Liquid-phase esterification of methacrylic acid with methanol catalyzed by cation-exchange resin in a fixed bed reactor:Experimental and kinetic studies

The kinetic behavior of esterification between methacrylic acid and methanol catalyzed by NKC-9 resin was studied in a fixed bed reactor.The reaction was conducted in the temperature range of 323.15 to 368.15 K with the molar ratio of reactants from 0.8 to 1.4 under certain pressure.The measurement data were regression with the pseudo-homogeneous(P-H),Eley-Rideal(E-R),and Langmuir-Hinshelwood(L-H)heterogeneous kinetic models.Independent adsorption experiments were implemented to gain the adsorption equilibrium constants of four components.Among the above three models,the L-H model exhibited the best fitting results.The stability of NKC-9 was evaluated by long-term running with the yield of methyl methacrylate no decrease during 3000 h operation.The structure and physicochemical properties of the new and used catalyst were performed by several characterizations including thermogravimetric analysis(TG),scanning electron microscope(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR)and so on.

Denatured Thermodynamics of Proteins in Weak Cation-exchange Chromatography

The thermostability of some proteins in weak cation-exchange chromatography was investigated at 20-80 ℃. The results show that there is a fixed thermal denaturation transition temperature for each protein. The appearance of the thermal transition temperature indicates that the conformations of the proteins are destroyed seriously. The thermal behavior of the proteins in weak cation-exchange and hydrophobic interaction chromatographies were compared in a wide temperature range. It was found that the proteins have a higher thermostability in a weak cation-exchange chromatography system. The thermodynamic parameters(Δ H 0, Δ S 0) of those proteins were determined by means of Vant Hoff relationship(ln k -1/ T ). According to standard entropy change(Δ S 0), the conformational change of the proteins was judged in the chromatographic process. The linear relationships between Δ H 0 and Δ S 0 can be used to evaluate 'compensation temperature'( β ) at the protein denaturation and identify the identity of the protein retention mechanism in weak cation-exchange chromatography.

Elution Behaviour of Monocarboxylic Acids on a Cation-exchange Resin Column

The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, Kd, dissociation constant, Aa, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.

Impact of Hydrogen Ion Concentration on Amino Acids Composition of Macadamia Protein: Approached Using Cation-Exchange Chromatography

In the present context, the objective of this study was to synthesize and analyze the content of AA of macadamia protein and the impact of hydrogen ion concentration (pH) on AA composition. The determination of AA mainly by cation-exchange chromatography was also investigated. Reproducible and reliable techniques for quantification and identification of AA usually require derivatization. However, techniques such as AA analyzer are composed of cation-exchange chromatography and other components can sideline the derivatization with significant accuracy. The present analysis revealed a higher concentration of essential amino acids especially acidic AA, Glu and Asp and basic AA, Arg than other AA in macadamia protein. The study constitutes first report of use of bubble chart for evaluation of AA and explaination of AAS. The results may elaborate that the degradation of AA of macadamia protein for extraction of pH 11 is caused by the impact of pH. Moreover, the nutritional values of AA present in macadamia protein could change for the better by adjusting pH of extraction.

Transport Properties of Novel Hybrid Cation-Exchange Membranes on the Base of MF-4SC and Halloysite Nanotubes

The diffusion permeability through new hybrid materials based on a Nafion-type membrane (MF- 4SC) and nanotubes of halloysite is investigated using the Nernst-Planck approach. A method of quantitative evaluation of physicochemical parameters (averaged and individual diffusion coefficients and averaged distribution coefficients of ion pairs in the membrane) of system “electrolyte solution—ion-exchange membrane—water”, which was proposed earlier, is further developed. The parameters of hybrid membranes on the base of MF-4SC and nanotubes of halloysite (5% wt and 8% wt) are obtained from experimental data on diffusion permeability of NaCl solutions using theoretical calculations. New model of three-layer membrane system can be used for refining calculated results with taking into account both diffusive layers. It is shown that adding of halloysite nanotubes into the membrane volume noticeably affects exchange capacity as well as structural and transport characteristics of original perfluorinated membranes. Hybrid membranes on the base of MF-4SC and halloysite nanotubes can be used in fuel cells and catalysis.

