The spinal antinociceptive effects of cholinergic drugs in rats: receptor subtype specificity in different nociceptive tests

BACKGROUND: Several studies have shown that muscarinic cholinergic agonists cause antinociception in humans and animals when given by both spinal and non-spinal parenteral routes. It is uncertain which subtype of muscarinic receptor is involved in spinally mediated antinociceptive effects caused by these drugs. The cholinergic receptor agonists McN-A-343 (M(1 )selective; 3.89 to 389 nmol) and carbachol (non-selective; 0.029 to 29 nmol) were used in a rat acute pain model to investigate the involvement of M(1 )and non-M(1 )subtypes in spinally mediated antinociception. The drugs were injected intrathecally and results from experiments in which drug actions were carefully confined to the spinal cord were used to construct agonist dose response curves. RESULTS: McN-A-343 frequently diffused rostrally to the brain, away from the lumbosacral site of injection. Thus, in spite of its receptor subtype selectivity, McN-A-343 is a poor probe to use in attempting to identify receptor subtypes involved in spinal cord antinociceptive systems. However, in some experiments McN-A-343 caused spinally mediated antinociception assessed by the electrical current threshold test. Antinociception assessed by the tail flick latency test with intrathecal McN-A-343 was observed and found to involve supraspinal mechanisms. Carbachol caused spinally mediated antinociception assessed by both electrical current threshold and tail flick latency. CONCLUSIONS: The results suggest that M(1 )receptors are involved in spinally mediated antinociception revealed by electrical current threshold; other cholinergic receptors (non-M(1)) are involved in thermal antinociception at the spinal cord. This contrasts with previous work on spinally mediated cholinergic antinociception. These differences are believed to be due to difficulties in restricting the action of these drugs to the spinal cord

Magnetic field dependence of the maximum magnetic entropy change

The maximum isothermal entropy change in a magnetic refrigerant with a second-order phase transition is shown to depend on applied magnetic field H as follows: (-ΔS)max = A(H + H0)2/3 – AH02/3 + BH4/3. Here A and B are intrinsic parameters of the cooling material and H0 is an extrinsic parameter determined by the purity and homogeneity of the sample. This theoretical prediction is confirmed by measurements on variously pure poly- and single-crystalline samples of Gd. The Curie point of pure Gd is found to be 295(1) K; however, the maximum of -ΔSM is attained at a lower temperature: The higher the quality of the sample, the closer the peak position to 295 K. Further tests are reported for a series of melt-spun LaFe13-xSix alloys. These are found to follow the same field dependence, despite the fact that for certain compositions (x \u3c 1.8) they experience a phase transition of first, rather than second, order

Fabrication of highly dense isotropic Nd-Fe-B bonded magnets via extrusion-based additive manufacturing

Isotropic bonded magnets with a high loading fraction of 70 vol.% Nd-Fe-B are fabricated via an extrusion-based additive manufacturing, or 3D printing system that enables rapid production of large parts for the first time. The density of the printed magnet is 5.15 g/cm3. The room temperature magnetic properties are: intrinsic coercivity Hci = 8.9 kOe (708.2 kA/m), remanence Br = 5.8 kG (0.58 Tesla), and energy product (BH)max = 7.3 MGOe (58.1 kJ/m3). The as-printed magnets are then coated with two types of polymers, both of which improve the thermal stability at 127 {\deg}C as revealed by flux aging loss measurements. Tensile tests performed at 25 {\deg}C and 100 {\deg}C show that the ultimate tensile stress (UTS) increases with increasing loading fraction of the magnet powder, and decreases with increasing temperature. AC magnetic susceptibility and resistivity measurements show that the 3D printed Nd-Fe-B bonded magnets exhibit extremely low eddy current loss and high resistivity. Finally, we show that through back electromotive force measurements that motors installed with 3D printed Nd-Fe-B magnets exhibit similar performance as compared to those installed with sintered ferrites

Magnetic field dependence of the maximum magnetic entropy change

The maximum isothermal entropy change in a magnetic refrigerant with a second-order phase transition is shown to depend on applied magnetic field H as follows: (-ΔS)max = A(H + H0)2/3 – AH02/3 + BH4/3. Here A and B are intrinsic parameters of the cooling material and H0 is an extrinsic parameter determined by the purity and homogeneity of the sample. This theoretical prediction is confirmed by measurements on variously pure poly- and single-crystalline samples of Gd. The Curie point of pure Gd is found to be 295(1) K; however, the maximum of -ΔSM is attained at a lower temperature: The higher the quality of the sample, the closer the peak position to 295 K. Further tests are reported for a series of melt-spun LaFe13-xSix alloys. These are found to follow the same field dependence, despite the fact that for certain compositions (x This article is from Physical Review B 83 (2011): 012403, doi:10.1103/PhysRevB.83.012403.</p

