The Infection Control Measures Taken in MRI Examination During the COVID-19 Pandemic Prevention and Control Period

Objective:To optimize the magnetic resonance imaging(MRI)detection process in view of the COVID-19 pandemic,standardize and strengthen the infection control and management MRI rooms.Methods:According to the Technical Guide for COVID-19 Prevention and Control in Medical Institutions(3rd Edition),with reference to the current COVID-19 infection control plan,there are three aspects involved in the planning of MRI examination:MRI room management,medical staff management and protection,and patient management,especially the use of full plastic nose strip medical masks.Infection prevention measures are formulated,scientific prevention and control are made,and accurate policies are implemented.Results:MRI examination was carried out according to the infection control and management of MRI room plan during the epidemic,so as to ensure the safety of examination,the safety of patients and the safety of medical staff and no cross infection in hospital.Conclusion:The implementation of proper infection prevention measures during MRI examination in light of COVID-19 ensures that patients wear medical surgical masks with full plastic nose strips throughout the process to avoid cross-infection,ensure the safety of doctors and patients,and maintain the health of the population.

Neuropeptide Y gene transfection inhibits post-epileptic hippocampal synaptic reconstruction

Exogenous neuropeptide Y has antiepileptic effects; however, the underlying mechanism and optimal administration method for neuropeptide Y are still unresolved. Previous studies have used intracerebroventricular injection of neuropeptide Y into animal models of epilepsy. In this study, a recombinant adeno-associated virus expression vector carrying the neuropeptide Y gene was injected into the lateral ventricle of rats, while the ipsilateral hippocampus was injected with kainic acid to establish the epileptic model. After transfection of neuropeptide Y gene, mossy fiber sprouting in the hippocampal CA3 region of epileptic rats was significantly suppressed, hippocampal synaptophysin （p38） mRNA and protein expression were inhibited, and epileptic seizures were reduced. These experimental findings indicate that a recombinant adeno-associated virus expression vector carrying the neuropeptide Y gene reduces mossy fiber sprouting and inhibits abnormal synaptophysin expression, thereby suppressing post-epileptic synaptic reconstruction.

Investigation of optimum discharge characteristics and chemical activity of AC driven air plasma jet and its anticancer effect

In this study,we investigated the effects of the quartz tube diameter,air flow rate,and applied voltage on the characteristics of an air plasma jet to obtain the optimized discharge characteristics.The physicochemical properties and concentration of reactive oxygen and nitrogen species(RONS)in plasma-activated medium(PAM)were characterized to explore their chemical activity.Furthermore,we investigated the inactivation effect of air plasma jet on tumour cells and their corresponding inactivation mechanism.The results show that the tube diameter plays an important role in sustaining the voltage of the air plasma jet,and the gas flow rate affects the jet length and discharge intensity.Additionally,the air plasma jet discharge displays two modes,namely,ozone and nitrogen oxide modes at high and low gas flow rates,respectively.Increasing the voltage increases the concentration of reactive species and the length of discharge.By evaluating the viability of A549 cells under different parameters,the optimal treatment conditions were determined to be a quartz tube diameter of 4 mm,gas flow rate of 0.5 SLM,and voltage of 18 k V.Furthermore,an air plasma jet under the optimized conditions effectively enhanced the chemical activity in PAM and produced more aqueous RONS.The air plasma jet induced significant cytotoxicity in A549 cancer cells after plasma treatment.H_(2)O_(2) and NO_(2) are regarded as key factors in promoting cell inactivation.The present study demonstrates the potential use of tumour cell therapy by atmospheric air PAM,which aids a better understanding of plasma liquid chemistry.

Photosynthetic Characteristics in Two Near Isogenic Lines of Winter Wheat

The development of near isogenic lines(NILs) is an important tool for physiological dissection of drought resistance in wheat. To better understand the potential for improving grain yield, a split-plot experiment was conducted under a mobile rain shelter using NILs of winter wheat with significant differences in the photosynthetic rate: the 908120 line with a high photosynthetic rate and the 908206 line with a low photosynthetic rate. The results indicated that the net photosynthesis rate(Pn), stomatal conductance, and transpiration rate in flag leaves in line 908120 were significantly higher than that in line 908206 under uniform water treatments during the reproductive phase in replicated pooled-culture trials. The maximum quantum yield Fv/Fm value and ribulose-1,5-bisphosphate carboxylase/oxygenase(RuBPCase) activity value were higher in line 908120 than that in line 908206, whereas the intercellular CO_2 and cell membrane permeability in line 908120 were lower than that in line 908206. Higher leaf Pn, transpiration rate, and RuBPCase activity and lower membrane ion leakage rate ensured the robustness of line 908120 during times of irrigation and drought, which contributed to the maintenance of its high grain yield. Drought had a negative effect on these factors, resulting in decreased yield, and the photosynthesis rate of flag leaves markedly affected the yield in NILs of winter wheat. NILs are an important strategy for wheat adaptation to drought stress, but might not be the only mechanism causing the significant grain yield increase. Collectively, the characteristics of line 908120 resulted in a higher grain yield compared with that of line 908206. Further dissection of the drought avoidance mechanisms in wheat, as well as analysis and identification of the genes involved may be necessary.

