Blocking beta 2-adrenergic receptor inhibits dendrite ramification in a mouse model of Alzheimer's disease

Dendrite ramification affects synaptic strength and plays a crucial role in memory. Previous studies revealed a correlation between beta 2-adrenergic receptor dysfunction and Alzheimer＇s disease （AD）, although the mechanism involved is still poorly understood. The current study investigated the potential effect of the selective β2-adrenergic receptor antagonist, ICI 118551 （ICI）, on Aβ deposits and AD-related cognitive impairment. Morris water maze test results demonstrated that the performance of AD-transgenic （TG） mice treated with ICI （AD-TG/ICI） was significantly poorer compared with NaCl-treated AD-TG mice （AD-TG/NaCl）, suggesting that β2-adrenergic receptor blockage by ICI might reduce the learning and memory abilities of mice. Golgi staining and immunohistochemical staining revealed that blockage of the β2-adrenergic receptor by ICI treatment decreased the number of dendritic branches, and ICI treatment in AD-TG mice decreased the expression of hippocampal synaptophysin and synapsin 1. Western blot assay results showed that the blockage of β2-adrener- gic receptor increased amyloid-β accumulation by downregulating hippocampal a-secretase activity and increasing the phosphorylation of amyloid precursor protein. These findings suggest that blocking the β2-adrenergic receptor inhibits dendrite ramification of hippocampal neurons in a mouse model of AD.

Association between essential hypertension and polymorphisms of beta 1 adrenergic receptor gene G1165C (Gly389Arg) in Chinese Mongolian population

BACKGROUND： The prevalences of hypertension, cerebrovascular diseases, etc. are higher in Mongolian population because of the influence of various factors including genetics, geography, diet, etc. Therefore, it is helpful to develop researches on the genetics of various diseases including hypertension in Mongolian population. OBJECTIVE： To analyze the association between the polymorphism of beta1 adrenergic receptor （β1-AR） gene G1165C （Arg389Gly）, an important candidate gene for various diseases of cardiovascular system, and essential hypertension in Mongolian population. DESIGN ： A cross-sectional study SETTINGS： Department of Neurology, the First Affiliated Hospital of Inner Mongolia Medical College; Wulate Houqi Red Cross Society. PARTICIPANTS： The survey was carried out from February 2003 to March 2005. Totally 239 Mongolian residents, whose blood relations of 3 generations were all Mongolians, were selected from Wulate Houqi, Inner Mongolia, and they were all informed with the survey and detected items. Based on the diagnostic standard of hypertension set by WHO in 1999, the subjects were divided into two groups according to the level blood pressure： ① Normal blood pressure group （n=117）： systolic blood pressure （SBP） 〈 140 mm Hg （1 mm Hg =0.133 kPa）, diastolic blood pressure （DBP） 〈 90 mm Hg, and those having histories of cerebrovascular disease, heart disease, diseases of liver, kidney and tiroides, and diabetes mellitus were excluded. ② Essential hypertension group （n=122）： including 51 patients with simple high SBP. All the enrolled subjects had no blood relationship with each other, and had no history of miscegenation. METHODS ： The body height, body mass, waist circumference and blood lipids were measured routinely, and their habits of smoking and drinking were also investigated. Penpheral venous blood （5 mL） was drawn, the genome DNA was extracted, and the polymorphisms of the β1-AR Gl165C （Gly389Arg） genotype were detected with the Sequenom system. Polymerase chain reaction （PCR） experiment and SNP detection were performed in Huada Gene Laboratory of Bejing, then the univariate analysis of variance was applied in the sample comparison among groups, and the chi-square test was used to compare the genotypes and allele frequencies. The odd ratio （OR） and 95% confidence interval （CO were calculated. MAIN OUTCOME MEASURES： The distributions of β1-AR Gl165C （Gly389Arg） genotypes and alleles were observed. RESULTS： A11 the 239 subjects were involved in the analysis of results, and no one missed, ①Comparison of β1-AR G1165C （Gly389Arg） genotypes and allele distnbutions： In Mongolian population, the frequencies of CC and GG＋GC genotypes at β1-AR G1165C （Gly389Arg） site in the essential hypertension group （72%, 28%） were not significantly different from those in the normal blood pressure group （67%, 33%） （xz=0.841, P=-0.359; OR 0.773, 95%Cl： 0.445-1.342）; The frequencies of C and G alleles also had no significant differences between the essential hypertension group （85%, 15%） and the normal blood pressure group （82%, 18%） （x^2=1.136, P=-0.287; OR： 0.769, 95%Cl： 0.747-1.248）. ②The frequencies of CC and GG＋GC genotypes at β1-AR G1165C （Gly389Arg） site had no significant differences between the patients with simple high SBP （71%, 29%） and the normal blood pressure group （x^2=0.250, P=-0.617; OR： 0.833, 95%C/： 0.408-1.703）; The frequencies of C and G alleles were not significantly different between the patients with simple high SBP （86%, 14%） and the normal blood pressure group （x^2=0.670, P=-0.413; OR 0.766, 95%Cl： 0.404-1.453）. CONCLUSION： In Mongolian population, the distributions of the genotypes and alleles of β1-AR Gl165C （Gly389Arg） have no obvious differences between the subjects with normal blood pressure and the patients with essential hypertension （including simple SBP increase）, which suggests that G1165C （Glu389Asp） site of β1-AR gene may be not a genetic mark of essential hypertension and simple high SBP in Mongolian population.

