The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
Maite Brandtpearce - One of the best experts on this subject based on the ideXlab platform.
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comparison of fwm and xpm induced crosstalk using the volterra series transfer function method
Journal of Lightwave Technology, 2003Co-Authors: Bo Xu, Maite BrandtpearceAbstract:New analytical tools to calculate the variance due to cross-phase modulation (XPM) and four-wave mixing (FWM) induced intensity distortion are derived based on the Volterra series transfer function method. The analysis for both the XPM and FWM effects is based on the same system configuration with a continuous-wave (CW) Probe Channel plus modulated pump Channels, which makes possible a fair comparison between the two nonlinear effects. Effective ways to reduce the XPM- and FWM-induced intensity distortion are given. The new results on the variance of the nonlinearity-induced intensity fluctuation also make it possible to study both synchronous wavelength-division multiplexing (WDM) systems with fixed Channel delays and asynchronous WDM systems with random Channel delays. The new analytical results provide accurate and efficient ways for system parameter optimization to reduce these two nonlinear effects.
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comparison of fwm and xpm induced crosstalk using the volterra series transfer function method
Journal of Lightwave Technology, 2003Co-Authors: Bo Xu, Maite BrandtpearceAbstract:New analytical tools to calculate the variance due to cross-phase modulation (XPM) and four-wave mixing (FWM) induced intensity distortion are derived based on the Volterra series transfer function method. The analysis for both the XPM and FWM effects is based on the same system configuration with a continuous-wave (CW) Probe Channel plus modulated pump Channels, which makes possible a fair comparison between the two nonlinear effects. Effective ways to reduce the XPM- and FWM-induced intensity distortion are given. The new results on the variance of the nonlinearity-induced intensity fluctuation also make it possible to study both synchronous wavelength-division multiplexing (WDM) systems with fixed Channel delays and asynchronous WDM systems with random Channel delays. The new analytical results provide accurate and efficient ways for system parameter optimization to reduce these two nonlinear effects.
Bo Xu - One of the best experts on this subject based on the ideXlab platform.
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comparison of fwm and xpm induced crosstalk using the volterra series transfer function method
Journal of Lightwave Technology, 2003Co-Authors: Bo Xu, Maite BrandtpearceAbstract:New analytical tools to calculate the variance due to cross-phase modulation (XPM) and four-wave mixing (FWM) induced intensity distortion are derived based on the Volterra series transfer function method. The analysis for both the XPM and FWM effects is based on the same system configuration with a continuous-wave (CW) Probe Channel plus modulated pump Channels, which makes possible a fair comparison between the two nonlinear effects. Effective ways to reduce the XPM- and FWM-induced intensity distortion are given. The new results on the variance of the nonlinearity-induced intensity fluctuation also make it possible to study both synchronous wavelength-division multiplexing (WDM) systems with fixed Channel delays and asynchronous WDM systems with random Channel delays. The new analytical results provide accurate and efficient ways for system parameter optimization to reduce these two nonlinear effects.
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comparison of fwm and xpm induced crosstalk using the volterra series transfer function method
Journal of Lightwave Technology, 2003Co-Authors: Bo Xu, Maite BrandtpearceAbstract:New analytical tools to calculate the variance due to cross-phase modulation (XPM) and four-wave mixing (FWM) induced intensity distortion are derived based on the Volterra series transfer function method. The analysis for both the XPM and FWM effects is based on the same system configuration with a continuous-wave (CW) Probe Channel plus modulated pump Channels, which makes possible a fair comparison between the two nonlinear effects. Effective ways to reduce the XPM- and FWM-induced intensity distortion are given. The new results on the variance of the nonlinearity-induced intensity fluctuation also make it possible to study both synchronous wavelength-division multiplexing (WDM) systems with fixed Channel delays and asynchronous WDM systems with random Channel delays. The new analytical results provide accurate and efficient ways for system parameter optimization to reduce these two nonlinear effects.
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Analysis of XPM-induced intensity distortion using the VSTF method
LEOS 2001. 14th Annual Meeting of the IEEE Lasers and Electro-Optics Society (Cat. No.01CH37242), 2001Co-Authors: Bo Xu, M. Brandt-pearceAbstract:We derive a new expression for the XPM-induced intensity distortion for a CW Probe Channel by using the Volterra series transfer function (VSTF) method. The new result can work in situations with both small and large dispersion. We also use the new result to study the effect of frequency chirping on the XPM-induced intensity distortion. For multiple span systems, the accumulated nonlinear phases which are frequency chirping for the input signals to the following spans will eventually become large enough to be nonnegligible.
Mark. G. Mcnamee - One of the best experts on this subject based on the ideXlab platform.
