探讨姜黄素通过NF-κB对鼻咽癌CNE-2Z细胞的生长抑制作用、诱导凋亡作用及其机制研究

目的:探讨姜黄素通过NF-κB对鼻咽癌CNE-2Z细胞增殖的影响。方法:MTT法测定姜黄素对鼻咽癌CNE-2Z细胞增殖的影响,采用流式细胞仪测定姜黄素不同浓度下的CNE-2Z细胞凋亡情况,Western Blot测定NF-κB蛋白的表达。结果:姜黄素能影响CNE-2Z细胞的NF-κB蛋白表达,使NF-κB蛋白表达水平降低,说明姜黄素对CNE-2Z的增殖和转移有一定的影响。姜黄素对CNE-2Z的作用效果受作用时间和浓度影响,其对CNE-2Z细胞24 h的IC50数值为(43.514~45.435)μmol/L,48 h的IC50数值为(8.366~13.11)μmol/L,72 h的IC50数值为(5.658~8.469)μmol/L。结论:姜黄素能够通过NF-κB蛋白的表达,来抑制鼻咽癌CNE-2Z细胞增殖与侵袭。姜黄素浓度越高,作用时间越长,CNE-2Z细胞增殖抑制效果越好。

Co_(3)S_(4)/PES催化膜反应器氧化降解水中罗丹明B

基于过硫酸氢钾(PMS)的非均相高级氧化工艺(AOPs)在实际应用中一直受到PMS活化效率与活性氧物种(ROS)利用率低下的限制。本文以ZIF-67为前驱体、聚醚砜(PES)多孔膜为基底,采用金属有机框架(MOFs)模板配体交换策略,流动合成构建了Co_(3)S_(4)/PES催化膜反应器(CMR)。通过场发射电子显微镜(FESEM)、X射线衍射(XRD)等方法对催化膜进行了表征。结果显示,平均粒径为23 nm的Co_(3)S_(4)纳米颗粒被原位合成固载在PES膜孔中,负载量为15.9%,并沿膜厚度方向均匀分布。以活化PMS降解典型芳香族有机化合物罗丹明B(RhB)为例,研究了该催化膜的催化性能及反应机理。实验结果表明,浓度为20 mg/L的RhB溶液,在初始溶液pH为7、温度为25℃以及膜通量为0.80 mL/(min·cm^(-2))(对应于停留时间0.68 s)的条件下,Co_(3)S_(4)/PES催化膜具有90%以上的降解率,表观反应速率常数为97.83 min^(-1),转化频率达到了489.15 L/(min·g^(-1)),均高出Co_(3)S_(4)粉末传统悬浮间歇处理模式两个数量级,并且Co_(3)S_(4)/PES催化膜能够保持良好的稳定性。膜孔道的分散性有效防止了Co_(3)S_(4)纳米颗粒的聚集,过膜流动反应限域在微纳尺度的膜孔道内,强化了反应物与催化剂之间的质量传递与接触,加快了PMS的活化,从而实现了单线态氧(^(1)O_(2))的高效生成,并在RhB的快速降解中起主导作用。

EXACT SOLUTIONS FOR BELOUSOV-ZHABOTINSKII REACTION-DIFFUSION SYSTEM

We consider the following simplified model for the Belousov-Zhabotinskii(B-Z) reaction:?u/?t=u(1-u-rv)+d?~2u/?x^2,?v/?t=-suv+?~2v/?x^2,where r and s are positive parameters, and d is the diffusing constant for the concen-tration u. Seeking travelling wave front solution and making an ansatz for the solution,we obtain a nonlinear system of algebraic equations. The system is solved using WuElimination and then we are able to find several exact solutions which are of interest.

Analytic Solution of the Three-Variable Dynamical Equations of Oscillation Phenomena in B-Z Reaction

The dynamical behaviour of the inorganic bromate oscillator catalyzed by manganese ions in the B-Z reaction is discussed, a three-variable nonlinear dynamical equations of the oscillation phenomena have been obtained, and an analytic solution and numerical results of the equations are given.

Thermokinetic Behaviour Degenerated from Limit Cycle Oscillation of Isothermal B-Z Reaction System due to Temperature Controlling of Heat Compensation Type

The thermokinetic behavior of the B-Z reaction system was influenced by both the chemical reaction-heat conduction coupling and the temperature undulation due to temperature controlling of heat compensation type. Quantitative research indicated that this kind of temperature fluctuation will lead to limit cycle degeneration and the periodic or quasi-periodic response behavior of the focus near a supercritical Hopf bifurcation .

