scholarly journals WATER IMBIBITION AND RADICLE GROWTH OF GERMINATING PEA, CORN, AND SOYBEAN SEEDS ORIENTED TO THE EAST, SOUTH, WEST, AND NORTH IN SIX DIFFERENT MAGNETIC FIELDS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 671b-671
Author(s):  
Benjamin Liang ◽  
John M. Brown

Magnetic Resonance Imaging (MRI) is currently considered as a nondestructive and noninvasive method for observing the distribution, concentration, and status of water in biological materials. However, effects of static magnetic fields of MRI systems on plant growth and development remain controversial. This study was conducted to investigate the water imbibition and radicle growth of Pisum sativum (cv. Little Marvel), Zea mays (cv. Pioneer 3379), and Glycine max (cv. Forrest) seeds oriented to four directions and exposed to six different magnetic field strengths commonly used in MRI systems. Seeds were embedded in a water saturated synthetic foam medium, and were oriented, with respect to their hilum or embryo, to the east, south, west, or north. Seeds were then exposed to either 2, 4, 6, 8, 10, or 15 kilogauss static magnetic fields for 48 hours (water imbibition) or 54 hours (radicle growth). The orientation of seeds and the magnetic field strengths had no effect on water imbibition or radicle growth of seeds tested. However, long term exposure retarded pea radicle growth in 2 KG treatment, enhanced soybean radicle growth in 10 KG treatment, but had no effect on corn radicle growth.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1074F-1074
Author(s):  
Benjamin Liang ◽  
John M. Brown

Nuclear Magnetic Resonance Imaging is currently being investigated as a nondestructively and noninvasively observing plant-water relationships, Researchers have not considered the effects of magnetic fields on plant growth and development. This study was conducted to investigate the effects of magnetic fields on seed water imbibition and radicle growth. Corn (cv. pioneer 3379), pea (cv. little marvel), and soybean (cvs. forrest and D86-4669) seeds were embedded in petri dishes with water saturated Smither's oasis porus foam, and were oriented for the East, South, West, and North. Seeds were exposed to either 1.5 Tesla or 1×10-10 Tesla static magnetic field for 48 hours. Changes in seed weights and radicle lengths were measured. Results showed that the strong magnetic field and seed orientations had no effect on the water imbibition rate. However, growth of corn and pea radicles was affected by the magnetic field. The 1.5 Tesla magnetic field enhanced the growth of corn radicle length, whereas it retarded the growth of pea radicles.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1074f-1074
Author(s):  
Benjamin Liang ◽  
John M. Brown

Nuclear Magnetic Resonance Imaging is currently being investigated as a nondestructively and noninvasively observing plant-water relationships, Researchers have not considered the effects of magnetic fields on plant growth and development. This study was conducted to investigate the effects of magnetic fields on seed water imbibition and radicle growth. Corn (cv. pioneer 3379), pea (cv. little marvel), and soybean (cvs. forrest and D86-4669) seeds were embedded in petri dishes with water saturated Smither's oasis porus foam, and were oriented for the East, South, West, and North. Seeds were exposed to either 1.5 Tesla or 1×10-10 Tesla static magnetic field for 48 hours. Changes in seed weights and radicle lengths were measured. Results showed that the strong magnetic field and seed orientations had no effect on the water imbibition rate. However, growth of corn and pea radicles was affected by the magnetic field. The 1.5 Tesla magnetic field enhanced the growth of corn radicle length, whereas it retarded the growth of pea radicles.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ameni Kthiri ◽  
Selma Hamimed ◽  
Abdelhak Othmani ◽  
Ahmed Landoulsi ◽  
Siobhan O’Sullivan ◽  
...  

AbstractThe bacteriocidal properties of silver nanoparticles (AgNPs) depend on their average diameter (toxicity increases with decreasing diameter). In the present work, we describe novel green chemistry biosynthesis of AgNPs from AgNO3 added to cell-free culture medium of baker’s yeast, Saccharomyces cerevisiae, yielding nanoparticles in the range 11–25 nm. However, when yeast was grown in a moderate static magnetic field, AgNPs obtained from the resulting cell-free culture medium, were significantly smaller (2–12 nm) than those obtained without magnetic field. These latter nanoparticles were highly crystalline, stable and near-uniform shape. Furthermore, the antibacterial activity of AgNPs obtained from static magnetic fields were greater than those from control cultures. Static magnetic fields show a promising ability to generate biocidal nanoparticles via this novel green chemistry approach.


Author(s):  
J. Pierrus

Wherever possible, an attempt has been made to structure this chapter along similar lines to Chapter 2 (its electrostatic counterpart). Maxwell’s magnetostatic equations are derived from Ampere’s experimental law of force. These results, along with the Biot–Savart law, are then used to determine the magnetic field B arising from various stationary current distributions. The magnetic vector potential A emerges naturally during our discussion, and it features prominently in questions throughout the remainder of this book. Also mentioned is the magnetic scalar potential. Although of lesser theoretical significance than the vector potential, the magnetic scalar potential can sometimes be an effective problem-solving device. Some examples of this are provided. This chapter concludes by making a multipole expansion of A and introducing the magnetic multipole moments of a bounded distribution of stationary currents. Several applications involving magnetic dipoles and magnetic quadrupoles are given.


