44 research outputs found
The volatile anesthetic isoflurane differentially inhibits voltage-gated sodium channel currents between pyramidal and parvalbumin neurons in the prefrontal cortex
BackgroundHow volatile anesthetics work remains poorly understood. Modulations of synaptic neurotransmission are the direct cellular mechanisms of volatile anesthetics in the central nervous system. Volatile anesthetics such as isoflurane may reduce neuronal interaction by differentially inhibiting neurotransmission between GABAergic and glutamatergic synapses. Presynaptic voltage-dependent sodium channels (Nav), which are strictly coupled with synaptic vesicle exocytosis, are inhibited by volatile anesthetics and may contribute to the selectivity of isoflurane between GABAergic and glutamatergic synapses. However, it is still unknown how isoflurane at clinical concentrations differentially modulates Nav currents between excitatory and inhibitory neurons at the tissue level.MethodsIn this study, an electrophysiological recording was applied in cortex slices to investigate the effects of isoflurane on Nav between parvalbumin (PV+) and pyramidal neurons in PV-cre-tdTomato and/or vglut2-cre-tdTomato mice.ResultsIsoflurane at clinically relevant concentrations produced a hyperpolarizing shift in the voltage-dependent inactivation and slowed the recovery time from the fast inactivation in both cellular subtypes. Since the voltage of half-maximal inactivation was significantly depolarized in PV+ neurons compared to that of pyramidal neurons, isoflurane inhibited the peak Nav currents in pyramidal neurons more potently than those of PV+ neurons (35.95 ± 13.32% vs. 19.24 ± 16.04%, P = 0.036 by the Mann-Whitney test).ConclusionsIsoflurane differentially inhibits Nav currents between pyramidal and PV+ neurons in the prefrontal cortex, which may contribute to the preferential suppression of glutamate release over GABA release, resulting in the net depression of excitatory-inhibitory circuits in the prefrontal cortex
The level effect and volatility effect of uncertainty shocks in China
Previous studies have assumed that the volatility of exogenous
shocks is constant, which can only measure the level effects of
uncertain shocks. This article introduces the time-varying volatility
model into a Dynamic Stochastic General Equilibrium (D.S.G.E.)
model and uses the third-order perturbation method to identify
and decompose the level and volatility effects of uncertainty
shocks. Based on the results of empirical research in China, the
effect of volatility shocks is different from that of level shocks: the
effect of level shocks is direct and positive, and its impact is
larger, while the effect of volatility shocks is indirect and negative,
and its impact is smaller. This article also finds that the impact of
uncertainty shocks will lead to economic stagnation, inflation, and
the stagflation effect
Microbial traits determine soil C emission in response to fresh carbon inputs in forests across biomes
Soil priming is a microbial-driven process, which determines key soil–climate feedbacks in response to fresh carbon inputs. Despite its importance, the microbial traits behind this process are largely undetermined. Knowledge of the role of these traits is integral to advance our understanding of how soil microbes regulate carbon (C) emissions in forests, which support the largest soil carbon stocks globally. Using metagenomic sequencing and C-glucose, we provide unprecedented evidence that microbial traits explain a unique portion of the variation in soil priming across forest biomes from tropical to cold temperature regions. We show that microbial functional profiles associated with the degradation of labile C, especially rapid simple sugar metabolism, drive soil priming in different forests. Genes involved in the degradation of lignin and aromatic compounds were negatively associated with priming effects in temperate forests, whereas the highest level of soil priming was associated with β-glucosidase genes in tropical/subtropical forests. Moreover, we reconstructed, for the first time, 42 whole bacterial genomes associated with the soil priming effect and found that these organisms support important gene machinery involved in priming effect. Collectively, our work demonstrates the importance of microbial traits to explain soil priming across forest biomes and suggests that rapid carbon metabolism is responsible for priming effects in forests. This knowledge is important because it advances our understanding on the microbial mechanisms mediating soil–climate feedbacks at a continental scale.This work were financially supported by the National Natural Science Foundation of China (41907031), the Chinese Academy of Sciences “Light of West China” Program for Introduced Talent in the West, the National Natural Science Foundation of China (31570440, 31270484), the Key International Scientific and Technological Cooperation and Exchange Project of Shaanxi Province, China (2020KWZ-010), the 2021 First Funds for Central Government to Guide Local Science and Technology Development in Qinghai Province (2021ZY002), the i-LINK +2018 (LINKA20069) from CSIC, and a Ramón y Cajal grant from the Spanish Ministry of Science and Innovation (RYC2018-025483-I
Two types of zero Hall phenomena in few-layer MnBiTe
The van der Waals antiferromagnetic topological insulator MnBiTe
represents a promising platform for exploring the layer-dependent magnetism and
topological states of matter. Despite the realization of several quantized
phenomena, such as the quantum anomalous Hall effect and the axion insulator
state, the recently observed discrepancies between magnetic and transport
properties have aroused controversies concerning the topological nature of
MnBiTe in the ground state. Here, we demonstrate the existence of two
distinct types of zero Hall phenomena in few-layer MnBiTe. In addition
to the robust zero Hall plateau associated with the axion insulator state, an
unexpected zero Hall phenomenon also occurs in some odd-number-septuple layer
devices. Importantly, a statistical survey of the optical contrast in more than
200 MnBiTe reveals that such accidental zero Hall phenomenon arises
from the reduction of effective thickness during fabrication process, a factor
that was rarely noticed in previous studies of 2D materials. Our finding not
only resolves the controversies on the relation between magnetism and anomalous
Hall effect in MnBiTe, but also highlights the critical issues
concerning the fabrication and characterization of devices based on 2D
materials.Comment: 21 pages, 4 figure
Dual function filtration and catalytic breakdown of organic pollutants in wastewater using ozonation with titania and alumina membranes
Water recycling via treatment from industrial and/or municipal waste sources is one of the key strategies
for resolving water shortages worldwide. Polymer membranes are effective at improving the water quality
essential for recycling, but depend on regular cleaning and replacement. Pure ceramic membranes
can reduce the cleaning need and last significantly longer in the same applications while possessing the
possibility of operating in more aggressive environments not suitable for polymers. In the current work,
filtration using a tubular ceramic membrane (�-Al2O3 or TiO2) was combined with ozonation to remove
organic compounds present in a secondary effluent to enhance key quality features of the water (colour
and total organic carbon, TOC) for its potential reuse.
