Artykuły w czasopismach: „Selective Pulses”

1

Ridge, Clark D., i Jamie D. Walls. "Pathway Selective Pulses". Journal of Physical Chemistry Letters 2, nr 19 (16.09.2011): 2478–82. http://dx.doi.org/10.1021/jz200998v.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

2

Gong, Zhaoyuan, i Jamie D. Walls. "Diffusion Selective Pulses". Journal of Physical Chemistry Letters 11, nr 2 (26.12.2019): 456–62. http://dx.doi.org/10.1021/acs.jpclett.9b03222.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

3

Kupce, E., i R. Freeman. "Polychromatic Selective Pulses". Journal of Magnetic Resonance, Series A 102, nr 1 (marzec 1993): 122–26. http://dx.doi.org/10.1006/jmra.1993.1079.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

4

Kemp-Harper, Richard, Peter Styles i Stephen Wimperis. "B1-Selective Pulses". Journal of Magnetic Resonance, Series A 123, nr 2 (grudzień 1996): 230–36. http://dx.doi.org/10.1006/jmra.1996.0243.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

5

Stevenson, Cagla, James P. J. Hall, Michael A. Brockhurst i Ellie Harrison. "Plasmid stability is enhanced by higher-frequency pulses of positive selection". Proceedings of the Royal Society B: Biological Sciences 285, nr 1870 (10.01.2018): 20172497. http://dx.doi.org/10.1098/rspb.2017.2497.

Pełny tekst źródła

Streszczenie:

Plasmids accelerate bacterial adaptation by sharing ecologically important traits between lineages. However, explaining plasmid stability in bacterial populations is challenging owing to their associated costs. Previous theoretical and experimental studies suggest that pulsed positive selection may explain plasmid stability by favouring gene mobility and promoting compensatory evolution to ameliorate plasmid cost. Here we test how the frequency of pulsed positive selection affected the dynamics of a mercury-resistance plasmid, pQBR103, in experimental populations of Pseudomonas fluorescens SBW25. Plasmid dynamics varied according to the frequency of Hg 2+ positive selection: in the absence of Hg 2+ plasmids declined to low frequency, whereas pulses of Hg 2+ selection allowed plasmids to sweep to high prevalence. Compensatory evolution to ameliorate the cost of plasmid carriage was widespread across the entire range of Hg 2+ selection regimes, including both constant and pulsed Hg 2+ selection. Consistent with theoretical predictions, gene mobility via conjugation appeared to play a greater role in promoting plasmid stability under low-frequency pulses of Hg 2+ selection. However, upon removal of Hg 2+ selection, plasmids which had evolved under low-frequency pulse selective regimes declined over time. Our findings suggest that temporally variable selection environments, such as those created during antibiotic treatments, may help to explain the stability of mobile plasmid-encoded resistance.

Style APA, Harvard, Vancouver, ISO itp.

6

Geen, Helen, i Ray Freeman. "Band-selective radiofrequency pulses". Journal of Magnetic Resonance (1969) 93, nr 1 (czerwiec 1991): 93–141. http://dx.doi.org/10.1016/0022-2364(91)90034-q.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

7

Xu, Ping, Xi-Li Wu i Ray Freeman. "User-friendly selective pulses". Journal of Magnetic Resonance (1969) 99, nr 2 (wrzesień 1992): 308–22. http://dx.doi.org/10.1016/0022-2364(92)90181-6.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

8

Bouhrara, Mustapha, i Jean-Marie Bonny. "B1mapping with selective pulses". Magnetic Resonance in Medicine 68, nr 5 (13.01.2012): 1472–80. http://dx.doi.org/10.1002/mrm.24146.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

9

Blechta, Vratislav, i Jan Schraml. "A selective INEPT experiment for the assignment of NMR lines of low-gyromagnetic ratio nuclei through long-range couplings". Collection of Czechoslovak Chemical Communications 56, nr 2 (1991): 258–61. http://dx.doi.org/10.1135/cccc19910258.