Numerical Simulation of Droplets Interacting with a Microcolumnar Solid Structure

The VOF method is used to simulate the dynamics of a droplet interacting with a structure consisting of an array of microcolumns mounted on a flat surface.Such a specific configuration is intended to mimic the typical properties of lotus leaves,which typically display regularly arranged micron-scale papillary structures.After setting the initial velocity of the simulated droplet on the basis of practical considerations,an analysis is conducted about the effect of the characteristic size of the microstructure on the apparent contact angle.The pressure variation in the microstructure caves is also examined.The simulation results show that the change of the contact angle of the droplet in the quasi-static state is consistent with theoretical calculations and the contact angle in the dynamic state is smaller than that in the quasi-static state.Moreover,under dynamic conditions,the pressure fluctuation in the microstructure cave depends essentially on the characteristic size of the microstructure.

Ax22亚型导致家族性血型鉴定错误的研究

目的通过对ABO血型为Ax22/B型的患者及其家属因A亚型造成血清学血型鉴定错误的案例进行分析,总结ABO血型鉴定过程中的注意事项及A亚型的输血策略。方法分别选取A、B两种不同厂家的微柱凝胶血型鉴定卡及试管法在常温和4℃孵育10 min两种条件下对患者及其子女进行血清学血型鉴定;对所有标本进行吸收放散试验及血型基因鉴定;分别用微柱凝胶法和聚凝胺法对同一组标本进行交叉配血。结果B试剂卡凝集强度明显高于A试剂卡,且正定型B试剂卡可以在常温下检测到A抗原,A试剂卡仅在4℃孵育10 min后才可检测到A抗原。试管法血型可明确显示A亚型的反应格局。吸收放散试验显示所有标本红细胞表面均存在A抗原,经基因测序患者为Ax22/B.01,其子女基因型为Ax22/O.01.01。微柱凝胶法交叉配血相合,聚凝胺法镜下可见细胞凝集,交叉配血不合。结论Ax22会造成检测结果假阴性,如正反定型不一致或者对检测结果有任何疑问,应选用试管法或其他检测系统进行复核,必要时进行基因检测;Ax22亚型在配血时有假阴性的可能,有较高的输血风险。

微柱凝胶技术与凝聚胺技术在ABO新生儿溶血病输血前检测中应用对比

目的对比分析微柱凝胶技术与凝聚胺技术在ABO新生儿溶血病输血前检测中的应用。方法将郑州市第一人民医院2020年1月至2023年5月ABO新生儿溶血病患儿(88例)作为研究对象,依据区间随机法将其分为对照组、研究组,各纳入44例,对照组行输血治疗前开展凝聚胺技术检验血型配血,研究组输血治疗前开展微柱凝胶技术检验血型配血。比较两组检验符合率、一次性交叉配血成功率。结果研究组正定型、反定型符合率(100.00%、100.00%)均高于对照组(86.36%、86.36%),两组差异有统计学意义(P<0.05);研究组交叉配血成功率(100.00%)高于对照组(86.36%),两组差异有统计学意义(P<0.05)。结论对比凝聚胺技术,微柱凝胶技术在ABO新生儿溶血病输血前检测中的应用价值更高,有利于提升输血安全,值得应用。

AB血浆倍比稀释在高效价自身抗体患者抗体筛查中的应用研究

目的探讨用AB血浆倍比稀释是否可替代盐水法进行同种抗体效价检测,并消除高效价自身抗体影响,检出同种抗体。方法选取四组标本进行检测:①6例自身抗体标本;②16例已知同种抗体的标本;③16例同种抗体+自身抗体混样标本(人为将6例自身抗体血浆和16例同种抗体血浆混合配成);④4例自身抗体且分别存在抗-C、抗-E、抗-Jka、抗-cE的受血者标本。对①②③组标本分别用盐水、AB血浆分别进行倍比稀释,用抗人球蛋白试验(微柱法)测效价,对④组标本用AB血浆稀释,用抗人球蛋白试验(微柱法)进行不规则抗体筛查。结果①组6例自身抗体标本用盐水倍比稀释法,效价均≥512,用AB血浆倍比稀释法,效价均≤4;②组仅一例效价为2的抗-M结果不一致,盐水稀释法为2,AB血浆稀释法为4,效价≥4时两者结果一致;③组用盐水法与AB血浆稀释法,在效价≥16时,两种方法结果无差异。效价<16时,盐水倍比稀释后效价均为16;AB血浆稀释法,同种抗体效价≥8时,可检出与原同种抗体效价一致,效价≤4时无法分辨同种抗体和自身抗体。④组分别存在抗-C、抗-E、抗-Jka、抗-cE抗体的四个含有自身抗体的受血者在AB血浆倍比稀释试验中,在1∶8效价试管中出现符合相应抗体筛查反应格局变化。结论在高效价自身抗体存在时盐水倍比稀释法极高,AB血浆倍比稀释法能消除1∶4效价试管后自身抗体的影响;AB血浆为倍比稀释液不影响同种抗体的效价检测,且略优于盐水倍比稀释法;AB血浆倍比稀释在高效价自身抗体存在的情况下,可根据三系抗体筛查格局的不同变化检出效价≥8的同种抗体存在,是一种较为简单的可避免自身抗体干扰的免疫血液学实验方法。

