Pancreatic Beta Cells Synthesize Neuropeptide Y and Can Rapidly Release Peptide Co-Transmitters

PubMed Central

Whim, Matthew D.

2011-01-01

Background In addition to polypeptide hormones, pancreatic endocrine cells synthesize a variety of bioactive molecules including classical transmitters and neuropeptides. While these co-transmitters are thought to play a role in regulating hormone release little is known about how their secretion is regulated. Here I investigate the synthesis and release of neuropeptide Y from pancreatic beta cells. Methodology/Principal Findings NPY appears to be an authentic co-transmitter in neonatal, but not adult, beta cells because (1) early in mouse post-natal development, many beta cells are NPY-immunoreactive whereas no staining is observed in beta cells from NPY knockout mice; (2) GFP-expressing islet cells from an NPY(GFP) transgenic mouse are insulin-ir; (3) single cell RT-PCR experiments confirm that the NPY(GFP) cells contain insulin mRNA, a marker of beta cells. The NPY-immunoreactivity previously reported in alpha and delta cells is therefore likely to be due to the presence of NPY-related peptides. INS-1 cells, a beta cell line, are also NPY-ir and contain NPY mRNA. Using the FMRFamide tagging technique, NPY secretion was monitored from INS-1 beta cells with high temporal resolution. Peptide release was evoked by brief depolarizations and was potentiated by activators of adenylate cyclase and protein kinase A. Following a transient depolarization, NPY-containing dense core granules fused with the cell membrane and discharged their contents within a few milliseconds. Conclusions These results indicate that after birth, NPY expression in pancreatic islets is restricted to neonatal beta cells. The presence of NPY suggests that peptide co-transmitters could mediate rapid paracrine or autocrine signaling within the endocrine pancreas. The FMRFamide tagging technique may be useful in studying the release of other putative islet co-transmitters in real time. PMID:21559341

Readily releasable pool of synaptic vesicles measured at single synaptic contacts.

PubMed

Trigo, Federico F; Sakaba, Takeshi; Ogden, David; Marty, Alain

2012-10-30

To distinguish between different models of vesicular release in brain synapses, it is necessary to know the number of vesicles of transmitter that can be released immediately at individual synapses by a high-calcium stimulus, the readily releasable pool (RRP). We used direct stimulation by calcium uncaging at identified, single-site inhibitory synapses to investigate the statistics of vesicular release and the size of the RRP. Vesicular release, detected as quantal responses in the postsynaptic neuron, showed an unexpected stochastic variation in the number of quanta from stimulus to stimulus at high intracellular calcium, with a mean of 1.9 per stimulus and a maximum of three or four. The results provide direct measurement of the RRP at single synaptic sites. They are consistent with models in which release proceeds from a small number of vesicle docking sites with an average occupancy around 0.7.

Stretch-induced Ca2+ independent ATP release in hippocampal astrocytes.

PubMed

Xiong, Yingfei; Teng, Sasa; Zheng, Lianghong; Sun, Suhua; Li, Jie; Guo, Ning; Li, Mingli; Wang, Li; Zhu, Feipeng; Wang, Changhe; Rao, Zhiren; Zhou, Zhuan

2018-02-28

Similar to neurons, astrocytes actively participate in synaptic transmission via releasing gliotransmitters. The Ca 2+ -dependent release of gliotransmitters includes glutamate and ATP. Following an 'on-cell-like' mechanical stimulus to a single astrocyte, Ca 2+ independent single, large, non-quantal, ATP release occurs. Astrocytic ATP release is inhibited by either selective antagonist treatment or genetic knockdown of P2X7 receptor channels. Our work suggests that ATP can be released from astrocytes via two independent pathways in hippocampal astrocytes; in addition to the known Ca 2+ -dependent vesicular release, larger non-quantal ATP release depends on P2X7 channels following mechanical stretch. Astrocytic ATP release is essential for brain functions such as synaptic long-term potentiation for learning and memory. However, whether and how ATP is released via exocytosis remains hotly debated. All previous studies of non-vesicular ATP release have used indirect assays. By contrast, two recent studies report vesicular ATP release using more direct assays. In the present study, using patch clamped 'ATP-sniffer cells', we re-investigated astrocytic ATP release at single-vesicle resolution in hippocampal astrocytes. Following an 'on-cell-like' mechanical stimulus of a single astrocyte, a Ca 2+ independent single large non-quantal ATP release occurred, in contrast to the Ca 2+ -dependent multiple small quantal ATP release in a chromaffin cell. The mechanical stimulation-induced ATP release from an astrocyte was inhibited by either exposure to a selective antagonist or genetic knockdown of P2X7 receptor channels. Functional P2X7 channels were expressed in astrocytes in hippocampal brain slices. Thus, in addition to small quantal ATP release, larger non-quantal ATP release depends on P2X7 channels in astrocytes. © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.

Role of glycogenolysis in stimulation of ATP release from cultured mouse astrocytes by transmitters and high K+ concentrations.

PubMed

Xu, Junnan; Song, Dan; Bai, Qiufang; Zhou, Lijun; Cai, Liping; Hertz, Leif; Peng, Liang

2014-01-13

This study investigates the role of glycogenolysis in stimulated release of ATP as a transmitter from astrocytes. Within the last 20 years our understanding of brain glycogenolysis has changed from it being a relatively uninteresting process to being a driving force for essential brain functions like production of transmitter glutamate and homoeostasis of potassium ions (K+) after their release from excited neurons. Simultaneously, the importance of astrocytic handling of adenosine, its phosphorylation to ATP and release of some astrocytic ATP, located in vesicles, as an important transmitter has also become to be realized. Among the procedures stimulating Ca2+-dependent release of vesicular ATP are exposure to such transmitters as glutamate and adenosine, which raise intra-astrocytic Ca2+ concentration, or increase of extracellular K+ to a depolarizing level that opens astrocytic L-channels for Ca2+ and thereby also increase intra-astrocytic Ca2+ concentration, a prerequisite for glycogenolysis. The present study has confirmed and quantitated stimulated ATP release from well differentiated astrocyte cultures by glutamate, adenosine or elevated extracellular K+ concentrations, measured by a luciferin/luciferase reaction. It has also shown that this release is virtually abolished by an inhibitor of glycogenolysis as well as by inhibitors of transmitter-mediated signaling or of L-channel opening by elevated K+ concentrations.

Cellular Distribution and Subcellular Localization of Molecular Components of Vesicular Transmitter Release in Horizontal Cells of Rabbit Retina

PubMed Central

HIRANO, ARLENE A.; BRANDSTÄTTER, JOHANN H.; BRECHA, NICHOLAS C.

2010-01-01

The mechanism underlying transmitter release from retinal horizontal cells is poorly understood. We investigated the possibility of vesicular transmitter release from mammalian horizontal cells by examining the expression of synaptic proteins that participate in vesicular transmitter release at chemical synapses. Using immunocytochemistry, we evaluated the cellular and subcellular distribution of complexin I/II, syntaxin-1, and synapsin I in rabbit retina. Strong labeling for complexin I/II, proteins that regulate a late step in vesicular transmitter release, was found in both synaptic layers of the retina, and in somata of A- and B-type horizontal cells, of γ-aminobutyric acid (GABA)- and glycinergic amacrine cells, and of ganglion cells. Immunoelectron microscopy demonstrated the presence of complexin I/II in horizontal cell processes postsynaptic to rod and cone ribbon synapses. Syntaxin-1, a core protein of the soluble N-ethylmaleimide-sensitive-factor attachment protein receptor (SNARE) complex known to bind to complexin, and synapsin I, a synaptic vesicle-associated protein involved in the Ca2+-dependent recruitment of synaptic vesicles for transmitter release, were also present in the horizontal cells and their processes at photoreceptor synapses. Photoreceptors and bipolar cells did not express any of these proteins at their axon terminals. The presence of complexin I/II, syntaxin-1, and synapsin I in rabbit horizontal cell processes and tips suggests that a vesicular mechanism may underlie transmitter release from mammalian horizontal cells. PMID:15912504

Desensitization shortens the high-quantal-content endplate current time course in frog muscle with intact cholinesterase.

PubMed

Giniatullin, R A; Talantova, M; Vyskocil, F

1997-08-01

1. The desensitization induced by bath-applied carbachol or acetylcholine (ACh) and potentiated by proadifen (SKF 525A) was studied in the frog sartorius with intact synaptic acetylcholinesterase (AChE). 2. The reduction in the density and number of postsynaptic receptors produced by desensitization lowered the amplitude of the endplate currents (EPCs) and shortened the EPC decay when the quantal content (m) of the EPC was about 170 and when multiple release of quanta at single active zones was highly probably. The shortening of high-quantal-content EPCs persisted for at least 15 min after the wash-out of agonists, at a time when the amplitude had recovered fully. 3. The decay times of the low-quantal-content EPCs recorded from preparations pretreated with 5 mM Mg2+ (m approximately 70) and single-quantum miniature endplate currents (MEPCs) were not affected by carbachol, ACh or proadifen. 4. The desensitization of ACh receptors potentiated by proadifen, prevented completely the 6- to 8-fold prolongation of EPC which was induced by neostigmine inhibition of synaptic AChE. 5. It is assumed that high-quantal-content EPCs increase the incidence of multiple quanta release at single active zones and the probability of repetitive binding of ACh molecules which leads to EPC prolongation. The shortening which persists after complete recovery of the amplitude during wash-out of the exogenous agonist is probably due to 'trapping' of ACh molecules onto rapidly desensitized receptors and the reduced density of functional AChRs during the quantum action.

Prostaglandin action on transmitter release of adrenergic neuroeffector junctions.

PubMed

Hedqvist, P

1976-01-01

The results presented here indicate that 1. The inhibitory action of the endoperoxides on NE release can be at least partly explained in terms of formation of degradation products, presumably mainly PGE2. 2. PGA2 is less active and the PG analogue 16,16-dimethyl-PGE2 more active than PGEs on transmitter release from adrenergic nerves. 3. PGF2alpha seems to enhance vascular responses to renal nerve activity solely by a postjunctional action. 4. PG synthesis inhibition augments NE turnover in a number of rat organs, thereby increasing the probability of PGs being involved in the control of adrenergic neurotransmission in vivo. 5. Prolongation of the duration of the impulse and action potential counteracts the effect of PGE on NE release, thereby strengthening the view that PGs operate on NE release from adrenergic nerve terminals by interfering with Ca2+ influx.

Post-release survival and movement of Western Grebes (Aechmophorus occidentalis) implanted with intracoelomic satellite transmitters

USGS Publications Warehouse

Mills, Kyra L.; Gaydos, Joseph K.; Fiorello, Christine V.; Whitmer, Emily; De La Cruz, Susan; Mulcahy, Daniel M.; Vilchis, L. Ignacio; Ziccardi, Michael H.

2016-01-01

The main goal of this study was to gain knowledge on post-release survival and movement of Western Grebes (Aechmophorus occidentalis) using a modified technique for implanting satellite transmitters. This technique had improved post-surgical survival in an earlier study. Nine Western Grebes, implanted with intracoelomic (within the body cavity) satellite transmitters with percutaneous antennae, were released close to their capture site in San Francisco Bay, California, USA. Eight survived at least 25 days (average number of transmittal days was 140.8), while two had transmitters that provided data for greater than 1 year (436 and 454 days). The average cumulative distance recorded for all Western Grebes (n = 9) was 829 km with two round-trip movements documented. One individual Western Grebe traveled a cumulative round-trip distance of 2,144 km in July and November 2011, while another individual traveled a round-trip distance of 1,514 km between 8 and 14 December 2011. This study provides a step forward in testing implantable satellite transmitters in Western Grebes and highlights the need to further improve tracking methods, potentially improving our understanding of their population threats.

An essential role for vesicular glutamate transporter 1 (VGLUT1) in postnatal development and control of quantal size.

PubMed

Wojcik, S M; Rhee, J S; Herzog, E; Sigler, A; Jahn, R; Takamori, S; Brose, N; Rosenmund, C

2004-05-04

Quantal neurotransmitter release at excitatory synapses depends on glutamate import into synaptic vesicles by vesicular glutamate transporters (VGLUTs). Of the three known transporters, VGLUT1 and VGLUT2 are expressed prominently in the adult brain, but during the first two weeks of postnatal development, VGLUT2 expression predominates. Targeted deletion of VGLUT1 in mice causes lethality in the third postnatal week. Glutamatergic neurotransmission is drastically reduced in neurons from VGLUT1-deficient mice, with a specific reduction in quantal size. The remaining activity correlates with the expression of VGLUT2. This reduction in glutamatergic neurotransmission can be rescued and enhanced with overexpression of VGLUT1. These results show that the expression level of VGLUTs determines the amount of glutamate that is loaded into vesicles and released and thereby regulates the efficacy of neurotransmission.

Hypertonicity-induced transmitter release at Drosophila neuromuscular junctions is partly mediated by integrins and cAMP/protein kinase A

NASA Technical Reports Server (NTRS)

Suzuki, Kazuhiro; Grinnell, Alan D.; Kidokoro, Yoshiaki

2002-01-01

The frequency of quantal transmitter release increases upon application of hypertonic solutions. This effect bypasses the Ca(2+) triggering step, but requires the presence of key molecules involved in vesicle fusion, and hence could be a useful tool for dissecting the molecular process of vesicle fusion. We have examined the hypertonicity response at neuromuscular junctions of Drosophila embryos in Ca(2+)-free saline. Relative to wild-type, the response induced by puff application of hypertonic solution was enhanced in a mutant, dunce, in which the cAMP level is elevated, or in wild-type embryos treated with forskolin, an activator of adenylyl cyclase, while protein kinase A (PKA) inhibitors decreased it. The response was also smaller in a mutant, DC0, which lacks the major subunit of PKA. Thus the cAMP/PKA cascade is involved in the hypertonicity response. Peptides containing the sequence Arg-Gly-Asp (RGD), which inhibit binding of integrins to natural ligands, reduced the response, whereas a peptide containing the non-binding sequence Arg-Gly-Glu (RGE) did not. A reduced response persisted in a mutant, myospheroid, which expresses no integrins, and the response in DC0 was unaffected by RGD peptides. These data indicate that there are at lease two components in the hypertonicity response: one that is integrin mediated and involves the cAMP/PKA cascade, and another that is not integrin mediated and does not involve the cAMP/PKA cascade.

Effect of oxygen at high pressure on spontaneous transmitter release.

PubMed

Colton, J S; Colton, C A

1978-11-01

The effect of oxygen at high pressure (OHP) on resting membrane properties (effective membrane resistance (Reff) and membrane potential (Vm)) and the spontaneous release of excitatory transmitter were examined at the lobster neuromuscular junction. Pressurization with 100% oxygen to 150 pounds per square inch gauge pressure (psig) or with nitrogen to 150 psig (7,000 mmHg nitrogen and 135 mmHg oxygen) produced a decrease in Reff associated with a hyperpolarization of Vm. These changes, however, returned to control values within 20--30 min after completion of pressurization. Spontaneous release of excitatory transmitter was shown to increase dramatically in the presence of 100% oxygen at 150 psig. The increase in miniature end-plate potential (MEPP) frequency persisted beyond the transient changes seen with Reff and Vm. This effect was selective to oxygen, as pressurization with nitrogen did not produce an increase in MEPP frequency. No change in average MEPP amplitude was seen with either OHP or pressure alone. An OHP-induced increase in MEPP frequency was also seen at the frog neuromuscular junction. The results indicate that both glutamate-mediated and acetylcholine-mediated synaptic transmission are altered by OHP.

Quantal amplitude and quantal variance of strontium-induced asynchronous EPSCs in rat dentate granule neurons

PubMed Central

Bekkers, John M; Clements, John D

1999-01-01

Excitatory postsynaptic currents (EPSCs) were recorded from granule cells of the dentate gyrus in acute slices of 17- to 21-day-old rats (22-25 °C) using tissue cuts and minimal extracellular stimulation to selectively activate a small number of synaptic contacts.Adding millimolar Sr2+ to the external solution produced asynchronous EPSCs (aEPSCs) lasting for several hundred milliseconds after the stimulus. Minimally stimulated aEPSCs resembled miniature EPSCs (mEPSCs) recorded in the same cell but differed from them in ways expected from the greater range of dendritic filtering experienced by mEPSCs. aEPSCs had the same stimulus threshold as the synchronous EPSCs (sEPSCs) that followed the stimulus with a brief latency. aEPSCs following stimulation of distal inputs had a slower mean rise time than those following stimulation of proximal inputs. These results suggest that aEPSCs arose from the same synapses that generated sEPSCs.Proximally elicited aEPSCs had a mean amplitude of 6.7 ± 2.2 pA (± s.d., n = 23 cells) at -70 mV and an amplitude coefficient of variation of 0.46 ± 0.08.The amplitude distributions of sEPSCs never exhibited distinct peaks.Monte Carlo modelling of the shapes of aEPSC amplitude distributions indicated that our data were best explained by an intrasite model of quantal variance.It is concluded that Sr2+-evoked aEPSCs are uniquantal events arising at synaptic terminals that were recently invaded by an action potential, and so provide direct information about the quantal amplitude and quantal variance at those terminals. The large quantal variance obscures quantization of the amplitudes of evoked sEPSCs at this class of excitatory synapse. PMID:10066937

Presynaptic membrane potential affects transmitter release in an identified neuron in Aplysia by modulating the Ca2+ and K+ currents.

PubMed

Shapiro, E; Castellucci, V F; Kandel, E R

1980-01-01

We have examined the relationships between the modulation of transmitter release and of specific ionic currents by membrane potential in the cholinergic interneuron L10 of the abdominal ganglion of Aplysia californica. The presynaptic cell body was voltage-clamped under various pharmacological conditions and transmitter release from the terminals was assayed simultaneously by recording the synaptic potentials in the postsynaptic cell. When cell L10 was voltage-clamped from a holding potential of -60 mV in the presence of tetrodotoxin, graded transmitter release was evoked by depolarizing command pulses in the membrane voltage range (-35 mV to + 10 mV) in which the Ca(2+) current was also increasing. Depolarizing the holding potential of L10 results in increased transmitter output. Two ionic mechanisms contribute to this form of plasticity. First, depolarization inactivates some K(+) channels so that depolarizing command pulses recruit a smaller K(+) current. In unclamped cells the decreased K(+) conductance causes spike-broadening and increased influx of Ca(2+) during each spike. Second, small depolarizations around resting potential (-55 mV to -35 mV) activate a steady-state Ca(2+) current that also contributes to the modulation of transmitter release, because, even with most presynaptic K(+) currents blocked pharmacologically, depolarizing the holding potential still increases transmitter release. In contrast to the steady-state Ca(2+) current, the transient inward Ca(2+) current evoked by depolarizing clamp steps is relatively unchanged from various holding potentials.

Protein kinase C involvement in the acetylcholine release reduction induced by amyloid-beta(25-35) aggregates on neuromuscular synapses.

PubMed

Tomàs, Marta; Garcia, Neus; Santafé, Manuel M; Lanuza, Maria; Tomàs, Josep

2009-01-01

Using intracellular recording of the diaphragm muscle of adult rats, we have investigated the short-term functional effects of amyloid-beta (Abeta(25-35) peptide aggregates on the modulation of acetylcholine (ACh) release and the involvement of protein kinase C (PKC). The non-aggregated form of this peptide does not change the evoked and spontaneous transmitter release parameters on the neuromuscular synapse. However, the aggregated form of Abeta(25-35) acutely interferes with evoked quantal ACh release (approximately 40% reduction) when synaptic activity in the ex vivo neuromuscular preparation is maintained by low frequency (1 Hz) electrical stimulation. This effect is partially dependent on the activity of PKC that may have a permissive action. The end result of Abeta(25-35) is in opposition to the PKC-dependent maintenance effect on ACh release manifested in active synapses.

PACAP/PAC1R signaling modulates acetylcholine release at neuronal nicotinic synapses

PubMed Central

Pugh, Phyllis C.; Jayakar, Selwyn S.; Margiotta, Joseph F.

2009-01-01

Neuropeptides collaborate with conventional neurotransmitters to regulate synaptic output. Pituitary adenylate cyclase-activating polypeptide (PACAP) co-localizes with acetylcholine in presynaptic nerve terminals, is released by stimulation, and enhances nicotinic acetylcholine receptor- (nAChR-) mediated responses. Such findings implicate PACAP in modulating nicotinic neurotransmission, but relevant synaptic mechanisms have not been explored. We show here that PACAP acts via selective high-affinity G-protein coupled receptors (PAC1Rs) to enhance transmission at nicotinic synapses on parasympathetic ciliary ganglion (CG) neurons by rapidly and persistently increasing the frequency and amplitude of spontaneous, impulse-dependent nicotinic excitatory postsynaptic currents (sEPSCs). Of the canonical adenylate cyclase (AC) and phospholipase-C (PLC) transduction cascades stimulated by PACAP/PAC1R signaling, only AC-generated signals are critical for synaptic modulation since the increases in sEPSC frequency and amplitude were mimicked by 8-Bromo-cAMP, blocked by inhibiting AC or cAMP-dependent protein kinase (PKA), and unaffected by inhibiting PLC. Despite its ability to increase agonist-induced nAChR currents, PACAP failed to influence nAChR-mediated impulse-independent miniature EPSC amplitudes (quantal size). Instead, evoked transmission assays reveal that PACAP/PAC1R signaling increased quantal content, indicating it modulates synaptic function by increasing vesicular ACh release from presynaptic terminals. Lastly, signals generated by the retrograde messenger, nitric oxide- (NO-) are critical for the synaptic modulation since the PACAP-induced increases in spontaneous EPSC frequency, amplitude and quantal content were mimicked by NO donor and absent after inhibiting NO synthase (NOS). These results indicate that PACAP/PAC1R activation recruits AC-dependent signaling that stimulates NOS to increase NO production and control presynaptic transmitter output at neuronal

TOTAL CULTURABLE VIRUS QUANTAL ASSAY

EPA Science Inventory

This chapter describes a quantal method for assaying culturable human enteric viruses from water matrices. The assay differs from the plaque assay described in Chapter 10 (December 1987 Revision) in that it is based upon the direct microscopic viewing of cells for virus-induced ...

Hypertonic enhancement of transmitter release from frog motor nerve terminals: Ca2+ independence and role of integrins

NASA Technical Reports Server (NTRS)

Kashani, A. H.; Chen, B. M.; Grinnell, A. D.

2001-01-01

Hyperosmotic solutions cause markedly enhanced spontaneous quantal release of neurotransmitter from many nerve terminals. The mechanism of this enhancement is unknown. We have investigated this phenomenon at the frog neuromuscular junction with the aim of determining the degree to which it resembles the modulation of release by stretch, which has been shown to be mediated by mechanical tension on integrins.The hypertonicity enhancement, like the stretch effect, does not require Ca2+ influx or release from internal stores, although internal release may contribute to the effect. The hypertonicity effect is sharply reduced (but not eliminated) by peptides containing the RGD sequence, which compete with native ligands for integrin bonds.There is co-variance in the magnitude of the stretch and osmotic effects; that is, individual terminals exhibiting a large stretch effect also show strong enhancement by hypertonicity, and vice versa. The stretch and osmotic enhancements also can partially occlude each other.There remain some clear-cut differences between osmotic and stretch forms of modulation: the larger range of enhancement by hypertonic solutions, the relative lack of effect of osmolarity on evoked release, and the reported higher temperature sensitivity of osmotic enhancement. Nevertheless, our data strongly implicate integrins in a significant fraction of the osmotic enhancement, possibly acting via the same mechanism as stretch modulation.

A direct potential fitting RKR method: Semiclassical vs. quantal comparisons

NASA Astrophysics Data System (ADS)

Tellinghuisen, Joel

2016-12-01

Quantal and semiclassical (SC) eigenvalues are compared for three diatomic molecular potential curves: the X state of CO, the X state of Rb2, and the A state of I2. The comparisons show higher levels of agreement than generally recognized, when the SC calculations incorporate a quantum defect correction to the vibrational quantum number, in keeping with the Kaiser modification. One particular aspect of this is better agreement between quantal and SC estimates of the zero-point vibrational energy, supporting the need for the Y00 correction in this context. The pursuit of a direct-potential-fitting (DPF) RKR method is motivated by the notion that some of the limitations of RKR potentials may be innate, from their generation by an exact inversion of approximate quantities: the vibrational energy Gυ and rotational constant Bυ from least-squares analysis of spectroscopic data. In contrast, the DPF RKR method resembles the quantal DPF methods now increasingly used to analyze diatomic spectral data, but with the eigenvalues obtained from SC phase integrals. Application of this method to the analysis of 9500 assigned lines in the I2A ← X spectrum fails to alter the quantal-SC disparities found for the A-state RKR curve from a previous analysis. On the other hand, the SC method can be much faster than the quantal method in exploratory work with different potential functions, where it is convenient to use finite-difference methods to evaluate the partial derivatives required in nonlinear fitting.

Controlled On-chip Stimulation of Quantal Catecholamine Release from Chromaffin Cells Using Photolysis of Caged Ca2+ on Transparent Indium-Tin-Oxide Microchip Electrodes

PubMed Central

Chen, Xiaohui; Gao, Yuanfang; Hossain, Maruf; Gangopadhyay, Shubhra; Gillis, Kevin D.

2008-01-01

Photorelease of caged Ca2+ is a uniquely powerful tool to study the dynamics of Ca2+-triggered exocytosis from individual cells. Using photolithography and other microfabrication techniques, we have developed transparent microchip devices to enable photorelease of caged Ca2+ together with electrochemical detection of quantal catecholamine secretion from individual cells or cell arrays as a step towards developing high-throughput experimental devices. A 100 nm - thick transparent Indium-Tin-Oxide (ITO) film was sputter-deposited onto glass coverslips, which were then patterned into 24 cell-sized working electrodes (∼20 μm by 20 μm). We loaded bovine chromaffin cells with acetoxymethyl (AM) ester derivatives of the Ca2+ cage NP-EGTA and Ca2+ indicator dye Fura-4F, then transferred these cells onto the working ITO electrodes for amperometric recordings. Upon flash photorelease of caged Ca2+, a uniform rise of [Ca2+]i within the target cell leads to quantal release of oxidizable catecholamines measured amperometrically by the underlying ITO electrode. We observed a burst of amperometric spikes upon rapid elevation of [Ca2+]i and a “priming” effect of sub-stimulatory [Ca2+]i on the response of cells to subsequent [Ca2+]i elevation, similar to previous reports using different techniques. We conclude that UV photolysis of caged Ca2+ is a suitable stimulation technique for higher-throughput studies of Ca2+-dependent exocytosis on transparent electrochemical microelectrode arrays. PMID:18094774

Factors influencing immediate post-release survival of spectacled eiders following surgical implantation of transmitters with percutaneous antennae

USGS Publications Warehouse

Sexson, Matthew G.; Mulcahy, Daniel M.; Spriggs, Maria; Myers, Gwen E.

2014-01-01

Surgically implanted transmitters are a common method for tracking animal movements. Immediately following surgical implantation, animals pass through a critical recovery phase when behaviors may deviate from normal and the likelihood of individual survival may be reduced. Therefore, data collected during this period may be censored to minimize bias introduced by surgery-related behaviors or mortality. However, immediate post-release mortalities negate a sampling effort and reduce the amount of data potentially collected after the censoring period. Wildlife biologists should employ methods to support an animal’s survival through this period, but factors contributing to immediate post-release survival have not been formally assessed. We evaluated factors that potentially influenced the immediate post-release survival of 56 spectacled eiders (Somateria fischeri) marked with coelomically implanted satellite transmitters with percutaneous antennae in northern Alaska in 2010 and 2011. We modeled survival through the first 14 days following release and assessed the relative importance and effect of 15 covariates hypothesized to influence survival during this immediate post-release period. Estimated daily survival rate increased over the duration of the immediate post-release period; the probability of mortality was greatest within the first 5 days following release. Our top-ranking model included the effect of 2 blood analytes, pH and hematocrit, measured prior to surgical implantation of a transmitter. We found a positive response to pH; eiders exhibiting acidemia (low pH) prior to surgery were less likely to survive the immediate post-release period. We found a curvilinear response to hematocrit; eiders exhibiting extremely low or high pre-surgery hematocrit were also less likely to survive the immediate post-release period. In the interest of maximizing the survival of marked birds following release, hematological data obtained prior to surgical implantation of

Presynaptic membrane receptors in acetylcholine release modulation in the neuromuscular synapse.

PubMed

Tomàs, Josep; Santafé, Manel M; Garcia, Neus; Lanuza, Maria A; Tomàs, Marta; Besalduch, Núria; Obis, Teresa; Priego, Mercedes; Hurtado, Erica

2014-05-01

Over the past few years, we have studied, in the mammalian neuromuscular junction (NMJ), the local involvement in transmitter release of the presynaptic muscarinic ACh autoreceptors (mAChRs), purinergic adenosine autoreceptors (P1Rs), and trophic factor receptors (TFRs; for neurotrophins and trophic cytokines) during development and in the adult. At any given moment, the way in which a synapse works is largely the logical outcome of the confluence of these (and other) metabotropic signalling pathways on intracellular kinases, which phosphorylate protein targets and materialize adaptive changes. We propose an integrated interpretation of the complementary function of these receptors in the adult NMJ. The activity of a given receptor group can modulate a given combination of spontaneous, evoked, and activity-dependent release characteristics. For instance, P1Rs can conserve resources by limiting spontaneous quantal leak of ACh (an A1 R action) and protect synapse function, because stimulation with adenosine reduces the magnitude of depression during repetitive activity. The overall outcome of the mAChRs seems to contribute to upkeep of spontaneous quantal output of ACh, save synapse function by decreasing the extent of evoked release (mainly an M2 action), and reduce depression. We have also identified several links among P1Rs, mAChRs, and TFRs. We found a close dependence between mAChR and some TFRs and observed that the muscarinic group has to operate correctly if the tropomyosin-related kinase B receptor (trkB) is also to operate correctly, and vice versa. Likewise, the functional integrity of mAChRs depends on P1Rs operating normally. Copyright © 2014 Wiley Periodicals, Inc.

Locus of frequency-dependent depression identified with multiple-probability fluctuation analysis at rat climbing fibre-Purkinje cell synapses

PubMed Central

Silver, R Angus; Momiyama, Akiko; Cull-Candy, Stuart G

1998-01-01

, n = 5), but as the frequency of stimulation was increased, pr fell dramatically (0.02 ± 0.01 at 10 Hz, n = 4) with no apparent change in either q or N. This indicates that the observed 50-fold depression in EPSC amplitude is presynaptic in origin. Presynaptic frequency-dependent depression was investigated with double-pulse and multiple-pulse protocols. EPSC recovery, following simultaneous release at practically all sites, was slow, being well fitted by the sum of two exponential functions (time constants of 0.35 ± 0.09 and 3.2 ± 0.4 s, n = 5). EPSC recovery following sustained stimulation was even slower. We propose that presynaptic depression at CF synapses reflects a slow recovery of release probability following release of each quantum of transmitter. The large number of functional release sites, relatively large quantal size, and unusual dynamics of transmitter release at the CF synapse appear specialized to ensure highly reliable olivocerebellar transmission at low frequencies but to limit transmission at higher frequencies. PMID:9660900

Forskolin and protein kinase inhibitors differentially affect hair cell potassium currents and transmitter release at the cytoneural junction in the isolated frog labyrinth.

PubMed

Rossi, Maria Lisa; Rubbini, Gemma; Martini, Marta; Canella, Rita; Fesce, Riccardo

2017-08-15

The post-transductional elaboration of sensory input at the frog semicircular canal has been studied by correlating the effects of drugs that interfere with phosphorylation processes on: (i) potassium conductances in isolated hair cell and (ii) transmitter release at the cytoneural junction in the intact labyrinth. At hair cells, delayed potassium currents (IKD) undergo voltage- and time-dependent inactivation; inactivation removal requires ATP, is sensitive to kinase blockade, but is unaffected by exogenous application of cyclic nucleotides. We report here that forskolin, an activator of endogenous adenylyl cyclase, enhances IKD inactivation removal in isolated hair cells, but produces an overall decrease in IKD amplitude consistent with the direct blocking action of the drug on several families of K channels. In the intact labyrinth, forskolin enhances transmitter release, consistent with such depression of K conductances. Kinase blockers - H-89 and KT5823 - have been shown to reduce IKD inactivation removal and IKD amplitude at isolated hair cells. In the labyrinth, the effects of these drugs on junctional activity are quite variable, with predominant inhibition of transmitter release, rather than the enhancement expected from the impairment of K currents. The overall action of forskolin and kinase inhibitors on K conductances is similar (depression), but they have opposite effects on transmitter release: this indicates that some intermediate steps between the bioelectric control of hair cell membrane potential and transmitter release are affected in opposite ways and therefore are presumably regulated by protein phosphorylation. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Effect of rocuronium on the level and mode of pre-synaptic acetylcholine release by facial and somatic nerves, and changes following facial nerve injury in rabbits.

PubMed

Tan, Jinghua; Xu, Jing; Xing, Yian; Chen, Lianhua; Li, Shitong

2015-01-01

Muscles innervated by the facial nerve show differential sensitivities to muscle relaxants than muscles innervated by somatic nerves. The evoked electromyography (EEMG) response is also proportionally reduced after facial nerve injury. This forms the theoretical basis for proper utilization of muscle relaxants to balance EEMG monitoring and immobility under general anesthesia. (1) To observe the relationships between the level and mode of acetylcholine (ACh) release and the duration of facial nerve injury, and the influence of rocuronium in an in vitro rabbit model. (2) To explore the pre-synaptic mechanisms of discrepant responses to a muscle relaxant. Quantal and non-quantal ACh release were measured by using intracellular microelectrode recording in the orbicularis oris 1 to 42 days after graded facial nerve injury and in the gastrocnemius with/without rocuronium. Quantal ACh release was significantly decreased by rocuronium in the orbicularis oris and gastrocnemius, but significantly more so in gastrocnemius. Quantal release was reduced after facial nerve injury, which was significantly correlated with the severity of nerve injury in the absence but not in the presence of rocuronium. Non-quantal ACh release was reduced after facial nerve injury, with many relationships observed depending on the extent of the injury. The extent of inhibition of non-quantal release by rocuronium correlated with the grade of facial nerve injury. These findings may explain why EEMG amplitude might be diminished after acute facial nerve injury but relatively preserved after chronic injury and differential responses in sensitivity to rocuronium.

Effect of rocuronium on the level and mode of pre-synaptic acetylcholine release by facial and somatic nerves, and changes following facial nerve injury in rabbits

PubMed Central

Tan, Jinghua; Xu, Jing; Xing, Yian; Chen, Lianhua; Li, Shitong

2015-01-01

Muscles innervated by the facial nerve show differential sensitivities to muscle relaxants than muscles innervated by somatic nerves. The evoked electromyography (EEMG) response is also proportionally reduced after facial nerve injury. This forms the theoretical basis for proper utilization of muscle relaxants to balance EEMG monitoring and immobility under general anesthesia. (1) To observe the relationships between the level and mode of acetylcholine (ACh) release and the duration of facial nerve injury, and the influence of rocuronium in an in vitro rabbit model. (2) To explore the pre-synaptic mechanisms of discrepant responses to a muscle relaxant. Quantal and non-quantal ACh release were measured by using intracellular microelectrode recording in the orbicularis oris 1 to 42 days after graded facial nerve injury and in the gastrocnemius with/without rocuronium. Quantal ACh release was significantly decreased by rocuronium in the orbicularis oris and gastrocnemius, but significantly more so in gastrocnemius. Quantal release was reduced after facial nerve injury, which was significantly correlated with the severity of nerve injury in the absence but not in the presence of rocuronium. Non-quantal ACh release was reduced after facial nerve injury, with many relationships observed depending on the extent of the injury. The extent of inhibition of non-quantal release by rocuronium correlated with the grade of facial nerve injury. These findings may explain why EEMG amplitude might be diminished after acute facial nerve injury but relatively preserved after chronic injury and differential responses in sensitivity to rocuronium. PMID:25973033

Hexamethonium- and methyllycaconitine-induced changes in acetylcholine release from rat motor nerve terminals.

PubMed

Tian, L; Prior, C; Dempster, J; Marshall, I G

1997-11-01

1. The neuronal nicotinic receptor antagonists hexamethonium and methyllycaconitine (MLA) have been used to study the putative prejunctional nicotinic ACh receptors (AChRs) mediating a negative-feedback control of ACh release from motor nerve terminals in voltage-clamped rat phrenic nerve/ hemidiaphragm preparations. 2. Hexamethonium (200 microM), but not MLA (0.4-2.0 microM), decreased the time constant of decay of both endplate currents (e.p.cs) and miniature endplate currents (m.e.p.cs), indicating endplate ion channel block with hexamethonium. However, driving function analysis and reconvolution of e.p.cs and m.e.p.cs indicated that this ion channel block did not compromise the analysis of e.p.c. quantal content. 3. At low frequencies of stimulation (0.5-2 Hz), hexamethonium (200 microM) and MLA (2.0 microM) increased e.p.c. quantal content by 30-40%. At high frequencies (50-150 Hz) neither compound affected e.p.c. quantal content. All effects on quantal content were paralleled by changes in the size of the pool of quanta available for release. 4. The low frequency augmentation of e.p.c. quantal content by hexamethonium was absent when extracellular [Ca2+] was lowered from 2.0 to 0.5 mM. 5. At the concentrations studied, MLA and hexamethonium produced a small (10-20%) decrease in the peak amplitude of m.e.p.cs. 6. Neither apamin (100 nM) nor charybdotoxin (80 nM) had effects on spontaneous or nerve evoked current amplitudes at any frequency of stimulation. Thus the ability of nicotinic antagonists to augment e.p.c. quantal content is not due to inhibition of Ca(2+)-activated K(+)-channels. 7. We suggest that hexamethonium and MLA increase evoked ACh release by blocking prejunctional nicotinic AChRs. These receptors exert a negative feedback control over evoked ACh release and are probably of the alpha-bungarotoxin-insensitive neuronal type.

Hexamethonium- and methyllycaconitine-induced changes in acetylcholine release from rat motor nerve terminals

PubMed Central

Tian, >Lijun; Prior, Chris; Dempster, John; Marshall, Ian G

1997-01-01

The neuronal nicotinic receptor antagonists hexamethonium and methyllycaconitine (MLA) have been used to study the putative prejunctional nicotinic ACh receptors (AChRs) mediating a negative-feedback control of ACh release from motor nerve terminals in voltage-clamped rat phrenic nerve/hemidiaphragm preparations. Hexamethonium (200 μM), but not MLA (0.4–2.0 μM), decreased the time constant of decay of both endplate currents (e.p.cs) and miniature endplate currents (m.e.p.cs), indicating endplate ion channel block with hexamethonium. However, driving function analysis and reconvolution of e.p.cs and m.e.p.cs indicated that this ion channel block did not compromise the analysis of e.p.c. quantal content. At low frequencies of stimulation (0.5–2 Hz), hexamethonium (200 μM) and MLA (2.0 μM) increased e.p.c. quantal content by 30–40%. At high frequencies (50–150 Hz) neither compound affected e.p.c. quantal content. All effects on quantal content were paralleled by changes in the size of the pool of quanta available for release. The low frequency augmentation of e.p.c. quantal content by hexamethonium was absent when extracellular [Ca2+] was lowered from 2.0 to 0.5 mM. At the concentrations studied, MLA and hexamethonium produced a small (10–20%) decrease in the peak amplitude of m.e.p.cs. Neither apamin (100 nM) nor charybdotoxin (80 nM) had effects on spontaneous or nerve evoked current amplitudes at any frequency of stimulation. Thus the ability of nicotinic antagonists to augment e.p.c. quantal content is not due to inhibition of Ca2+-activated K+-channels. We suggest that hexamethonium and MLA increase evoked ACh release by blocking prejunctional nicotinic AChRs. These receptors exert a negative feedback control over evoked ACh release and are probably of the α-bungarotoxin-insensitive neuronal type. PMID:9401765

Interaction between protein kinase C and protein kinase A can modulate transmitter release at the rat neuromuscular synapse.

PubMed

Santafé, M M; Garcia, N; Lanuza, M A; Tomàs, M; Tomàs, J

2009-02-15

We used intracellular recording to investigate the functional interaction between protein kinase C (PKC) and protein kinase A (PKA) signal transduction cascades in the control of transmitter release in the neuromuscular synapses from adult rats. Our results indicate that: 1) PKA and PKC are independently involved in asynchronous release. 2) Evoked acetylcholine (ACh) release is enhanced with the PKA agonist Sp-8-BrcAMP and the PKC agonist phorbol ester (PMA). 3) PKA has a constitutive role in promoting a component of normal evoked transmitter release because, when the kinase is inhibited with H-89, the release diminishes. However, the PKC inhibitor calphostin C (CaC) does not affect ACh release. 4) PKA regulates neurotransmission without PKC involvement because, after PMA or CaC modulation of the PKC activity, coupling to the ACh release of PKA can normally be stimulated with Sp-8-BrcAMP or inhibited with H-89. 5) After PKA inhibition with H-89, PKC stimulation with PMA (or inhibition with CaC) does not lead to any change in evoked ACh release. However, in PKA-stimulated preparations with Sp-8-BrcAMP, PKC becomes tonically active, thus potentiating a component of release that can now be blocked with CaC. In normal conditions, therefore, PKA was able to modulate ACh release independently of PKC activity, whereas PKA stimulation caused the PKC coupling to evoked release. In contrast, PKA inhibition prevent PKC stimulation (with the phorbol ester) and coupling to ACh output. There was therefore some dependence of PKC on PKA activity in the fine control of the neuromuscular synaptic functionalism and ACh release.

Effects of Ca2+ channel blockers on transmitter release and presynaptic currents at the frog neuromuscular junction.

PubMed Central

Katz, E; Ferro, P A; Cherksey, B D; Sugimori, M; Llinás, R; Uchitel, O D

1995-01-01

1. The effects of the calcium channel blockers, funnel-web spider toxin (FTX), omega-agatoxin IVA (omega-Aga IVA) and omega-conotoxin GVIA (omega-CgTX), were tested on transmitter release and presynaptic currents in frog motor nerve endings. 2. Evoked transmitter release was blocked by FTX (IC50 = 0.02 microliter ml-1) and omega-CgTX (1 microM) but was not affected by omega-Aga IVA (0.5 microM). When FTX (0.1 microliter ml-1) was assayed on spontaneous release either in normal Ringer solution or in low Ca(2+)-high Mg2+ solution, it was found not to affect miniature endplate potential (MEPP) amplitude but to increase MEPP frequency by approximately 2-fold in both conditions. 3. Presynaptic calcium currents (ICa), measured by the perineurial technique in the presence of 10 mM tetraethylammonium chloride (TEA) and 200 microM BaCl2 to block K+ currents, were blocked by omega-CgTX (5 microM), partially blocked by FTX (1 microliter ml-1) and not affected by omega-Aga IVA (0.5 microM). 4. The presynaptic calcium-activated potassium current (IK(Ca)) measured by the perineurial technique in the presence of 0.5 microM 3,4-aminopyridine (DAP) to block voltage-dependent K+ currents, was strongly affected by charybdotoxin (ChTX) (300 nM) and completely abolished by BaCl2 (200 microM). This current was also blocked by omega-CgTX (5 microM) and by CdCl2 (200 microM) but was not affected by FTX (1 microliter ml-1). The blockade by omega-CgTX could not be reversed by elevating [Ca]o to 10 mM. 5. The results suggest that in frog synaptic terminals two omega-CgTX-sensitive populations might coexist. The transmitter release process seems to be mediated by calcium influx through a omega-CgTX- and FTX-sensitive population. PMID:7473230

Effects of Ca2+ channel blockers on transmitter release and presynaptic currents at the frog neuromuscular junction.

PubMed

Katz, E; Ferro, P A; Cherksey, B D; Sugimori, M; Llinás, R; Uchitel, O D

1995-08-01

1. The effects of the calcium channel blockers, funnel-web spider toxin (FTX), omega-agatoxin IVA (omega-Aga IVA) and omega-conotoxin GVIA (omega-CgTX), were tested on transmitter release and presynaptic currents in frog motor nerve endings. 2. Evoked transmitter release was blocked by FTX (IC50 = 0.02 microliter ml-1) and omega-CgTX (1 microM) but was not affected by omega-Aga IVA (0.5 microM). When FTX (0.1 microliter ml-1) was assayed on spontaneous release either in normal Ringer solution or in low Ca(2+)-high Mg2+ solution, it was found not to affect miniature endplate potential (MEPP) amplitude but to increase MEPP frequency by approximately 2-fold in both conditions. 3. Presynaptic calcium currents (ICa), measured by the perineurial technique in the presence of 10 mM tetraethylammonium chloride (TEA) and 200 microM BaCl2 to block K+ currents, were blocked by omega-CgTX (5 microM), partially blocked by FTX (1 microliter ml-1) and not affected by omega-Aga IVA (0.5 microM). 4. The presynaptic calcium-activated potassium current (IK(Ca)) measured by the perineurial technique in the presence of 0.5 microM 3,4-aminopyridine (DAP) to block voltage-dependent K+ currents, was strongly affected by charybdotoxin (ChTX) (300 nM) and completely abolished by BaCl2 (200 microM). This current was also blocked by omega-CgTX (5 microM) and by CdCl2 (200 microM) but was not affected by FTX (1 microliter ml-1). The blockade by omega-CgTX could not be reversed by elevating [Ca]o to 10 mM. 5. The results suggest that in frog synaptic terminals two omega-CgTX-sensitive populations might coexist. The transmitter release process seems to be mediated by calcium influx through a omega-CgTX- and FTX-sensitive population.

The quantal theory of how the immune system discriminates between "self and non-self"

PubMed

Smith, Kendall A

2004-12-17

In the past 50 years, immunologists have accumulated an amazing amount of information as to how the immune system functions. However, one of the most fundamental aspects of immunity, how the immune system discriminates between self vs. non-self, still remains an enigma. Any attempt to explain this most intriguing and fundamental characteristic must account for this decision at the level of the whole immune system, but as well, at the level of the individual cells making up the immune system. Moreover, it must provide for a molecular explanation as to how and why the cells behave as they do. The "Quantal Theory", proposed herein, is based upon the "Clonal Selection Theory", first proposed by Sir McFarland Burnet in 1955, in which he explained the remarkable specificity as well as diversity of recognition of everything foreign in the environment. The "Quantal Theory" is built upon Burnet's premise that after antigen selection of cell clones, a proliferative expansion of the selected cells ensues. Furthermore, it is derived from experiments which indicate that the proliferation of antigen-selected cell clones is determined by a quantal, "all-or-none", decision promulgated by a critical number of cellular receptors triggered by the T Cell Growth Factor (TCGF), interleukin 2 (IL2). An extraordinary number of experiments reported especially in the past 20 years, and detailed herein, indicate that the T cell Antigen Receptor (TCR) behaves similarly, and also that there are several critical numbers of triggered TCRs that determine different fates of the T cells. Moreover, the fates of the cells appear ultimately to be determined by the TCR triggering of the IL2 and IL2 receptor (IL2R) genes, which are also expressed in a very quantal fashion. The "Quantal Theory" states that the fundamental decisions of the T cell immune system are dependent upon the cells receiving a critical number of triggered TCRs and IL2Rs and that the cells respond in an all-or-none fashion. The

Transmitter release and presynaptic Ca2+ currents blocked by the spider toxin omega-Aga-IVA.

PubMed

Protti, D A; Uchitel, O D

1993-12-13

Mammalian neuromuscular transmission is resistant to L and N type calcium channel blockers but very sensitive to a low molecular weight funnel web spider venom toxin, FTX, which selectively blocks P type calcium channels. To further characterize the calcium channels involved in neuromuscular transmission we studied the effect of omega Agatoxin (omega-Aga-IVA) a polypeptide P type channel blocker from the same spider venom. We show that omega-Aga-IVA is a potent and irreversible inhibitor of the presynaptic Ca2+ currents and of acetylcholine release induced by electrical stimulation or by K+ depolarization. This provides further evidences that transmitter release at the mammalian neuromuscular junction is mediated by P type Ca2+ channels.

Quantal diffusion description of multinucleon transfers in heavy-ion collisions

NASA Astrophysics Data System (ADS)

Ayik, S.; Yilmaz, B.; Yilmaz, O.; Umar, A. S.

2018-05-01

Employing the stochastic mean-field (SMF) approach, we develop a quantal diffusion description of the multi-nucleon transfer in heavy-ion collisions at finite impact parameters. The quantal transport coefficients are determined by the occupied single-particle wave functions of the time-dependent Hartree-Fock equations. As a result, the primary fragment mass and charge distribution functions are determined entirely in terms of the mean-field properties. This powerful description does not involve any adjustable parameter, includes the effects of shell structure, and is consistent with the fluctuation-dissipation theorem of the nonequilibrium statistical mechanics. As a first application of the approach, we analyze the fragment mass distribution in 48Ca+ 238U collisions at the center-of-mass energy Ec.m.=193 MeV and compare the calculations with the experimental data.

Presynaptic inhibition of transmitter release from rat sympathetic neurons by bradykinin.

PubMed

Edelbauer, Hannah; Lechner, Stefan G; Mayer, Martina; Scholze, Thomas; Boehm, Stefan

2005-06-01

Bradykinin is known to stimulate neurons in rat sympathetic ganglia and to enhance transmitter release from their axons by interfering with the autoinhibitory feedback, actions that involve protein kinase C. Here, bradykinin caused a transient increase in the release of previously incorporated [3H] noradrenaline from primary cultures of dissociated rat sympathetic neurons. When this effect was abolished by tetrodotoxin, bradykinin caused an inhibition of tritium overflow triggered by depolarizing K+ concentrations. This inhibition was additive to that caused by the alpha2-adrenergic agonist UK 14304, desensitized within 12 min, was insensitive to pertussis toxin, and was enhanced when protein kinase C was inactivated. The effect was half maximal at 4 nm and antagonized competitively by the B2 receptor antagonist Hoe 140. The cyclooxygenase inhibitor indomethacin and the angiotensin converting enzyme inhibitor captopril did not alter the inhibition by bradykinin. The M-type K+ channel opener retigabine attenuated the secretagogue action of bradykinin, but left its inhibitory action unaltered. In whole-cell patch-clamp recordings, bradykinin reduced voltage-activated Ca2+ currents in a pertussis toxin-insensitive manner, and this action was additive to the inhibition by UK 14304. These results demonstrate that bradykinin inhibits noradrenaline release from rat sympathetic neurons via presynaptic B2 receptors. This effect does not involve cyclooxygenase products, M-type K+ channels, or protein kinase C, but rather an inhibition of voltage-gated Ca2+ channels.

Differential calcium dependence in basal and forskolin-potentiated spontaneous transmitter release in basolateral amygdala neurons.

PubMed

Miura, Yuki; Naka, Masamitsu; Matsuki, Norio; Nomura, Hiroshi

2012-10-31

Action potential-independent transmitter release, or spontaneous release, is postulated to produce multiple postsynaptic effects (e.g., maintenance of dendritic spines and suppression of local dendritic protein synthesis). Potentiation of spontaneous release may contribute to the precise modulation of synaptic function. However, the expression mechanism underlying potentiated spontaneous release remains unclear. In this study, we investigated the involvement of extracellular and intracellular calcium in basal and potentiated spontaneous release. Miniature excitatory postsynaptic currents (mEPSCs) of the basolateral amygdala neurons in acute brain slices were recorded. Forskolin, an adenylate cyclase activator, increased mEPSC frequency, and the increase lasted at least 25 min after washout. Removal of the extracellular calcium decreased mEPSC frequency in both naïve and forskolin-treated slices. On the other hand, chelation of intracellular calcium by BAPTA-AM decreased mEPSC frequency in naïve, but not in forskolin-treated slices. A blockade of the calcium-sensing receptor (CaSR) resulted in an increase in mEPSC frequency in forskolin-treated, but not in naïve slices. These findings indicate that forskolin-induced potentiation is accompanied by changes in the mechanisms underlying Ca(2+)-dependent spontaneous release. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

A Monte Carlo model reveals independent signaling at central glutamatergic synapses.

PubMed Central

Franks, Kevin M; Bartol, Thomas M; Sejnowski, Terrence J

2002-01-01

We have developed a biophysically realistic model of receptor activation at an idealized central glutamatergic synapse that uses Monte Carlo techniques to simulate the stochastic nature of transmission following release of a single synaptic vesicle. For the a synapse with 80 AMPA and 20 NMDA receptors, a single quantum, with 3000 glutamate molecules, opened approximately 3 NMDARs and 20 AMPARs. The number of open receptors varied directly with the total number of receptors, and the fraction of open receptors did not depend on the ratio of co-localized AMPARs and NMDARs. Variability decreased with increases in either total receptor number or quantal size, and differences between the variability of AMPAR and NMDAR responses were due solely to unequal numbers of receptors at the synapse. Despite NMDARs having a much higher affinity for glutamate than AMPARs, quantal release resulted in similar occupancy levels in both receptor types. Receptor activation increased with number of transmitter molecules released or total receptor number, whereas occupancy levels were only dependent on quantal size. Tortuous diffusion spaces reduced the extent of spillover and the activation of extrasynaptic receptors. These results support the conclusion that signaling is spatially independent within and between central glutamatergic synapses. PMID:12414671

The quantal nature of Ca2+ sparks and in situ operation of the ryanodine receptor array in cardiac cells.