Effect of Cardiopulmonary Bypass on Beta Adrenergic Receptor Adenylate Cyclase System on Surfaces of Peripheral Lymphocytes

Summary: The experimental results showed that the level of CAMP, the ratio of cAPM to cGMP, IL-2R expression and IL-2 production in vitro in lymphocytes immediate and 2 weeks after car- diopulmonary bypass (CPB) were significantly lower than those before anesthetics in the patients undergoing cardiac surgery with CPB. These findings suggested that CPB could cause serious damage to adrenergic beta receptor-adenylate cyclase system on circulating lymphocytes surfaces, which might be one of the mechanisms resulting in immunosuppression after open heart surgery with CPB.

Changes of pulmonary beta-adrenergic receptors and their relationship with membranous phospholipid metabolism in endotoxin-induced lung injury in rats

The changes of beta-adrenergic receptors (AARs) in lung tissue in endotoxin-induced acute lung injury was investigated with radioligand bindig assay in rats. The lipid fluidity and phospholipid content of the cellular membrane of lung tissue were measured with fluorescent polarization and high performance liquid chromatography respectively. The findings were as follows:1- Four hours after endotoxin injection, there was a 47% decrease of the maximal binding capacity of fyARsas compared with the control.2. Endotoxin was able to decrease the lipid fluidity and phospholipid content of the pulmonary cellular membrane markedly and at the same time. There was an elevated activity of phospholipase A2 in the pulmonary tissueThese findings suggest that the decrease of the binding capacity of &ARs results in a decrease of the PAR mediated functions, which plays a ro1e in the pathogensis of endotoxin-induced acute lung injury and the activation of phospholipase A2 which is an important factor to reduce the phospholipid content of cell membrane and subsequently to decrease its lipid fluidity, can result in a reduction of the lateral diffusion and rotatory movement of β-ARs and to decrease the chances of β-ARs to bind with the ligands.

Inhibition of central sympathetic nervous tone improves cardiomyocyte contraction by increasing the response of beta 2-adrenergic receptor in aged rats

In the present study,selective β1-adrenergic receptor antagonist CGP20712A and selective β2-adrenergic receptor antagonist ICI 118551 were administered to isolated cardiomyocytes from young （4-6 months）,aged （18-20 months）,and clonidine-pretreated aged （18-20 months） Sprague-Dawley rats.Cardiomyocyte contraction amplitude was measured to assess cardiomyocyte response to the β-adrenergic receptor agonist,isoprenaline.CGP20712A reduced cardiomyocyte contraction amplitude in young and aged groups and significantly reduced contraction amplitude in cells from young rats.ICI 118551 had no effect on cardiomyocyte contraction amplitude in young rats,but significantly decreased contraction amplitude in the aged groups,in particular in the clonidine-pretreated aged rats.Results demonstrated that reduced central sympathetic tone improved cardiomyocyte contraction in aged rats by improving the response of β2-adrenergic receptor to isoprenaline.

