for length and weight, Floy tagged, and randomly assigned to treatments (single‐sided transmitter, saddle transmitter, and control). Weight and length of individual fish were recorded every 5 d through day 20 and every 10 d through day 40. On day 40, we classified tag migration, wound redness, and organosomatic indices. Saddle transmitters required the longest handling time of all treatments and did not outperform single‐sided transmitters. On day 40, only small yellow perch had gained more weight with saddle transmitters than with single‐sided transmitters. Transmitters that exceeded 2% of fish weight slowed bluegill growth, whereas transmitters that were less than 2% of fish weight negatively affected yellow perch growth. Our results suggest that even the distribution of external transmitter weight may be less important than the method of attachment and transmitter weight. Development of improved attachment methods for saddle transmitters may prove beneficial for use in long‐term studies of small, fusiform fish.

Near Simultaneous Release of Classical and Peptide Cotransmitters from Chromaffin Cells

Adrenal chromaffin cells are an important part of the neuroendocrine system and under stressful conditions release catecholamines into the blood, thus regulating many physiological processes. In addition to the catecholamines, chromaffin cells also synthesize a range of peptides, including neuropeptide Y. Although the catecholamines and peptides are both contained within dense core granules, whether they are copackaged is less clear. Here, I investigate whether a single dense core granule can be loaded with both types of transmitter molecules. Using amperometry and FMRFamide tagging, I simultaneously measure the secretion of the catecholamines and a neuropeptide from mouse chromaffin cells in vitro. I find that fusion of a single dense core granule releases both types of transmitters into the extracellular space. Significant amounts of peptide escape from a fusing granule in 1-2 ms: almost as rapidly as the catecholamines. This suggests that the kinetics of peptide secretion might not be as sluggish as sometimes thought.

Study on the general principle of normal circular-arc gear transmission

As a typical engineering application of basic principle of Bertrand conjugate surfaces, the general principle of normal circular-arc gear transmission, including paralleled-axis, intersected-axis and crossed-axis, is systematically studied. The research method, from datum surface to the directrix, is presented. The types of datum surfaces and the directrixes of all kinds of transmissions and the method to generate tooth flank of normal circular-arc gear are developed, and the investigation on the noninterference condition is performed by the curvature axis. Three typical normal circular-arc gear transmissions as loxodromic-type, geodesic-type and hyperboloidal-type under the condition of intersected-axis and crossed-axis are proposed.

Carl Nielsen and the Radio

On 1 April 1925 Denmark introduced national control of its hitherto privately run and relatively chaotic radio broadcasting. Denmark would quickly show itself to be one of Europe’s leading nations with regard to both the number of licence-paying listeners and the role of serious music in broadcasting policy. This situation was also reflected very directly in the case of Carl Nielsen. Out of the total of 5,802 performances of his work which the article’s author has been able to document until Nielsen’s death in 1931, 922 (or nearly a sixth) were either produced directly for radio (where in general all music was broadcast live), or broadcast via Danish and foreign radio. Nielsen’s attitude to the new medium was ambivalent from the beginning and gradually cooled. Indeed, the head of the Danish State Radio, kammersanger Emil Holm, was one of his friends, and Nielsen readily accepted when he was asked to conduct his own works at the concerts, which marked milestones in the newly founded Radio Orchestra’s development. He was also a member of the committee that decided in 1926 which type of transmitter the new radio station in Kalundborg would use. But he composed only a few, not especially important new works for radio use, and does not seem to have been clear about what the radio medium meant for his music at a European level. The article presents a series of hitherto unknown documents concerning Carl Nielsen’s relationship to the radio medium, and includes a schematic chart in the appendix offering a detailed overview of which Nielsen works a listener could have heard, and when, on Danish and foreign radio stations up until the composer’s death.

Fast neurotransmission in the rat medial preoptic nucleus

The functional properties of neurotransmission in the medial preoptic nucleus (MPN) were studied in a brain slice preparation from young male rats. The aims were to evaluate the thin slice preparation for studying evoked synaptic responses in MPN neurons, to characterize the fast responses triggered by activation of presynaptic nerve fibers in the MPN, and to identify the involved receptor types. Presynaptic stimulation within the MPN evoked postsynaptic voltage and current responses that were blocked by 200 μM Cd 2+ or by 2.0 μM tetrodotoxin and were attributed to action potential-evoked transmitter release. The relation to stimulus strength and comparison with spontaneous synaptic currents suggested that in many cases only one presynaptic nerve fiber was excited by the stimulus. Furthermore, the transmission was probabilistic in nature, with frequent failures. Thus, response probability, most likely reflecting transmitter release probability, could be evaluated in the thin slice preparation. Evoked excitatory postsynaptic currents recorded under voltage-clamp conditions were, due to kinetics, I– V relation, and pharmacological properties, attributed to AMPA/kainate receptors and NMDA receptors, whereas inhibitory currents were attributed to GABA A receptors. No responses that could be attributed to glycine or other types of primary transmitters were detected. Although serotonin (5-HT) did not appear to function as a primary transmitter, glutamate- as well as GABA-mediated transmission was suppressed by 500 μM 5-HT, with a clear reduction in response probability observed. 5-HT also reduced the frequency, but not the amplitude, of spontaneous postsynaptic currents and was therefore ascribed a presynaptic site of action.

