Facile synthesis of hierarchical NaX zeolite from natural kaolinite for efficient Knoevenagel condensation

Zeolite catalysts have found extensive applications in the synthesis of various fine chemicals.However,the micropores of zeolites impose diffusion limitations on bulky molecules,greatly reducing the catalytic efficiency.Herein,we explore an economic and environmentally friendly method for synthesizing hierarchical NaX zeolite that exhibits improved catalytic performance in the Knoevenagel condensation reaction for producing the useful fine chemical 2-cyano-3-phenylacrylate.The synthesis was achieved via a low-temperature activation of kaolinite and subsequent in-situ transformation strategy without any template or seed.Systematic characterizations reveal that the synthesized NaX zeolite has both intercrystalline and intra-crystalline mesopores,smaller crystal size,and larger external specific surface area compared to commercial NaX zeolite.Detailed mechanism investigations show that the inter-crystalline mesopores are generated by stacking smaller crystals formed from in-situ crystallization of the depolymerized kaolinite,and the intra-crystalline mesopores are inherited from the pores in the depolymerized kaolinite.This synthesis strategy provides an energy-saving and effective way to construct hierarchical zeolites,which may gain wide applications in fine chemical manufacturing.

Chromatin condensation but not DNA integrity of pig sperm is greater in the sperm-rich fraction

Background Protamination and condensation of sperm chromatin as well as DNA integrity play an essential role during fertilization and embryo development.In some mammals,like pigs,ejaculates are emitted in three separate fractions:pre-sperm,sperm-rich(SRF)and post sperm-rich(PSRF).These fractions are known to vary in volume,sperm concentration and quality,as well as in the origin and composition of seminal plasma(SP),with differences being also observed within the SRF one.Yet,whether disparities in the DNA integrity and chromatin condensation and pro-tamination of their sperm exist has not been interrogated.Results This study determined chromatin protamination(Chromomycin A3 test,CMA_(3)),condensation(Dibromobi-mane test,DBB),and DNA integrity(Comet assay)in the pig sperm contained in the first 10 m L of the SRF(SRF-P1),the remaining portion of the sperm-rich fraction(SRF-P2),and the post sperm-rich fraction(PSRF).While chromatin protamination was found to be similar between the different ejaculate fractions(P>0.05),chromatin condensation was seen to be greater in SRF-P1 and SRF-P2 than in the PSRF(P=0.018 and P=0.004,respectively).Regarding DNA integrity,no differences between fractions were observed(P>0.05).As the SRF-P1 has the highest sperm concentra-tion and ejaculate fractions are known to differ in antioxidant composition,the oxidative stress index(OSi)in SP,calcu-lated as total oxidant activity divided by total antioxidant capacity,was tested and confirmed to be higher in the SRF-P1 than in SRF-P2 and PSRF(0.42±0.06 vs.0.23±0.09 and 0.08±0.00,respectively;P<0.01);this index,in addition,was observed to be correlated to the sperm concentration of each fraction(Rs=0.973;P<0.001).Conclusion While sperm DNA integrity was not found to differ between ejaculate fractions,SRF-P1 and SRF-P2 were observed to exhibit greater chromatin condensation than the PSRF.This could be related to the OSi of each fraction.

Controllable Condensation of Aromatics and Its Mechanisms in Carbonization

In order to obtain liquefied products with higher yields of aromatic molecules to produce mesophase pitch,a good understanding of the relevant reaction mechanisms is required.Reactive molecular dynamics simulations were used to study the thermal reactions of pyrene,1-methylpyrene,7,8,9,10-tetrahydrobenzopyrene,and mixtures of pyrene with 1-octene,cyclohexene,or styrene.The reactant conversion rates,reaction rates,and product distributions were calculated and compared,and the mechanisms were analyzed and discussed.The results demonstrated that methyl and naphthenic structures in aromatics might improve the conversion rates of reactants in hydrogen transfer processes,but their steric hindrances prohibited the generation of high polymers.The naphthenic structures could generate more free radicals and presented a more obvious inhibition effect on the condensation of polymers compared with the methyl side chains.It was discovered that when different olefins were mixed with pyrene,1-octene primarily underwent pyrolysis reactions,whereas cyclohexene mainly underwent hydrogen transfer reactions with pyrene and styrene,mostly producing superconjugated biradicals through condensation reactions with pyrene.In the mixture systems,the olefins scattered aromatic molecules,hindering the formation of pyrene trimers and higher polymers.According to the reactive molecular dynamics simulations,styrene may enhance the yield of dimer and enable the controlled polycondensation of pyrene.

