Energy bands in antiferromagnets are supposed to be spin degenerate in the absence of spin–orbit coupling (SOC). Recent studies have identified formal symmetry conditions for antiferromagnetic ...crystals in which this degeneracy can be lifted, spin splitting,even in the vanishing SOC (i.e., non‐relativistic) limit. Materials having such symmetries could enable spin‐split antiferromagnetic spintronics without the burden of using heavy‐atom compounds. However, the symmetry conditions that involve spin and magnetic symmetry are not always effective as practical material selection filters. Furthermore, these symmetry conditions do not readily disclose trends in the magnitude and momentum dependence of the spin‐splitting energy. Here, it is shown that the formal symmetry conditions enabling spin‐split antiferromagnets can be interpreted in terms of local motif pairs, such as octahedra or tetrahedra, each carrying opposite magnetic moments. Collinear antiferromagnets with such a spin‐structure motif pair, whose components interconvert by neither translation nor spatial inversion, will show spin splitting. Such a real‐space motif‐based approach enables an easy way to identify and design materials (illustrated in real example materials) having spin splitting without the need for SOC, and offers insights into the momentum dependence and magnitude of the spin splitting.
Energy bands in antiferromagnets with compensated magnetization are expected to maintain spin degeneracy without spin–orbit coupling (SOC). In this work, collinear antiferromagnets with a spin‐structure motif pair are shown,whose components cannot be interconverted by certain spatial transformation; these will show spin splitting. Such a motif‐based rule allows easy discerning of spin‐split antiferromagnets from conventional spin‐degenerate antiferromagnets.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Previous studies suggest that prone positioning (PP) can increase PaO
/FiO
and reduce mortality in moderate to severe acute respiratory distress syndrome (ARDS). The aim of our study was to determine ...whether the early use of PP combined with non-invasive ventilation (NIV) or high-flow nasal cannula (HFNC) can avoid the need for intubation in moderate to severe ARDS patients.
This prospective observational cohort study was performed in two teaching hospitals. Non-intubated moderate to severe ARDS patients were included and were placed in PP with NIV or with HFNC. The efficacy in improving oxygenation with four support methods-HFNC, HFNC+PP, NIV, NIV+PP-were evaluated by blood gas analysis. The primary outcome was the rate of intubation.
Between January 2018 and April 2019, 20 ARDS patients were enrolled. The main causes of ARDS were pneumonia due to influenza (9 cases, 45%) and other viruses (2 cases, 10%). Ten cases were moderate ARDS and 10 cases were severe. Eleven patients avoided intubation (success group), and 9 patients were intubated (failure group). All 7 patients with a PaO
/FiO
< 100 mmHg on NIV required intubation. PaO
/FiO
in HFNC+PP were significantly higher in the success group than in the failure group (125 ± 41 mmHg vs 119 ± 19 mmHg, P = 0.043). PaO
/FiO
demonstrated an upward trend in patients with all four support strategies: HFNC < HFNC+PP ≤ NIV < NIV+PP. The average duration for PP was 2 h twice daily.
Early application of PP with HFNC, especially in patients with moderate ARDS and baseline SpO
> 95%, may help avoid intubation. The PP was well tolerated, and the efficacy on PaO
/FiO
of the four support strategies was HFNC < HFNC+PP ≤ NIV < NIV+PP. Severe ARDS patients were not appropriate candidates for HFNC/NIV+PP.
ChiCTR, ChiCTR1900023564. Registered 1 June 2019 (retrospectively registered).
•The concepts of energy harvesting from flow-induced vibrations are classified.•The methods and principles of flow-induced vibrations energy harvesting are summarized.•The application of energy ...capture devices and commercially available devices are discussed.•The prospects of the research and application of flow-induced vibrations energy harvesting are presented.