Beta-adrenergic receptor polymorphisms: A basis for pharmacogenetics

Aims: Polymorphisms of the β-adrenergic receptor, the frequency of which may differ in ethnic groups, alters β-receptor function. The aim of this study was to elucidate the frequency of β1 and β2-adrenergic receptor polymorphisms in healthy Greeks and to compare with those of Caucasian European (Euro) and African American (AA) origin. Methods: Ninety-nine individuals with a median age of 63 without clinical evidence of any disease were studied. Blood samples were obtained and common β1 and β2-adrenergic receptor polymorphisms that change the en-coded amino acid were determined by pyrosequencing. Results: The most common β1-adrenergic receptor polymorphism in Greeks is nucleotide substitution cytosine for guanine at position 1165 (1165 C/G) resulting in amino acid substitution arginine for glycine at position 389 (389 Arg/Gly) with a minor allele frequency of 28% (Euro 27%, AA 42%);this polymorphism increases the sensitivity of the β1-receptor. The most common β2-adrenergic receptor polymorphism in Greeks is the nucleotide substitution guanine for adenine at position 46 (46 G/A) resulting in amino acid substitution glycine for arginine at position 16 (16 Gly/Arg) with a minor allele frequency of 38% (Euro 41%, AA 50%);this polymerphism facilitates receptor down-regulation during chronic adrenergic stimulation. Conclusion: The most common β1 and β2-adrenergic receptor polymorphisms in the Greek population are similar to those of other European ancestry, and less common than in those of African origin indicating variability in ethnic groups. This information provides insight into common polymorphisms that may assist in optimizing β-antagonist and agonist therapy.

Association between Depression, Pressure Pain Sensitivity, Stress and Autonomous Nervous System Function in Stable Ischemic Heart Disease: Impact of Beta-Adrenergic Receptor Blockade

Background: Depression and ischemic heart disease (IHD) are associated with persistent stress and autonomic nervous system (ANS) dysfunction. The former can be measured by pressure pain sensitivity (PPS) of the sternum, and the latter by the PPS and systolic blood pressure (SBP) response to a tilt table test (TTT). Beta-blocker treatment reduces the efferent beta-adrenergic ANS function, and thus, the physiological stress response. Objective: To test the effect of beta-blockers on changes in depression score in patients with IHD, as well as the influence on persistent stress and ANS dysfunction. Methods: Three months of non-pharmacological intervention aiming at reducing PPS and depression score in patients with stable IHD. Beta-blocker users (N = 102) were compared with non-users (N = 75), with respect to signs of depression measured by the Major Depressive Inventory questionnaire (MDI), resting PPS, and PPS and SBP response to TTT. Results: MDI score decreased 30% in non-users (p = 0.005) compared to 4% (p > 0.1) among users (between-group p = 0.003;effect size = 0.4). Resting PPS decreased in both the groups. Among most vulnerable patients with MDI ≥ 15, reductions in MDI score and resting PPS score correlated in non-users, only (r = 0.69, p = 0.007). Reduction in resting PPS correlated with an increase in PPS and SBP response to TTT. Conclusions: Stress intervention in patients with IHD was anti-depressive in non-users, only. Similarly, the association between the reduction in depression, reduction in persistent stress, and restoration of ANS dysfunction was only seen in non-users, suggesting a central role of beta-adrenergic receptors in the association between these factors.

经颅磁声电刺激对健康与帕金森病大鼠神经回路中beta振荡的影响

背景:经颅磁声电刺激是一种基于磁声耦合电效应的无创、高精度脑神经聚焦刺激方法,可调节神经节律振荡活动,从而影响大脑的运动、认知等功能。目的:探究经颅磁声电刺激对健康与帕金森病大鼠神经回路中beta振荡的影响。方法:①动物实验:采用随机数字表法将24只Wistar大鼠随机分为4组,每组6只:正常对照组不进行任何干预;正常刺激组大脑前额叶皮质接受经颅磁声电刺激(空间峰值脉冲平均强度为13.33 W/cm^(2),基波频率为0.4 MHz,基波周期数为1000,脉冲重复频率为200 Hz);模型对照组、模型刺激组通过腹腔注射1-甲基-4-苯基-1,2,3,6-四氢吡啶建立帕金森病模型,造模成功后,模型对照组大脑前额叶皮质接受经颅磁声电假刺激,模型刺激组大脑前额叶皮质接受经颅磁声电刺激,每天刺激时长2.0 min,刺激结束停留8-10 min后,采集大鼠执行T迷宫过程中局部场电位信号并同时记录行为学正确率,对比分析各组局部场电位信号能量的时频分布情况和行为差异,当大鼠正确率连续3 d高于80%后停止刺激实验和T迷宫实验。②建模仿真实验:构建经颅磁声电刺激下皮质-基底神经节回路模型,分别改变超声发射周期(5,10,20 ms)、超声发射占空比(30%,50%,90%)和感应电流密度(20,50,100μA/cm^(2)),比较不同刺激参数下健康与帕金森病大鼠beta振荡的功率谱密度值。结果与结论:①动物实验:正常对照组大鼠的空间学习能力强于模型对照组(P<0.001),正常刺激组大鼠的空间学习能力强于正常对照组(P<0.05),模型刺激组大鼠的空间学习能力强于模型对照组(P<0.01);正常对照组beta振荡能量分布较为集中,正常刺激组较正常对照组beta振荡信号能量有所降低,模型对照组与模型刺激组beta振荡能量广泛分布且能量值显著高于正常对照组、正常刺激组,并且模型刺激组beta振荡信号能量明显低于模型对照组;②建模仿真实验:不加刺激时,健康大鼠beta频段功率谱密度峰值(30 dB)显著低于帕金森病大鼠(55 dB);施加经颅磁声电刺激后,两组大鼠beta频段功率谱密度值普遍降低;beta频段功率谱密度峰值与超声发射周期呈正相关、与感应电流密度呈负相关,当超声发射占空比为50%时功率谱密度峰值最低;③结果表明:经颅磁声电刺激可抑制健康与帕金森病大鼠的beta振荡,进而改善大鼠的运动功能与决策认知功能。