Pełny tekst źródła

Streszczenie:

A selective variant of the standard INEPT experiment is suggested. The selectivity is achieved by replacing the refocusing proton pulses of the standard INEPT pulse sequence with selective (DANTE) 180° pulses. Since this approach eliminates the undesirable influences of homo- and heteronuclear couplings, the sensitivity of the method is high. In the case of assigning 29Si NMR lines of trimethylsilylated compounds the pulse sequence can be further simplified and a pair of refocusing pulses can be eliminated from the refocusing period. Advantages of the simplified method are demonstrated.

Style APA, Harvard, Vancouver, ISO itp.

10

XU, SHUWU, YUNXIA HUANG i XIANMING JI. "SELECTIVE EXCITATION OF COHERENT ANTI-STOKES RAMAN SCATTERING VIA PHASE STEP MODULATION". Journal of Nonlinear Optical Physics & Materials 22, nr 01 (marzec 2013): 1350002. http://dx.doi.org/10.1142/s0218863513500021.

Pełny tekst źródła

Streszczenie:

It is known that femtosecond coherent anti-Stokes Raman scattering (CARS) method suffers from the drawback of poor selectivity between neighboring Raman energy levels due to the large bandwidth of the pulses. Quantum coherent control based on the ultrashort pulse shaping technique is a promising solution. In this paper, we propose a simple approach to realize the selective excitation of CARS spectra by shaping both the probe and pump pulses with the π phase step. By phase step modulation of the probe pulse, we show that the CARS signals between neighboring Raman energy levels can be greatly narrowed and differentiated, and then selective excitation can be realized by modulating both the probe and pump pulses. Finally, the mechanism of the selective excitation by population transfer is briefly discussed.

Style APA, Harvard, Vancouver, ISO itp.

11

Ordidge, Roger J. "Random noise selective excitation pulses". Magnetic Resonance in Medicine 5, nr 1 (lipiec 1987): 93–98. http://dx.doi.org/10.1002/mrm.1910050113.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

12

Conolly, Steven, John Pauly, Dwight Nishimura i Albert Macovsiu. "Two-dimensional selective adiabatic pulses". Magnetic Resonance in Medicine 24, nr 2 (kwiecień 1992): 302–13. http://dx.doi.org/10.1002/mrm.1910240211.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

13

Shen, J., i L. E. Lerner. "Selective Radiofrequency Pulses Minimizing Relaxation". Journal of Magnetic Resonance, Series A 112, nr 2 (luty 1995): 265–69. http://dx.doi.org/10.1006/jmra.1995.1044.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

14

Rosenfeld, Daniel, Shimon L. Panfil i Yuval Zur. "Optimization of Adiabatic Selective Pulses". Journal of Magnetic Resonance 126, nr 2 (czerwiec 1997): 221–28. http://dx.doi.org/10.1006/jmre.1997.1165.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

15

Masuda, Shumpei, Kuan Yen Tan i Mikio Nakahara. "Theoretical Study on Spin-Selective Coherent Electron Transfer in a Quantum Dot Array". Universe 6, nr 1 (22.12.2019): 2. http://dx.doi.org/10.3390/universe6010002.

Pełny tekst źródła

Streszczenie:

Recently, we proposed the spin-selective coherent electron transfer in a silicon-quantum-dot array. It requires temporal tuning of two pulses of an oscillating magnetic field and gate voltage control. This paper proposes a simpler method that requires a single pulse of oscillating magnetic field and gate voltage control. We examined the robustness of the control against the error in the pulse amplitude and the effect of the excited states relaxation to the control efficiency. In addition, we propose a novel control method based on a shortcuts-to-adiabaticity protocol, which utilizes two pulses but requires temporal control of the pulse amplitude for only one of them. We compared their efficiencies under the effect of realistic pulse amplitude errors and relaxation.

