Binding tendency with oligonucleotides and cell toxicity of cetyltrimethyl ammonium bromide-coated single-walled carbon nanotubes

Functionalized carbon nanotubes （CNTs） were made for the delivery of genes and drugs and CNT-based biosensors. The basis of CNTs is for binding with biomolecules in biomedical applications. The binding tendency with small interfering RNA oligonucleotides and cytotoxicity of cetyltrimethyl ammonium bromide （CTAB）-coated single-walled carbon nanotubes （SWNTs） were studied. The field emission scanning electron microscopy and transmission electron microscopy results show that a SWNT suspension in CTAB solution was well-dispersed and stable. CTAB is the cross-linker between SWNTs and oligonucleotides. The CTAB-coated SWNTs have less cytotoxicity to human umbilical vein endothelial cells than single SWNTs and the cytotoxicity of CTAB-coated SWNTs depended on the concentration of CTAB-coated SWNTs.

CO_2 capture from binary mixture via forming hydrate with the help of tetra-n-butyl ammonium bromide

Hydrate formation rate and separation effect on the capture of CO2 from binary mixture via forming hydrate with 5 wt% tetra-n-butyl ammonium bromide （TBAB） solution were studied. The results showed that the induction time was 5 min, and the hydrate formation process finished in 1 h at 4.5 ℃ and 4.01 MPa. The hydrate formation rate constant reached the maximum of 1.84× 10^-7 molZ/（s.J） with the feed pressure of 7.30 MPa. The CO2 recovery was about 45 % in the feed pressure range from 4.30 to 7.30 MPa. Under the feed pressure of 4.30 MPa, the maximum separation factor and CO2 concentration in hydrate phase were 7.3 and 38.2 mol%, respectively. The results demonstrated that TBAB accelerated hydrate formation and enriched CO2 in hydrate phase under the gentle condition.

Cytotoxicity effect assessment of acid purified carbon nanotubes modified with cetyltrimethyl ammonium bromide

The cytotoxicities of single-walled carbon nanotubes （SWNTs） and acid purified single-walled carbon nanotubes （SWNT-COOH） were investigated by spectroscopic analysis. Cell viability and cell apoptosis were applied to assessing the cytotoxicity of SWNT-COOH, cetyltrimethyl ammonium bromide （CTAB） and acid purified carbon nanotubes modified with cetyltrimethyl ammonium bromide （SWNT-COOH/CTAB）. The results indicate that SWNTs are more toxic than SWNT-COOH. Concentration and time-curve analyses indicate that cytotoxicity of SWNT-COOH/CTAB is more related to the toxicity of the surfactant CTAB. The cytotoxicity effect of CTAB and SWNT-COOH/CTAB is acceptable at low concentrations （0.5-25μg/mL）. The cytotoxicity observation suggests that SWNT-COOH/CTAB can safely applied to biomedical field at low concentrations （0.5-25μg/mL）.

Modeling phase equilibria of semiclathrate hydrates of CH_4,CO_2 and N_2 in aqueous solution of tetra-n-butyl ammonium bromide

Semiclathrate hydrates of tetra-n-butyl ammonium bromide （TBAB） offer potential solution for gas storage, transportation, separation of flue gases and CO2 sequestration. Models for phase equilibria for these systems have not yet been developed in open literatures and thus require urgent attention. In this work, the first attempt has been made to model phase equilibria of semiclathrate hydrates of CH4, CO2 and N2 in aqueous solution of TBAB. A thermodynamic model for gas hydrate system as proposed by Chen and Guo has been extended for semiclathrate hydrates of gases in aqueous solution of TBAB. A correlation for the activity of water relating to the system temperature, concentration of TBAB in the system and the nature of guest gas molecule has been proposed. The model results have been validated against available experimental data on phase equilibria of semiclathrate hydrate systems of aqueous TBAB with different gases as guest molecule. The extended Chen and Guo＇s model is found to be suitable to explain the promotion effect of TBAB for the studied gaseous system such as, methane, carbon dioxide and nitrogen as a guest molecule. Additionally, a correlation for the increase in equilibrium formation temperature （hydrate promotion temperature, ATp） of semiclathrate hydrate system with respect to pure gas hydrate system has been developed and applied to semiclathrate hydrate of TBAB with several gases as guest molecules. The developed correlation is found to predict the promotion effect satisfactorily for the system studied.