PubMed

Wang, Shi Qiang; Stern, Michael D; Ríos, Eduardo; Cheng, Heping

2004-03-16

Intracellular Ca(2+) release in many types of cells is mediated by ryanodine receptor Ca(2+) release channels (RyRCs) that are assembled into two-dimensional paracrystalline arrays in the endoplasmic/sarcoplasmic reticulum. However, the in situ operating mechanism of the RyRC array is unknown. Here, we found that the elementary Ca(2+) release events, Ca(2+) sparks from individual RyRC arrays in rat ventricular myocytes, exhibit quantized Ca(2+) release flux. Analysis of the quantal property of Ca(2+) sparks provided a view of unitary Ca(2+) current and gating kinetics of the RyRC in intact cells and revealed that spark activation involves dynamic recruitment of small, variable cohorts of RyRCs. Intriguingly, interplay of RyRCs in multichannel sparks renders an unusual, thermodynamically irreversible mode of channel gating that is unshared by an RyRC acting solo, nor by RyRCs in vitro. Furthermore, an array-based inhibitory feedback, overriding the regenerative Ca(2+)-induced Ca(2+) release of RyRCs, provides a supramolecular mechanism for the microscopic stability of intracellular Ca(2+) signaling.

Role of the Intracellular Nucleoside Transporter ENT3 in Transmitter and High K+ Stimulation of Astrocytic ATP Release Investigated Using siRNA Against ENT3

PubMed Central

Song, Dan; Xu, Junnan; Bai, Qiufang; Cai, Liping; Hertz, Leif

2014-01-01

This study investigates the role of the intracellular adenosine transporter equilibrative nucleoside transporter 3 (ENT3) in stimulated release of the gliotransmitter adenosine triphosphate (ATP) from astrocytes. Within the past 20 years, our understanding of the importance of astrocytic handling of adenosine, its phosphorylation to ATP, and release of astrocytic ATP as an important transmitter has become greatly expanded. A recent demonstration that the mainly intracellular nucleoside transporter ENT3 shows much higher expression in freshly isolated astrocytes than in a corresponding neuronal preparation leads to the suggestion that it was important for the synthesis of gliotransmitter ATP from adenosine. This would be consistent with a previously noted delay in transmitter release of ATP in astrocytes but not in neurons. The present study has confirmed and quantitated stimulated ATP release in response to glutamate, adenosine, or an elevated K+ concentration from well-differentiated astrocyte cultures, measured by a luciferin–luciferase reaction. It showed that the stimulated ATP release was abolished by downregulation of ENT3 with small interfering RNA (siRNA), regardless of the stimulus. The concept that transmitter ATP in mature astrocytes is synthesized directly from adenosine prior to release is supported by the postnatal development of the expression of the vesicular transporter SLC17A9 in astrocytes. In neurons, this transporter carries ATP into synaptic vesicles, but in astrocytes, its expression is pronounced only in immature cells and shows a rapid decline during the first 3 postnatal weeks so that it has almost disappeared at the end of the third week in well-differentiated astrocytes, where its role has probably been taken over by ENT3. PMID:25298788

Leptin's effect on taste bud calcium responses and transmitter secretion.

PubMed

Meredith, Tricia L; Corcoran, Alan; Roper, Stephen D

2015-05-01

Leptin, a peptide hormone released by adipose tissue, acts on the hypothalamus to control cravings and appetite. Leptin also acts to decrease taste responses to sweet substances, though there is little detailed information regarding where leptin acts in the taste transduction cascade. The present study examined the effects of leptin on sweet-evoked responses and neuro transmitter release from isolated taste buds. Our results indicate that leptin moderately decreased sweet-evoked calcium mobilization in isolated mouse taste buds. We also employed Chinese hamster ovary biosensor cells to examine taste transmitter release from isolated taste buds. Leptin reduced ATP and increased serotonin release in response to sweet stimulation. However, leptin has no effect on bitter-evoked transmitter release, further showing that the action of leptin is sweet specific. Our results support those of previous studies, which state that leptin acts on taste tissue via the leptin receptor, most likely on Type II (Receptor) cells, but also possibly on Type III (Presynaptic) cells. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Adenosine receptors and muscarinic receptors cooperate in acetylcholine release modulation in the neuromuscular synapse.

PubMed

Santafe, M M; Priego, M; Obis, T; Garcia, N; Tomàs, M; Lanuza, M A; Tomàs, J

2015-07-01

Adenosine receptors (ARs) are present in the motor terminals at the mouse neuromuscular junction. ARs and the presynaptic muscarinic acetylcholine receptors (mAChRs) share the functional control of the neuromuscular junction. We analysed their mutual interaction in transmitter release modulation. In electrophysiological experiments with unaltered synaptic transmission (muscles paralysed by blocking the voltage-dependent sodium channel of the muscle cells with μ-conotoxin GIIIB), we found that: (i) a collaborative action between different AR subtypes reduced synaptic depression at a moderate activity level (40 Hz); (ii) at high activity levels (100 Hz), endogenous adenosine production in the synaptic cleft was sufficient to reduce depression through A1 -type receptors (A1 Rs) and A2 A-type receptors (A2 A Rs); (iii) when the non-metabolizable 2-chloroadenosine (CADO) agonist was used, both the quantal content and depression were reduced; (iv) the protective effect of CADO on depression was mediated by A1 Rs, whereas A2 A Rs seemed to modulate A1 Rs; (v) ARs and mAChRs absolutely depended upon each other for the modulation of evoked and spontaneous acetylcholine release in basal conditions and in experimental conditions with CADO stimulation; (vi) the purinergic and muscarinic mechanisms cooperated in the control of depression by sharing a common pathway although the purinergic control was more powerful than the muscarinic control; and (vii) the imbalance of the ARs created by using subtype-selective and non-selective inhibitory and stimulatory agents uncoupled protein kinase C from evoked transmitter release. In summary, ARs (A1 Rs, A2 A Rs) and mAChRs (M1 , M2 ) cooperated in the control of activity-dependent synaptic depression and may share a common protein kinase C pathway. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Metabotropic and ionotropic glutamate receptors mediate the modulation of acetylcholine release at the frog neuromuscular junction.

PubMed

Tsentsevitsky, Andrei; Nurullin, Leniz; Nikolsky, Evgeny; Malomouzh, Artem

2017-07-01

There is some evidence that glutamate (Glu) acts as a signaling molecule at vertebrate neuromuscular junctions where acetylcholine (ACh) serves as a neurotransmitter. In this study, performed on the cutaneous pectoris muscle of the frog Rana ridibunda, Glu receptor mechanisms that modulate ACh release processes were analyzed. Electrophysiological experiments showed that Glu reduces both spontaneous and evoked quantal secretion of ACh and synchronizes its release in response to electrical stimulation. Quisqualate, an agonist of ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptors and metabotropic Group I mGlu receptors, also exerted Glu-like inhibitory effects on the secretion of ACh but had no effect on the kinetics of quantal release. Quisqualate's inhibitory effect did not occur when a blocker of Group I mGlu receptors (LY 367385) or an inhibitor of phospholipase C (U73122) was present. An increase in the degree of synchrony of ACh quantal release, such as that produced by Glu, was obtained after application of N-methyl-D-aspartic acid (NMDA). The presence of Group I mGlu and NMDA receptors in the neuromuscular synapse was confirmed by immunocytochemistry. Thus, the data suggest that both metabotropic Group I mGlu receptors and ionotropic NMDA receptors are present at the neuromuscular synapse of amphibians, and that the activation of these receptors initiates different mechanisms for the regulation of ACh release from motor nerve terminals. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Aircraft-mounted crash-activated transmitter device

NASA Technical Reports Server (NTRS)

Manoli, R.; Ulrich, B. R. (Inventor)

1976-01-01

An aircraft crash location transmitter tuned to transmit on standard emergency frequencies is reported that is shock mounted in a sealed circular case atop the tail of an aircraft by means of a shear pin designed to fail under a G loading associated with a crash situation. The antenna for the transmitter is a metallic spring blade coiled like a spiral spring around the outside of the circular case. A battery within the case for powering the transmitter is kept trickle charged from the electrical system of the aircraft through a break away connector on the case. When a crash occurs, the resultant ejection of the case from the tail due to a failure of the shear pin releases the free end of the antenna which automatically uncoils. The accompanying separation of the connector effects closing of the transmitter key and results in commencement of transmission.

Utilization of alpha-ketoglutarate as a precursor for transmitter glutamate in cultured cerebellar granule cells.

PubMed

Peng, L A; Schousboe, A; Hertz, L

1991-01-01

Alpha-ketoglutarate together with an amino group donor (alanine) was shown to be able to serve as a precursor for the glutamate pool which is released by potassium-induced depolarization (i.e., transmitter glutamate) in cerebellar granule cells. However, these compounds could not be utilized as precursors for intracellular glutamate or for release of transmitter aspartate. The formation of transmitter glutamate was inhibited by the transamination inhibitor aminooxyacetic acid but not by phenylsuccinate, an inhibitor of the dicarboxylate carrier in the mitochondrial membrane. Both of these inhibitors have previously been found to inhibit synthesis of transmitter glutamate from glutamine. The results support the hypothesis that alpha-ketoglutarate and alanine undergo transmination in the cytosol to form pyruvate and glutamate, and that this glutamate pool is available for transmitter release of glutamate but does not constitute the major intracellular pool of glutamate.

Glutamate transporter EAAT4 in Purkinje cells controls intersynaptic diffusion of climbing fiber transmitter mediating inhibition of GABA release from interneurons.

PubMed

Satake, Shin'ichiro; Song, Si-Young; Konishi, Shiro; Imoto, Keiji

2010-12-01

Neurotransmitters diffuse out of the synaptic cleft and act on adjacent synapses to exert concerted control of the synaptic strength within neural pathways that converge on single target neurons. The excitatory transmitter released from climbing fibers (CFs), presumably glutamate, is shown to inhibit γ-aminobutyric acid (GABA) release at basket cell (BC)-Purkinje cell (PC) synapses in the rat cerebellar cortex through its extrasynaptic diffusion and activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors on BC axon terminals. This study aimed at examining how the CF transmitter-diffusion-mediated presynaptic inhibition is controlled by glutamate transporters. Pharmacological blockade of the PC-selective neuronal transporter EAAT4 markedly enhanced CF-induced inhibition of GABAergic transmission. Tetanic CF-stimulation elicited long-term potentiation of glutamate transporters in PCs, and thereby attenuated the CF-induced inhibition. Combined use of electrophysiology and immunohistochemistry revealed a significant inverse relationship between the level of EAAT4 expression and the inhibitory action of CF-stimulation on the GABA release at different cerebellar lobules - the CF-induced inhibition was profound in lobule III, where the EAAT4 expression level was low, whereas it was minimal in lobule X, where EAAT4 was abundant. The findings clearly demonstrate that the neuronal glutamate transporter EAAT4 in PCs plays a critical role in the extrasynaptic diffusion of CF transmitter - it appears not only to retrogradely determine the degree of CF-mediated inhibition of GABAergic inputs to the PC by controlling the glutamate concentration for intersynaptic diffusion, but also regulate synaptic information processing in the cerebellar cortex depending on its differential regional distribution as well as use-dependent plasticity of uptake efficacy. © 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience

The Role of Neurotrophins in Neurotransmitter Release

PubMed Central

Tyler, William J.; Perrett, Stephen P.; Pozzo-Miller, Lucas D.

2009-01-01

The neurotrophins (NTs) have recently been shown to elicit pronounced effects on quantal neurotransmitter release at both central and peripheral nervous system synapses. Due to their activity-dependent release, as well as the subcellular localization of both protein and receptor, NTs are ideally suited to modify the strength of neuronal connections by “fine-tuning” synaptic activity through direct actions at presynaptic terminals. Here, using BDNF as a prototypical example, the authors provide an update of recent evidence demonstrating that NTs enhance quantal neurotransmitter release at synapses through presynaptic mechanisms. The authors further propose that a potential target for NT actions at presynaptic terminals is the mechanism by which terminals retrieve synaptic vesicles after exocytosis. Depending on the temporal demands placed on synapses during high-frequency synaptic transmission, synapses may use two alternative modes of synaptic vesicle retrieval, the conventional slow endosomal recycling or a faster rapid retrieval at the active zone, referred to as “kiss-and-run.” By modulating Ca2+ microdomains associated with voltage-gated Ca2+ channels at active zones, NTs may elicit a switch from the slow to the fast mode of endocytosis of vesicles at presynaptic terminals during high-frequency synaptic transmission, allowing more reliable information transfer and neuronal signaling in the central nervous system. PMID:12467374

The role of neurotrophins in neurotransmitter release.

PubMed

Tyler, William J; Perrett, Stephen P; Pozzo-Miller, Lucas D

2002-12-01

The neurotrophins (NTs) have recently been shown to elicit pronounced effects on quantal neurotransmitter release at both central and peripheral nervous system synapses. Due to their activity-dependent release, as well as the subcellular localization of both protein and receptor, NTs are ideally suited to modify the strength of neuronal connections by "fine-tuning" synaptic activity through direct actions at presynaptic terminals. Here, using BDNF as a prototypical example, the authors provide an update of recent evidence demonstrating that NTs enhance quantal neurotransmitter release at synapses through presynaptic mechanisms. The authors further propose that a potential target for NT actions at presynaptic terminals is the mechanism by which terminals retrieve synaptic vesicles after exocytosis. Depending on the temporal demands placed on synapses during high-frequency synaptic transmission, synapses may use two alternative modes of synaptic vesicle retrieval, the conventional slow endosomal recycling or a faster rapid retrieval at the active zone, referred to as "kiss-and-run." By modulating Ca2+ microdomains associated with voltage-gated Ca2+ channels at active zones, NTs may elicit a switch from the slow to the fast mode of endocytosis of vesicles at presynaptic terminals during high-frequency synaptic transmission, allowing more reliable information transfer and neuronal signaling in the central nervous system.

Comparative study of quantal and semiclassical treatments of charge transfer between O+ and He

NASA Astrophysics Data System (ADS)

Zhao, L. B.; Joseph, D. C.; Saha, B. C.; Liebermann, H. P.; Funke, P.; Buenker, R. J.

2009-03-01

A comparative study for the electron capture process O+(S40,D20,P20)+He→O(P3)+He+ is reported. The cross sections are calculated using fully quantal and semiclassical molecular-orbital close-coupling (MOCC) approaches in the adiabatic representation. Detailed comparison of transition probabilities and cross sections is made from both MOCC approaches and displays close agreement above ˜125eV/u . The remarkable discrepancies between the earlier semiclassical and quantal MOCC approaches may be attributed to the insufficient step-size resolution in their semiclassical calculation [M. Kimura , Phys. Rev. A 50, 4854 (1994)]. Our results have also been compared with experiment and found to be in good agreement.

The P2Y(1) and P2Y(12) receptors mediate autoinhibition of transmitter release in sympathetic innervated tissues.

PubMed

Quintas, Clara; Fraga, Sónia; Gonçalves, Jorge; Queiroz, Glória

2009-12-01

In the sympathetic nervous system, ATP is a co-transmitter and modulator of transmitter release, inhibiting noradrenaline release by acting on P2Y autoreceptors, but in peripheral tissues the subtypes involved have only scarcely been identified. We investigated the identity of the noradrenaline release-inhibiting P2Y subtypes in the epididymal portion of vas deferens and tail artery of the rat. The subtypes operating as autoreceptors, the signalling mechanism and cross-talk with alpha(2)-autoreceptors, was also investigated in the epididymal portion. In both tissues, the nucleotides 2-methylthioATP, 2-methylthioADP, ADP and ATP inhibited noradrenaline release up to 68%, with the following order of potency: 2-methylthioADP=2-methylthioATP>ADP=ATP in the epididymal portion and 2-methylthioADP=2-methylthioATP=ADP>ATP in the tail artery. The selective P2Y(1) antagonist 2'-deoxy-N(6)-methyladenosine 3',5'-bisphosphate (30microM) and the P2Y(12) antagonist 2,2-dimethyl-propionic acid 3-(2-chloro-6-methylaminopurin-9-yl)-2-(2,2-dimethyl-propionyloxymethyl)-propyl ester (30microM) increased noradrenaline release per se by 25+/-8% and 18+/-3%, respectively, in the epididymal portion but not in tail artery. Both antagonists attenuated the effect of nucleotides in the epididymal portion whereas in tail artery only the P2Y(1) antagonist was effective. The agonist of P2Y(1) and P2Y(12) receptors, 2-methylthioADP, caused an inhibition of noradrenaline release that was not prevented by inhibition of phospholipase C or protein kinase C but was abolished by pertussis toxin. 2-methylthioADP and the adenosine A(1) receptor agonist N(6)-cyclopentyladenosine were less potent at inhibiting noradrenaline release under marked influence of alpha(2)-autoinhibition. In both tissues, nucleotides modulate noradrenaline release by activation of inhibitory P2Y(1) receptors but in the epididymal portion P2Y(12) receptors also participate. P2Y(1) and P2Y(12) receptors are coupled to G

A new potential energy surface for vibration-vibration coupling in HF-HF collisions. Formulation and quantal scattering calculations

NASA Astrophysics Data System (ADS)

Schwenke, David W.; Truhlar, Donald G.

1988-04-01

We present new ab initio calculations of the HF-HF interaction potential for the case where both molecules are simultaneously displaced from their equilibrium internuclear distance. These and previous ab initio calculations are then fit to a new analytic representation which is designed to be efficient to evaluate and to provide an especially faithful account of the forces along the vibrational coordinates. We use the new potential for two sets of quantal scattering calculations for collisions in three dimensions with total angular momentum zero. First we test that the angular harmonic representation of the anisotropy is adequate by comparing quantal rigid rotator calculations to those carried out for potentials involving higher angular harmonics and for which the expansion in angular harmonics is systematically increased to convergence. Then we carry out large-scale quantal calculations of vibration-vibration energy transfer including the coupling of both sets of vibrational and rotational coordinates. These calculations indicate that significant rotational energy transfer accompanies the vibration-to-vibration energy transfer process.

N-type Ca2+ channels mediate transmitter release at the electromotoneuron-electrocyte synapses of the weakly electric fish Gymnotus carapo.

PubMed

Sierra, F; Lorenzo, D; Macadar, O; Buño, W

1995-06-19

The effects of omega-conotoxin-GVIA (omega-CgTX) on synaptic transmission were studied in the electromotoneuron-electrocyte synapses of the electric organ (EO) of the weakly electric fish Gymnotus carapo. omega-CgTX selectively and irreversibly blocked excitatory postsynaptic potentials (EPSPs) in a dose dependent-manner. The toxin had no effect on: (a) resting postsynaptic membrane potential and conductance; (b) postsynaptic action potentials elicited by depolarizing transmembrane current pulses; (c) the action potential conduction in the presynaptic fiber; (d) acetylcholine (ACh)-induced postsynaptic responses. Nifedipine - a selective dihydropyridine antagonist of the L-type voltage-dependent Ca2+ channels (VDCCs) - did not affect synaptic transmission. Transmission was also undisturbed by the peptide omega-Agatoxin (omega-Aga-IVA), the low molecular weight polyamine, funnel-web toxin (FTX) - both included in the venom of the spider Agelenopsis aperta - and its synthetic analog sFTX, all selective blockers of P-type VDCCs. Since omega-CgTX irreversibly blocks the N-type VDCCs, we conclude that presynaptic N-type VDCCs mediate transmitter release at electromotoneuron terminals. The VDCCs involved in fish peripheral electromotoneuron-electrocyte presynaptic transmitter release are therefore similar to those in amphibian, reptilian and avian peripheral synapses, but differ from mammalian and invertebrate motoneuron terminals.

Stability of Mixed-Strategy-Based Iterative Logit Quantal Response Dynamics in Game Theory

PubMed Central

Zhuang, Qian; Di, Zengru; Wu, Jinshan

2014-01-01

Using the Logit quantal response form as the response function in each step, the original definition of static quantal response equilibrium (QRE) is extended into an iterative evolution process. QREs remain as the fixed points of the dynamic process. However, depending on whether such fixed points are the long-term solutions of the dynamic process, they can be classified into stable (SQREs) and unstable (USQREs) equilibriums. This extension resembles the extension from static Nash equilibriums (NEs) to evolutionary stable solutions in the framework of evolutionary game theory. The relation between SQREs and other solution concepts of games, including NEs and QREs, is discussed. Using experimental data from other published papers, we perform a preliminary comparison between SQREs, NEs, QREs and the observed behavioral outcomes of those experiments. For certain games, we determine that SQREs have better predictive power than QREs and NEs. PMID:25157502

Glutamate may be an efferent transmitter that elicits inhibition in mouse taste buds.

PubMed

Huang, Yijen A; Grant, Jeff; Roper, Stephen

2012-01-01

Recent studies suggest that l-glutamate may be an efferent transmitter released from axons innervating taste buds. In this report, we determined the types of ionotropic synaptic glutamate receptors present on taste cells and that underlie this postulated efferent transmission. We also studied what effect glutamate exerts on taste bud function. We isolated mouse taste buds and taste cells, conducted functional imaging using Fura 2, and used cellular biosensors to monitor taste-evoked transmitter release. The findings show that a large fraction of Presynaptic (Type III) taste bud cells (∼50%) respond to 100 µM glutamate, NMDA, or kainic acid (KA) with an increase in intracellular Ca(2+). In contrast, Receptor (Type II) taste cells rarely (4%) responded to 100 µM glutamate. At this concentration and with these compounds, these agonists activate glutamatergic synaptic receptors, not glutamate taste (umami) receptors. Moreover, applying glutamate, NMDA, or KA caused taste buds to secrete 5-HT, a Presynaptic taste cell transmitter, but not ATP, a Receptor cell transmitter. Indeed, glutamate-evoked 5-HT release inhibited taste-evoked ATP secretion. The findings are consistent with a role for glutamate in taste buds as an inhibitory efferent transmitter that acts via ionotropic synaptic glutamate receptors.

Implanting radio transmitters in wintering canvasbacks

USGS Publications Warehouse

Olsen, Glenn H.; Dein, F. Joshua; Haramis, G. Michael; Jorde, Dennis G.

1992-01-01

To conduct telemetry studies of wintering canvasbacks (Aythya valisineria) on Chesapeake Bay [Maryland, USA], we needed to devise a suitable method of radio transmitter attachment. We describe as aseptic, intraabdominal surgical technique, using the inhalation anesthetic isoflurane, to implant 20-g radio transmitters in free-ranging canvasbacks. We evaluated the technique over 3 winters (1987-89), when an annual average of 83 female canvasbacks received implant surgery during a 9-day period in mid-December. Of 253 ducks, 248 (98%) were implanted successfully, and 200 (80.65) completed the 70-day study until early March. No mortality or abnormal behavior from surgery was identified post-release.

P-type voltage-dependent calcium channel mediates presynaptic calcium influx and transmitter release in mammalian synapses.

PubMed Central

Uchitel, O D; Protti, D A; Sanchez, V; Cherksey, B D; Sugimori, M; Llinás, R

1992-01-01

We have studied the effect of the purified toxin from the funnel-web spider venom (FTX) and its synthetic analog (sFTX) on transmitter release and presynaptic currents at the mouse neuromuscular junction. FTX specifically blocks the omega-conotoxin- and dihydropyridine-insensitive P-type voltage-dependent Ca2+ channel (VDCC) in cerebellar Purkinje cells. Mammalian neuromuscular transmission, which is insensitive to N- or L-type Ca2+ channel blockers, was effectively abolished by FTX and sFTX. These substances blocked the muscle contraction and the neurotransmitter release evoked by nerve stimulation. Moreover, presynaptic Ca2+ currents recorded extracellularly from the interior of the perineural sheaths of nerves innervating the mouse levator auris muscle were specifically blocked by both natural toxin and synthetic analogue. In a parallel set of experiments, K(+)-induced Ca45 uptake by brain synaptosomes was also shown to be blocked or greatly diminished by FTX and sFTX. These results indicate that the predominant VDCC in the motor nerve terminals, and possibly in a significant percentage of brain synapses, is the P-type channel. Images PMID:1348859

P-type voltage-dependent calcium channel mediates presynaptic calcium influx and transmitter release in mammalian synapses.

PubMed

Uchitel, O D; Protti, D A; Sanchez, V; Cherksey, B D; Sugimori, M; Llinás, R

1992-04-15

We have studied the effect of the purified toxin from the funnel-web spider venom (FTX) and its synthetic analog (sFTX) on transmitter release and presynaptic currents at the mouse neuromuscular junction. FTX specifically blocks the omega-conotoxin- and dihydropyridine-insensitive P-type voltage-dependent Ca2+ channel (VDCC) in cerebellar Purkinje cells. Mammalian neuromuscular transmission, which is insensitive to N- or L-type Ca2+ channel blockers, was effectively abolished by FTX and sFTX. These substances blocked the muscle contraction and the neurotransmitter release evoked by nerve stimulation. Moreover, presynaptic Ca2+ currents recorded extracellularly from the interior of the perineural sheaths of nerves innervating the mouse levator auris muscle were specifically blocked by both natural toxin and synthetic analogue. In a parallel set of experiments, K(+)-induced Ca45 uptake by brain synaptosomes was also shown to be blocked or greatly diminished by FTX and sFTX. These results indicate that the predominant VDCC in the motor nerve terminals, and possibly in a significant percentage of brain synapses, is the P-type channel.

Neuro-transmitters in the central nervous system & their implication in learning and memory processes.

PubMed

Reis, Helton J; Guatimosim, Cristina; Paquet, Maryse; Santos, Magda; Ribeiro, Fabíola M; Kummer, Arthur; Schenatto, Grace; Salgado, João V; Vieira, Luciene B; Teixeira, Antônio L; Palotás, András

2009-01-01

This review article gives an overview of a number of central neuro-transmitters, which are essential for integrating many functions in the central nervous system (CNS), such as learning, memory, sleep cycle, body movement, hormone regulation and many others. Neurons use neuro-transmitters to communicate, and a great variety of molecules are known to fit the criteria to be classified as such. A process shared by all neuro-transmitters is their release by excocytosis, and we give an outline of the molecular events and protein complexes involved in this mechanism. Synthesis, transport, inactivation, and cellular signaling can be very diverse when different neuro-transmitters are compared, and these processes are described separately for each neuro-transmitter system. Here we focus on the most well known neuro-transmitters: acetyl-choline, catechol-amines (dopamine and nor-adrenalin), indole-amine (serotonin), glutamate, and gamma-amino-butyric acid (GABA). Glutamate is the major excitatory neuro-transmitter in the brain and its actions are counter-balanced by GABA, which is the major inhibitory substance in the CNS. A balance of neuronal transmission between these two neuro-transmitters is essential to normal brain function. Acetyl-choline, serotonin and catechol-amines have a more modulatory function in the brain, being involved in many neuronal circuits. Apart from summarizing the current knowledge about the synthesis, release and receptor signaling of these transmitters, some disease states due to alteration of their normal neuro-transmission are also described.

pKI values of prazosin and idazoxan for receptors stimulated by neuronally released transmitter in the epididymal portion of rat isolated vas deferens.

PubMed

Mackay, D; Kengatharan, M

1994-01-01

1. A new method has been used to measure pKI values of prazosin and idazoxan against neuronally-released transmitter in the epididymal portion of the rat isolated vas deferens. The most reproducible results were obtained with a prolonged antagonist equilibration time (1 h). 2. Under these conditions the pKI of prazosin was practically unaffected by addition of alpha, beta-methylene-adenosine-5'-triphosphate (10 microM) to desensitize purinoceptors. Addition of desmethylimipramine (DMI) (0.3 microM) produced a small, but statistically non-significant, reduction. 3. The same method has been used to measure the pKI of prazosin against exogenous noradrenaline. In the latter case addition of DMI (0.3 microM) and corticosterone (30 microM) together produced a statistically significant reduction in the apparent pKI of prazosin. 4. The new method for estimating pKI values shows that DMI itself acts either pseudo-irreversibly or non-competitively and may be reducing the apparent pKI of prazosin. 5. The pKI values obtained for prazosin and idazoxan against neuronally-released transmitter are in good agreement with those obtained by other workers for the actions of these drugs on alpha-adrenoceptors.

The mechanism of action of aniracetam at synaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors: indirect and direct effects on desensitization.

PubMed

Lawrence, J Josh; Brenowitz, Stephan; Trussell, Laurence O

2003-08-01

The mechanism of action of aniracetam on alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors was examined in outside-out patches and at glutamatergic synapses in neurons of the chick cochlear nucleus. A combination of rapid-flow analysis, using glutamate as an agonist, and kinetic modeling indicated that aniracetam slows both the rate of channel closing, and the microscopic rates of desensitization, even for partially liganded receptors. Little effect was observed on the rate of recovery from desensitization or on the response to the weakly desensitizing agonist kainate. Aniracetam's effects on receptor deactivation saturated at lower concentrations than its effects on desensitization, suggesting that cooperativity between homologous binding sites was required to regulate desensitization. Analysis of responses to paired pulses of agonist also indicated that AMPA receptors must desensitize partially even after agonist exposures too brief to permit rebinding. In the presence of aniracetam, evoked excitatory synaptic currents (EPSCs) and miniature EPSCs in low quantal-content conditions had decay times similar to the time course of receptor deactivation. Under these conditions, the time course of both transmitter release and clearance must be <1 to 2 ms. However, in high quantal-content conditions, the evoked EPSC in aniracetam decayed with a time course intermediate between deactivation and desensitization, suggesting that the time course of transmitter clearance is prolonged because of pooling of transmitter in the synaptic cleft. Moreover, by comparing the amounts of paired-pulse synaptic depression and patch desensitization prevented by aniracetam, we conclude that significant desensitization occurs in response to rebinding of transmitter to the AMPA receptors.

The Quantal Larynx: The Stable Regions of Laryngeal Biomechanics and Implications for Speech Production.

PubMed

Moisik, Scott Reid; Gick, Bryan

2017-03-01

Recent proposals suggest that (a) the high dimensionality of speech motor control may be reduced via modular neuromuscular organization that takes advantage of intrinsic biomechanical regions of stability and (b) computational modeling provides a means to study whether and how such modularization works. In this study, the focus is on the larynx, a structure that is fundamental to speech production because of its role in phonation and numerous articulatory functions. A 3-dimensional model of the larynx was created using the ArtiSynth platform (http://www.artisynth.org). This model was used to simulate laryngeal articulatory states, including inspiration, glottal fricative, modal prephonation, plain glottal stop, vocal-ventricular stop, and aryepiglotto-epiglottal stop and fricative. Speech-relevant laryngeal biomechanics is rich with "quantal" or highly stable regions within muscle activation space. Quantal laryngeal biomechanics complement a modular view of speech control and have implications for the articulatory-biomechanical grounding of numerous phonetic and phonological phenomena.

Intestinal and peritoneal mast cells differ in kinetics of quantal release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balseiro-Gomez, Santiago, E-mail: sanbalgom@alum.us.es; Ramirez-Ponce, M. Pilar, E-mail: pponce@us.es; Acosta, Jorge, E-mail: jorgealo@us.es

2016-01-15

5-hydroxytriptamine (5-HT, serotonin) storage and release in mast cell (MC) secretory granules (SG) are dependent on serglycin proteoglycans (PG). This notion is based on the studies of MC of the connective tissue subtype that predominantly contain PG of the heparin type, whereas intestinal mucosal MC, which contain predominantly chondroitin sulfate, have been poorly explored. In the present study, we addressed the possibility that PG contents may differently affect the storage and release of preformed mediators in these two MC subclasses and explain in part their different functional properties. Rat peritoneal (PMC) and intestinal mast cells (IMC) were isolated and purifiedmore » using a percoll gradient, and the efflux of 5-HT from each SG was measured by amperometric detection. IMC exhibited a ∼34% reduction in the release of 5-HT compared with PMC because of a lower number of exocytotic events, rather than a lower secretion per single exocytotic event. Amperometric spikes from IMC exhibited a slower decay phase and increased half-width but a similar ascending phase and foot parameters, indicating that the fusion pore kinetics are comparable in both MC subclasses. We conclude that both PG subtypes are equally efficient systems, directly involved in serotonin accumulation, and play a crucial role in regulating the kinetics of exocytosis from SG, providing specific secretory properties for the two cellular subtypes. - Highlights: • We improved a method for isolating and purifying IMC. • There was a reduction in total serotonin release in IMC with respect to PMC. • This decrease was not due to less secretion per quantum but a lower number of exocytotic events. • There was also a deceleration of exocytosis in IMC with respect to PMC.« less

Performance of implantable satellite transmitters in diving seabirds

USGS Publications Warehouse

Hatch, Shyla A.; Meyers, P.M.; Mulcahy, D.M.; Douglas, David C.

2000-01-01

We report on the first deployment of satellite transmitters in large alcids. In 1995 and 1996, we surgically implanted 51 transmitters in Common and Thick-billed murres (Uria aalge and U. lomvia) and Tufted Puffins (Fratercula cirrhata) at three colonies in Alaska. These devices furnished more than 2,900 locations over succeeding months (eight months maximum transmitter life), some 30-40% of which had calculated errors of <1,000 m. We considered other data to be reliable if locations were repetitive within a short period of time. As measures of data collection efficiency, we calculated location indices (number of locations per hour of transmission) of 0.44 during the breeding season and 0.35 overall. Those values compared favorably with satellite transmitters previously deployed on large mammals at similar latitudes. Transmitters did not last as long as expected because lithium batteries tended to self-discharge when kept at the high internal temperature of a bird. Most importantly, we encountered high mortality of instrumented birds, especially in the interval from 11-20 days after release. Our results suggest that radio transmission itself somehow impaired normal feeding behavior or otherwise compromised the birds' health. Those two problems (battery life and bird mortality) will need to be solved before implantable devices can be applied effectively to the same or similar species in the future. Received 24 August 1999, accepted 10 October 1999.

Functional implications of neurotransmitter co-release: glutamate and GABA share the load.

PubMed

Seal, Rebecca P; Edwards, Robert H

2006-02-01

For decades it has been thought that a neuron releases only one classical neurotransmitter from all of its processes. However, recent work has shown that most neuronal populations release more than one classical transmitter, and indeed that the transmitters can be segregated into different processes of the same neuron. Glutamate and gamma-aminobutyric acid, the major excitatory and inhibitory neurotransmitters in the mammalian central nervous system, appear to be co-released with most other transmitters, as well as with each other. The release of multiple transmitters by the same neuron enhances the spatial and temporal control of synaptic transmission. Moreover, dynamic regulation of neurotransmitter phenotypes increases the plasticity of neurotransmission, indicating potential avenues for therapeutic intervention.

Preening behavior of adult gyrfalcons tagged with backpack transmitters

USGS Publications Warehouse

Booms, T.L.; Schempf, P.F.; Fuller, M.R.

2011-01-01

Radio transmitters provide data that enhance understanding of raptor biology (Walls and Kenward 2007) and are now used to answer a multitude of research questions (Meyburg and Fuller 2007). However, transmitters affect the birds that carry them (Barron et al. 2010), and it is important to document and evaluate such effects (Casper 2009). For example, decreased survival has been documented in Prairie Falcons (Falco mexicanus; Steenhof et al. 2006), Northern Goshawks (Accipiter gentilis; Reynolds et al. 2004), and Spotted Owls (Strix occidentalis; Paton et al. 1991) tagged with radio transmitters. However, no such effects were reported for Peregrine Falcons (Falco peregrinus; Fuller et al. 1998, McGrady et al. 2002) and a number of other species (Kenward 2001). White and Garrott (1990) noted that in general, animals tagged with radio transmitters often altered their behaviors for 1–14 d after release during an adjustment period that included increased preening and grooming frequencies. Although more than 90 Gyrfalcons (Falco rusticolus) have been tagged with radio transmitters (e.g., Burnham 2007, McIntyre et al. 2009, T. Booms unpubl. data), the effects of transmitters on this species are not well documented. Anecdotal information suggests some Gyrfalcons might be negatively affected by radio-tagging (Booms et al. 2008). As part of a study investigating Gyrfalcon breeding biology, we conducted opportunistic, focused observations on two radio-tagged adult female Gyrfalcons and their unmarked mates. We here describe and quantify preening behavior of Gyrfalcons shortly after radio-tagging.

Metabolic Control of Vesicular Glutamate Transport and Release

PubMed Central

Juge, Narinobu; Gray, John A.; Omote, Hiroshi; Miyaji, Takaaki; Inoue, Tsuyoshi; Hara, Chiaki; Uneyama, Hisayuki; Edwards, Robert H.; Nicoll, Roger A.; Moriyama, Yoshinori

2010-01-01

Fasting has been used to control epilepsy since antiquity, but the mechanism of coupling between metabolic state and excitatory neurotransmission remains unknown. Previous work has shown that the vesicular glutamate transporters (VGLUTs) required for exocytotic release of glutamate undergo an unusual form of regulation by Cl−. Using functional reconstitution of the purified VGLUTs into proteoliposomes, we now show that Cl− acts as an allosteric activator, and the ketone bodies that increase with fasting inhibit glutamate release by competing with Cl− at the site of allosteric regulation. Consistent with these observations, acetoacetate reduced quantal size at hippocampal synapses, and suppresses glutamate release and seizures evoked with 4-aminopyridine in the brain. The results indicate an unsuspected link between metabolic state and excitatory neurotransmission through anion-dependent regulation of VGLUT activity. PMID:20920794

Metabolic control of vesicular glutamate transport and release.

PubMed

Juge, Narinobu; Gray, John A; Omote, Hiroshi; Miyaji, Takaaki; Inoue, Tsuyoshi; Hara, Chiaki; Uneyama, Hisayuki; Edwards, Robert H; Nicoll, Roger A; Moriyama, Yoshinori

2010-10-06

Fasting has been used to control epilepsy since antiquity, but the mechanism of coupling between metabolic state and excitatory neurotransmission remains unknown. Previous work has shown that the vesicular glutamate transporters (VGLUTs) required for exocytotic release of glutamate undergo an unusual form of regulation by Cl(-). Using functional reconstitution of the purified VGLUTs into proteoliposomes, we now show that Cl(-) acts as an allosteric activator, and the ketone bodies that increase with fasting inhibit glutamate release by competing with Cl(-) at the site of allosteric regulation. Consistent with these observations, acetoacetate reduced quantal size at hippocampal synapses and suppresses glutamate release and seizures evoked with 4-aminopyridine in the brain. The results indicate an unsuspected link between metabolic state and excitatory neurotransmission through anion-dependent regulation of VGLUT activity. Copyright © 2010 Elsevier Inc. All rights reserved.

Effects of hemicholinium and bretylium on the release of autonomic transmitters in the isolated sino-atrial node

PubMed Central

Appel, W. C.; Vincenzi, F. F.

1970-01-01

1. In the isolated, spontaneously beating, sino-atrial node of the rabbit selective electrical excitation of intranodal autonomic nerve fibres results in a biphasic chronotropic response. This chronotropic response (negative followed by positive chronotropism) is due to the release of the autonomic transmitters (acetylcholine and noradrenaline, respectively) from intranodal nerve fibres. 2. In the presence of 2 × 10-4 g/ml hemicholinium, the negative chronotropic (cholinergic) response is abolished while the positive chronotropic (adrenergic) response is unaltered. 3. In the presence of 5 × 10-6 g/ml bretylium, the positive chronotropic response is abolished while the negative chronotropic response is little affected. 4. After blockade of the negative chronotropic response by hemicholinium, bretylium abolishes the remaining positive chronotropic response. The effect of bretylium is not altered in the presence of hemicholinium. 5. Considering currently accepted mechanisms of action for hemicholinium and bretylium, the results of these experiments do not lend support to the cholinergic link hypothesis of adrenergic neuro-effector transmission. PMID:5492897

Effects of hemicholinium and bretylium on the release of autonomic transmitters in the isolated sino-atrial node.

PubMed

Appel, W C; Vincenzi, F F

1970-10-01

1. In the isolated, spontaneously beating, sino-atrial node of the rabbit selective electrical excitation of intranodal autonomic nerve fibres results in a biphasic chronotropic response. This chronotropic response (negative followed by positive chronotropism) is due to the release of the autonomic transmitters (acetylcholine and noradrenaline, respectively) from intranodal nerve fibres.2. In the presence of 2 x 10(-4) g/ml hemicholinium, the negative chronotropic (cholinergic) response is abolished while the positive chronotropic (adrenergic) response is unaltered.3. In the presence of 5 x 10(-6) g/ml bretylium, the positive chronotropic response is abolished while the negative chronotropic response is little affected.4. After blockade of the negative chronotropic response by hemicholinium, bretylium abolishes the remaining positive chronotropic response. The effect of bretylium is not altered in the presence of hemicholinium.5. Considering currently accepted mechanisms of action for hemicholinium and bretylium, the results of these experiments do not lend support to the cholinergic link hypothesis of adrenergic neuro-effector transmission.

Activation of M1 muscarinic receptors triggers transmitter release from rat sympathetic neurons through an inhibition of M-type K+ channels.

PubMed

Lechner, Stefan G; Mayer, Martina; Boehm, Stefan

2003-12-15

the basis for the stimulation of transmitter release from sympathetic neurons via M1 muscarinic receptors.

The cardiac sympathetic co-transmitter galanin reduces acetylcholine release and vagal bradycardia: Implications for neural control of cardiac excitability

PubMed Central

Herring, Neil; Cranley, James; Lokale, Michael N.; Li, Dan; Shanks, Julia; Alston, Eric N.; Girard, Beatrice M.; Carter, Emma; Parsons, Rodney L.; Habecker, Beth A.; Paterson, David J.

2012-01-01

The autonomic phenotype of congestive cardiac failure is characterised by high sympathetic drive and impaired vagal tone, which are independent predictors of mortality. We hypothesize that impaired bradycardia to peripheral vagal stimulation following high-level sympathetic drive is due to sympatho-vagal crosstalk by the adrenergic co-transmitters galanin and neuropeptide-Y (NPY). Moreover we hypothesize that galanin acts similarly to NPY by reducing vagal acetylcholine release via a receptor mediated, protein kinase-dependent pathway. Prolonged right stellate ganglion stimulation (10 Hz, 2 min, in the presence of 10 μM metoprolol) in an isolated guinea pig atrial preparation with dual autonomic innervation leads to a significant (p < 0.05) reduction in the magnitude of vagal bradycardia (5 Hz) maintained over the subsequent 20 min (n = 6). Immunohistochemistry demonstrated the presence of galanin in a small number of tyrosine hydroxylase positive neurons from freshly dissected stellate ganglion tissue sections. Following 3 days of tissue culture however, most stellate neurons expressed galanin. Stellate stimulation caused the release of low levels of galanin and significantly higher levels of NPY into the surrounding perfusate (n = 6, using ELISA). The reduction in vagal bradycardia post sympathetic stimulation was partially reversed by the galanin receptor antagonist M40 after 10 min (1 μM, n = 5), and completely reversed with the NPY Y2 receptor antagonist BIIE 0246 at all time points (1 μM, n = 6). Exogenous galanin (n = 6, 50–500 nM) also reduced the heart rate response to vagal stimulation but had no effect on the response to carbamylcholine that produced similar degrees of bradycardia (n = 6). Galanin (500 nM) also significantly attenuated the release of 3H-acetylcholine from isolated atria during field stimulation (5 Hz, n = 5). The effect of galanin on vagal bradycardia could be abolished by the galanin receptor antagonist

P-type Ca2+ channels mediate excitatory and inhibitory synaptic transmitter release in crayfish muscle.

PubMed

Araque, A; Clarac, F; Buño, W

1994-05-10

The toxin fraction (FTX) and peptide omega-Aga-IVA from the venom of the funnel-web spider Agelenopsis aperta, as well as a synthetic analogue of FTX, specifically block the P-type voltage-dependent Ca2+ channel (VDCC). The effects of these toxins on synaptic transmission were studied in the neuromuscular synapses of the crayfish opener muscle, which has a single excitatory and a single inhibitory motoneuron. FTX selectively and reversibly blocked excitatory and inhibitory postsynaptic currents and potentials in a dose-dependent manner. FTX had no effect on (i) resting and postsynaptic membrane conductance, (ii) postsynaptic L-type VDCC, and (iii) both glutamate- and gamma-aminobutyric acid-induced postsynaptic responses. Mean amplitude and frequency of miniature postsynaptic potentials were unchanged by FTX. The postsynaptic VDCC was inhibited by nifedipine, a selective dihydropyridine antagonist of L-type VDCC, whereas synaptic transmission was unaffected. Transmission was also undisturbed by omega-conotoxin, suggesting that N-type VDCCs are not involved. The peptide omega-Aga-IVA blocked excitatory and inhibitory transmission without affecting postsynaptic VDCC. Synaptic transmission was also blocked by synthetic FTX. We conclude that presynaptic P-type VDCCs are involved in both evoked excitatory and inhibitory transmitter release in crayfish neuromuscular synapses.

P-type Ca2+ channels mediate excitatory and inhibitory synaptic transmitter release in crayfish muscle.

PubMed Central

Araque, A; Clarac, F; Buño, W

1994-01-01

The toxin fraction (FTX) and peptide omega-Aga-IVA from the venom of the funnel-web spider Agelenopsis aperta, as well as a synthetic analogue of FTX, specifically block the P-type voltage-dependent Ca2+ channel (VDCC). The effects of these toxins on synaptic transmission were studied in the neuromuscular synapses of the crayfish opener muscle, which has a single excitatory and a single inhibitory motoneuron. FTX selectively and reversibly blocked excitatory and inhibitory postsynaptic currents and potentials in a dose-dependent manner. FTX had no effect on (i) resting and postsynaptic membrane conductance, (ii) postsynaptic L-type VDCC, and (iii) both glutamate- and gamma-aminobutyric acid-induced postsynaptic responses. Mean amplitude and frequency of miniature postsynaptic potentials were unchanged by FTX. The postsynaptic VDCC was inhibited by nifedipine, a selective dihydropyridine antagonist of L-type VDCC, whereas synaptic transmission was unaffected. Transmission was also undisturbed by omega-conotoxin, suggesting that N-type VDCCs are not involved. The peptide omega-Aga-IVA blocked excitatory and inhibitory transmission without affecting postsynaptic VDCC. Synaptic transmission was also blocked by synthetic FTX. We conclude that presynaptic P-type VDCCs are involved in both evoked excitatory and inhibitory transmitter release in crayfish neuromuscular synapses. Images PMID:7910404

Development of antibacterial and high light transmittance bulk materials: Incorporation and sustained release of hydrophobic or hydrophilic antibiotics.

PubMed

Wang, Bailiang; Liu, Huihua; Zhang, Binjun; Han, Yuemei; Shen, Chenghui; Lin, Quankui; Chen, Hao

2016-05-01

Infection associated with medical devices is one of the most frequent complications of modern medical biomaterials. Bacteria have a strong ability to attach on solid surfaces, forming colonies and subsequently biofilms. In this work, a novel antibacterial bulk material was prepared through combining poly(dimethyl siloxane) (PDMS) with either hydrophobic or hydrophilic antibiotics (0.1-0.2 wt%). Scanning electron microscopy, water contact angle and UV-vis spectrophotometer were used to measure the changes of surface topography, wettability and optical transmission. For both gentamicin sulfate (GS) and triclosan (TCA), the optical transmission of the PDMS-GS and PDMS-TCA blend films was higher than 90%. Drug release studies showed initial rapid release and later sustained release of GS or TCA under aqueous physiological conditions. The blend films demonstrated excellent bactericidal and sufficient biofilm inhibition functions against Gram-positive bacteria (Staphylococcus aureus, S. aureus) measured by LIVE/DEAD bacterial viability kit staining method. Kirby-Bauer method showed that there was obvious zone of inhibition (7.5-12.5mm). Cytocompatibility assessment against human lens epithelial cells (HLECs) revealed that the PDMS-GS blend films had good cytocompatibility. However, the PDMS-TCA blend films showed certain cytotoxicity against HLECs. The PDMS-0.2 wt% GS blend films were compared to native PDMS in the rabbit subcutaneous S. aureus infection model. The blend films yielded a significantly lower degree of infection than native PDMS at day 7. The achievement of the PDMS-drug bulk materials with high light transmittance, excellent bactericidal function and good cytocompatibility can potentially be widely used as bio-optical materials. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Functional support of glutamate as a vestibular hair cell transmitter in an amniote

NASA Technical Reports Server (NTRS)

Cochran, S. L.; Correia, M. J.

1995-01-01

Although hair cells in the cochlea and in the vestibular endorgans of anamniotes are thought to release glutamate or a similar compound as their transmitter, there is little evidence in amniotes (which, unlike anamniotes, possess both type I and II hair cells) as to the nature of the hair cell transmitters in the vestibular labyrinth. We have recorded extracellularly from single semicircular canal afferents in the turtle labyrinth maintained in vitro and have bath-applied a number of transmitter agonists and antagonists to relate the effects of these substances to the actions of the endogenous transmitter substances. Both glutamate and aspartate strongly excite the afferents while GABA and carbachol have negligible or weak effects. In contrast to its lack of effect on afferent activity in some anamniotes, N-methyl-D-aspartate (NMDA) was also found to excite these afferents. Kynurenic acid reversibly reduced the resting firing rates of the afferents and the increases in firing due to the application of glutamate and aspartate. These findings provide preliminary support for the hypothesis that glutamate (or a related compound) is also a vestibular hair cell transmitter in amniotes.

Striatal dopamine neurotransmission: regulation of release and uptake

PubMed Central

Sulzer, David; Cragg, Stephanie J.; Rice, Margaret E.

2016-01-01

Dopamine (DA) transmission is governed by processes that regulate release from axonal boutons in the forebrain and the somatodendritic compartment in midbrain, and by clearance by the DA transporter, diffusion, and extracellular metabolism. We review how axonal DA release is regulated by neuronal activity and by autoreceptors and heteroreceptors, and address how quantal release events are regulated in size and frequency. In brain regions densely innervated by DA axons, DA clearance is due predominantly to uptake by the DA transporter, whereas in cortex, midbrain, and other regions with relatively sparse DA inputs, the norepinephrine transporter and diffusion are involved. We discuss the role of DA uptake in restricting the sphere of influence of DA and in temporal accumulation of extracellular DA levels upon successive action potentials. The tonic discharge activity of DA neurons may be translated into a tonic extracellular DA level, whereas their bursting activity can generate discrete extracellular DA transients. PMID:27141430

Transmitter release modulation in nerve terminals of rat neocortical pyramidal cells by intracellular calcium buffers

PubMed Central

Ohana, Ora; Sakmann, Bert

1998-01-01

Dual whole-cell voltage recordings were made from synaptically connected layer 5 (L5) pyramidal neurones in slices of the young (P14-P16) rat neocortex. The Ca2+ buffers BAPTA or EGTA were loaded into the presynaptic neurone via the pipette recording from the presynaptic neurone to examine their effect on the mean and the coefficient of variation (c.v.) of single fibre EPSP amplitudes, referred to as unitary EPSPs. The fast Ca2+ buffer BAPTA reduced unitary EPSP amplitudes in a concentration dependent way. With 0.1 mm BAPTA in the pipette, the mean EPSP amplitude was reduced by 14 ± 2.8% (mean ±s.e.m., n = 7) compared with control pipette solution, whereas with 1.5 mm BAPTA, the mean EPSP amplitude was reduced by 72 ± 1.5% (n = 5). The concentration of BAPTA that reduced mean EPSP amplitudes to one-half of control was close to 0.7 mm. Saturation of BAPTA during evoked release was tested by comparing the effect of loading the presynaptic neurone with 0.1 mm BAPTA at 2 and 1 mm[Ca2+]o. Reducing [Ca2+]o from 2 to 1 mm, thereby reducing Ca2+ influx into the terminals, decreased the mean EPSP amplitude by 60 ± 2.2% with control pipette solution and by 62 ± 1.9% after loading with 0.1 mm BAPTA (n = 7). The slow Ca2+ buffer EGTA at 1 mm reduced mean EPSP amplitudes by 15 ± 2.5% (n = 5). With 10 mm EGTA mean EPSP amplitudes were reduced by 56 ± 2.3% (n = 4). With both Ca2+ buffers, the reduction in mean EPSP amplitudes was associated with an increase in the c.v. of peak EPSP amplitudes, consistent with a reduction of the transmitter release probability as the major mechanism underlying the reduction of the EPSP amplitude. The results suggest that in nerve terminals of thick tufted L5 pyramidal cells the endogenous mobile Ca2+ buffer is equivalent to less than 0.1 mm BAPTA and that at many release sites of pyramidal cell terminals the Ca2+ channel domains overlap, a situation comparable with that at large calyx-type terminals in the brainstem. PMID:9782165

47 CFR 74.461 - Transmitter power.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Transmitter power. 74.461 Section 74.461....461 Transmitter power. (a) Transmitter power is the power at the transmitter output terminals and.... For the purpose of this Subpart, the transmitter power is the carrier power. (b) The authorized...