基于Beta分布的目标搜索概率自适应更新策略及其应用

针对不确定先验信息条件下的目标搜索问题,考虑传感器探测概率和虚警概率,设计了基于Beta分布的目标搜索概率自适应更新策略。首先,通过Beta分布建立了不确定先验环境的概率地图,并提出自适应目标搜索概率更新策略,使得无人机能够根据概率信息图动态更新检测次数;其次,在概率更新策略中引入了拒绝概率修正因子,根据地图概率差动态调整概率变化量,避免了搜索任务中可能存在的误检漏检问题;最后,通过数值仿真实验,验证了提出的目标搜索自适应更新策略可在不影响搜索效率的前提下,有效减小无人机的错误检测概率。

草甸草原植物beta多样性高光谱遥感估算方法

目前,全球生物多样性的状态非常堪忧,因此,利用光谱技术估算生物多样性成为了生态学家和遥感学家共同关注的热点。目前关于植物alpha多样性的研究很多,而关于beta多样性的研究较少,仍存在一些问题值得去探索。为了探究利用遥感技术估算植物beta多样性的最佳光谱指数以及最佳影像空间分辨率,以草甸草原为研究区,基于无人机高光谱遥感影像,从光谱距离、光谱角度、生物多样性概念三个方面计算了6种beta多样性估算指数(4种为我们构建的新指数,2种为已有的指数),并采用Mantel tests和相关系数筛选最佳的光谱指数。然后将筛选出来的指数应用于不同空间分辨率的影像,以期得到最佳观测尺度。另外,为了提高指数的估算能力,对比了一阶导数变换和Savitzky-Golay滤波两种光谱变换方法,以及相关系数法、连续投影法、竞争性自适应重加权法三种特征波段选择方法。结果表明,不论是采用亚尺度观测(像元大小<样方大小)还是等尺度观测(像元大小=样方大小),最佳的光谱指数均为光谱距离指数,且光谱距离指数在不同影像空间分辨率下均表现良好。在草原地区,当影像空间分辨率约为0.25 m时,该指数可以取得最佳的估算结果。经一阶导数变换并用相关系数法提取特征波段后构建的光谱距离指数与beta多样性拥有最强的相关性,今后可利用该指数构建估算模型或者直接表征beta多样性。该研究对于科学的选取光谱指数和影像空间分辨率去估算植物beta多样性具有一定的指导意义。

晶种辅助蒸气转化Al-SBA-15合成Beta纳米晶团聚体

采用晶种辅助蒸气转化(SASC)策略,将有序介孔分子筛Al-SBA-15颗粒直接转化为Beta纳米晶团聚体(BNA).除规则微孔外,BNA含有2种多级介孔结构.研究了骨架组装与多级孔结构的关系.通过调节热分解条件,将P123胶束选择性分解成碳颗粒并分散于Al-SBA-15介孔中,在颗粒内部构建了均匀的三维纳米空间网格.通过浸渍Beta晶种和四乙基铵阳离子(TEA+)强化分子筛成核,采用蒸气处理方法,将Al-SBA-15无定形孔壁在纳米空间中缓慢转化为Beta纳米晶体.通过调节合成参数,使纳米晶体沿Al-SBA-15孔壁方向规则排列,形成有序介观结构.此外,经高温焙烧去除碳颗粒后,BNA内部生成了穴状介孔.实验结果表明,低的溶剂用量可显著降低传质速度,提高骨架组装质量,从而使BNA酸性增强.优异的多级孔结构和较强的酸性使BNA在大分子反应中具有应用潜力.