Style APA, Harvard, Vancouver, ISO itp.

16

Fratila, A. A. M., G. G. Gauglitz, A. Strohbücker i D. Radu. "Selective photothermolysis of spider veins and reticular varices with the long-pulsed Nd:YAG laser". Phlebologie 49, nr 01 (7.06.2019): 16–22. http://dx.doi.org/10.1055/a-0865-5296.

Pełny tekst źródła

Streszczenie:

AbstractThe therapy of spider veins, telangiectasia and reticular veins of lower extremities can be successfully performed with sclerotherapy or by using the long pulsed (LP) Nd:YAG laser. A matter of discussion, however, is how should laser parameters – such as wavelength, fluence, pulse duration, number of pulses – be utilized for effective and selective photothermolysis treatment without any side effects. The selective photothermolysis was introduced in 1983 by Anderson and Parrish 1 as a concept in laser treatment, meaning the selective thermal destruction of the target tissue (the chromophores – the light-absorption molecule is here the blood vessel) using a specific laser light wavelength, with minimal injury to surrounding tissue (the skin). The effectiveness of the selective photothermolysis process using an LP Nd:YAG laser at 1064 nm for the treatment of leg veins telangiectasias up to 2 mm in diameter, is the result of 30-years clinical experience sustained by patient satisfaction and photo documentation. The use of double and triple pulses seems to be the key of success in treating even larger vessels and has demonstrated superior safety and efficacy. Even bigger telangiectasias, reticular veins or other dilated veins on neckline, upper abdomen or in the face can be successfully treated with the LP Nd:YAG laser.

Style APA, Harvard, Vancouver, ISO itp.

17

Aebischer, Kathrin, Nino Wili, Zdeněk Tošner i Matthias Ernst. "Using nutation-frequency-selective pulses to reduce radio-frequency field inhomogeneity in solid-state NMR". Magnetic Resonance 1, nr 2 (9.09.2020): 187–95. http://dx.doi.org/10.5194/mr-1-187-2020.

Pełny tekst źródła

Streszczenie:

Abstract. Radio-frequency (rf) field inhomogeneity is a common problem in NMR which leads to non-ideal rotations of spins in parts of the sample. Often, a physical volume restriction of the sample is used to reduce the effects of rf-field inhomogeneity, especially in solid-state NMR where spacers are inserted to reduce the sample volume to the centre of the coil. We show that band-selective pulses in the spin-lock frame can be used to apply B1-field selective inversions to spins that experience selected parts of the rf-field distribution. Any frequency band-selective pulse can be used for this purpose, but we chose the family of I-BURP pulses (Geen and Freeman, 1991) for the measurements demonstrated here. As an example, we show that the implementation of such pulses improves homonuclear frequency-switched Lee–Goldburg decoupling in solid-state NMR.

Style APA, Harvard, Vancouver, ISO itp.

18

Carlson, J. W. "Exact solutions for selective-excitation pulses". Journal of Magnetic Resonance (1969) 94, nr 2 (wrzesień 1991): 376–86. http://dx.doi.org/10.1016/0022-2364(91)90115-a.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

19

McCoy, M. A., i L. Mueller. "Nonresonant effects of frequency-selective pulses". Journal of Magnetic Resonance (1969) 99, nr 1 (sierpień 1992): 18–36. http://dx.doi.org/10.1016/0022-2364(92)90152-w.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

20

Vidarsson, L., C. Cunningham, G. E. Gold i J. M. Pauly. "$T_{2}$-Selective Magnetization Preparation Pulses". IEEE Transactions on Medical Imaging 26, nr 7 (lipiec 2007): 981–89. http://dx.doi.org/10.1109/tmi.2007.897390.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

21

de Rochefort, Ludovic, Xavier Maître, Jacques Bittoun i Emmanuel Durand. "Velocity-selective RF pulses in MRI". Magnetic Resonance in Medicine 55, nr 1 (2005): 171–76. http://dx.doi.org/10.1002/mrm.20751.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