A cochlear implant user's guide to assistive devices and telephones

A cochlear implant user's guide to assistive devices and telephones

Dispersion and radial depth of investigation of borehole modes

ABSTRACTSonic techniques in geophysical prospecting involve elastic wave velocity measurements that are performed by placing acoustic transmitters and receivers in a fluid‐filled borehole. The signals recorded at the receivers are processed to obtain compressional‐ and shear‐wave velocities in the surrounding formation. These velocities are generally used in seismic surveys for the time‐to‐depth conversion and other formation parameters, such as porosity and lithology. Depending upon the type of transmitter used (e.g. monopole or dipole) and as a result of eccentering, it is possible to excite axisymmetric (n= 0), flexural (n= 1) and quadrupole (n= 2) families of modes propagating along the borehole. We present a study of various propagating and leaky modes that includes their dispersion and attenuation characteristics caused by radiation into the surrounding formation. A knowledge of propagation characteristics of borehole modes helps in a proper selection of transmitter bandwidth for suppressing unwanted modes that create problems in the inversion for the compressional‐ and shear‐wave velocities from the dispersive arrivals. It also helps in the design of a transmitter for a preferential excitation of a given mode in order to reduce interference with drill‐collar or drilling noise for sonic measurements‐while‐drilling. Computational results for the axisymmetric family of modes in a fast formation with a shear‐wave velocity of 2032 m/s show the existence of Stoneley, pseudo‐Rayleigh and anharmonic cut‐off modes. In a slow formation with a shear‐wave velocity of 508 m/s, we find the existence of the Stoneley mode and the first leaky compressional mode which cuts in at approximately the same normalized frequency ωa/VS= 2.5 (a is the borehole radius) as that of the fast formation. The corresponding modes among the flexural family include the lowest‐order flexural and anharmonic cut‐off modes. For both the fast and slow formations, the first anharmonic mode cuts in at a normalized frequency ωa/VS= 1.5 approximately. Cut‐off frequencies of anharmonic modes are inversely proportional to the borehole radius in the absence of any tool. The borehole quadrupole mode can also be used for estimating formation shear slownesses. The radial depth of investigation with a quadrupole mode is marginally less than that of a flexural mode because of its higher frequency of excitation.

ANESTHÉSIE ET PROCÉDURES CHIRURGICALES POUR L’IMPLANTATION DE RADIO ÉMETTEURS DANS LA CAVITÉ VENTRALE DE TRUITES COMMUNES ADULTES (SALMO TRUTTA)

The aim of this study was to determine the best intraperitoneal surgical tagging technique for brown trout (Salmo trutta) by radiotransmitter. Two types of anaesthesia, using either clove oil or electricity were compared. Two types of transmitters, with external trailing antenna or internal coil antenna, and two incision zones, anterior and posterior to the pelvic girdle, were tested.

Genetic Analysis of the Roles of Hh, FGF8, and Nodal Signaling during Catecholaminergic System Development in the Zebrafish Brain

CNS catecholaminergic neurons can be distinguished by their neurotransmitters as dopaminergic or noradrenergic and form in distinct regions at characteristic embryonic stages. This raises the question of whether all catecholaminergic neurons of one transmitter type are specified by the same set of factors. Therefore, we performed genetic analyses to define signaling requirements for the specification of distinct clusters of catecholaminergic neurons in zebrafish. In mutants affecting midbrain- hindbrain boundary (MHB) organizer formation, the earliest ventral diencephalic dopaminergic neurons appear normal. However, after 2 d of development, we observed fewer cells than in wild types, which suggests that the MHB provides proliferation or survival factors rather than specifying ventral diencephalic dopaminergic clusters. In hedgehog (Hh) pathway mutants, the formation of catecholaminergic neurons is affected only in the pretectal cluster. Surprisingly, neither fibroblast growth factor 8 (FGF8) alone nor in combination with Hh signaling is required for specification of early developing dopaminergic neurons. We analyzed the formation of prosomeric territories in the forebrain of Hh and Nodal pathway mutants to determine whether the absence of specific dopaminergic clusters may be caused by early patterning defects ablating corresponding parts of the CNS. In Nodal pathway mutants, ventral diencephalic and pretectal catecholaminergic neurons fail to develop, whereas both anatomical structures form at least in part. This suggests that Nodal signaling is required for catecholaminergic neuron specification. In summary, our results do not support the previously suggested dominant roles for sonic hedgehog and Fgf8 in specification of the first catecholaminergic neurons, but instead indicate a novel role for Nodal signaling in this process.

