Abstract
We report experimental observation of large anomalous Hall effect exhibited in non-collinear triangular antiferromagnet D0
19
-type Mn
3
Ga with coplanar spin structure at temperatures ...higher than 100 K. The value of anomalous Hall resistivity increases with increasing temperature, which reaches 1.25 μΩ · cm at a low field of ~300 Oe at room temperature. The corresponding room-temperature anomalous Hall conductivity is about 17 (Ω · cm)
−1
. Most interestingly, as temperature falls below 100 K, a temperature-independent topological-like Hall effect was observed. The maximum peak value of topological Hall resistivity is about 0.255 μΩ · cm. The appearance of the topological Hall effect is attributed to the change of spin texture as a result of weak structural distortion from hexagonal to orthorhombic symmetry in Mn
3
Ga. Present study suggests that Mn
3
Ga shows promising possibility to be antiferromagnetic spintronics or topological Hall effect-based data storage devices.
Striatal spiny projection neurons (SPNs) receive convergent excitatory synaptic inputs from the cortex and thalamus. Activation of spatially clustered and temporally synchronized excitatory inputs at ...the distal dendrites could trigger plateau potentials in SPNs. Such supralinear synaptic integration is crucial for dendritic computation. However, how plateau potentials interact with subsequent excitatory and inhibitory synaptic inputs remains unknown. By combining computational simulation, two-photon imaging, optogenetics, and dual-color uncaging of glutamate and GABA, we demonstrate that plateau potentials can broaden the spatiotemporal window for integrating excitatory inputs and promote spiking. The temporal window of spiking can be delicately controlled by GABAergic inhibition in a cell-type–specific manner. This subtle inhibitory control of plateau potential depends on the location and kinetics of the GABAergic inputs and is achieved by the balance between relief and reestablishment of NMDA receptor Mg2+ block. These findings represent a mechanism for controlling spatiotemporal synaptic integration in SPNs.
Two-photon laser scanning microscopy (2PLSM) has allowed unprecedented fluorescence imaging of neuronal structure and function within neural tissue. However, the resolution of this approach is poor ...compared to that of conventional confocal microscopy. Here, we demonstrate supraresolution 2PLSM within brain slices. Imaging beyond the diffraction limit is accomplished by using near-infrared (NIR) lasers for both pulsed two-photon excitation and continuous wave stimulated emission depletion (STED). Furthermore, we demonstrate that Alexa Fluor 594, a bright fluorophore commonly used for both live cell and fixed tissue fluorescence imaging, is suitable for STED 2PLSM. STED 2PLSM supraresolution microscopy achieves approximately 3-fold improvement in resolution in the radial direction over conventional 2PLSM, revealing greater detail in the structure of dendritic spines located ∼100 microns below the surface of brain slices. Further improvements in resolution are theoretically achievable, suggesting that STED 2PLSM will permit nanoscale imaging of neuronal structures located in relatively intact brain tissue.
•A homemade interferometric uniaxial inertial sensor is developed.•Tilt-vertical coupling of the sensor is studied.•The potential for active seismic isolation is experimentally examined.
The goal of ...this study is to demonstrate the capability to actively isolate a platform from seismic vibrations using an interferometric inertial sensor. To this purpose, a homemade high-resolution interferometric uni-axial inertial sensor (in the vertical direction) is developed and then integrated to a single-degree-of-freedom (SDOF) seismic isolation system. A theoretical study is firstly performed in order to better understand the dynamics of the system. It is found that the sensor suffers from a tilt-vertical coupling due to the influence of the gravity force if the sensor is not perfectly aligned. By taking this tilt coupling into account, a dedicated controller is designed, seeking a large vibration isolation in the frequency band of interest. Experiments are then conducted for validating the theoretical analysis and examining the vibration isolation performance. It shows a reduction of the transmitted motion of up to 60 dB in a frequency range from 0.1 Hz to 10 Hz.
Highlights ► This review focuses on the effects of ACh through muscarinic receptors in striatum. ► ACh inhibits excitatory synaptic transmission through presynaptic M2 muscarinic receptors. ► ACh ...enhances dendritic excitability in MSNs by inhibiting potassium channels.
Knee osteoarthritis is a degenerative arthritis that mainly affects older adults. Over time, osteoarthritis can result in significant and sustained discomfort, pain, and disability. Current treatment ...focuses on the alleviation of pain and functional impairment. While arthroplasty is the definitive management option, it subjects patients to surgical complications, and the possibility of surgical revisions. In addition, many patients are not surgical candidates. Instead, pharmacological therapy is recommended first-line for most patients. On top of pharmacological therapy, there are a range of non-operative procedural options available. However, leading professional guidelines vary in their recommendations for these agents.
Therefore, we present a review of recent randomized controlled trials and meta-analyses on injectable corticosteroids, hyaluronic acid (HA), platelet-rich plasma (PRP), mesenchymal stem cell injections, and ozone therapy. The preliminary data reveal the strongest evidence in favour of corticosteroid injections, although there are promising findings regarding the long-term efficacy of HA and PRP.