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Mouse–Torpedo Chimeric α-Subunit Used to Probe Channel-Gating Determinants on the Nicotinic Acetylcholine Receptor Primary Sequence
Cellular and Molecular Neurobiology, 1997Co-Authors: Daniel H. Butler, José A. Lasalde, Judy K. Butler, Shiori Tamamizu, Gregor Zimmerman, Mark. G. McnameeAbstract:1. To determine if structural domains are important for nicotinic acetylcholine receptor (nAChr) Channel function, six mouse– Torpedo chimeric α-subunits were constructed (Fig. 2) and coexpressed with Torpedo californica β-, γ-, and δ-subunits in Xenopus laevis oocytes. 2. nAChRs containing a chimeric α-subunit were examined by voltage- and patch-clamp methods to determine their functional characteristics. Dose–response curves from voltage-clamped oocytes were used to estimate EC_50's and Hill coefficients. Whole-cell currents were normalized against the α-bungarotoxin (α-BTX) binding sites to obtain normalized responses to acetylcholine (ACh). Open time constants at 4 μ M ACh were used to examine single-Channel behavior. 3. The EC_50 for ACh was modulated by the N-terminal half of the α-subunit. When the Torpedo subunit sequence between position 1 and position 268 was replaced by mouse sequence, the EC_50 shifted toward the value for the wild-type mouse subunit. Replacement of either the 1–159 or the 160–268 positions of the Torpedo sequence with the mouse sequence lowered the EC_50. This suggests that at least two regions play a role in determining the EC_50. 4. When the primary sequence (160–268) of the Torpedo α-subunit was introduced in the mouse α-subunit (T160–268), the expressed chimeric receptor was nonfunctional. The inverse chimera (M160–268) was functional and the open time constant and EC_50 were similar to those of mouse but the normalized response was characteristic of Torpedo . 5. The normalized macroscopic response to ACh (300 μ M ) of the chimera containing the mouse α-subunit showed a ninefold increase relative to the Torpedo wild type. Receptors which contain the C terminal of the mouse α-subunit also show an increase in the maximum normalized current. Receptors with the α-subunit which contain the Torpedo C-terminal sequence have a lower normalized response. 6. The combined results suggest that AChR Channel function is modulated by structural determinants within the primary sequence. These structural domains might modulate Channel function through specific allosteric interactions. The lack of response of the T160–268 chimera suggests that a critical interaction essential for the coupling of agonist binding and Channel gating was disrupted. This result suggests that the interaction of structural domains within the nAChR primary structure are essential for Channel function and that these intractions could be very specific within different nAChR species.
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Mouse-Torpedo chimeric alpha-subunit used to Probe Channel-gating determinants on the nicotinic acetylcholine receptor primary sequence.
Cellular and molecular neurobiology, 1997Co-Authors: Daniel H. Butler, José A. Lasalde, Judy K. Butler, Shiori Tamamizu, Gregor Zimmerman, Mark. G. McnameeAbstract:1. To determine if structural domains are important for nicotinic acetylcholine receptor (nAChr) Channel function, six mouse–Torpedo chimeric α-subunits were constructed (Fig. 2) and coexpressed with Torpedo californica β-, γ-, and δ-subunits in Xenopus laevis oocytes.
Daniel H. Butler - One of the best experts on this subject based on the ideXlab platform.
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Mouse–Torpedo Chimeric α-Subunit Used to Probe Channel-Gating Determinants on the Nicotinic Acetylcholine Receptor Primary Sequence
Cellular and Molecular Neurobiology, 1997Co-Authors: Daniel H. Butler, José A. Lasalde, Judy K. Butler, Shiori Tamamizu, Gregor Zimmerman, Mark. G. McnameeAbstract:1. To determine if structural domains are important for nicotinic acetylcholine receptor (nAChr) Channel function, six mouse– Torpedo chimeric α-subunits were constructed (Fig. 2) and coexpressed with Torpedo californica β-, γ-, and δ-subunits in Xenopus laevis oocytes. 2. nAChRs containing a chimeric α-subunit were examined by voltage- and patch-clamp methods to determine their functional characteristics. Dose–response curves from voltage-clamped oocytes were used to estimate EC_50's and Hill coefficients. Whole-cell currents were normalized against the α-bungarotoxin (α-BTX) binding sites to obtain normalized responses to acetylcholine (ACh). Open time constants at 4 μ M ACh were used to examine single-Channel behavior. 3. The EC_50 for ACh was modulated by the N-terminal half of the α-subunit. When the Torpedo subunit sequence between position 1 and position 268 was replaced by mouse sequence, the EC_50 shifted toward the value for the wild-type mouse subunit. Replacement of either the 1–159 or the 160–268 positions of the Torpedo sequence with the mouse sequence lowered the EC_50. This suggests that at least two regions play a role in determining the EC_50. 4. When the primary sequence (160–268) of the Torpedo α-subunit was introduced in the mouse α-subunit (T160–268), the expressed chimeric receptor was nonfunctional. The inverse chimera (M160–268) was functional and the open time constant and EC_50 were similar to those of mouse but the normalized response was characteristic of Torpedo . 5. The normalized macroscopic response to ACh (300 μ M ) of the chimera containing the mouse α-subunit showed a ninefold increase relative to the Torpedo wild type. Receptors which contain the C terminal of the mouse α-subunit also show an increase in the maximum normalized current. Receptors with the α-subunit which contain the Torpedo C-terminal sequence have a lower normalized response. 6. The combined results suggest that AChR Channel function is modulated by structural determinants within the primary sequence. These structural domains might modulate Channel function through specific allosteric interactions. The lack of response of the T160–268 chimera suggests that a critical interaction essential for the coupling of agonist binding and Channel gating was disrupted. This result suggests that the interaction of structural domains within the nAChR primary structure are essential for Channel function and that these intractions could be very specific within different nAChR species.