Daily survival rates of ruffed grouseBonasa umbellusin northern Minnesota

We radio-marked 56 ruffed grouse Bonasa umbellus in northern Minnesota, USA, during 1963–1965 and 2001–2002. Of these, we estimated the daily survival rate of 49 individuals (32 females and 17 males; of which 27 were grey phase and 22 were red phase) during the breeding and non-breeding seasons. We investigated whether daily survival varied by age, colour phase, gender, season and transmitter type. A model representing an interaction between colour phase and season fit the data best (AICc = 154.760) and was 77% more likely than any of our other a priori models. Daily survival rates were identical during the breeding season (0.998; SE = 0.002 for both colour phases), but higher for red-phased (0.994; SE = 0.003) than for grey-phased (0.980; SE = 0.007) birds during the non-breeding season. The daily estimate of grouse survival pooled across all individuals and seasons was 0.994 (SE = 0.002), which yielded an annual survival probability of 0.111 (SE = 0.082). The estimated annual survival rate was 0.010 (SE = 0.132) for grey-phased birds and 0.206 (SE = 0.146) for red-phased birds. There was no difference in survival rates between the two study periods. Our estimated annual survival rates were similar to other rates reported for ruffed grouse.

Modélisation en régime transitoire des mouvements convectifs dans une cellule d'habitation

This study aims thermal phenomena modelling inside a dwelling cell in order to determine temperature distribution there. A coupling of the zonal method and integral analysis in walls vicinity is carried out. The zonal method lies on breaking up the cell into isothermal zones. Mass and energy balances are established, in transient flow, for each zone. The various convective transfer types are listed and studied: transfer between air and walls, transfer between air layers, transfer between air and cold air jet, transfer between air and transmitter. Conductive transfer through walls and radiative transfer inside the cell are also taken into account. An experimental validation campaign is also achieved in a testing room, two heat transmitter types are tested: distributed and located. Validation results are satisfying and air diffusion importance is emphasised. The influence of air nodes number is also studied.

Selective Effects of Insecticides on Nigrostriatal Dopaminergic Nerve Pathways

A degeneration of the nigrostriatal pathway is a primary component of Parkinson’s disease (PD), and we have investigated the actions of insecticides on this pathway. For in vivo exposures, C57BL/6 mice were treated three times over a 2-week period with heptachlor, the pyrethroids deltamethrin and permethrin, or chlorpyrifos. One day after the last treatment, we observed that heptachlor and the pyrethroids increased maximal [ 3H ]dopamine uptake in striatal synaptosomes from treated mice, with dose-dependent changes in V max displaying a bell-shaped curve. Western blot analysis confirmed increased levels of dopamine transporter (DAT) protein in the striatum of mice treated with heptachlor and permethrin. In contrast, we observed a small, but statistically significant decrease in dopamine uptake by 100 mg/kg chlorpyrifos. For heptachlor, doses that upregulated DAT expression had little or no effect on serotonin transport. Permethrin did cause an upregulation of serotonin transport, but required a 30-fold greater dose than that effective on dopamine uptake. Other evidence of specificity was found in transmitter release assays, where heptachlor and deltamethrin released dopamine from striatal terminals with greater potency than other transmitter types. These findings confirm that insecticides possess specificity for effects on striatal dopaminergic neurotransmission.