Supersonic expansion and condensation characteristics of hydrogen gas under different temperature conditions

This paper introduced supersonic expansion liquefaction technology into the field of hydrogen liquefaction.The mathematical model for supersonic condensation of hydrogen gas in a Laval nozzle model was established.The supersonic expansion and condensation characteristics of hydrogen gas under different temperature conditions were investigated.The simulation results show that the droplet number rises rapidly from 0 at the nozzle throat as the inlet temperature increases,and the maximum droplet number generated is 1.339×10^(18)kg^(-1)at inlet temperature of 36.0 K.When hydrogen nucleation occurs,the droplet radius increases significantly and shows a positive correlation with the increase in the inlet temperature,and the maximum droplet radii are 6.667×10^(-8)m,1.043×10^(-7)m,and 1.099×10^(-7)m when the inlet temperature is 36.0 K,36.5 K,and 37.0 K,respectively.The maximum nucleation rate decreases with increasing inlet temperature,and the nucleation region of the Laval nozzle becomes wider.The liquefaction efficiency can be effectively improved by lowering the inlet temperature.This is because a lower inlet temperature provides more subcooling,which allows the hydrogen to reach the thermodynamic conditions required for large-scale condensation more quickly.

Finite-Time Thermodynamic Simulation of Circulating Direct Condensation Heat Recovery on Chillers

A time series model is used in this paper to describe the progress of circulating direct condensation heat recovery of the compound condensing process (CCP) which is made of two water cooling condensing processes in series for a centrifugal chiller in the paper. A finite-time thermodynamics method is used to set up the time series simulation model. As a result, an upper bound of recoverable condensation heat for the compound condensing process is obtained which is in good agreement with experimental result. And the result is valuable and useful to optimization design of condensing heat recovery.

Generalized polynomial chaos expansion by reanalysis using static condensation based on substructuring

This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random inputs.The method consists of a generalized polynomial chaos expansion(GPCE)for statistical moment and reliability analyses associated with the stochastic output and a static reanalysis method to generate the input-output data set.In the reanalysis,we employ substructuring for a structure to isolate its local regions that vary due to random inputs.This allows for avoiding repeated computations of invariant substructures while generating the input-output data set.Combining substructuring with static condensation further improves the computational efficiency of the reanalysis without losing accuracy.Consequently,the GPCE with the static reanalysis method can achieve significant computational saving,thus mitigating the curse of dimensionality to some degree for UQ under high-dimensional inputs.The numerical results obtained from a simple structure indicate that the proposed method for UQ produces accurate solutions more efficiently than the GPCE using full finite element analyses(FEAs).We also demonstrate the efficiency and scalability of the proposed method by executing UQ for a large-scale wing-box structure under ten-dimensional(all-dependent)random inputs.

Reducing Condensation Inside the Photovoltaic(PV)Inverter according to the Effect of Diffusion as a Process of Vapor Transport

A photovoltaic(PV)inverter is a vital component of a photovoltaic(PV)solar system.Photovoltaic(PV)inverter failure can mean a solar system that is no longer functioning.When electronic devices such as photovoltaic(PV)inverter devices are subjected to vapor condensation,a risk could occur.Given the amount of moisture in the air,saturation occurswhen the temperature drops to the dewpoint,and condensationmay formon surfaces.Numerical simulation with“COMSOL Software”is important for obtaining knowledge relevant to preventing condensation by using two steps.At first,the assumption was that the device’s water vapor concentration was homogeneous to evaluate the amount of liquid water accumulated on the internal walls of the photovoltaic(PV)inverter box.Second,by considering the effect of external wind velocity onmoisture transport at the air interface to evaluate water vapor transport outdoors and reduce condensation.General factorial designs are utilized for analyzing the nature of the relationship between the vapor condensation response and the variables.Reducing vapor condensation inside the solar inverter by the effect of external wind speed on diffusion as a process of transporting moister air outside the inverter box is the main solution for this problem.During the movement and assessment of the flow of water vapor,the impact of vapor condensation is reduced.The saturation period was determined by using a Boolean saturation indicator.The saturation indicator was set to 1 when saturation was detected(relative humidity greater than or equal to 1)and 0 otherwise.Calculating the flow and dispersion of moist air as a function of wind speed helped solve the problem.

