Spin and Spin Current -- From Fundamentals to Recent Progresses

Along with the progress of the spin science and spintronics research, the flow of electron spins, \emph{i.e.}, spin current, has come to attract attention. New phenomena and electronic states were explained one after another using the concept of spin current. Moreover, as many of the conventionally known spintronics phenomena became well organized based on spin current it has rapidly been recognized as an essential concept in a wide range of condensed matter physics. In this article, we focus on recent developments in the physics of spin, spin current, and their related phenomena, where the conversion between spin angular momentum and different forms of angular momentum plays an essential role. Starting with an introduction to spin current, we first discuss the recent progress in the spintronic phenomena driven by spin-exchange coupling: spin pumping, topological Hall torque, and emergent inductor. We then extend our discussion to the interaction/interconversion of spins with heat, lattice vibrations, and charge current and address recent progress and perspectives on the spin Seebeck and Peltier effects. Next, we review the interaction between mechanical motion and electron/nuclear spins and argue the difference between the Barnett field and the rotational Doppler effect. We show that the Barnett effect reveals the angular momentum compensation temperature, at which the net angular momentum is quenched in ferrimagnets.Comment: 23 pages, 18 figure

LTP induction within a narrow critical period of immature stages enhances the survival of newly generated neurons in the adult rat dentate gyrus

Neurogenesis occurs in the adult hippocampus of various animal species. A substantial fraction of newly generated neurons die before they mature, and the survival rate of new neurons are regulated in an experience-dependent manner. Previous study showed that high-frequency stimulation (HFS) of perforant path fibers to the hippocampal dentate gyrus (DG) induces the long-term potentiation (LTP) in the DG, and enhances the survival of newly generated neurons in the DG. In this study, we addressed whether a time period exists during which the survival of new neurons is maximally sensitive to the HFS. We found that the enhancement of cell survival by HFS was exclusively restricted to the specific narrow period during immature stages of new neurons (7-10 days after birth). Furthermore, the pharmacological blockade of LTP induction suppressed the enhancement of cell survival by the HFS. These results suggest that the LTP induction within a narrow critical period of immature stages enhances the survival of newly generated neurons in rat DG

Successful radical resection of a leiomyosarcoma of the pulmonary trunk

AbstractJ Thorac Cardiovasc Surg 2001;122:1039-4

Sacral Stress Fracture following the Bone Union of Lumbar Spondylolysis

While 22 articles have reported on sacral stress fractures, it is a rare injury and its etiology is not well known. We present the case of a 16-year-old male who presented with low back pain in 2015. He was a high school soccer player with a previous history of a bilateral L5 lumbar spondylolysis in 2014. The patient refrained from soccer and wore a brace for six months. Two months after restarting soccer, he again complained of low back pain. After 1 year, a lumbar spine computed tomography revealed the bone union of the spondylolysis. At his first visit to our hospital, his general and neurological conditions were normal and laboratory data were within the normal range. Sacral coronal magnetic resonance imaging (MRI) of the left sacral ala revealed an oblique lineal signal void surrounding bone marrow edema. Based on his symptoms, sports history, and MRI, he was diagnosed with a sacral stress fracture. He again refrained from soccer; his low back pain soon improved, and, after 1 year, the abnormal signal change had disappeared on sacral MRI. Recurrent low back pain case caused by a sacral stress fracture occurring after the bone union of lumbar spondylolysis is uncommon