A New Nuclear-Quadrupole Double-Resonance Technique based on Solid Effect

1997 ◽  
Vol 52 (4) ◽  
pp. 337-342 ◽  
Author(s):  
J. Seliger ◽  
V. Žagar
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Double Resonance ◽  
Spin Lattice Relaxation ◽  
New Technique ◽  
Simultaneous Application ◽  
Resonance Technique ◽  
Solid Effect ◽  
Nuclear Quadrupole ◽  
Rf Magnetic Field

Abstract A new nuclear-quadrupole double-resonance technique is described. It has a higher sensitivity and a higher resolution than the conventional nuclear-quadrupole double-resonance technique based on solid effect. The new technique involves magnetic field cycling between a high and a low static magnetic field and simultaneous application of two rf magnetic fields when the sample is in the low static magnetic field. A strong rf magnetic field induces "forbidden" simultaneous transitions in a magnetic (usually 1H) and in a quadrupole spin system and thus couples the two spin systems. A weak rf magnetic field induces transitions between the energy levels of the quadrupole nuclei and simulates a fast spin-lattice relaxation of the quadrupole nuclei when its frequency matches an NQR frequency. The sensitivity and resolution of the new technique are discussed and test measurements in tris-sarcosine calcium chloride are presented.

1H -14N Nuclear Quadrupole Double Resonance with Multiple Frequency Sweeps

1994 ◽  
Vol 49 (1-2) ◽  
pp. 31-34 ◽  
Author(s):  
J. Seliger ◽  
V. Žagar ◽  
R. Blinc
Keyword(s):  
Magnetic Field ◽  
Double Resonance ◽  
Experimental Results ◽  
New Technique ◽  
Multiple Frequency ◽  
Resonance Technique ◽  
Highly Sensitive ◽  
Field Cycling ◽  
Nuclear Quadrupole ◽  
Frequency Sweeps

Abstract A new highly sensitive 1H -14N nuclear quadrupole double resonance technique is presented which is based on magnetic field cycling and on the application of multiple frequency sweeps of an r.f. magnetic field. The sensitivity and the resolution o f the new technique are estimated. Some experimental results obtained by the new technique are presented.

Simultaneous application of cisplatin and static magnetic field enhances oxidative stress in HeLa cell line

2017 ◽  
Vol 53 (9) ◽  
pp. 783-790 ◽  
Author(s):  
Samaneh Kamalipooya ◽  
Parviz Abdolmaleki ◽  
Zahra Salemi ◽  
Fatemeh Javani Jouni ◽  
Jaber Zafari ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Magnetic Field ◽  
Hela Cell ◽  
Cell Line ◽  
Static Magnetic Field ◽  
Hela Cell Line ◽  
Simultaneous Application

scholarly journals Modification of Phytochemical Production and Antioxidant Activity of Dracocephalum Kotschyi Cells by Exposure to Static Magnetic Field and Magnetite Nanoparticles

2021 ◽  
Author(s):  
Marzieh Taghizadeh ◽  
Fatemeh Nasibi ◽  
Khosrow Khosrow Manouchehri kalantari ◽  
Mohsen Mohseni-Moghadam
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Magnetite Nanoparticles ◽  
High Performance ◽  
Culture Media ◽  
Cell Suspension Cultures ◽  
Simultaneous Exposure ◽  
Simultaneous Application ◽  
Enhanced Production ◽  
Dracocephalum Kotschyi

Abstract Dracocephlum kotschyi Boiss is a genus in Lamiaceae family and a medicinal herb native to Iran. The cell suspension cultures were treated by static magnetic field (SMF) and Fe3O4 magnetite nanoparticles (MNP) to understand the production yield of secondary metabolites. The treatment procedure was done by cultivating the cells either with 100 ppm MNP, SMFs, or simultaneous exposure to both MNP and SMFs. The SMF at 30 mT was uniformly applied to the cells either for 3 or 4 days with a 3 h per day or a 5 h per day intervals, respectively. The contents of phenolics and phytochemicals were then examined by high performance liquid chromatography and UV-Vis spectrophotometer. These treatments imposed oxidative stress and induced polyphenol oxidase and phenylalanine ammonia lyase, accompanied by enhanced production of phenolics, anthocyanins, flavonoids, and lignin. The highest membrane embrittlement and elicitation was found upon simultaneous application of the MNPs and SMFs, followed by the MNP and SMFs. The contents of naringin, rosmarinic acid, quercetin, thymol, carvacrol, apigenin, and rutin increased in the intracellular biomass of all treated cells and extracellular culture media. These findings propose the potential of these elicitors in simultaneous production and secretion of these phytochemicals into culture media.

Nuclear magnetic double resonance based on strong rf magnetic-field-induced coupling between spin systems

1975 ◽  
Vol 11 (1) ◽  
pp. 27-36 ◽  
Author(s):  
J. Seliger ◽  
R. Blinc ◽  
M. Mali ◽  
R. Osredkar ◽  
A. Prelesnik
Keyword(s):  
Magnetic Field ◽  
Double Resonance ◽  
Spin Systems ◽  
Rf Magnetic Field ◽  
Nuclear Magnetic

A Numerical Simulation Study on the Effects of Crucible Rotation and Magnetic Fields in Growth of SiGe by the Traveling Heater Method

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Youhei Takagi ◽  
Yasunori Okano ◽  
Sadik Dost
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Static Magnetic Field ◽  
Simulation Study ◽  
Concentration Field ◽  
Magnetic Field Direction ◽  
Simultaneous Application ◽  
Rotation Rates ◽  
Traveling Heater Method ◽  
Crucible Rotation

A numerical simulation study was carried out to shed light on the effects of applied crucible rotation and static magnetic field during the traveling heater method growth of bulk SiGe single crystals. The simulation results show that the application of crucible rotation weakens the radial silicon concentration gradient due to the effect of centrifugal force. The effects of applied static magnetic field direction and strength on the concentration field in the melt were also studied. It was found that the simultaneous application of crucible rotation and static magnetic field is best to grow large crystals with uniform composition. An optimum combination of crucible rotation rates and applied magnetic field strengths is determined.