47 CFR 74.461 - Transmitter power.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false Transmitter power. 74.461 Section 74.461....461 Transmitter power. (a) Transmitter power is the power at the transmitter output terminals and.... For the purpose of this Subpart, the transmitter power is the carrier power. (b) The authorized...

Quantal and Nonquantal Transmission in Calyx-Bearing Fibers of the Turtle Posterior Crista

PubMed Central

Holt, Joseph C.; Chatlani, Shilpa; Lysakowski, Anna; Goldberg, Jay M.

2010-01-01

Intracellular recordings were made from nerve fibers in the posterior ampullary nerve near the neuroepithelium. Calyx-bearing afferents were identified by their distinctive efferent-mediated responses. Such fibers receive inputs from both type I and type II hair cells. Type II inputs are made by synapses on the outer face of the calyx ending and on the boutons of dimorphic fibers. Quantal activity, consisting of brief mEPSPs, is reduced by lowering the external concentration of Ca2+ and blocked by the AMPA-receptor antagonist CNQX. Poisson statistics govern the timing of mEPSPs, which occur at high rates (250–2,500/s) in the absence of mechanical stimulation. Excitation produced by canal-duct indentation can increase mEPSP rates to nearly 5,000/s. As the rate increases, mEPSPs can change from a monophasic depolarization to a biphasic depolarizing– hyperpolarizing sequence, both of whose components are blocked by CNQX. Blockers of voltage-gated currents affect mEPSP size, which is decreased by TTX and is increased by linopirdine. mEPSP size decreases several fold after impalement. The size decrease, although it may be triggered by the depolarization occurring during impalement, persists even at hyperpolarized membrane potentials. Nonquantal transmission is indicated by shot-noise calculations and by the presence of voltage modulations after quantal activity is abolished pharmacologically. An ultrastructural study shows that inner-face inputs from type I hair cells outnumber outer-face inputs from type II hair cells by an almost 6:1 ratio. PMID:17596419

Comparing the survival rate of juvenile Chinook salmon migrating through hydropower systems using injectable and surgical acoustic transmitters

DOE PAGES

Deng, Zhiqun D.; Martinez, J. J.; Li, H.; ...

2017-02-21

Acoustic telemetry is one of the primary technologies for studying the behavior and survival of fishes throughout the world. The size and performance of the transmitters is still the key limiting factor despite that considerable effort has been expended to understand the biological effects of implantation of acoustic transmitters in yearling and subyearling Chinook salmon. The newly developed injectable transmitter is the first active acoustic tag that can be implanted via injection instead of surgery. It also lasts more than four times longer than the commercially-available transmitters. A two-part field study was conducted to evaluate the performance of the injectablemore » transmitter and its effect on the survival of implanted fish. The injectable transmitter performed well and similarly to the other commercially-available transmitters tested. Snake River subyearling Chinook salmon smolts implanted with the injectable tag had a higher survival probability from release to each of 11 downstream detection arrays than concurrent releases of fish surgically implanted with commercially-available tags. In addition, reach-specific survival estimates were significantly higher for the injectable group in three of the eleven reaches examined. Overall, the injectable group had a 0.263 (SE = 0.017) survival probability over the entire 500 km study area compared to 0.199 (0.012) for the surgically implanted group. The differences in survival may have been caused by warm water temperatures and higher rates of infection experienced by the surgically implanted group due to the presence of sutures acting as an attachment site for pathogens. The reduction in size and ability to implant the new transmitter via injection has further reduced the tag or tagging effect bias associated with studying small fishes. As a result, the information gathered with this new technology is helping minimize the impact of dams on fish, leading to more environmentally sustainable energy systems.« less

Comparing the survival rate of juvenile Chinook salmon migrating through hydropower systems using injectable and surgical acoustic transmitters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Zhiqun D.; Martinez, J. J.; Li, H.

Acoustic telemetry is one of the primary technologies for studying the behavior and survival of fishes throughout the world. The size and performance of the transmitters is still the key limiting factor despite that considerable effort has been expended to understand the biological effects of implantation of acoustic transmitters in yearling and subyearling Chinook salmon. The newly developed injectable transmitter is the first active acoustic tag that can be implanted via injection instead of surgery. It also lasts more than four times longer than the commercially-available transmitters. A two-part field study was conducted to evaluate the performance of the injectablemore » transmitter and its effect on the survival of implanted fish. The injectable transmitter performed well and similarly to the other commercially-available transmitters tested. Snake River subyearling Chinook salmon smolts implanted with the injectable tag had a higher survival probability from release to each of 11 downstream detection arrays than concurrent releases of fish surgically implanted with commercially-available tags. In addition, reach-specific survival estimates were significantly higher for the injectable group in three of the eleven reaches examined. Overall, the injectable group had a 0.263 (SE = 0.017) survival probability over the entire 500 km study area compared to 0.199 (0.012) for the surgically implanted group. The differences in survival may have been caused by warm water temperatures and higher rates of infection experienced by the surgically implanted group due to the presence of sutures acting as an attachment site for pathogens. The reduction in size and ability to implant the new transmitter via injection has further reduced the tag or tagging effect bias associated with studying small fishes. As a result, the information gathered with this new technology is helping minimize the impact of dams on fish, leading to more environmentally sustainable energy systems.« less

The 10 micrometer transmitter

NASA Technical Reports Server (NTRS)

1976-01-01

The design, fabrication tests, and engineering model components of a 10.6 mum wideband transceiver system are reported. The effort emphasized the transmitter subsystem, including the development of the laser, the modulator driver, and included productization of both the transmitter and local oscillator lasers. The transmitter subsystem is functionally compatible with the receiver engineering model terminal, and has undergone high data rate communication system testing against that terminal.

Somatodendritic dopamine release: recent mechanistic insights

PubMed Central

Rice, Margaret E.; Patel, Jyoti C.

2015-01-01

Dopamine (DA) is a key transmitter in motor, reward and cogitative pathways, with DA dysfunction implicated in disorders including Parkinson's disease and addiction. Located in midbrain, DA neurons of the substantia nigra pars compacta project via the medial forebrain bundle to the dorsal striatum (caudate putamen), and DA neurons in the adjacent ventral tegmental area project to the ventral striatum (nucleus accumbens) and prefrontal cortex. In addition to classical vesicular release from axons, midbrain DA neurons exhibit DA release from their cell bodies and dendrites. Somatodendritic DA release leads to activation of D2 DA autoreceptors on DA neurons that inhibit their firing via G-protein-coupled inwardly rectifying K+ channels. This helps determine patterns of DA signalling at distant axonal release sites. Somatodendritically released DA also acts via volume transmission to extrasynaptic receptors that modulate local transmitter release and neuronal activity in the midbrain. Thus, somatodendritic release is a pivotal intrinsic feature of DA neurons that must be well defined in order to fully understand the physiology and pathophysiology of DA pathways. Here, we review recent mechanistic aspects of somatodendritic DA release, with particular emphasis on the Ca2+ dependence of release and the potential role of exocytotic proteins. PMID:26009764

47 CFR 22.625 - Transmitter locations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Transmitter locations. 22.625 Section 22.625... Paging and Radiotelephone Service Point-To-Multipoint Operation § 22.625 Transmitter locations. This... channels will occur. (1) Control transmitter locations. Control transmitter locations must be within 80...

47 CFR 80.959 - Radiotelephone transmitter.

Code of Federal Regulations, 2010 CFR

2010-10-01

... watts into 50 ohms nominal resistance when operated with its rated supply voltage. The transmitter must... capability of the transmitter, measurements of primary supply voltage and transmitter output power must be... voltage measured at the power input terminals to the transmitter terminated in a matching artificial load...

Role of external and internal calcium on heterocarrier-mediated transmitter release.

PubMed

Fassio, A; Bonanno, G; Fontana, G; Usai, C; Marchi, M; Raiteri, M

1996-04-01

Release-regulating heterocarriers exist on brain nerve endings. We have investigated in this study the mechanisms involved in the neurotransmitter release evoked by GABA heterocarrier activation. GABA increased the basal release of [3H]acetylcholine and [3H]noradrenaline from rat hippocampal synaptosomes and of [3H]dopamine from striatal synaptosomes. These GABA effects, insensitive to GABA receptor antagonists, were prevented by inhibiting GABA uptake but not by blocking noradrenaline, choline, or dopamine transport. Lack of extracellular Ca2+ or addition of tetrodotoxin selectively abolished the GABA-evoked release of [3H]noradrenaline, leaving unaffected that of [3H]acetylcholine or [3H]dopamine. 1,2-Bis(2-aminophenoxyl)-ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM) or vesamicol attenuated the release of [3H]acetylcholine elicited by GABA. Reserpine, but not BAPTA-AM, prevented the effect of GABA on [3H] dopamine release. Autoreceptor activation inhibited the GABA-evoked release of [3H]noradrenaline but not that of [3H]acetylcholine or [3H]dopamine. It is concluded that (a) the release of [3H]noradrenaline consequent to activation of GABA heterocarriers sited on noradrenergic terminals meets the criteria of a conventional exocytotic process, (b) the extracellular [Ca2+]-independent releases of [3H]acetylcholine and [3H]dopamine appear to occur from vesicles possibly through involvement of intraterminal Ca2+, and (c) autoreceptor activation only affects heterocarrier-mediated vesicular release linked to entry of extracellular Ca2+.

Comparing the survival rate of juvenile Chinook salmon migrating through hydropower systems using injectable and surgical acoustic transmitters

PubMed Central

Deng, Z. D.; Martinez, J. J.; Li, H.; Harnish, R. A.; Woodley, C. M.; Hughes, J. A.; Li, X.; Fu, T.; Lu, J.; McMichael, G. A.; Weiland, M. A.; Eppard, M. B.; Skalski, J. R.; Townsend, R. L.

2017-01-01

Acoustic telemetry is one of the primary technologies for studying the behavior and survival of fishes throughout the world. The size and performance of the transmitter are key limiting factors. The newly developed injectable transmitter is the first acoustic transmitter that can be implanted via injection instead of surgery. A two-part field study was conducted to evaluate the performance of the injectable transmitter and its effect on the survival of implanted fish. The injectable transmitter performed well and similarly to the proceeding generation of commercially-available JSATS transmitters tested concurrently. Snake River subyearling Chinook salmon smolts implanted with the injectable transmitter had a higher survival probability from release to each of eleven downstream detection arrays, because reach-specific survival estimates were significantly higher for the injectable group in three of the eleven reaches examined. Overall, the injectable group had a 0.263 (SE = 0.017) survival probability over the entire 500 km study area compared to 0.199 (0.012) for the surgically implanted group. The reduction in size and ability to implant the new transmitter via injection has reduced the tag or tagging effect bias associated with studying small fishes. The information gathered with this new technology is helping to evaluate the impacts of dams on fishes. PMID:28220850

Comparing the survival rate of juvenile Chinook salmon migrating through hydropower systems using injectable and surgical acoustic transmitters.

PubMed

Deng, Z D; Martinez, J J; Li, H; Harnish, R A; Woodley, C M; Hughes, J A; Li, X; Fu, T; Lu, J; McMichael, G A; Weiland, M A; Eppard, M B; Skalski, J R; Townsend, R L

2017-02-21

Acoustic telemetry is one of the primary technologies for studying the behavior and survival of fishes throughout the world. The size and performance of the transmitter are key limiting factors. The newly developed injectable transmitter is the first acoustic transmitter that can be implanted via injection instead of surgery. A two-part field study was conducted to evaluate the performance of the injectable transmitter and its effect on the survival of implanted fish. The injectable transmitter performed well and similarly to the proceeding generation of commercially-available JSATS transmitters tested concurrently. Snake River subyearling Chinook salmon smolts implanted with the injectable transmitter had a higher survival probability from release to each of eleven downstream detection arrays, because reach-specific survival estimates were significantly higher for the injectable group in three of the eleven reaches examined. Overall, the injectable group had a 0.263 (SE = 0.017) survival probability over the entire 500 km study area compared to 0.199 (0.012) for the surgically implanted group. The reduction in size and ability to implant the new transmitter via injection has reduced the tag or tagging effect bias associated with studying small fishes. The information gathered with this new technology is helping to evaluate the impacts of dams on fishes.

Comparing the survival rate of juvenile Chinook salmon migrating through hydropower systems using injectable and surgical acoustic transmitters

NASA Astrophysics Data System (ADS)

Deng, Z. D.; Martinez, J. J.; Li, H.; Harnish, R. A.; Woodley, C. M.; Hughes, J. A.; Li, X.; Fu, T.; Lu, J.; McMichael, G. A.; Weiland, M. A.; Eppard, M. B.; Skalski, J. R.; Townsend, R. L.

2017-02-01

Acoustic telemetry is one of the primary technologies for studying the behavior and survival of fishes throughout the world. The size and performance of the transmitter are key limiting factors. The newly developed injectable transmitter is the first acoustic transmitter that can be implanted via injection instead of surgery. A two-part field study was conducted to evaluate the performance of the injectable transmitter and its effect on the survival of implanted fish. The injectable transmitter performed well and similarly to the proceeding generation of commercially-available JSATS transmitters tested concurrently. Snake River subyearling Chinook salmon smolts implanted with the injectable transmitter had a higher survival probability from release to each of eleven downstream detection arrays, because reach-specific survival estimates were significantly higher for the injectable group in three of the eleven reaches examined. Overall, the injectable group had a 0.263 (SE = 0.017) survival probability over the entire 500 km study area compared to 0.199 (0.012) for the surgically implanted group. The reduction in size and ability to implant the new transmitter via injection has reduced the tag or tagging effect bias associated with studying small fishes. The information gathered with this new technology is helping to evaluate the impacts of dams on fishes.

Dendritic release of neurotransmitters

PubMed Central

Ludwig, Mike; Apps, David; Menzies, John; Patel, Jyoti C.; Rice, Margaret E.

2017-01-01

Release of neuroactive substances by exocytosis from dendrites is surprisingly widespread and is not confined to a particular class of transmitters: it occurs in multiple brain regions, and includes a range of neuropeptides, classical neurotransmitters and signaling molecules such as nitric oxide, carbon monoxide, ATP and arachidonic acid. This review is focused on hypothalamic neuroendocrine cells that release vasopressin and oxytocin and midbrain neurons that release dopamine. For these two model systems, the stimuli, mechanisms and physiological functions of dendritic release have been explored in greater detail than is yet available for other neurons and neuroactive substances. PMID:28135005

Biophysical and Biochemical Mechanisms in Synaptic Transmitter Release.

DTIC Science & Technology

1992-01-31

vesicle is normally released per active zone Sci USA 83. 3032 (1986) pared (15, 19, 20). In fact, in squid, the quantum 8 0 Shimomura 8 Musicki. V Kisni...8217, AND R. LLINAS• *Instituto de Biologia Celular Facultad de Medicina. Universidad de Buenos Aires. Paraguay 2155. Buenos Aires 1121. Argentina: and

Spacecraft transmitter reliability

NASA Technical Reports Server (NTRS)

1980-01-01

A workshop on spacecraft transmitter reliability was held at the NASA Lewis Research Center on September 25 and 26, 1979, to discuss present knowledge and to plan future research areas. Since formal papers were not submitted, this synopsis was derived from audio tapes of the workshop. The following subjects were covered: users' experience with space transmitters; cathodes; power supplies and interfaces; and specifications and quality assurance. A panel discussion ended the workshop.

The release of acetylcholine from post-ganglionic cell bodies in response to depolarization.

PubMed Central

Johnson, D A; Pilar, G

1980-01-01

1. Acetylcholine (Ach) release from parasympathetic ganglia cell somata was investigated in denervated avian ciliary ganglia. Three days after the input to the ganglion (the oculomotor nerve) was sectioned, all presynaptic nerve terminals had degenerated. 2. Denervated ganglia were shown to contain endogenous ACh and to be capable of synthesizing [3H]ACh from [3H]choline added to the incubation medium. 3. In response to depolarization induced by incubation in 50 mM-[K+]o, denervated ganglia released [3H]ACh into bath effluents in amounts approximately 15% of the non-denervated contralateral control. This release was shown to be Ca2+ dependent in both intact and denervated ganglia. 4. Antidromic electrical stimulation of ciliary nerves also elicited [3H]ACh release. Nicotine (1 microgram/microliter.) depolarized denervated ciliary ganglion cells and evoked release of the transmitter and this release was antagonized by curare. 5. It is concluded that the ganglionic cell bodies sysnthesized ACh and released the transmitter in response to K+ depolarization, antidromic stimulation and cholinergic agonists, despite the lack of morphological specializations usually associated with stimulus-induced release of neurotransmitter. The evidence suggests the existence of a mechanism of transmitter release which is Ca2+ dependent, probably from a cytoplasmic pool and therefore distinct from the usual vesicular release at the nerve terminal. Images Plate 1 Plate 2 PMID:6247485

Spike-independent release of ATP from Xenopus spinal neurons evoked by activation of glutamate receptors

PubMed Central

Brown, Paul; Dale, Nicholas

2002-01-01

As the release of ATP from neurons has only been directly studied in a few cases, we have used patch sniffing to examine ATP release from Xenopus spinal neurons. ATP release was detected following intracellular current injection to evoke spikes. However, spiking was not essential as both glutamate and NMDA could evoke release of ATP in the presence of TTX. Neither acetylcholine nor high K+ was effective at inducing ATP release in the presence of TTX. Although Cd2+ blocked glutamate-evoked release of ATP suggesting a dependence on Ca2+ entry, neither ω-conotoxin-GVIA nor nifedipine prevented ATP release. N-type and L-type channels are thus not essential for glutamate-evoked ATP release. That glutamate receptors can elicit release in the absence of spiking suggests a close physical relationship between these receptors, the Ca2+ channels and release sites. As the dependence of ATP release on the influx of Ca2+ through Ca2+ channel subtypes differs from that of synaptic transmitter release, ATP may be released from sites that are distinct from those of the principal transmitter. In addition to its role as a fast transmitter, ATP may thus be released as a consequence of the activation of excitatory glutamatergic synapses and act to signal information about activity patterns in the nervous system. PMID:11986374

Mimicking Neurotransmitter Release in Chemical Synapses via Hysteresis Engineering in MoS2 Transistors.

PubMed

Arnold, Andrew J; Razavieh, Ali; Nasr, Joseph R; Schulman, Daniel S; Eichfeld, Chad M; Das, Saptarshi

2017-03-28

Neurotransmitter release in chemical synapses is fundamental to diverse brain functions such as motor action, learning, cognition, emotion, perception, and consciousness. Moreover, improper functioning or abnormal release of neurotransmitter is associated with numerous neurological disorders such as epilepsy, sclerosis, schizophrenia, Alzheimer's disease, and Parkinson's disease. We have utilized hysteresis engineering in a back-gated MoS 2 field effect transistor (FET) in order to mimic such neurotransmitter release dynamics in chemical synapses. All three essential features, i.e., quantal, stochastic, and excitatory or inhibitory nature of neurotransmitter release, were accurately captured in our experimental demonstration. We also mimicked an important phenomenon called long-term potentiation (LTP), which forms the basis of human memory. Finally, we demonstrated how to engineer the LTP time by operating the MoS 2 FET in different regimes. Our findings could provide a critical component toward the design of next-generation smart and intelligent human-like machines and human-machine interfaces.

47 CFR 101.513 - Transmitter power.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transmitter power. 101.513 Section 101.513... SERVICES 24 GHz Service and Digital Electronic Message Service § 101.513 Transmitter power. The transmitter power will be governed by § 101.113. Further, each application must contain an analysis demonstrating...

47 CFR 101.513 - Transmitter power.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Transmitter power. 101.513 Section 101.513... SERVICES 24 GHz Service and Digital Electronic Message Service § 101.513 Transmitter power. The transmitter power will be governed by § 101.113. Further, each application must contain an analysis demonstrating...

Neurotransmitter release.

PubMed

Süudhof, Thomas C

2008-01-01

Neurons send out a multitude of chemical signals, called neurotransmitters, to communicate between neurons in brain, and between neurons and target cells in the periphery. The most important of these communication processes is synaptic transmission, which accounts for the ability of the brain to rapidly process information, and which is characterized by the fast and localized transfer of a signal from a presynaptic neuron to a postsynaptic cell. Other communication processes, such as the modulation of the neuronal state in entire brain regions by neuromodulators, provide an essential component of this information processing capacity. A large number of diverse neurotransmitters are used by neurons, ranging from classical fast transmitters such as glycine and glutamate over neuropeptides to lipophilic compounds and gases such as endocannabinoids and nitric oxide. Most of these transmitters are released by exocytosis, the i.e. the fusion of secretory vesicles with the plasma membrane, which exhibits distinct properties for different types of neurotransmitters. The present chapter will provide an overview of the process of neurotransmitter release and its historical context, and give a reference point for the other chapters in this book.

Knocking out P2X receptors reduces transmitter secretion in taste buds.

PubMed

Huang, Yijen A; Stone, Leslie M; Pereira, Elizabeth; Yang, Ruibiao; Kinnamon, John C; Dvoryanchikov, Gennady; Chaudhari, Nirupa; Finger, Thomas E; Kinnamon, Sue C; Roper, Stephen D

2011-09-21

In response to gustatory stimulation, taste bud cells release a transmitter, ATP, that activates P2X2 and P2X3 receptors on gustatory afferent fibers. Taste behavior and gustatory neural responses are largely abolished in mice lacking P2X2 and P2X3 receptors [P2X2 and P2X3 double knock-out (DKO) mice]. The assumption has been that eliminating P2X2 and P2X3 receptors only removes postsynaptic targets but that transmitter secretion in mice is normal. Using functional imaging, ATP biosensor cells, and a cell-free assay for ATP, we tested this assumption. Surprisingly, although gustatory stimulation mobilizes Ca(2+) in taste Receptor (Type II) cells from DKO mice, as from wild-type (WT) mice, taste cells from DKO mice fail to release ATP when stimulated with tastants. ATP release could be elicited by depolarizing DKO Receptor cells with KCl, suggesting that ATP-release machinery remains functional in DKO taste buds. To explore the difference in ATP release across genotypes, we used reverse transcriptase (RT)-PCR, immunostaining, and histochemistry for key proteins underlying ATP secretion and degradation: Pannexin1, TRPM5, and NTPDase2 (ecto-ATPase) are indistinguishable between WT and DKO mice. The ultrastructure of contacts between taste cells and nerve fibers is also normal in the DKO mice. Finally, quantitative RT-PCR show that P2X4 and P2X7, potential modulators of ATP secretion, are similarly expressed in taste buds in WT and DKO taste buds. Importantly, we find that P2X2 is expressed in WT taste buds and appears to function as an autocrine, positive feedback signal to amplify taste-evoked ATP secretion.

Knocking out P2X receptors reduces transmitter secretion in taste buds

PubMed Central

Huang, Yijen A.; Stone, Leslie M.; Pereira, Elizabeth; Yang, Ruibiao; Kinnamon, John C.; Dvoryanchikov, Gennady; Chaudhari, Nirupa; Finger, Thomas E.; Kinnamon, Sue C.; Roper, Stephen D.

2011-01-01

In response to gustatory stimulation, taste bud cells release a transmitter, ATP, that activates P2X2 and P2X3 receptors on gustatory afferent fibers. Taste behavior and gustatory neural responses are largely abolished in mice lacking P2X2 and P2X3 receptors (P2X2 and P2X3 double knockout, or “DKO” mice). The assumption has been that eliminating P2X2 and P2X3 receptors only removes postsynaptic targets but that transmitter secretion in mice is normal. Using functional imaging, ATP biosensor cells, and a cell-free assay for ATP, we tested this assumption. Surprisingly, although gustatory stimulation mobilizes Ca2+ in taste Receptor (Type II) cells from DKO mice, as from wild type (WT) mice, taste cells from DKO mice fail to release ATP when stimulated with tastants. ATP release could be elicited by depolarizing DKO Receptor cells with KCl, suggesting that ATP-release machinery remains functional in DKO taste buds. To explore the difference in ATP release across genotypes, we employed reverse transcriptase (RT)-PCR, immunostaining, and histochemistry for key proteins underlying ATP secretion and degradation: Pannexin1, TRPM5, and NTPDase2 (ecto-ATPase) are indistinguishable between WT and DKO mice. The ultrastructure of contacts between taste cells and nerve fibers is also normal in the DKO mice. Finally, quantitative RT-PCR show that P2X4 and P2X7, potential modulators of ATP secretion, are similarly expressed in taste buds in WT and DKO taste buds. Importantly, we find that P2X2 is expressed in WT taste buds and appears to function as an autocrine, positive feedback signal to amplify taste-evoked ATP secretion. PMID:21940456

Transionospheric Propagation of VLF Transmitter Signals

NASA Astrophysics Data System (ADS)

Cohen, M.; Inan, U. S.; Lehtinen, N. G.

2012-12-01

Ground based Very Low Frequency (VLF, 3-30 kHz) radio transmitters may play a significant role in precipitation of inner belt (L<2.5) energetic Van Allen electrons. Initial analyses of the total contribution of VLF transmitters utilized models of transionospheric propagation, but some recent studies have suggested that those models may overestimate (by 20-100 dB) the VLF energy reaching the magnetosphere. One possible cause of this discrepancy was suggested to be conversion of wave energy into electrostatic modes in the D, E, and F regions, from ionospheric density irregularities, either natural or generated by the transmitter heating itself. The DEMETER satellite built a six year history of continuous and global survey mode data which, when combined, yields detailed pictures of the radiation pattern from many transmitters into space at 680 km, with 25 km resolution, and clear features like the interference pattern on the ground mapped upwards. With both E and B survey mode data, we can also directly approximate the total power injected into the magnetosphere from each transmitter, separately for day and night, as well as the power arriving at the conjugate region. We find no detectable variation of signal intensity with geomagnetic conditions. We find evidence of transmitter heating affecting the transionospheric propagation of other transmitters. We find that the power reaching the conjugate region is a large fraction of the power injected above the transmitter. We then employ a full wave model to simulate VLF transmitter transionospheric propagation, calculating the electromagnetic fields and power flux injected into the magnetosphere. Although the model does not include ionospheric irregularities, the radiation pattern largely matches the observed one, and the total power calculated is within 6 dB of observations for every transmitter, both day and night, and across a range of low to middle latitudes and transmitter powers. We thus conclude that the effect of

Short-term survival and effects of transmitter implantation into western grebes using a modified surgical procedure

USGS Publications Warehouse

Gaydos, Joseph K.; Massey, J. Gregory; Mulcahy, Daniel M.; Gaskins, Lori A.; Nysewander, David; Evenson, Joseph; Siegel, Paul B.; Ziccardi, Michael H.

2011-01-01

intracelomically implanted with transmitters with percutaneous antennae and released into the wild.

A Phenomenological Synapse Model for Asynchronous Neurotransmitter Release

PubMed Central

Wang, Tao; Yin, Luping; Zou, Xiaolong; Shu, Yousheng; Rasch, Malte J.; Wu, Si

2016-01-01

Neurons communicate with each other via synapses. Action potentials cause release of neurotransmitters at the axon terminal. Typically, this neurotransmitter release is tightly time-locked to the arrival of an action potential and is thus called synchronous release. However, neurotransmitter release is stochastic and the rate of release of small quanta of neurotransmitters can be considerably elevated even long after the ceasing of spiking activity, leading to asynchronous release of neurotransmitters. Such asynchronous release varies for tissue and neuron types and has been shown recently to be pronounced in fast-spiking neurons. Notably, it was found that asynchronous release is enhanced in human epileptic tissue implicating a possibly important role in generating abnormal neural activity. Current neural network models for simulating and studying neural activity virtually only consider synchronous release and ignore asynchronous transmitter release. Here, we develop a phenomenological model for asynchronous neurotransmitter release, which, on one hand, captures the fundamental features of the asynchronous release process, and, on the other hand, is simple enough to be incorporated in large-size network simulations. Our proposed model is based on the well-known equations for short-term dynamical synaptic interactions and includes an additional stochastic term for modeling asynchronous release. We use experimental data obtained from inhibitory fast-spiking synapses of human epileptic tissue to fit the model parameters, and demonstrate that our model reproduces the characteristics of realistic asynchronous transmitter release. PMID:26834617

Evaluation of the performance of spectacle lens "transmittance meters".

PubMed

Stephens, G L; Pitts, D G

1994-03-01

Inexpensive transmittance meters have recently been developed for measuring of mean ultraviolet (UV) radiant transmittance and luminous transmittance of spectacle lenses. Our purpose was to determine how accurately these meters measured transmittance. The mean UV transmittance and the luminous transmittance of a series of lenses were determined using a spectrophotometer. Transmittance meters were then used to measure the same lenses. In general, the meters overestimated total (mean) UV transmittance. Luminous transmittance was relatively accurately measured by those meters which had this capability. Although the meters do not measure UV transmittance accurately, they are still useful for determining if a lens transmits any UV radiation. The relatively narrow response range of the meters, centered at 360 to 380 nm, is responsible for the measurement error of mean UV transmittance.

Modeling and measurement of vesicle pools at the cone ribbon synapse: changes in release probability are solely responsible for voltage-dependent changes in release

PubMed Central

Thoreson, Wallace B.; Van Hook, Matthew J.; Parmelee, Caitlyn; Curto, Carina

2015-01-01

Post-synaptic responses are a product of quantal amplitude (Q), size of the releasable vesicle pool (N), and release probability (P). Voltage-dependent changes in presynaptic Ca2+ entry alter post-synaptic responses primarily by changing P but have also been shown to influence N. With simultaneous whole cell recordings from cone photoreceptors and horizontal cells in tiger salamander retinal slices, we measured N and P at cone ribbon synapses by using a train of depolarizing pulses to stimulate release and deplete the pool. We developed an analytical model that calculates the total pool size contributing to release under different stimulus conditions by taking into account the prior history of release and empirically-determined properties of replenishment. The model provided a formula that calculates vesicle pool size from measurements of the initial post-synaptic response and limiting rate of release evoked by a train of pulses, the fraction of release sites available for replenishment, and the time constant for replenishment. Results of the model showed that weak and strong depolarizing stimuli evoked release with differing probabilities but the same size vesicle pool. Enhancing intraterminal Ca2+ spread by lowering Ca2+ buffering or applying BayK8644 did not increase PSCs evoked with strong test steps showing there is a fixed upper limit to pool size. Together, these results suggest that light-evoked changes in cone membrane potential alter synaptic release solely by changing release probability. PMID:26541100

Mortality, Transmitter Retention, Growth, and Wound Healing in Juvenile Salmon Injected with Micro Acoustic Transmitters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liss, Stephanie A.; Brown, Richard S.; Deters, Katherine A.

A cylindrical acoustic transmitter (AT; 0.2 g) has been developed for injection into the peritoneum of fish. Laboratory studies can provide tagging guidelines to minimize the effect of implantation techniques and transmitter burden (relative weight of the transmitter to the weight of the fish) in fish before a transmitter is used in field studies. The goal of this study was to examine response variables (mortality, transmitter expulsion, growth, wound area) of juvenile Chinook Salmon (Oncorhynchus tschawytscha; 65–104 mm fork length [FL]) injected with an AT along a wide range of sizes that could lead to a guideline for minimizing taggingmore » effects. The overarching goal was to determine a minimum size threshold for fish that can be injected, while minimizing adverse transmitter effects. Juveniles (n = 700) were separated into four treatments: (1) acoustic transmitter injection (AT), (2) AT and a passive integrated transponder tag injection (AT+PIT), (3) visual implant elastomer injection (Marked control), and (4) unmarked (Unmarked control). Fish were evaluated weekly for four weeks, and again at the end of the study (60 d post-tagging). Fish injected with an AT or an AT+PIT experienced greater mortality than Marked controls. By 60 d post-tagging, transmitter expulsion was 44% for AT fish and 20% for AT+PIT fish. Fish injected with an AT or an AT+PIT grew (FL and weight gain) significantly less than Marked controls, and no minimum size thresholds were detected. Finally, initial size (FL) significantly affected wound area in AT and AT+PIT fish. A size threshold was only identified on Day 7 (85.1 mm) for AT+PIT fish, indicating that wound areas in fish < 85.1 mm were larger than wound areas of fish > 85.1 mm. This research suggests that injecting juveniles with an AT or an AT+PIT had a greater effect on smaller fish than larger fish.« less

A Low Cost TDRSS Compatible Transmitter Option

NASA Technical Reports Server (NTRS)

Whiteman, Don

2005-01-01

The NASA Space-based Telemetry and Range Safety (STARS) program has developed and tested a low cost Ku-Band transmitter alternative for TDRSS applications based on an existing IRIG shaped offset quaternary phase shift keying (SOQPSK) transmitter. This paper presents information related to the implementation of this low cost system, as well as performance measurements of the alternative TDRSS transmitter system compared with an existing QPSK TDRSS transmitter.

Quantum aspects of brain activity and the role of consciousness.

PubMed Central

Beck, F; Eccles, J C

1992-01-01

The relationship of brain activity to conscious intentions is considered on the basis of the functional microstructure of the cerebral cortex. Each incoming nerve impulse causes the emission of transmitter molecules by the process of exocytosis. Since exocytosis is a quantal phenomenon of the presynaptic vesicular grid with a probability much less than 1, we present a quantum mechanical model for it based on a tunneling process of the trigger mechanism. Consciousness manifests itself in mental intentions. The consequent voluntary actions become effective by momentary increases of the probability of vesicular emission in the thousands of synapses on each pyramidal cell by quantal selection. PMID:1333607

Automatic frequency control for FM transmitter

NASA Technical Reports Server (NTRS)

Honnell, M. A. (Inventor)

1974-01-01

An automatic frequency control circuit for an FM television transmitter is described. The frequency of the transmitter is sampled during what is termed the back porch portion of the horizontal synchronizing pulse which occurs during the retrace interval, the frequency sample compared with the frequency of a reference oscillator, and a correction applied to the frequency of the transmitter during this portion of the retrace interval.

Borehole induction coil transmitter

DOEpatents

Holladay, Gale; Wilt, Michael J.

2002-01-01

A borehole induction coil transmitter which is a part of a cross-borehole electromagnetic field system that is used for underground imaging applications. The transmitter consists of four major parts: 1) a wound ferrite or mu-metal core, 2) an array of tuning capacitors, 3) a current driver circuit board, and 4) a flux monitor. The core is wound with several hundred turns of wire and connected in series with the capacitor array, to produce a tuned coil. This tuned coil uses internal circuitry to generate sinusoidal signals that are transmitted through the earth to a receiver coil in another borehole. The transmitter can operate at frequencies from 1-200 kHz and supplies sufficient power to permit the field system to operate in boreholes separated by up to 400 meters.

47 CFR 73.315 - FM transmitter location.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false FM transmitter location. 73.315 Section 73.315 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES FM Broadcast Stations § 73.315 FM transmitter location. (a) The transmitter location shall be chosen so that...

47 CFR 73.315 - FM transmitter location.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false FM transmitter location. 73.315 Section 73.315 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES FM Broadcast Stations § 73.315 FM transmitter location. (a) The transmitter location shall be chosen so that...

Laser Transmitter Aims At Laser Beacon

NASA Technical Reports Server (NTRS)

Hemmati, Hamid; Lesh, James R.

1993-01-01

Transmitter part of developmental optical communication system. Compact, lightweight, partially-self-aiming laser transmitter built to verify some capabilities of developmental free-space optical communication system. Design capable of providing 0.5 Mbps data return over range equal to Moon-Earth distance. Breadboard of transmitting terminal constructed and tested in laboratory. Prototype transmitter includes receiving circuitry that keeps it aimed at beacon, once brought into initial alignment within about 1.7 degrees of line of sight to beacon.

New Treatments for Drug-Resistant Epilepsy that Target Presynaptic Transmitter Release

DTIC Science & Technology

2013-05-01

induced status epilepticus persistently increases size, vesicular release rate and endocytosis of mossy fiber boutons in SpH-expressing mice Size... status epilepticus rats We also examined the effects of LEV on miniature excitatory postsynaptic currents (mEPSCs) evoked by spontaneous release...Pilocarpine vs. lithium-pilocarpine for induction of status epilepticus in mice: development of spontaneous seizures, behavioral alterations and

Reserve pool neuron transmitter respecification: Novel neuroplasticity.

PubMed

Dulcis, Davide; Spitzer, Nicholas C

2012-04-01

The identity of the neurotransmitters expressed by neurons has been thought to be fixed and immutable, but recent studies demonstrate that changes in electrical activity can rapidly and reversibly reconfigure the transmitters and corresponding transmitter receptors that neurons express. Induction of transmitter expression can be achieved by selective activation of afferents recruited by a physiological range of sensory input. Strikingly, neurons acquiring an additional transmitter project to appropriate targets prior to transmitter respecification in some cases, indicating the presence of reserve pools of neurons that can boost circuit function. We discuss the evidence for such reserve pools, their likely locations and ways to test for their existence, and the potential clinical value of such circuit-specific neurotransmitter respecification for treatments of neurological disorders. Copyright © 2011 Wiley Periodicals, Inc.

Efficiency of synaptic transmission of single-photon events from rod photoreceptor to rod bipolar dendrite.

PubMed

Schein, Stan; Ahmad, Kareem M

2006-11-01

A rod transmits absorption of a single photon by what appears to be a small reduction in the small number of quanta of neurotransmitter (Q(count)) that it releases within the integration period ( approximately 0.1 s) of a rod bipolar dendrite. Due to the quantal and stochastic nature of release, discrete distributions of Q(count) for darkness versus one isomerization of rhodopsin (R*) overlap. We suggested that release must be regular to narrow these distributions, reduce overlap, reduce the rate of false positives, and increase transmission efficiency (the fraction of R* events that are identified as light). Unsurprisingly, higher quantal release rates (Q(rates)) yield higher efficiencies. Focusing here on the effect of small changes in Q(rate), we find that a slightly higher Q(rate) yields greatly reduced efficiency, due to a necessarily fixed quantal-count threshold. To stabilize efficiency in the face of drift in Q(rate), the dendrite needs to regulate the biochemical realization of its quantal-count threshold with respect to its Q(count). These considerations reveal the mathematical role of calcium-based negative feedback and suggest a helpful role for spontaneous R*. In addition, to stabilize efficiency in the face of drift in degree of regularity, efficiency should be approximately 50%, similar to measurements.

Optogenetic Acidification of Synaptic Vesicles and Lysosomes

PubMed Central

Grauel, M. Katharina; Wozny, Christian; Bentz, Claudia; Blessing, Anja; Rosenmund, Tanja; Jentsch, Thomas J.; Schmitz, Dietmar; Hegemann, Peter; Rosenmund, Christian

2016-01-01

Acidification is required for the function of many intracellular organelles, but methods to acutely manipulate their intraluminal pH have not been available. Here we present a targeting strategy to selectively express the light-driven proton pump Arch3 on synaptic vesicles. Our new tool, pHoenix, can functionally replace endogenous proton pumps, enabling optogenetic control of vesicular acidification and neurotransmitter accumulation. Under physiological conditions, glutamatergic vesicles are nearly full, as additional vesicle acidification with pHoenix only slightly increased the quantal size. By contrast, we found that incompletely filled vesicles exhibited a lower release probability than full vesicles, suggesting preferential exocytosis of vesicles with high transmitter content. Our subcellular targeting approach can be transferred to other organelles, as demonstrated for a pHoenix variant that allows light-activated acidification of lysosomes. PMID:26551543

Optogenetic acidification of synaptic vesicles and lysosomes.

PubMed

Rost, Benjamin R; Schneider, Franziska; Grauel, M Katharina; Wozny, Christian; Bentz, Claudia; Blessing, Anja; Rosenmund, Tanja; Jentsch, Thomas J; Schmitz, Dietmar; Hegemann, Peter; Rosenmund, Christian

2015-12-01

Acidification is required for the function of many intracellular organelles, but methods to acutely manipulate their intraluminal pH have not been available. Here we present a targeting strategy to selectively express the light-driven proton pump Arch3 on synaptic vesicles. Our new tool, pHoenix, can functionally replace endogenous proton pumps, enabling optogenetic control of vesicular acidification and neurotransmitter accumulation. Under physiological conditions, glutamatergic vesicles are nearly full, as additional vesicle acidification with pHoenix only slightly increased the quantal size. By contrast, we found that incompletely filled vesicles exhibited a lower release probability than full vesicles, suggesting preferential exocytosis of vesicles with high transmitter content. Our subcellular targeting approach can be transferred to other organelles, as demonstrated for a pHoenix variant that allows light-activated acidification of lysosomes.

Terrestrial VLF transmitter injection into the magnetosphere

NASA Astrophysics Data System (ADS)

Cohen, M. B.; Inan, U. S.

2012-08-01

Very Low Frequency (VLF, 3-30 kHz) radio waves emitted from ground sources (transmitters and lightning) strongly impact the radiation belts, driving electron precipitation via whistler-electron gyroresonance, and contributing to the formation of the slot region. However, calculations of the global impacts of VLF waves are based on models of trans-ionospheric propagation to calculate the VLF energy reaching the magnetosphere. Limited comparisons of these models to individual satellite passes have found that the models may significantly (by >20 dB) overestimate amplitudes of ground based VLF transmitters in the magnetosphere. To form a much more complete empirical picture of VLF transmitter energy reaching the magnetosphere, we present observations of the radiation pattern from a number of ground-based VLF transmitters by averaging six years of data from the DEMETER satellite. We divide the slice at ˜700 km altitude above a transmitter into pixels and calculate the average field for all satellite passes through each pixel. There are enough data to see 25 km features in the radiation pattern, including the modal interference of the subionospheric signal mapped upwards. Using these data, we deduce the first empirical measure of the radiated power into the magnetosphere from these transmitters, for both daytime and nighttime, and at both the overhead and geomagnetically conjugate region. We find no detectable variation of signal intensity with geomagnetic conditions at low and mid latitudes (L < 2.6). We also present evidence of ionospheric heating by one VLF transmitter which modifies the trans-ionospheric absorption of signals from other transmitters passing through the heated region.

The probability of quantal secretion near a single calcium channel of an active zone.

PubMed Central

Bennett, M R; Farnell, L; Gibson, W G

2000-01-01

A Monte Carlo analysis has been made of calcium dynamics and quantal secretion at microdomains in which the calcium reaches very high concentrations over distances of <50 nm from a channel and for which calcium dynamics are dominated by diffusion. The kinetics of calcium ions in microdomains due to either the spontaneous or evoked opening of a calcium channel, both of which are stochastic events, are described in the presence of endogenous fixed and mobile buffers. Fluctuations in the number of calcium ions within 50 nm of a channel are considerable, with the standard deviation about half the mean. Within 10 nm of a channel these numbers of ions can give rise to calcium concentrations of the order of 100 microM. The temporal changes in free calcium and calcium bound to different affinity indicators in the volume of an entire varicosity or bouton following the opening of a single channel are also determined. A Monte Carlo analysis is also presented of how the dynamics of calcium ions at active zones, after the arrival of an action potential and the stochastic opening of a calcium channel, determine the probability of exocytosis from docked vesicles near the channel. The synaptic vesicles in active zones are found docked in a complex with their calcium-sensor associated proteins and a voltage-sensitive calcium channel, forming a secretory unit. The probability of quantal secretion from an isolated secretory unit has been determined for different distances of an open calcium channel from the calcium sensor within an individual unit: a threefold decrease in the probability of secretion of a quantum occurs with a doubling of the distance from 25 to 50 nm. The Monte Carlo analysis also shows that the probability of secretion of a quantum is most sensitive to the size of the single-channel current compared with its sensitivity to either the binding rates of the sites on the calcium-sensor protein or to the number of these sites that must bind a calcium ion to trigger

APMP Pilot Study on Transmittance Haze

NASA Astrophysics Data System (ADS)

Liu, Wen-Chun; Hwang, Jisoo; Koo, Annette; Wu, Houping; Leecharoen, Rojana; Yu, Hsueh-Ling

2018-02-01

Five NMIs within APMP, including CMS/ITRI, MSL, NIM, NIMT and KRISS from TCPR applied to the APMP technical committee initiative project for funding to carry out a pilot comparison of transmittance haze in 2012. The project started in 2014 and the final report was completed at the end of 2016. In this pilot comparison, three different haze standards were adopted, and transmittance haze for each standard was measured according to ASTM D1003 or ISO 14782. This paper presents the first results of an APMP pilot study of transmittance haze and the analysis of the variation among different haze measurement systems which are commonly used. The study shows that the variables such as sphere multiplier, transmittance distribution, fluorescence of samples and optical path of the incident beam cause discrepancies among NMIs and highlight deficiencies in current documentary standards.

Low Power Transmitter for Wireless Capsule Endoscope

NASA Astrophysics Data System (ADS)

Lioe, D. X.; Shafie, S.; Ramiah, H.; Sulaiman, N.; Halin, I. A.

2013-04-01

This paper presents the transmitter circuit designed for the application of wireless capsule endoscope to overcome the limitation of conventional endoscope. The design is performed using CMOS 0.13 μm technology. The transmitter is designed to operate at centre frequency of 433.92 MHz, which is one of the ISM band. Active mixer and ring oscillator made up the transmitter and it consumes 1.57 mA of current using a supply voltage of 1.2 V, brings the dc power consumption of the transmitter to be 1.88 mW. Data rate of 3.5 Mbps ensure it can transmit high quality medical imaging.

47 CFR 97.313 - Transmitter power standards.

Code of Federal Regulations, 2010 CFR

2010-10-01

... station may transmit with a transmitter power exceeding 1.5 kW PEP. (c) No station may transmit with a transmitter power output exceeding 200 W PEP: (1) On the 10.10-10.15 MHz segment; (2) On the 3.525-3.60 MHz, 7... within ITU Regions 1 or 3. (d) No station may transmit with a transmitter power exceeding 25 W PEP on the...

Inhibition of Ca2+ channels and adrenal catecholamine release by G protein coupled receptors.

PubMed

Currie, Kevin P M

2010-11-01

Catecholamines and other transmitters released from adrenal chromaffin cells play central roles in the "fight-or-flight" response and exert profound effects on cardiovascular, endocrine, immune, and nervous system function. As such, precise regulation of chromaffin cell exocytosis is key to maintaining normal physiological function and appropriate responsiveness to acute stress. Chromaffin cells express a number of different G protein coupled receptors (GPCRs) that sense the local environment and orchestrate this precise control of transmitter release. The primary trigger for catecholamine release is Ca2+ entry through voltage-gated Ca2+ channels, so it makes sense that these channels are subject to complex regulation by GPCRs. In particular G protein βγ heterodimers (Gbc) bind to and inhibit Ca2+ channels. Here I review the mechanisms by which GPCRs inhibit Ca2+ channels in chromaffin cells and how this might be altered by cellular context. This is related to the potent autocrine inhibition of Ca2+ entry and transmitter release seen in chromaffin cells. Recent data that implicate an additional inhibitory target of Gβγ on the exocytotic machinery and how this might fine tune neuroendocrine secretion are also discussed.

Solar radio-transmitters on snail kites in Florida

USGS Publications Warehouse

Snyder, N.F.R.; Beissinger, S.R.; Fuller, M.R.

1989-01-01

The effectiveness and safety of one- and two-stage solar radio-transmitters in tracking the movements and survival of adult and fledgling Snail Kites (Rostrhamus sociabilis) were evaluated between 1979 and 1983 in southern Florida. Transmitters were attached to birds with back-pack arrangements using teflon ribbon straps. Accessory plastic shields minimized feather coverage of the solar cells. Intact transmitters were seen on birds up to 47 mo after installation. Operating lives ranged from 8 to 21 mo for one-stage, and 10 to 14 mo for two-stage transmitters. Because survival of adult and nestling radio-marked kites was high, we conclude that our transmitter-attachment method had little effect on the birds.

Stable, low cost SAW microwave transmitter

NASA Astrophysics Data System (ADS)

Lau, K. F.; Yen, K. H.

1986-06-01

The design flexibility and application possibilities of surface acoustic wave (SAW) technology is discussed. When a highly stable, AM-modulated transmitter is required, a SAW resonator can provide an oscillator Q of up to 20,000 at 1 GHz. When FM modulation is required, the SAW delay line can provide a lower oscillator Q, which represents the optimum tradeoff between frequency stability and FM modulability. The capabilities of SAW oscillators are reviewed, and two example transmitters are presented. One transmitter operates at 1680 MHz and provides an AM-modulated signal. The second operates at the 400 to 406 MHz range and provides an FM-modulated output at one of six frequencies. SAW transmitters are suitable for applications where moderately high stability and low cost are key factors. With direct generation of signals at microwave frequencies and the flexibility of SAW oscillator design, a wide range of performance characteristics can be achieved.

An injectable acoustic transmitter for juvenile salmon

PubMed Central

Deng, Z. D.; Carlson, T. J.; Li, H.; Xiao, J.; Myjak, M. J.; Lu, J.; Martinez, J. J.; Woodley, C. M.; Weiland, M. A.; Eppard, M. B.

2015-01-01

Salmon recovery and the potential detrimental effects of dams on fish have been attracting national attention due to the environmental and economic implications. In recent years acoustic telemetry has been the primary method for studying salmon passage. However, the size of the existing transmitters limits the minimum size of fish that can be studied, introducing a bias to the study results. We developed the first acoustic fish transmitter that can be implanted by injection instead of surgery. The new injectable transmitter lasts four times longer and weighs 30% less than other transmitters. Because the new transmitter costs significantly less to use and may substantially reduce adverse effects of implantation and tag burden, it will allow for study of migration behavior and survival of species and sizes of fish that have never been studied before. The new technology will lead to critical information needed for salmon recovery and the development of fish-friendly hydroelectric systems. PMID:25630763

An injectable acoustic transmitter for juvenile salmon

NASA Astrophysics Data System (ADS)

Deng, Z. D.; Carlson, T. J.; Li, H.; Xiao, J.; Myjak, M. J.; Lu, J.; Martinez, J. J.; Woodley, C. M.; Weiland, M. A.; Eppard, M. B.

2015-01-01

Salmon recovery and the potential detrimental effects of dams on fish have been attracting national attention due to the environmental and economic implications. In recent years acoustic telemetry has been the primary method for studying salmon passage. However, the size of the existing transmitters limits the minimum size of fish that can be studied, introducing a bias to the study results. We developed the first acoustic fish transmitter that can be implanted by injection instead of surgery. The new injectable transmitter lasts four times longer and weighs 30% less than other transmitters. Because the new transmitter costs significantly less to use and may substantially reduce adverse effects of implantation and tag burden, it will allow for study of migration behavior and survival of species and sizes of fish that have never been studied before. The new technology will lead to critical information needed for salmon recovery and the development of fish-friendly hydroelectric systems.

47 CFR 97.313 - Transmitter power standards.

Code of Federal Regulations, 2013 CFR

2013-10-01

... station may transmit with a transmitter power exceeding 1.5 kW PEP. (c) No station may transmit with a transmitter power output exceeding 200 W PEP: (1) On the 10.10-10.15 MHz segment; (2) On the 3.525-3.60 MHz, 7... Regions 1 or 3. (d) No station may transmit with a transmitter power exceeding 25 W PEP on the VHF 1.25 m...

47 CFR 97.313 - Transmitter power standards.

Code of Federal Regulations, 2014 CFR

2014-10-01

... station may transmit with a transmitter power exceeding 1.5 kW PEP. (c) No station may transmit with a transmitter power output exceeding 200 W PEP: (1) On the 10.10-10.15 MHz segment; (2) On the 3.525-3.60 MHz, 7... Regions 1 or 3. (d) No station may transmit with a transmitter power exceeding 25 W PEP on the VHF 1.25 m...

47 CFR 97.313 - Transmitter power standards.

Code of Federal Regulations, 2011 CFR

2011-10-01

... station may transmit with a transmitter power exceeding 1.5 kW PEP. (c) No station may transmit with a transmitter power output exceeding 200 W PEP: (1) On the 10.10-10.15 MHz segment; (2) On the 3.525-3.60 MHz, 7... Regions 1 or 3. (d) No station may transmit with a transmitter power exceeding 25 W PEP on the VHF 1.25 m...

47 CFR 97.313 - Transmitter power standards.

Code of Federal Regulations, 2012 CFR

2012-10-01

... station may transmit with a transmitter power exceeding 1.5 kW PEP. (c) No station may transmit with a transmitter power output exceeding 200 W PEP: (1) On the 10.10-10.15 MHz segment; (2) On the 3.525-3.60 MHz, 7... Regions 1 or 3. (d) No station may transmit with a transmitter power exceeding 25 W PEP on the VHF 1.25 m...

High-power transmitter automation, part 2

NASA Technical Reports Server (NTRS)

Gregg, M. A.

1981-01-01

The current status of the transmitter automation development is reported. The work described is applicable to all transmitters in the Deep Space Network. New interface and software designs are described which improve reliability and reduce the time required for subsystem turn on and klystron saturation.

47 CFR 101.129 - Transmitter location.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Transmitter location. 101.129 Section 101.129 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.129 Transmitter location. (a) The applicant must determine, prior to...