Electrodeposition of cobalt from aqueous sulphate solutions in the presence of tetra ethyl ammonium bromide

The effect of tetra ethyl ammonium bromide （TEAB） as an additive on the structural, morphological characteristics of the cobalt metal produced from aqueous sulphate solutions was investigated. The concentration of TEAB was varied in a range of 1-50 mg/L to evaluate its effect on current efficiency, energy consumption and quality of electrodeposited cobalt metal. Smooth and bright deposits of cobalt were obtained at low concentration of TEAB （10 mg/L） maintaining a current efficiency of 99.6%, with a low energy consumption of 2.38 kW＇h/kg. X-ray diffraction studies reveal that （100） plane is the most preferred plane of crystal growth during cobalt electrodeposition. Scanning electron micrographs indicate that smooth and uniform deposit of cobalt is obtained at 10 mg/L beyond which the deposit quality deteriorates. Cyclic voltammetric studies indicate that the presence of TEAB in the electrolytic bath polarizes the cathode and decreases the cathodic current considerably. XPS results confirm the electrodeposition of high pure cobalt with no sign of chemical bonding with TEAB as evident from the FTIR spectra.

Interactions of Cationic Surfactant Cetyl-trimethyl ammonium bromide with Ammonium nitrate:Surface and Thermodynamic Studies

The study of interactions between surfactant and salt in aqueous solutions has attracted significant interest in recent years because of their widespread applications and relatively complex behavior.This work reports the systematic study of surface phenomenon and self-aggregation behavior of cationic surfactant cetyltrimethyl ammonium bromide(CTAB)with ammonium nitrate(NH_(4)NO_(3))salt.Surface and thermodynamic properties of cationic surfactant CTAB with NH_(4)NO_(3)were investigated at different temperatures using different techniques such as conductometry and surface tensiometery.The surface tension measurement was carried out to find out the critical micelle concentration,free energy of adsorption,free energy of micellization,minimum area per molecule,and surface excess concentration.The study reveals that the process of micellization is spontaneous and exothermic in nature.Conductance measurement was carried out to determine critical micelle concentration,degree of ionization and degree of counter ion binding.Addition of NH_(4)NO_(3)to the surfactant solutions increase the values of degree of ionization and degree of counter ion binding,although it lowers the values of critical micelle concentration showing that the process of micellization is more favorable and spontaneous.The study is very helpful to develop better understanding about interaction between electrolyte and surfactant,which are used in many applications and in different processes(e.g.,pharmaceutical,industrial foaming,drug solubilization,oil recovery,and medium for metal nanoparticle formation).

Organomontmorillonites Modified with 2-Methacryloyloxy Ethyl Alkyl Dimethyl Ammonium Bromide

Organomontmorillonites （organo-MMT） were synthesized by means of montmorillonites （MMT） modified with a series of 2-methacryloyloxy ethyl alkyl dimethyl ammonium bromide （MAAB） having different alkyl chain lengths as cationic surfactants through a cationic exchanging reaction, and were characterized by FTIR, TG, elemental analysis, and XRD. The microenvironment of the organic interlayer such as the orientation and arrangement of the alkyl chains of MAAB, as well as the properties of nanocomposite hydrogels, were also investigated. The amount of organic components absorbed on interlayer and the basal spacing of organo-MMT both increase with the increasing of alkyl length of MAAB. When carbon number of alkyl chain is in the region of 8 to 14, the alkyl chains between layers would adopt a disordered gauche conformation; while the carbon number is 16, an ordered all-trans conformation with a vertical orientation would be found together with the disordered gauche conformation according to the results of XRD and FTIR. Due to the difference of microenvironment of organic interlayer, the Young＇s moduli of the nanocomposite hydrogels increased as the alkyl chains of MAAB became longer.

INTERACTION OF POLY(SODIUM SULFODECYL METHACRYLATE)WITH CETYLTRIMETHYL AMMONIUM BROMIDE IN AQUEOUS SOLUTION

The interaction of poly(sodium sulfodecyl methacrylate) (PSSM) with cetyltrimethyl ammonium bromide (CTAB)was studied. It was found that the precipitate formed from PSSM and CTAB will be dissolved by excessive CTAB, resultingin the appearance of two maxima of the solution viscosity at the molar ratio (CTAB/-SO_3^-) of≈ 0.68 and≈1.30,respectively. The first one is related closely to the aggregation of polymer chains via CTAB molecules and the second oneshould be ascribed to the formation of the mixed micelles comprising surfactant and the polymer's hydrophobic chains. Theeffect of NaCl on the viscosity, the transmittance of the aqueous solution and the solubility of oil-soluble dye (dimethyl yellow) in the mixed system were also investigated.

Facile Bromination of Aromatic Ethers with Quaternary Ammonium Bromide and Iodosylbenzene

Aromatic ethers were conveniently brominated with quaternary ammonium bromide and iodosylbenzene in glacial acetic acid under mild conditions to give the corresponding monobromo-aromatic ethers in nearly quantitative yields.