Optimization of competitively differentiated poiymerase chain reaction in detection of HBV basal core promoter mutation

AIM:To improve competitively differentiated polymerase chain reaction (CD-PCR) in detection of HBV basal core promoter mutation. METHODS: Recombinant plasmid of double point mutation A1762T/G1764A in basal core promoter of HBV constructed by site-directed mutagenesis was used as mutant control. To reveal the deficiency mechanism of CD-PCR, relationship between the circle number of PCR and the increased speed of products of each competitive primer was comparatively studied. Diversified amount of dNTPs and mutual primer of the competitive primers were tried to optimize CD-PCR. Optimized CD-PCR was evaluated by detecting A1762T/G1764A mutation in recombinant plasmids and clinical sera from patients with HBV infection. RESULTS: The deficiency mechanism of CD-PCR was that the products of mismatched competitive primer grew fast when the amplification of matched primer entered into plateau stage, which led to decrease in or disappearance of the difference in the amount of their products. This phenomenon could be eliminated by reducing dNTPs to 10μmol/L and mutual primer to about 100μmol/L Optimized CD-PCR could detect both mutant and wild strain independent of the amount of templates and the number of PCR cycles. Its detection limit was 103 copies/mL, about 50 copies/reaction. About 10% of mutant DNAs among wild type DNAs could be detected. A1762T/G1764A mutant was detected in 41.8% (51/122) of patients with HBV infection, but not detected in controls with negative HBsAg. CONCLUSION: Optimized CD-PCR can detect mutation independent of the amount of initial templates and the number of PCR cycles.

Theoretical Study on the Addition Reactions of Benzaldoximes with Propene

The Michael addition reactions of Z and E benzaldoximes with propene were investigated theoretically by DFT method at B3LYP/6-31G^＊ level. The calculation results show that both addition reactions are concerted processes accompanied by the migration of hydrogen from the atom oxygen to carbon. Both products Z and E nitrones have dipolar charge distributions and activities. Z isomer is more favorable in the reaction due to the barrier is lower.

基于硫磺素T核酸探针级联信号体系的荧光免疫分析方法用于食品中黄曲霉毒素B 1的检测

为开发能应用于复杂的食品基质中且准确高、灵敏高、特异性好的黄曲霉毒素B 1(aflatoxins B 1,AFB 1)检测方法,该研究以抗体偶联的磁性纳米微球(MMPMs-AFB 1抗体)为捕获探针,包被原/葡萄糖氧化酶(glucose oxidase,GOx)偶联的纳米微球(AFB 1-OVA-PPs-GOx)为信号探针,结合芬顿反应-硫磺素T荧光核酸探针体系开发了一种“Turn on”型AFB 1磁分离荧光免疫分析方法。结果显示,该方法对AFB 1的检测范围为0.05~50 ng/mL,最低检测限为0.027 ng/mL。在AFB 1的添加质量浓度为1、5、20、200 ng/g(ng/mL)的加标植物源性食品样品中,AFB 1的回收率良好,为81.6%~112.1%,变异系数值为1.2%~15.8%。该方法成功应用于玉米粉质控样品中AFB 1的检测。结果表明,所建立的方法灵敏度高,特异性好和抗基质干扰能力强,可用于食品中的AFB 1的精确定量检测。

Epidemiological and Subtype Characterization of Influenza Viruses Infection in Children in Shenzhen, China during Three Consecutive Seasons (January 2016-December 2018)

Background: Children with seasonal influenza infection cause a significant burden of disease each year in the pediatric clinic. Influenza A and B viruses are the major types responsible for illness. A better understanding of the periodicity facilitates the prevention and control of influenza in children. Objective: This study aims to analyze the epidemiological patterns and subtype characterization of influenza viruses among children in Shenzhen, China. Methods: Influenza samples were collected by nasopharyngeal swabs from influenza like illness patients in Shenzhen Children’s Hospital from January 2016 to December 2018. The positive cases and influenza subtypes were determined by gold labeled antigen detection and reverse transcriptase polymerase chain reaction. The influenza periodicity and age, subtype distribution as well as the association between climate parameters and different influenza subtypes were analyzed by SPSS 22.0. Results: The influenza positive rate during 2016-2018 was 21.0%, with a highest positive rate in the year 2018. The positive rate varied by month, season, and year describing a sequence of peaks presenting primarily in all year including spring, summer and winter. The characteristics of influenza peak were different in each year, with a spring peak in 2016 and a summer plus a winter-spring peaks in 2017 and 2018. In addition, influenza B exhibited a winter-spring seasonal pattern while influenza A displayed a more variable seasonality, highlighting influenza B rather than influenza A which had a negative association with climate parameters. Influenza-positive cases were older than influenza-negative cases (P P Conclusion: Influenza activity in children from Shenzhen typically displays both winter-spring and summer peaks. Influenza A epidemic occurred separately or co-circulated with influenza B, with a winter-spring pattern for influenza B and a much more variable seasonality for influenza A. Influenza B had a negative association with climate parameters. In addition, hospitalization with influenza often occurs in younger individuals infected with influenza A.