47 CFR 101.807 - Transmitter power.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Transmitter power. 101.807 Section 101.807 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.807 Transmitter power. Stations in this service will...

47 CFR 101.807 - Transmitter power.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Transmitter power. 101.807 Section 101.807 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.807 Transmitter power. Stations in this service will...

47 CFR 101.807 - Transmitter power.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transmitter power. 101.807 Section 101.807 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.807 Transmitter power. Stations in this service will...

47 CFR 101.807 - Transmitter power.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Transmitter power. 101.807 Section 101.807 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.807 Transmitter power. Stations in this service will...

47 CFR 101.129 - Transmitter location.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Transmitter location. 101.129 Section 101.129 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.129 Transmitter location. (a) The applicant must determine, prior to...

47 CFR 101.807 - Transmitter power.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Transmitter power. 101.807 Section 101.807 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.807 Transmitter power. Stations in this service will...

International Intercomparison of Regular Transmittance Scales

NASA Astrophysics Data System (ADS)

Eckerle, K. L.; Sutter, E.; Freeman, G. H. C.; Andor, G.; Fillinger, L.

1990-01-01

An intercomparison of the regular spectral transmittance scales of NIST, Gaithersburg, MD (USA); PTB, Braunschweig (FRG); NPL, Teddington, Middlesex (UK); and OMH, Budapest (H) was accomplished using three sets of neutral glass filters with transmittances ranging from approximately 0.92 to 0.001. The difference between the results from the reference spectrophotometers of the laboratories was generally smaller than the total uncertainty of the interchange. The relative total uncertainty ranges from 0.05% to 0.75% for transmittances from 0.92 to 0.001. The sample-induced error was large - contributing 40% or more of the total except in a few cases.

NRL transmittance measurements at DIRT-III

NASA Astrophysics Data System (ADS)

Curcio, J. A.; Haught, K. M.; Woytko, M. A.; Gott, C.

1981-06-01

This is a final report on NRL experiments at the DIRT-III tests at Fort Polk, Louisiana in April - May 1980. Spectral transmission data at 3 wavelengths 0.55 microns, 1.06 microns and 10.4 microns is reported for 27 events in natural soil and various prepared soils. Spectral transmittance of smoke and dust clouds generated by explosive charges was found to be independent of wavelengths in about 50% of the events where useful data was obtained. When the charge was buried in wet natural soil transmittance at 10.4 microns was transmittance at 0.55 microns .

A Consistency Evaluation and Calibration Method for Piezoelectric Transmitters.

PubMed

Zhang, Kai; Tan, Baohai; Liu, Xianping

2017-04-28

Array transducer and transducer combination technologies are evolving rapidly. While adapting transmitter combination technologies, the parameter consistencies between each transmitter are extremely important because they can determine a combined effort directly. This study presents a consistency evaluation and calibration method for piezoelectric transmitters by using impedance analyzers. Firstly, electronic parameters of transmitters that can be measured by impedance analyzers are introduced. A variety of transmitter acoustic energies that are caused by these parameter differences are then analyzed and certified and, thereafter, transmitter consistency is evaluated. Lastly, based on the evaluations, consistency can be calibrated by changing the corresponding excitation voltage. Acoustic experiments show that this method accurately evaluates and calibrates transducer consistencies, and is easy to realize.

A Consistency Evaluation and Calibration Method for Piezoelectric Transmitters

PubMed Central

Zhang, Kai; Tan, Baohai; Liu, Xianping

2017-01-01

Array transducer and transducer combination technologies are evolving rapidly. While adapting transmitter combination technologies, the parameter consistencies between each transmitter are extremely important because they can determine a combined effort directly. This study presents a consistency evaluation and calibration method for piezoelectric transmitters by using impedance analyzers. Firstly, electronic parameters of transmitters that can be measured by impedance analyzers are introduced. A variety of transmitter acoustic energies that are caused by these parameter differences are then analyzed and certified and, thereafter, transmitter consistency is evaluated. Lastly, based on the evaluations, consistency can be calibrated by changing the corresponding excitation voltage. Acoustic experiments show that this method accurately evaluates and calibrates transducer consistencies, and is easy to realize. PMID:28452947

Low-cost CWDM transmitter package

NASA Astrophysics Data System (ADS)

Bhandarkar, Navin; Castillega, Jaime

2005-03-01

A low-cost coarse-wavelength-division multiplexer (CWDM) transmitter that combines four channels (wavelengths) in the infrared spectrum (~1310 nm) in a small form-factor un-cooled package is demonstrated. The package utilizes precision molded optics to multiplex beams from four grating-outcoupled surface-emitting (GSE) lasers into a single beam suitable for coupling into multimode fiber. This paper summarizes the optical and opto-mechanical design, fabrication and assembly of prototypes, and optical, thermal and electrical measurement results of the prototypes. This unique design enables multiplexing of wavelengths without the use of filters, waveguides, couplers and fiber splicing. Commercial fabrication and alignment technology is used to manufacture the package, resulting in a more robust, reliable and low-cost transmitter. The transmitter package is enabled by the unique characteristics of the long-wavelength GSE laser.

Digital coherent receiver based transmitter penalty characterization.

PubMed

Geisler, David J; Kaufmann, John E

2016-12-26

For optical communications links where receivers are signal-power-starved, such as through free-space, it is important to design transmitters and receivers that can operate as close as practically possible to theoretical limits. A total system penalty is typically assessed in terms of how far the end-to-end bit-error rate (BER) is from these limits. It is desirable, but usually difficult, to determine the division of this penalty between the transmitter and receiver. This paper describes a new rigorous and computationally based method that isolates which portion of the penalty can be assessed against the transmitter. There are two basic parts to this approach: (1) use of a coherent optical receiver to perform frequency down-conversion of a transmitter's optical signal waveform to the electrical domain, preserving both optical field amplitude and phase information, and (2): software-based analysis of the digitized electrical waveform. The result is a single numerical metric that quantifies how close a transmitter's signal waveform is to the ideal, based on its BER performance with a perfect software-defined matched-filter receiver demodulator. A detailed description of applying the proposed methodology to the waveform characterization of an optical burst-mode differential phase-shifted keying (DPSK) transmitter is experimentally demonstrated.

Distributed data transmitter

DOEpatents

Brown, Kenneth Dewayne [Grain Valley, MO; Dunson, David [Kansas City, MO

2006-08-08

A distributed data transmitter (DTXR) which is an adaptive data communication microwave transmitter having a distributable architecture of modular components, and which incorporates both digital and microwave technology to provide substantial improvements in physical and operational flexibility. The DTXR has application in, for example, remote data acquisition involving the transmission of telemetry data across a wireless link, wherein the DTXR is integrated into and utilizes available space within a system (e.g., a flight vehicle). In a preferred embodiment, the DTXR broadly comprises a plurality of input interfaces; a data modulator; a power amplifier; and a power converter, all of which are modularly separate and distinct so as to be substantially independently physically distributable and positionable throughout the system wherever sufficient space is available.

Distributed data transmitter

DOEpatents

Brown, Kenneth Dewayne [Grain Valley, MO; Dunson, David [Kansas City, MO

2008-06-03

A distributed data transmitter (DTXR) which is an adaptive data communication microwave transmitter having a distributable architecture of modular components, and which incorporates both digital and microwave technology to provide substantial improvements in physical and operational flexibility. The DTXR has application in, for example, remote data acquisition involving the transmission of telemetry data across a wireless link, wherein the DTXR is integrated into and utilizes available space within a system (e.g., a flight vehicle). In a preferred embodiment, the DTXR broadly comprises a plurality of input interfaces; a data modulator; a power amplifier; and a power converter, all of which are modularly separate and distinct so as to be substantially independently physically distributable and positionable throughout the system wherever sufficient space is available.

47 CFR 90.215 - Transmitter measurements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transmitter measurements. 90.215 Section 90.215... MOBILE RADIO SERVICES General Technical Standards § 90.215 Transmitter measurements. (a) The licensee of... current station authorization. On authorizations stating only the input power to the final radiofrequency...

47 CFR 22.657 - Transmitter locations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Transmitter locations. 22.657 Section 22.657... Paging and Radiotelephone Service 470-512 Mhz Trunked Mobile Operation § 22.657 Transmitter locations... public mobile operations on these channels will occur. The protected TV station locations specified in...

Determination and application of location and angular orientation of a pill transmitter within a body

NASA Technical Reports Server (NTRS)

Schipper, John F. (Inventor)

2009-01-01

A mobile pill transmitter system that moves through or adjacent to one or more organs in an animal's body and that provides signals from which the pill's present location and/or present angular orientation can be determined. The system also provides signals from which the present roll angle of the pill, about a selected axis, can be determined. When the location coordinates and the roll angle of the pill are within selected ranges, an aperture on the pill container releases a selected chemical into or onto the body. Optionally, the pill as it moves also provides a sequence of visually perceptible images; the times for image formation may correspond to times at which the pill transmitter system location or image satisfies one or at least four different criteria.

47 CFR 101.129 - Transmitter location.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transmitter location. 101.129 Section 101.129... SERVICES Technical Standards § 101.129 Transmitter location. (a) The applicant must determine, prior to... adequate to render the service proposed. In cases of questionable antenna locations, it is desirable to...

Linopirdine. A depolarization-activated releaser of transmitters for treatment of dementia.

PubMed

Tam, S W; Zaczek, R

1995-01-01

Linopirdine (DuP 996, AVIVA), currently in Phase III clinical trial for the treatment of Alzheimer's disease, is a representative of a class of novel molecules which enhances the stimulus-evoked but not basal release of several neurotransmitters including ACh, DA, 5-HT and Glu. Linopiridine has been shown to enhance ACh release in the hippocampus in vivo. In addition, linopiridine produces a number of effects including EEG patterns of enhanced vigilance, induction of c-fos expression in cerebral cortex, reduction of the increase of cerebral glucose utilization induced by hypoxia, and improved performance in animal models of learning and memory. The specific action of linopiridine on depolarized neurons but not on basal release suggests that compounds of this class will enhance normal brain activity and not lead to a non-specific activation. Furthermore, the effect of linopiridine on multiple neurotransmitter systems that are deficient in Alzheimer's disease suggests that this class of agents may be more efficacious in the treatment of dementia than therapies aimed at individual neurotransmitters systems.

47 CFR 73.759 - Auxiliary transmitters.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false Auxiliary transmitters. 73.759 Section 73.759... transmitter, necessitating discontinuance of its operation for a period not to exceed 5 days. (This includes... required for periods in excess of 5 days, request therefor shall be in accordance with § 73.3542 of this...

47 CFR 73.759 - Auxiliary transmitters.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Auxiliary transmitters. 73.759 Section 73.759... transmitter, necessitating discontinuance of its operation for a period not to exceed 5 days. (This includes... required for periods in excess of 5 days, request therefor shall be in accordance with § 73.3542 of this...

A radio transmitter attachment technique for soras

USGS Publications Warehouse

Haramis, G.M.; Kearns, G.D.

2000-01-01

We modified a figure-8 leg-loop harness designed for small passerines to attach successfully 1.8-g radio transmitters over the synsacrum of migrant Soras (Porzana carolina). Because of the short caudal region of Soras, addition of a waist loop was critical to securing the transmitter while leg loops were maintained to center the package. Thin gauge (0.6-mm diameter) elastic thread proved ideal for transmitter attachment and allowed for freedom of movement and girth expansion associated with fattening during a 6-10 week stopover. Of 110 Soras radio tagged during three field seasons, only a single mortality was observed and only a single bird lost its transmitter. Migration from the study area was confirmed for 76 (69%) and suspected for another 25 birds (total 92%).

Digital transmitter for data bus communications system

NASA Technical Reports Server (NTRS)

Proch, G. E. (Inventor)

1975-01-01

An improved digital transmitter for transmitting serial pulse code modulation (pcm) data at high bit rates over a transmission line is disclosed. When not transmitting, the transmitter features a high output impedance which prevents the transmitter from loading the transmission line. The pcm input is supplied to a logic control circuit which produces two discrete logic level signals which are supplied to an amplifier. The amplifier, which is transformer coupled to the output isolation circuitry, converts the discrete logic level signals to two high current level, ground isolated signals in the secondary windings of the coupling transformer. The latter signals are employed as inputs to the isolation circuitry which includes two series transistor pairs operating into a hybrid transformer functioning to isolate the transmitter circuitry from the transmission line.

Transmittance measurements at DIRT-II

NASA Astrophysics Data System (ADS)

Curcio, J. A.; Haught, K. M.; Woytko, M. A.

1980-07-01

This is a report on the NRL experiments at the DIRT-II tests sponsored by the Atmospheric Sciences Laboratory at the White Sands Missile Range in July 1970. The NRL experiment was designed to measure spectral transmittance through smoke and dust clouds generated by detonations of various explosive charges and also by impact of artillery rounds. Spectral transmission data as a function of time for 0.55 micrometers, 1.06 micrometers, and 10.37 micrometers were obtained for 63 events comprised of static detonations and artillery rounds. Transmission data for 1.06 micrometers, in most cases were similar and equal to 0.55 micrometers. In dry soil conditions the 10.37 micrometers channel showed higher transmittance values than the visible channel. There are indications that 10.37 micrometers transmittance in wet soil events is lower than visible presumably because of strong liquid water absorption at the IR wavelength.

Estimation of in-vivo neurotransmitter release by brain microdialysis: the issue of validity.

PubMed

Di Chiara, G.; Tanda, G.; Carboni, E.

1996-11-01

Although microdialysis is commonly understood as a method of sampling low molecular weight compounds in the extracellular compartment of tissues, this definition appears insufficient to specifically describe brain microdialysis of neurotransmitters. In fact, transmitter overflow from the brain into dialysates is critically dependent upon the composition of the perfusing Ringer. Therefore, the dialysing Ringer not only recovers the transmitter from the extracellular brain fluid but is a main determinant of its in-vivo release. Two types of brain microdialysis are distinguished: quantitative micro-dialysis and conventional microdialysis. Quantitative microdialysis provides an estimate of neurotransmitter concentrations in the extracellular fluid in contact with the probe. However, this information might poorly reflect the kinetics of neurotransmitter release in vivo. Conventional microdialysis involves perfusion at a constant rate with a transmitter-free Ringer, resulting in the formation of a steep neurotransmitter concentration gradient extending from the Ringer into the extracellular fluid. This artificial gradient might be critical for the ability of conventional microdialysis to detect and resolve phasic changes in neurotransmitter release taking place in the implanted area. On the basis of these characteristics, conventional microdialysis of neurotransmitters can be conceptualized as a model of the in-vivo release of neurotransmitters in the brain. As such, the criteria of face-validity, construct-validity and predictive-validity should be applied to select the most appropriate experimental conditions for estimating neurotransmitter release in specific brain areas in relation to behaviour.

Effects of radio transmitters on migrating wood thrushes

USGS Publications Warehouse

Powell, L.A.; Krementz, D.G.; Lang, J.D.; Conroy, M.J.

1998-01-01

We quantified the effects of radio transmitters on Wood Thrushes (Hylocichla mustelina) using 4 yr of banding and telemetry data from Piedmont National Wildlife Refuge, Georgia. Flight performance models suggest that the 1.6-g transmitter shortens the migratory range of Wood Thrushes by only 60 km, and the estimated migratory range is adequate to accomplish migration even with limited fat stores. We used two strengths of line, 5- and 9-kg test-strength braided Dacron, to attach the transmitters using the thigh-harness method. We recaptured 13 returning radio-marked Wood Thrushes, seven of which were still marked. Six of the seven birds marked with the 5-kg test harnesses lost their transmitters within 1 yr while all six of the 9-kg test harnesses were still attached up to 21 mo later. Radio-marking did not reduce the return rates of adults and immatures, and the transmitters did not cause radio-marked birds to lose more mass than banded-only birds. Wood Thrushes can successfully carry a transmitter during migration with no detectable negative effects. We recommend continued use of the thigh-harness method, but we encourage the use of 5-kg cotton line.

47 CFR 22.573 - Use of base transmitters as repeaters.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 2 2013-10-01 2013-10-01 false Use of base transmitters as repeaters. 22.573... of base transmitters as repeaters. As an additional function, base transmitters may be used as repeaters. Licensees must be able to turn the base transmitter on or off from the control point regardless...

47 CFR 22.573 - Use of base transmitters as repeaters.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 2 2011-10-01 2011-10-01 false Use of base transmitters as repeaters. 22.573... of base transmitters as repeaters. As an additional function, base transmitters may be used as repeaters. Licensees must be able to turn the base transmitter on or off from the control point regardless...

47 CFR 22.573 - Use of base transmitters as repeaters.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 2 2012-10-01 2012-10-01 false Use of base transmitters as repeaters. 22.573... of base transmitters as repeaters. As an additional function, base transmitters may be used as repeaters. Licensees must be able to turn the base transmitter on or off from the control point regardless...

47 CFR 22.573 - Use of base transmitters as repeaters.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Use of base transmitters as repeaters. 22.573... of base transmitters as repeaters. As an additional function, base transmitters may be used as repeaters. Licensees must be able to turn the base transmitter on or off from the control point regardless...

TWT transmitter fault prediction based on ANFIS

NASA Astrophysics Data System (ADS)

Li, Mengyan; Li, Junshan; Li, Shuangshuang; Wang, Wenqing; Li, Fen

2017-11-01

Fault prediction is an important component of health management, and plays an important role in the reliability guarantee of complex electronic equipments. Transmitter is a unit with high failure rate. The cathode performance of TWT is a common fault of transmitter. In this dissertation, a model based on a set of key parameters of TWT is proposed. By choosing proper parameters and applying adaptive neural network training model, this method, combined with analytic hierarchy process (AHP), has a certain reference value for the overall health judgment of TWT transmitters.

Capsaicin modulates acetylcholine release at the myoneural junction.

PubMed

Thyagarajan, Baskaran; Potian, Joseph G; Baskaran, Padmamalini; McArdle, Joseph J

2014-12-05

Transient receptor potential (TRP) proteins are non-selective cation channel proteins that are expressed throughout the body. Previous studies demonstrated the expression of TRP Vanilloid 1 (TRPV1), capsaicin (CAP) receptor, in sensory neurons. Recently, we reported TRPV1 expression in mouse motor nerve terminals [MNTs; (Thyagarajan et al., 2009)], where we observed that CAP protected MNTs from botulinum neurotoxin A (BoNT/A). Phrenic nerve diaphragm nerve muscle preparations (NMP) isolated from isoflurane anesthetized adult mice were analyzed for twitch tension, spontaneous (mEPCs) and nerve stimulus evoked (EPCs) acetylcholine release. When acutely applied to isolated NMP, CAP produced a concentration-dependent decline of twitch tension and produced a significant decline in the amplitude of EPCs and quantal content without any effect on the mEPCs. The suppression of nerve stimulus evoked acetylcholine release by CAP was antagonized by capsazepine (CPZ), a TRPV1 antagonist. CAP did not suppress phrenic nerve stimulus evoked acetylcholine release in TRPV1 knockout mice. Also, CAP treatment, in vitro, interfered with the localization of adapter protein 2 in cholinergic Neuro 2a cells. Wortmannin, (WMN; non-selective phosphoinositol kinase inhibitor), mimicked the effects of CAP by inhibiting the acetylcholine exocytosis. Our data suggest that TRPV1 proteins expressed at the MNT are coupled to the exo-endocytic mechanisms to regulate neuromuscular functions. Copyright © 2014 Elsevier B.V. All rights reserved.

Behavior of sandhill cranes harnessed with different satellite transmitters

USGS Publications Warehouse

Olsen, Glenn H.; Ellis, D.H.; Landfried, S.E.; Miller, L.H.; Klugman, S.S.; Fuller, M.R.; Vermillion, C.H.

1992-01-01

The effectiveness of various attachment methods and designs of platform transmitting terminals (PTT's) was tested on captive sandhill cranes (Grus canadensis) at the Patuxent Wildlife Research Center, Laurel, Maryland, during 1989-91. Combinations of attachment and transmitter designs included neoprene cord harness with batteries separate from the transmitter (2 harness designs), Teflon ribbon harness with batteries incorporated into the transmitter package (4 transmitter models), and a package attached directly to the bird with epoxy glue only. Physical effects seen on cranes wearing PTT's ranged from skin lacerations (caused by rubbing of harness material) to no observed effects (other than feather wear). The most successful harness material and design utilized a Teflon ribbon harness with the 4 ribbon ends from the transmitter forming a neck loop and a body loop joined at the sternum. Time spent by sandhill cranes performing most activities did not change after transmitter attachment using this harness method.

47 CFR 87.143 - Transmitter control requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Section 87.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO..., the control point for an automatically controlled enroute station is the computer facility which controls the transmitter. Any computer controlled transmitter must be equipped to automatically shut down...

47 CFR 87.143 - Transmitter control requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Section 87.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO..., the control point for an automatically controlled enroute station is the computer facility which controls the transmitter. Any computer controlled transmitter must be equipped to automatically shut down...

47 CFR 87.143 - Transmitter control requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Section 87.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO..., the control point for an automatically controlled enroute station is the computer facility which controls the transmitter. Any computer controlled transmitter must be equipped to automatically shut down...

47 CFR 87.143 - Transmitter control requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Section 87.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO..., the control point for an automatically controlled enroute station is the computer facility which controls the transmitter. Any computer controlled transmitter must be equipped to automatically shut down...

47 CFR 87.143 - Transmitter control requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Section 87.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO..., the control point for an automatically controlled enroute station is the computer facility which controls the transmitter. Any computer controlled transmitter must be equipped to automatically shut down...

Optical Communications Transmitter

NASA Image and Video Library

1965-11-10

S65-42598 (10 Nov. 1965) --- Douglas S. Idlly, Electromagnetic Systems Branch, Instrumentation and Electronic Systems Division, illustrates an Optical Communications Transmitter (LASER) during a briefing at the news center of the Manned Spacecraft Center in Houston, Texas. Photo credit: NASA

Efficacy of using radio transmitters to monitor least tern chicks

USGS Publications Warehouse

Whittier, Joanna B.; Leslie, David M.

2005-01-01

Little is known about Least Tern (Sterna antillarum) chicks from the time they leave the nest until fledging because they are highly mobile and cryptically colored. We evaluated the efficacy of using radiotelemetry to monitor Interior Least Tern (S. a. athalassos) chicks at Salt Plains National Wildlife Refuge, Oklahoma. In 1999, we attached radio transmitters to 26 Least Tern chicks and tracked them for 2-17 days. No adults abandoned their chicks after transmitters were attached. Transmitters did not appear to alter growth rates of transmittered chicks (P = 0.36) or prevent feather growth, although dermal irritation was observed on one chick. However, without frequent reattachment, transmitters generally did not remain on chicks <1 week old for more than 2 days because of feather growth and transmitter removal, presumably by adult terns. Although the presence of transmitters did not adversely affect Least Tern chicks, future assessments should investigate nonintrusive methods to improve retention of transmitters on young chicks and reduce the number of times that chicks need to be handled.

47 CFR 22.507 - Number of transmitters per station.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 2 2012-10-01 2012-10-01 false Number of transmitters per station. 22.507... PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.507 Number of transmitters per station. This section concerns the number of transmitters licensed under each station authorization in the...

47 CFR 22.377 - Certification of transmitters.

Code of Federal Regulations, 2011 CFR

2011-10-01

... MOBILE SERVICES Operational and Technical Requirements Technical Requirements § 22.377 Certification of transmitters. Except as provided in paragraph (b) of this section, transmitters used in the Public Mobile Services, including those used with signal boosters, in-building radiation systems and cellular repeaters...

Transmitter switch for high-power microwave output

NASA Technical Reports Server (NTRS)

Wiggins, C. P.; Leu, R. K.

1975-01-01

Combiner system can be used for combining output powers of two transmitters or for switching from one to the other. This can be done when pair of transmitters operate on same frequency and carriers are phase coherent as by excitation from single exciter.

High-power transmitter automation. [deep space network

NASA Technical Reports Server (NTRS)

Gosline, R.

1980-01-01

The current status of the transmitter automation development applicable to all transmitters in the deep space network is described. Interface and software designs are described that improve reliability and reduce the time required for subsystem turn-on and klystron saturation to less than 10 minutes.

Role of voltage-sensitive receptors in nicotinic transmission.

PubMed Central

Lester, H A; Koblin, D D; Sheridan, R E

1978-01-01

This paper compares the conductance induced by bath-applied acetyl-choline (ACh) and by the same transmitter released from nerve terminals at Electrophorus electroplaques. For the former case, dose-response relations are characterized by the maximal agonist-induced conductance, rgamma (130 mmho/cm2), and by the concentration which induces half this conductance; this concentration is termed Kapp and equals 50 micron at -85 mV. For the latter case, neurally evoked postsynaptic currents (PSCs) are characterized by the peak conductance during strongly facilitated release, gPSC, and by the rate constant for decay, alpha. Since gPSC roughly equals rgamma, it is concluded that the PSC activates nearly all available receptor channels. These and other data agree with recent estimates that during the growth phase of the quantal response, (a) the ACh concentration is at least several hundred micromolar; and (b) most nearby channels are activated. However both alpha and Kapp increase during depolarization, at a rate of about e-fold per 86 mV. These observations on voltage sensitivity suggest that a suprathreshold synaptic event is rapidly terminated because the action potential abruptly releases ACh molecules from receptors. PMID:630039

29 CFR 1921.15 - Transmittal of record.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Transmittal of record. 1921.15 Section 1921.15 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... WORKERS' COMPENSATION ACT Decision and Order § 1921.15 Transmittal of record. Immediately following the...

47 CFR 22.377 - Certification of transmitters.

Code of Federal Regulations, 2010 CFR

2010-10-01

... MOBILE SERVICES Operational and Technical Requirements Technical Requirements § 22.377 Certification of transmitters. Except as provided in paragraph (b) of this section, transmitters used in the Public Mobile... certificated when the station is ready for service, not necessarily at the time of filing an application. (a...

Topology-dependent rationality and quantal response equilibria in structured populations

NASA Astrophysics Data System (ADS)

Roman, Sabin; Brede, Markus

2017-05-01

Given that the assumption of perfect rationality is rarely met in the real world, we explore a graded notion of rationality in socioecological systems of networked actors. We parametrize an actors' rationality via their place in a social network and quantify system rationality via the average Jensen-Shannon divergence between the games Nash and logit quantal response equilibria. Previous work has argued that scale-free topologies maximize a system's overall rationality in this setup. Here we show that while, for certain games, it is true that increasing degree heterogeneity of complex networks enhances rationality, rationality-optimal configurations are not scale-free. For the Prisoner's Dilemma and Stag Hunt games, we provide analytic arguments complemented by numerical optimization experiments to demonstrate that core-periphery networks composed of a few dominant hub nodes surrounded by a periphery of very low degree nodes give strikingly smaller overall deviations from rationality than scale-free networks. Similarly, for the Battle of the Sexes and the Matching Pennies games, we find that the optimal network structure is also a core-periphery graph but with a smaller difference in the average degrees of the core and the periphery. These results provide insight on the interplay between the topological structure of socioecological systems and their collective cognitive behavior, with potential applications to understanding wealth inequality and the structural features of the network of global corporate control.

Topology-dependent rationality and quantal response equilibria in structured populations.

PubMed

Roman, Sabin; Brede, Markus

2017-05-01

Given that the assumption of perfect rationality is rarely met in the real world, we explore a graded notion of rationality in socioecological systems of networked actors. We parametrize an actors' rationality via their place in a social network and quantify system rationality via the average Jensen-Shannon divergence between the games Nash and logit quantal response equilibria. Previous work has argued that scale-free topologies maximize a system's overall rationality in this setup. Here we show that while, for certain games, it is true that increasing degree heterogeneity of complex networks enhances rationality, rationality-optimal configurations are not scale-free. For the Prisoner's Dilemma and Stag Hunt games, we provide analytic arguments complemented by numerical optimization experiments to demonstrate that core-periphery networks composed of a few dominant hub nodes surrounded by a periphery of very low degree nodes give strikingly smaller overall deviations from rationality than scale-free networks. Similarly, for the Battle of the Sexes and the Matching Pennies games, we find that the optimal network structure is also a core-periphery graph but with a smaller difference in the average degrees of the core and the periphery. These results provide insight on the interplay between the topological structure of socioecological systems and their collective cognitive behavior, with potential applications to understanding wealth inequality and the structural features of the network of global corporate control.

31 CFR 538.319 - U.S. registered money transmitter.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false U.S. registered money transmitter. 538.319 Section 538.319 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 538.319 U.S. registered money transmitter. The term U.S. registered money transmitter means any...

31 CFR 538.319 - U.S. registered money transmitter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false U.S. registered money transmitter. 538.319 Section 538.319 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 538.319 U.S. registered money transmitter. The term U.S. registered money transmitter means any...

31 CFR 538.319 - U.S. registered money transmitter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false U.S. registered money transmitter. 538.319 Section 538.319 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 538.319 U.S. registered money transmitter. The term U.S. registered money transmitter means any...

31 CFR 538.319 - U.S. registered money transmitter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false U.S. registered money transmitter. 538.319 Section 538.319 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 538.319 U.S. registered money transmitter. The term U.S. registered money transmitter means any...

31 CFR 542.323 - U.S. registered money transmitter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false U.S. registered money transmitter. 542.323 Section 542.323 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 542.323 U.S. registered money transmitter. The term U.S. registered money transmitter means any...

31 CFR 537.323 - U.S. registered money transmitter.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false U.S. registered money transmitter. 537.323 Section 537.323 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 537.323 U.S. registered money transmitter. The term U.S. registered money transmitter means any...

31 CFR 537.323 - U.S. registered money transmitter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false U.S. registered money transmitter. 537.323 Section 537.323 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 537.323 U.S. registered money transmitter. The term U.S. registered money transmitter means any...

31 CFR 537.323 - U.S. registered money transmitter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false U.S. registered money transmitter. 537.323 Section 537.323 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 537.323 U.S. registered money transmitter. The term U.S. registered money transmitter means any...

31 CFR 537.323 - U.S. registered money transmitter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false U.S. registered money transmitter. 537.323 Section 537.323 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Definitions § 537.323 U.S. registered money transmitter. The term U.S. registered money transmitter means any...

An injectable acoustic transmitter for juvenile salmon

DOE PAGES

Deng, Zhiqun; Carlson, Thomas J.; Li, Huidong; ...

2015-01-29

Salmon recovery, and the potential detrimental effects of dams on fish, has been attracting national attention in due to great environmental and economic implications. Acoustic Telemetry has been the primary method for studying salmon passage. However, the size of the existing transmitters limits the minimum size of fish that can be studied, introducing bias to the study results. We developed the first acoustic fish transmitter that can be implanted by injection instead of surgery. The new injectable transmitter offers improved performance and 30% weight reduction. Because the new transmitter costs significantly less to use, substantially reduces adverse effects of implantation,more » and provides additional biological benefits for tagged fish, it will become the enabling technology for studying migration behavior and survival of species and sizes of fish that have never been studied before. This will lead to critical information for salmon recovery and the development of fish-friendly hydroelectric systems.« less

An injectable acoustic transmitter for juvenile salmon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Zhiqun; Carlson, Thomas J.; Li, Huidong

Salmon recovery, and the potential detrimental effects of dams on fish, has been attracting national attention in due to great environmental and economic implications. Acoustic Telemetry has been the primary method for studying salmon passage. However, the size of the existing transmitters limits the minimum size of fish that can be studied, introducing bias to the study results. We developed the first acoustic fish transmitter that can be implanted by injection instead of surgery. The new injectable transmitter offers improved performance and 30% weight reduction. Because the new transmitter costs significantly less to use, substantially reduces adverse effects of implantation,more » and provides additional biological benefits for tagged fish, it will become the enabling technology for studying migration behavior and survival of species and sizes of fish that have never been studied before. This will lead to critical information for salmon recovery and the development of fish-friendly hydroelectric systems.« less

Effect of surfactant chain length on drug release kinetics from microemulsion-laden contact lenses.

PubMed

Maulvi, Furqan A; Desai, Ankita R; Choksi, Harsh H; Patil, Rahul J; Ranch, Ketan M; Vyas, Bhavin A; Shah, Dinesh O

2017-05-30

The effect of surfactant chain lengths [sodium caprylate (C 8 ), Tween 20 (C 12 ), Tween 80 (C 18 )] and the molecular weight of block copolymers [Pluronic F68 and Pluronic F 127] were studied to determine the stability of the microemulsion and its effect on release kinetics from cyclosporine-loaded microemulsion-laden hydrogel contact lenses in this work. Globule size and dilution tests (transmittance) suggested that the stability of the microemulsion increases with increase in the carbon chain lengths of surfactants and the molecular weight of pluronics. The optical transmittance of direct drug-laden contact lenses [DL-100] was low due to the precipitation of hydrophobic drugs in the lenses, while in microemulsion-laden lenses, the transmittance was improved when stability of the microemulsion was achieved. The results of in vitro release kinetics revealed that drug release was sustained to a greater extent as the stability of microemulsion was improved as well. This was evident in batch PF127-T80, which showed sustained release for 15days in comparison to batch DL-100, which showed release up to 7days. An in vivo drug release study in rabbit tear fluid showed significant increase in mean residence time (MRT) and area under curve (AUC) with PF-127-T80 lenses (stable microemulsion) in comparison to PF-68-SC lenses (unstable microemulsion) and DL-100 lenses. This study revealed the correlation between the stability of microemulsion and the release kinetics of drugs from contact lenses. Thus, it was inferred that the stable microemulsion batches sustained the release of hydrophobic drugs, such as cyclosporine from contact lenses for an extended period of time without altering critical lens properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Interaction of aberrations, diffraction, and quantal fluctuations determine the impact of pupil size on visual quality.

PubMed

Xu, Renfeng; Wang, Huachun; Thibos, Larry N; Bradley, Arthur

2017-04-01

Our purpose is to develop a computational approach that jointly assesses the impact of stimulus luminance and pupil size on visual quality. We compared traditional optical measures of image quality and those that incorporate the impact of retinal illuminance dependent neural contrast sensitivity. Visually weighted image quality was calculated for a presbyopic model eye with representative levels of chromatic and monochromatic aberrations as pupil diameter was varied from 7 to 1 mm, stimulus luminance varied from 2000 to 0.1  cd/m², and defocus varied from 0 to -2 diopters. The model included the effects of quantal fluctuations on neural contrast sensitivity. We tested the model's predictions for five cycles per degree gratings by measuring contrast sensitivity at 5  cyc/deg. Unlike the traditional Strehl ratio and the visually weighted area under the modulation transfer function, the visual Strehl ratio derived from the optical transfer function was able to capture the combined impact of optics and quantal noise on visual quality. In a well-focused eye, provided retinal illuminance is held constant as pupil size varies, visual image quality scales approximately as the square root of illuminance because of quantum fluctuations, but optimum pupil size is essentially independent of retinal illuminance and quantum fluctuations. Conversely, when stimulus luminance is held constant (and therefore illuminance varies with pupil size), optimum pupil size increases as luminance decreases, thereby compensating partially for increased quantum fluctuations. However, in the presence of -1 and -2 diopters of defocus and at high photopic levels where Weber's law operates, optical aberrations and diffraction dominate image quality and pupil optimization. Similar behavior was observed in human observers viewing sinusoidal gratings. Optimum pupil size increases as stimulus luminance drops for the well-focused eye, and the benefits of small pupils for improving

Thermoregulatory effects of radiotelemetry transmitters on mallard ducklings

USGS Publications Warehouse

Bakken, G.S.; Reynolds, P.S.; Kenow, K.P.; Korschgen, C.E.; Boysen, A.F.

1996-01-01

Many telemetry transmitter attachments disrupt downy insulation, and may bias survival studies during cold weather by making ducklings more susceptible to chilling. We compared thermal responses of untreated 1-day-old mallards (Anas platyrhynchos) to ducklings carrying external sutured backpack or subcutaneously implanted transmitters. Ducklings carrying external transmitters showed areas of increased surface temperature in thermographic images. However, open-circuit respirometry studies at 5, 10, 15, 20, and 25 C and wind speeds of 0.1, 0.2, 0.5, and 1 m/s indicated no biologically significant differences in total heat production, net heat production, or short-term body mass loss. These results do not exclude the possibility of other negative effects of transmitters on duckling behavior and survival.

An ingestible temperature-transmitter

NASA Technical Reports Server (NTRS)

Pope, J. M.; Fryer, T. B.; Sandler, H.

1972-01-01

Pill-sized transmitter measures deep body temperature in studies of circadian rhythm and indicates general health. Ingestible device is a compromise between accuracy, circuit complexity, size and transmission range.

47 CFR 80.209 - Transmitter frequency tolerances.

Code of Federal Regulations, 2010 CFR

2010-10-01

... output power of 25 watts or less the frequency tolerance is 10 parts in 10 6. (b) When pulse modulation... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transmitter frequency tolerances. 80.209... SERVICES STATIONS IN THE MARITIME SERVICES General Technical Standards § 80.209 Transmitter frequency...

The effect of imiquimod on taste bud calcium transients and transmitter secretion.

PubMed

Huang, Anthony Y; Wu, Sandy Y

2016-11-01

Imiquimod is an immunomodulator approved for the treatment of basal cell carcinoma and has adverse side effects, including taste disturbances. Paracrine transmission, representing cell-cell communication within taste buds, has the potential to shape the final signals that taste buds transmit to the brain. Here, we tested the underlying assumption that imiquimod modifies taste transmitter secretion in taste buds of mice. Taste buds were isolated from C57BL/6J mice. The effects of imiquimod on transmitter release in taste buds were measured using calcium imaging with cellular biosensors, and examining the net effect of imiquimod on taste-evoked ATP secretion from mouse taste buds. Up to 72% of presynaptic (Type III) taste cells responded to 100 μM imiquimod with an increase in intracellular Ca 2+ concentrations. These Ca 2 + responses were inhibited by thapsigargin, an inhibitor of the sarco/endoplasmic reticulum Ca 2 + -ATPase, and by U73122, a PLC inhibitor, suggesting that the Ca 2 + mobilization elicited by imiquimod was dependent on release from internal Ca 2 + stores. Moreover, combining studies of Ca 2 + imaging with cellular biosensors showed that imiquimod evoked secretion of 5-HT, which then provided negative feedback onto receptor (Type II) cells to reduce taste-evoked ATP secretion. Our results provide evidence that there is a subset of taste cells equipped with a range of intracellular mechanisms that respond to imiquimod. The findings are also consistent with a role of imiquimod as an immune response modifier, which shapes peripheral taste responses via 5-HT signalling. © 2016 The British Pharmacological Society.

Effects of radio transmitters on nesting captive mallards

USGS Publications Warehouse

Houston, Robert A.; Greenwood, Raymond J.

1993-01-01

Radio packages may subtly affect bird behavior and condition, and thus could bias results from studies using this technique. To assess effects on reproduction of mallards (Anas platyrhynchos), we tested 3 types of back-mounted radio packages on captive females. Eight paired females were randomly assigned to each of 4 treatments: 4-g transmitter attached with sutures and glue, 10-g or 18-g transmitter attached with a harness, and no transmitter (control). All mallards were fed ad libitum. No differences were detected among treatments in number of clutches, clutch size, nesting interval, egg mass, or body mass; powers (range = 0.15-0.48) of tests were low. Feather wear and skin irritation around radio packages were minimal. Birds retained sutured transmitters for an average of 43.5 days (range = 3-106 days) and harness transmitters for the duration of the study (106 days). Sutures were not reliable and presently are not recommended as an attachment method. Caution is advised in applying these results to radio-equipped mallards in the wild.

Non-Neuronal Release of Gamma-Aminobutyric Acid by Embryonic Pluripotent Stem Cells

PubMed Central

Teng, Lin; Tang, Ya-Bin; Sun, Fan; An, Shi-Min; Zhang, Chun; Yang, Xin-Jie; Lv, Hao-Yu; Lu, Qin; Cui, Yong-Yao; Hu, Jin-Jia

2013-01-01

γ-Aminobutyric acid (GABA), the principle inhibitory transmitter in the mature central nervous system, is also involved in activities outside the nervous system. Recent studies have shown that functional GABA receptors are expressed in embryonic stem (ES) cells and these receptors control ES cell proliferation. However, it is not clear whether ES cells have their own GABAergic transmission output machinery that can fulfill GABA release or whether the cells merely process the GABA receptors by receiving and responding to the diffused GABA released elsewhere. To get further insight into this unresolved problem, we detected the repertoire of components for GABA synthesis, storage, reaction, and termination in ES and embryonal carcinoma stem cells by biological assays, and then directly quantified released GABA in the intercellular milieu from these pluripotent stem (PS) cells by an analytical chemical assay based on high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). We found that embryonic PS cells processed a GABAergic circuit machinery and spontaneously released GABA, which suggests the potential that embryonic PS cells could autonomously establish a GABA niche via release of the transmitter. PMID:23799822

Suomi NPP VIIRS solar diffuser screen transmittance model and its applications.

PubMed

Lei, Ning; Xiong, Xiaoxiong; Mcintire, Jeff

2017-11-01

The visible infrared imaging radiometer suite on the Suomi National Polar-orbiting Partnership satellite calibrates its reflective solar bands through observations of a sunlit solar diffuser (SD) panel. Sunlight passes through a perforated plate, referred to as the SD screen, before reaching the SD. It is critical to know whether the SD screen transmittance measured prelaunch is accurate. Several factors such as misalignments of the SD panel and the measurement apparatus could lead to errors in the measured transmittance and thus adversely impact on-orbit calibration quality through the SD. We develop a mathematical model to describe the transmittance as a function of the angles that incident light makes with the SD screen, and apply the model to fit the prelaunch measured transmittance. The results reveal that the model does not reproduce the measured transmittance unless the size of the apertures in the SD screen is quite different from the design value. We attribute the difference to the orientation alignment errors for the SD panel and the measurement apparatus. We model the alignment errors and apply our transmittance model to fit the prelaunch transmittance to retrieve the "true" transmittance. To use this model correctly, we also examine the finite source size effect on the transmittance. Furthermore, we compare the product of the retrieved "true" transmittance and the prelaunch SD bidirectional reflectance distribution function (BRDF) value to the value derived from on-orbit data to determine whether the prelaunch SD BRDF value is relatively accurate. The model is significant in that it can evaluate whether the SD screen transmittance measured prelaunch is accurate and help retrieve the true transmittance from the transmittance with measurement errors, consequently resulting in a more accurate sensor data product by the same amount.

Temperature responsive transmitter

NASA Technical Reports Server (NTRS)

Kleinberg, Leonard L. (Inventor)

1987-01-01

A temperature responsive transmitter is provided in which frequency varies linearly with temperature. The transmitter includes two identically biased transistors connected in parallel. A capacitor, which reflects into the common bases to generate negative resistance effectively in parallel with the capacitor, is connected to the common emitters. A crystal is effectively in parallel with the capacitor and the negative resistance. Oscillations occur if the magnitude of the absolute value of the negative resistance is less than the positive resistive impedance of the capacitor and the inductance of the crystal. The crystal has a large linear temperature coefficient and a resonant frequency which is substantially less than the gain-bandwidth product of the transistors to ensure that the crystal primarily determines the frequency of oscillation. A high-Q tank circuit having an inductor and a capacitor is connected to the common collectors to increase the collector current flow which in turn enhances the radiation of the oscillator frequency by the inductor.

Protons act as a transmitter for muscle contraction in C. elegans.

PubMed

Beg, Asim A; Ernstrom, Glen G; Nix, Paola; Davis, M Wayne; Jorgensen, Erik M

2008-01-11

Muscle contraction is normally mediated by the release of neurotransmitters from motor neurons. Here we demonstrate that protons can act as a direct transmitter from intestinal cells to stimulate muscle contraction. During the C. elegans defecation motor program the posterior body muscles contract even in the absence of neuronal inputs or vesicular neurotransmission. In this study, we demonstrate that the space between the intestine and the muscle is acidified just prior to muscle contraction and that the release of caged protons is sufficient to induce muscle contraction. PBO-4 is a putative Na+/H+ ion exchanger expressed on the basolateral membrane of the intestine, juxtaposed to the posterior body muscles. In pbo-4 mutants the extracellular space is not acidified and the muscles fail to contract. The pbo-5 and pbo-6 genes encode subunits of a "cys-loop" proton-gated cation channel required for muscles to respond to acidification. In heterologous expression assays the PBO receptor is half-maximally activated at a pH of 6.8. The identification of the mechanisms for release and reception of proton signals establishes a highly unusual mechanism for intercellular communication.

Protons act as a transmitter for muscle contraction in C. elegans

PubMed Central

Beg, Asim A.; Ernstrom, Glen G.; Nix, Paola; Davis, M. Wayne; Jorgensen, Erik M.

2008-01-01

Muscle contraction is normally mediated by the release of neurotransmitters from motor neurons. Here we demonstrate that protons can act as a direct transmitter from intestinal cells to stimulate muscle contraction. During the C. elegans defecation motor program the posterior body muscles contract even in the absence of neuronal inputs or vesicular neurotransmission. In this study, we demonstrate that the space between the intestine and the muscle is acidified just prior to muscle contraction and that the release of caged protons is sufficient to induce muscle contraction. PBO-4 is a putative Na+/H+ ion exchanger expressed on the basolateral membrane of the intestine, juxtaposed to the posterior body muscles. In pbo-4 mutants the extracellular space is not acidified and the muscles fail to contract. The pbo-5 and pbo-6 genes encode subunits of a ‘cys-loop’ proton-gated cation channel required for muscles to respond to acidification. In heterologous expression assays the PBO receptor is half-maximally activated at a pH of 6.8. The identification of the mechanisms for release and reception of proton signals establishes a highly unusual mechanism for intercellular communication. PMID:18191228

Evaluation of 3 radio transmitters and collar designs for Amazona

USGS Publications Warehouse

Meyers, J.M.

1996-01-01

I evaluated 3 radio transmitter attachments and designs for adult parrots. Two of the transmitters and attachments were similar to those used previously in the study on fledgling and adult parrots. I designed, in collaboration with the manufacturer, a third transmitter and attachment that provided protection of key areas from chewing and eventual destruction of the attachment or transmitter. This design was used successfully to radio-track parrots an average of 43.4 weeks (range = 35.9-51.6 weeks). It was the only transmitter of the 3 tested to operate without failure (>36 weeks) caused by chewing damage to the transmitter, antenna, collar, or attachment mechanism (Fisher's exact test, 3 df, P = 0.0003). Its adjustable collar, made from 59 kg-test stainless steel wire covered with plastic heat-shrink tubing, was sturdy and easy to apply. Transmitters for parrots should be enclosed in a protective metal case (brass) and have metal crimped tubes (brass or copper) protecting key areas, such as the base of the antenna and mechanism for attachment of the collar.

Effects of harness-attached transmitters on premigration and reproduction of Brant

USGS Publications Warehouse

Ward, David H.; Flint, Paul L.

1995-01-01

Radio transmitters are an important tool in waterfowl ecology studies, but little is known about their effects on free-ranging geese. We attached transmitters to female brant (Branta bernicla nigricans) to investigate migration schedules at a fall staging area, return rates to nesting grounds, and nesting rates of returning females in subsequent breeding seasons. Radio-tagged females (n = 62) carried either 35-g back-mounted transmitters attached with ribbon harnesses, or 26- or 32-g back-mounted transmitters affixed with plastic-coated wire harnesses (Dwyer 1972). Arrival and departure schedules at Izembek Lagoon, Alaska, did not differ (P > 0.05) between radio-tagged females and the entire population in 1987-89. Color-banded females with transmitters returned to the breeding colony in subsequent nesting seasons (1988-92) at a lower (P ≤ 0.003) rate (≤4%) than color-banded females without transmitters (57-83%). The 1 returning color-banded female with a transmitter did not breed, while an average 90% of the returning color-banded females without transmitters nested in subsequent breeding seasons (P = 0.005). Back-mounted, harness-attached transmitters may bias data in studies of waterfowl behavior, productivity, and survival.

47 CFR 95.667 - CB transmitter power.

Code of Federal Regulations, 2010 CFR

2010-10-01

... transmitter power. The dissipation rating of all the semiconductors or electron tubes which supply RF power to the antenna terminals of each CB transmitter must not exceed 10 W. For semiconductors, the dissipation... semiconductor. These values may be temperature de-rated by no more than 50 °C. For an electron tube, the...

47 CFR 95.667 - CB transmitter power.

Code of Federal Regulations, 2011 CFR

2011-10-01

... transmitter power. The dissipation rating of all the semiconductors or electron tubes which supply RF power to the antenna terminals of each CB transmitter must not exceed 10 W. For semiconductors, the dissipation... semiconductor. These values may be temperature de-rated by no more than 50 °C. For an electron tube, the...

A comparison of forest canopy transmittance estimators

Treesearch

E.R. Smith; Kurt H. Riitters

1994-01-01

Multiple sensors, and alternate statistical estimators, were tested for measuring canopy transmittance in four stands under a variety of sky conditions. On a given day, stand average transmittance estimates were insensitive to degree of synchronization of the sensors used to measure under-canopy and incoming radiation. In comparisons to periodic measurement of incoming...

Digital transmitter for data bus communications system

NASA Technical Reports Server (NTRS)

Proch, G. E.

1974-01-01

Digital transmitter designed for Manchester coded signals (and all signals with ac waveforms) generated at a rate of one megabit per second includes efficient output isolation circuit. Transmitter consists of logic control section, amplifier, and output isolation section. Output isolation circuit provides dynamic impedance at terminals as function of amplifier output level.

A standard operating procedure for the surgical implantation of transmitters in juvenile salmonids

USGS Publications Warehouse

Liedtke, T.L.; Beeman, J.W.; Gee, L.P.

2012-01-01

require large numbers of tagged fish. For example, a study conducted at the dams on the Columbia River and funded by the U.S. Army Corps of Engineers required tagging and monitoring of 40,000 juvenile salmon during a 3-month migration period (Counihan and others, 2006a, 2006b; Perry and others, 2006). To meet the demands of such a large study, the authors and CRRL staff refined the SOP to increase efficiency in the tagging process while maintaining high standards of fish care. The SOP has been used in laboratory and field settings for more than 15 years, and consistently has produced low mortality rates (<1 percent) and transmitter loss rates (<0.01 percent) in the 24-36 hours after tagging. In addition to describing the detailed surgical procedures required for transmitter implantation, this document provides guidance on fish collection, handling and holding, and the release of tagged fish. Although often overlooked, or at least underemphasized, these processes can have a large impact on the outcome of the tagging procedure. Stress associated with the individual steps in handling and tagging can be cumulative and lethal (Maule and others, 1988; Wedemeyer and others, 1990; Portz and others, 2006), so the goal is to provide the best possible fish care at every step in order to manage the overall effect on study fish.

Use of electricity to sedate Lake Trout for intracoelomic implantation of electronic transmitters

USGS Publications Warehouse

Faust, Matthew D.; Vandergoot, Christopher; Hostnik, Eric T.; Binder, Thomas R.; Mida Hinderer, Julia L.; Ives, Jessica T.; Krueger, Charles C.

2017-01-01

Use of telemetry data to inform fisheries conservation and management is becoming increasingly common; as such, fish typically must be sedated before surgical implantation of transmitters into the coelom. Given that no widely available, immediate-release chemical sedative currently exists in North America, we investigated the feasibility of using electricity to sedate Lake Trout Salvelinus namaycush long enough for an experienced surgeon to implant an electronic transmitter (i.e., 180 s). Specifically, our study objectives were to determine (1) whether some combination of electrical waveform characteristics (i.e., duty cycle, frequency, voltage, and pulse type) could sedate Lake Trout for at least 180 s; and (2) whether Lake Trout that were sequentially exposed to continuous DC and pulsed DC had greater rates of spinal injury and short-term mortality than control fish. A Portable Electrosedation System unit was used to sedate hatchery and wild Lake Trout. Dual-frequency pulsed-DC and two-stage approaches successfully sedated Lake Trout and had similar induction and recovery times. Lake Trout sedated using the two-stage approach did not have survival rates or spinal abnormalities that were significantly different from those of control fish. We concluded that electricity was a viable alternative to chemical sedatives for sedating Lake Trout before surgical implantation of an electronic transmitter, but we suggest that Lake Trout and other closely related species (e.g., Arctic Char Salvelinus alpinus) may require morphotype-specific electrical waveforms due to their morphological diversity.

Potential Interference from Wireless Water Tank Transmitters at Goldstone

NASA Astrophysics Data System (ADS)

Ho, C.

2008-02-01

The Deep Space Network (DSN) facility in the Goldstone, California, area is considering installation of a new type of wireless transmitter (M2400S) within the facility. The transmitters will be used to monitor the water levels in several water tanks. Then these water-level signals will be transmitted to the nearby DSN facilities using transmitters operating in the UHF band (900-MHz) or S-band (2.4-GHz). This study is to evaluate the interference effects from the transmitters in adjacent DSN receiving stations. First we perform a terrain profile analysis to identify if there is a line of sight between each transmitter and the nearby DSN stations. After taking into account terrain shielding using high-resolution data, total propagation losses are calculated along each path. Then we perform the link analysis for each site to identify if the interference power exceeds the protection threshold of DSN receiving stations. As a result, we find that, because there is no bandpass filter installed in the transmitter system, interference power from the new transmitter at S-band will greatly exceed the protection criteria of broadband radio astronomy services (RAS) at S-band, such as Deep Space Station (DSS) 12 and DSS 28, by about 50 dB. The interference may also cause problems on all deep-space research stations at S-band, such as the Mars, Apollo, Venus, and Gemini sites. Without a sharp bandpass filter to suppress the out-of-band emissions in the frequency bands that the DSN station and RAS use, the author recommends not installing this type of transmitter within the Goldstone DSN facility area.