KOH/NaOH两种碱性体系下合成纳米片层分子筛

以小分子阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)为结构导向剂,在KOH和NaOH 2种碱性体系下水热合成纳米片层分子筛,并分析K^(+)、Na^(+)和Silicalite-1晶种溶胶对合成样品的物相和形貌的影响。结果表明:以KOH为碱源,在添加Silicalite-1晶种溶胶的条件下,水热晶化96 h即可合成高结晶度、纳米薄片沿b轴方向有序堆积多层和随机堆积单层的混合形貌ZSM-5分子筛;以NaOH为碱源,在不添加Silicalite-1晶种溶胶的条件下,水热晶化48 h即可合成高结晶度、由纳米薄片和纳米棒紧密堆积而成的纺锤状聚集体形貌MOR分子筛。研究结果可为进一步优化合成MOR和ZSM-5分子筛纳米片提供思路。

DTAB反胶束萃取花椒籽中蛋白质和油脂研究

利用十二烷基三甲基溴化铵(dodecyl trimethyl ammonium bromide,DTAB)-异辛烷-正己醇反胶束体系,对花椒籽中的蛋白质和油脂同步萃取进行了探究。结果表明,前萃过程油脂直接溶解于有机相中,蛋白质增溶于反胶束极性核中,蛋白质的前萃率受DTAB浓度、萃取时间、缓冲溶液pH值、氯化钠浓度、料液比的影响。随后,反胶束溶液通过加入等体积含有一定离子强度和pH值的水相构筑WinsorⅡ微乳体系来实现蛋白质转移。其蛋白质后萃率和油脂萃取率受后萃水相的酸度和离子强度等因素的影响。

碱处理制备高硅多级孔ZSM-5催化MTP反应

以水热法合成母体硼硅沸石(BS),然后使用氢氧化钠(NaOH)溶液单独处理以及氢氧化钠和十六烷基三甲基溴化铵(CTAB)混合溶液处理,并在碱溶液中加入铝源,制备一系列高硅多级孔ZSM-5分子筛样品(命名为BHZ-A和BHZ-AB系列样品)。采用XRD、SEM、ICP、Ar物理吸附、NH3-TPD和热重分析等手段表征样品的孔结构和酸性质等,并提出了CTAB的保护作用:在碱处理过程中,CTAB抑制NaOH的脱硅作用从而保护分子筛不被过度刻蚀。在压力0.1 MPa、温度743 K、水/醇摩尔比为1/1和甲醇质量空速为3 h^(-1)条件下,采用固定床反应器评价BHZ(含B的H型ZSM-5)分子筛样品催化甲醇制丙烯(MTP)反应72 h的性能。结果表明:通过碱处理制备得到的高硅多级孔ZSM-5分子筛的强酸量是影响其MTP反应性能和积炭的主要因素,由于BHZ-0.1A和BHZ-0.1AB样品具有丰富的介孔和合适的酸性,其MTP反应性能优异,丙烯选择性均约为50%,积炭量均约为1.5%。