Seroprevalence of Human Immunodeficiency Virus and Hepatitis B in Blood Donors at the N’Zérékoré Regional Blood Transfusion Centre in Guinea

Blood transfusion saves lives and reduces morbidity and mortality for a large number of diseases and clinical conditions, but it is not without danger. The aim of this study was to determine the seroprevalence of HIV and hepatitis B in blood donors received at the regional Blood Transfusion Centre of N’Zérékoré (Guinea). This was a 5-year retrospective analytical study. We included records of blood donors aged 18 to 60 years admitted to the N’Zérékoré Regional Blood Transfusion Centre for blood donation from January 2016 to December 2020. We performed a descriptive analysis followed by Chi-2 or Fish-er-exact tests and the Student or Wilcoxon test, followed by multivariate logistic regression. In this study, donor age ranged from 18 - 60 years, with a pre-dominance of donors aged 25 - 34 (44.2%). Male donors were the most represented in our study (79.0% versus 21.0% female). More than half of the donors were blood group O (55.6%). We observed a seroprevalence of 3.6% for HIV, 13.4% for HBsAg and 0.2% for co-infection. In our series, age 25 - 34 (OR = 1.89 and P = 0.001) and 35 - 44 for HIV (OR = 2.01 and P = 0.001), HBsAgserostatus (OR = 3.04 and P = 0.001) and blood donation history (OR of 3.04 and P = 0.001) were factors associated with HIV positivity (P < 0.05). In our study, HIV serostatus (OR = 3.04 and P = 0.001) and blood donation history (OR = 0.01 and P = 0.001) were factors associated with HBsAgseropositivity. We reported a high prevalence of HIV and HBsAg. Sex, serological status and blood donation history were associated factors.

A novel synthesis of pyrazolo[3,4-b]pyridine derivatives through multi-component reaction in ionic liquid

An efficient and novel procedure for the preparation of pyrazolo[3,4-b]pyridine derivatives through multi-component reaction of aldehyde, 5-amino-3-methyl-1-phenylpyrazole and malononitrile or cyanoacetate in [bmim][BF4] is described in this paper. Advantages of the method presented here include mild conditions, high yields together with a green nature and ease of recovery and reuse of the reaction medium.

Simulation method for measurement of the cross-section of the^(14)N(n,a)^(11)B reaction using a gridded ionization chamber

A simulation method for measurement of the cross-section of the^(14)N(n,a)^(11)B reaction with gas and solid samples using a gridded ionization chamber(GIC)has been established.Using the simulation,the experimental spectra of both^(14)N(n,a)^(11)B events and background from other reactions can be predicted,and the experimental scheme can be optimized.According to the simulation results,the optimal experimental parameters,including the pressure of the working gas and the compositions of the working gas and the sample,can be determined.In addition,the simulation results can be used to determine the valid event area and calculate the detection efficiency for valid events.A measurement of the cross-sections of the^(14)N(n,a)^(11)B reaction at E_(n)=4.25,4.50,4.75,5.00,5.25,and 5.50 MeV,based on the 4.5-MV Van de Graff accelerator at Peking University(PKU)using a GIC as the detector for the outgoing a particles,has been performed.The good agreement of the spectra from the simulation and experiment demonstrated the universality of this simulation method,which can be used to accurately measure neutroninduced light-charged particle emission reactions.

Expansion Reaction of μ-FcCCHCo_2(CO)_6 with Benzylideneacetonetricarbonyliron, and Molecular Structure of μ_3-FcCHCFeCo_2(CO)_9

The vinylidene-bridged cluster μ_3-FcCHCFeCo_2(CO)_9 2 was prepared by the expansionreaction of ferrocenyl-acetylene dicobalt complex μ-FcCCHCo_2(CO)_6 1. Benzylideneacetone-tricarbonyliron [(BDA)Fe(CO)_3] was used as the source of Fe(CO)_3. The molecular structure of thecluster 2 was detendned by x-ray structural analysis.

Density Functional Theory Study on the Addition Reactions of 4-methyl-benzaldoximes with Propene

The Michael addition reactions of Z and E 4-methyl-benzaldoximes with propene were investigated theoretically by DFT method at B3LYP/6-31G* level.The calculation results show that both addition reactions are concerted processes accompanied by the migration of hydrogen from the atom oxygen to carbon.Both products Z and E nitrones have dipolar charge distributions and activities.Z isomer is more favorable in the reaction due to the barrier is lower.