47 CFR 95.639 - Maximum transmitter power.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) No GMRS transmitter, under any condition of modulation, shall exceed: (1) 50 W Carrier power (average... transmitter, under any condition of modulation, shall exceed a carrier power or peak envelope TP (single-sideband only) of: (1) 4 W in the 26-27 MHz frequency band, except on channel frequency 27.255 MHz; (2) 25...

Experimental Realization of Tunable Metamaterial Hyper-transmitter

PubMed Central

Yoo, Young Joon; Yi, Changhyun; Hwang, Ji Sub; Kim, Young Ju; Park, Sang Yoon; Kim, Ki Won; Rhee, Joo Yull; Lee, YoungPak

2016-01-01

We realized the tunable metamaterial hyper-transmitter in the microwave range utilizing simple planar meta-structure. The single-layer metamaterial hyper-transmitter shows that the transmission peak occurs at 14 GHz. In case of the dual-layer one, it is possible to control the transmission peak from 5 to 10 GHz. Moreover, all the transmission peaks reveal transmission over 100%. We experimentally and theoretically investigated these phenomena through 3-dimensional simulation and measurement. The reason for being over 100% is also elucidated. The suggested hyper-transmitter can be used, for example, in enhancing the operating distance of the electromagnetic wave in Wi-Fi, military radar, wireless power transfer and self-driving car. PMID:27629804

Experimental Realization of Tunable Metamaterial Hyper-transmitter

NASA Astrophysics Data System (ADS)

Yoo, Young Joon; Yi, Changhyun; Hwang, Ji Sub; Kim, Young Ju; Park, Sang Yoon; Kim, Ki Won; Rhee, Joo Yull; Lee, Youngpak

2016-09-01

We realized the tunable metamaterial hyper-transmitter in the microwave range utilizing simple planar meta-structure. The single-layer metamaterial hyper-transmitter shows that the transmission peak occurs at 14 GHz. In case of the dual-layer one, it is possible to control the transmission peak from 5 to 10 GHz. Moreover, all the transmission peaks reveal transmission over 100%. We experimentally and theoretically investigated these phenomena through 3-dimensional simulation and measurement. The reason for being over 100% is also elucidated. The suggested hyper-transmitter can be used, for example, in enhancing the operating distance of the electromagnetic wave in Wi-Fi, military radar, wireless power transfer and self-driving car.

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation.

PubMed

Dawes, P M; Vizi, E S

1973-06-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation.2. In the presence of physostigmine, the resting release of acetylcholine was 0.13 +/- 0.01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3.1 +/- 0.4 (pmol/g)/volley in 4 experiments (means +/- S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0.3 Hz.3. Tetrodotoxin, 0.8 muM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5 degrees C reduced to below detectable levels both the resting release and that produced by nerve stimulation.4. The resting release of acetylcholine was increased by a potassium-rich (49.4 mM K(+)) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li(+)).5. (-)-Noradrenaline bitartrate, 3 muM, and (+/-)-adrenaline bitartrate, 1.5 muM, reduced by 70% the output of acetylcholine induced by stimulation at 0.3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine.6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release.

A novel inositol phosphate selectively inhibits vasoconstriction evoked by the sympathetic co-transmitters neuropeptide Y (NPY) and adenosine triphosphate (ATP).

PubMed

Wahlestedt, C; Reis, D J; Yoo, H; Adamsson, M; Andersson, D; Edvinsson, L

1992-08-31

Postganglionic sympathetic nerves release norepinephrine (NE) as their primary neurotransmitter at vascular and other targets. However, much evidence supports involvement of additional messengers, co-transmitters, which are co-released with NE upon sympathetic nerve stimulation and thereby contribute to their actions, e.g., vasoconstriction. Two such putative co-transmitters, neuropeptide Y (NPY) and adenosine triphosphate (ATP) have been of particular interest since they fulfill several neurotransmitter criteria. Importantly, hitherto it has been difficult to antagonize vasoconstriction evoked by either NPY or ATP with agents that are devoid of intrinsic activity. The present study describes the ability of a novel inositol phosphate, D-myo-inositol 1,2,6-trisphosphate (Ins[1,2,6]P3; PP-56) to in vitro potently block vasoconstrictor responses elicited by NPY and ATP, but not by NE, as studied in guinea-pig isolated basilar artery. The action of Ins[1,2,6]P3 does not seem to occur through antagonism at NPY- or ATP-receptor recognition sites, labeled by 125I-peptide YY and 35S-gamma-ATP, respectively, in membranes of rat cultured vena cava vascular smooth muscle cells. However, it does involve inhibition of the influx of Ca2+ induced by either co-transmitter in these same vena cava cells. It is proposed that Ins[1,2,6]P3 may be a useful functional antagonist of non-adrenergic component(s) of the vasoconstrictor response to sympathetic nerve stimulation.

47 CFR 101.131 - Transmitter construction and installation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Transmitter construction and installation. 101.131 Section 101.131 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.131 Transmitter construction and...

47 CFR 101.131 - Transmitter construction and installation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Transmitter construction and installation. 101.131 Section 101.131 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.131 Transmitter construction and...

47 CFR 101.131 - Transmitter construction and installation.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Transmitter construction and installation. 101.131 Section 101.131 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.131 Transmitter construction and...

47 CFR 101.131 - Transmitter construction and installation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Transmitter construction and installation. 101.131 Section 101.131 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.131 Transmitter construction and...

47 CFR 87.91 - Operation of transmitter controls.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operation of transmitter controls. 87.91 Section 87.91 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO.... These operators must not perform any internal adjustment of transmitter frequency determining elements...

Transmitter release modulation by intracellular Ca2+ buffers in facilitating and depressing nerve terminals of pyramidal cells in layer 2/3 of the rat neocortex indicates a target cell-specific difference in presynaptic calcium dynamics

PubMed Central

Rozov, A; Burnashev, N; Sakmann, B; Neher, E

2001-01-01

In connections formed by nerve terminals of layer 2/3 pyramidal cells onto bitufted interneurones in young (postnatal day (P)14–15) rat somatosensory cortex, the efficacy and reliability of synaptic transmission were low. At these connections release was facilitated by paired-pulse stimulation (at 10 Hz). In connections formed by terminals of layer 2/3 pyramids with multipolar interneurones efficacy and reliability were high and release was depressed by paired-pulse stimulation. In both types of terminal, however, the voltage-dependent Ca2+ channels that controlled transmitter release were predominantly of the P/Q- and N-subtypes. The relationship between unitary EPSP amplitude and extracellular calcium concentration ([Ca2+]o) was steeper for facilitating than for depressing terminals. Fits to a Hill equation with nH= 4 indicated that the apparent KD of the Ca2+ sensor for vesicle release was two- to threefold lower in depressing terminals than in facilitating ones. Intracellular loading of pyramidal neurones with the fast and slowly acting Ca2+ buffers BAPTA and EGTA differentially reduced transmitter release in these two types of terminal. Unitary EPSPs evoked by pyramidal cell stimulation in bitufted cells were reduced by presynaptic BAPTA and EGTA with half-effective concentrations of ∼0.1 and ∼1 mm, respectively. Unitary EPSPs evoked in multipolar cells were reduced to one-half of control at higher concentrations of presynaptic BAPTA and EGTA (∼0.5 and ∼7 mm, respectively). Frequency-dependent facilitation of EPSPs in bitufted cells was abolished by EGTA at concentrations of > 0.2 mm, suggesting that accumulation of free Ca2+ is essential for facilitation in the terminals contacting bitufted cells. In contrast, facilitation was unaffected or even slightly increased in the terminals loaded with BAPTA in the concentration range 0.02–0.5 mm. This is attributed to partial saturation of exogenously added BAPTA. However, BAPTA at concentrations > 1 mm

Transmitter Pulse Estimation and Measurements for Airborne TDEM Systems

NASA Astrophysics Data System (ADS)

Vetrov, A.; Mejzr, I.

2013-12-01

The processing and interpretation of Airborne Time Domain EM data requires precise description of the transmitter parameters, including shape, amplitude and length of the transmitted pulse. There are several ways to measure pulse shape of the transmitter loop. Transmitted pulse can be recorded by a current monitor installed on the loop. The current monitor readings do not give exact image due to own time-domain physical characteristics of the current monitor. Another way is to restore the primary pulse shape from the receiver data recorded on-time, if such is possible. The receiver gives exact image of the primary field projection combined with the ground response, which can be minimized at high altitude pass, usually with a transmitter elevation higher than 1500 ft from the ground. The readings on the receiver are depending on receiver position and orientation. Modeling of airborne TDEM transmitter pulse allows us to compare estimated and measured shape of the pulse and apply required corrections. Airborne TDEM system transmitter pulse shape has been studied by authors while developing P-THEM system. The data has been gathered during in-doors and out-doors ground tests in Canada, as well as during flight tests in Canada and in India. The P-THEM system has three-axes receiver that is suspended on a tow-cable in the midpoint between the transmitter and the helicopter. The P-THEM receiver geometry does not require backing coils to dump the primary field. The system records full-wave data from the receiver and current monitor installed on the transmitter loop, including on-time and off-time data. The modeling of the transmitter pulse allowed us to define the difference between estimated and measured values. The higher accuracy pulse shape can be used for better data processing and interpretation. A developed model can be applied to similar systems and configurations.

47 CFR 73.515 - NCE FM transmitter location.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false NCE FM transmitter location. 73.515 Section 73.515 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Noncommercial Educational FM Broadcast Stations § 73.515 NCE FM transmitter location. The...

47 CFR 73.515 - NCE FM transmitter location.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false NCE FM transmitter location. 73.515 Section 73.515 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Noncommercial Educational FM Broadcast Stations § 73.515 NCE FM transmitter location. The...

Acetylcholine is released from taste cells, enhancing taste signalling

PubMed Central

Dando, Robin; Roper, Stephen D

2012-01-01

Acetylcholine (ACh), a candidate neurotransmitter that has been implicated in taste buds, elicits calcium mobilization in Receptor (Type II) taste cells. Using RT-PCR analysis and pharmacological interventions, we demonstrate that the muscarinic acetylcholine receptor M3 mediates these actions. Applying ACh enhanced both taste-evoked Ca2+ responses and taste-evoked afferent neurotransmitter (ATP) secretion from taste Receptor cells. Blocking muscarinic receptors depressed taste-evoked responses in Receptor cells, suggesting that ACh is normally released from taste cells during taste stimulation. ACh biosensors confirmed that, indeed, taste Receptor cells secrete acetylcholine during gustatory stimulation. Genetic deletion of muscarinic receptors resulted in significantly diminished ATP secretion from taste buds. The data demonstrate a new role for acetylcholine as a taste bud transmitter. Our results imply specifically that ACh is an autocrine transmitter secreted by taste Receptor cells during gustatory stimulation, enhancing taste-evoked responses and afferent transmitter secretion. PMID:22570381

47 CFR 61.33 - Letters of transmittal.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Rules for Dominant Carriers § 61.33 Letters of transmittal. (a) Except as specified in § 61.32(b), all... with Number 1, and must be accompanied by a letter of transmittal, A4 (21 cm×29.7 cm) or 81/2 by 11... purpose of the filing; (2) Specify whether supporting information under § 61.38 is required; (3) State...

Design Parameters of a Miniaturized Piezoelectric Underwater Acoustic Transmitter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Huidong; Deng, Zhiqun; Yuan, Yong

2012-07-02

The Juvenile Salmon Acoustic Telemetry System (JSATS) project supported by the U.S. Army Corps of Engineers, Portland District, has yielded the smallest acoustic fish tag transmitter commercially available to date. In order to study even smaller fish populations and make the transmitter injectable by needles, the JSATS acoustic micro transmitter needs to be further downsized. As part of the transmitter downsizing effort some of the design parameters of the lead zirconate titanate (PZT) ceramic tube transducer in the transmitter were studied, including the type of PZT, the backing material, the necessary drive voltage, the transmitting bandwidth and the length ofmore » the transducer. It was found that, to satisfy the 156-dB source level requirement of JSATS, a square wave with a 10-volt amplitude is required to drive 'soft' PZT transducers. PZT-5H demonstrated the best source level performance. For Navy types I and II, 16 volts or 18 volts were needed. Ethylene-propylene-diene monomer (EPDM) closed-cell foam was found to be the backing material providing the highest source level. The effect of tube length on the source level is also demonstrated in this paper, providing quantitative information for downsizing of small piezoelectric transmitters.« less

The effect of imiquimod on taste bud calcium transients and transmitter secretion

PubMed Central

Wu, Sandy Y

2016-01-01

Background and Purpose Imiquimod is an immunomodulator approved for the treatment of basal cell carcinoma and has adverse side effects, including taste disturbances. Paracrine transmission, representing cell–cell communication within taste buds, has the potential to shape the final signals that taste buds transmit to the brain. Here, we tested the underlying assumption that imiquimod modifies taste transmitter secretion in taste buds of mice. Experimental Approach Taste buds were isolated from C57BL/6J mice. The effects of imiquimod on transmitter release in taste buds were measured using calcium imaging with cellular biosensors, and examining the net effect of imiquimod on taste‐evoked ATP secretion from mouse taste buds. Key Results Up to 72% of presynaptic (Type III) taste cells responded to 100 μM imiquimod with an increase in intracellular Ca2+ concentrations. These Ca2 + responses were inhibited by thapsigargin, an inhibitor of the sarco/endoplasmic reticulum Ca2 +‐ATPase, and by U73122, a PLC inhibitor, suggesting that the Ca2 + mobilization elicited by imiquimod was dependent on release from internal Ca2 + stores. Moreover, combining studies of Ca2 + imaging with cellular biosensors showed that imiquimod evoked secretion of 5‐HT, which then provided negative feedback onto receptor (Type II) cells to reduce taste‐evoked ATP secretion. Conclusion and Implications Our results provide evidence that there is a subset of taste cells equipped with a range of intracellular mechanisms that respond to imiquimod. The findings are also consistent with a role of imiquimod as an immune response modifier, which shapes peripheral taste responses via 5‐HT signalling. PMID:27464850

Discussion on informatization teaching of certain radar transmitter

NASA Astrophysics Data System (ADS)

Liang, Guanhui; Lv, Guizhou; Meng, Yafeng

2017-04-01

With the development of informatization, the traditional teaching method of certain radar transmitter is more and more difficult to meet the need of cultivating new type of high-quality military talents. This paper first analyzes the problems traditional teaching method of certain radar transmitter, and then puts forward the strategy of informatization teaching, and finally elaborates the concrete steps and contents of informatization teaching. Using the multimedia maintenance training system, information simulation training system and network courses and other informatization means, effectively improves the master degree to radar transmitter by trainees, but also lays a good foundation for repair in the next step.

alpha2-Adrenoceptors control the release of noradrenaline but not neuropeptide Y from perivascular nerve terminals.

PubMed

Donoso, M Veronica; Carvajal, Andrés; Paredes, Alfonso; Tomic, Alexander; Koenig, Cecilia S; Huidobro-Toro, J Pablo

2002-09-01

Neuropeptide Y (NPY) and noradrenaline (NA) are co-transmitters at many sympathetic synapses, but it is not yet clear if their release is independently regulated. To address this question, we quantified the electrically evoked release of these co-transmitters from perivascular nerve terminals to the mesenteric circulation in control and drug-treated rats. 6-Hydroxydopamine reduced the tissue content and the electrically evoked release of ir-NPY and NA as well as the rise in perfusion pressure. A 0.001 mg/kg reserpine reduced the content of ir-NPY and NA, but did not modify their release nor altered the rise in perfusion pressure elicited by the electrical stimuli. However, 0.1mg/kg reserpine reduced both the content and release of NA but decreased only the content but not the release of ir-NPY; the rise in perfusion pressure was halved. Clonidine did not affect the release of ir-NPY while it lowered the outflow of NA, not altering the rise in perfusion pressure elicited by the electrical stimuli. Yohimbine, did not modify the release of ir-NPY but increased the NA outflow, it antagonized the clonidine effect. Therefore, presynaptic alpha2-adrenoceptors modulate the release of NA but not NPY, implying separate regulatory mechanisms.

UWB transmitter

DOEpatents

Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Romero, Carlos E.

2013-01-15

An ultra-wideband (UWB) dual impulse transmitter is made up of a trigger edge selection circuit actuated by a single trigger input pulse; a first step recovery diode (SRD) based pulser connected to the trigger edge selection circuit to generate a first impulse output; and a second step recovery diode (SRD) based pulser connected to the trigger edge selection circuit in parallel to the first pulser to generate a second impulse output having a selected delay from the first impulse output.

47 CFR 95.621 - GMRS transmitter channel frequencies.

Code of Federal Regulations, 2010 CFR

2010-10-01

... only for certain station classes and station locations. See part 95, subpart A. (b) Each GMRS transmitter for mobile station, small base station and control station operation must be maintained within a frequency tolerance of 0.0005%. Each GMRS transmitter for base station (except small base), mobile relay...

47 CFR 101.131 - Transmitter construction and installation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... by the licensee. (b) In any case where the maximum modulating frequency of a transmitter is prescribed by the Commission, the transmitter must be equipped with a low-pass or band-pass modulation filter of suitable performance characteristics. In those cases where a modulation limiter is employed, the...

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation

PubMed Central

Dawes, P. M.; Vizi, E. S.

1973-01-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation. 2. In the presence of physostigmine, the resting release of acetylcholine was 0·13 ± 0·01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3·1 ± 0·4 (pmol/g)/volley in 4 experiments (means ± S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0·3 Hz. 3. Tetrodotoxin, 0·8 μM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5° C reduced to below detectable levels both the resting release and that produced by nerve stimulation. 4. The resting release of acetylcholine was increased by a potassium-rich (49·4 mM K+) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li+). 5. (-)-Noradrenaline bitartrate, 3 μM, and (±)-adrenaline bitartrate, 1·5 μM, reduced by 70% the output of acetylcholine induced by stimulation at 0·3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine. 6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release. PMID:4733726

Effects of external radio transmitters on fish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, M.J.; McCormick, J.H.

1981-04-01

Yellow perch (Perca flavescens) and largemouth bass (Micropterus salmoides) were studied to determine the effects of externally attached radio transmitter tags. Perch that had been tagged with dummy radio tags were more susceptible to predation and more sensitive to environmental stress than were controls. Feeding and respiration rates were similar among dummy tagged and control groups of perch over a 6-week period. The feeding rate of dummy tagged largemouth bass was lower than that of untagged fish over a 3,5-week period. On the basis of these studies, we conclude that weights of external transmitters in water should be less thanmore » 1.5% of the fish weight. Design considerations should include streamlining components and an anterior attachment wire at the extreme leading edge of an external transmitter to prevent entanglement of the tag in surrounding vegetation.« less

Controlled release of betamethasone from vitamin E-loaded silicone-based soft contact lenses.

PubMed

Rad, Maryam Shayani; Sajadi Tabassi, Sayyed Abolghasem; Moghadam, Maryam Hassanpour; Mohajeri, Seyed Ahmad

2016-11-01

Betamethasone (BMZ) is an effective drug which is commonly used as an eye drop for the management of ophthalmic inflammations. Due to low ocular bioavailability, it is necessary to prepare and optimize an ocular drug delivery system for BMZ. In this study we tried to use vitamin E diffusion barrier for sustaining BMZ release. Three commercial contact lenses were soaked in vitamin E solutions and swelling percentage, diameter, transmittance, binding capacity and release amount and time were evaluated in comparison with non-vitamin E-loaded pure lenses. The results showed that vitamin E significantly decreased water content of contact lenses whereas, increased the lens diameter in both dry and wet states. It effectively blocked UV radiation which is harmful for the eye surface while had no significant effect on visible transmittance. BMZ loading capacity enhanced and release rate remarkably decreased after using vitamin E as a hydrophobic diffusion barrier. This study revealed that vitamin E can be applied as a hydrophobic diffusion barrier for controlling and sustaining BMZ release from silicone-based soft contact lenses into the lachrymal fluid. It can also protect eye tissues as an antioxidant by blocking the UV radiation.

Optical Tunable-Based Transmitter for Multiple Radio Frequency Bands

NASA Technical Reports Server (NTRS)

Nguyen, Hung (Inventor); Simons, Rainee N. (Inventor); Wintucky, Edwin G. (Inventor); Freeman, Jon C. (Inventor)

2016-01-01

An optical tunable transmitter is used to transmit multiple radio frequency bands on a single beam. More specifically, a tunable laser is configured to generate a plurality of optical wavelengths, and an optical tunable transmitter is configured to modulate each of the plurality of optical wavelengths with a corresponding radio frequency band. The optical tunable transmitter is also configured to encode each of the plurality of modulated optical wavelengths onto a single laser beam for transmission of a plurality of radio frequency bands using the single laser beam.

Leaf bidirectional reflectance and transmittance in corn and soybean

NASA Technical Reports Server (NTRS)

Walter-Shea, E. A.; Norman, J. M.; Blad, B. L.

1989-01-01

Bidirectional optical properties of leaves must be adequately characterized to develop comprehensive and reliably predictive canopy radiative-transfer models. Directional reflectance and transmittance factors of individual corn and soybean leaves were measured at source incidence angles (SIAs) 20, 45, and 70 deg and numerous view angles in the visible and NIR. Bidirectional reflectance distributions changed with increasing SIA, with forward scattering most pronounced at 70 deg. Directional-hemispherical reflectance generally increased and transmittance decreased with increased SIA. Directional-hemispherical reflectance factors were higher and transmittances were lower than the nadir-viewed reflectance component.

Effect of relative volume on radio transmitter expulsion in subadult common carp

USGS Publications Warehouse

Penne, C.R.; Ahrens, N.L.; Summerfelt, R.C.; Pierce, C.L.

2007-01-01

Expulsion of surgically implanted radio transmitters is a problem in some fish telemetry studies. We conducted a 109-d experiment to test the hypothesis that variation in relative volume of transmitters surgically implanted in subadult common carp Cyprinus carpio would affect transmitter expulsion. We also necropsied fish at the end of the experiment to evaluate histological evidence for the mechanism of expulsion. Survival rate was high during our experiment; all control fish and 88% of the fish subjected to the implantation surgery survived. Expulsion rate was low; of the 23 fish that received transmitters and survived the experiment, only two (9%) expelled the transmitters. One of these expulsions occurred through a rupture of the incision and the other occurred via the intestine. Retained transmitters were all encapsulated by tissue, and most exhibited multiple adhesions to the intestine, gonads, and body wall. Adhesions were more numerous in fish that received larger transmitters. ?? Copyright by the American Fisheries Society 2007.

The Geoscience Laser Altimeter System (GLAS) Laser Transmitter

NASA Technical Reports Server (NTRS)

Afzal, Robert S.; Yu, Anthony W.; Dallas, Joseph L.; Melak, Anthony; Lukemir, Alan; Ramos-Izqueirdo, L.; Mamakos, William

2007-01-01

The Geoscience Laser Altimeter System (GLAS), launched in January 2003, is a laser altimeter and lidar for the Earth Observing System's (EOS) ICESat mission. GLAS accommodates three, sequentially operated, diode-pumped, solid-state, Nd:YAG laser transmitters. The laser transmitter requirements, design and qualification test results for this space-based remote sensing instrument is summarized and presented

BioRadioTransmitter: a self-powered wireless glucose-sensing system.

PubMed

Hanashi, Takuya; Yamazaki, Tomohiko; Tsugawa, Wakako; Ikebukuro, Kazunori; Sode, Koji

2011-09-01

Although an enzyme fuel cell can be utilized as a glucose sensor, the output power generated is too low to power a device such as a currently available transmitter and operating system, and an external power source is required for operating an enzyme-fuel-cell-based biosensing system. We proposed a novel biosensor that we named BioCapacitor, in which a capacitor serves as a transducer. In this study, we constructed a new BioCapacitor-based system with an added radio-transmitter circuit and a miniaturized enzyme fuel cell. A miniaturized direct-electron-transfer-type compartmentless enzyme fuel cell was constructed with flavin adenine dinucleotide-dependent glucose dehydrogenase complex-based anode and a bilirubin-oxidase-based cathode. For construction of a BioRadioTransmitter wireless sensing system, a capacitor, an ultra-low-voltage charge-pump-integrated circuit, and Hartley oscillator circuit were connected to the miniaturized enzyme fuel cell. A radio-receiver circuit, comprising two field-effect transistors and a coil as an antenna, was used to amplify the signal generated from the biofuel cells. Radio wave signals generated by the BioRadioTransmitter were received, amplified, and converted from alternate to direct current by the radio receiver. When the capacitor discharges in the presence of glucose, the BioRadioTransmitter generates a radio wave, which is monitored by a radio receiver connected wirelessly to the sensing device. Magnitude of the radio wave transmission frequency change observed at the radio receiver was correlated to glucose concentration in the fuel cells. We constructed a stand-alone, self-powered, wireless glucose-sensing system called a BioRadioTransmitter by using a radio transmitter in which the radio wave transmission frequency changes with the glucose concentration in the fuel cell. The BioRadioTransmitter is a significant advance toward construction of an implantable continuous glucose monitor. © 2011 Diabetes Technology Society.

Evidence for recycling of synaptic vesicle membrane during transmitter release at the frog neuromuscular junction.

PubMed

Heuser, J E; Reese, T S

1973-05-01

When the nerves of isolated frog sartorius muscles were stimulated at 10 Hz, synaptic vesicles in the motor nerve terminals became transiently depleted. This depletion apparently resulted from a redistribution rather than disappearance of synaptic vesicle membrane, since the total amount of membrane comprising these nerve terminals remained constant during stimulation. At 1 min of stimulation, the 30% depletion in synaptic vesicle membrane was nearly balanced by an increase in plasma membrane, suggesting that vesicle membrane rapidly moved to the surface as it might if vesicles released their content of transmitter by exocytosis. After 15 min of stimulation, the 60% depletion of synaptic vesicle membrane was largely balanced by the appearance of numerous irregular membrane-walled cisternae inside the terminals, suggesting that vesicle membrane was retrieved from the surface as cisternae. When muscles were rested after 15 min of stimulation, cisternae disappeared and synaptic vesicles reappeared, suggesting that cisternae divided to form new synaptic vesicles so that the original vesicle membrane was now recycled into new synaptic vesicles. When muscles were soaked in horseradish peroxidase (HRP), this tracerfirst entered the cisternae which formed during stimulation and then entered a large proportion of the synaptic vesicles which reappeared during rest, strengthening the idea that synaptic vesicle membrane added to the surface was retrieved as cisternae which subsequently divided to form new vesicles. When muscles containing HRP in synaptic vesicles were washed to remove extracellular HRP and restimulated, HRP disappeared from vesicles without appearing in the new cisternae formed during the second stimulation, confirming that a one-way recycling of synaptic membrane, from the surface through cisternae to new vesicles, was occurring. Coated vesicles apparently represented the actual mechanism for retrieval of synaptic vesicle membrane from the plasma membrane

EVIDENCE FOR RECYCLING OF SYNAPTIC VESICLE MEMBRANE DURING TRANSMITTER RELEASE AT THE FROG NEUROMUSCULAR JUNCTION

PubMed Central

Heuser, J. E.; Reese, T. S.

1973-01-01

When the nerves of isolated frog sartorius muscles were stimulated at 10 Hz, synaptic vesicles in the motor nerve terminals became transiently depleted. This depletion apparently resulted from a redistribution rather than disappearance of synaptic vesicle membrane, since the total amount of membrane comprising these nerve terminals remained constant during stimulation. At 1 min of stimulation, the 30% depletion in synaptic vesicle membrane was nearly balanced by an increase in plasma membrane, suggesting that vesicle membrane rapidly moved to the surface as it might if vesicles released their content of transmitter by exocytosis. After 15 min of stimulation, the 60% depletion of synaptic vesicle membrane was largely balanced by the appearance of numerous irregular membrane-walled cisternae inside the terminals, suggesting that vesicle membrane was retrieved from the surface as cisternae. When muscles were rested after 15 min of stimulation, cisternae disappeared and synaptic vesicles reappeared, suggesting that cisternae divided to form new synaptic vesicles so that the original vesicle membrane was now recycled into new synaptic vesicles. When muscles were soaked in horseradish peroxidase (HRP), this tracerfirst entered the cisternae which formed during stimulation and then entered a large proportion of the synaptic vesicles which reappeared during rest, strengthening the idea that synaptic vesicle membrane added to the surface was retrieved as cisternae which subsequently divided to form new vesicles. When muscles containing HRP in synaptic vesicles were washed to remove extracellular HRP and restimulated, HRP disappeared from vesicles without appearing in the new cisternae formed during the second stimulation, confirming that a one-way recycling of synaptic membrane, from the surface through cisternae to new vesicles, was occurring. Coated vesicles apparently represented the actual mechanism for retrieval of synaptic vesicle membrane from the plasma membrane

47 CFR 22.507 - Number of transmitters per station.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 2 2014-10-01 2014-10-01 false Number of transmitters per station. 22.507 Section 22.507 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.507 Number of transmitters per station...

47 CFR 22.507 - Number of transmitters per station.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Number of transmitters per station. 22.507 Section 22.507 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.507 Number of transmitters per station...

47 CFR 22.507 - Number of transmitters per station.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 2 2011-10-01 2011-10-01 false Number of transmitters per station. 22.507 Section 22.507 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.507 Number of transmitters per station...

47 CFR 22.507 - Number of transmitters per station.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 2 2013-10-01 2013-10-01 false Number of transmitters per station. 22.507 Section 22.507 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.507 Number of transmitters per station...

Effects of radio transmitters on the behavior of Red-headed Woodpeckers

Treesearch

Mark Vukovich; John C. Kilgo

2009-01-01

Previous studies have revealed that radio-transmitters may affect bird behaviors, including feeding rates, foraging behavior, vigilance, and preening behavior. In addition, depending on the method of attachment, transmitters can potentially affect the ability of cavity-nesting birds to use cavities. Our objective was to evaluate effects of transmitters on the behavior...

47 CFR 73.4108 - FM transmitter site map submissions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false FM transmitter site map submissions. 73.4108 Section 73.4108 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4108 FM transmitter site map...

Calibrating acoustic acceleration transmitters for estimating energy use by wild adult Pacific salmon.

PubMed

Wilson, S M; Hinch, S G; Eliason, E J; Farrell, A P; Cooke, S J

2013-03-01

This study is the first to calibrate acceleration transmitters with energy expenditure using a vertebrate model species. We quantified the relationship between acoustic accelerometer output and oxygen consumption across a range of swim speeds and water temperatures for Harrison River adult sockeye salmon (Oncorhynchus nerka). First, we verified that acceleration transmitters with a sampling frequency of 10 Hz could be used as a proxy for movement in sockeye salmon. Using a mixed effects model, we determined that tailbeat frequency and acceleration were positively correlated (p<0.0001), independent of tag ID. Acceleration (p<0.0001) was positively related to swim speed while fork length (p=0.051) was negatively related to swim speed. Oxygen consumption and accelerometer output (p<0.0001) had a positive linear relationship and were temperature dependent (p<0.0001). There were no differences in swim performance (F(2,12)=1.023, p=0.820) or oxygen consumption (F(1,12)=0.054, p=0.332) between tagged and untagged individuals. Five tagged fish were released into the Fraser River estuary and manually tracked. Of the five fish, three were successfully tracked for 1h. The above relationships were used to determine that the average swim speed was 1.25±0.03 body lengths s(-1) and cost of transport was 3.39±0.17 mg O(2) kg(-1)min(-1), averaged across the three detected fish. Acceleration transmitters can be effectively used to remotely evaluate fine-scale behavior and estimate energy consumption of adult Pacific salmon throughout their homeward spawning migration. Copyright © 2012 Elsevier Inc. All rights reserved.

Transmittance and Tunneling Current through a Trapezoidal Barrier under Spin Polarization Consideration

NASA Astrophysics Data System (ADS)

Noor, F. A.; Nabila, E.; Mardianti, H.; Ariani, T. I.; Khairurrijal

2018-04-01

The transmittance and tunneling current in heterostructures under spin polarization consideration were studied by employing a zinc-blended structure for the heterostructures. An electron tunnels through a potential barrier by applying a bias voltage to the barrier, which is called the trapezoidal potential barrier. In order to study the transmittance, an Airy wave function approach was employed to find the transmittance. The obtained transmittance was then utilized to compute the tunneling current by using a Gauss quadrature method. It was shown that the transmittances were asymmetric with the incident angle of the electron. It was also shown that the tunneling currents increased as the bias voltage increased.

47 CFR 95.647 - FRS unit and R/C transmitter antennas.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false FRS unit and R/C transmitter antennas. 95.647... transmitter antennas. The antenna of each FRS unit, and the antenna of each R/C station transmitting in the 72-76 MHz band, must be an integral part of the transmitter. The antenna must have no gain (as compared...

47 CFR 95.647 - FRS unit and R/C transmitter antennas.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false FRS unit and R/C transmitter antennas. 95.647... transmitter antennas. The antenna of each FRS unit, and the antenna of each R/C station transmitting in the 72-76 MHz band, must be an integral part of the transmitter. The antenna must have no gain (as compared...

47 CFR 95.647 - FRS unit and R/C transmitter antennas.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false FRS unit and R/C transmitter antennas. 95.647... transmitter antennas. The antenna of each FRS unit, and the antenna of each R/C station transmitting in the 72-76 MHz band, must be an integral part of the transmitter. The antenna must have no gain (as compared...

47 CFR 95.647 - FRS unit and R/C transmitter antennas.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false FRS unit and R/C transmitter antennas. 95.647... transmitter antennas. The antenna of each FRS unit, and the antenna of each R/C station transmitting in the 72-76 MHz band, must be an integral part of the transmitter. The antenna must have no gain (as compared...

47 CFR 95.647 - FRS unit and R/C transmitter antennas.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false FRS unit and R/C transmitter antennas. 95.647... transmitter antennas. The antenna of each FRS unit, and the antenna of each R/C station transmitting in the 72-76 MHz band, must be an integral part of the transmitter. The antenna must have no gain (as compared...

Modified method for external attachment of transmitters to birds using two subcutaneous anchors

USGS Publications Warehouse

Lewis, T.L.; Flint, Paul L.

2008-01-01

Of the transmitter attachment techniques for birds, the subcutaneous anchor provides a secure attachment that yields relatively few secondary effects. However, the use of subcutaneous anchors has been limited by transmitter size and retention time. Using a modified method of attachment that utilized two subcutaneous anchors, we deployed 69 GPS transmitters, plus 13 VHF transmitters that were similar in size and weight to GPS models, on Pacific Black Brant (Branta bernicla nigricans). Prior to our study, only harnesses were used for attaching GPS transmitters on birds, mainly because GPS transmitters are too large for other external attachment techniques and implantation in the body cavity attenuates the GPS signal. Thus, to increase the size capacity of anchor attachment and to avoid the well-documented negative effects of harnesses on behavior and survival, we added a second anchor at the transmitter's posterior end. The double-anchor attachment technique was quickly and easily accomplished in the field, requiring bird handling times of <10 min. Incidental recoveries of tagged Brant indicate a high degree of transmitter retention. Five recaptured birds (4-6 weeks after deployment) and eight killed by hunters (3-6 mo after deployment) retained their GPS transmitters. For studies involving the use of relatively large transmitters, the double-anchor method appears to provide a viable alternative for external attachment. ?? 2008 Association of Field Ornithologists.

Identification of unique release kinetics of serotonin from guinea-pig and human enterochromaffin cells

PubMed Central

Raghupathi, Ravinarayan; Duffield, Michael D; Zelkas, Leah; Meedeniya, Adrian; Brookes, Simon J H; Sia, Tiong Cheng; Wattchow, David A; Spencer, Nick J; Keating, Damien J

2013-01-01

The major source of serotonin (5-HT) in the body is the enterochromaffin (EC) cells lining the intestinal mucosa of the gastrointestinal tract. Despite the fact that EC cells synthesise ∼95% of total body 5-HT, and that this 5-HT has important paracrine and endocrine roles, no studies have investigated the mechanisms of 5-HT release from single primary EC cells. We have developed a rapid primary culture of guinea-pig and human EC cells, allowing analysis of single EC cell function using electrophysiology, electrochemistry, Ca2+ imaging, immunocytochemistry and 3D modelling. Ca2+ enters EC cells upon stimulation and triggers quantal 5-HT release via L-type Ca2+ channels. Real time amperometric techniques reveal that EC cells release 5-HT at rest and this release increases upon stimulation. Surprisingly for an endocrine cell storing 5-HT in large dense core vesicles (LDCVs), EC cells release 70 times less 5-HT per fusion event than catecholamine released from similarly sized LDCVs in endocrine chromaffin cells, and the vesicle release kinetics instead resembles that observed in mammalian synapses. Furthermore, we measured EC cell density along the gastrointestinal tract to create three-dimensional (3D) simulations of 5-HT diffusion using the minimal number of variables required to understand the physiological relevance of single cell 5-HT release in the whole-tissue milieu. These models indicate that local 5-HT levels are likely to be maintained around the activation threshold for mucosal 5-HT receptors and that this is dependent upon stimulation and location within the gastrointestinal tract. This is the first study demonstrating single cell 5-HT release in primary EC cells. The mode of 5-HT release may represent a unique mode of exocytosis amongst endocrine cells and is functionally relevant to gastrointestinal sensory and motor function. PMID:24099799

13. View of southerly side of transmitter building no. 101 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. View of southerly side of transmitter building no. 101 from south, showing tracking radar (tr) on top of transmitter building no. 102 in background left and abandoned radome on top of transmitter building no. 101 in middle of photograph with utilidor passageway link to right of photograph. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Distributed Localization of Active Transmitters in a Wireless Sensor Network

DTIC Science & Technology

2012-03-01

Distributed Localization of Active Transmitters in a Wireless Sensor Network THESIS Oba L. Vincent, 2nd Lieutenant, USAF AFIT/GE/ENG/12-41 DEPARTMENT...protection in the United States. AFIT/GE/ENG/12-41 Distributed Localization of Active Transmitters in a Wireless Sensor Network THESIS Presented to the...Transmitters in a Wireless Sensor Network Oba L. Vincent, B.S.E.E. 2nd Lieutenant, USAF Approved: /signed/ 29 Feb 2012 Maj. Mark D. Silvius, Ph.D. (Chairman

Surgical and immediate postrelease mortality of harlequin ducks (Histrionicus histrionicus) implanted with abdominal radio transmitters with percutaneous antennae

USGS Publications Warehouse

Mulcahy, Daniel M.; Esler, Daniel N.

1999-01-01

Radiotelemetry is an essential tool in the study of free-ranging bird populations, and a variety of transmitter-attachment methods have been developed. A promising new method is abdominal implantation of a transmitter with a percutaneous antenna. Researchers using this technique should be concerned about and aware of mortality during surgery and during the immediate postrelease period (the 14-day period following surgery). Of 307 radio-implant surgeries performed between 1995 and 1997 in harlequin ducks (Histrionicus histrionicus), 7 (2.3%) deaths were documented during surgery or anesthetic recovery. Of 295 birds released with implanted radios, 10 (3.4%) died during the immediate postrelease period. Modifications to anesthetic procedures used in the 204 surgeries performed in 1996 and 1997 reduced mortality to 1.5% during surgery and 1.5% during the immediate postrelease period. Anesthetic modifications included intubation of all birds, placement of birds on an elevated platform that allowed the head to rest at a level lower than the body during surgery, placement of a heated water blanket under the birds during surgery, monitoring of body temperature, and use of electrocardiogram and Doppler ultrasound to monitor heart rates and arrhythmias. Low levels of mortality associated with abdominal implantation of radio transmitters may be unavoidable, but mortality can be minimized with adjustments to anesthetic technique.

Project Echo: 960-Megacycle, 10-Kilowatt Transmitter

NASA Technical Reports Server (NTRS)

Schafer, J. P.; Brandt, R. H.

1961-01-01

A 10-kw transmitter operating at 960 to 961 Mc was used at the eastern terminus of the Project Echo communications experiment. This transmitter is located on Crawford's Hill near Holmdel, New Jersey. The 10-kw output feeds into a waveguide line leading to a 60-foot dish antenna. Exciter-driver units are available to drive the power amplifier with various modulations, such as wide-deviation FM, low-index phase modulation, single-sideband or double-sideband modulation with or without carrier, 960.05 or 961.05 Mc constant-frequency CW, and radar on-off pulses at 961.05 Mc. The main output amplifier consists primarily of a four-stage, externally-tuned-cavity, water-cooled klystron, operating at a beam voltage of 16 to 18 kv. The transmitter has been operated during many Moonbounce, tropospheric scatter, and Echo I tests with very satisfactory results. This paper describes its use before March 1, 1961.

Activity-dependent regulation of release probability at excitatory hippocampal synapses: a crucial role of FMRP in neurotransmission

PubMed Central

Wang, Xiao-Sheng; Peng, Chun-Zi; Cai, Wei-Jun; Xia, Jian; Jin, Daozhong; Dai, Yuqiao; Luo, Xue-Gang; Klyachko, Vitaly A.; Deng, Pan-Yue

2014-01-01

Transcriptional silencing of the Fmr1 gene encoding fragile X mental retardation protein (FMRP) causes Fragile X Syndrome (FXS), the most common form of inherited intellectual disability and the leading genetic cause of autism. FMRP has been suggested to play important roles in regulating neurotransmission and short-term synaptic plasticity at excitatory hippocampal and cortical synapses. However, the origins and the mechanisms of these FMRP actions remain incompletely understood, and the role of FMRP in regulating synaptic release probability and presynaptic function remains debated. Here we used variance-mean analysis and peak scaled nonstationary variance analysis to examine changes in both pre- and postsynaptic parameters during repetitive activity at excitatory CA3-CA1 hippocampal synapses in a mouse model of FXS. Our analyses revealed that loss of FMRP did not affect the basal release probability or basal synaptic transmission, but caused an abnormally elevated release probability specifically during repetitive activity. These abnormalities were not accompanied by changes in EPSC kinetics, quantal size or postsynaptic AMPA receptor conductance. Our results thus indicate that FMRP regulates neurotransmission at excitatory hippocampal synapses specifically during repetitive activity via modulation of release probability in a presynaptic manner. Our study suggests that FMRP function in regulating neurotransmitter release is an activity-dependent phenomenon that may contribute to the pathophysiology of FXS. PMID:24646437

47 CFR 73.685 - Transmitter location and antenna system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 4 2013-10-01 2013-10-01 false Transmitter location and antenna system. 73.685... RADIO BROADCAST SERVICES Television Broadcast Stations § 73.685 Transmitter location and antenna system... and antenna height above average terrain employed, the following minimum field strength in dB above...

47 CFR 73.685 - Transmitter location and antenna system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false Transmitter location and antenna system. 73.685... RADIO BROADCAST SERVICES Television Broadcast Stations § 73.685 Transmitter location and antenna system... and antenna height above average terrain employed, the following minimum field strength in dB above...

47 CFR 73.685 - Transmitter location and antenna system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 4 2014-10-01 2014-10-01 false Transmitter location and antenna system. 73.685... RADIO BROADCAST SERVICES Television Broadcast Stations § 73.685 Transmitter location and antenna system... and antenna height above average terrain employed, the following minimum field strength in dB above...

47 CFR 73.685 - Transmitter location and antenna system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 4 2012-10-01 2012-10-01 false Transmitter location and antenna system. 73.685... RADIO BROADCAST SERVICES Television Broadcast Stations § 73.685 Transmitter location and antenna system... and antenna height above average terrain employed, the following minimum field strength in dB above...

47 CFR 73.685 - Transmitter location and antenna system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Transmitter location and antenna system. 73.685... RADIO BROADCAST SERVICES Television Broadcast Stations § 73.685 Transmitter location and antenna system... and antenna height above average terrain employed, the following minimum field strength in dB above...

The novel protein kinase C epsilon isoform modulates acetylcholine release in the rat neuromuscular junction.

PubMed

Obis, Teresa; Hurtado, Erica; Nadal, Laura; Tomàs, Marta; Priego, Mercedes; Simon, Anna; Garcia, Neus; Santafe, Manel M; Lanuza, Maria A; Tomàs, Josep

2015-12-01

Various protein kinase C (PKC) isoforms contribute to the phosphorylating activity that modulates neurotransmitter release. In previous studies we showed that nPKCε is confined in the presynaptic site of the neuromuscular junction and its presynaptic function is activity-dependent. Furthermore, nPKCε regulates phorbol ester-induced acetylcholine release potentiation, which further indicates that nPKCε is involved in neurotransmission. The present study is designed to examine the nPKCε involvement in transmitter release at the neuromuscular junction. We use the specific nPKCε translocation inhibitor peptide εV1-2 and electrophysiological experiments to investigate the involvement of this isoform in acetylcholine release. We observed that nPKCε membrane translocation is key to the synaptic potentiation of NMJ, being involved in several conditions that upregulate PKC isoforms coupling to acetylcholine (ACh) release (incubation with high Ca(2+), stimulation with phorbol esters and protein kinase A, stimulation with adenosine 3',5'-cyclic monophosphorothioate, 8-Bromo-, Rp-isomer, sodium salt -Sp-8-BrcAMP-). In all these conditions, preincubation with the nPKCε translocation inhibitor peptide (εV1-2) impairs PKC coupling to acetylcholine release potentiation. In addition, the inhibition of nPKCε translocation and therefore its activity impedes that presynaptic muscarinic autoreceptors and adenosine autoreceptors modulate transmitter secretion. Together, these results point to the importance of nPKCε isoform in the control of acetylcholine release in the neuromuscular junction.

Exogenous ciliary neurotrophic factor (CNTF) reduces synaptic depression during repetitive stimulation.

PubMed

Garcia, Neus; Santafé, Manel M; Tomàs, Marta; Priego, Mercedes; Obis, Teresa; Lanuza, Maria A; Besalduch, Nuria; Tomàs, Josep

2012-09-01

It has been shown that ciliary neurotrophic factor (CNTF) has trophic and maintenance effects on several types of peripheral and central neurons, glia, and cells outside the nervous system. Both CNTF and its receptor, CNTF-Rα, are expressed in the muscle. We use confocal immunocytochemistry to show that the trophic cytokine and its receptor are present in the pre- and post-synaptic sites of the neuromuscular junctions (NMJs). Applied CNTF (7.5-200 ng/ml, 60 min-3 h) does not acutely affect spontaneous potentials (size or frequency) or quantal content of the evoked acetylcholine release from post-natal (in weak or strong axonal inputs on dually innervated end plates or in the most mature singly innervated synapses at P6) or adult (P30) NMJ of Levator auris longus muscle of the mice. However, CNTF reduces roughly 50% the depression produced by repetitive stimulation (40 Hz, 2 min) on the adult NMJs. Our findings indicate that, unlike neurotrophins, exogenous CNTF does not acutely modulate transmitter release locally at the mammalian neuromuscular synapse but can protect mature end plates from activity-induced synaptic depression. © 2012 Peripheral Nerve Society.

Multi-beam transmitter geometries for free-space optical communications

NASA Astrophysics Data System (ADS)

Tellez, Jason A.; Schmidt, Jason D.

2010-02-01

Free-space optical communications systems provide the opportunity to take advantage of higher data transfer rates and lower probability of intercept compared to radio-frequency communications. However, propagation through atmospheric turbulence, such as for airborne laser communication over long paths, results in intensity variations at the receiver and a corresponding degradation in bit error rate (BER) performance. Previous literature has shown that two transmitters, when separated sufficiently, can effectively average out the intensity varying effects of the atmospheric turbulence at the receiver. This research explores the impacts of adding more transmitters and the marginal reduction in the probability of signal fades while minimizing the overall transmitter footprint, an important design factor when considering an airborne communications system. Analytical results for the cumulative distribution function are obtained for tilt-only results, while wave-optics simulations are used to simulate the effects of scintillation. These models show that the probability of signal fade is reduced as the number of transmitters is increased.

Radio controlled release apparatus for animal data acquisition devices

DOEpatents

Stamps, James Frederick

2000-01-01

A novel apparatus for reliably and selectively releasing a data acquisition package from an animal for recovery. The data package comprises two parts: 1) an animal data acquisition device and 2) a co-located release apparatus. One embodiment, which is useful for land animals, the release apparatus includes two major components: 1) an electronics package, comprising a receiver; a decoder comparator, having at plurality of individually selectable codes; and an actuator circuit and 2) a release device, which can be a mechanical device, which acts to release the data package from the animal. To release a data package from a particular animal, a radio transmitter sends a coded signal which is decoded to determine if the code is valid for that animal data package. Having received a valid code, the release device is activated to release the data package from the animal for subsequent recovery. A second embodiment includes floatation means and is useful for releasing animal data acquisition devices attached to sea animals. This embodiment further provides for releasing a data package underwater by employing an acoustic signal.

31 CFR 537.323 - U.S. registered money transmitter.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false U.S. registered money transmitter. 537.323 Section 537.323 Money and Finance: Treasury Regulations Relating to Money and Finance... General Definitions § 537.323 U.S. registered money transmitter. The term U.S. registered money...

31 CFR 538.319 - U.S. registered money transmitter.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false U.S. registered money transmitter. 538.319 Section 538.319 Money and Finance: Treasury Regulations Relating to Money and Finance... General Definitions § 538.319 U.S. registered money transmitter. The term U.S. registered money...

Compact self-contained electrical-to-optical converter/transmitter

DOEpatents

Seligmann, Daniel A.; Moss, William C.; Valk, Theodore C.; Conder, Alan D.

1995-01-01

A first optical receiver and a second optical receiver are provided for receiving a calibrate command and a power switching signal, respectively, from a remote processor. A third receiver is provided for receiving an analog electrical signal from a transducer. A calibrator generates a reference signal in response to the calibrate command. A combiner mixes the electrical signal with the reference signal to form a calibrated signal. A converter converts the calibrated signal to an optical signal. A transmitter transmits the optical signal to the remote processor. A primary battery supplies power to the calibrator, the combiner, the converter, and the transmitter. An optically-activated switch supplies power to the calibrator, the combiner, the converter, and the transmitter in response to the power switching signal. An auxiliary battery supplies power continuously to the switch.

Effects of radio transmitters on the behavior of Red-headed Woodpeckers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vukovich, Mark; Kilgo, John, C.

2009-05-01

ABSTRACT. Previous studies have revealed that radio-transmitters may affect bird behaviors, including feeding rates, foraging behavior, vigilance, and preening behavior. In addition, depending on the method of attachment, transmitters can potentially affect the ability of cavity-nesting birds to use cavities. Our objective was to evaluate effects of transmitters on the behavior of and use of cavities byRed-headedWoodpeckers (Melanerpes erythrocephalus). Using backpack harnesses, we attached 2.1-g transmitter packages that averaged 3.1% of body weight (range = 2.5–3.6%) to Red-headed Woodpeckers. We observed both radio-tagged (N = 23) and nonradio-tagged (N = 28) woodpeckers and determined the percentage of time spent engagedmore » in each of five behaviors: flight, foraging, perching, preening, and territorial behavior. We found no difference between the two groups in the percentage of time engaged in each behavior. In addition, we found that transmitters had no apparent effect on use of cavities for roosting by radio-tagged woodpeckers (N = 25).We conclude that backpack transmitters weighing less than 3.6% of body weight had no impact on either their behavior or their ability to use cavities.« less

Effects of radio transmitters on the behavior of Red-headed Woodpeckers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vukovich, Mark; Kilgo, John, C.

ABSTRACT. Previous studies have revealed that radio-transmitters may affect bird behaviors, including feeding rates, foraging behavior, vigilance, and preening behavior. In addition, depending on the method of attachment, transmitters can potentially affect the ability of cavity-nesting birds to use cavities. Our objective was to evaluate effects of transmitters on the behavior of and use of cavities byRed-headedWoodpeckers (Melanerpes erythrocephalus). Using backpack harnesses, we attached 2.1-g transmitter packages that averaged 3.1% of body weight (range = 2.5–3.6%) to Red-headed Woodpeckers. We observed both radio-tagged (N = 23) and nonradio-tagged (N = 28) woodpeckers and determined the percentage of time spent engagedmore » in each of five behaviors: flight, foraging, perching, preening, and territorial behavior. We found no difference between the two groups in the percentage of time engaged in each behavior. In addition, we found that transmitters had no apparent effect on use of cavities for roosting by radio-tagged woodpeckers (N = 25).We conclude that backpack transmitters weighing less than 3.6% of body weight had no impact on either their behavior or their ability to use cavities.« less

47 CFR 73.4108 - FM transmitter site map submissions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false FM transmitter site map submissions. 73.4108... RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4108 FM transmitter site map submissions. See Memorandum Opinion and Order and Public Notice, adopted October 24, 1986. 1 FCC Rcd 381 (1986...