格隆溴铵联合异丙托溴铵气道雾化治疗慢性阻塞性肺疾病急性加重期的效果及对免疫功能、通气功能的影响

目的研究格隆溴铵联合异丙托溴铵气道雾化治疗对慢性阻塞性肺疾病急性加重期(AECOPD)的效果及对免疫功能、通气功能的影响。方法前瞻性选取2021年1月至2023年12月西安市长安医院收治的102例AECOPD患者作为研究对象,按照随机数字表法将其分为观察组和对照组,每组各51例。对照组采用异丙托溴铵治疗,观察组采用格隆溴铵联合异丙托溴铵治疗。比较两组的疗效,治疗前、治疗1周后的免疫功能(CD3^(+)、CD4^(+)/CD8^(+)、CD4^(+))、通气功能[最大呼气压(PEmax)、用力肺活量(FVC)、呼气峰流速(PEF)、一氧化碳弥散量(DLCO)和最大吸气压(PImax)]和炎症因子[白细胞介素(IL)-18、高迁移率蛋白1(HMGB1)、IL-32、降钙素原和超敏C反应蛋白(hs-CRP)]指标。结果观察组总有效率为94.12%,显著高于对照组(78.43%),差异有统计学意义(P<0.05)。治疗1周后,观察组的CD3^(+)、CD4^(+)/CD8^(+)、CD4^(+)分别为(71.36±4.28)%、1.06±0.13、(40.59±1.48)%,均高于对照组[(62.52±3.41)%、1.53±0.18、(35.33±1.27)%],差异均有统计学意义(P<0.05)。治疗1周后,观察组的PEmax、FVC、PEF、DLCO、PImax分别为(47.67±4.25)%、(2.78±0.34)L、(1.95±0.26)L/s、(71.36±4.48)mL/min×mmHg、(79.56±6.28)%,均高于对照组[(38.65±2.28)%、(2.07±0.25)L、(1.95±0.26)L/s、(71.36±4.48)mL/min×mmHg、(79.56±6.28)%],差异均有统计学意义(P<0.05)。治疗1周后,两组的血清IL-18、HMGB1、IL-32、降钙素原、hs-CRP水平分别为(22.58±1.34)pg/mL、(46.75±3.89)pg/mL、(19.34±1.25)pg/mL、(0.37±0.09)mg/mL、(1.29±0.27)mg/mL,均低于对照组[(30.45±1.72)pg/mL、(83.42±10.57)pg/mL、(27.59±3.48)pg/mL、(0.94±0.25)pg/mL、(1.83±0.45)mg/mL],差异均有统计学意义(P<0.05)。观察组的皮疹、咽部不适、头晕头痛和胃部不适发生率(19.61%vs.15.69%)比较无差异(P>0.05)。结论格隆溴铵联合异丙托溴铵气道雾化治疗能有效改善AECOPD患者的免疫功能和通气功能,提高疗效,减轻炎症反应,值得推广。

季铵盐类抑菌剂在药物制剂中的应用进展

季铵盐类抑菌剂是一类具有广谱抗菌活性的阳离子抑菌剂,主要包括苯扎氯铵、苯扎溴铵、聚季铵盐-1、苄索氯铵和西曲溴铵等,被广泛作为药物制剂中的抑菌剂或药品生产及医疗环境控制的消毒剂使用。本文对常用的季铵盐类抑菌剂在药物制剂中的使用剂量、应用范围、抑菌性能和安全性等进行综述,以期对该类抑菌剂的性质有更全面的了解,为药物制剂中合理选用季铵盐类抑菌剂提供参考。

三联雾化方案联合支气管镜灌洗在儿童肺炎支原体肺炎中的应用效果

目的:探究三联雾化方案联合支气管镜灌洗在儿童肺炎支原体肺炎(MPP)中的应用效果。方法:选取2022年1月—2023年8月佛山市南海区妇幼保健院收治的92例MPP儿童为研究对象,根据随机数表法分为观察组(n=46)与对照组(n=46)。对照组给予支气管镜灌洗治疗,观察组在对照组基础上增加三联雾化方案(布地奈德、沙丁胺醇、异丙托溴铵)治疗。比较两组临床疗效、临床症状转归情况、住院时间、炎症因子水平、血气指标及不良反应发生情况。结果:观察组治疗后临床疗效总有效率为97.83%,对照组为84.78%,观察组临床疗效总有效率明显比对照组高,差异有统计学意义(P<0.05);观察组发热消退时间、咳嗽消失时间、肺部湿啰音消失时间、平均住院时间均比对照组短,差异有统计学意义(P<0.05);两组治疗后炎症因子白细胞介素-6(IL-6)、C反应蛋白(CRP)、降钙素原(PCT)水平与治疗前相比均降低,且观察组治疗后IL-6、CRP、PCT水平均比对照组低,差异有统计学意义(P<0.05)。两组治疗后血气指标血氧饱和度(SpO2)、动脉血氧分压(PaO2)水平与治疗前相比均升高,二氧化碳分压(PaCO_(2))水平与治疗前相比均降低,且观察组治疗后SpO2、PaO2水平均比对照组高,PaCO_(2)水平比对照组低,差异有统计学意义(P<0.05);观察组治疗期间不良反应总发生率比对照组高,差异无统计学意义(P>0.05)。结论:布地奈德、沙丁胺醇与异丙托溴铵三联雾化联合支气管镜灌洗在儿童MPP治疗中临床效果显著,能有效缩短相关临床症状消失时间及住院时间,减轻炎症反应,改善血气指标,具有一定安全性。

