Continuous,efficient and safe synthesis of 1-oxa-2-azaspiro[2.5]octane in a microreaction system

1-Oxa-2-azaspiro[2.5]octane,as one of N-H oxaziridines,is a selective electrophilic aminating agent for N-,S-,C-,and O-nucleophiles.It has the features of stereoselectivity and the absence of formation of strongly acidic or basic byproducts,leading to considerable interest in the development of organic synthetic methods.Currently,the economically feasible route of production of 1-oxa-2-azaspiro[2.5]octane is the reaction of cyclohexanone with ammonia and sodium hypochlorite.However,due to strong exothermic reactions,massive gas release and heterogeneous reaction,the controllability,efficiency and safety of the reaction are in great difficulty using batch technology.In this paper,a microreaction system containing predispersion,reaction and phase separation was introduced into the preparation of 1-oxa-2-azaspiro[2.5]octane.The research results showed that precise control of the process including droplet dispersion,temperature control,reaction time control and fast continuous phase separation,was the key to process intensification.Under optimal conditions,the concentration of 1-oxa-2-azaspiro[2.5]octane in product obtained by microreaciton system(~2.0 mol·L^(-1))was much higher than that obtained by batch technology(0.2-0.4 mol·L^(-1)),which demonstrated that the continuous-flow synthesis would be a more efficient substitute for batch synthesis.Meanwhile,the results of the derivation experiments also showed that the aminating agent solution with higher concentration was more advantageous in the applications.

Cloning and Bioinformatics Analysis of the GlROP6 gene in Glehnia littoralis

Rho-related GTPase from plants(ROP)proteins play an essential role in plant stress resistance.In this study,the full-length GlROP6 gene was cloned based on G.littoralis transcriptome sequencing data acquired in response to salt stress.The protein sequence,conserved domains,secondary structure,three-dimensional structure,phylogenetic relationships,and expression pattern of the GlROP6 gene were systematically analysed.Our results showed that the full-length GlROP6 gene had an open reading frame of 606 bp,which encoded 201 amino acid residues with a relative molecular weight of 22.23463 kDa and a theoretical isoelectric point of 9.06.Amino acid sequence analyses indicated that the structure of the GlROP6 protein was conserved,and included five G-box motifs(G1–G5),an effector binding region,a Rho insert region and a C-terminal hypervariable region.According to our phylogenetic analysis,the GlROP6 protein was closely related to the ROP protein of Daucus carota subsp.Sativus.Our quantitative real-time PCR results revealed that GlROP6 was highly expressed in flower,and GlROP6 expression was significantly upregulated in G.littoralis roots treated with NaCl.This study will facilitate investigations into the function of GlROP genes in response to salt stress in G.littoralis.

Optimization of Polysaccharide Extraction from Radix Glehniae Root Bark by Response Surface Methodology and Anti-immunosuppressive Activity Analysis

[ Objective ] This study aimed to establish and optimize the extraction technology of polysaccharides from Radix Glehniae root bark, and to explore the processing methods of Radix Glehniae in producing areas. [ Method ] Based on the single-factor experiment, with polysaccharide content and polysaccharide yield as indices, various factors affecting polysaccharide yield from Radix Glehniae root bark were investigated by central composite design-response surface method. Mo- reover, immune functions of cyclophosphamide-induced blood-deficient mice in various polysaccharide groups were compared to investigate the effects of root bark removal of Radix Glehniae on medicinal quality. [ Result] Ultrasonic extraction was the appropriate extraction technology of polysaccharides from Radix Glehniae root bark. The optimal ultrasonic extraction conditions were ultrasonic time 36 min, ultrasonic power 460 W, solid-liquid ratio 1： 10, ethanol concentration 80%, under which polysaccharide yield reached 16.08%. Polysaccharides extracted from Radix Glehniae root （ALP） and Radix Glehniae root bark （BLP） could effec- tively improve immune function of blood-deficient mice with no significant differences. [ Conclusion] Radix Glehniae could be used without removal of root bark. The optimized extraction process was stable and feasible, which laid a solid foundation for further comprehensive development and utilization of Radix Glehniae root bark.

Influence of soil to structure stiffness on the accuracy of the pushover method for underground structures

The pushover method for underground structures is a seismic analysis method featured by high calculation accuracy and a simple implementation process.The method has been widely used in seismic design and other related scientific research;however,the influence of different soil-structure flexibility ratios on the accuracy of this method is still not well understood.In this study,we select the cross-section structures beneath the Daikai subway station as the research object and establish 12 finite element analysis models with different soil-structure flexibility ratios using ABAQUS.All models are computed by the dynamic time-history method or the pushover method.Furthermore,the dynamic time-history solution result is taken as the standard solution,and the precision and application of the pushover analysis method are discussed based on the parameters of peak interlayer displacement and peak internal force of the middle column section.The results show that the soil-structure flexibility ratio has a significant influence on the calculation accuracy of the pushover method,and the calculation accuracy of this method is the most ideal when the soil-structure flexibility is equal to 1.The research results can provide significant references for the seismic design of underground structures or the improvement of simplified seismic analysis methods.

综合化学实验模块化教学的尝试——以钛铁矿的综合利用为例

将综合实验"钛铁矿的综合利用"划分成若干个模块,并留有扩展的空间,可根据专业不同、教学层次不同和实验时间长短的不同自由选择其中的模块,达到各自特色的教学目的。

Analysis of As₂S₃-Ti: LiNbO₃Taper Couplers Using Supermode Theory

In this work, we develop a simulation method based on supermode theory and transfer matrix formalism, and then apply it to the analysis and design of taper couplers for vertically integrated As2S3 and Ti: LiNbO3 hybrid waveguides. Test structures based on taper couplers are fabricated and characterized. The experimental results confirm the validity of the modeling method, which in turn, is used to analyze the fabricated couplers.

Abnormal intra-network architecture in extra-striate cortices in amblyopia: a resting state fMRI study

Background:Amblyopia(lazy eye)is one of the most common causes of monocular visual impairment.Intensive investigation has shown that amblyopes suffer from a range of deficits not only in the primary visual cortex but also the extra-striate visual cortex.However,amblyopic brain processing deficits in large-scale information networks especially in the visual network remain unclear.Methods:Through resting state functional magnetic resonance imaging(rs-fMRI),we studied the functional connectivity and efficiency of the brain visual processing networks in 18 anisometropic amblyopic patients and 18 healthy controls(HCs).Results:We found a loss of functional correlation within the higher visual network(HVN)and the visuospatial network(VSN)in amblyopes.Additionally,compared with HCs,amblyopic patients exhibited disruptions in local efficiency in the V3v(third visual cortex,ventral part)and V4(fourth visual cortex)of the HVN,as well as in the PFt,hIP3(human intraparietal area 3),and BA7p(Brodmann area 7 posterior)of the VSN.No significant alterations were found in the primary visual network(PVN).Conclusion:Our results indicate that amblyopia results in an intrinsic decrease of both network functional correlations and local efficiencies in the extra-striate visual networks.