Flat-topped beam transmittance in anisotropic non-Kolmogorov turbulent marine atmosphere

NASA Astrophysics Data System (ADS)

Ata, Yalçın; Baykal, Yahya

2017-10-01

Turbulence affects optical propagation, and, as a result, the intensity is attenuated along the path of propagation. The attenuation becomes significant when the turbulence becomes stronger. Transmittance is a measure indicating how much power is collected at the receiver after the optical wave propagates in the turbulent medium. The on-axis transmittance is formulated when a flat-topped optical beam propagates in a marine atmosphere experiencing anisotropic non-Kolmogorov turbulence. Variations in the transmittance are evaluated versus the beam source size, beam number, link distance, power law exponent, anisotropy factor, and structure constant. It is found that larger beam source sizes and beam numbers yield higher transmittance values; however, as the link distance, power law exponent, anisotropy factor, or structure constant increase, transmittance values are lowered. Our results will help in the performance evaluations of optical wireless communication and optical imaging systems operating in a marine atmosphere.

Postsynaptic Depolarization Enhances GABA Drive to Dorsomedial Hypothalamic Neurons through Somatodendritic Cholecystokinin Release.

PubMed

Crosby, Karen M; Baimoukhametova, Dinara V; Bains, Jaideep S; Pittman, Quentin J

2015-09-23

Somatodendritically released peptides alter synaptic function through a variety of mechanisms, including autocrine actions that liberate retrograde transmitters. Cholecystokinin (CCK) is a neuropeptide expressed in neurons in the dorsomedial hypothalamic nucleus (DMH), a region implicated in satiety and stress. There are clear demonstrations that exogenous CCK modulates food intake and neuropeptide expression in the DMH, but there is no information on how endogenous CCK alters synaptic properties. Here, we provide the first report of somatodendritic release of CCK in the brain in male Sprague Dawley rats. CCK is released from DMH neurons in response to repeated postsynaptic depolarizations, and acts in an autocrine fashion on CCK2 receptors to enhance postsynaptic NMDA receptor function and liberate the retrograde transmitter, nitric oxide (NO). NO subsequently acts presynaptically to enhance GABA release through a soluble guanylate cyclase-mediated pathway. These data provide the first demonstration of synaptic actions of somatodendritically released CCK in the hypothalamus and reveal a new form of retrograde plasticity, depolarization-induced potentiation of inhibition. Significance statement: Somatodendritic signaling using endocannabinoids or nitric oxide to alter the efficacy of afferent transmission is well established. Despite early convincing evidence for somatodendritic release of neurohypophysial peptides in the hypothalamus, there is only limited evidence for this mode of release for other peptides. Here, we provide the first evidence for somatodendritic release of the satiety peptide cholecystokinin (CCK) in the brain. We also reveal a new form of synaptic plasticity in which postsynaptic depolarization results in enhancement of inhibition through the somatodendritic release of CCK. Copyright © 2015 the authors 0270-6474/15/3513160-11$15.00/0.

Pathologic and physiologic effects associated with long-term intracoelomic transmitters in captive Siberian sturgeon

USGS Publications Warehouse

Boone, S. Shaun; Divers, Stephen J.; Camus, Alvin C.; Peterson, Douglas C.; Jennings, Cecil A.; Shelton, James L.; Hernandez, Sonia M.

2015-01-01

Intracoelomic transmitters are commonly used to evaluate migratory patterns, distribution, and habitat use of many species of fish. Currently, transmitter implantation relies mostly on the assumption that transmitters do not cause any adverse physiological or pathological effects on the animal. To investigate these effects, we surgically implanted 60 Siberian Sturgeon Acipenser baeri with transmitters that weighed less than 2% of their body weight. Postoperative assessments were conducted at 1, 2, 8, 12, 26, and 55 weeks to evaluate surgical healing and transmitter retention. Blood samples were collected before and after the 55-week study for serum cortisol analysis. Overall transmitter loss was 32%. Minor to moderate adhesions were noted at necropsy but did not appear to affect organ function. One fish was noted to have an intraintestinal transmitter at necropsy, but the fish was in overall good health. Long-term transmitter presence does not appear to increase serum cortisol levels or affect overall growth more than nontransmitter fish. Although long-term telemetry studies can be undertaken with minimal concern for negative physiological or pathological effects from transmitters, researchers should be aware that transmitter loss rates may be higher than previously thought. Mechanisms for transmitter loss may include expulsion through the surgical incision, expulsion through the mucocutaneous junction between the large intestine and the vent, or intraintestinal capture and expulsion through the vent. Received February 10, 2013; accepted June 10, 2013

Testing tail-mounted transmitters with Myocastor coypus (nutria)

USGS Publications Warehouse

Merino, S.; Carter, J.; Thibodeaux, G.

2007-01-01

We developed a tail-mounted radio-transmitter for Myocastor coypus (nutria) that offers a practical and efficient alternative to collar or implant methods. The mean retention time was 96 d (range 57-147 d, n = 7), making this a practical method for short-term studies. The tail-mounts were less injurious to animals than collars and easier for field researchers to implement than either collars or surgically implanted transmitters.

An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Huidong; Tian, Chuan; Lu, Jun

This paper presents a self-powered underwater acoustic transmitter using a piezoelectric beam to harvest the mechanical energy from fish swimming. This transmitter does not require a battery and is demonstrated in live fish. It transmits an acoustic waveform as the implanted fish swims. It enables long-term monitoring of aquatic animals.

Toward maximum transmittance into absorption layers in solar cells: investigation of lossy-film-induced mismatches between reflectance and transmittance extrema.

PubMed

Chang, Yin-Jung; Lai, Chi-Sheng

2013-09-01

The mismatch in film thickness and incident angle between reflectance and transmittance extrema due to the presence of lossy film(s) is investigated toward the maximum transmittance design in the active region of solar cells. Using a planar air/lossy film/silicon double-interface geometry illustrates important and quite opposite mismatch behaviors associated with TE and TM waves. In a typical thin-film CIGS solar cell, mismatches contributed by TM waves in general dominate. The angular mismatch is at least 10° in about 37%-53% of the spectrum, depending on the thickness combination of all lossy interlayers. The largest thickness mismatch of a specific interlayer generally increases with the thickness of the layer itself. Antireflection coating designs for solar cells should therefore be optimized in terms of the maximum transmittance into the active region, even if the corresponding reflectance is not at its minimum.

47 CFR 90.471 - Points of operation in internal transmitter control systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Points of operation in internal transmitter control systems. 90.471 Section 90.471 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control Systems § 90.471 Points of...

47 CFR 90.471 - Points of operation in internal transmitter control systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Points of operation in internal transmitter control systems. 90.471 Section 90.471 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control Systems § 90.471 Points of...

47 CFR 90.471 - Points of operation in internal transmitter control systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Points of operation in internal transmitter control systems. 90.471 Section 90.471 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control Systems § 90.471 Points of...

47 CFR 90.471 - Points of operation in internal transmitter control systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Points of operation in internal transmitter control systems. 90.471 Section 90.471 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control Systems § 90.471 Points of...

47 CFR 90.471 - Points of operation in internal transmitter control systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Points of operation in internal transmitter control systems. 90.471 Section 90.471 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control Systems § 90.471 Points of...

A 20-GHz IMPATT transmitter

NASA Technical Reports Server (NTRS)

Chan, J. L.; Sun, C.

1983-01-01

The engineering development of a solid state transmitter amplifier operating in the 20 GHz frequency band. The development effort involved a variety of disciplines including IMPATT device development, circulator design, simple and multiple diode circuits designs, and amplifier integration and test.

Fiber-Based, Trace-Gas, Laser Transmitter Technology Development for Space

NASA Technical Reports Server (NTRS)

Stephen, Mark; Yu, Anthony; Chen, Jeffrey; Nicholson, Jeffrey; Engin, Doruk; Mathason, Brian; Wu, Stewart; Allan, Graham; Hasselbrack, William; Gonzalez, Brayler;

Fiber-based, trace-gas, laser transmitter technology development for space

NASA Astrophysics Data System (ADS)

Stephen, Mark; Yu, Anthony; Chen, Jeffrey; Nicholson, Jeffrey; Engin, Doruk; Mathason, Brian; Wu, Stewart; Allan, Graham; Hasselbrack, William; Gonzales, Brayler; Han, Lawrence; Numata, Kenji; Storm, Mark; Abshire, James

2015-09-01

NASA's Goddard Space Flight Center (GSFC) is working on maturing the technology readiness of a laser transmitter designed for use in atmospheric CO2 remote-sensing. GSFC has been developing an airplane-based CO2 lidar instrument over several years to demonstrate the efficacy of the instrumentation and measurement technique and to link the science models to the instrument performance. The ultimate goal is to make space-based satellite measurements with global coverage. In order to accomplish this, we must demonstrate the technology readiness and performance of the components as well as demonstrate the required power-scaling to make the link with the required signal-to-noise-ratio (SNR). To date, all the instrument components have been shown to have the required performance with the exception of the laser transmitter. In this program we are working on a fiber-based master oscillator power amplifier (MOPA) laser transmitter architecture where we will develop a ruggedized package and perform the relevant environmental tests to demonstrate TRL-6. In this paper we will review our transmitter architecture and progress on the performance and packaging of the laser transmitter.

Acoustic Transmitters for Underwater Neutrino Telescopes

PubMed Central

Ardid, Miguel; Martínez-Mora, Juan A.; Bou-Cabo, Manuel; Larosa, Giuseppina; Adrián-Martínez, Silvia; Llorens, Carlos D.

2012-01-01

In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea currents. To guarantee a reliable and versatile system, the transceiver has the requirements of reduced cost, low power consumption, high pressure withstanding (up to 500 bars), high intensity for emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring and processing received signals. Secondly, a compact acoustic transmitter array has been developed for the calibration of acoustic neutrino detection systems. The array is able to mimic the signature of ultra-high-energy neutrino interaction in emission directivity and signal shape. The technique of parametric acoustic sources has been used to achieve the proposed aim. The developed compact array has practical features such as easy manageability and operation. The prototype designs and the results of different tests are described. The techniques applied for these two acoustic systems are so powerful and versatile that may be of interest in other marine applications using acoustic transmitters. PMID:22666022

Compact self-contained electrical-to-optical converter/transmitter

DOEpatents

Seligmann, D.A.; Moss, W.C.; Valk, T.C.; Conder, A.D.

1995-11-21

A first optical receiver and a second optical receiver are provided for receiving a calibrate command and a power switching signal, respectively, from a remote processor. A third receiver is provided for receiving an analog electrical signal from a transducer. A calibrator generates a reference signal in response to the calibrate command. A combiner mixes the electrical signal with the reference signal to form a calibrated signal. A converter converts the calibrated signal to an optical signal. A transmitter transmits the optical signal to the remote processor. A primary battery supplies power to the calibrator, the combiner, the converter, and the transmitter. An optically-activated switch supplies power to the calibrator, the combiner, the converter, and the transmitter in response to the power switching signal. An auxiliary battery supplies power continuously to the switch. 13 figs.

Remote control radioactive-waste removal system uses modulated laser transmitter

NASA Technical Reports Server (NTRS)

Burcher, E. E.; Kopia, L. P.; Rowland, C. W.; Sinclair, A. R.

1971-01-01

Laser remote control system consists of transmitter, auto tracker, and receiver. Transmitter and tracker, packaged together and bore sighted, constitute control station, receiver is slave station. Model has five command channels and optical link operating range of 110 m.

Subcutaneous implantation of satellite transmitters with percutaneous antennae into male polar bears (Ursus maritimus)

USGS Publications Warehouse

Mulcahy, Daniel M.; Garner, Gerald W.

1999-01-01

Male polar bears (Ursus maritimus) have not been successfully instrumented with satellite transmitters because they readily shed collar-mounted transmitters. Seven male polar bears were captured on the pack ice off the northern coast of Alaska and surgically implanted with satellite transmitters with percutaneous antennae into the subcutaneous space of the dorsal cervical region. Transmitters failed prematurely with lifetimes of 30-161 days (x̄ = 97 days). Efforts to relocate implanted bears after transmitters failed were not successful. The mean number of location solutions per transmitter was 204 (range 118-369). An average of 10% and 19% of the locations were accurate to <150 m and to 150-350 m, respectively. Our successful tracking of male polar bears, the high quality of locations obtained from transmitters with percutaneous antennae implanted in the subcutaneous space, and the low visibility of such units make further technical development worthwhile if the reason for premature failure of the transmitters can be determined.

Orbital-angular-momentum-multiplexed free-space optical communication link using transmitter lenses.

PubMed

Li, Long; Xie, Guodong; Ren, Yongxiong; Ahmed, Nisar; Huang, Hao; Zhao, Zhe; Liao, Peicheng; Lavery, Martin P J; Yan, Yan; Bao, ChangJing; Wang, Zhe; Willner, Asher J; Ashrafi, Nima; Ashrafi, Solyman; Tur, Moshe; Willner, Alan E

2016-03-10

In this paper, we explore the potential benefits and limitations of using transmitter lenses in an orbital-angular-momentum (OAM)-multiplexed free-space optical (FSO) communication link. Both simulation and experimental results indicate that within certain transmission distances, using lenses at the transmitter to focus OAM beams could reduce power loss in OAM-based FSO links and that this improvement might be more significant for higher-order OAM beams. Moreover, the use of transmitter lenses could enhance system tolerance to angular error between transmitter and receiver, but they might degrade tolerance to lateral displacement.

Influence of the Helicopter Time Domain Electromagnetic System Off-Time Response by the Transmitter Assembly

NASA Astrophysics Data System (ADS)

Vetrov, A.; Mejzr, I.

2010-12-01

While developing a new Helicopter Time Domain Electromagnetic system (P-THEM), Pico Envirotec Inc (PEI) has studied the effect of the transmitter assembly on the acquired data. The P-THEM system consists of a loop-transmitter assembly, powered by a motor generator, 3-axis coil receiver attached at the midpoint of a tow cable and an additional Z-axis (dB/dt) receiver installed on the rear section of the transmitter loop. The system is towed by a helicopter on a 230 foot long tow cable. The transmitter loop is designed to produce a peak magnetic moment of approximately 250,000 NIA with a base frequency of 30 Hz (adjustable to 25Hz) and a quarter length duty cycle (4 ms on-time). The secondary field acquired with a dB/dt receiver coil consists of a ground response and a system response: SF=Rg+Rsys, where SF - the secondary field, Rg - ground response, Rsys - system response. The system itself, especially the transmitter assembly, being a conductor in an induced magnetic field, creates a magnetic anomaly. The influence of the transmitter assembly anomaly on the received signal depends on the position of the receiver coil against the transmitter, the intensity of on-time pulse and transmitter electro-magnetic properties. At the same time, the ground response acquired with a receiver coil depends on the length and the moment of transmitter pulse, as well as the position and distance of the receiver coil from the ground. This can be for vertical field (Z) receiver coil described as RXz(t)=e(t)pz(t)Rgz(t)+d(t)k(t)j(t)TXz(t), where RXz(t) - receiver response, e(t) - elevation of the receiver over the ground, pz(t) - horizontal projection of the receiver coil, Rgz(t) - vertical component of ground response, d(t) - distance (elevation) between the receiver coil and the transmitter loop, k(t) - the position of the receiver in the transmitter field, j(t) - the transmitter assembly electromagnetic properties, TXz(t) -transmitter field (Primary field on-time, and transmitter

Upregulation of transmitter release probability improves a conversion of synaptic analogue signals into neuronal digital spikes

PubMed Central

2012-01-01

Action potentials at the neurons and graded signals at the synapses are primary codes in the brain. In terms of their functional interaction, the studies were focused on the influence of presynaptic spike patterns on synaptic activities. How the synapse dynamics quantitatively regulates the encoding of postsynaptic digital spikes remains unclear. We investigated this question at unitary glutamatergic synapses on cortical GABAergic neurons, especially the quantitative influences of release probability on synapse dynamics and neuronal encoding. Glutamate release probability and synaptic strength are proportionally upregulated by presynaptic sequential spikes. The upregulation of release probability and the efficiency of probability-driven synaptic facilitation are strengthened by elevating presynaptic spike frequency and Ca2+. The upregulation of release probability improves spike capacity and timing precision at postsynaptic neuron. These results suggest that the upregulation of presynaptic glutamate release facilitates a conversion of synaptic analogue signals into digital spikes in postsynaptic neurons, i.e., a functional compatibility between presynaptic and postsynaptic partners. PMID:22852823

Solid state Ku-band spacecraft transmitters

NASA Technical Reports Server (NTRS)

Wisseman, W. R.; Tserng, H. Q.; Coleman, D. J.; Doerbeck, F. H.

1977-01-01

A transmitter is considered that consists of GaAs IMPATT and Read diodes operating in a microstrip circuit environment to provide amplification with a minimum of 63 db small signal gain and a minimum compressed gain at 5 W output of 57 db. Reported are Schottky-Read diode design and fabrication, microstrip and circulator optimization, preamplifier development, power amplifier development, dc-to-dc converter design, and integration of the breadboard transmitter modules. A four-stage power amplifier in cascade with a three-stage preamplifier had an overall gain of 56.5 db at 13.5 GHz with a power output of 4.5 W. A single-stage Read amplifier delivered 5.9 W with 4 db gain at 22% efficiency.

Micro-miniature radio frequency transmitter for communication and tracking applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crutcher, R.I.; Emery, M.S.; Falter, K.G.

1996-12-31

A micro-miniature radio frequency (rf) transmitter has been developed and demonstrated by the Oak Ridge National Laboratory. The objective of the rf transmitter development was to maximize the transmission distance while drastically shrinking the overall transmitter size, including antenna. Based on analysis and testing, an application-specific integrated circuit (ASIC) with a 16-GHz gallium arsenide (GaAs) oscillator and integrated on-chip antenna was designed and fabricated using microwave monolithic integrated circuit (MMIC) technology. Details of the development and the results of various field tests will be discussed. The rf transmitter is applicable to covert surveillance and tracking scenarios due to its smallmore » size of 2.2 x 2.2 mm, including the antenna. Additionally, the 16-GHz frequency is well above the operational range of consumer-grade radio scanners, providing a degree of protection from unauthorized interception. Variations of the transmitter design have been demonstrated for tracking and tagging beacons, transmission of digital data, and transmission of real-time analog video from a surveillance camera. Preliminary laboratory measurements indicate adaptability to direct-sequence spread-spectrum transmission, providing a low probability of intercept and/or detection. Concepts related to law enforcement applications will be presented.« less

Measurement device for high-precision spectral transmittance of solar blind filter

NASA Astrophysics Data System (ADS)

Wang, Yan; Qian, Yunsheng; Lv, Yang; Feng, Cheng; Liu, Jian

2017-02-01

In order to measure spectral transmittance of solar-blind filter ranging from ultraviolet to visible light accurately, a high-precision filter transmittance measuring system based on the ultraviolet photomultiplier is developed. The calibration method is mainly used to measure transmittance in this system, which mainly consists of an ultraviolet photomultiplier as core of the system and a lock-in amplifier combined with an optical modulator as the aided measurement for the system. The ultraviolet photomultiplier can amplify the current signal through the filter and have the characteristics of low dark current and high luminance gain. The optical modulator and the lock-in amplifier can obtain the signal from the photomultiplier and inhibit dark noise and spurious signal effectively. Through these two parts, the low light passing through the filters can be detected and we can calculate the transmittance by the optical power detected. Based on the proposed system, the limit detection of the transmittance can reach 10-12, while the result of the conventional approach is merely 10-6. Therefore, the system can make an effective assessment of solar blind ultraviolet filters.

47 CFR 80.855 - Radiotelephone transmitter.

Code of Federal Regulations, 2013 CFR

2013-10-01

... series network of 10 ohms resistance and 200 picofarads capacitance, or an artificial antenna of 50 ohms... radiotelephone installation normally installed on board ship, may be required. (e) The transmitter must provide...

47 CFR 80.855 - Radiotelephone transmitter.

Code of Federal Regulations, 2012 CFR

2012-10-01

... series network of 10 ohms resistance and 200 picofarads capacitance, or an artificial antenna of 50 ohms... radiotelephone installation normally installed on board ship, may be required. (e) The transmitter must provide...

47 CFR 80.855 - Radiotelephone transmitter.

Code of Federal Regulations, 2014 CFR

2014-10-01

... series network of 10 ohms resistance and 200 picofarads capacitance, or an artificial antenna of 50 ohms... radiotelephone installation normally installed on board ship, may be required. (e) The transmitter must provide...

47 CFR 80.855 - Radiotelephone transmitter.

Code of Federal Regulations, 2011 CFR

2011-10-01

... series network of 10 ohms resistance and 200 picofarads capacitance, or an artificial antenna of 50 ohms... radiotelephone installation normally installed on board ship, may be required. (e) The transmitter must provide...

Citrate Modulates the Regulation by Zn2+ of N-Methyl-D-Aspartate Receptor-Mediated Channel Current and Neurotransmitter Release

NASA Astrophysics Data System (ADS)

Westergaard, Niels; Banke, Tue; Wahl, Philip; Sonnewald, Ursula; Schousboe, Arne

1995-04-01

The effect of the two metal-ion chelators EDTA and citrate on the action of N-methyl-D-aspartate (NMDA) receptors was investigated by use of cultured mouse cerebellar granule neurons and Xenopus oocytes, respectively, to monitor either NMDA-evoked transmitter release or membrane currents. Transmitter release from the glutamatergic neurons was determined by superfusion of the cells after preloading with the glutamate analogue D-[^3H]aspartate. The oocytes were injected with mRNA isolated from mouse cerebellum and, after incubation to allow translation to occur, currents mediated by NMDA were recorded electrophysiologically by voltage clamp at a holding potential of -80 mV. It was found that citrate as well as EDTA could attenuate the inhibitory action of Zn2+ on NMDA receptor-mediated transmitter release from the neurons and membrane currents in the oocytes. These effects were specifically related to the NMDA receptor, since the NMDA receptor antagonist MK-801 abolished the action and no effects of Zn2+ and its chelators were observed when kainate was used to selectively activate non-NMDA receptors. Since it was additionally demonstrated that citrate (and EDTA) preferentially chelated Zn2+ rather than Ca2+, the present findings strongly suggest that endogenous citrate released specifically from astrocytes into the extracellular space in the brain may function as a modulator of NMDA receptor activity. This is yet another example of astrocytic influence on neuronal activity.

Surgical insertions of transmitters and telemetry methods in fisheries research

USGS Publications Warehouse

Wargo Rub, A. Michelle; Jepsen, Niels; Liedtke, Theresa L.; Moser, L; Weber III, E. P. Scott

2015-01-01

Use of electronic transmitter and monitoring systems to track movements of aquatic animals has increased continuously since the inception of these systems in the mid-1950s. The purpose of the present report is to provide information about veterinary principles and their incorporation into surgical implantation procedures for fish. We also intend to provide insight into the unique challenges of field-based aquatic surgical studies. Within this context, 4 aspects of the process for surgical implantation of transmitters in fish (ie, handling, aseptic technique, anesthesia, and implantation) will be described. Effects of surgical insertion of transmitters (ie, tagging) and aspects of the surgical implantation process where collaboration and professional exchanges among nonveterinarian researchers and veterinarians may be most fruitful will be discussed. Although this report focuses on surgical implantation, the principles and protocols described here (other than incision and suture placement) are also applicable to studies that involve injection of transmitters into fish.

Airborne Measurements of Atmospheric Methane Using Pulsed Laser Transmitters

NASA Technical Reports Server (NTRS)

Numata, Kenji; Riris, Haris; Wu, Stewart; Gonzalez, Brayler; Rodriguez, Michael; Hasselbrack, William; Fahey, Molly; Yu, Anthony; Stephen, Mark; Mao, Jianping;

Implantable microencapsulated dopamine (DA): prolonged functional release of DA in denervated striatal tissue.

PubMed

McRae, A; Hjorth, S; Mason, D; Dillon, L; Tice, T

1990-01-01

Biodegradable controlled-release microcapsule systems made with the biocompatible biodegradable polyester excipient poly [DL-lactide-co-gly-colide] constitute an exciting new technology for drug delivery to the central nervous system (CNS). The present study describes functional observations indicating that implantation of dopamine (DA) microcapsules encapsulated within two different polymer excipients into denervated striatal tissue assures a prolonged release of the transmitter in vivo. This technology has a considerable potential for basic and possibly clinical research.

47 CFR 80.909 - Radiotelephone transmitter.

Code of Federal Regulations, 2010 CFR

2010-10-01

... requirements of § 80.923 of this part; and (2) The transmitter, with normal operating voltages applied, has... effective resistance and 200 picofarads capacitance or an artificial antenna of 50 ohms nominal impedance...

47 CFR 80.855 - Radiotelephone transmitter.

Code of Federal Regulations, 2010 CFR

2010-10-01

... series network of 10 ohms resistance and 200 picofarads capacitance, or an artificial antenna of 50 ohms... protected from excessive currents and voltages. (g) A durable nameplate must be mounted on the transmitter...

Estimating incision healing rate for surgically implanted acoustic transmitters from recaptured fish

USGS Publications Warehouse

Schoonyan, Abby; Kraus, Richard T.; Faust, Matthew D.; Vandergoot, Christopher; Cooke, Steven J.; Cook, H. Andrew; Hayden, Todd A.; Krueger, Charles C.

2017-01-01

Background Intracoelomic implantation of electronic tags has become a common method in fishery research, but rarely are fish examined by scientists after release to understand the extent that surgical incisions have healed. Walleye (Sander vitreus) are a valuable, highly exploited fishery resource in the Laurentian Great Lakes. Here, fishery capture of walleye with internal acoustic transmitters combined with a high reward program provided multiple opportunities to examine photographs and quantify the status of surgical incisions. Walleye (n = 926) from reef and river spawning populations in Lake Erie and Lake Huron were implanted with acoustic transmitters during spring spawning events from 2011 to 2016. Incisions were closed with polydioxanone monofilament using two to three interrupted sutures. Out of 276 recaptured fish, 60 incision sites were clearly visible in photographs, and these were scored by two independent readers for incision closure, inflammation, and the presence of sutures.Results While incision sites were completely closed by 61 days post-release (95% CI 44–94), sutures remained for up to 866 days. Sutures were expelled serially during a protracted period, and the probability of observing at least one suture in a recaptured fish declined below 50% after 673 days (95% CI 442–1016). Inflammation at the incision increased during the first 71 days and then declined monotonically, remaining detectable at low levels.Conclusion Our results emphasized that sutures remained in free-ranging fish past the time when they were beneficial for incision healing. Most dissolvable sutures have been designed for use in endotherms where the body temperature and internal milieu differ dramatically from the conditions experienced by fishes in temperate climates. Identification of new suture materials for fish that facilitate healing while absorbing or dissolving in a reasonable period (e.g., a few weeks to three months) in colder temperatures (e.g., <12 °C) would

Role of different types of Ca2+ channels and a reticulum-like Ca2+ pump in neurotransmitter release.

PubMed

Fossier, P; Baux, G; Tauc, L

1993-01-01

The factors controlling the Ca2+ concentration directly responsible for triggering acetylcholine (ACh) release were investigated at an identified neuro-neuronal synapse of the Aplysia buccal ganglion. The types of presynaptic voltage-gated Ca2+ channels associated with transmitter release were determined by using selective blockers such as nifedipine, omega-conotoxin and a partially purified extract from the venom of a funnel web spider (FTx). L-type, N-type and P-type Ca2+ channels are present in the presynaptic neuron. The influx of Ca2+ through both N- and P-types induces the release of ACh whereas Ca2+ flowing through L-type channels modulates the duration of the presynaptic action potential by controlling the Ca(2+)-dependent K+ current. tBuBHQ, a blocker of the reticulum Ca2+ pump, induces a potentiation of evoked release without modifying the presynaptic Ca2+ influx. This seems to indicate that a part of the Ca2+ entering the presynaptic terminal through N- and P-type Ca2+ channels is sequestered in a presynaptic reticulum-like Ca2+ buffer preventing these ions from contributing to ACh release. To exert its control, this Ca2+ buffer must be located close to both the presynaptic Ca2+ channels and the transmitter release mechanism.

Do transmitters affect survival and body condition of American beavers Castor canadensis?

USGS Publications Warehouse

Smith, Joshua B.; Windels, Steve K.; Wolf, Tiffany; Klaver, Robert W.; Belant, Jerrold L.

2016-01-01

One key assumption often inferred with using radio-equipped individuals is that the transmitter has no effect on the metric of interest. To evaluate this assumption, we used a known fate model to assess the effect of transmitter type (i.e. tail-mounted or peritoneal implant) on short-term (one year) survival and a joint live—dead recovery model and results from a mark—recapture study to compare long-term (eight years) survival and body condition of ear-tagged only American beavers Castor canadensis to those equipped with radio transmitters in Voyageurs National Park, Minnesota, USA. Short-term (1-year) survival was not influenced by transmitter type (wi = 0.64). Over the 8-year study period, annual survival was similar between transmitter-equipped beavers (tail-mounted and implant transmitters combined; 0.76; 95% CI = 0.45–0.91) versus ear-tagged only (0.78; 95% CI = 0.45–0.93). Additionally, we found no difference in weight gain (t9 = 0.25, p = 0.80) or tail area (t11 = 1.25, p = 0.24) from spring to summer between the two groups. In contrast, winter weight loss (t22 = - 2.03, p = 0.05) and tail area decrease (t30 = - 3.04, p = 0.01) was greater for transmitterequipped (weight = - 3.09 kg, SE = 0.55; tail area = - 33.71 cm2, SE = 4.80) than ear-tagged only (weight = - 1.80 kg, SE = 0.33; tail area = - 12.38 cm2, SE = 5.13) beavers. Our results generally support the continued use of transmitters on beavers for estimating demographic parameters, although we recommend additional assessments of transmitter effects under different environmental conditions.

Comparison of different measurement methods for transmittance haze

NASA Astrophysics Data System (ADS)

Yu, Hsueh-Ling; Hsaio, Chin-Chai

2009-08-01

Transmittance haze is increasingly important to the LCD and solar cell industry. Most commercial haze measurement instruments are designed according to the method recommended in the documentary standards like ASTM D 1003 (ASTM 2003 Standard Test Method for Haze and Luminous Transmittance of Transparent Plastics), JIS K 7361 (JIS 1997 Plastics—Determination of the Total Luminous Transmittance of Transparent Materials—Part 1: Single Beam Instrument) and ISO 14782 (ISO 1997 Plastics—Determination of Haze of Transparent Materials). To improve the measurement accuracy of the current standards, a new apparatus was designed by the Center for Measurement Standards (Yu et al 2006 Meas. Sci. Technol. 17 N29-36). Besides the methods mentioned above, a double-beam method is used in the design of some instruments. There are discrepancies between the various methods. But no matter which method is used, a white standard is always needed. This paper compares the measurement results from different methods, presents the effect of the white standard, and analyses the measurement uncertainty.

Examination of an optical transmittance test for photovoltaic encapsulation materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, David C.; Bengoechea, Jaione; Bokria, Jayesh G.

2013-09-24

The optical transmittance of encapsulation materials is a key characteristic for their use in photovoltaic (PV) modules. Changes in transmittance with time in the field affect module performance, which may impact product warranties. Transmittance is important in product development, module manufacturing, and field power production (both immediate and long-term). Therefore, an international standard (IEC 62788-1-4) has recently been proposed by the Encapsulation Task-Group within the Working Group 2 (WG2) of the International Electrotechnical Commission (IEC) Technical Committee 82 (TC82) for the quantification of the optical performance of PV encapsulation materials. Existing standards, such as ASTM E903, are general and moremore » appropriately applied to concentrated solar power than to PV. Starting from the optical transmittance measurement, the solar-weighted transmittance of photon irradiance, yellowness index (which may be used in aging studies to assess durability), and ultraviolet (UV) cut-off wavelength may all be determined using the proposed standard. The details of the proposed test are described. The results of a round-robin experiment (for five materials) conducted at seven laboratories to validate the test procedure using representative materials are also presented. For example, the Encapsulation Group actively explored the measurement requirements (wavelength range and resolution), the requirements for the spectrophotometer (including the integrating sphere and instrument accessories, such as a depolarizer), specimen requirements (choice of glass-superstrate and -substrate), and data analysis (relative to the light that may be used in the PV application). The round-robin experiment identified both intra- and inter-laboratory instrument precision and bias for five encapsulation materials (encompassing a range of transmittance and haze-formation characteristics).« less

In-Flight Performance of the Mercury Laser Altimeter Laser Transmitter

NASA Technical Reports Server (NTRS)

Yu, Anthony W.; Sun, Xiaoli; Li, Steven X.; Cavanaugh, John F.; Neumann, Gregory A.

2014-01-01

The Mercury Laser Altimeter (MLA) is one of the payload instruments on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, which was launched on August 3, 2004. MLA maps Mercury's shape and topographic landforms and other surface characteristics using a diode-pumped solid-state laser transmitter and a silicon avalanche photodiode receiver that measures the round-trip time of individual laser pulses. The laser transmitter has been operating nominally during planetary flyby measurements and in orbit about Mercury since March 2011. In this paper, we review the MLA laser transmitter telemetry data and evaluate the performance of solid-state lasers under extended operation in a space environment.

30. View of mezzanine floor level in transmitter building no. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. View of mezzanine floor level in transmitter building no. 102 showing control transmitter electronic cabinets and control modules. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Vesicular glutamate transporter VGLUT2 expression levels control quantal size and neuropathic pain.

PubMed

Moechars, Diederik; Weston, Matthew C; Leo, Sandra; Callaerts-Vegh, Zsuzsanna; Goris, Ilse; Daneels, Guy; Buist, A; Cik, M; van der Spek, P; Kass, Stefan; Meert, Theo; D'Hooge, Rudi; Rosenmund, Christian; Hampson, R Mark

2006-11-15

Uptake of L-glutamate into synaptic vesicles is mediated by vesicular glutamate transporters (VGLUTs). Three transporters (VGLUT1-VGLUT3) are expressed in the mammalian CNS, with partial overlapping expression patterns, and VGLUT2 is the most abundantly expressed paralog in the thalamus, midbrain, and brainstem. Previous studies have shown that VGLUT1 is necessary for glutamatergic transmission in the hippocampus, but the role of VGLUT2 in excitatory transmission is unexplored in glutamatergic neurons and in vivo. We examined the electrophysiological and behavioral consequences of loss of either one or both alleles of VGLUT2. We show that targeted deletion of VGLUT2 in mice causes perinatal lethality and a 95% reduction in evoked glutamatergic responses in thalamic neurons, although hippocampal synapses function normally. Behavioral analysis of heterozygous VGLUT2 mice showed unchanged motor function, learning and memory, acute nociception, and inflammatory pain, but acquisition of neuropathic pain, maintenance of conditioned taste aversion, and defensive marble burying were all impaired. Reduction or loss of VGLUT2 in heterozygous and homozygous VGLUT2 knock-outs led to a graded reduction in the amplitude of the postsynaptic response to single-vesicle fusion in thalamic neurons, indicating that the vesicular VGLUT content is critically important for quantal size and demonstrating that VGLUT2-mediated reduction of excitatory drive affects specific forms of sensory processing.

Accurate method for luminous transmittance and signal detection quotients measurements in sunglasses lenses

NASA Astrophysics Data System (ADS)

Loureiro, A. D.; Gomes, L. M.; Ventura, L.

2018-02-01

The international standard ISO 12312-1 proposes transmittance tests that quantify how dark sunglasses lenses are and whether or not they are suitable for driving. To perform these tests a spectrometer is required. In this study, we present and analyze theoretically an accurate alternative method for performing these measurements using simple components. Using three LEDs and a four-channel sensor we generated weighting functions similar to the standard ones for luminous and traffic lights transmittances. From 89 sunglasses lens spectroscopy data, we calculated luminous transmittance and signal detection quotients using our obtained weighting functions and the standard ones. Mean-difference Tukey plots were used to compare the results. All tested sunglasses lenses were classified in the right category and correctly as suitable or not for driving. The greatest absolute errors for luminous transmittance and red, yellow, green and blue signal detection quotients were 0.15%, 0.17, 0.06, 0.04 and 0.18, respectively. This method will be used in a device capable to perform transmittance tests (visible, traffic lights and ultraviolet (UV)) according to the standard. It is important to measure rightly luminous transmittance and relative visual attenuation quotients to report correctly whether or not sunglasses are suitable for driving. Moreover, standard UV requirements depend on luminous transmittance.

In space performance of the lunar orbiter laser altimeter (LOLA) laser transmitter

NASA Astrophysics Data System (ADS)

Yu, Anthony W.; Shaw, George B.; Novo-Gradac, Ann Marie; Li, Steven X.; Cavanaugh, John

2011-11-01

In this paper we present the final configuration of the space flight laser transmitter as delivered to the Lunar Orbiter Laser Altimeter (LOLA) instrument along with some in-space operation performance data. The LOLA instrument is designed to map the lunar surface and provide unprecedented data products in anticipation of future manned flight missions. The laser transmitter has been operating on orbit at the Moon continuously since July 2009 and accumulated over 1.8 billion laser shots in space. The LOLA laser transmitter design has heritage dated back to the MOLA laser transmitter launched more than 10 years ago and incorporates lessons learned from previous laser altimeter missions at NASA Goddard Space Flight Center.

Transmittance measurements at DIRT-III, a preliminary report

NASA Astrophysics Data System (ADS)

Curcio, J. A.; Haught, K. M.

1981-03-01

This preliminary report describes the visible and infrared transmittances measured through dust clouds and rain at the Dusty Infrared Test-III (DIRT-III), Fort Polk, Louisiana, April - May 1980. The measurement system was the Naval Research Laboratory (NRL) transmissometer operating at 0.55, 1.06, and 10.37 micrometers. Data were collected through dust clouds produced by various types of munitions and high explosives in the natural soil and tailored soils consisting of sand, silt, clay, and various mixtures. The onset of a rainstorm also provided the opportunity to measure transmittances for varying precipitation rates.

Effects of implanted transmitters on adult bluegills at two temperatures

USGS Publications Warehouse

Knights, Brent C.; Lasee, Becky A.

1996-01-01

Laterally compressed panfishes are small and have limited intraperitoneal space; thus, they may suffer adversely from surgically implanted transmitters even if the transmitter meets the generally recommended ratio of transmitter weight to fish weight of 2%. We studied the effects of intraperitoneal transmitters (2.81 g) on survival, growth, healing, and health of bluegills Lepomis macrochirus (mean weight 133 g) held for 8 weeks at 6 degree C and 20 degree C. Radio-tagged bluegills at 20 degree C had a mortality rate of 10% and tag loss rate of 15%. At 6 degree C, bluegills had no mortality or tag loss. Radio-tagged and reference fish fed in both 20 degree C raceways; however, a few reference fish appeared dominant at feeding time. This dominance by a few reference fish was also indicated by a large weight gain for three reference fish in each 20 degree C raceway. At 6 degree C, neither reference fish nor radio-tagged fish fed activity. Radio-tagged fish held at 20 degree C exhibited pelvic fin erosion, erythema and necrosis at the antenna exit and at suture insertions, and lost or loose sutures, effects not observed in other test fishes. Examination of fish held at 20 degree C also showed enclosure of the transmitters in a fibrous capsule and adhesion of visceral organs. Epithelialization over the incision occurred in radio-tagged bluegills at both temperatures, but there was little further healing at 6 degree C. At 20 degree C, tissue responses included chronic inflammation and dermal granulation. Radio-tagged fish did not appear to be more susceptible than reference fish to bacterial infection. Mortality, adverse morphological effects, altered behavior, and limited healing in bluegills suggest that implanted transmitters impaired their health. Thus, movement and habitat use data collected by telemetry for this species and perhaps for other panfishes should be interpreted with caution.

Evaluation of vaginal implant transmitters in elk (Cervus elaphus nelsoni).

Treesearch

Bruce K. Johnson; Terrance McCoy; Christopher O. Kochanny; Rachel C. Cook

2006-01-01

The effects of vaginal implant transmitters for tissue damage after 11 wk in 13 captive adult elk (Cervus elaphus nelsoni) and subsequent reproductive performance in 38 free-ranging elk were evaluated. Vaginal implant transmitters are designed to be shed at parturition and are used to locate birth sites of wild ungulates; however, potential adverse...

Loss from harlequin ducks of abdominally implanted radio transmitters equipped with percutaneous antennas

USGS Publications Warehouse

Mulcahy, D.M.; Esler, Daniel N.; Stoskopf, M.K.

1999-01-01

We documented extrusion and loss of abdominally implanted radio transmitters with percutaneous antennas from adult female Harlequin Ducks (Histrionicus histrionicus). Birds were captured during wing molt (late August to mid-September) in 1995-1997. Of 44 Harlequin Ducks implanted with radios and recaptured, 7 (16%) had lost their transmitters and 5 (11%) had radios in the process of extruding. Most (11 of 12) extrusions and losses occurred in birds implanted with radios in 1996 and recaptured in 1997. We suggest that transmitter extrusions and losses were due largely to changes in transmitter design made between 1095 and 1996. Transmitters implanted in 1996 were cylindrical rather than spherical, had a flat end with an abrupt edge, and the lower portion of the antenna was reinforced. Radio losses occurred after the 7-mo monitoring period and caused no apparent harm to the birds. Investigators using implanted radios with percutaneous antennas for long-term projects should be aware of the potential for radio extrusion and should minimize the problem by using transmitters that have no sharp edges and that are wide, rather than narrow.

Prediction of transmittance spectra for transparent composite electrodes with ultra-thin metal layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Zhao; Alford, T. L., E-mail: TA@asu.edu; Khorasani, Arash Elhami

2015-11-28

Recent interest in indium-free transparent composite-electrodes (TCEs) has motivated theoretical and experimental efforts to better understand and enhance their electrical and optical properties. Various tools have been developed to calculate the optical transmittance of multilayer thin-film structures based on the transfer-matrix method. However, the factors that affect the accuracy of these calculations have not been investigated very much. In this study, two sets of TCEs, TiO{sub 2}/Au/TiO{sub 2} and TiO{sub 2}/Ag/TiO{sub 2}, were fabricated to study the factors that affect the accuracy of transmittance predictions. We found that the predicted transmittance can deviate significantly from measured transmittance for TCEs thatmore » have ultra-thin plasmonic metal layers. The ultrathin metal layer in the TCE is typically discontinuous. When light interacts with the metallic islands in this discontinuous layer, localized surface plasmons are generated. This causes extra light absorption, which then leads to the actual transmittance being lower than the predicted transmittance.« less

Application of a modified harness design for attachment of radio transmitters to shorebirds

USGS Publications Warehouse

Sanzenbacher, Peter M.; Haig, Susan M.; Oring, Lewis W.

2000-01-01

Radio transmitter attachment methodology is important to the design of radio telemetry studies. In 1998, we attached 5 transmitters to a captive population of Western Sandpipers (Calidris mauri) and 7 transmitters to wild Killdeer (Charadriusv ociferus) using a modified version of the Rappole and Tipton (1991) figure-8 leg-loop harness. Captive birds fitted with harnesses did not exhibit quantifiable differences in behavior relative to control birds. Based on initial success in using the leg-loop harnesses, we used harnesses to attach transmitters in the wild to 30 Killdeer and 49 Dunlin (Calidris alpina) during the winters of 1998-1999 and 1999-2000. This was part of a study on movements of wintering shorebirds in the Willamette Valley of Oregon, USA. Wild birds showed no adverse effects of the harnesses.Thus, the described harness is a practical method for attachment of transmitters to shorebirds. Advantages of this harness method include a reduction in handling time at capture, elimination of the need to clip feathers for attachment, and increased transmitter retention time.

A new topology and control method for electromagnetic transmitter power supplies

NASA Astrophysics Data System (ADS)

Zhang, Yiming; Zhang, Jialin; Yuan, Dakang

2017-04-01

As essential equipment for electromagnetic exploration, electromagnetic transmitter reverse the steady power supply with desired frequency and transmit the power through grounding electrodes. To obtain effective geophysical data during deep exploration, the transmitter needs to be high-voltage, high-current, with high-accuracy output, and yet compact and light. The researches on the power supply technologies for high-voltage high-power electromagnetic transmitter is of significant importance to the deep geophysical explorations. Therefore, the performance of electromagnetic transmitter is mainly subject to the following two aspects: the performance of emission current and voltage, and the power density. These requirements bring technical difficulties to the development of power supplies. Conventionally, high-frequency switching power supplies are applied in the design of a high-power transmitter power supply. However, the structure of the topology is complicate, which may reduce the controllability of the output voltage and the reliability of the system. Without power factor control, the power factor of the structure is relatively low. Moreover high switching frequency causes high loss. With the development of the PWM (pulse width modulation) technique, its merits of simple structure, low loss, convenient control and unit power factor have made it popular in electrical energy feedback, active filter, and power factor compensation. Studies have shown that using PWM converters and space vector modulation have become the trend in designing transmitter power supply. However, the earth load exhibits different impedances at different frequencies. Thus ensuing high-accuracy and a stable output from a transmitter power supply in harsh environment has become a key topic in the design of geophysical exploration instruments. Based on SVPWM technology, an electromagnetic transmitter power supply has been designed and its control strategy has been studied. The transmitting

Photonic integrated transmitter and receiver for NG-PON2

NASA Astrophysics Data System (ADS)

Tavares, Ana; Lopes, Ana; Rodrigues, Cláudio; Mãocheia, Paulo; Mendes, Tiago; Brandão, Simão.; Rodrigues, Francisco; Ferreira, Ricardo; Teixeira, António

2014-08-01

In this paper the authors present a monolithic Photonic Integrated Circuit which includes a transmitter and a receiver for NG-PON2. With this layout it is possible to build an OLT and, by redesigning some filters, also an ONU. This technology allows reducing the losses in the transmitter and in the receiver, increasing power budget, and also reducing the OEO conversions, which has been a major problem that operators want to surpass.

50 Mb/s, 220-mW Laser-Array Transmitter

NASA Technical Reports Server (NTRS)

Cornwell, Donald M., Jr.

1992-01-01

Laser transmitter based on injection locking produces single-wavelength, diffraction-limited, single-lobe beam. Output stage is array of laser diodes producing non-diffraction-limited, multi-mode beam in absence of injection locking. Suitable for both free-space and optical-fiber communication systems. Because beam from transmitter focused to spot as small as 5 micrometers, devices usable for reading and writing optical disks at increased information densities. Application also in remote sensing and ranging.

Exciter For X-Band Transmitter And Receiver

NASA Technical Reports Server (NTRS)

Johns, Carl E.

1989-01-01

Report describes developmental X-band exciter for X-band uplink subsystem of Deep Space Network. X-band transmitter-exciting signal expected to have fractional frequency stability of 5.2 X 10 to negative 15th power during 1,000-second integration period. Generates coherent test signals for S- and X-band Block III translator of Deep Space Network, Doppler-reference signal for associated Doppler-extractor system, first-local-oscillator signal for associated receiver, and reference signal for associated ranging subsystem. Tests of prototype exciter show controlling and monitoring and internal phase-correcting loops perform according to applicable design criteria. Measurements of stability of frequency and of single-sideband noise spectral density of transmitter-exciting signal made subsequently.

Technique for implanting radio transmitters subcutaneously in day-old ducklings

USGS Publications Warehouse

Korschgen, C.E.; Kenow, K.P.; Green, W.L.; Samuel, M.D.; Sileo, L.

1996-01-01

We developed and evaluated a surgical procedure for implanting radio transmitters in 1-d-old Canvasback (Aythya valisineria) ducklings. Transmitters (1.5 g) were implanted subcutaneously on the back of ducklings while under a general anesthetic, isoflurane, within a few hours of hatching. Evaluations indicate that the procedure is a reliable method for radio-marking ducklings.

Temporal Stability of GPS Transmitter Group Delay Variations.

PubMed

Beer, Susanne; Wanninger, Lambert

2018-05-29

The code observable of global navigation satellite systems (GNSS) is influenced by group delay variations (GDV) of transmitter and receiver antennas. For the Global Positioning System (GPS), the variations can sum up to 1 m in the ionosphere-free linear combination and thus can significantly affect precise code applications. The contribution of the GPS transmitters can amount to 0.8 m peak-to-peak over the entire nadir angle range. To verify the assumption of their time-invariance, we determined daily individual satellite GDV for GPS transmitter antennas over a period of more than two years. Dual-frequency observations of globally distributed reference stations and their multipath combination form the basis for our analysis. The resulting GPS GDV are stable on the level of a few centimeters for C1, P2, and for the ionosphere-free linear combination. Our study reveals that the inconsistencies of the GDV of space vehicle number (SVN) 55 with respect to earlier studies are not caused by temporal instabilities, but are rather related to receiver properties.

Single-chip fully integrated direct-modulation CMOS RF transmitters for short-range wireless applications.

PubMed

El-Desouki, Munir M; Qasim, Syed Manzoor; BenSaleh, Mohammed; Deen, M Jamal

2013-08-02

Ultra-low power radio frequency (RF) transceivers used in short-range application such as wireless sensor networks (WSNs) require efficient, reliable and fully integrated transmitter architectures with minimal building blocks. This paper presents the design, implementation and performance evaluation of single-chip, fully integrated 2.4 GHz and 433 MHz RF transmitters using direct-modulation power voltage-controlled oscillators (PVCOs) in addition to a 2.0 GHz phase-locked loop (PLL) based transmitter. All three RF transmitters have been fabricated in a standard mixed-signal CMOS 0.18 µm technology. Measurement results of the 2.4 GHz transmitter show an improvement in drain efficiency from 27% to 36%. The 2.4 GHz and 433 MHz transmitters deliver an output power of 8 dBm with a phase noise of -122 dBc/Hz at 1 MHz offset, while drawing 15.4 mA of current and an output power of 6.5 dBm with a phase noise of -120 dBc/Hz at 1 MHz offset, while drawing 20.8 mA of current from 1.5 V power supplies, respectively. The PLL transmitter delivers an output power of 9 mW with a locking range of 128 MHz and consumes 26 mA from 1.8 V power supply. The experimental results demonstrate that the RF transmitters can be efficiently used in low power WSN applications.

Range and movement of resident holdover and hatchery brown trout tagged with radio transmitters in the Farmington River, Connecticut

USGS Publications Warehouse

Popoff, N.D.; Neumann, Robert M.

2005-01-01

The 5.8-km West Branch Farmington River Trout Management Area (TMA) is one of Connecticut's premier catch-and-release fisheries for brown trout Salmo trutta. However, little is known about the behavior of brown trout in this system and to what extent brown trout emigrate from the TMA. The objectives of this study were to determine the movement, range, and emigration of resident holdover and newly stocked brown trout tagged with radio transmitters in the TMA. Transmitters were implanted into 22 first-year (mean total length = 314 mm) and 25 second-year (mean total length = 432 mm) holdover brown trout. Twenty catchable-size (mean total length = 290 mm) brown trout were also implanted with transmitters and released into the TMA. The mean range (distance between the extreme upstream and downstream locations) was greater for second-year holdover brown trout than for first-year holdover brown trout, and it was greater in fall than in winter. The movement (distance moved between successive locations) of holdover brown trout was greater in fall than in winter. Movement of first-year holdover brown trout was significantly related to discharge, water temperature, and the number of days between successive locations. Newly stocked brown trout exhibited the two largest ranges (5.3 and 4.7 km). The range of newly stocked brown trout was not different between seasons, but movement was greater in spring than in summer. Through 16 weeks poststocking, there was no discernable difference in the percentage of stocked brown trout dispersing in a predominantly upstream or downstream direction. Mean dispersal distances from the stocking location were 0.5 and 0.9 km at 2 and 12 weeks poststocking, respectively. Movement of newly stocked brown trout was positively related to discharge and negatively related to water temperature. A known 6% (4 of 67) of the tagged brown trout emigrated from the TMA, but up to 21% (14 of 67) of tagged fish could have left the study area if all missing fish

47 CFR 80.911 - VHF transmitter.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false VHF transmitter. 80.911 Section 80.911 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.911 VHF...

47 CFR 80.911 - VHF transmitter.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false VHF transmitter. 80.911 Section 80.911 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.911 VHF...

47 CFR 80.911 - VHF transmitter.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false VHF transmitter. 80.911 Section 80.911 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.911 VHF...

47 CFR 80.911 - VHF transmitter.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false VHF transmitter. 80.911 Section 80.911 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.911 VHF...

Quantal Study of the Exchange Reaction for N + N2 using an ab initio Potential Energy Surface

NASA Technical Reports Server (NTRS)

Wang, Dunyou; Stallcop, James R.; Huo, Winifred M.; Dateo, Christopher E.; Schwenke, David W.; Partridge, Harry; Kwak, Dochan (Technical Monitor)

2002-01-01

The N + N2 exchange rate is calculated using a time-dependent quantum dynamics method on a newly determined ab initio potential energy surface (PES) for the ground A" state. This ab initio PES shows a double barrier feature in the interaction region with the barrier height at 47.2 kcal/mol, and a shallow well between these two barriers, with the minimum at 43.7 kcal/mol. A quantum dynamics wave packet calculation has been carried out using the fitted PES to compute the cumulative reaction probability for the exchange reaction of N + N2(J=O). The J - K shift method is then employed to obtain the rate constant for this reaction. The calculated rate constant is compared with experimental data and a recent quasi-classical calculation using a LEPS PES. Significant differences are found between the present and quasiclassical results. The present rate calculation is the first accurate 3D quantal dynamics study for N + N2 reaction system and the ab initio PES reported here is the first such surface for N3.