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Mouse-Torpedo chimeric alpha-subunit used to Probe Channel-gating determinants on the nicotinic acetylcholine receptor primary sequence.
Cellular and molecular neurobiology, 1997Co-Authors: Daniel H. Butler, José A. Lasalde, Judy K. Butler, Shiori Tamamizu, Gregor Zimmerman, Mark. G. McnameeAbstract:1. To determine if structural domains are important for nicotinic acetylcholine receptor (nAChr) Channel function, six mouse–Torpedo chimeric α-subunits were constructed (Fig. 2) and coexpressed with Torpedo californica β-, γ-, and δ-subunits in Xenopus laevis oocytes.
L Van Wüllen - One of the best experts on this subject based on the ideXlab platform.
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13C–27Al TRAPDOR and REDOR Experiments for the Detection of 13C–27Al Dipolar Interactions in Solids
Journal of magnetic resonance (San Diego Calif. : 1997), 1999Co-Authors: L Van Wüllen, Martin KalweiAbstract:Abstract We report 13C–27Al double resonance experiments (REDOR and TRAPDOR) on several aluminum organic compounds with the aim of detecting 13C–27Al dipolar couplings and distances in solids. The 13C and 27Al pulses are applied to the same Probe Channel because their resonance frequencies are in close proximity. The different possibilities of controlling the efficiency of the TRAPDOR approach (by varying the 27Al RF amplitude and the MAS frequency) are investigated. The results indicate that TRAPDOR is superior to REDOR in resolving differences in 13C–27Al distances when choosing the proper experimental conditions. Where known, the crystal structure data are in qualitative agreement with the distance information extracted from our experiments. The experiment should be very valuable in different fields of solid state chemistry, where the interaction of organic and inorganic sample fractions is of fundamental importance.
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triple resonance transfer of populations in double resonance experiments for the detection of dipolar interactions
Solid State Nuclear Magnetic Resonance, 1998Co-Authors: L Van WüllenAbstract:Abstract A 13 C { 1 H } CPMAS { 27 Al } TRAPDOR NMR experiment is reported with the aim of detecting 13 C − 27 Al proximities and distances in solids. The 13 C and 27 Al pulses are applied to the same Probe Channel, because their resonance frequencies lie extremely close to each other. The study of the heteronuclear dipolar interaction between these two nuclei, which are of fundamental importance in solid state science, is not possible with standard double resonance approaches. Results are presented for the model compound aluminum lactate. The 13 C signals for the three lactate carbons show different magnitudes of the TRAPDOR effect, in excellent agreement with their mean Al–C distances, calculated from crystal structure data. The results illustrate the feasibility of this method for the study of systems where the interaction of organic and inorganic fractions is directing the structure (template/zeolite) or controlling the catalytic efficiency (organic reactant/catalytically active sites in zeolites or clays).
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1H-13C-27Al triple resonance transfer of populations in double resonance experiments for the detection of 13C-27Al dipolar interactions.
Solid state nuclear magnetic resonance, 1998Co-Authors: L Van WüllenAbstract:A 13C [1H] CPMAS [27Al] TRAPDOR NMR experiment is reported with the aim of detecting 13C-27Al proximities and distances in solids. The 13C and 27Al pulses are applied to the same Probe Channel, because their resonance frequencies lie extremely close to each other. The study of the heteronuclear dipolar interaction between these two nuclei, which are of fundamental importance in solid state science, is not possible with standard double resonance approaches. Results are presented for the model compound aluminum lactate. The 13C signals for the three lactate carbons show different magnitudes of the TRAPDOR effect, in excellent agreement with their mean Al-C distances, calculated from crystal structure data. The results illustrate the feasibility of this method for the study of systems where the interaction of organic and inorganic fractions is directing the structure (template/zeolite) or controlling the catalytic efficiency (organic reactant/catalytically active sites in zeolites or clays).