Cobalt-Catalyzed Switchable[4+1]and[4+1+1]Spirocyclization of Aromatic Amides with 2-Diazo-1H-indene-1,3(2H)-dione:Access to Spiro Indene-2,1'-isoindolinones and Spiro Isochroman-3,1'-isoindolinones

Herein,we report a condition-controlled divergent synthesis of spiro indene-2,1'-isoindolinones and spiro isochroman-3,1'-isoindolinones through cobalt-catalyzed formal[4+1]and[4+1+1]spirocyclization of aromatic amides with 2-diazo-1H-indene-1,3(2H)-dione.When the reaction is carried out under air in ethyl acetate,spiro indene-2,1'-isoindolinones are formed through Co(II)-catalyzed C—H/N—H[4+1]spirocyclization.When the reaction is run under O2 in CH3CN,on the other hand,spiro isochroman-3,1'-isoindolinones are generated through Baeyer-Villiger oxidation of the in situ formed spiro indene-2,1'-isoindolinones with O2 as a cheaper and environmental-friendly oxygen source.In general,these protocols have advantages such as using non-precious and earth-abundant metal catalyst,no extra additive,high efficiency and regioselectivity.A gram-scale synthesis and the removal of the directing group further highlight its utility.

Parking reservation techniques:A review of research topics,considerations,and optimization methods

Growing private vehicle use and a limited supply of parking resources have increased competition for parking spaces.Ineffective searching for parking spaces is a significant barrier to smooth traffic flow.Smart technology-generated parking reservations are regarded as an excellent way to increase parking efficiency and lessen traffic.Although there is increased attention on smart parking research and parking reservation optimization,a scoping review is currently lacking.Therefore,the purpose of this paper is to provide a comprehensive review of the research literature related to parking reservations.Out of the original 438 publications identified in this search,99 were eventually chosen for analysis.The review categorized parking reservations into four research topics:inventory control,allocation decisions,pricing strategies,and performance evaluation.The elements considered in these research themes,modeling techniques,and evaluation criteria are explored in detail.In addition,the challenges and further enhancements of parking reservation optimization are discussed.It is believed that the findings from this study will be beneficial in further research on parking reservations.

原子钼催化剂配位结构的动态演变促进氢分子在浆态床加氢裂化过程中的高效活化

开发具有高原子利用率和高转化频率的高效催化剂,用于减压渣油浆态床加氢裂化过程中H2分子的活化至关重要.本文采用“聚合-热解-原位硫化”策略,首次报道了一种高效稳定的单原子钼催化剂用于减压渣油浆态床加氢裂化反应,并发现了单原子Mo活性位点的原子配位结构动态演化机制.在VR加氢裂化过程中,与Mo配位的O原子逐渐被S原子取代,从而导致O/S交换过程.单原子钼的配位结构从反应前的Mo-O3S1演变为反应后的Mo-O1S3配位构型,有效促进了H2分子均裂活化为H自由基物种.所演变的单原子钼催化剂表现出优异的催化加氢活性和循环稳定性,其对减压渣油的单程转化率为65 wt.%,轻油收率为93 wt.%,焦炭产率仅为0.63 wt.%,按照所有金属计算的转化频率为0.35 s^(-1).理论计算表明,H2相互作用前后Mo 4d占据态的显著变化与单原子钼催化剂结构的动态演变有直接关系,并且Mo-O1S3位点较低的d带中心表明原子H扩散容易,有利于催化加氢.本文研究结果对于开发高原子经济性催化剂用于重油改质技术的工业应用具有重要意义.

Radio-frequency system of the high energy photon source

Purpose High energy photon source is a 6 GeV diffraction-limited storage ring light source currently under construction in Beijing.A low-frequency fundamental radio-frequency(rf)system of 166.6 MHz was proposed to accommodate the accelerator physics design.Superconducting rf(srf)technologies were chosen for the storage ring rf accompanied by solid-state power amplifiers and digital low-level rf controls.The design of the rf system was completed,and the parameters are frozen.Elucidation of the rf design with key parameters is desired.Methods The requirements from the accelerator physics design will be presented followed by the detailed rf design.The logic behind the choice of key rf parameters is elaborated.The configuration of the entire rf system is presented.Results and conclusions The fundamental srf cavity of 166.6 MHz was designed to accelerate the ultrarelativistic electron beam.Heavy damping of higher-order modes in these cavities is required to avoid the coupled bunch instabilities.An active third harmonic srf of 499.8 MHz was adopted to realize the required rf gymnastics.Normal-conducting 5-cell cavities will be used for the booster rf.Solid-state amplifiers of 2.4 MW in total will be installed at HEPS to drive these cavities in the booster and the storage ring.A digital low-level rf system will be used to regulate rf field inside each cavity with high stabilities.The rf configuration during the commissioning and the operation scenarios are also presented.