High Power mm-Wave Transmitter System for Radar or Telecommunications

NASA Technical Reports Server (NTRS)

Stride, S. L.; McMaster, R. L.; Pogorzelski, R. J.

2003-01-01

Future NASA deep space missions able to provide tens of kilo-watts of spacecraft DC power, make it feasible to employ high power RF telecommunications systems. Traditional flight systems (e.g., Cassini), constrained by limited DC power, used a single high-gain 4m Cassegrain reflector fed by a single lower power (20W) transmitter. Increased available DC power means that high power (1000 W) transmitters can be used. Rather than continue building traditional single-transmitter systems it now becomes feasible to engineer and build multi-element active arrays that can illuminate a dish. Illuminating a 2m dish with a spherical wavefront from an offset 1kW active array can provide sufficient ERP (Effective Radiated Power) when compared to a larger Cassegrain dish. Such a system has the advantage of lower mass, lower volume, improved reliability, less stringent pointing requirements, lower cost and risk. We propose to design and build a prototype Ka-band transmit antenna with an active sub-array using 125W TWTAs. The system could be applied to a telecommunications downlink or radar transmitter used for missions such as JIMO.

Examination of an Optical Transmittance Test for Photovoltaic Encapsulation Materials (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, D.; Bengoechea, J.; Bokria, J.

2013-09-01

The optical transmittance of encapsulation materials is a key characteristic for their use in photovoltaic (PV) modules. Changes in transmittance with time in the field affect module performance, which may impact product warranties. Transmittance is important in product development, module manufacturing, and field power production (both immediate and long-term). Therefore, an international standard (IEC 62788-1-4) has recently been proposed by the Encapsulation Task-Group within the Working Group 2 (WG2) of the International Electrotechnical Commission (IEC) Technical Committee 82 (TC82) for the quantification of the optical performance of PV encapsulation materials. Existing standards, such as ASTM E903, are general and moremore » appropriately applied to concentrated solar power than to PV. Starting from the optical transmittance measurement, the solar-weighted transmittance of photon irradiance, yellowness index (which may be used in aging studies to assess durability), and ultraviolet (UV) cut-off wavelength may all be determined using the proposed standard. The details of the proposed test are described. The results of a round-robin experiment (for five materials) conducted at seven laboratories to validate the test procedure using representative materials are also presented. For example, the Encapsulation Group actively explored the measurement requirements (wavelength range and resolution), the requirements for the spectrophotometer (including the integrating sphere and instrument accessories, such as a depolarizer), specimen requirements (choice of glass-superstrate and -substrate), and data analysis (relative to the light that may be used in the PV application). The round-robin experiment identified both intra- and inter-laboratory instrument precision and bias for five encapsulation materials (encompassing a range of transmittance and haze-formation characteristics).« less

47 CFR 61.33 - Letters of transmittal.

Code of Federal Regulations, 2010 CFR

2010-10-01

... inches (21.6 cm×27.9 cm) in size. All letters of transmittal must (1) Concisely explain the nature and... No. Secretary, Federal Communications Commission; Washington, DC 20554 Attention: Wireline...

47 CFR 22.1009 - Transmitter locations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Transmitter locations. 22.1009 Section 22.1009 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES... zones specified in § 22.1007. Offshore stations must not transmit from locations within 241 kilometers...

15. View of southeasterly side of transmitter building no. 102 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. View of southeasterly side of transmitter building no. 102 with TR in middle and small satcom communication dome lower right. Note site well system building to lower right of transmitter building no. 102 southeast corner. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

12. View from east side of corner of transmitter building ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. View from east side of corner of transmitter building no. 102 looking over top of utilidor passageway link, DR 2 antenna in background left and abandoned radome on top of transmitter building no. 101. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Evaluation of three miniature radio transmitter attachment methods for small passerines

USGS Publications Warehouse

Sykes, P.W.; Carpenter, J.W.; Holzman, S.; Geissler, P.H.

1990-01-01

Thirty-two immature common yellowthroats were used to evaluate three methods of attaching radio transmitters to the backs of small passerines: adhesive, velcro, and harness. There were no significant differences between the three methods; however, the adhesive method of transmitter attachment to small birds was found to be the preferred technique.

Nonlethal gill biopsy does not affect juvenile chinook salmon implanted with radio transmitters

USGS Publications Warehouse

Martinelli-Liedtke, T. L.; Shively, R.S.; Holmberg, G.S.; Sheer, M.B.; Schrock, R.M.

1999-01-01

Using gastric and surgical transmitter implantation, we compared radio-tagged juvenile chinook salmon Oncorhynchus tshawytscha (T(O)) with tagged fish also having a gill biopsy (T(B)) to determine biopsy effects on fish implanted with radio transmitters. We found no evidence during the 21-d period to suggest that a gill biopsy reduced survival, growth, or gross condition of the tagged-biopsy group, regardless of transmitter implantation technique. We recorded 100% survival of all treatment groups. Relative growth rates of T(O) and T(B) fish did not differ significantly. Leukocrit and lysozyme levels were not significantly different among groups, suggesting that no signs of infection were present. Our findings suggest that small chinook salmon can tolerate the combination of transmitter implantation and gill biopsy without compromising condition relative to fish receiving only the transmitter. We believe a gill biopsy can be used in field telemetry studies, especially when physiological data are needed in addition to behavioral data.

[Measurement and comparison of the spectral transmittance of cerinate porcelain and human enamel].

PubMed

Chen, Ji-Hua; Zhou, Guo-Feng; Wei, Zhang-Rui; Wang, Hui; Zhao, San-Jun

2006-12-01

To measure the spectral transmittance of Cerinate porcelain veneer and enamel in different color and different thickness. Samples of Cerinate porcelain veneers were prepared in different thickness (0.50 mm, 0.75 mm, 1.00 mm) and different Vita shade (A1, A2, A3). Enamel samples in shade A2 were made with three thickness (0.50 mm, 0.75 mm, 1.00 mm). A spectrophotometer with spectra range (380-800 nm) was employed to measure the spectral transmittance. Spectral transmittance decreased with the increasing in the thickness of specimens and decreasing in the color darkness. The transmittance of Cerinate porcelain veneer material and enamel in the same color and same thickness hadn't significant difference. The key factor to spectral transmittance of porcelain veneer materials is veneer's thickness, and the color of the materials has also some influence on it. Cerinate porcelain veneers can properly recover the transparency of teeth.

47 CFR 101.139 - Authorization of transmitters.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.139 Authorization of transmitters. (a) Unless...-point microwave and point-to-multipoint services under this part must be a type that has been verified...

47 CFR 101.139 - Authorization of transmitters.

Code of Federal Regulations, 2014 CFR

2014-10-01

... SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.139 Authorization of transmitters. (a) Unless...-point microwave and point-to-multipoint services under this part must be a type that has been verified...

47 CFR 101.139 - Authorization of transmitters.

Code of Federal Regulations, 2012 CFR

2012-10-01

... SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.139 Authorization of transmitters. (a) Unless...-point microwave and point-to-multipoint services under this part must be a type that has been verified...

47 CFR 101.139 - Authorization of transmitters.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.139 Authorization of transmitters. (a) Unless...-point microwave and point-to-multipoint services under this part must be a type that has been verified...

The 20 GHz spacecraft IMPATT solid state transmitter

NASA Technical Reports Server (NTRS)

Best, T.; Ngan, Y. C.

1986-01-01

The engineering development of a solid-state transmitter amplifier operating in the 20-GHz frequency range is described. This effort involved a multitude of disciplines including IMPATT device development, circulator design, multiple-diode circuit design, and amplifier integration and test. The objective was to develop a transmitter amplifier demonstrating the feasibility of providing an efficient, reliable, lightweight solid-state transmitter to be flown on a 30 to 20 GHz communication demonstration satellite. The work was done under contract from NASA/Lewis Research Center for a period of three years. The result was the development of a GaAs IMPACT diode amplifier capable of an 11-W CW output power and a 2-dB bandwidth of 300 MHz. GaAs IMPATT diodes incorporating diamond heatsink and double-Read doping profile capable of 5.3-W CW oscillator output power and 15.5% efficiency were developed. Up to 19% efficiency was also observed for an output power level of 4.4 W. High performance circulators with a 0.2 dB inserting loss and bandwidth of 5 GHz have also been developed. These represent a significant advance in both device and power combiner circuit technologies in K-band frequencies.

Hydrodynamic effect of a satellite transmitter on a juvenile green turtle (Chelonia mydas)

PubMed

Watson; Granger

1998-09-01

Wind tunnel tests were performed to measure the effect of a satellite transmitter on a juvenile green turtle (Chelonia mydas). A full-scale turtle model was constructed from an 11.5 kg specimen with a 48 cm carapace length, and a transmitter model was constructed from a Telonics ST-6. The turtle model was tested in a wind tunnel with and without the transmitter, which was mounted on the forward, topmost part of the carapace. Drag, lift and pitch moment were measured for several speeds and flow angles, and the data were scaled for application to the marine environment. At small flow angles representative of straight-line swimming, the transmitter increased drag by 27-30 %, reduced lift by less than 10 % and increased the pitch moment by 11-42 %. On the basis of the drag data at zero angle of attack, it is estimated that the backpack will reduce swimming speed by 11 %, assuming that the turtle produces the same thrust with the unit attached. The drag data are also used to estimate the effect of a transmitter on the swimming energetics of an adult green turtle. Design guidelines are included to minimize the adverse forces and moments caused by the transmitter.

High-energy, 2µm laser transmitter for coherent wind LIDAR

NASA Astrophysics Data System (ADS)

Singh, Upendra N.; Yu, Jirong; Kavaya, Michael J.; Koch, Grady J.

2017-11-01

A coherent Doppler lidar at 2μm wavelength has been built with higher output energy (300 mJ) than previously available. The laser transmitter is based on the solid-state Ho:Tm:LuLiF, a NASA Langley Research Center invented laser material for higher extraction efficiency. This diode pumped injection seeded MOPA has a transform limited line width and diffraction limited beam quality. NASA Langley Research Center is developing coherent wind lidar transmitter technology at eye-safe wavelength for satellite-based observation of wind on a global scale. The ability to profile wind is a key measurement for understanding and predicting atmospheric dynamics and is a critical measurement for improving weather forecasting and climate modeling. We would describe the development and performance of an engineering hardened 2μm laser transmitter for coherent Doppler wind measurement from ground/aircraft/space platform.

α‐Conotoxin M1 (CTx) blocks αδ binding sites of adult nicotinic receptors while ACh binding at αε sites elicits only small and short quantal synaptic currents

PubMed Central

Dudel, Josef

2014-01-01

Abstract In ‘embryonic’ nicotinic receptors, low CTx concentrations are known to block only the αδ binding site, whereas binding of ACh at the αγ‐site elicits short single channel openings and short bursts. In adult muscles the αγ‐ is replaced by the αε‐site. Quantal EPSCs (qEPSCs) were elicited in adult muscles by depolarization pulses and recorded through a perfused macropatch electrode. One to 200 nmol L−1 CTx reduced amplitudes and decay time constants of qEPSCs, but increased their rise times. CTx block at the αδ binding sites was incomplete: The qEPSCs still contained long bursts from not yet blocked receptors, whereas their average decay time constants were reduced by a short burst component generated by ACh binding to the αε‐site. Two nanomolar CTx applied for 3 h reduced the amplitudes of qEPSCs to less than half with a constant slope. The equilibrium concentration of the block is below 1 nmol L−1 and lower than that of embryonic receptors. CTx‐block increased in proportion to CTx concentrations (average rate 2 × 104 s−1·mol−1 L). Thus, the reactions of ‘embryonic’ and of adult nicotinic receptors to block by CTx are qualitatively the same. – The study of the effects of higher CTx concentrations or of longer periods of application of CTx was limited by presynaptic effects of CTx. Even low CTx concentrations severely reduced the release of quanta by activating presynaptic M2 receptors at a maximal rate of 6 × 105 s−1·mol−1 L. When this dominant inhibition was prevented by blocking the M2 receptors with methoctramine, activation of M1 receptors was unmasked and facilitated release. PMID:25501436

14. View of southerly side of transmitter building no. 101 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. View of southerly side of transmitter building no. 101 from west looking easterly showing radar scanner building no. 104 to right with passageway link between, abandoned radome on top of transmitter building no. 101 and DR 1 antenna in background. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Piezoelectric transducer design for a miniaturized injectable acoustic transmitter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Huidong; Jung, Ki Won; Deng, Zhiqun D.

Acoustic telemetry has been an important tool in the last 20 years for studying fish survival and migration behaviors during and after dam passage. This technology uses implantable acoustic transmitters as tags to three-dimensionally track the movement of fish. However, the relatively large weights and sizes of commercially available transmitters limit the populations of fish that could be studied. The surgical implantation procedures required may also injure fish and also incur a significant amount of labor. Therefore, a smaller, lighter, and injectable tag was needed, and similar or better acoustic performance and service life over that provided by existing commercialmore » tags was desired. To develop such a small transmitter, a number of technical challenges, including design optimization of the piezoelectric transducer, needed to be overcome. The goal of our efforts to optimize the transducer focused on improving the average source level in the 180° range in which the transmitter was facing the receiving hydrophone, so as to increase the transmitter’s detection probability. This paper reports the techniques that were explored and developed to achieve this goal. We found that a novel off-center tube transducer improved the average source level of the front half of the transducer by 1.5 dB. An acoustic reflector attached to the back of the transducer also improved the source level by 3 dB when the transducer was pointed toward the receiving hydrophone, although the source level on the sides of the transducer was reduced. We found that too small a gap between the transducer and the component placed behind it resulted in distortion of the beam pattern. To overcome that issue, we connected a tuning inductor in series with the transducer to help optimize the source level. Furthermore, the findings and techniques developed in this work contributed to the successful development and implementation of a new injectable transmitter.« less

Piezoelectric transducer design for a miniaturized injectable acoustic transmitter

DOE PAGES

Li, Huidong; Jung, Ki Won; Deng, Zhiqun D.

2015-10-07

Acoustic telemetry has been an important tool in the last 20 years for studying fish survival and migration behaviors during and after dam passage. This technology uses implantable acoustic transmitters as tags to three-dimensionally track the movement of fish. However, the relatively large weights and sizes of commercially available transmitters limit the populations of fish that could be studied. The surgical implantation procedures required may also injure fish and also incur a significant amount of labor. Therefore, a smaller, lighter, and injectable tag was needed, and similar or better acoustic performance and service life over that provided by existing commercialmore » tags was desired. To develop such a small transmitter, a number of technical challenges, including design optimization of the piezoelectric transducer, needed to be overcome. The goal of our efforts to optimize the transducer focused on improving the average source level in the 180° range in which the transmitter was facing the receiving hydrophone, so as to increase the transmitter’s detection probability. This paper reports the techniques that were explored and developed to achieve this goal. We found that a novel off-center tube transducer improved the average source level of the front half of the transducer by 1.5 dB. An acoustic reflector attached to the back of the transducer also improved the source level by 3 dB when the transducer was pointed toward the receiving hydrophone, although the source level on the sides of the transducer was reduced. We found that too small a gap between the transducer and the component placed behind it resulted in distortion of the beam pattern. To overcome that issue, we connected a tuning inductor in series with the transducer to help optimize the source level. Furthermore, the findings and techniques developed in this work contributed to the successful development and implementation of a new injectable transmitter.« less

Neuromuscular paralysis by the basic phospholipase A2 subunit of crotoxin from Crotalus durissus terrificus snake venom needs its acid chaperone to concurrently inhibit acetylcholine release and produce muscle blockage.

PubMed

Cavalcante, Walter L G; Noronha-Matos, José B; Timóteo, Maria A; Fontes, Marcos R M; Gallacci, Márcia; Correia-de-Sá, Paulo

2017-11-01

Crotoxin (CTX), a heterodimeric phospholipase A 2 (PLA 2 ) neurotoxin from Crotalus durissus terrificus snake venom, promotes irreversible blockade of neuromuscular transmission. Indirect electrophysiological evidence suggests that CTX exerts a primary inhibitory action on transmitter exocytosis, yet contribution of a postsynaptic action of the toxin resulting from nicotinic receptor desensitization cannot be excluded. Here, we examined the blocking effect of CTX on nerve-evoked transmitter release measured directly using radioisotope neurochemistry and video microscopy with the FM4-64 fluorescent dye. Experiments were conducted using mice phrenic-diaphragm preparations. Real-time fluorescence video microscopy and liquid scintillation spectrometry techniques were used to detect transmitter exocytosis and nerve-evoked [ 3 H]-acetylcholine ([ 3 H]ACh) release, respectively. Nerve-evoked myographic recordings were also carried out for comparison purposes. Both CTX (5μg/mL) and its basic PLA 2 subunit (CB, 20μg/mL) had biphasic effects on nerve-evoked transmitter exocytosis characterized by a transient initial facilitation followed by a sustained decay. CTX and CB reduced nerve-evoked [ 3 H]ACh release by 60% and 69%, respectively, but only the heterodimer, CTX, decreased the amplitude of nerve-evoked muscle twitches. Data show that CTX exerts a presynaptic inhibitory action on ACh release that is highly dependent on its intrinsic PLA 2 activity. Given the high safety margin of the neuromuscular transmission, one may argue that the presynaptic block caused by the toxin is not enough to produce muscle paralysis unless a concurrent postsynaptic inhibitory action is also exerted by the CTX heterodimer. Copyright © 2017. Published by Elsevier Inc.

47 CFR 90.473 - Operation of internal transmitter control systems through licensed fixed control points.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operation of internal transmitter control systems through licensed fixed control points. 90.473 Section 90.473 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control...

47 CFR 90.473 - Operation of internal transmitter control systems through licensed fixed control points.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Operation of internal transmitter control systems through licensed fixed control points. 90.473 Section 90.473 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control...

47 CFR 90.473 - Operation of internal transmitter control systems through licensed fixed control points.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Operation of internal transmitter control systems through licensed fixed control points. 90.473 Section 90.473 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control...

47 CFR 90.473 - Operation of internal transmitter control systems through licensed fixed control points.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Operation of internal transmitter control systems through licensed fixed control points. 90.473 Section 90.473 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control...

47 CFR 90.473 - Operation of internal transmitter control systems through licensed fixed control points.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Operation of internal transmitter control systems through licensed fixed control points. 90.473 Section 90.473 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control...

Integration and test of high-speed transmitter electronics for free-space laser communications

NASA Technical Reports Server (NTRS)

Soni, Nitin J.; Lizanich, Paul J.

1994-01-01

The NASA Lewis Research Center in Cleveland, Ohio, has developed the electronics for a free-space, direct-detection laser communications system demonstration. Under the High-Speed Laser Integrated Terminal Electronics (Hi-LITE) Project, NASA Lewis has built a prototype full-duplex, dual-channel electronics transmitter and receiver operating at 325 megabit S per second (Mbps) per channel and using quaternary pulse-position modulation (QPPM). This paper describes the integration and testing of the transmitter portion for future application in free-space, direct-detection laser communications. A companion paper reviews the receiver portion of the prototype electronics. Minor modifications to the transmitter were made since the initial report on the entire system, and this paper addresses them. The digital electronics are implemented in gallium arsenide integrated circuits mounted on prototype boards. The fabrication and implementation issues related to these high-speed devices are discussed. The transmitter's test results are documented, and its functionality is verified by exercising all modes of operation. Various testing issues pertaining to high-speed circuits are addressed. A description of the transmitter electronics packaging concludes the paper.

47 CFR 15.212 - Modular transmitters.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 1 2013-10-01 2013-10-01 false Modular transmitters. 15.212 Section 15.212 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.212... powered, it must comply with the AC line conducted requirements found in § 15.207. AC or DC power lines...

47 CFR 15.212 - Modular transmitters.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Modular transmitters. 15.212 Section 15.212 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.212... powered, it must comply with the AC line conducted requirements found in § 15.207. AC or DC power lines...

47 CFR 15.212 - Modular transmitters.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 1 2011-10-01 2011-10-01 false Modular transmitters. 15.212 Section 15.212 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.212... powered, it must comply with the AC line conducted requirements found in § 15.207. AC or DC power lines...

47 CFR 15.212 - Modular transmitters.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 1 2012-10-01 2012-10-01 false Modular transmitters. 15.212 Section 15.212 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.212... powered, it must comply with the AC line conducted requirements found in § 15.207. AC or DC power lines...

47 CFR 15.212 - Modular transmitters.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 1 2014-10-01 2014-10-01 false Modular transmitters. 15.212 Section 15.212 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators § 15.212... powered, it must comply with the AC line conducted requirements found in § 15.207. AC or DC power lines...

47 CFR 80.911 - VHF transmitter.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., and on the ship-to-shore working frequencies necessary to communicate with public coast stations... transmission of speech normally produces peak modulation within the limits 75 percent and 100 percent. (c) The transmitter must be certificated to transmit between 20 watts and 25 watts, on each of the frequencies 156.300...

Synergy of adaptive thresholds and multiple transmitters in free-space optical communication.

PubMed

Louthain, James A; Schmidt, Jason D

2010-04-26

Laser propagation through extended turbulence causes severe beam spread and scintillation. Airborne laser communication systems require special considerations in size, complexity, power, and weight. Rather than using bulky, costly, adaptive optics systems, we reduce the variability of the received signal by integrating a two-transmitter system with an adaptive threshold receiver to average out the deleterious effects of turbulence. In contrast to adaptive optics approaches, systems employing multiple transmitters and adaptive thresholds exhibit performance improvements that are unaffected by turbulence strength. Simulations of this system with on-off-keying (OOK) showed that reducing the scintillation variations with multiple transmitters improves the performance of low-frequency adaptive threshold estimators by 1-3 dB. The combination of multiple transmitters and adaptive thresholding provided at least a 10 dB gain over implementing only transmitter pointing and receiver tilt correction for all three high-Rytov number scenarios. The scenario with a spherical-wave Rytov number R=0.20 enjoyed a 13 dB reduction in the required SNR for BER's between 10(-5) to 10(-3), consistent with the code gain metric. All five scenarios between 0.06 and 0.20 Rytov number improved to within 3 dB of the SNR of the lowest Rytov number scenario.

The deep-tow marine controlled-source electromagnetic transmitter system for gas hydrate exploration

NASA Astrophysics Data System (ADS)

Wang, Meng; Deng, Ming; Wu, Zhongliang; Luo, Xianhu; Jing, Jianen; Chen, Kai

2017-02-01

The Marine Controlled-Source Electromagnetic (MCSEM) method has been recognized as an important and effective tool to detect electrically resistive structures, such as oil, gas, and gas hydrate. The MCSEM performance is strongly influenced by the transmitter system design. We have developed a deep-tow MCSEM transmitter system. In this paper, some new technical details will be present. A 10,000 m optical-electrical composite cable is used to support high power transmission and fast data transfer; a new clock unit is designed to keep the synchronization between transmitter and receivers, and mark the time stamp into the transmission current full waveform; a data link is established to monitor the real-time altitude of the tail unit; an online insulation measuring instrument is adopted to monitor current leakage from high voltage transformer; a neutrally buoyant dipole antenna of copper cable and flexible electrodes are created to transmit the large power current into seawater; a new design method for the transmitter, which is called "real-time control technology of hardware parallelism", is described to achieve inverting and recording high-power current waveform, controlling functions, and collecting auxiliary information. We use a gas hydrate exploration test to verify the performance of the transmitter system, focusing on more technical details, rather than applications. The test shows that the transmitter can be used for gas hydrate exploration as an effective source.

Effects of implanted radio transmitters with percutaneous antennas on the behavior of Canada Geese

USGS Publications Warehouse

Hupp, Jerry W.; Ruhl, G.A.; Pearce, John M.; Mulcahy, Daniel M.; Tomeo, M.A.

2003-01-01

We examined whether surgically-implanted radio transmitters with percutaneous antennas affected behavior of Lesser Canada Geese (Branta canadensis parvipes) in Anchorage, Alaska. We implanted either a 26-g VHF radio transmitter or a larger VHF radio that was the same mass (35 g) and shape as a satellite transmitter in the coelom of adult females captured during molt in 2000. A control group of females was marked with leg bands. We simultaneously observed behavior of radio-marked and control females from 4-62 d following capture. We observed no differences in the proportion of time birds in different treatments allocated among grazing, resting, comfort, walking, and alert behavior. Females in different treatments spent a similar proportion of time in the water. Implantation of radio transmitters did not affect the frequency of agonistic interactions. We conclude that coelomic radio transmitters with percutaneous antennas had minimal effects on the behavior of Canada Geese.

Transmittance and scattering during wound healing after refractive surgery

NASA Astrophysics Data System (ADS)

Mar, Santiago; Martinez-Garcia, C.; Blanco, J. T.; Torres, R. M.; Gonzalez, V. R.; Najera, S.; Rodriguez, G.; Merayo, J. M.

2004-10-01

Photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) are frequent techniques performed to correct ametropia. Both methods have been compared in their way of healing but there is not comparison about transmittance and light scattering during this process. Scattering in corneal wound healing is due to three parameters: cellular size and density, and the size of scar. Increase in the scattering angular width implies a decrease the contrast sensitivity. During wound healing keratocytes activation is induced and these cells become into fibroblasts and myofibroblasts. Hens were operated using PRK and LASIK techniques. Animals used in this experiment were euthanized, and immediately their corneas were removed and placed carefully into a cornea camera support. All optical measurements have been done with a scatterometer constructed in our laboratory. Scattering measurements are correlated with the transmittance -- the smaller transmittance is the bigger scattering is. The aim of this work is to provide experimental data of the corneal transparency and scattering, in order to supply data that they allow generate a more complete model of the corneal transparency.

VLBI Observations of ALSEP Transmitters

NASA Technical Reports Server (NTRS)

Counselman, C. C.

1977-01-01

The technique of differential very-long-baseline inteferometry (VLBI) Apollo Lunar Surface Experiments Package was used to measure the relative positions of the (ALSEP) transmitters at the Apollo 12, 14, 15, 16, and 17 lunar landing sites with uncertainties less than 0.005 sec of the geocentric arc. These measurements yielded improved determinations of the selenodetic coordinates of the Apollo landing sites, and of the physical libration of the moon.

Predicting transmittance spectra of electrophotographic color prints

NASA Astrophysics Data System (ADS)

Mourad, Safer; Emmel, Patrick; Hersch, Roger D.

2000-12-01

For dry toner electrophotographic color printers, we present a numerical simulation model describing the color printer responses based on a physical characterization of the different electrophotographic process steps. The proposed model introduces a Cross Transfer Efficiency designed to predict the color transmittance spectra of multi-color prints by taking into account the transfer influence of each deposited color toner layer upon the other layers. The simulation model leads to a better understanding of the factors that have an impact on printing quality. In order to avoid the additional optical non-linearities produced by light reflection on paper, we have limited the present investigation to transparency prints. The proposed model succeeded to predict the transmittance spectra of printed wedges combining two color toner layers with a mean deviation less than CIE-LAB (Delta) E equals 2.5.

Tunable transmittance in anisotropic two-dimensional materials

NASA Astrophysics Data System (ADS)

Nualpijit, Phusit; Sinner, Andreas; Ziegler, Klaus

2018-06-01

A uniaxial strain applied to graphenelike materials moves the Dirac nodes along the boundary of the Brillouin zone. An extreme case is the merging of the Dirac node positions to a single degenerate spectral node, which gives rise to a new topological phase. Then isotropic Dirac nodes are replaced by a node with a linear behavior in one and a parabolic behavior in the other direction. This anisotropy influences substantially the optical properties. We propose a method to determine characteristic spectral and transport properties in black phosphorus layers, which were recently studied by several groups with angle-resolved photoemission spectroscopy, and discuss how the transmittance, the reflectance, and the optical absorption of this material can be tuned. In particular, we demonstrate that the transmittance of linearly polarized incident light varies from nearly 0% to almost 100% in the microwave and far-infrared regime.

Calculating Solar Ultraviolet Irradiation Of The Human Cornea And Corresponding Required Sunglass Lens Transmittances

NASA Astrophysics Data System (ADS)

Hoover, Herbert L.; Marsaud, Serge G.

1986-05-01

Tinted ophthalmic lenses are used primarily for eye comfort in a brightly lit environment. An ancillary benefit is the attenuation of ultraviolet radiation. Some national product standards specify quantitative limits for ultraviolet transmittances. Such limits ought to be founded on quantitative estimates of solar irradiances of ocular tissues, with actinic effectiveness taken into account. We use the equations of Green and coworkers for direct and diffuse solar irradiance at the earth's surface to calculate average sky and ground spectral radiances. We use the geometric factors derived by us for the coupling of radiation from these sources to the human cornea. Actinically weighted corneal spectral irradiances integrated over wavelength and time yield peak irradiances and accumulated exposure doses that are compared with recommended exposure limits. This provides the maximal effective ultraviolet transmittances of tinted ophthalmic lenses such that these exposure limits will not be exceeded in the selected exposure environment. The influences on corneal irradiation of such exposure parameters as solar zenith angle, altitude of the exposure site, characteristics of atmospheric aerosols, and ground reflectances are illustrated. The relationships between the effective transmittance (which is a function of the environmental radiation and any actinicweighting function) and readily determined characteristics of the lens itself, viz., its mean transmittance, and a selected spectral transmittance, are derived for three lens transmittance curves. Limits of lens transmittance for the UV-B and UV-A wavelength regions are presented for several representative exposure sites in Europe and the U.S.A.

View of Signal Corps Radar (S.C.R.) 296 Station 5 Transmitter ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of Signal Corps Radar (S.C.R.) 296 Station 5 Transmitter Building foundation, showing Fire Control Stations (Buildings 621 and 622) and concrete stairway (top left) camera facing southwest - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

An uncovered risk factor of sonothrombolysis: Substantial fluctuation of ultrasound transmittance through the human skull.

PubMed

Wang, Zuojun; Komatsu, Teppei; Mitsumura, Hidetaka; Nakata, Norio; Ogawa, Takeki; Iguchi, Yasuyuki; Yokoyama, Masayuki

2017-05-01

Sonothrombolysis is one of the most feasible methods for enhancing clot lysis with a recombinant tissue plasminogen activator (rt-PA) in cases of acute ischemic strokes. For safe and efficient clinical practices of sonothrombolysis, accurate estimation of ultrasound transmittance through the human skull is critical. Previously, we reported substantial and periodic fluctuation of ultrasound transmittance through a bone-phantom plate following changes to ultrasound frequency, the thickness of the bone-phantom plate, and the distance between a transducer and the bone-phantom plate. In the present study, we clarify the transmittance behavior of medium-frequency ultrasound (from 400kHz to 600kHz) through the human skull, and examine reduction of the transmittance fluctuation. For the study, we measured transmittance of sinusoidal ultrasound waves at 400kHz, 500kHz, and 600kHz at 13 temple spots on 3 human skulls by changing the distance between a transducer and the skull bone, and found substantial and periodic fluctuation in the transmittance behaviors for these sinusoidal voltage excitations. Degrees of the fluctuation varied depending on the measurement spots. A fluctuation ratio between the maximum transmittance and the minimum transmittance reached 3 in some spots. This large transmittance fluctuation is considered to be a risk factor for sonothrombolysis therapies. We examined a modulated ultrasound wave to reduce the fluctuation, and succeeded in obtaining considerable reduction. The average fluctuation ratios for 400-kHz, 500-kHz, and 600-kHz waves were 2.38, 2.38, and 2.07, respectively. We successfully reduced the ratio to 1.72 by using a periodic selection of random frequency (PSRF)-type of modulation wave. The thus obtained results indicate that attention to the fluctuation in ultrasound transmittance through the skull is necessary for safe and effective sonothrombolysis therapies, and that modulated ultrasound waves constitute a powerful method for reducing

Integrated Inductors for RF Transmitters in CMOS/MEMS Smart Microsensor Systems

PubMed Central

Kim, Jong-Wan; Takao, Hidekuni; Sawada, Kazuaki; Ishida, Makoto

2007-01-01

This paper presents the integration of an inductor by complementary metal-oxide-semiconductor (CMOS) compatible processes for integrated smart microsensor systems that have been developed to monitor the motion and vital signs of humans in various environments. Integration of radio frequency transmitter (RF) technology with complementary metal-oxide-semiconductor/micro electro mechanical systems (CMOS/MEMS) microsensors is required to realize the wireless smart microsensors system. The essential RF components such as a voltage controlled RF-CMOS oscillator (VCO), spiral inductors for an LC resonator and an integrated antenna have been fabricated and evaluated experimentally. The fabricated RF transmitter and integrated antenna were packaged with subminiature series A (SMA) connectors, respectively. For the impedance (50 Ω) matching, a bonding wire type inductor was developed. In this paper, the design and fabrication of the bonding wire inductor for impedance matching is described. Integrated techniques for the RF transmitter by CMOS compatible processes have been successfully developed. After matching by inserting the bonding wire inductor between the on-chip integrated antenna and the VCO output, the measured emission power at distance of 5 m from RF transmitter was -37 dBm (0.2 μW).

Design of a fiber-optic transmitter for microwave analog transmission with high phase stability

NASA Technical Reports Server (NTRS)

Logan, R. T., Jr.; Lutes, G. F.; Primas, L. E.; Maleki, L.

1990-01-01

The principal considerations in the design of fiber-optic transmitters for highly phase-stable radio frequency and microwave analog transmission are discussed. Criteria for a fiber-optic transmitter design with improved amplitude and phase-noise performance are developed through consideration of factors affecting the phase noise, including low-frequency laser-bias supply noise, the magnitude and proximity of external reflections into the laser, and temperature excursions of the laser-transmitter package.

White Nail Radio Transmitter: Billion Dollar Savings through Energy Efficiency

DTIC Science & Technology

2011-05-10

increase efficiency and reduce overall energy consumption ashore by 50 percent CNO, Navy Energy Vision, P 10 White Nail Vision Your Cell Phone Cell...Estimated Total Number of transmitters 3,000,000 Estimated total power saved Watt 1,250,000,000 Cell Phone Transmitter Efficiency 1.25 Gigawatts saved...Greenhouse Gas Power 4 1 Energy Navy Use 7.3 Billion kWh White Nail Cell Phone Savings 11 Billion kWh One and a half times!!! Saves the output of four of

92. View of transmitter building no. 102 first floor coolant ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

92. View of transmitter building no. 102 first floor coolant process water tanks (sodium bisulfate solution), stainless steel, for electronic systems cooling in transmitter and MIP rooms. RCA Services Company 29 September, 1960, official photograph BMEWS Project by unknown photograph, Photographic Services, Riverton, NJ, BMEWS, clear as negative no. A-1226 - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Radio-transmitters have no impact on survival of pre-fledged American Woodcocks

USGS Publications Warehouse

Daly, Kyle O.; Andersen, David E.; Brininger, Wayne L.; Cooper, Thomas R.

2015-01-01

American Woodcocks (Scolopax minor) are a high priority species of conservation need across most of their breeding range due to long-term population declines. Survival of juveniles may be key to understanding these population declines, but there have been few direct estimates of juvenile woodcock survival rates, and no recent assessment of the possible effect of radio-tagging on juvenile survival. In 2011 and 2012, we radio-tagged 73 juvenile American Woodcocks in west-central Minnesota and compared survival rates of radio-tagged (N = 58) and non-radio-tagged (N = 82) juveniles during the period from hatching to fledging. We compared survival rates of juveniles with known fates and used logistic-exposure models to assess the potential impact of radio-transmitters on survival. We evaluated variables related to juvenile survival including age, hatch date, maximum and minimum temperature, precipitation, and year to assess the possible effects of radio-transmitters. The best-supported model of survival rate of juvenile American Woodcocks included the interaction of age and year and a negative effect of precipitation (β = −0.76, 85% CI: −1.08 to −0.43), but did not include a negative effect of transmitters. Our results suggest that radio-transmitters did not impact survival of juvenile American Woodcocks and that transmitters are a reliable tool for studying survival of juvenile American Woodcocks, and perhaps other precocial shorebirds.

Transmission between type II hair cells and bouton afferents in the turtle posterior crista.

PubMed

Holt, Joseph C; Xue, Jin-Tang; Brichta, Alan M; Goldberg, Jay M

2006-01-01

Synaptic activity was recorded with sharp microelectrodes during rest and during 0.3-Hz sinusoidal stimulation from bouton afferents identified by their efferent-mediated inhibitory responses. A glutamate antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) decreased quantal size (qsize) while lowering external Ca(2+) decreased quantal rate (qrate). Miniature excitatory postsynaptic potentials (mEPSPs) had effective durations (qdur) of 3.5-5 ms. Their timing was consistent with Poisson statistics. Mean qsizes ranged in different units from 0.25 to 0.73 mV and mean qrates from 200 to 1,500/s; there was an inverse relation across the afferent population between qrate and qsize. qsize distributions were consistent with the independent release of variable-sized quanta. Channel noise, measured during AMPA-induced depolarizations, was small compared with quantal noise. Excitatory responses were larger than inhibitory responses. Peak qrates, which could approach 3,000/s, led peak excitatory mechanical stimulation by 40 degrees . Quantal parameters varied with stimulation phase with qdur and qsize being maximal during inhibitory stimulation. Voltage modulation (vmod) was in phase with qrate and had a peak depolarization of 1.5-3 mV. On average, 80% of vmod was accounted for by quantal activity; the remaining 20% was a nonquantal component that persisted in the absence of quantal activity. The extracellular accumulation of glutamate and K(+) are potential sources of nonquantal transmission and may provide a basis for the inverse relation between qrate and qsize. Comparison of the phases of synaptic and spike activity suggests that both presynaptic and postsynaptic mechanisms contribute to variations across afferents in the timing of spikes during sinusoidal stimulation.

The Geoscience Laser Altimeter System Laser Transmitter

NASA Technical Reports Server (NTRS)

Afzal, R. S.; Dallas, J. L.; Yu, A. W.; Mamakos, W. A.; Lukemire, A.; Schroeder, B.; Malak, A.

2000-01-01

The Geoscience Laser Altimeter System (GLAS), scheduled to launch in 2001, is a laser altimeter and lidar for tile Earth Observing System's (EOS) ICESat mission. The laser transmitter requirements, design and qualification test results for this space- based remote sensing instrument are presented.

Pulsed 2-micron Laser Transmitter For Carbon Dioxide Sensing From Space

NASA Astrophysics Data System (ADS)

Singh, U. N.; Yu, J.; Bai, Y.; Petros, M.

2011-12-01

Carbon dioxide (CO2) has been recognized as one of the most important greenhouse gases. It is essential for the study of global warming to accurately measure the CO2 concentration in the atmosphere and continuously record its variation. Studies of the carbon cycle are limited by the tools available to precisely measure CO2 concentrations by remote sensing. Active sensing, using the Integrated Path Differential Absorption (IPDA) approach, permits measurements day and night, at all latitudes and seasons. The development of a high pulse energy 2-μm laser transmitter for high-precision CO2 measurements from space leverages years of NASA investment in solid-state laser technology. Under NASA Laser Risk Reduction Program, funded by Earth Science Technology Office, researchers at NASA Langley Research Center developed an injection seeded, high repetition rate, Q-switched Ho:YLF laser transmitter for CO2 Differential Absorption Lidar/IPDA (profile/column) measurements from ground and airborne platforms. This master-slave laser system has high optical-to-optical efficiency and seeding success rate. NASA LaRC's 2-micron pulsed laser transmitter possesses advantages over current passive and CW active sensors. First, the pulsed format provides a built-in means for determining range to the scattering target and effectively filtering out the scattering from thin clouds and aerosols, thus eliminating a source of measurement bias. Second, by concentrating the laser energy into a pulse, sufficient backscatter signal strength can be obtained from aerosol scattering rather than relying on a hard target at a known distance. Third, the absorption line at the 2.05 μm band is ideally suited for the CO2 concentration measurement. In particular, the weighting function of 2 μm is optimum for measurement in the lower troposphere where the sources and sinks of CO2 are located. The planned laser transmitter development will lead to a Tm:Fiber pumped Ho:YLF laser transmitter capable of

Development of external and neutrally buoyant acoustic transmitters for turbine passage evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Zhiqun; Brown, Richard S.; Carlson, Thomas J.

Recent studies show transmitters surgically implanted into juvenile salmonids, for the purposes of estimating survival of fish passing through turbines, increases the risk of injury and mortality due to the presence of the tag and exposure to rapid turbine pressure changes. Neutrally buoyant external tags may instead be used to eliminate this bias. However, the externally tagged fish could be affected by other factors such as shear and turbulence which may also bias survival estimates. Studies have been conducted to examine the influence of shear and turbulence on non-tagged juvenile salmonids, however, tests have never been conducted in the laboratorymore » or field to determine the influence of shear and turbulence on retention and injury related to attachment of external transmitters. We designed and manufactured two different configurations of neutrally buoyant (nearly zero g weight in water) external transmitters: Type A and Type B. The Type A transmitters weigh approximately 0.60 g in air and are attached to fish using two sutures anterior to the dorsal fin. The Type B transmitters weigh approximately 0.83 g in air and consist of battery part and transducer part with both parts neutrally buoyant. They are attached to both sides of the dorsal fin using two enamel coated 25 gauge magnet wires. This study provides a broad approach using evaluation measures such as holding, swimming performance, shear, turbulence, rapid decompression exposures, and predation to determine the efficacy of using neutrally buoyant external transmitters to estimate survival of juvenile salmonids passing through turbines. Preliminary results show the Type A design is a viable design for turbine passage evaluation and is being planned for field deployment in the near future.« less

Single Frequency, Pulsed Laser Diode Transmitter for Dial Water Vapor Measurements at 935nm

NASA Technical Reports Server (NTRS)

Switzer, Gregg W.; Cornwell, Donald M., Jr.; Krainak, Michael A.; Abshire, James B.; Rall, Johnathan A. R.

1998-01-01

We report a tunable, single frequency, narrow linewidth, pulsed laser diode transmitter at 935.68nm for remote sensing of atmospheric water vapor. The transmitter consists of a CW, tunable, external cavity diode laser whose output is amplified 2OdB using a tapered diode amplifier. The output is pulsed for range resolved DIAL lidar by pulsing the drive current to the diode amplifier at 4kHz with a .5% duty cycle. The output from the transmitter is 36OnJ/pulse and is single spatial mode. It maintains a linewidth of less than 25MHz as its wavelength is tuned across the water vapor absorption line at 935.68nm. The transmitter design and its use in a water vapor measurement will be discussed.

Effects of satellite transmitters on captive and wild mallards

USGS Publications Warehouse

Kesler, Dylan C.; Raedeke, Andrew H.; Foggia, Jennifer R.; Beatty, William S.; Webb, Elisabeth B.; Humburg, Dale D.; Naylor, Luke W.

2014-01-01

Satellite telemetry has become a leading method for studying large-scale movements and survival in birds, yet few have addressed potential effects of the larger and heavier tracking equipment on study subjects. We simultaneously evaluated effects of satellite telemetry equipment on captive and wild mallards (Anas platyrhynchos) to assess impacts on behavior, body mass, and movement. We randomly assigned 55 captive ducks to one of 3 treatment groups, including a standard body harness group, a modified harness group, and a control group. Ducks in the control group were not fitted with equipment, whereas individuals in the other 2 groups were fitted with dummy transmitters attached with a Teflon ribbon harness or with a similar harness constructed of nylon cord. At the conclusion of the 14-week captive study, mean body mass of birds in the control group was 40–105 g (95% CI) greater than birds with standard harnesses, and 28–99 g (95% CI) greater than birds with modified harnesses. Further, results of focal behavior observations indicated ducks with transmitters were less likely to be in water than control birds. We also tested whether movements of wild birds marked with a similar Teflon harness satellite transmitter aligned with population movements reported by on-the-ground observers who indexed local abundances of mid-continent mallards throughout the non-breeding period. Results indicated birds marked with satellite transmitters moved concurrently with the larger unmarked population. Our results have broad implications for field research and suggest that investigators should consider potential for physiological and behavioral effects brought about by tracking equipment. Nonetheless, results from wild ducks indicate satellite telemetry has the potential to provide useful movement data.

7 CFR 47.21 - Transmittal of record.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Transmittal of record. 47.21 Section 47.21 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... exhibits filed therein; any statements or stipulations filed under the documentary procedure; any documents...

Perturbations of ionosphere-magnetosphere coupling by powerful VLF emissions from ground-based transmitters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belov, A. S., E-mail: alexis-belov@yandex.ru; Markov, G. A.; Ryabov, A. O.

The characteristics of the plasma-wave disturbances stimulated in the near-Earth plasma by powerful VLF radiation from ground-based transmitters are investigated. Radio communication VLF transmitters of about 1 MW in power are shown to produce artificial plasma-wave channels (density ducts) in the near-Earth space that originate in the lower ionosphere above the disturbing emission source and extend through the entire ionosphere and magnetosphere of the Earth along the magnetic field lines. Measurements with the onboard equipment of the DEMETER satellite have revealed that under the action of emission from the NWC transmitter, which is one of the most powerful VLF radiomore » transmitters, the generation of quasi-electrostatic (plasma) waves is observed on most of the satellite trajectory along the disturbed magnetic flux tube. This may probably be indicative of stimulated emission of a magnetospheric maser.« less

Transmittance of tinted and UV-blocking disposable contact lenses.

PubMed

Harris, M G; Haririfar, M; Hirano, K Y

1999-03-01

Tinted and ultraviolet (UV)-blocking disposable contact lenses have become increasingly popular over the last decade. Wearers of UV-blocking contact lenses could benefit greatly by protecting their eyes from potential UV radiation damage. A Uvikon 930 dual beam spectrophotometer was used to measure three enhancement-tinted lenses (royal blue, evergreen, and aqua), two types of UV-blocking lenses, and two types of non-UV-blocking lenses. Enhancement-tinted lenses did show a decrease in transmittance at certain wavelengths on the visible spectrum, but they did not reduce the transmittance of UV radiation to the extent of the UV-blocking lenses designed specifically for this purpose.

Inductance effects in the high-power transmitter crowbar system

NASA Technical Reports Server (NTRS)

Daeges, J.; Bhanji, A.

1987-01-01

The effective protection of a klystron in a high-power transmitter requires the diversion of all stored energy in the protected circuit through an alternate low-impedance path, the crowbar, such that less than 1 joule of energy is dumped into the klystron during an internal arc. A scheme of adding a bypass inductor in the crowbar-protected circuit of the high-power transmitter was tested using computer simulations and actual measurements under a test load. Although this scheme has several benefits, including less power dissipation in the resistor, the tests show that the presence of inductance in the portion of the circuit to be protected severely hampers effective crowbar operation.

Effect of dehydration in the UV transmittance of "in vitro" corneas

NASA Astrophysics Data System (ADS)

Lincoln, Victor A. C.; Ventura, Liliane; Faria e Sousa, Sidney J.; Mello, Marcio M.

2012-03-01

In ophthalmology the research using "in vitro" corneas are an excellent model for studies of new ophthalmologic procedures, enabling the analysis of effectiveness, performance and even safety parameters of the procedure. In this work we studied four "in vitro" human corneas preserved in OPTISOL-GS, with initial average pachymetry of 542 microns and a post-mortem average of 6 days. The corneas were preserved in OPTISOL-GS and were washed with saline solution to remove the excess the preservative medium. The corneas were placed in a device aligned with an ultraviolet source of 3mw/cm2 and an optical fiber positioned after the device near the endothelium of the cornea. The UV transmittance spectra in the region of 360-370nm were captured by the emission of UV source for 3 seconds. These spectra were captured every 5 minutes in a total of 60 minutes, resulting in 13 spectra per cornea. The measured average initial UV transmittance was 73% and after 50 minutes of dehydration there was no significant difference in the corneal teansmittance properties. However, for the last 10 minutes we have observed a decrease in the UV transmittance of 4%, probably indicated by corneal dehydration and swelling (wrinkling of the cornea tissue. The final average pachymetry was 421 microns and the UV transmittance after the 60 minutes was 69%. Therefore we can suppose that the UV transmittance of corneas "in vitro" is invariant over a period of up to 60 minutes, even with the thickness decrease, since the material that absorbs in the UV region remains intact and only water loss occurs.

Polarization of Narrowband VLF Transmitter Signals as an Ionospheric Diagnostic

NASA Astrophysics Data System (ADS)

Gross, N. C.; Cohen, M. B.; Said, R. K.; Gołkowski, M.

2018-01-01

Very low frequency (VLF, 3-30 kHz) transmitter remote sensing has long been used as a simple yet useful diagnostic for the D region ionosphere (60-90 km). All it requires is a VLF radio receiver that records the amplitude and/or phase of a beacon signal as a function of time. During both ambient and disturbed conditions, the received signal can be compared to predictions from a theoretical model to infer ionospheric waveguide properties like electron density. Amplitude and phase have in most cases been analyzed each as individual data streams, often only the amplitude is used. Scattered field formulation combines amplitude and phase effectively, but does not address how to combine two magnetic field components. We present polarization ellipse analysis of VLF transmitter signals using two horizontal components of the magnetic field. The shape of the polarization ellipse is unchanged as the source phase varies, which circumvents a significant problem where VLF transmitters have an unknown source phase. A synchronized two-channel MSK demodulation algorithm is introduced to mitigate 90° ambiguity in the phase difference between the horizontal magnetic field components. Additionally, the synchronized demodulation improves phase measurements during low-SNR conditions. Using the polarization ellipse formulation, we take a new look at diurnal VLF transmitter variations, ambient conditions, and ionospheric disturbances from solar flares, lightning-ionospheric heating, and lightning-induced electron precipitation, and find differing signatures in the polarization ellipse.

Capacity Improvement of a Free Space Optical Satellite Uplink using Transmitter Power and Rate Adaptation

NASA Astrophysics Data System (ADS)

Gopal, Pooja; Jain, V. K.; Kar, Subrat

2017-12-01

Degradation due to atmospheric turbulence leads to significant outage in a free space optical satellite uplink with fixed transmitter parameters. If the channel state is known at the transmitter, then its parameters can be suitably changed, and there could be a considerable improvement in channel capacity. However, the extremely long link length of an Earth-to-Geostationary Earth Orbit (GEO) satellite link would render feedback of channel state from the receiver infeasible, before the channel changes. In this paper, a channel pre-estimation method at the transmitter is proposed, and the expression for capacity with transmitter power and rate adaptation is derived. The results are compared with that of the capacity with outage. It is observed that there can be an improvement by a factor of 1.66 in achievable average capacity per Hertz with the adaptive transmitter. Also, the outage probability is reduced from 18.02 % to almost 0.