In this paper, the currently popular flow-induced vibrations energy harvesting technologies are reviewed, including numerical and experimental endeavors, and some existing or proposed energy capture concepts and devices are discussed. The energy harvesting mechanism and current research progress of four types of flow-induced vibrations, such as vortex-induced vibrations, galloping, flutter and buffeting, are introduced. To enhance the performance of the harvesters and broaden the operating range, the researchers have proposed various mechanical designs, methods of the structures’ surfaces optimization and concepts with incorporated magnets for multistability. The paper summarizes the works led to the current wind energy and hydro energy harvesters based on the principle of flow-induced vibrations, including bladeless generator Vortex Bladeless, University of Michigan vortex-induced vibrations aquatic clean energy, Australian BPS company's airfoil tidal energy capture device bioSTREAM, and others. This shows the gradual progress and maturity of the flow-induced vibrations energy harvesters. The article concludes with a discussion on the current problems in the area of the flow-induced vibration energy capture and the challenges faced.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In order to better constrain the evolution of the Tethyan orogenic system, we conducted an integrated investigation involving U-Pb dating of igneous and detrital zircon, geochemical analysis of ...igneous rocks, compositional analysis of sedimentary strata, and a synthesis of existing work across the Qilian Shan, Qaidam Basin, and the Eastern Kunlun Range of central and northern Tibet. This effort reveals five stages of arc magmatism at 1005-910 Ma, 790-720 Ma, 580-500 Ma, 490-375 Ma, and 290-195 Ma, respectively. Arc activities were interrupted by repeated continent-continent collision followed by ocean opening along the older suture zones first created in the Neoproterozoic. This suggests that Wilson cycles have played a controlling role in constructing the southern Asian continent. The magmatic history and regional geologic constraints allow us to construct a coherent tectonic model that has the following key features. (1) The linked South Qilian suture in the west and North Qinling suture in the east formed the northern boundary of the coherent Kunlun-Qaidam-North Qinling Terrane in the early Paleozoic. (2) The Songpan-Ganzi Terrane has been the western part of the Yangtze craton since the Neoproterozoic. (3) Development of the wide (>700 km) Permian-Triassic arc across the Kunlun-Qaidam Terrane was induced by flat subduction and rapid slab rollback, which also caused extreme extension of the Songpan-Ganzi Terrane. (4) The formation of the Anymaqen-Kunlun-Muztagh Ocean (= the Neo-Kunlun Ocean in this study) was created within Laurasia rather than being a preexisting ocean between Gondwana and Laurasia as postulated by most early studies.
The bed nucleus of stria terminalis (BST) is a critical structure that mediates sustained vigilant responses to contextual, diffuse, and unpredictable threats. Dysfunction of the BST could lead to ...excessive anxiety and hypervigilance, which are often observed in posttraumatic stress disorder and anxiety disorders. Vigilance of potential future threats from the external environment is a basic brain function and probably requires rapid and/or short neural circuits, which enable both quick detection of the potential threats and fast adaptive responses. However, the BST in literature does not appear to receive spatial information directly from earlier visual or spatial processing structures. In this study, a novel subdivision of the BST is uncovered in monkey, rat, and mouse brains based on the human equivalent and is found in mouse to receive direct inputs from the ventral lateral geniculate nucleus and pretectal nucleus as well as from the spatial processing structures such as subiculum, presubiculum, and medial entorhinal cortex. This new subdivision, termed spindle‐shaped small cell subdivision (BSTsc), is located between the known BST and the anterior thalamus. In addition to the unique afferent connections and cell morphology, the BSTsc also displays unique molecular signature (e.g., positive for excitatory markers) compared with other BST subdivisions, which are mostly composed of inhibitory GABAergic neurons. The BSTsc appears to have largely overlapping efferent projections with other BST subdivisions such as the projections to the amygdala, hypothalamus, nucleus accumbens, septum, and brainstem. Together, the present study suggests that the BSTsc is poised to serve as a shortcut bridge directly linking spatial information from the environment to vigilant adaptive internal responses.
A novel subdivision of the bed nucleus of stria terminalis (BST) was identified in monkey, rat, and mouse brains based on the human equivalent. This spindle‐shaped small cell subdivision (BSTsc) receives its main inputs from the earlier visual and spatial processing structures and projects to many common target regions as other BST subdivisions do (see the graph). The neurons in the BSTsc mostly expresses excitatory marker genes while those in other BST components mainly contains inhibitory marker genes. The BSTsc is poised to serve as a shortcut bridge directly linking spatial information from the environment to vigilant adaptive internal responses.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