22

VINCENT, S. J. F., i C. ZWAHLEN. "ChemInform Abstract: Selective Pulses in NMR". ChemInform 29, nr 41 (19.06.2010): no. http://dx.doi.org/10.1002/chin.199841317.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

23

Bendall, M. Robin, i Thomas E. Skinner. "J Pulses for Multiplet-Selective NMR". Journal of Magnetic Resonance 141, nr 2 (grudzień 1999): 261–70. http://dx.doi.org/10.1006/jmre.1999.1884.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

24

Nilgens, H., P. Blumler, J. Paff i B. Blumich. "Selective Saturation with Low-Power Pulses". Journal of Magnetic Resonance, Series A 105, nr 1 (październik 1993): 108–12. http://dx.doi.org/10.1006/jmra.1993.1258.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

25

Borgnat, Pierre, Anne Lesage, Stefano Caldarelli i Lyndon Emsley. "Narrowband Linear Selective Pulses for NMR". Journal of Magnetic Resonance, Series A 119, nr 2 (kwiecień 1996): 289–94. http://dx.doi.org/10.1006/jmra.1996.0090.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

26

Kupce, E., J. Boyd i I. D. Campbell. "Short Selective Pulses for Biochemical Applications". Journal of Magnetic Resonance, Series B 106, nr 3 (marzec 1995): 300–303. http://dx.doi.org/10.1006/jmrb.1995.1049.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

27

Uhrin, D., A. Mele i R. A. Dwek. "Selective Inverse Correlation by Using Chemical-Shift-Selective Filters and Selective Pulses". Journal of Magnetic Resonance, Series A 101, nr 1 (styczeń 1993): 98–102. http://dx.doi.org/10.1006/jmra.1993.1015.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

28

Li, Na, Hao Zhang, Jing Jing Wang i T. Aaron Gulliver. "On Capacity of 60GHz TH-PPM Systems in Frequency Selective Fading Channels". Advanced Materials Research 433-440 (styczeń 2012): 5506–11. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.5506.

Pełny tekst źródła

Streszczenie:

Two pulse waveforms are designed and analyzed for 60GHz pulse modulation systems. An indoor frequency selective fading channel model is introduced for single user 60GHz TH-PPM systems. The capacity with this channel model of a 60GHz TH-PPM system based on the designed pulses is derived. Performance results are presented to illustrate the effects of the pulse waveforms and channel properties on the channel capacity.

Style APA, Harvard, Vancouver, ISO itp.

29

Архипов, Р. М., М. В. Архипов, А. В. Пахомов, М. О. Жукова, А. Н. Цыпкин i Н. Н. Розанов. "Селективное возбуждение и создание инверсной населенности в квантовых системах с помощью униполярных аттосекундных и терагерцовых импульсов". Журнал технической физики 128, nr 12 (2020): 1905. http://dx.doi.org/10.21883/os.2020.12.50328.197-20.

Pełny tekst źródła

Streszczenie:

The possibility of selective population of the energy levels of quantum systems was studied using a single unipolar subcycle pulse and a pair of pulses. Selective population of quantum levels is clearly illustrated based on the numerical solution of the system of equations for the density matrix of a three-level medium interacting with a pair of subcycle attosecond and terahertz pulses. The possibility of creating an population inversion in a three-level medium is shown using a pair of such pulses. The dynamics of population density gratings in a three-level medium is studied at the impact on the system of a pair of large-amplitude Gaussian pulses. If in a weak field the shape of the gratings is harmonic, according to analytical calculations performed according to perturbation theory, then in in the case of a strong field, the spatial profile of the gratings can differ from the sinusoidal one and has complex spike structure.

Style APA, Harvard, Vancouver, ISO itp.