植物磷脂酸的特性及其在ABA诱导气孔运动中的作用

磷脂酸(PA)是应答多种生理过程的第二信使,其作为一个脂质信号快速积累从而响应多种环境。PA主要通过磷脂酶D (PLD)和磷脂酶C/甘油二酯激酶(PLC/DGK)途径产生。基于PLDs的生化特性、激活机制以及在不同类型胁迫下被激活的特定同种型的差异,不同类型胁迫下会产生特定分子种组成的PA。PA在多种环境下起信号转导作用,在调节气孔运动中,PA的作用模式主要是通过与多种蛋白结合,激活或抑制这些蛋白的活性,进而执行其信使功能。该文主要综述PA的生化特性以及信号途径中PA互作蛋白的研究进展,并提出PA研究中亟待解决的问题及今后的重点研究方向。

钴催化剂均相催化氢化以及脱氢反应的研究进展

近年来,铁、钴、镍和锰配合物催化体系在廉价金属催化领域取得了系列进展.由于其独特的性质和出色的催化性能,钴配合物在均相催化反应中最引人注目,所涉及的(脱氢)氢化反应在学术研究和化工行业中起着重要作用.本文根据氢化、转移氢化、无受体脱氢、脱氢偶联、借氢等反应类型总结了均相钴催化氢化、脱氢反应的研究进展,并概述了钴催化剂的反应性能、催化应用以及反应机理.

Characterization of particle size distribution of mainstream cigarette smoke generated by smoking machine with an electrical low pressure impactor

Cigarette smoking is a particle-related exposure. Studying the characteristics of the particle size distribution of cigarette smoke can aid in providing knowledge of smoke aerosol attributes. We used an electrical low pressure impactor （ELPI） to measure the particle size distribution of mainstream cigarette smoke generated by a smoking machine and provided a continuum of particle sizes of cigarette smoke from a whole cigarette. The results showed that the aerodynamic diameters （D, geometric mean of a channel） of particles ranged from 0.021 to 1.956 ~m, and the number concentrations were on the order of 105-109 cm-3 for different sizes of particles. The particle number of the size category below 0.1 p,m approximated that of the category 0.1-2.0 Ixm, and the particles in the size category of 0.1-2.0 μm contributed extremely heavily to total particulate mass. In addition, the results with small samples indicated that the tar yields normalized per milligram of nicotine showed an approximately linear increase with increasing concentration of total particles.

Active microphonics noise suppression based on DOB control in 166.6-MHz superconducting cavities for HEPS

Purpose Superconducting 166.6-MHz cavities will be used to accelerate electron beams in high-energy photon source(HEPS).The radio-frequency(RF)fields inside these cavities have to be controlled better than 0.03%(rms error)for the amplitude and 0.03◦(rms error)for the phase.Adopting a quarter-wave geometry withβ=1,the 166.6-MHz cavity has two intrinsic mechanical modes at∼100Hz observed in both simulations and cryogenic tests.If coupled to external vibrations,these microphonics modes shall stress the existing proportional–integral(PI)feedback controller and inevitably deteriorate the field stabilities.Therefore,additional noise suppression may be required.Methods Adigital low-level RF system previously in-house developedwas connected to a 166.6-MHz dressed cavity at room temperature in the laboratory.Piezo-tunerswere used to“knock”on the cavity at various frequencies to excite cavity vibrations,and microphonics spectrum was subsequently measured.A disturbance observer(DOB)-based algorithm was adopted and integrated into the existing feedback controller.The performance of PI controller,DOB controller and a combination of PI and DOB controller was compared.The limitation of the DOB controller was also examined.Results and conclusions The PI controller was proved to be insufficient in suppressing large cavity microphonics during the tests.By adding the DOB controller,the excellent field stabilities can be restored.Optimized loop parameters were obtained.The simple first-order filter was adequate thanks to the robustness of the DOB controller.This constitutes a first laboratory demonstration of the active microphonics noise suppression in the 166.6-MHz RF cavity for HEPS.

Synthesis of spirocyclopropylpyrazole derivatives via the cascade reaction of alkylidenecyclopropanes with pyrazolidinones and trifluoroethanol

A novel synthesis of spirocyclopropylpyrazole derivatives tethered with a trifluoromethyl unit through an unprecedented cascade reaction of alkylidenecyclopropanes with pyrazolidinones and trifluoroethanol(TFE)has been developed.

Trends in Incidence of HIV and Syphilis Among Men Who Have Sex with Men—Tianjin Municipality,China,2013-2022

Summary What is already known about this topic?Given the common modes of transmission,outbreaks of both human immunodeficiency virus(HIV)and syphilis are primarily observed in men who have sex with men(MSM).However,minimal research has been conducted to concurrently evaluate the rates and trends of HIV and syphilis incidence within this community in China.What is added by this report?

浅谈语义视角下的网络脏话

网络脏话作为网络交流中一种特殊的语言现象,具有独特的语义特征和社会影响。本文从语义视角出发,通过对网络脏话的语义构成、语义演变和语义功能进行深入分析和探讨,旨在揭示网络脏话对社会交往的影响,并提供对网络脏话现象的深入理解和应对策略的参考,促进网络交流的健康发展。