First and Second Law Analysis of a LiBr-Water Absorption Cycle with Recovering Condensation Heat for Generation

In conventional absorption refrigeration systems(ARS),the heat from the condenser is usually rejected by the environment in place to be used in the system,so recuperating this is a good alternative to enhance the system’s performance.For instance,in this paper,an alternative ARS in which LiBr/Water is used as a refrigerant mixture,where part of condensing heat is recovered via the solution heat recovery generator absorption cycle(HR-ARS)was energy and exergy evaluated.The influence of generator,condenser and evaporator temperatures,as well as the efficiency of the solution heat exchanger on the coefficient of performance,exergy performance and exergy destroyed of the HR-ARS system,were analyzed and compared with the traditional ARS system at the same working conditions.The results showed an increase between 5.8%–6.3%on the COP and 3.7%–9.5%in the exergy efficiency when condenser/absorber temperature was reduced from 40℃ to 30℃.However,when the evaporation temperature rose from 5℃ to 15℃,the COP(coefficient of performance)increased by around 8%,although this could be increased by 2.3%–6.3%if the generator temperature decreases from 100℃ to 80℃.Moreover,the COP and exergetic performance for the HR-ARS is more significant at the lowest generator,condenser and evaporator temperatures,as well as at high efficiency in the solution heat exchanger,in comparison to ARS system.Furthermore,the COP and exergy performance for the HR-ARS system was improved by 2.57%to 3.11%and 0.22%to 0.7%,respectively,while the recovering condensation heat for generation is around 1.51%–3.76%lower than with the ARS.It also was found that for all ranges of evaporator and condenser temperatures,the COP for the HR-ARS system is around 3%higher than that obtained with the ARS at the three different generator temperatures here analyzed,while when the solution heat exchanger effectiveness was increased from 0.7–1.0,the total exergy destruction for the HR-ARS resulted be 3.24%–5.01%smaller than the ARS system.Finally,it can be concluded that the components with the most exergy destroyed in the systems(80%to 94%)are the generator and absorber.

New Strategy Leverages Lignin Condensation for Biomass Utilization

There is an old saying in the biorefining industry that“You can make anything from lignin except money.”This bio-based compound is abundant and full of potential,but commercializing it remains a challenge.This may no longer be the case soon with an innovative approach by chemists from the Dalian Institute of Chemical Physics(DICP)of the Chinese Academy of Sciences and their colleagues to harness lignin condensation–often considered a nuisance–for efficient utilization of lignocellulose.

自旋-轨道耦合作用下极化激元凝聚中的调制不稳定性

利用线性稳定性分析方法,对存在自旋-轨道耦合(SOS)作用的二维极化激元玻色-爱因斯坦凝聚(BEC)系统中的调制不稳定性(MI)进行了研究.分析了组分内部,组分之间以及SOC相互作用对系统调制不稳定性的影响.结果显示,当系统内部不存在SOC作用,组分之间的相互作用为0,组分内部存在排斥作用时,不会出现调制不稳定性,组分内部存在吸引作用时,会出现调制不稳定性,并且调制不稳定性区间长度随吸引作用的增强而增加;组分之间相互作用不为0时,组分之间的相互作用以平方形式出现,其正负不会对调制不稳定性产生实质性影响.存在SOC相互作用时,SOC相互作用会引起增益谱曲线的不规则振荡,破坏原来的调制不稳定性区间.

VEGF与ILK在SACC中的表达及相关性研究

目的观察血管内皮生长因子(Vascular endothelial growth factor,VEGF)与整合素连接激酶(Integrin-linked kinase,ILK)在涎腺腺样囊性癌(Salivary adenoid cystic carcinoma,SACC)中的定位及表达,探讨VEGF与ILK在SACC中的作用,揭示SACC的发病机制.方法对30例SACC存档蜡块行免疫组化分析,观察VEGF与ILK在SACC中的表达分布情况.利用SPSS 13.0统计软件分析VEGF与ILK的差异性及相关性.结果在SACC中,VEGF阳性率为83.33%,ILK阳性率为76.67%;VEGF实验组与对照组比较,P<0.05,ILK实验组与对照组比较,P<0.05;VEGF与ILK在SACC中的表达存在正相关,r=0.388.结论在SACC的发生发展过程中,血管生成是其发生的重要步骤,血管的生长速率是其侵袭和转移的条件.VEGF与ILK在血管的生成过程中起着重要的作用,VEGF与ILK在SACC中的表达存在正性相关,它们共同作用于SACC的血管生成,影响SACC血管生长的速率.