30

Kuzmin E. V. i Klekovkin A.V. "Features of structuring and ablation of thin titanium films by femtosecond laser pulses". Optics and Spectroscopy 130, nr 4 (2022): 412. http://dx.doi.org/10.21883/eos.2022.04.53727.66-21.

Pełny tekst źródła

Streszczenie:

The processes of structuring and ablation of a titanium film by femtosecond laser pulses at wavelengths of 515 nm and 1030 nm have been studied in both single-pulse and multi-pulse modes. The optimal energy regimes for the selective removal of film material without damaging the substrate, as well as the regimes for the generation of the periodic structures on the surface, are determined. The evolution of periodic structures with an increase in the number of laser pulses is shown. The precision removal of titanium film is associated with thermomechanical explosive boiling and the corresponding energy contribution, which ensures the cascade appearance of ablation craters.. Keywords: thin films, femtosecond laser pulses, surface treatment

Style APA, Harvard, Vancouver, ISO itp.

31

Berger, Stefan. "NMR techniques employing selective radiofrequency pulses in combination with pulsed field gradients". Progress in Nuclear Magnetic Resonance Spectroscopy 30, nr 3-4 (lipiec 1997): 137–56. http://dx.doi.org/10.1016/s0079-6565(97)00003-4.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

32

Carlson, J. W. "Exact solutions for selective excitation pulses. II. Excitation pulses with phase control". Journal of Magnetic Resonance (1969) 97, nr 1 (marzec 1992): 65–78. http://dx.doi.org/10.1016/0022-2364(92)90237-2.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

33

MANSFIELD, R. J. ORDIDGE AND P., i J. A. B. LOHMAN AND S. B. PRIME. "Volume Selection Using Gradients and Selective Pulses". Annals of the New York Academy of Sciences 508, nr 1 Physiological (listopad 1987): 376–85. http://dx.doi.org/10.1111/j.1749-6632.1987.tb32919.x.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

34

Tait, Claudia E., i Stefan Stoll. "ENDOR with band-selective shaped inversion pulses". Journal of Magnetic Resonance 277 (kwiecień 2017): 36–44. http://dx.doi.org/10.1016/j.jmr.2017.02.007.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

35

Moore, Jay, Marcin Jankiewicz, Adam W. Anderson i John C. Gore. "Slice-selective excitation with -insensitive composite pulses". Journal of Magnetic Resonance 214 (styczeń 2012): 200–211. http://dx.doi.org/10.1016/j.jmr.2011.11.006.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

36

Lopez, Christopher J., Wei Lu i Jamie D. Walls. "Relaxation selective pulses in fast relaxing systems". Journal of Magnetic Resonance 242 (maj 2014): 95–106. http://dx.doi.org/10.1016/j.jmr.2014.02.006.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

37

Shinnar, Meir. "5572126 Reduced power selective excitation RF pulses". Magnetic Resonance Imaging 15, nr 4 (styczeń 1997): XVI. http://dx.doi.org/10.1016/s0730-725x(97)89057-1.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

38

Rourke, David E., Piotr Kozlowski, Beatrice G. Winsborrow i John K. Saunders. "The soliton-lattice algorithm and selective pulses". Magma: Magnetic Resonance Materials in Physics, Biology, and Medicine 2, nr 3 (październik 1994): 379–81. http://dx.doi.org/10.1007/bf01705277.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

39

O'Donnell, M., i W. J. Adams. "Selective time-reversal pulses for NMR imaging". Magnetic Resonance Imaging 3, nr 4 (styczeń 1985): 377–82. http://dx.doi.org/10.1016/0730-725x(85)90401-1.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

40

Conolly, Steven, Dwight Nishimura i Albert Macovski. "Sweep-diagram analysis of selective adiabatic pulses". Journal of Magnetic Resonance (1969) 83, nr 3 (lipiec 1989): 549–64. http://dx.doi.org/10.1016/0022-2364(89)90348-x.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