表面活性剂辅助制备(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4)高熵氧化物及储锂性能

为了进一步提高锂离子电池负极材料(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4)高熵氧化物(HEO)的倍率性能,以金属硝酸盐为金属源、尿素为沉淀剂、十二烷基三甲基溴化铵(DTAB)为表面活性剂,利用水热法制备了具有单一尖晶石结构的(Co_(0.2)Cr_(0.2)Fe_(0.2)Mn_(0.2)Ni_(0.2))_(3)O_(4)纳米材料(HEO-DTAB)。采用XRD、SEM、EDS、比表面及孔径分析仪对HEO-DTAB进行了表征,并对其制作的电极进行了电化学性能测试。结果表明,与未添加DTAB制备的材料(HEO)相比,HEO-DTAB具有更小的颗粒尺寸(10.8 nm)、更均匀的分散性、更大的比表面积(27.88 m^(2)/g)和均一的孔结构;HEO-DTAB制作的电极在0.2 A/g下展示了较高的初始放电比容量(1308 mA·h/g)和库仑效率(82.5%),循环25圈时放电比容量为1263 mA·h/g;在1 A/g下,循环150圈后的放电比容量高达1053m A·h/g,是HEO制作的电极的8.4倍。HEO-DTAB的纳米结构使其电极材料具有较大的赝电容贡献率(91.1%,扫描速率为1.5 mV/s),大幅度提升了材料的比容量和倍率性能。

季铵盐类相转移催化剂TPBAB的合成研究及应用

本课题拟采用三正丙胺与溴代正丁烷为主要原料,通过加热-回流-旋转-蒸发-冷却-结晶-干燥-抽滤-过滤等工艺,制备出三丙基丁基溴化铵(TPBAB)相转移催化剂。在实验过程中,对反应溶剂、反应温度、反应时间、物料比、结晶溶剂等条件进行了研究,并利用响应面法确定了合成TPBAB的最佳工艺条件:物料比n(三正丙胺)∶n(溴代正丁烷)=1∶1.1,反应温度80℃,反应时间12 h,反应溶剂乙腈,结晶溶剂乙酸乙酯为最佳合成工艺。用红外光谱、HNMR、HPLC等方法对其进行了定性分析。实验结果表明,所获得的产物确实含有目标物质。通过在诺氟沙星苄基衍生物合成的应用中,证明所得产物具有一定的活性。

孟鲁司特钠联合异丙托溴铵对老年COPD合并肺感染患者的影响分析

分析孟鲁司特钠联合异丙托溴铵对老年慢性阻塞性肺疾病(COPD)合并肺感染患者肺功能、血肌酐及炎性因子的影响。选取2021年7月—2022年7月期间北京市西城区平安医院收治的COPD合并肺感染老年患者112例,按照治疗方式不同将患者分为观察组(孟鲁司特联合异丙托溴铵治疗)与对照组(异丙托溴铵治疗),每组各56例,比较两组患者治疗前后治疗有效率、肺功能、血肌酐及炎性因子指标,以及不良反应发生情况。结果显示,观察组治疗总有效率显著高于对照组(P<0.05);治疗后,观察组一秒率(FEV_(1)/FVC)、第一秒呼气量占预计值百分比(FEV_(1)%pred)和每分钟最大通气量(MVV)均高于对照组,血肌酐水平低于对照组(P<0.05)。研究发现,孟鲁司特钠联合异丙托溴铵对老年COPD合并肺感染患者的疗效更佳,能快速缓解患者体征与临床症状,不良反应发生率低,可以显著改善患者机体的炎性因子水平、肺功能、血肌酐水平,值得临床应用。

Direct synthesis of propylene carbonate from propylene and carbon dioxide catalyzed by quaternary ammonium heteropolyphosphatotungstate–TBAB system

In this paper,we have developed a highly efficient method for the direct preparation of propylene carbonate from propylene and carbon dioxide（CO2） using quaternary ammonium heteropolyphosphatotungstate–quaternary ammonium halide catalytic system with anhydrous hydrogen peroxide as an oxidant through one-pot two-step process.The effects of the amount of tetrabutylammonium bromide（TBAB）,the concentration of hydrogen peroxide and other reaction conditions were investigated.The catalyst system gave an optimum propylene oxide yield（91%） at75°C in oxidation step and the highest propylene carbonate yield（99%） at 140°C and 3.0 MPa in cycloaddition step.Based on the results,a reaction mechanism has been proposed.

Indirect Determination of CTMAB with Sodium Chloride and Ammonium Thiocyanate by Floatation and Separation of Zinc

A new method for indirect determination of cetyl-trimethyl ammonium bromide (CTMAB) with NaCl and NH4SCN by floatation and separation of zinc has been studied. The study shows that Zn(II) can associate with NH4SCN and CTMAB to form insoluble ternary ion-association complex, and the precipitate can float on the surface of the liquid phase. A good linear relationship is observed between the floatation yield (E%) of Zn(II) and the amount of CTMAB. On the ground, CTMAB can be indirectly determined by determining E% of Zn(II). The results were satisfactory.