基于高频数据的连续Beta、跳跃Beta与低Beta异象

本文基于二次变差和二次幂变差的方法，将股票价格按平滑程度划分为交易日内连续部分、日内跳跃部分和非交易时间隔夜部分，采用中国A股市场2001年1月至2016年7月的高频数据，分别估计个股的日内连续、日内跳跃和隔夜跳跃等三个类型的Beta，考察不同类型Beta的风险溢价情况。经验分析发现，采用单因素和双因素排序分组时，我国A股市场存在较强的低Beta异象，低Beta异象主要是日内收益跳跃部分引起的。控制了反转异象、特质波动率异象、最大日收益效应后，低Beta异象依然是显著的。但是，控制了流动性和换手率后，Beta的系数变得不再显著，说明在一定程度上我国股票市场的低Beta异象可以被流动性异象和换手率异象解释。

Beta@ZIF-67复合材料的制备及对聚乳酸塑料的催化降解性能

以聚乳酸(PLA)为代表的可降解塑料被认为是传统石油基塑料的合适替代品.然而,PLA自然降解的时间较长,同时伴随着CO_(2)的排放.因此,升级回收PLA更有利于实现可持续发展.本文通过将沸石咪唑酯骨架(ZIF-67)生长在Beta沸石表面,制备了一种Beta@ZIF-67复合材料.该材料可以实现废弃PLA塑料的高效催化降解,在180℃下反应4 h即可将日常生活中所用PLA塑料完全转化为乳酸甲酯(产率高达76.4%).这种高催化效率得益于复合材料开放的孔道结构和较大的比表面积,以及ZIF-67(Lewis酸/碱)与Beta分子筛(Brønsted酸)所提供活性位点的协同作用.本研究为沸石分子筛复合催化剂的设计合成及用于聚乳酸塑料催化降解提供了新的途径.

高原鼠兔干扰对高寒草甸植物物种和功能性状beta多样性的影响

采用野外空间多点同步取样,分析了高原鼠兔干扰对高寒草甸植物物种beta多样性和植物功能性状beta多样性的影响,确定了高原鼠兔干扰下高寒草甸植物物种和功能性状beta多样性的变化途径,分别提出了高原鼠兔干扰区域内,基于植物物种多样性和功能性状多样性的高寒草甸植物多样性维持策略。结果表明,高原鼠兔干扰使高寒草甸植物物种相似性显著降低了28.1%,植物功能相似性降低了28.7%。尽管高原鼠兔干扰没有改变高寒草甸植物物种和功能性状beta多样性的变化途径,且对植物物种和功能性状的嵌套组分不存在显著影响,但高原鼠兔干扰显著降低了植物物种和功能性状周转组分所占的比例,降幅分别为36.6%和34.3%。高原鼠兔干扰区域内,高寒草甸植物物种beta多样性的变化以周转为主导(周转占比81.4%;嵌套占比:18.6%),植物功能性状beta多样性的变化以嵌套为主导(嵌套占比64.9%;周转占比35.1%)。因此,针对划定的高原鼠兔干扰区,需要同时保护区域内所有高原鼠兔栖息地(多位点保护),以达到维持植物物种多样性的目的,而可以仅通过保护该区域内植物功能性状丰富的位点,即可维持较高的植物功能多样性。

响应面模型用于Beta分子筛催化剂蜂窝状整体式成型的研究

Beta分子筛由于具有独特的三维十二元环孔道结构,可提供更多活性组分附着位点,是在实际应用中具有优异性能的工业催化剂。在工业使用中,蜂窝整体式催化剂具有通量高、流场均匀、压降小、不易堵塞的优点,是气固或者液固催化反应的最优解决方案。但由于Beta分子筛吸水率高,收缩率大,导致蜂窝成型困难,严重限制了Beta分子筛的工业应用。基于此,选择拟薄水铝石(SB粉)为黏结剂、硝酸为胶溶剂、田菁粉为助挤剂,在水粉比为0.6的条件下制备一系列蜂窝整体式成型Beta分子筛催化剂,基于响应面法,评价了各原料的配比对蜂窝整体式催化剂机械强度的影响,得到了催化剂的机械强度与3个因素(黏结剂用量、胶溶剂用量、助挤剂用量)之间关系的二阶多项式近似模型函数。将试验结果与预测值进行对比,证明了预测模型的可靠性,并利用该模型找到最优的Beta分子筛蜂窝成型条件为SB粉质量分数36.1%、硝酸质量分数8.4%、田菁粉质量分数4.7%。

广义多元Beta分布

本文把广义Beta分布(Eugene(2001))推广到了多元的情形,研究了多元Beta分布的矩母函数,以及广义多元Beta分布的边际分布、条件分布及回归函数.给出了他们在次序统计量中的应用.