41

Mao, Jintong, T. H. Mareci, K. N. Scott i E. R. Andrew. "Selective inversion radiofrequency pulses by optimal control". Journal of Magnetic Resonance (1969) 70, nr 2 (listopad 1986): 310–18. http://dx.doi.org/10.1016/0022-2364(86)90016-8.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

42

Friedrich, Jan, Simon Davies i Ray Freeman. "Shaped selective pulses for coherence-transfer experiments". Journal of Magnetic Resonance (1969) 75, nr 2 (listopad 1987): 390–95. http://dx.doi.org/10.1016/0022-2364(87)90048-5.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

43

Shinnar, Meir. "Reduced power selective excitation radio frequency pulses". Magnetic Resonance in Medicine 32, nr 5 (listopad 1994): 658–60. http://dx.doi.org/10.1002/mrm.1910320516.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

44

Kessler, Horst, Siggi Mronga i Gerd Gemmecker. "Multi-dimensional NMR experiments using selective pulses". Magnetic Resonance in Chemistry 29, nr 6 (czerwiec 1991): 527–57. http://dx.doi.org/10.1002/mrc.1260290602.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

45

Carlson, J. W. "Nonlinear Phase Adjustment of Selective Excitation Pulses". Journal of Magnetic Resonance 147, nr 2 (grudzień 2000): 210–16. http://dx.doi.org/10.1006/jmre.2000.2201.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

46

Nuzillard, J. M., i R. Freeman. "Band-Selective Pulses Designed to Accommodate Relaxation". Journal of Magnetic Resonance, Series A 107, nr 1 (marzec 1994): 113–18. http://dx.doi.org/10.1006/jmra.1994.1056.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

47

Bernassau, J. M., i J. M. Nuzillard. "Selective HMBC Experiments Using Soft Inversion Pulses". Journal of Magnetic Resonance, Series B 103, nr 1 (styczeń 1994): 77–81. http://dx.doi.org/10.1006/jmrb.1994.1011.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

48

Kim, Vitalii, Iurii Semenov, Allen S. Kiester, Mark A. Keppler, Bennett L. Ibey, Joel N. Bixler, Ruben M. L. Colunga Biancatelli i Andrei G. Pakhomov. "Control of the Electroporation Efficiency of Nanosecond Pulses by Swinging the Electric Field Vector Direction". International Journal of Molecular Sciences 24, nr 13 (30.06.2023): 10921. http://dx.doi.org/10.3390/ijms241310921.

Pełny tekst źródła

Streszczenie:

Reversing the pulse polarity, i.e., changing the electric field direction by 180°, inhibits electroporation and electrostimulation by nanosecond electric pulses (nsEPs). This feature, known as “bipolar cancellation,” enables selective remote targeting with nsEPs and reduces the neuromuscular side effects of ablation therapies. We analyzed the biophysical mechanisms and measured how cancellation weakens and is replaced by facilitation when nsEPs are applied from different directions at angles from 0 to 180°. Monolayers of endothelial cells were electroporated by a train of five pulses (600 ns) or five paired pulses (600 + 600 ns) applied at 1 Hz or 833 kHz. Reversing the electric field in the pairs (180° direction change) caused 2-fold (1 Hz) or 20-fold (833 kHz) weaker electroporation than the train of single nsEPs. Reducing the angle between pulse directions in the pairs weakened cancellation and replaced it with facilitation at angles <160° (1 Hz) and <130° (833 kHz). Facilitation plateaued at about three-fold stronger electroporation compared to single pulses at 90–100° angle for both nsEP frequencies. The profound dependence of the efficiency on the angle enables novel protocols for highly selective focal electroporation at one electrode in a three-electrode array while avoiding effects at the other electrodes. Nanosecond-resolution imaging of cell membrane potential was used to link the selectivity to charging kinetics by co- and counter-directional nsEPs.

Style APA, Harvard, Vancouver, ISO itp.