A biochemical approach to study sub-second endogenous release of diverse neurotransmitters from central nerve terminals

Exocytosis in central nerve terminals is rapidly triggered by the influx of calcium through high voltage sensitive Ca 2+-channels. Mainly due to their small size, studies in which neurotransmitter release from these terminals was determined at the sub-second time-scale are still rather limited. Here we describe the use of a pneumatic rapid mixing device, allowing application of short (≥50 ms) K +-depolarizing pulses to purified nerve terminals, synaptosomes, to trigger endogenous release of different transmitter types. A consistent, Ca 2+-dependent exocytotic release of the amino acid transmitters, glutamate and GABA, from synaptosomes purified from rat and mouse brain was observed after 100 ms depolarization. For determination of amino acid release after longer depolarizations (>100 ms), transporter blockers had to be added to prevent clearance of the vesicularly released transmitters. Ca 2+-dependent release of the neuropeptide cholecystokinin occured only after 250 ms depolarization. In addition, the time-courses of amino acid and cholecystokinin release were clearly different. The fast Ca 2+-dependent release of all transmitters was selectively and strongly inhibited by the P/Q-type Ca 2+-channel blocker ω-Agatoxin IVA. In conclusion, this approach allows direct measurement of Ca 2+-dependent release of diverse endogenous neurotransmitters from central nerve terminals upon depolarization pulses at a physiologically relevant, sub-second, time scale.

Induction of a dopaminergic phenotype in cultured striatal neurons by bone morphogenetic proteins

In the present study, we examined whether the bone morphogenetic proteins (BMPs), which are important in the developmental specification of transmitter type in certain classes of neurons, might also play a role in signaling the differentiation of a dopaminergic (DA) phenotype. We found that BMP-2, -4 and -6 were each capable of inducing, in a dose and time dependent manner, moderate levels of the DA enzyme tyrosine hydroxylase (TH) in cultured neurons from the mouse embryonic striatum. In contradistinction to other TH-inducing agents, BMPs initiated de novo TH expression without the required synergy of exogenous growth factors or co-activating substances and in neurons presumably aged (E16) beyond the critical period for induction. However, the appearance of TH in induced cells was short-lived (24 h) and could not be prolonged by repeated supplementation with the BMPs. Inhibitors of the mitogen-activated protein kinase (MAPK/ERK) signaling pathway, PD98059 and apigenin, did not prevent TH induction by BMP-4, as they did other TH inducing agents, indicating that the MAPK/ERK pathway does not mediate BMPs effects on TH expression. We conclude that BMP-2, -4 and -6 can be added to the expanding inventory of agents capable of inducing TH, making them potentially important in the specification of a DA phenotype in stem/precursor cells for the treatment of Parkinson’s disease.

Thin film optical waveguide type UV sensor using a photochromic molecular device, spirooxazine

New waveguide type UV sensor using photochromic dye as a molecular light transducer has been studied. When exposed to UV radiation, thin film UV sensing membrane that is composed of spirooxazine derivative and polymer matrix (PMMA, poly(methyl methacrylate)) shows remarkable light absorption in the visible range ( λ max =587 nm ) reversibly from the original characteristics of spirooxazine dye. Since this polymeric thin film can also act as an intrinsic waveguide, it is useful to construct planar waveguide type sensor. The output intensity of inputted and guided visible light ( λ=633 nm , He–Ne laser) through planar thin film waveguide was decreased according to the amount of photochromic dye absorbance by the UV photon energy in the optical path. The sensitivity of waveguide type UV sensor was 64 times greater than that of a traditional transmittance type polymer membrane.

Demonstration of negative dispersion fibers for DWDM metropolitan area networks

We present a detailed experimental and theoretical study, showing that a novel nonzero dispersion-shifted fiber with negative dispersion enhances the capabilities of metropolitan area optical systems, while at the same time, reducing the system cost by eliminating the need of dispersion compensation. The performance of this dispersion-optimized fiber was studied using different types of optical transmitters for both 1310- and 1550-nm wavelength windows and for both 2.5-and 10-Gb/s bit rates. It is shown that this new fiber extends the nonregenerated distance up to 300 km when directly modulated distributed feedback (DFB) laser transmitters at 2.5 Gb/s are used. The negative dispersion characteristics of the fiber also enhance the transmission performance in metropolitan area networks with transmitters that use electroabsorption (EA) modulator integrated distributed feedback (DFB) lasers, which are biased for positive chirp. In the case of 10 Gb/s, externally modulated signals (using either EA-DFBs or external modulated lasers using Mach-Zehnder modulators), we predict that the maximum reach that can be accomplished without dispersion compensation is more than 200 km for both 100- and 200-GHz channel spacing. To our knowledge, this is the first demonstration of the capabilities of a nonzero dispersion-shifted fiber with negative dispersion for metropolitan applications.

Multiple oscillators, dynamic synchronization and sympathetic control.