La掺杂改性Co-Beta催化丙烷脱氢

钴基催化剂在高温反应中易团聚烧结,且对其活性中心认识不足。为此设计了一种新型CoLa双金属催化剂,通过稀土金属La隔离并稳定钴物种,从而提高催化剂的反应活性。通过调控La在材料中的掺杂量,建立不同分散度与催化性能之间的构-效关系,以深入了解活性中心。采用XRD、XPS、化学吸附、探针分子红外等表征手段对催化剂中Co物种的存在形式、化学环境和尺寸大小等催化相关性质进行分析。结果表明,La的掺杂可以促进Co物种的分散,并增强Co物种与载体之间的相互作用。

基于Beta函数的温度分量模型在混凝土拱坝变形监控中的应用

混凝土拱坝由于具有特殊的超静定壳体结构,对温度尤其敏感,因此拱坝变形监控模型中的温度分量对模型综合性能有显著影响。使用常见的周期三角函数和平均温度等传统温度分量构建方法,无法很好地表示拱坝坝体内部的温度分布与外界温度的滞后效应。因此,提出了一种新的温度滞后特性模拟方法,采用Beta分布来描述滞后影响,并基于Beta函数建立了混凝土拱坝变形监控模型。将基于Beta函数的温度分量模型应用于某拱坝变形监控模型的建立,结果表明监控模型的拟合精度和预测精度均优于传统模型,并表征了前期气温对沿拱向坝体测点变形的影响权重分布,描述了气温对坝体变形的滞后效应。

Pt/Beta催化剂上Pt金属中心/酸中心浓度比对加氢异构化性能的影响

以工业Beta沸石为载体,负载不同含量的Pt,得到了不同金属中心/酸中心浓度比(c_(M)/c_(A))的催化剂,对其进行物化表征,并以正庚烷为模型化合物对不同c_(M)/c_(A)催化剂进行异构化反应性能评价。结果表明:Pt粒子均匀地负载在沸石的外表面上,对沸石结构没有影响,酸性略有下降。对于催化剂的正庚烷异构化反应活性,当催化剂c_(M)/c_(A)小于0.037时,反应过程由金属中心数量控制,产生大量多支链异构体产物和裂化产物;当c_(M)/c_(A)大于0.285时,反应过程由酸中心数量控制,有氢解反应发生。在反应压力为0.4 MPa、反应温度为207℃、质量空速为1.0 h^(-1)、氢/烃摩尔比为5、催化剂质量为1.0 g的条件下,当催化剂c_(M)/c_(A)为0.266、正庚烷转化率为70.75%时,异构体总选择性为95.14%,总收率为67.31%,其中多支链异构体收率为15.63%,裂化产物收率低于5%。

Deactivation mechanism of acetone to isobutene conversion over Y/Beta catalyst

The conversion of acetone derived from biomass to isobutene has attracted extensive attentions.In comparison with Brønsted acidic catalyst,Lewis acidic catalyst could exhibit a better catalytic performance with a higher isobutene selectivity.However,the catalyst stability remains a key problem for the long-running acetone conversion and the reasons for catalyst deactivation are poorly understood up to now.Herein,the deactivation mechanism of Lewis acidic Y/Beta catalyst during the acetone to isobutene conversion was investigated by various characterization techniques,including acetone-temperature-programmed surface reaction,gas chromatography-mass spectrometry,in situ ultraviolet-visible,and ^(13)C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy.A successive aldol condensation and cyclization were observed as the main side-reactions during the acetone conversion at Lewis acidic Y sites.In comparison with the low reaction temperature,a rapid formation and accumulation of the larger cyclic unsaturated aldehydes/ketones and aromatics could be observed,and which could strongly adsorb on the Lewis acidic sites,and thus cause the catalyst deactivation eventually.After a simple calcination,the coke deposits could be easily removed and the catalytic activity could be well restored.