49

Brui, E., S. Rapacchi, D. Bendahan i A. Andreychenko. "Reducing “slice cross-talk” effect in metamaterial assisted fast spin-echo MRI". Journal of Physics: Conference Series 2015, nr 1 (1.11.2021): 012023. http://dx.doi.org/10.1088/1742-6596/2015/1/012023.

Pełny tekst źródła

Streszczenie:

Abstract Imaging of subtle changes in hand structures is challenged by the limited image quality, especially at 1.5 T. Reduction of specific absorption rate in metamaterial-assisted 1.5 T MRI provides an opportunity to utilize efficient pulse sequences and to improve the quality of acquired images. This work is devoted to the assessment of potential improvements of slice selectivity and reducing a ”slice cross-talk” artifact, using fast spin-echo (FSE) pulse sequence together with a metamaterial-based coil. The slice selection in conventional T1-weighted FSE wrist imaging pulse sequences was modeled using a ”Bloch Equations Simulator”. Two types of pulses were compared: apodized SINC pulses (reference) common for clinical FSE, and optimized selective Shinnar–Le Roux (SLR) pulses constructed in the MATPULSE program. Regular and SLR-based FSE pulse sequences were tested in a phantom experiment with different gaps between slices to investigate the “slice cross-talk” artifact presence. Combining the utilization of the metamaterial-based coil with an SLR-based FSE provided 28 times lower energy deposition in a duty cycle, as compared to the regular FSE with a conventional transmit coil. When the slice gap was decreased from 100% to 0%, the “slice cross-talk” effect reduced the signal intensity by 16%-18% in the SLR-based FSE and by 23%-32% for the regular FSE. The use of SLR pulses together with the metamaterial-based coil allowed to reduce the ”slice cross-talk” effect in contiguous FSE, while still being within the safe SAR limits.

Style APA, Harvard, Vancouver, ISO itp.

50

Han, Su Young, Timothy McLennan, Katja Czieselsky i Allan E. Herbison. "Selective optogenetic activation of arcuate kisspeptin neurons generates pulsatile luteinizing hormone secretion". Proceedings of the National Academy of Sciences 112, nr 42 (6.10.2015): 13109–14. http://dx.doi.org/10.1073/pnas.1512243112.

Pełny tekst źródła

Streszczenie:

Normal reproductive functioning in mammals depends upon gonadotropin-releasing hormone (GnRH) neurons generating a pulsatile pattern of gonadotropin secretion. The neural mechanism underlying the episodic release of GnRH is not known, although recent studies have suggested that the kisspeptin neurons located in the arcuate nucleus (ARN) may be involved. In the present experiments we expressed channelrhodopsin (ChR2) in the ARN kisspeptin population to test directly whether synchronous activation of these neurons would generate pulsatile luteinizing hormone (LH) secretion in vivo. Characterization studies showed that this strategy targeted ChR2 to 70% of all ARN kisspeptin neurons and that, in vitro, these neurons were activated by 473-nm blue light with high fidelity up to 30 Hz. In vivo, the optogenetic activation of ARN kisspeptin neurons at 10 and 20 Hz evoked high amplitude, pulse-like increments in LH secretion in anesthetized male mice. Stimulation at 10 Hz for 2 min was sufficient to generate repetitive LH pulses. In diestrous female mice, only 20-Hz activation generated significant increments in LH secretion. In ovariectomized mice, 5-, 10-, and 20-Hz activation of ARN kisspeptin neurons were all found to evoke LH pulses. Part of the sex difference, but not the gonadal steroid dependence, resulted from differential pituitary sensitivity to GnRH. Experiments in kisspeptin receptor-null mice, showed that kisspeptin was the critical neuropeptide underlying the ability of ARN kisspeptin neurons to generate LH pulses. Together these data demonstrate that synchronized activation of the ARN kisspeptin neuronal population generates pulses of LH.

Style APA, Harvard, Vancouver, ISO itp.

Artykuły w czasopismach na temat „Selective Pulses”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych