Robust encoding of natural stimuli by neuronal response sequences in monkey visual cortex.

Parallel multisite recordings in the visual cortex of trained monkeys revealed that the responses of spatially distributed neurons to natural scenes are ordered in sequences. The rank order of these sequences is stimulus-specific and maintained even if the absolute timing of the responses is modified by manipulating stimulus parameters. The stimulus specificity of these sequences was highest when they were evoked by natural stimuli and deteriorated for stimulus versions in which certain statistical regularities were removed. This suggests that the response sequences result from a matching operation between sensory evidence and priors stored in the cortical network. Decoders trained on sequence order performed as well as decoders trained on rate vectors but the former could decode stimulus identity from considerably shorter response intervals than the latter. A simulated recurrent network reproduced similarly structured stimulus-specific response sequences, particularly once it was familiarized with the stimuli through non-supervised Hebbian learning. We propose that recurrent processing transforms signals from stationary visual scenes into sequential responses whose rank order is the result of a Bayesian matching operation. If this temporal code were used by the visual system it would allow for ultrafast processing of visual scenes.

Effect and mechanism of matrine on steatosis Chang Liver cells induced by oleic acid / 中国药房

OBJECTIVE To investigate the effects of matrine （MT） on steatosis Chang Liver cell model induced by oleic acid （OA） and its possible mechanism. METHODS Chang Liver cells were divided into blank group， model group and MT low-dose， medium-dose group and high-dose groups （0.1， 0.5， 1.0 mmol/L）. Except for blank group， the other groups were treated with 1.0 mmol/L OA for 24 h to establish steatosis model， and MT groups were given corresponding concentrations of drugs for 24 h. The activities of steatosis Chang Liver cells were observed； the morphologies of intracellular lipid droplets were observed and lipid content was also determined. The contents of liver function indexes [alanine transaminase （ALT）， aspartate transaminase （AST）， total bilirubin （TBIL）， alkaline phosphatase （ALP）]， as well as mRNA and protein expressions of farnesoid X receptor （FXR）， cytochrome P450 7A1 （CYP7A1） and fibroblast growth factor 19 （FGF19） were all detected. RESULTS OA and MT had no significant effect on the activity of Chang Liver cells. After OA treatment， orange lipid droplets formed in cytoplasm； compared with blank group， relative lipid content and the levels of liver function indexes were increased significantly， while the mRNA and protein expressions of FXR， CYP7A1 and FGF19 were down-regulated significantly （P＜0.05）. After treatment of low， medium and high concentrations of MT， above indexes were all reversed significantly （P＜0.05）. CONCLUSIONS MT could significantly improve the lipid content and liver function indexes of steatosis Chang Liver cells induced by OA though regulating FXR/CYP7A1/ FGF19 signaling pathway.

Role of phosphorus in Vallisneria natans and biofilm exposure to Pb2+ and Cd2+ stress.

Phosphorus (P) could improve the stress resistance and adaptability of submerged macrophytes. This study investigated the physiological and biochemical responses of plants exposed to different P and Pb, Cd concentrations. Alterations of protein synthesis, the DNA methylation (5-mC) level, and the microbial community of biofilm were also evaluated. Results indicated that lower P (0.5 mg·L-1) could promote plant growth and metal enrichment while mitigating the toxicity of metals. Higher P (5.0 mg·L-1) induced a degree of oxidative stress, as confirmed by increased activity of superoxide dismutase, peroxidase, and acid phosphatase, as well as increased malondialdehyde contents. While the variation of metallothionein synthesis and DNA methylation level of the plant was dependent on the level of P and metals in the water. These responses indicated potential mechanisms of P detoxification and intoxication. In addition, more abundant microbial communities were observed in biofilms exposed to P and metals. These findings provide theoretical support for the metal detoxification of P in submerged plants.

Role of 1'-Ribose Cyano Substitution for Remdesivir to Effectively Inhibit both Nucleotide Addition and Proofreading in SARS-CoV-2 Viral RNA Replication

COVID-19 has recently caused a global health crisis and an effective interventional therapy is urgently needed. SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) is a promising but challenging drug target due to its intrinsic proofreading exoribonuclease (ExoN). Remdesivir targeting SARS-CoV-2 RdRp exerts high drug efficacy in vitro and in vivo. However, its underlying inhibitory mechanisms remain elusive. Here, we performed all-atom molecular dynamics simulations with an accumulated simulation time of 24 microseconds to elucidate the molecular mechanisms underlying the inhibitory effects of Remdesivir. We found that Remdesivirs 1-cyano group of possesses the dual role of inhibiting nucleotide addition and proofreading. The presence of its polar 1-cyano group at an upstream site in RdRp causes instability and hampers RdRp translocation. This leads to a delayed chain termination of RNA extension, which may also subsequently reduce the likelihood for Remdesivir to be cleaved by ExoN acting on the 3-terminal nucleotide. In addition, our simulations suggest that Remdesivirs 1-cyano group can also disrupt the cleavage active site of ExoN via steric interactions, leading to a further reduced cleavage efficiency. Our work provides plausible molecular mechanisms on how Remdesivir inhibits viral RNA replication and may guide rational design for new treatments of COVID-19 targeting viral replication.

Medical Staff's Cognition on Clinical Pharmaceutical Care / 中国药房

OBJECTIVE:To investigate the cognition of medical staff's cognition on clinical pharmaceutical care.METHODS:A total of 105 questionnaires collected from the doctors and nurses were subjected to an aggregate analysis in terms of their ultimate educational background,professional title,working lifetime,cognition on clinical pharmaceutical care etc.RESULTS & CONCLUSIONS:Doctors and nurses had positive attitude toward clinical pharmacy care and it is greatly demanded in drug use.Clinical pharmaceutical staff should keep improving their expertise level and strengthen cooperation with medical staff so as to facilitate the development of clinical pharmaceutical care.