姜黄素与β-榄香稀联用对涎腺腺样囊性癌细胞株SACC-LM生长抑制和凋亡的协同作用

[目的]研究姜黄素与β-榄香稀联合对体外培养涎腺腺样囊性癌细胞株SACC-LM生长抑制和凋亡的情况。[方法]应用MTT测定法、流式细胞术和透射电镜观察等方法观察姜黄素协同β-榄香稀(浓度比1∶1)诱导SACC-LM细胞凋亡率及凋亡方式。[结果]1)用MTT测定法,姜黄素协同β-榄香稀(浓度比1∶1)作用SACC-LM细胞24 h后,其抑制率有明显协同效应。2)联合用药对SACC-LM肿瘤细胞Caspase-3的表达阳性率为(46.2±3.2)%明显高于单独用药组。3)用流式细胞术,10μg/mL姜黄素与10μg/mLβ-榄香稀联合作用SACC-LM细胞24 h后诱导SACC-LM细胞发生凋亡,并将细胞周期阻滞于S期。4)用透射电镜观察,协同用药(浓度比1∶1)作用SACC-LM细胞24 h后,出现明显细胞凋亡特征。[结论]姜黄素和β-榄香稀(浓度比1∶1)联合应用可增强对SACC-LM细胞株的敏感作用,并诱导其产生凋亡,使其细胞周期阻滞于S期。

基于均值移动确定性漂移的改进CONDENSATION人脸跟踪

针对视频序列目标跟踪粒子滤波经典CONDENSATION算法用先验转移概率,即采用一阶或二阶AR模型难以有效进行粒子传播的问题,提出了一种改进的CONDENSATION人脸跟踪算法。首先利用高效的均值移动跟踪器以低廉的计算成本初步进行人脸目标跟踪定位,并用此初步跟踪结果来确定CONDENSATION粒子动态传播模型中的确定性漂移部分,然后只需加入一个较小的随机扩散噪声来完成粒子的传播。由于这样所得的粒子点能较为集中地分布在状态的真实区域附近,因而大大提高了粒子的利用效率。人脸跟踪实验表明,该改进算法的性能明显优于原CONDENSATION方法。

Magnesium vapor nucleation in phase transitions and condensation under vacuum conditions

Recent findings related to coagulable magnesium vapor nucleation and growth in vacuum were assessed critically, with emphasis on understanding these processes at a fundamental molecular level. The effects of magnesium vapor pressure, condensation temperature, and condensation zone temperature gradient on magnesium vapor nucleation in phase transitions and condensation from atomic collision and coacervation with collision under vacuum conditions were discussed. Magnesium powder and magnesium lump condensates were produced under different conditions and characterized by scanning electron microscopy （SEM） and energy-dispersive X-ray spectroscopy （EDS）. The right condensation zone temperature approach to the liquid transition primarily improved the magnesium vapor concentration rate. The gas-solid phase transition was primarily inhibited by setting a small condenser temperature gradient. Under the right condensation temperature and temperature gradients, increasing magnesium vapor partial pressure improved crystallization and reduced the oxidation rate.

强力霉素对腺样囊性癌细胞系SAcc83增殖及侵袭行为的影响

目的 :研究强力霉素对腺样囊性癌细胞增殖、 型胶原酶活性及侵袭行为的影响。方法 :采用 MTT法研究不同浓度的强力霉素对 SAcc83细胞增殖的影响 ,明胶底物 SDS- PAGE凝胶电泳检查 型胶原酶活性 ,单层细胞器官培养进行细胞侵袭研究。结果 :不同浓度的强力霉素抑制了 SAcc83细胞的增殖 ,同时它也抑制了 型胶原酶 (MMP- 2 )活性和肿瘤细胞的侵袭。结论 :强力霉素对 SAcc83细胞的增殖具有抑制作用 ,同时也可抑制肿瘤细胞的侵袭 。

黏着斑激酶和细胞外信号调节激酶在SACC-LM和SACC-83细胞中的表达及其意义

目的:检测黏着斑激酶(FAK)及细胞外信号调节激酶(ERK)在涎腺腺样囊性癌(SACC)细胞系SACC-LM和SACC-83中的表达,探讨其与SACC肺转移发生的关系。方法:选择停止在G1/S期的SACC-LM和SACC-83细胞,测定其细胞内FAK和ERK酶活力,采用Western blotting方法检测SACC-LM及SACC-83细胞中FAK及ERK蛋白表达,对其结果进行量化分析。结果:FAK及ERK在SACC-LM细胞中的活性均高于SACC-83细胞(P<0.01),SACC-LM细胞中FAK酶活性与ERK酶活性呈正相关关系(r=0.62,P<0.05)。Western blotting方法检测到在SACC-LM细胞中两种蛋白的表达水平均高于在SACC-83细胞中的表达水平(P<0.05)。结论:FAK及ERK可能参与了SACC的发生发展过程和转移信号转导通路,FAK及ERK蛋白表达变化与SACC的转移行为有关。