Nitrogen-14 quadrupole cross-relaxation spectroscopy

1988 ◽  
Vol 416 (1850) ◽  
pp. 149-178 ◽  
Keyword(s):  
Magnetic Field ◽  
Double Resonance ◽  
Relaxation Times ◽  
High Sensitivity ◽  
Lattice Relaxation ◽  
Cross Relaxation ◽  
Spin Lattice Relaxation ◽  
Proton Relaxation ◽  
Spin Lattice ◽  
Quadrupole Resonance

Cross-relaxation spectroscopy can be used as a sensitive method of detecting 14 N quadrupole-resonance signals in hydrogen-containing solids. The 1 H spin system is polarized in a high magnetic field that is then reduced adiabatically to a much lower value satisfying the level­-crossing condition, when the 1 H Zeeman splitting matches one of the 14 N quadrupole splittings. If the 14 N spin–lattice relaxation time is much shorter than that of the 1 H nuclei, a drastic loss of 1 H polarization occurs that is measured by recording the residual 1 H magnetic resonance signal after the sample has been returned to the higher field. The experimental cycle can be run in several different ways according to the relative values of the 1 H spin–lattice relaxation times ( T 1 ) in high and low field, the 14 N spin–lattice relaxation ( T 1Q ) and cross-polarization times ( T CP ), all of which can markedly influence the spectra. The line shapes are broadened by the presence of the magnetic field and Zeeman shifts of the peak frequencies also occur, for which simple corrections may be derived. The methods used have high sensitivity, particularly if the ratio T 1 / T 1Q is large. They have the advantage over other double-resonance techniques in that long proton T 1 values are not necessary for the success of an experiment; it is also possible to select conditions in which the recovered 1 H signal is directly proportional to the relative numbers of 14 N nuclei present and the magnitude of the cross-relaxation field. Multi-proton relaxation jumps also give rise to signals at subharmonics of the fundamental, whose relative intensities reflect the extent to which the 14 N and 1 H relaxation is coupled via their dipole–dipole interactions, which are not completely quenched in the finite magnetic fields necessary in cross-relaxation spectroscopy. These conclusions are illustrated in a number of 14 N spectra of compounds in which quadrupole-resonance signals have not previously been recorded.

31P Spin-Lattice Relaxation Times and Resonance Linewidths of Rat Tissuein Vivo: Dependence upon the Static Magnetic Field Strength

1985 ◽  
Vol 2 (4) ◽  
pp. 410-417 ◽  
Author(s):  
Jeffrey L. Evelhoch ◽  
Coleen S. Ewy ◽  
Barry A. Siegfried ◽  
Joseph J. H. Ackerman ◽  
David W. Rice ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Static Magnetic Field ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice

1H - 17O Nuclear Quadrupole Double Resonance in DL-Proline

1990 ◽  
Vol 45 (5) ◽  
pp. 733-735 ◽  
Author(s):  
J. Seliger ◽  
V. Žagar ◽  
R. Blinc ◽  
P. K. Kadaba ◽  
D. Fiat
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Double Resonance ◽  
Unit Cell ◽  
The Other ◽  
Resonance Technique ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Abstract 17O nuclear quadrupole resonance spectra have been measured in an 17O enriched polycristalline sample of DL-proline with the help of 1H - 17O nuclear quadrupole double resonance technique. The results show the presence of eight chemically inequivalent oxygen sites corresponding to four inequivalent proline molecules in the unit cell. The oxygen sites may be grouped into two sets of four sites. One set with the short proton-oxygen distances belongs to the C - O • • • H groups whereas the other with the long proton-oxygen distances to the C = O groups

A Numerical Simulation Study on the Effects of Crucible Rotation and Magnetic Fields in Growth of SiGe by the Travelling Heater Method

2010 ◽  
Author(s):  
Youhei Takagi ◽  
Atsuko Ishida ◽  
Yasunori Okano ◽  
Sadik Dost
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Static Magnetic Field ◽  
Simulation Study ◽  
Concentration Field ◽  
Magnetic Field Direction ◽  
Simultaneous Application ◽  
Rotation Rates ◽  
Crucible Rotation ◽  
Shed Light

A numerical simulation study was carried out to shed light on the effects of applied crucible rotation and static magnetic field during the THM (travelling heater method) growth of bulk SiGe single crystals. The simulation results show that the application of crucible rotation weakens the radial silicon concentration gradient due to the effect of centrifugal force. The effects of applied static magnetic field direction and strength on the concentration field in the melt were also studied. It was found that the simultaneous application of crucible rotation and static magnetic field is best to grow large crystals with uniform composition. An optimum combination of crucible rotation rates and applied magnetic field strengths is determined.

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