How Effective Is the Single-point Energy Calculation in Investigating the Reaction Mechanisms?New Decarboxylation Mechanism of Pyrrole-2-carboxylic Acid by Full Optimization with CPCM Solvation Model

The decarboxylation of pyrrole-2-carboxylic acid in acid solutions was elucidated by full optimization with the CPCM solvation model at the B3LYP/6-31 l＋＋G（d,p） level. Compared with the single-point energy calculation, CPCM full optimization is better to model solvent environments to gain reasonable reaction mechanisms. The π interactions play a significant role in the decarboxylation of pyrrole-2-carboxylic acid （R）. Firstly, the a hydrogen is protonated, but all of the carbonyl hydration pathways bear relatively higher energy barriers. The carbonyl group can rove over the pyrrole ring, but it does not lead to the speciation of pyrrole and protonated carbon dioxide for the latter is an energy-rich species. The decarboxylation mechanism proposed here is that, the protonated pyrrole-2-carboxylic acid （RH） decarboxylates via direct C-C bond cleavage with the aid of a water molecule to accommodate the proton on the carbonyl group.

DFT studies on the SCR reaction mechanism of nitrogen monoxide with propylene catalyzed by copper oxide

The SCR reaction mechanism of NO with C3H6catalyzed by CuO was studied by the method of Density Functional Theory(DFT)at the B3LYP/LanL2DZ levels.The optimized geometries of the stationary points on the potential surface were obtained and the transition state was confirmed by IRC and vibration analysis.The activation energy was calculated being 34.26 kJ/mol.It was shown that propylene reacted firstly with Cu forming intermediate,and then nitrogen monoxide immediately reacted with the intermediate to be reduced.It was proved to be a direct interaction mechanism.

DFT Study on the (S)-Proline-catalyzed Direct Aldol Reaction between Acetone and 4-Nitrobenzaldehyde

DFT/6-31G^＊ calculations were applied to study the direct aldol reaction between acetone and 4-nitrobenzaldehyde catalyzed by （S）-proline. Four transition states associated with the stereo-controlling step, corresponding to syn and anti arrangements of methylene moiety related to the carboxylic acid group in enamine intermediate and re and si attacks to the aldehyde carbonyl carbon have been obtained. The solvent effect of DMSO was investigated with polarized continuum model. The computed energies of transition states reveal the stereo-selectivity of the reaction.

NO_2^-三乙醇胺对B-Z振荡反应的影响

对NO-2 三乙醇胺对B Z振荡反应 ,NO-2 的浓度的对数 1n[NO-2 ]与诱导期倒数的对数 1n(1/tin)有良好的线性关系 ,线性范围为 3× 10 -5～ 3× 10 -3 mol·L-1,在此浓度范围内 ,NO-3 、三乙醇胺均无影响 ,该体系重现性好、灵敏度高、操作简单。获得诱导期、周期的表观活化参数Ein、Ep 分别为 4 1 86、5 7 0 1kJ·mol-1。

二苯胺磺酸钠对B-Z振荡反应的影响

研究了B Z振荡体系在各种组分不同浓度下周期和振幅的改变值与加入二苯胺磺酸钠浓度的关系 .结果表明第一个周期改变值与加入浓度有良好线性关系 ,相关系数均大于 0 9916 .改变组分浓度 ,可适当提高检测浓度范围 .

Theoretical Study on the Reaction Mechanism of 2-Methoxybenzaldehyde,4-Bromo-indanone,Malononitrile and Ammonium Acetate One-pot to Form 6-(2-Methoxyphenyl)-2-amino-6-bromo-5H-indeno[1,2-b]pyridine-3-carbonitrile

The reaction mechanism of 2-methoxybenzaldehyde, 4-bromo-indanone, malononitrile and ammonium acetate one-pot to form 6-（2-methoxyphenyl）-2-amino-6-bromo-5 Hindeno[1,2-b]pyridine-3-carbonitrile was studied by density functional theory. The geometries of the reactants, transition states, intermediates and products were optimized at the PW91/DNP level. Vibration analysis was carried out to confirm the transition state structure. Reaction pathways were investigated in this study. The result indicates that the reaction Re→ TSB1→IMB1→ TSB2→ IMB2→TSB3→IMB3→TSB4→IMB4→TSB5→IMB5→TSB6→IMB6→TSB7→IMB7→ TSB8→IMB8→TSB9→IMB9→P2 is the main pathway, the activation energy of which is the lowest. The dominant product predicted theoretically is in agreement with the experiment results.