Fabrication of highly dense isotropic Nd-Fe-B nylon bonded magnets via extrusion-based additive manufacturing

Magnetically isotropic bonded magnets with a high loading fraction of 70 vol.% Nd-Fe-B are fabricated via an extrusion-based additive manufacturing, or 3D printing system that enables rapid production of large parts. The density of the printed magnet is ∼ 5.2 g/cm3. The room temperature magnetic properties are: intrinsic coercivity Hci  = 8.9 kOe (708.2 kA/m), remanence Br  = 5.8 kG (0.58 T), and energy product (BH)max = 7.3 MGOe (58.1 kJ/m3). The as-printed magnets are then coated with two types of polymers, both of which improve the thermal stability as revealed by flux aging loss measurements. Tensile tests performed at 25 °C and 100 °C show that the ultimate tensile stress (UTS) increases with increasing loading fraction of the magnet powder, and decreases with increasing temperature. AC magnetic susceptibility and resistivity measurements show that the 3D printed Nd-Fe-B bonded magnets exhibit extremely low eddy current loss and high resistivity. Finally, we demonstrate the performance of the 3D printed magnets in a DC motor configuration via back electromotive force measurements.This is a manuscript of an article published as Li, Ling, Kodey Jones, Brian Sales, Jason L. Pries, I. C. Nlebedim, Ke Jin, Hongbin Bei, Brian K. Post, Michael S. Kesler, Orlando Rios, Vlastimil Kunc, Robert Fredette, John Ormerod, Aaron Williams, Thomas A. Lograsso, and M. Parans Paranthaman. "Fabrication of highly dense isotropic Nd-Fe-B nylon bonded magnets via extrusion-based additive manufacturing." Additive Manufacturing 21 (2018): 495-500. DOI: 10.1016/j.addma.2018.04.001. Posted with permission.</p

Manufacturing Processes for Permanent Magnets: Part II—Bonding and Emerging Methods

Permanent magnets produce magnetic fields and maintain the field even in the presence of an opposing magnetic field. They are widely used in electric machines, electronics, and medical devices. Part I reviews the conventional manufacturing processes for commercial magnets, including Nd-Fe-B, Sm-Co, alnico, and ferrite in cast and sintered forms. In Part II, bonding, emerging advanced manufacturing processes, as well as magnet recycling methods are briefly reviewed for their current status, challenges, and future directions.This article is published as Cui, Jun, John Ormerod, David S. Parker, Ryan Ott, Andriy Palasyuk, Scott McCall, Mariappan Parans Paranthaman et al. "Manufacturing Processes for Permanent Magnets: Part II—Bonding and Emerging Methods." JOM 74, no. 6 (2022): 2492-2506. DOI: 10.1007/s11837-022-05188-1. Copyright 2022 The Author(s). Attribution 4.0 International (CC BY 4.0). Posted with permission. DOE Contract Number(s): AC05-00OR22725; AC02-07CH11358; AC52- 07NA27344

Manufacturing Processes for Permanent Magnets: Part I—Sintering and Casting

Permanent magnets (PMs) produce magnetic fields and maintain the field even in the presence of an opposing magnetic field. Electrical machines using permanent magnets are more efficient than those without. Currently, all known strong magnets contain rare earth (RE) elements, and they are core components of a wide range of applications including electric vehicles and wind turbines. RE elements such as Nd and Dy have become critical materials due to the growing demand and constrained supply. Improving the manufacturing process is effective in mitigating the RE criticality issue by reducing waste and improving parts consistency. In this article, the state of the industry for PM is reviewed in detail considering both the technical and economic drivers. The importance of RE elements is discussed along with their economic importance to green energy. The conventional sintering and casting manufacturing processes for commercial magnets, including Nd-Fe-B, Sm-Co, Alnico, and ferrite, are described in detail.This article is published as Cui, Jun, John Ormerod, David Parker, Ryan Ott, Andriy Palasyuk, Scott Mccall, M. Parans Paranthaman et al. "Manufacturing processes for permanent magnets: Part I—sintering and casting." JOM 74, no. 4 (2022): 1279-1295. DOI: 10.1007/s11837-022-05156-9. Copyright 2022 The Author(s). Attribution 4.0 International (CC BY 4.0). Posted with permission. DOE Contract Number(s): AC05-00OR22725; AC02-07CH11358; AC52-07NA27344