The proper formation of synaptic connectivity in the mammalian brain is critical for complex behavior. In the striatum, balanced excitatory synaptic transmission from multiple sources onto two ...classes of principal neurons is required for coordinated and voluntary motor control. Here we show that the interaction between the secreted semaphorin 3E (Sema3E) and its receptor Plexin-D1 is a critical determinant of synaptic specificity in cortico-thalamo-striatal circuits in mice. We find that Sema3e (encoding Sema3E) is highly expressed in thalamostriatal projection neurons, whereas in the striatum Plxnd1 (encoding Plexin-D1) is selectively expressed in direct-pathway medium spiny neurons (MSNs). Despite physical intermingling of the MSNs, genetic ablation of Plxnd1 or Sema3e results in functional and anatomical rearrangement of thalamostriatal synapses specifically in direct-pathway MSNs without effects on corticostriatal synapses. Thus, our results demonstrate that Sema3E and Plexin-D1 specify the degree of glutamatergic connectivity between a specific source and target in the complex circuitry of the basal ganglia.
Action control is a key brain function determining the survival of animals in their environment. In mammals, neurons expressing dopamine D2 receptors (D2R) in the dorsal striatum (DS) and the nucleus ...accumbens (Acb) jointly but differentially contribute to the fine regulation of movement. However, their region-specific molecular features are presently unknown. By combining RNAseq of striatal D2R neurons and histological analyses, we identified hundreds of novel region-specific molecular markers, which may serve as tools to target selective subpopulations. As a proof of concept, we characterized the molecular identity of a subcircuit defined by WFS1 neurons and evaluated multiple behavioral tasks after its temporally-controlled deletion of D2R. Consequently, conditional D2R knockout mice displayed a significant reduction in digging behavior and an exacerbated hyperlocomotor response to amphetamine. Thus, targeted molecular analyses reveal an unforeseen heterogeneity in D2R-expressing striatal neuronal populations, underlying specific D2R's functional features in the control of specific motor behaviors.
Tension stimulation is an important inducer of endplate cartilage degeneration, but the specific regulatory mechanism remains unclear. This study was the first to reveal the mechanism by which ...methyltransferase-like 3 (METTL3)-mediated N(6)-methyladenosine (m6A) modification affected the extracellular matrix anabolism by tension-induced endplate chondrocytes.
We examined the differences in METTL3 expression and m6A methylation levels in human endplate chondrocytes and human cartilage endplate tissues under in vitro tension. The effect on endplate cartilage degeneration was evaluated by manipulating m6A methylation mediated by METTL3 in vivo and in vitro. The effect of METTL3-mediated m6A methylation on the stability of sex-determining region Y-box transcription factor 9 (SOX9) gene expression was determined experimentally.
METTL3 expression and m6A methylation levels were significantly increased in degenerative human endplate cartilage tissue. Similarly, tension stimulation inhibited the ability of human endplate chondrocytes to synthesize extracellular matrix, which was accompanied by an increase in METTL3-mediated m6A methylation. The ability of endplate chondrocytes to resist tension was significantly enhanced by inhibiting METTL3 expression and subsequently downregulating m6A methylation in vitro and in vivo, thereby reducing intervertebral disc degeneration. Furthermore, METTL3 mediated SOX9 RNA methylation and disrupted SOX9 mRNA stability, thereby inhibiting the gene expression of the downstream collagen type II alpha 1 chain.
Tension stimulation downregulated SOX9 expression through METTL3-mediated m6A methylation, thereby inhibiting the synthesis of extracellular matrix in endplate chondrocytes.
•Sex hormones modify auditory processing to facilitate mating.•Hormonal level changes with age can influence age-related hearing loss.•Prospective studies reveal that hormone therapies can alter ...hearing abilities.•Combining hormones with other supplements may be a key for future therapies.•Co-morbid medical conditions can have a negative impact on hearing in the elderly.
Provocative research has revealed both positive and negative effects of hormones on hearing as we age; with in some cases, mis-regulation of hormonal levels in instances of medical comorbidities linked to aging, lying at the heart of the problem. Animal model studies have discovered that hormonal fluctuations can sharpen hearing for improved communication and processing of mating calls during reproductive seasons. Sex hormones sometimes have positive effects on auditory processing, as is often the case with estrogen, whereas combinations of estrogen and progesterone, and testosterone, can have negative effects on hearing abilities, particularly in aging subjects. Too much or too little of some hormones can be detrimental, as is the case for aldosterone and thyroid hormones, which generally decline in older individuals. Too little insulin, as in Type 1 diabetics, or poor regulation of insulin, as in Type 2 diabetics, is also harmful to hearing in our aged population. In terms of clinical translational possibilities, hormone therapies can be problematic due to systemic side effects, as has happened for estrogen/progestin combination hormone replacement therapy (HRT) in older women, where the HRT induces a hearing loss. As hormone therapy approaches are further developed, it may be possible to lower needed doses of hormones by combining them with supplements, such as antioxidants. Another option will be to take advantage of emerging technologies for local drug delivery to the inner ear, including biodegradeable, sustained-release hydrogels and micro-pumps which can be implanted in the middle ear near the round window. In closing, exciting research completed to date, summarized in the present report bodes well for emerging biomedical therapies to prevent or treat age-related hearing loss utilizing hormonal strategies.
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