‘Bare’ commercial �-Al2O3 filters (pore size
∼0.58 �m) were tested as a microfiltration membrane and
compared with the more advanced catalytically active TiO2 layer that was formed by the sol–gel method.
The presence of anatase with a 4 nm pore size at the membrane surface was confirmed by X-ray diffraction
(XRD) and N2 adsorption. Filtration of the effluent over a 2 h period led to a reduction in flux to 45% and
60% of the initial values for the �-alumina and TiO2 membrane, respectively. However, a brief dose (2 min)
of ozone at the start of the run resulted in reductions to only 70% of the initial flux for both membranes. It
is likely that the oxide’s functional property facilitated the formation of hydroxyl (OH•) or other radicals
on the membrane surface from ozone decomposition which targeted the breakdown of organic foulants
thus inhibiting their deposition. Interestingly, the porous structure therefore acted in a synergistic, dual
function mode to physically separate the particulates while also catalytically breaking down organic
matter. The system also greatly improved the efficiency of membrane filtration for the reduction of
colour, A254 (organics absorption at the wavelength of 254 nm) and TOC. The best performance came
from combined ozonation (2 min ozonation time with an estimated applied ozone dose of 8 mg L−1)
with the TiO2 membrane, which was able to reduce colour by 88%, A254 by 75% and TOC by 43%. It is
clearly evident that a synergistic effect occurs with the process combination of ozonation and ceramic
membrane filtration demonstrating the practical benefit of combining ceramic membrane filtration with
conventional water ozonation
Detection of DNA hybridization using liquid crystal based whispering gallery mode microbubble
DNA detection based on DNA hybridization has wide applications in various fields, such as clinical diagnostics, food safety, and environmental monitoring, etc. At present, common DNA detection approaches include fluorescence-based microarray technique, electrochemical method and surface plasmon resonance (SPR), etc. However, these methods require additional precise equipments and relatively complicated detection process. In this work, we developed a biosensor platform based on a liquid crystal (LC)-amplified optofluidic whispering gallery mode (WGM) resonator to achieve ultra-sensitive, label-free, and quick-response DNA hybridization detection. Liquid crystal is a material with high sensitivity, rapid response, and low cost. It exhibits significant directional and positional ordering, and it is sensitive and responsive to external stimuli. LC molecules exhibit a uniform orientation on the surface of the resonator, when the surface is covered with an appropriate amount of ssDNA. Once complementary DNA and ssDNA hybridize on the surface, the homotropic orientation of the LCs will be destroyed. Due to the simultaneous interaction of the WGM and the LCs in the optofluidic resonator, changes caused by the DNA hybridization can be amplified, resulting in a shift in the resonance wavelength. In this experiment, we used the spectral wavelength shift as a sensing parameter to achieve the detection of target DNA, and a lower detection limit compared to traditional DNA detection methods was obtained. At the same time, this biosensor platform also shows good selectivity. Our research results suggest that the LC based WGM optical microcavity sensing platform can provide an ultra-sensitive, label free solution for DNA detection
Using Recursive Feature Selection with Random Forest to Improve Protein Structural Class Prediction for Low-Similarity Sequences
Many combinations of protein features are used to improve protein structural class prediction, but the information redundancy is often ignored. In order to select the important features with strong classification ability, we proposed a recursive feature selection with random forest to improve protein structural class prediction. We evaluated the proposed method with four experiments and compared it with the available competing prediction methods. The results indicate that the proposed feature selection method effectively improves the efficiency of protein structural class prediction. Only less than 5% features are used, but the prediction accuracy is improved by 4.6-13.3%. We further compared different protein features and found that the predicted secondary structural features achieve the best performance. This understanding can be used to design more powerful prediction methods for the protein structural class