What's the difference between precession and precessional?

Precession


Definition:

  • (n.) The act of going before, or forward.

Example Sentences:

  • (1) Self-reported and observer-rated signs and symptoms of nicotine withdrawal were assessed precessation and 2, 7, 14, 30, 90, and 180 days postcessation in smokers who quit on their own for 30 days.
  • (2) This review of basic physics of nuclear magnetic resonance (NMR) discusses precession of magnetic nuclei in a static external field, introduces the concept of the rotating frame, and describes excitation of nuclei by an RF field.
  • (3) By allowing a free precession interval before signal acquisition, time is left for field gradients to be switched and for undesirable transients to decay.
  • (4) We report in vitro and in vivo MR studies of hemorrhage using the gradient-echo pulse sequence, FISP (steady state free precession) and FLASH (spoiling of transverse magnetization) at 1.5 Tesla.
  • (5) Precession photographs from these crystal forms are very alike, suggesting the molecular packing to be similar in all three forms.
  • (6) Crystals were analyzed using precession photography and were assigned to trigonal space group R32 with unit cell dimensions a = b = 115 A, c = 385 A.
  • (7) The results obtained in a previous study using 131I fibrinogen in cancerous patients suggested a local intravascular clotting precess.
  • (8) According to the study of the 8 cases published since 1956 and of this personal case the precession of a benign porosyringeal tumour seems probable but has never been proved.
  • (9) Canavanine also affects regulatory and catalytic reactions of arginine metabolism, arginine uptake, formation of structural components, and other cellular precesses.
  • (10) The temperature, concentration and Larmor precession frequency dependences can be well described by the conception of fast exchange in a simple biphasic model of water molecules rotation in the first hydration layer with slight anisotropy of motion.
  • (11) The space group and unit cell dimensions were determined with a precession camera and a four-circle diffractometer to be C222(1), and a = 157.1 A, b = 85.5 A, and c = 79.7 A, respectively.
  • (12) Microperfusion of pertubular capillaries failed to demonstrate urinary precession of 3H-gentamicin over 14C-inulin, a finding which argues against a rapid transtubular secretory flux of gentamicin.
  • (13) When this residual phase coherency is utilized in conjunction with the fast SSFP (steady-state free precession) technique, both the FID and the echo signals can be obtained.
  • (14) Steady-state free precession (SSFP) pulse sequences can produce magnetic resonance (MR) images rapidly, in which cerebrospinal fluid (CSF) is several times more intense than the other tissues.
  • (15) The detector is stationary which causes a distortion that is negligible for precession angles less than 10 degrees.
  • (16) There exists an age-related precession of taurine uptake values by brush border membrane vesicles prepared from nursing rats from youngest to oldest.
  • (17) Naturally processed peptide fragments bound to MHC class II molecules are peptides of 13-17 amino acids which appear to be precessively truncated from the carboxy terminus, perhaps after binding to the MHC class II molecule.
  • (18) The space group was determined using screenless small-angle precession photographs, and was confirmed by analyzing area detector diffraction data with the XENGEN programs for indexing and refinement.
  • (19) In a series of 18 consecutive cases of acute significant inversion trauma to the ankle, a three-dimensional fast imaging with steady-state precession pulse sequence (3D FISP) was performed.
  • (20) Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels.

Precessional


Definition:

  • (a.) Of or pertaining to pression; as, the precessional movement of the equinoxes.

Example Sentences:

  • (1) It incorporates a stepping motor to drive the photomultiplier, two analog-to-digital converters, and a device which monitors precessional movement of the rotor.
  • (2) The increase of precessional motion of choline head by the inhalation anesthetic is apparently responsible for the changes.
  • (3) 31P NMR spectra of calf lens homogenates were obtained at 10 and 18 degrees C (below and above the cold cataract phase transition temperature, respectively) at 7.05 T. Effective rotational correlation times (tau 0,eff) for the major phosphorus metabolites present in cortical and nuclear bovine calf lens homogenates were derived from nonlinear least-squares analysis of R vs omega e (spectral intensity ratio vs precessional frequency about the effective field) data with the assumption of isotropic reorientational motion.
  • (4) Both CSF pulsation flow phenomena occurred secondary to harmonic modulation of proton precessional phase (temporal phase shift) by the unique pulsatile motion of spinal CSF when the repetition time was not an integral multiple of the pulsation period.
  • (5) Physiologic cerebrospinal fluid (CSF) pulsation causes a harmonic modulation of proton precessional phase with two-dimensional Fourier transform (2DFT) imaging, which results in predictable regions of signal loss and the presence of phase-shift images ("ghost images").
  • (6) Space group (P6322), parameters of the cell a-b-132 A, c = 122 A and distribution of spot intensities on precessional X-ray patterns were in full agreement with corresponding parameters for leucinaminopeptidase crystals from bovine eye lens.

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