单次不同X线剂量照射对SACC-83细胞的放射生物学效应

目的 了解体外培养的SACC-83细胞对不同剂量X线照射的反应。方法 采用SACC-83细胞系,于体外分别给予 2Gy、5Gy、lOGy、15Gy、20Gy、25Gy和 30Gy的X线照射,进行集落细胞数、集落形成率、凋亡DNA电泳梯状图谱、流式细胞仪凋亡率的检测和细胞形态学观察。结果 对照组细胞倍增迅速,2Gy、5Gy、l0Gy细胞增殖缓慢, 15Gy以上的其余各组细胞未见增殖;集落形成率检测显示, 15Gy以上剂量照射各组均为 0. 2~15Gy照射能检测到凋亡带, 15Gy以上为明显的坏死带。15Gy已达体外SACC-83细胞的致死剂量。在形态学上 20~30Gy为坏死,在 10Gy^15Gy为凋亡与坏死的过渡区,在l0Gy剂量时表现为单纯的细胞凋亡, 2~5Gy表现为凋亡细胞与活细胞同时并存。经 2, 5Gy剂量照射细胞主要表现为S期细胞的比例减少,G2 /M期细胞的比例增多,经 10、15、2OGy剂量照射细胞主要表现为S期细胞和G2 /M期细胞的比例均减少。结论 通过SACC-83建立的射线细胞模型,提示在单次连续低剂量的放射线作用下表现为凋亡和活细胞共存,随着放射剂量的增加为凋亡,进而为凋亡和坏死并存,大剂量时,为细胞的坏死,这说明放射线对腺样囊性癌的作用为致细胞凋亡和直接细胞毒作用。照射剂量不同可能引起不同时相的细胞发生凋亡。

Amine-grafted on lanthanide metal-organic frameworks:Three solid base catalysts for Knoevenagel condensation reaction

A post-synthetic modification strategy has been used to prepare three solid base catalysts, including Er（btc）（ED）075（H2O）0.25 （2, btc = 1,3,5-benzenetricarboxylates, ED = 1,2-ethanediamine）, Er（btc）（PP）0.55（H20）0.45 （3, PP = piperazine）, and Er（btc）（DABCO）0.15（H2O）0.85 （4, DABCO = 1,4- diazabicyclo[2.2.2]octane）, by grafting three different diamines onto the coordinatively unsaturated Er（III） ions into the channels of the desolvated lanthanide metal-organic framework （Er（otc））. The resulting metal-organic frameworks were characterized by elemental analysis, thermogravimetric analysis, powder X-ray diffraction, and N2 adsorption. Based on its higher loading ratio of the diamine, as well as its greater stability and porosity, catalyst 2 exhibited higher catalytic activity and reusability than catalysts 3 and 4- for the Knoevenagel condensation reaction. The catalytic mechanism of 2 has also been investigated using size-selective catalysis tests.

阿霉素诱导SACC-83细胞凋亡的试验研究

目的:探讨阿霉素诱导腺样囊性癌细胞凋亡的最佳剂量。方法:采用SACC-83细胞系,于体外分别以含有5μg/ml、10μg/ml、20μg/ml阿霉素的培养液处理12小时后,进行凋亡DNA电泳梯状图谱、流式细胞仪凋亡率的检测和细胞形态学分析。结果:5μg/ml、10μg/ml组细胞检测到凋亡带,而20μg/ml组可见明显的坏死带。形态学上看到20μg/ml组主要表现为坏死;10μg/ml凋亡与坏死同时存在,;5μg/ml时表现为单纯的细胞凋亡。流式细胞仪检测结果发现,在5μg/ml浓度阿霉素作用下,凋亡细胞可达68.46%与其它组相比有显著性差异(P<0.01)。结论:通过阿霉素诱导SACC-83细胞建立凋亡模型,检测发现阿霉素5μg/ml作用下可得到较高含量的凋亡细胞。

一种改进的Condensation人脸特征点跟踪算法

Condensation跟踪算法只能完成一些简单的目标跟踪。由于人脸容易出现被遮挡,姿态和表情也经常发生变化,导致人脸特征点极易跟踪失败。针对这些复杂变化,提出一种改进的Condensation人脸特征点跟踪算法。该算法对跟踪的特征点利用增量PCA方法实现特征基和均值的在线更新,同时,加入一个遗忘因子,使得在新样本的更新过程中,考虑了旧样本的存在,更新了均值。实验证明,该算法可以有效地克服复杂变化带来的影响,实现了人脸特征点的准确跟踪。