An Exclusion Zone for Ca2+ Channels around Docked Vesicles Explains Release Control by Multiple Channels at a CNS Synapse

PubMed Central

Keller, Daniel; Babai, Norbert; Kochubey, Olexiy; Han, Yunyun; Markram, Henry; Schürmann, Felix; Schneggenburger, Ralf

2015-01-01

The spatial arrangement of Ca2+ channels and vesicles remains unknown for most CNS synapses, despite of the crucial importance of this geometrical parameter for the Ca2+ control of transmitter release. At a large model synapse, the calyx of Held, transmitter release is controlled by several Ca2+ channels in a "domain overlap" mode, at least in young animals. To study the geometrical constraints of Ca2+ channel placement in domain overlap control of release, we used stochastic MCell modelling, at active zones for which the position of docked vesicles was derived from electron microscopy (EM). We found that random placement of Ca2+ channels was unable to produce high slope values between release and presynaptic Ca2+ entry, a hallmark of domain overlap, and yielded excessively large release probabilities. The simple assumption that Ca2+ channels can be located anywhere at active zones, except below a critical distance of ~ 30 nm away from docked vesicles ("exclusion zone"), rescued high slope values and low release probabilities. Alternatively, high slope values can also be obtained by placing all Ca2+ channels into a single supercluster, which however results in significantly higher heterogeneity of release probabilities. We also show experimentally that high slope values, and the sensitivity to the slow Ca2+ chelator EGTA-AM, are maintained with developmental maturation of the calyx synapse. Taken together, domain overlap control of release represents a highly organized active zone architecture in which Ca2+ channels must obey a certain distance to docked vesicles. Furthermore, domain overlap can be employed by near-mature, fast-releasing synapses. PMID:25951120

Transmittance of transparent windows with non-absorbing cap-shaped droplets condensed on their backside

NASA Astrophysics Data System (ADS)

Zhu, Keyong; Huang, Yong; Pruvost, Jeremy; Legrand, Jack; Pilon, Laurent

2017-06-01

This study aims to quantify systematically the effect of non-absorbing cap-shaped droplets condensed on the backside of transparent windows on their directional-hemispherical transmittance and reflectance. Condensed water droplets have been blamed to reduce light transfer through windows in greenhouses, solar desalination plants, and photobioreactors. Here, the directional-hemispherical transmittance was predicted by Monte Carlo ray-tracing method. For the first time, both monodisperse and polydisperse droplets were considered, with contact angle between 0 and 180°, arranged either in an ordered hexagonal pattern or randomly distributed on the window backside with projected surface area coverage between 0 and 90%. The directional-hemispherical transmittance was found to be independent of the size and spatial distributions of the droplets. Instead, it depended on (i) the incident angle, (ii) the optical properties of the window and droplets, and on (iii) the droplet contact angle and (iv) projected surface area coverage. In fact, the directional-hemispherical transmittance decreased with increasing incident angle. Four optical regimes were identified in the normal-hemispherical transmittance. It was nearly constant for droplet contact angles either smaller than the critical angle θcr (predicted by Snell's law) for total internal reflection at the droplet/air interface or larger than 180°-θcr. However, between these critical contact angles, the normal-hemispherical transmittance decreased rapidly to reach a minimum at 90° and increased rapidly with increasing contact angles up to 180°-θcr. This was attributed to total internal reflection at the droplet/air interface which led to increasing reflectance. In addition, the normal-hemispherical transmittance increased slightly with increasing projected surface area coverage for contact angle was smaller than θcr. However, it decreased monotonously with increasing droplet projected surface area coverage for contact

Laser transmitter for space-based sodium lidar instrument

NASA Astrophysics Data System (ADS)

Yu, Anthony W.; Krainak, Michael A.; Janches, Diego; Konoplev, Oleg

2016-05-01

We are currently developing a laser transmitter to remotely measure Sodium (Na) by adapting existing lidar technology with space flight heritage. The developed instrumentation will serve as the core for the planning of a Heliophysics mission targeted to study the composition and dynamics of Earth's mesosphere based on a spaceborne lidar that will measure the mesospheric Na layer. We present performance results from our laser transmitter development effort with emphasis on wavelength tuning and power scaling of a diode-pumped Q-switched self-Raman c-cut Nd:YVO4 laser with intra-cavity frequency doubling that could produce multi-watt 589 nm wavelength output. We will review technologies that provide strong leverage for the sodium lidar laser system with strong heritage from past and current space flight missions.

Multi-transmitter multi-receiver null coupled systems for inductive detection and characterization of metallic objects

NASA Astrophysics Data System (ADS)

Smith, J. Torquil; Morrison, H. Frank; Doolittle, Lawrence R.; Tseng, Hung-Wen

2007-03-01

Equivalent dipole polarizabilities are a succinct way to summarize the inductive response of an isolated conductive body at distances greater than the scale of the body. Their estimation requires measurement of secondary magnetic fields due to currents induced in the body by time varying magnetic fields in at least three linearly independent (e.g., orthogonal) directions. Secondary fields due to an object are typically orders of magnitude smaller than the primary inducing fields near the primary field sources (transmitters). Receiver coils may be oriented orthogonal to primary fields from one or two transmitters, nulling their response to those fields, but simultaneously nulling to fields of additional transmitters is problematic. If transmitter coils are constructed symmetrically with respect to inversion in a point, their magnetic fields are symmetric with respect to that point. If receiver coils are operated in pairs symmetric with respect to inversion in the same point, then their differenced output is insensitive to the primary fields of any symmetrically constructed transmitters, allowing nulling to three (or more) transmitters. With a sufficient number of receivers pairs, object equivalent dipole polarizabilities can be estimated in situ from measurements at a single instrument sitting, eliminating effects of inaccurate instrument location on polarizability estimates. The method is illustrated with data from a multi-transmitter multi-receiver system with primary field nulling through differenced receiver pairs, interpreted in terms of principal equivalent dipole polarizabilities as a function of time.

A small long-life acoustic transmitter for studying the behavior of aquatic animals

DOE PAGES

Lu, J.; Deng, Z. D.; Li, H.; ...

2016-11-21

The lack of stronger acoustic signal, longer service life and smaller size from off-the-shelf transmitters has precluded intensive research for environmental monitoring of certain species using acoustic telemetry techniques. In this study we developed a small long-life acoustic transmitter with the length of approximately 24.2 mm, the diameter of approximately 5.0 mm, and the dry weight of approximately 0.72 g. The new transmitter can generate an acoustic signal at selectable source level between 159 and 163 dB re 1 µPa at 1 m. The new acoustic transmitter has an operation lifetime up to a year or longer at a pulsemore » rate interval of 15 seconds, and also has a signal detection range up to at least 500 meters that enhances detection probability in a quiet environment. Furthermore, the new technology makes long-term acoustic telemetry studies of small fish possible and is being deployed for long-term tracking of juvenile sturgeon.« less

A small long-life acoustic transmitter for studying the behavior of aquatic animals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, J.; Deng, Z. D.; Li, H.

The lack of stronger acoustic signal, longer service life and smaller size from off-the-shelf transmitters has precluded intensive research for environmental monitoring of certain species using acoustic telemetry techniques. In this study we developed a small long-life acoustic transmitter with the length of approximately 24.2 mm, the diameter of approximately 5.0 mm, and the dry weight of approximately 0.72 g. The new transmitter can generate an acoustic signal at selectable source level between 159 and 163 dB re 1 µPa at 1 m. The new acoustic transmitter has an operation lifetime up to a year or longer at a pulsemore » rate interval of 15 seconds, and also has a signal detection range up to at least 500 meters that enhances detection probability in a quiet environment. Furthermore, the new technology makes long-term acoustic telemetry studies of small fish possible and is being deployed for long-term tracking of juvenile sturgeon.« less

47 CFR 95.607 - CB transmitter modification.

Code of Federal Regulations, 2010 CFR

2010-10-01

... transmitting frequencies, increased modulation level, a different form of modulation, or increased TP (RF... modulating frequency, typically 0.1 seconds at maximum power) or peak envelope power (TP averaged during 1 RF cycle at the highest crest of the modulation envelope), as measured at the transmitter output antenna...

Molecular scaffold reorganization at the transmitter release site with vesicle exocytosis or botulinum toxin C1.

PubMed

Stanley, Elise F; Reese, Tom S; Wang, Gary Z

2003-10-01

Neurotransmitter release sites at the freeze-fractured frog neuromuscular junction are composed of inner and outer paired rows of large membrane particles, the putative calcium channels, anchored by the ribs of an underlying protein scaffold. We analysed the locations of the release site particles as a reflection of the scaffold structure, comparing particle distributions in secreting terminals with those where secretion was blocked with botulinum toxin A, which cleaves a small segment off SNAP-25, or botulinum toxin C1, which cleaves the cytoplasmic domain of syntaxin. In the idle terminal the inner and outer paired rows were located approximately 25 and approximately 44 nm, respectively, from the release site midline. However, adjacent to vesicular fusion sites both particle rows were displaced towards the midline by approximately 25%. The intervals between the particles along each row were examined by a nearest-neighbour approach. In control terminals the peak interval along the inner row was approximately 17 nm, consistent with previous reports and the spacing of the scaffold ribs. While the average distance between particles in the outer row was also approximately 17 nm, a detailed analysis revealed short 'linear clusters' with a approximately 14 nm interval. These clusters were enriched at vesicle fusion sites, suggesting an association with the docking sites, and were eliminated by botulinum C1, but not A. Our findings suggest, first, that the release site scaffold ribs undergo a predictable, and possibly active, shortening during exocytosis and, second, that at the vesicle docking site syntaxin plays a role in the cross-linking of the rib tips to form the vesicle docking sites.

78 FR 19314 - Agency Information Collection Activities; Submission for OMB Review; Comment Request: Transmittal...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-29

... for OMB Review; Comment Request: Transmittal of Unemployment Insurance Materials ACTION: Notice...) sponsored information collection request (ICR) titled, ``Transmittal of Unemployment Insurance Materials..., interpretations, court opinions, etc. In addition, the Unemployment Compensation for Federal Civilian Employees...

A satellite AOT derived from the ground sky transmittance measurements

NASA Astrophysics Data System (ADS)

Lim, H. S.; MatJafri, M. Z.; Abdullah, K.; Tan, K. C.; Wong, C. J.; Saleh, N. Mohd.

2008-10-01

The optical properties of aerosols such as smoke from burning vary due to aging processes and these particles reach larger sizes at high concentrations. The objectives of this study are to develop and evaluate an algorithm for estimating atmospheric optical thickness from Landsat TM image. This study measured the sky transmittance at the ground using a handheld spectroradiometer in a wide wavelength spectrum to retrieve atmospheric optical thickness. The in situ measurement of atmospheric transmittance data were collected simultaneously with the acquisition of remotely sensed satellite data. The digital numbers for the three visible bands corresponding to the in situ locations were extracted and then converted into reflectance values. The reflectance measured from the satellite was subtracted by the amount given by the surface reflectance to obtain the atmospheric reflectance. These atmospheric reflectance values were used for calibration of the AOT algorithm. This study developed an empirical method to estimate the AOT values from the sky transmittance values. Finally, a AOT map was generated using the proposed algorithm and colour-coded for visual interpretation.

Research on control technology of hardware parallelism for marine controlled source electromagnetic transmitter

NASA Astrophysics Data System (ADS)

Wang, Meng; Deng, Ming; Luo, Xianhu; Zhao, Qingxian; Chen, Kai; Jing, Jianen

2018-02-01

The marine controlled source electromagnetic (CSEM) method has been recognized as an effective exploration method of shallow hydrocarbons around the world. We developed our own underwater marine CSEM transmitter that consisted of many functional modules with various response times. We previously adopted a centralized software-control technology to design the transmitter circuit topological structure. That structure probably generated a control disorder or malfunction. These undesirable conditions could lead to repeated recovery and deployment of the transmitter, which not only consumed time but also affected data continuity and establishment of stable and continuous CSEM field. We developed an instrument design concept named ‘control technology of hardware parallelism’. In this design, a noteworthy innovation of our new technology is to solve the above-mentioned problems at the physical and fundamental levels. We used several self-contained control-units to simultaneously accomplish the predetermined functions of the transmitter. The new solution relies on two technologies: multi-core embedded technology and multi-channel parallel optical-fiber data transmission technology. The first technology depends on many independent microcontrollers. Every microcontroller is only used to achieve a customized function. The second one relies on several multiple optical-fiber transmission channels realized by a complex programmable logic device and two optical-fiber conversion devices, which are used to establish a communication link between the shipboard monitoring and control-unit and underwater transmitter. We have conducted some marine experiments to verify the reliability and stability of the new method. In particular, the new technology used in the transmitter system could help us obtain more useful measured data in a limited time, improve real-time efficiency, and support the establishment of a stable CSEM field.

Ionospheric Modification from Under-Dense Heating by High-Power HF Transmitter

DTIC Science & Technology

2011-03-03

Auroral Research Program ( HAARP ) is a HF transmitter, which delivers 0.36 to 3.6 GW effective isotropic radiated powers (F.IRP) for the radiation...dense heating, the EIRP of the HAARP heater can be increased significantly by increasing the heater frequency. With higher heater frequency, the loss...1304 local time) and on 13 April from 0812 to 0844 UTC (0012 to 0044 local time), using the HAARP transmitter facility at Gakona, AK, at full power

Combining Image Processing with Signal Processing to Improve Transmitter Geolocation Estimation

DTIC Science & Technology

2014-03-27

transmitter by searching a grid of possible transmitter locations within the image region. At each evaluated grid point, theoretical TDOA values are computed...requires converting the image to a grayscale intensity image. This allows efficient manipulation of data and ease of comparison among pixel values . The...cluster of redundant y values along the top edge of an ideal rectangle. The same is true for the bottom edge, as well as for the x values along the

Emergency Locator Transmitter (ELT) batteries guidance and recommendations

NASA Technical Reports Server (NTRS)

1984-01-01

Batteries for use with Emergency locator transmitters are discussed. Types of batteries, real-time activation considerations, encapsulation of cells in a battery pack, cold storage to extend shelf life, and general requirements are among the topics covered.

HyperART: non-invasive quantification of leaf traits using hyperspectral absorption-reflectance-transmittance imaging.

PubMed

Bergsträsser, Sergej; Fanourakis, Dimitrios; Schmittgen, Simone; Cendrero-Mateo, Maria Pilar; Jansen, Marcus; Scharr, Hanno; Rascher, Uwe

2015-01-01

Combined assessment of leaf reflectance and transmittance is currently limited to spot (point) measurements. This study introduces a tailor-made hyperspectral absorption-reflectance-transmittance imaging (HyperART) system, yielding a non-invasive determination of both reflectance and transmittance of the whole leaf. We addressed its applicability for analysing plant traits, i.e. assessing Cercospora beticola disease severity or leaf chlorophyll content. To test the accuracy of the obtained data, these were compared with reflectance and transmittance measurements of selected leaves acquired by the point spectroradiometer ASD FieldSpec, equipped with the FluoWat device. The working principle of the HyperART system relies on the upward redirection of transmitted and reflected light (range of 400 to 2500 nm) of a plant sample towards two line scanners. By using both the reflectance and transmittance image, an image of leaf absorption can be calculated. The comparison with the dynamically high-resolution ASD FieldSpec data showed good correlation, underlying the accuracy of the HyperART system. Our experiments showed that variation in both leaf chlorophyll content of four different crop species, due to different fertilization regimes during growth, and fungal symptoms on sugar beet leaves could be accurately estimated and monitored. The use of leaf reflectance and transmittance, as well as their sum (by which the non-absorbed radiation is calculated) obtained by the HyperART system gave considerably improved results in classification of Cercospora leaf spot disease and determination of chlorophyll content. The HyperART system offers the possibility for non-invasive and accurate mapping of leaf transmittance and absorption, significantly expanding the applicability of reflectance, based on mapping spectroscopy, in plant sciences. Therefore, the HyperART system may be readily employed for non-invasive determination of the spatio-temporal dynamics of various plant

Thermal Transmittance of Porous Hollow Clay Brick by Guarded Hot Box Method

NASA Astrophysics Data System (ADS)

Kim, Joonsoo

2018-03-01

The thermal property of a porous hollow clay brick was determined by measuring the thermal transmittance of the wall made of porous hollow clay bricks. Prior to the production of porous hollow clay bricks, nonporous and porous tiny clay bricks were prepared to determine the physico-mechanical properties by modifying the amount of wood flour and firing temperature. The bricks were produced by uniaxial pressing and then fired in an electric furnace. Their physico-mechanical properties were measured by water absorption, apparent porosity, bulk density, and compressive strength. The porous tiny clay bricks were produced with three types of wood flour: coarse wood flour (1-0.36 mm), medium-sized wood flour (0.36-0.15 mm), and fine wood flour (< 0.08 mm). The thermal transmittance of porous hollow clay bricks was determined through the guarded hot box method, which measures the wall made of porous hollow clay bricks and nonporous cement bricks. The two walls had a thermal transmittance of 1.42 and 2.72 W\\cdot m^{-2}\\cdot K^{-1}, respectively. The difference in thermal transmittance was due to the pores created with fine wood flour (< 0.08 mm) as a pore-forming agent.

Olfactory bulb short axon cell release of GABA and dopamine produces a temporally biphasic inhibition-excitation response in external tufted cells

PubMed Central

Liu, Shaolin; Plachez, Celine; Shao, Zuoyi; Puche, Adam; Shipley, Michael T.

2013-01-01

Evidence for co-expression of two or more classic neurotransmitters in neurons has increased but less is known about co-transmission. Ventral tegmental area (VTA) neurons, co-release dopamine (DA), the excitatory transmitter glutamate and the inhibitory transmitter GABA onto target cells in the striatum. Olfactory bulb (OB) short axon cells (SACs) form interglomerular connections and co-express markers for dopamine (DA) and GABA. Using an optogenetic approach we provide evidence that mouse OB SACs release both GABA and DA onto external tufted cells (ETCs) in other glomeruli. Optical activation of channelrhodopsin specifically expressed in DAergic SACs produced a GABAA receptor-mediated monosynaptic inhibitory response followed by DA-D1-like receptor-mediated excitatory response in ETCs. The GABAA receptor-mediated hyperpolarization activates Ih current in ETCs; synaptically released DA increases Ih, which enhances post-inhibitory rebound spiking. Thus, the opposing actions of synaptically released GABA and DA are functionally integrated by Ih to generate an inhibition-to-excitation “switch” in ETCs. Consistent with the established role of Ih in ETC burst firing, we show that endogenous DA release increases ETC spontaneous bursting frequency. ETCs transmit sensory signals to mitral/tufted output neurons and drive intraglomerular inhibition to shape glomerulus output to downstream olfactory networks. GABA and DA co-transmission from SACs to ETCs may play a key role in regulating output coding across the glomerular array. PMID:23407950

Age-related changes in spectral transmittance of the human crystalline lens in situ.

PubMed

Sakanishi, Yoshihito; Awano, Masakazu; Mizota, Atsushi; Tanaka, Minoru; Murakami, Akira; Ohnuma, Kazuhiko

2012-01-01

It was the aim of this study to measure spectral transmission of the human crystalline lens in situ. The crystalline lens was illuminated by one of four light-emitting diodes of different colors. The relative spectral transmittance of the human crystalline lens was measured with the Purkinje-Sanson mirror images over a wide range of ages. The study evaluated 36 crystalline lenses of 28 subjects aged 21-76 years. There was a significant correlation between the age and spectral transmittance for blue light. Spectral transmittance of the crystalline lens in situ could be measured with Purkinje-Sanson mirror images. Copyright © 2012 S. Karger AG, Basel.

Abdominally implanted transmitters with percutaneous antennas affect the dive performance of Common Eiders

USGS Publications Warehouse

Powell, Abby N.; Latty, Christopher J.; Hollmén, Tuula E.; Petersen, Margaret R.; Andrews, Russel D.

2010-01-01

Implanted transmitters have become an important tool for studying the ecology of sea ducks, but their effects remain largely undocumented. To address this, we assessed how abdominally implanted transmitters with percutaneous antennas affect the vertical dive speeds, stroke frequencies, bottom time, and dive duration of captive Common Eiders (Somateria mollissima). To establish baselines, we recorded video of six birds diving 4.9 m prior to surgery, implanted them with 38- to 47-g platform transmitter terminals, and then recorded their diving for 3.5 months after surgery to determine effects. Descent speeds were 16–25% slower and ascent speeds were 17–44% slower after surgery, and both remained below baseline at the end of the study. Dive durations were longer than baseline until day 22. On most days between 15 and 107 days after surgery, foot-stroke frequencies of birds foraging on the bottom were slower. Foot- and wing-stroke frequencies during descent and bottom time did not differ across the time series. If birds that rely on benthic invertebrates for sustenance dive slower and stay submerged longer after being implanted with a satellite transmitter, their foraging energetics may be affected. Researchers considering use of implanted transmitters with percutaneous antennas should be mindful of these effects and the possibility of concomitant alterations in diving behavior, foraging success, and migratory behavior compared to those of unmarked conspecifics.

Subcutaneous anchor attachment increases retention of radio transmitters on Xantus' and marbled murrelets

USGS Publications Warehouse

Newman, Scott H.; Takekawa, John Y.; Whitworth, Darrell L.; Burkett, Esther E.

1999-01-01

We modified a subcutaneous anchor attachment and achieved transmitter reten- tion times that exceeded those reported previously for other attachments used on alcids. Traditional suture and epoxy attachment methods were used on Xantus' Murrelets in 1995 and 1996, while the modified attachment was used for Xantus' Murrelets in 1996 and 1997 and Marbled Murrelets in 1997. Modifications included use of an inhalant anesthetic, placing the anchor in a more cranial position on the back, application of marine epoxy, and place- ment of a single subcutaneous non-absorbable suture at the caudal end of the radio to hold the radio in place initially. We located 22 of 56 (39%) Xantus' Murrelets radio-marked using suture and epoxy during aerial surveys in 1995 and 1996. Of birds radio-marked using the subcutaneous anchor attachment, we located 92 of 113 (81%) Xantus' Murrelets marked in 1996 and 1997 and all 28 (100%) Marbled Murrelets marked in 1997 during aerial surveys. The maximum confirmed duration for the subcutaneous anchor transmitter attachment was 51 d for Xantus' Murrelets and 78 d for Marbled Murrelets versus 41 d for the suture and epoxy attachment used on Xantus' Murrelets. Recapture rates of radio-marked Xantus' Mur- relets were similar to recapture rates of unmarked Xantus' Murrelets. Our post-release ob- servations indicated negligible short-term physical effects from the attachment procedure, while telemetry data and examination of recaptured murrelets indicated no evidence of infection or other long-term physical effects. Breeding behavior of some murrelets was not disrupted; however, further evaluation of potential effects of this attachment technique on breeding and behavior is needed.

Design and calculation of low infrared transmittance and low emissivity coatings for heat radiative applications

NASA Astrophysics Data System (ADS)

Wang, Guang-Hai; Zhang, Yue; Zhang, Da-Hai; Fan, Jin-Peng

2012-02-01

The infrared transmittance and emissivity of heat-insulating coatings pigmented with various structural particles were studied using Kubelka-Munk theory and Mie theory. The primary design purpose was to obtain the low transmittance and low emissivity coatings to reduce the heat transfer by thermal radiation for high-temperature applications. In the case of silica coating layers constituted with various structural titania particles (solid, hollow, and core-shell spherical), the dependence of transmittance and emissivity of the coating layer on the particle structure and the layer thickness was investigated and optimized. The results indicate that the coating pigmented with core-shell titania particles exhibits a lower infrared transmittance and a lower emissivity value than that with other structural particles and is suitable to radiative heat-insulating applications.

Activation of K+ channels by lanthanum contributes to the block of transmitter release in chick and rat sympathetic neurons.

PubMed

Przywara, D A; Bhave, S V; Bhave, A; Chowdhury, P S; Wakade, T D; Wakade, A R

1992-01-01

We studied the effects of lanthanum (La3+) on the release of 3H-norepinephrine (3H-NE), intracellular Ca2+ concentration, and voltage clamped Ca2+ and K+ currents in cultured sympathetic neurons. La3+ (0.1 to 10 microM) produced concentration-dependent inhibition of depolarization induced Ca2+ influx and 3H-NE release. La3+ was more potent and more efficacious in blocking 3H-NE release than the Ca(2+)-channel blockers cadmium and verapamil, which never blocked more than 70% of the release. At 3 microM, La3+ produced a complete block of the electrically stimulated rise in intracellular free Ca2+ ([Ca2+]i) in the cell body and the growth cone. The stimulation-evoked release of 3H-NE was also completely blocked by 3 microM La3+. However, 3 microM La3+ produced only a partial block of voltage clamped Ca2+ current (ICa). Following La3+ (10 microM) treatment 3H-NE release could be evoked by high K+ stimulation of neurons which were refractory to electrical stimulation. La3+ (1 microM) increased the hyperpolarization activated, 4-aminopyridine (4-AP) sensitive, transient K+ current (IA) with little effect on the late outward current elicited from depolarized holding potentials. We conclude that the effective block of electrically stimulated 3H-NE release is a result of the unique ability of La3+ to activate a stabilizing, outward K+ current at the same concentration that it blocks inward Ca2+ current.

NOVEL TECHNIQUE OF POWER CONTROL IN MAGNETRON TRANSMITTERS FOR INTENSE ACCELERATORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kazakevich, G.; Johnson, R.; Neubauer, M.

A novel concept of a high-power magnetron transmitter allowing dynamic phase and power control at the frequency of locking signal is proposed. The transmitter compensating parasitic phase and amplitude modulations inherent in Superconducting RF (SRF) cavities within closed feedback loops is intended for powering of the intensity-frontier superconducting accelerators. The con- cept uses magnetrons driven by a sufficient resonant (in- jection-locking) signal and fed by the voltage which can be below the threshold of self-excitation. This provides an extended range of power control in a single magnetron at highest efficiency minimizing the cost of RF power unit and the operationmore » cost. Proof-of-principle of the proposed concept demonstrated in pulsed and CW regimes with 2.45 GHz, 1kW magnetrons is discussed here. A conceptual scheme of the high-power transmitter allowing the dynamic wide-band phase and y power controls is presented and discussed.« less

Transmittance of semitransparent windows with absorbing cap-shaped droplets condensed on their backside

NASA Astrophysics Data System (ADS)

Zhu, Keyong; Pilon, Laurent

2017-11-01

This study aims to investigate systematically light transfer through semitransparent windows with absorbing cap-shaped droplets condensed on their backside as encountered in greenhouses, solar desalination plants, photobioreactors and covered raceway ponds. The Monte Carlo ray-tracing method was used to predict the normal-hemispherical transmittance, reflectance, and normal absorptance accounting for reflection and refraction at the air/droplet, droplet/window, and window/air interfaces and absorption in both the droplets and the window. The droplets were monodisperse or polydisperse and arranged either in an ordered hexagonal pattern or randomly distributed on the backside with droplet contact angle θc ranging between 0 and 180° The normal-hemispherical transmittance was found to be independent of the spatial distribution of droplets. However, it decreased with increasing droplet diameter and polydispersity. The normal-hemispherical transmittance featured four distinct optical regimes for semitransparent window supporting nonabsorbing droplets. These optical regimes were defined based on contact angle and critical angle for internal reflection at the droplet/air interface. However, for strongly absorbing droplets, the normal-hemispherical transmittance (i) decreased monotonously with increasing contact angle for θc <90° and (ii) remained constant and independent of droplet absorption index kd, droplet mean diameter dm, and contact angle θc for θc ≥ 90° Analytical expressions for the normal-hemispherical transmittance were provided in the asymptotic cases when (1) the window was absorbing but the droplets were nonabsorbing with any contact angles θc, and (2) the droplets were strongly absorbing with contact angle θc >90° Finally, the spectral normal-hemispherical transmittance of a 3 mm-thick glass window supporting condensed water droplets for wavelength between 0.4 and 5 μm was predicted and discussed in light of the earlier parametric study and

Simultaneous identification of optical constants and PSD of spherical particles by multi-wavelength scattering-transmittance measurement

NASA Astrophysics Data System (ADS)

Zhang, Jun-You; Qi, Hong; Ren, Ya-Tao; Ruan, Li-Ming

2018-04-01

An accurate and stable identification technique is developed to retrieve the optical constants and particle size distributions (PSDs) of particle system simultaneously from the multi-wavelength scattering-transmittance signals by using the improved quantum particle swarm optimization algorithm. The Mie theory are selected to calculate the directional laser intensity scattered by particles and the spectral collimated transmittance. The sensitivity and objective function distribution analysis were conducted to evaluate the mathematical properties (i.e. ill-posedness and multimodality) of the inverse problems under three different optical signals combinations (i.e. the single-wavelength multi-angle light scattering signal, the single-wavelength multi-angle light scattering and spectral transmittance signal, and the multi-angle light scattering and spectral transmittance signal). It was found the best global convergence performance can be obtained by using the multi-wavelength scattering-transmittance signals. Meanwhile, the present technique have been tested under different Gaussian measurement noise to prove its feasibility in a large solution space. All the results show that the inverse technique by using multi-wavelength scattering-transmittance signals is effective and suitable for retrieving the optical complex refractive indices and PSD of particle system simultaneously.

An unobtrusive liquid sensor utilizing a micromilled RF spark gap transmitter and resonant cavity

NASA Astrophysics Data System (ADS)

Berry, H.; Wilson, C.

2009-09-01

This paper reports on a new dielectric liquid sensor that utilizes an RF sparkgap transmitter coupled with an aluminum microwave resonant cavity. The transmitter is a micromilled polymer transmitter housing with patterned copper electrodes that generate micro-arcs. This transmitter which operates outside the measured liquid generates a directed ultrawideband signal which is received by the aluminum waveguide. Absorption resonances in the microwave cavity, measured with a spectrum analyzer are a function of the liquids' dielectric constant at lower frequencies, as well as from molecular vibrations/rotations at higher frequencies. In many chemical manufacturing processes, liquids being manufactured are removed, tested in a lab, and then disposed of, or else they will contaminate the full batch. In beer brewing, for instance, samples are removed, density tested for alcohol content, then disposed of. Using this sensor, the chemical process could be continuously monitored by a computerized system without risk of contamination.

Ultrasonic imaging using optoelectronic transmitters.

PubMed

Emery, C D; Casey, H C; Smith, S W

1998-04-01

Conventional ultrasound scanners utilize electronic transmitters and receivers at the scanner with a separate coaxial cable connected to each transducer element in the handle. The number of transducer elements determines the size and weight of the transducer cable assembly that connects the imaging array to the scanner. 2-D arrays that allow new imaging modalities to be introduced significantly increase the channel count making the transducer cable assembly more difficult to handle. Therefore, reducing the size and increasing the flexibility of the transducer cable assembly is a concern. Fiber optics can be used to transmit signals optically and has distinct advantages over standard coaxial cable to increase flexibility and decrease the weight of the transducer cable for larger channel numbers. The use of fiber optics to connect the array and the scanner entails the use of optoelectronics such as detectors and laser diodes to send and receive signals. In transmit, optoelectronics would have to be designed to produce high-voltage wide-bandwidth pulses across the transducer element. In this paper, we describe a 48 channel ultrasound system having 16 optoelectronic transmitters and 32 conventional electronic receivers. We investigated both silicon avalanche photodiodes (APD's) and GaAs lateral photoconductive semiconductor switches (PCSS's) for producing the transmit pulses. A Siemens SI-1200 scanner and a 2.25 MHz linear array were used to compare the optoelectronic system to a conventional electronic transmit system. Transmit signal results and images in tissue mimicking of cysts and tumors are provided for comparison.

Microscopically crumpled indium-tin-oxide thin films as compliant electrodes with tunable transmittance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ong, Hui-Yng; School of Engineering, Nanyang Polytechnic, Singapore 569830; Shrestha, Milan

2015-09-28

Indium-tin-oxide (ITO) thin films are perceived to be stiff and brittle. This letter reports that crumpled ITO thin films on adhesive poly-acrylate dielectric elastomer can make compliant electrodes, sustaining compression of up to 25% × 25% equi-biaxial strain and unfolding. Its optical transmittance reduces with crumpling, but restored with unfolding. A dielectric elastomer actuator (DEA) using the 14.2% × 14.2% initially crumpled ITO thin-film electrodes is electrically activated to produce a 37% areal strain. Such electric unfolding turns the translucent DEA to be transparent, with transmittance increased from 39.14% to 52.08%. This transmittance tunability promises to make a low-cost smart privacy window.

47 CFR 95.667 - CB transmitter power.

Code of Federal Regulations, 2013 CFR

2013-10-01

... transmitter power. The dissipation rating of all the semiconductors or electron tubes which supply RF power to... semiconductor. These values may be temperature de-rated by no more than 50 °C. For an electron tube, the... the manufacturer of the electron tube. [53 FR 36789, Sept. 22, 1988. Redesignated at 61 FR 28769, June...

47 CFR 95.667 - CB transmitter power.

Code of Federal Regulations, 2012 CFR

2012-10-01

... transmitter power. The dissipation rating of all the semiconductors or electron tubes which supply RF power to... semiconductor. These values may be temperature de-rated by no more than 50 °C. For an electron tube, the... the manufacturer of the electron tube. [53 FR 36789, Sept. 22, 1988. Redesignated at 61 FR 28769, June...

47 CFR 95.667 - CB transmitter power.

Code of Federal Regulations, 2014 CFR

2014-10-01

... transmitter power. The dissipation rating of all the semiconductors or electron tubes which supply RF power to... semiconductor. These values may be temperature de-rated by no more than 50 °C. For an electron tube, the... the manufacturer of the electron tube. [53 FR 36789, Sept. 22, 1988. Redesignated at 61 FR 28769, June...

Implementation and validation of a CubeSat laser transmitter

NASA Astrophysics Data System (ADS)

Kingsbury, R. W.; Caplan, D. O.; Cahoy, K. L.

2016-03-01

The paper presents implementation and validation results for a CubeSat-scale laser transmitter. The master oscillator power amplifier (MOPA) design produces a 1550 nm, 200mW average power optical signal through the use of a directly modulated laser diode and a commercial fiber amplifier. The prototype design produces high-fidelity M-ary pulse position modulated (PPM) waveforms (M=8 to 128), targeting data rates > 10 Mbit/s while meeting a constraining 8W power allocation. We also present the implementation of an avalanche photodiode (APD) receiver with measured transmitter-to-receiver performance within 3 dB of theory. Via loopback, the compact receiver design can provide built-in self-test and calibration capabilities, and supports incremental on-orbit testing of the design.

Scattering, absorption and transmittance of experimental graphene dental nanocomposites

NASA Astrophysics Data System (ADS)

Pérez, María. M.; Salas, Marianne; Moldovan, Marionara; Dudea, Diana; Yebra, Ana; Ghinea, Razvan

2017-08-01

Optical properties of experimental graphene dental nanocomposites were studied. Spectral reflectance was measured and S and K coefficients as well as transmittance of samples were calculated using Kubelka-Munk's equations. The spectral behavior of S, K and T experimental graphene exhibited different trends compared with the commercial nanocomposites and they were statistically different. Experimental nanocomposites show higher scattering and lower transmittance when compared with commercial nanocomposite, probably, due to the shape, type and size of the filler. K for short wavelength of the pre-polymerized experimental nancomposites was very low. According to our results, hidroxypatite with graphene oxide used in dental nanocomposites needs to be improved to reproduce esthetic properties of natural dental tissues and to have potentially clinical applications.

Presynaptic Membrane Receptors Modulate ACh Release, Axonal Competition and Synapse Elimination during Neuromuscular Junction Development.

PubMed

Tomàs, Josep; Garcia, Neus; Lanuza, Maria A; Santafé, Manel M; Tomàs, Marta; Nadal, Laura; Hurtado, Erica; Simó, Anna; Cilleros, Víctor

2017-01-01

During the histogenesis of the nervous system a lush production of neurons, which establish an excessive number of synapses, is followed by a drop in both neurons and synaptic contacts as maturation proceeds. Hebbian competition between axons with different activities leads to the loss of roughly half of the neurons initially produced so connectivity is refined and specificity gained. The skeletal muscle fibers in the newborn neuromuscular junction (NMJ) are polyinnervated but by the end of the competition, 2 weeks later, the NMJ are innervated by only one axon. This peripheral synapse has long been used as a convenient model for synapse development. In the last few years, we have studied transmitter release and the local involvement of the presynaptic muscarinic acetylcholine autoreceptors (mAChR), adenosine autoreceptors (AR) and trophic factor receptors (TFR, for neurotrophins and trophic cytokines) during the development of NMJ and in the adult. This review article brings together previously published data and proposes a molecular background for developmental axonal competition and loss. At the end of the first week postnatal, these receptors modulate transmitter release in the various nerve terminals on polyinnervated NMJ and contribute to axonal competition and synapse elimination.

Effects of surgically and gastrically implanted radio transmitters on growth and feeding behavior of juvenile chinook salmon

USGS Publications Warehouse

Adams, N.S.; Rondorf, D.W.; Evans, S.D.; Kelly, J.E.

1997-01-01

We examined the effects of surgically and gastrically implanted radio transmitters (representing 2.3-5.5% of body weight) on the growth and feeding behavior of 192 juvenile chinook salmon Oncorhynchus tshawytscha (114-159 mm in fork length). Throughout the 54-d study, the 48 fish with transmitters in their stomachs (gastric fish) consistently grew more slowly than fish with surgically implanted transmitters (surgery fish), fish with surgery but no implanted transmitter (sham-surgery fish), or fish exposed only to handling (control fish). Growth rates of surgery fish were also slightly impaired at day 21, but by day 54 they were growing at rates comparable with those of control fish. Despite differences in growth, overall health was similar among all test fish. However, movement of the transmitter antenna caused abrasions at the corner of the mouth in all gastric fish, whereas only 22% of the surgery fish had inflammation around the antenna exit wound. Feeding activity was similar among groups, but gastric fish exhibited a coughing behavior and appeared to have difficulty retaining swallowed food. Because growth and feeding behavior were less affected by the presence of surgically implanted transmitters than by gastric implants, we recommend surgically implanting transmitters for biotelemetry studies of juvenile chinook salmon between 114 and 159 mm fork length.

Variability in the vacuum-ultraviolet transmittance of magnesium fluoride windows. [for Space Telescope Imaging Spectrograph

NASA Technical Reports Server (NTRS)

Herzig, Howard; Fleetwood, Charles M., Jr.; Toft, Albert R.

1992-01-01

Sample window materials tested during the development of a domed magnesium fluoride detector window for the Hubble Space Telescope's Imaging Spectrograph are noted to exhibit wide variability in VUV transmittance; a test program was accordingly instituted to maximize a prototype domed window's transmittance. It is found that VUV transmittance can be maximized if the boule from which the window is fashioned is sufficiently large to allow such a component to be cut from the purest available portion of the boule.

Simultaneously Load and Extended Release of Betamethasone and Ciprofloxacin from Vitamin E-Loaded Silicone-Based Soft Contact Lenses.

PubMed

Rad, Maryam Shayani; Mohajeri, Seyed Ahmad

2016-09-01

The purpose of the present study was to evaluate the efficacy of commercial soft contact lenses, loaded with vitamin E, as ocular drug delivery systems for simultaneous loading and release of ciprofloxacin (Cipro) and betamethasone (BMZ) in artificial tears. In this study, we applied vitamin E as a barrier to increase BMZ-Cipro loading into three commercial silicone-based soft contact lenses and control their simultaneous release into the artificial lachrymal fluid. Two different concentrations of vitamin E solution (0.1 and 0.2 g/ml) were used, and various parameters including changes in lens diameter, water content, ultraviolet-visible light (UV-Vis) transmittance, drug-binding properties, and drug release profile were investigated. The obtained results indicated that vitamin E significantly reduced the swelling properties of contact lenses in aqueous media, while it enhanced the lens diameter in both dry and hydrated states. Vitamin E had no significant effects on visible transmittance, while it blocked UV radiation, which could be harmful for the eye surface. Our findings revealed that vitamin E improved the simultaneous loading amount of BMZ-Cipro into soft contact lenses. Additionally, BMZ and Cipro release rates significantly reduced after using vitamin E as a hydrophobic diffusion barrier. After soaking the lenses in 0.1 and 0.2 g/ml of vitamin E solution, BMZ release time increased by 28.8-81.6 and 182.4-201 folds, respectively. Moreover, Cipro release time increased by 12-18 and 1152-2313 folds, respectively. The results of the present study indicated the efficacy of vitamin E as a diffusion barrier in developing a controlled drug delivery system for the simultaneous loading of BMZ and Cipro and sustaining their release from soft contact lenses.

How-To-Do-It: Goof-Proof Biotelemetry Transmitter Construction.

ERIC Educational Resources Information Center

Ford, Brian K.; Van Scheik, William J.

1988-01-01

Presents a method of constructing short range transmitters suitable for sensing the temperature in eggs, nest cavities or other applications. Provides a list of materials, circuit diagram, and assembly instructions. (CW)

12. Hard HF transmitter antenna, view toward west. Lyon ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. Hard HF transmitter antenna, view toward west. Lyon - Whiteman Air Force Base, Oscar O-1 Minuteman Missile Alert Facility, Southeast corner of Twelfth & Vendenberg Avenues, Knob Noster, Johnson County, MO

A beaded collar for dual micro GPS/VHF transmitter attachment to nutria

USGS Publications Warehouse

Haramis, G.M.; White, T.S.

2011-01-01

We report on the development of an approximately 85-g beaded collar for dual micro GPS/VHF transmitter attachment to semi-aquatic nutria (Myocastor coypus). Prototype collars were tested on captive nutria and refined during field trials. Central to the design was novel use of the VHF transmitter antenna as a collar. A circular collar was formed by passing the 44-cm antenna cable through a pre-made hole in the transmitter, leaving an approximately 16-cm upright antenna. GPS units were mounted separately via a hole in the base of each unit. For good satellite contact, GPS units (28 g) were maintained at the nape of the neck by counterbalance of the heavier VHF transmitters (50 g) positioned under the neck. To reduce friction, we lined the collar with alternate-sized plastic and, later, more durable nylon beads. The final collar configuration was worn for approximately 1 month deployments with only minor neck abrasion; one collar was worn successfully for 5 months. Foot entanglement remained the greatest risk of injury from the collar. By fitting collars tightly, we reduced the incidence of foot entanglement to 2 of 33 deployments (6%). Successful GPS tracks were acquired on 29 of 33 deployments (88%).

Optical fiber ultrasound transmitter with electrospun carbon nanotube-polymer composite

NASA Astrophysics Data System (ADS)

Poduval, Radhika K.; Noimark, Sacha; Colchester, Richard J.; Macdonald, Thomas J.; Parkin, Ivan P.; Desjardins, Adrien E.; Papakonstantinou, Ioannis

2017-05-01

All-optical ultrasound transducers are promising for imaging applications in minimally invasive surgery. In these devices, ultrasound is transmitted and received through laser modulation, and they can be readily miniaturized using optical fibers for light delivery. Here, we report optical ultrasound transmitters fabricated by electrospinning an absorbing polymer composite directly onto the end-face of optical fibers. The composite coating consisting of an aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) in polyvinyl alcohol was directly electrospun onto the cleaved surface of a multimode optical fiber and subsequently dip-coated with polydimethylsiloxane (PDMS). This formed a uniform nanofibrous absorbing mesh over the optical fiber end-face wherein the constituent MWCNTs were aligned preferentially along individual nanofibers. Infiltration of the PDMS through this nanofibrous mesh onto the underlying substrate was observed and the resulting composites exhibited high optical absorption (>97%). Thickness control from 2.3 μm to 41.4 μm was obtained by varying the electrospinning time. Under laser excitation with 11 μJ pulse energy, ultrasound pressures of 1.59 MPa were achieved at 1.5 mm from the coatings. On comparing the electrospun ultrasound transmitters with a dip-coated reference fabricated using the same constituent materials and possessing identical optical absorption, a five-fold increase in the generated pressure and wider bandwidth was observed. The electrospun transmitters exhibited high optical absorption, good elastomer infiltration, and ultrasound generation capability in the range of pressures used for clinical pulse-echo imaging. All-optical ultrasound probes with such transmitters fabricated by electrospinning could be well-suited for incorporation into catheters and needles for diagnostics and therapeutic applications.

Heating of the nighttime D region by very low frequency transmitters

NASA Astrophysics Data System (ADS)

Rodriguez, Juan V.; Inan, Umran S.; Bell, Timothy F.

1994-12-01

VLF signals propagating in the Earth-ionosphere waveguide are used to probe the heated nighttime D region over three U.S. Navy very low frequency (VLF,3-30 kHz) transmitters. Ionospheric cooling and heating are observed when a transmitter turns off and on in the course of normal operations. Heating by the 24.0-kHz NAA transmitter in Cutler, Maine, (1000 kW radiated power) was observed by this method in 41 of 52 off/on episodes during December 1992, increasing the amplitude and retarding the phase of the 21.4-kHz NSS probe wave propagating from Annapolis, Maryland, to Gander, Newfoundland, by as much as 0.84 dB and 5.3 deg, respectively. In 6 of these 41 episodes, the amplitude of the 28.5-kHz NAU probe wave propagating from Puerto Rico to Gander was also perturbed by as much as 0.29 dB. The latter observations were unexpected due to the greater than 770 km distance between NAA and the NAU-Gander great circle path. Heating by the NSS (21.4 kHz, 265 kW) and NLK (24.8 kHz, 850 kW) transmitters was observed serendipitously in data from earlier measurements of the amplitudes of VLF signals propagating in the Earth-ionosphere waveguide. A three-dimensional model of wave absorption and electron heating in a magnetized, weakly ionized plasma is used to calculate the extent nad shape of the collision frequency (i.e., electron temperature) enhancement above a VLF transmitter. The enhancements are annular, with a geomagnetic north-south asymmetry and a radius at the outer half-maximum of the collision frequency enhancement of about 150 km. Heating by the NAA transmitter is predicted to increase the nighttime D region electron temperature by as much as a factor of 3. The calculated changes in the D region conductivity are used in a three-dimensional model of propagation in the Earth-ionosphere wavelength to predict the effect of the heated patch on a subionospheric VLF probe wave. The range of predicted scattered field amplitudes is in general consistent with the observed

Heating of the nighttime D region by very low frequency transmitters

NASA Technical Reports Server (NTRS)

Rodriguez, Juan V.; Inan, Umran S.; Bell, Timothy F.

1994-01-01

VLF signals propagating in the Earth-ionosphere waveguide are used to probe the heated nighttime D region over three U.S. Navy very low frequency (VLF,3-30 kHz) transmitters. Ionospheric cooling and heating are observed when a transmitter turns off and on in the course of normal operations. Heating by the 24.0-kHz NAA transmitter in Cutler, Maine, (1000 kW radiated power) was observed by this method in 41 of 52 off/on episodes during December 1992, increasing the amplitude and retarding the phase of the 21.4-kHz NSS probe wave propagating from Annapolis, Maryland, to Gander, Newfoundland, by as much as 0.84 dB and 5.3 deg, respectively. In 6 of these 41 episodes, the amplitude of the 28.5-kHz NAU probe wave propagating from Puerto Rico to Gander was also perturbed by as much as 0.29 dB. The latter observations were unexpected due to the greater than 770 km distance between NAA and the NAU-Gander great circle path. Heating by the NSS (21.4 kHz, 265 kW) and NLK (24.8 kHz, 850 kW) transmitters was observed serendipitously in data from earlier measurements of the amplitudes of VLF signals propagating in the Earth-ionosphere waveguide. A three-dimensional model of wave absorption and electron heating in a magnetized, weakly ionized plasma is used to calculate the extent nad shape of the collision frequency (i.e., electron temperature) enhancement above a VLF transmitter. The enhancements are annular, with a geomagnetic north-south asymmetry and a radius at the outer half-maximum of the collision frequency enhancement of about 150 km. Heating by the NAA transmitter is predicted to increase the nighttime D region electron temperature by as much as a factor of 3. The calculated changes in the D region conductivity are used in a three-dimensional model of propagation in the Earth-ionosphere wavelength to predict the effect of the heated patch on a subionospheric VLF probe wave. The range of predicted scattered field amplitudes is in general consistent with the observed

Methods of Phase and Power Control in Magnetron Transmitters for Superconducting Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kazadevich, G.; Johnson, R.; Neubauer, M.

Various methods of phase and power control in magnetron RF sources of superconducting accelerators intended for ADS-class projects were recently developed and studied with conventional 2.45 GHz, 1 kW, CW magnetrons operating in pulsed and CW regimes. Magnetron transmitters excited by a resonant (injection-locking) phasemodulated signal can provide phase and power control with the rates required for precise stabilization of phase and amplitude of the accelerating field in Superconducting RF (SRF) cavities of the intensity-frontier accelerators. An innovative technique that can significantly increase the magnetron transmitter efficiency at the widerange power control required for superconducting accelerators was developed and verifiedmore » with the 2.45 GHz magnetrons operating in CW and pulsed regimes. High efficiency magnetron transmitters of this type can significantly reduce the capital and operation costs of the ADSclass accelerator projects.« less

47 CFR 95.639 - Maximum transmitter power.

Code of Federal Regulations, 2012 CFR

2012-10-01

... condition of modulation, shall exceed: (1) 50 W Carrier power (average TP during one unmodulated RF cycle... output power authorized for LPRS stations is 100 mW. (f) In the MedRadio Service: (1) For transmitters..., the peak EIRP over the frequency bands of operation shall not exceed the lesser of 1 mW or 10 log B—7...

48 CFR 14.203-1 - Transmittal to prospective bidders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... CONTRACTING METHODS AND CONTRACT TYPES SEALED BIDDING Solicitation of Bids 14.203-1 Transmittal to prospective... outside the United States shall be sent by electronic data interchange or air mail if security...

A sub-nW 2.4 GHz Transmitter for Low Data-Rate Sensing Applications

PubMed Central

Mercier, Patrick P.; Bandyopadhyay, Saurav; Lysaght, Andrew C.; Stankovic, Konstantina M.; Chandrakasan, Anantha P.

2015-01-01

This paper presents the design of a narrowband transmitter and antenna system that achieves an average power consumption of 78 pW when operating at a duty-cycled data rate of 1 bps. Fabricated in a 0.18 µm CMOS process, the transmitter employs a direct-RF power oscillator topology where a loop antenna acts as a both a radiative and resonant element. The low-complexity single-stage architecture, in combination with aggressive power gating techniques and sizing optimizations, limited the standby power of the transmitter to only 39.7 pW at 0.8 V. Supporting both OOK and FSK modulations at 2.4 GHz, the transmitter consumed as low as 38 pJ/bit at an active-mode data rate of 5 Mbps. The loop antenna and integrated diodes were also used as part of a wireless power transfer receiver in order to kick-start the system power supply during energy harvesting operation. PMID:26246641

Comparison of light transmittance in different thicknesses of zirconia under various light curing units

PubMed Central

Egilmez, Ferhan; Ergun, Gulfem

2012-01-01

PURPOSE The objective of this study was to compare the light transmittance of zirconia in different thicknesses using various light curing units. MATERIALS AND METHODS A total of 21 disc-shaped zirconia specimens (5 mm in diameter) in different thicknesses (0.3, 0.5 and 0.8 mm) were prepared. The light transmittance of the specimens under three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) was compared by using a hand-held radiometer. Statistical significance was determined using two-way ANOVA (α=.05). RESULTS ANOVA revealed that thickness of zirconia and light curing unit had significant effects on light transmittance (P<.001). CONCLUSION Greater thickness of zirconia results in lower light transmittance. Light-emitting diodes light-curing units might be considered as effective as Plasma arc light-curing units or more effective than Quartz-tungsten-halogen light-curing units for polymerization of the resin-based materials. PMID:22737314

Transmittance jump in a thin aluminium layer during laser ablation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bykovsky, N E; Senatsky, Yu V; Pershin, S M

A jump in the transmittance (from ∼0.1% to ∼50% for ∼1 ns) of an optical gate on a Mylar film (a thin aluminium layer on a Lavsan substrate) irradiated by nanosecond (10{sup -7} – 10{sup -8} s) pulses of a neodymium laser with an intensity up to 0.1 GW cm{sup -2} has been recorded. The mechanism of a fast (10{sup -10} – 10{sup -11} s) increase in the transmittance of the aluminium layer upon its overheating (without boiling) to the metal – insulator phase-transition temperature is discussed. (interaction of laser radiation with matter. laser plasma)

Transmitter-induced glycogenolysis and gluconeogenesis in leech segmental ganglia.

PubMed

Pennington, A J; Pentreath, V W

1987-01-01

1. The utilization and control of glycogen stores were studied in the isolated segmental ganglia of the horse leech, Haemopis sanguisuga. The glycogen in the ganglia was extracted and assayed fluorimetrically and its cellular localization and turnover studied by autoradiography in conjunction with [3H] glucose. 2. The glycogen levels were measured after incubation with different neurotransmitters for 60 min at 28 degrees C. The results for each experimental ganglion were compared to a paired control ganglion, and the results analysed by paired t-tests. 3. Several transmitter substances (5-HT, octopamine, dopamine, noradrenaline, histamine) produced reductions in glycogen (glycogenolysis); other transmitters (glutamate, GABA) produced increases in glycogen (gluconeogenesis); others (adenosine, glycine) produced reductions or increases, depending on concentration. Acetylcholine had no effect on the glycogen levels. 4. Most of the glycogen in the ganglia is localized in the packet glial cells, which surround the neuron perikarya. Autoradiographic analysis demonstrated that the effects of histamine and dopamine were principally on the glycogen in the glial cells. 5. Adenylate cyclase was demonstrated by electron microscope histochemistry to be localized on the plasma membranes of the glial cells, and to a lesser extent on the neuronal membranes. 6. It is concluded that the changes in glycogen in the glial cells may be party controlled by transmitters via adenylate cyclase. This may provide a sensitive mechanism for coupling neuronal activity with energy metabolism.

47 CFR 74.1250 - Transmitters and associated equipment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Translator Stations and FM Broadcast Booster Stations § 74.1250 Transmitters and associated equipment. (a) FM translator and booster transmitting apparatus, and exciters employed to provide a locally generated and modulated input signal to translator and booster equipment, used by stations authorized under the provisions...

47 CFR 74.1250 - Transmitters and associated equipment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Translator Stations and FM Broadcast Booster Stations § 74.1250 Transmitters and associated equipment. (a) FM translator and booster transmitting apparatus, and exciters employed to provide a locally generated and modulated input signal to translator and booster equipment, used by stations authorized under the provisions...

47 CFR 74.1250 - Transmitters and associated equipment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Translator Stations and FM Broadcast Booster Stations § 74.1250 Transmitters and associated equipment. (a) FM translator and booster transmitting apparatus, and exciters employed to provide a locally generated and modulated input signal to translator and booster equipment, used by stations authorized under the provisions...

47 CFR 74.1250 - Transmitters and associated equipment.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Translator Stations and FM Broadcast Booster Stations § 74.1250 Transmitters and associated equipment. (a) FM translator and booster transmitting apparatus, and exciters employed to provide a locally generated and modulated input signal to translator and booster equipment, used by stations authorized under the provisions...