1. Intermittent bursts of activity are a robust feature of the discharges of sympathetic nerves. There are at least two major mechanisms producing such discharges: (i) phasic inputs influencing sympathetic circuits; and (ii) oscillators embedded within sympathetic networks. The functional significance of patterned and synchronized activity underlying bursts of population activity may reside in their influence on information transfer between excitable cells. At the level of the single neuron, firing pattern appears to be an important determinant of synaptic/neuroeffector function (e.g. the probability of transmitter release, the types of transmitter released, the types of receptor activated and plasticity). Synchronization of inputs at a target favours summation and, therefore, may influence response (short term and long term). 2. In the present paper, I review the work from my laboratory that has focused on furthering understanding of the potential functional importance of pattern and synchrony coding in sympathetic nervous control of cardiovascular function. Because the rat tail artery has been used extensively as a model for studying neuroeffector transmission, in our investigations we have recorded from its sympathetic innervation. 3. In the anaesthetized preparation, under steady state conditions, we have established that the discharges of these sympathetic neurons have a distinct rhythm (frequency approximately 0.8 Hz). This can be detected both at single neuron and population levels. 4. A family of oscillators appears to control their discharge such that under some conditions all neurons do not have the same frequency of rhythmical activity. However, these weakly coupled or uncoupled oscillators can be synchronized dynamically by various inputs, such as central respiratory drive, lung inflation cycle-related inputs and inputs arising from visceral and somatic afferents. 5. The potential functional significance of dynamic synchronization of sympathetic oscillators in relation to sympathetic pattern generation and neuroeffector transmission is discussed.

Modulation of acetylcholine release from mouse cortex by protein kinase C: Dependence on stimulation intensity

Activation of protein kinase C (PKC) results in enhanced action-potential evoked release of a variety of transmitters. However, previous studies have suggested that acetylcholine release is poorly modulated by PKC compared to other transmitter types. We investigated the effect of stimulation conditions on PKC modulation of electrical stimulation-induced acetylcholine release in mouse cortex, which were incubated with [ 3H]choline. The PKC activator phorbol dibutyrate (PDB) enhanced acetylcholine release at low stimulation frequencies (0.1 and 0.5Hz) and not at 3 or 10Hz. At 3Hz stimulation, when release was inhibited by neostigmine, PDB enhanced acetylcholine release, suggesting that at low levels of acetylcholine release, exogenous activation of PKC can elevate acetylcholine release. However, at higher frequencies, PKC may already be endogenously activated since the PKC inhibitor polymyxin B (PXB) inhibited acetylcholine release. The other PKC inhibitors, Ro 318220, Gö 6976, bisindolylmaleimide and calphostin C appeared to have no effect at 3Hz. It may be that these inhibitors do not effectively block PKC in this functional system. Indeed, polymyxin B completely blocked the facilitatory effect of PDB but Ro 318220 was without effect.

Ultrastructural organization of transmitters in the cat lateralis medialis-suprageniculate nucleus of the thalamus: an immunohistochemical study.

The lateralis medialis-suprageniculate nuclear (LM-Sg) complex of the cat's posterior thalamus receives a rather wide variety of inputs from diverse cortical and subcortical areas. Previous ultrastructural studies of this nucleus demonstrated the presence of four types of vesicle-containing profiles and characterized some of these as gamma-aminobutyric acid (GABA)-containing terminals (Norita and Katoh [1987] J. Comp. Neurol. 263:54-67; Norita and Katoh [1988] Prog. Brain Res. 75:109-118). The present study has extended these observations by examining the immunoreactivity (ir) of LM-Sg, with antibodies raised against aspartate (Asp), glutamate (Glu), GABA, the acetylcholine (ACh) marker, choline acetyltransferase (ChAT), and substance P (SP), by using light and electron microscopy. Neuronal somata immunopositive for the excitatory amino acids (EAAs) Asp and Glu, were of medium size. EAA-ir terminals also were of medium size and contained round synaptic vesicles; they made asymmetrical synaptic contacts with dendritic profiles. Neuronal somata immunopositive for GABA were small. GABA-positive terminals also were small and contained pleomorphic synaptic vesicles; they formed symmetrical synaptic contacts with dendritic profiles. No neurons immunolabeled for ChAT were found. Terminals immunopositive for ChAT were small and contained round synaptic vesicles; these made symmetrical synaptic contacts, asymmetrical synaptic contacts, or both, of the en passant type with dendritic profiles. SP-immunolabeled neuronal somata were not found. Immunolabeled terminals were small, contained round synaptic vesicles, and made asymmetrical synaptic contacts with dendritic profiles. ChAT-ir and SP-ir axon terminals were not expressed evenly within LM-Sg. This difference in distribution suggests that within the LM-Sg, there may be a difference in specific sensory processing functions which correlate with transmitter type.