1990 ◽  
Vol 140 ◽  
pp. 459-462
Author(s):  
Richard G. Strom

Faraday depolarization estimates of thermal densities within the components of double radio sources agree well with estimates from X-ray observations of hot halos around early-type galaxies, provided magnetic field strengths are close to their equipartition values. Internal Faraday dispersion is the main cause of the depolarization observed.


1990 ◽  
Vol 140 ◽  
pp. 241-241
Author(s):  
A. J. Fitt ◽  
P. Alexander

We have calculated equipartition magnetic fields for a complete, optically-selected sample of 165 spiral galaxies. The magnetic field distribution (fig. 1) is type independent, and shows remarkably little spread in values, around 1 decade in B. This is not due to selection effects because of the nature of the sample and the 95 percent detection rate.


2019 ◽  
Vol 627 ◽  
pp. A11
Author(s):  
I. O. I. Virtanen ◽  
I. I. Virtanen ◽  
A. A. Pevtsov ◽  
L. Bertello ◽  
A. Yeates ◽  
...  

Aims. The evolution of the photospheric magnetic field has only been regularly observed since the 1970s. The absence of earlier observations severely limits our ability to understand the long-term evolution of solar magnetic fields, especially the polar fields that are important drivers of space weather. Here, we test the possibility to reconstruct the large-scale solar magnetic fields from Ca II K line observations and sunspot magnetic field observations, and to create synoptic maps of the photospheric magnetic field for times before modern-time magnetographic observations. Methods. We reconstructed active regions from Ca II K line synoptic maps and assigned them magnetic polarities using sunspot magnetic field observations. We used the reconstructed active regions as input in a surface flux transport simulation to produce synoptic maps of the photospheric magnetic field. We compared the simulated field with the observed field in 1975−1985 in order to test and validate our method. Results. The reconstruction very accurately reproduces the long-term evolution of the large-scale field, including the poleward flux surges and the strength of polar fields. The reconstruction has slightly less emerging flux because a few weak active regions are missing, but it includes the large active regions that are the most important for the large-scale evolution of the field. Although our reconstruction method is very robust, individual reconstructed active regions may be slightly inaccurate in terms of area, total flux, or polarity, which leads to some uncertainty in the simulation. However, due to the randomness of these inaccuracies and the lack of long-term memory in the simulation, these problems do not significantly affect the long-term evolution of the large-scale field.


2018 ◽  
Vol 39 (10) ◽  
pp. e1150-e1159 ◽  
Author(s):  
Bryan K. Ward ◽  
Yoon H. Lee ◽  
Dale C. Roberts ◽  
Ethan Naylor ◽  
Americo A. Migliaccio ◽  
...  

2019 ◽  
Vol 121 (6) ◽  
pp. 2013-2019 ◽  
Author(s):  
Bryan K. Ward ◽  
Dale C. Roberts ◽  
Jorge Otero-Millan ◽  
David S. Zee

For many years, people working near strong static magnetic fields of magnetic resonance imaging (MRI) machines have reported dizziness and sensations of vertigo. The discovery a decade ago that a sustained nystagmus can be observed in all humans with an intact labyrinth inside MRI machines led to a possible mechanism: a Lorentz force occurring in the labyrinth from the interactions of normal inner ear ionic currents and the strong static magnetic fields of the MRI machine. Inside an MRI, the Lorentz force acts to induce a constant deflection of the semicircular canal cupula of the superior and lateral semicircular canals. This inner ear stimulation creates a sensation of rotation, and a constant horizontal/torsional nystagmus that can only be observed when visual fixation is removed. Over time, the brain adapts to both the perception of rotation and the nystagmus, with the perception usually diminishing over a few minutes, and the nystagmus persisting at a reduced level for hours. This observation has led to discoveries about how the central vestibular mechanisms adapt to a constant vestibular asymmetry and is a useful model of set-point adaptation or how homeostasis is maintained in response to changes in the internal milieu or the external environment. We review what is known about the effects of stimulation of the vestibular system with high-strength magnetic fields and how the understanding of the mechanism has been refined since it was first proposed. We suggest future ways that magnetic vestibular stimulation might be used to understand vestibular disease and how it might be treated.


2019 ◽  
Vol 70 (3) ◽  
pp. 253-255
Author(s):  
Ömer Zor

Abstract We investigated the interaction energy of a Gilbertian magnetic charge with each of the “point” magnetic field sources. Finally we extrapolated a Dirac string can only be defined if there is at most one Dirac monopole in the medium. If there is only one Dirac monopole/string in the universe, the probability of detecting it is essential zero, such that Dirac’s monopole would remain just a “theorist’s particle”.


Sign in / Sign up

Export Citation Format

Share Document