AB亚型漏检后A型血浆置换引起可疑溶血分析

目的对1例ABw亚型患者进行A型血浆置换后血型血清学变化以及是否发生溶血反应进行回顾性调查。方法使用微柱凝胶技术、微柱玻璃珠技术、盐水试管法、吸收放散等血型血清学方法及分子生物学方式进行ABO血型鉴定和基因分型,对患者血浆置换前后实验室检查结果进行分析。结果该患者于行2000 mL A型血浆置换后转入本院,d 2检测正反定型相符;d 3检测反定B细胞凝集强度为±~1+,正反定型不符。经试管法、人源抗-B吸收放散试验确认存在B抗原,分子生物学鉴定为ABw03型。患者用A型血浆进行血浆置换后,血红蛋白、血小板计数均一过性下降,肌酐一过性轻度上升,谷丙转氨酶、谷草转氨酶持续下降,总胆红素和间接胆红素一过性下降后上升,提示存在轻微的溶血性输血反应。结论ABO亚型患者含弱A或B抗原,输注大量血浆可能引起溶血性输血反应。应严格按照ABO血型正反定型标准判断血型结果,对弱凝集采取额外实验室检查并结合分子生物学技术进行正确的判断和处理,可以减少ABO亚型的漏检,减少输血反应的发生。

基于空心微柱介电层的柔性电容式压力传感器

提出了一种使用空心微柱介电层的柔性电容式压力传感器,通过倒模的方法制备PDMS和BaTiO_(3)复合材料的空心微柱介电层,通过在PET薄膜上丝网印刷导电银浆制作为阵列式电极。实验表明,该传感器在压力范围为0~5 kPa,5~50 kPa和50~200 kPa时的灵敏度分别为0.498,0.026和0.008 kPa^(-1),最小检测压力可达35 Pa,在1000次重复压力实验中表现稳定,且具有快速的响应速度(约134 ms)。该传感器制备方法简单高效,制作成本低且便于大规模制备,同时该传感器在准确性、稳定性、灵活性等方面都有优秀的表现,可被应用于可穿戴电子设备和智能机器人等领域。

氯离子在局部电化学中对铜电沉积的影响

局部电化学沉积(LECD)制造金属微结构是一种非常便捷和经济的方法。用20μm直径微阳极来研究Cl^(-)浓度在LECD上对铜微柱形貌、直径、沉积速率等的影响。Cl^(-)使铜离子先还原为亚铜离子,然后再还原成铜,能促使铜微柱沉积速率提高,进而可调控铜微柱形貌质量,提高沉积效率。在铜还原过程中氯化亚铜会在铜微柱表面形成,并发生歧化反应,使铜微柱表面产生孔隙、粗糙形貌,而过高Cl^(-)浓度会形成氯化亚铜结晶,增大铜微柱直径。受高电流密度和高氢离子浓度影响,在铜微柱内部无法沉淀氯化亚铜。Cl^(-)浓度所对铜微柱形貌、沉积速率等的影响为Cl^(-)与其它添加剂在LECD上协同应用提供了参考。

凝聚胺法及微柱凝胶法在输血检验中的应用分析

目的分析探究凝聚胺法及微柱凝胶法在输血检验中的应用效果。方法选取2021年5月至2022年5月期间,在我院接受临床输血治疗的240例患者作为研究对象。对所有患者均进行了凝聚胺法和微柱凝胶法的检查,并对比两种方法在检查时间、检验结果以及配血不合的病因方面的差异进行分析和研究。结果根据研究结果,凝聚胺法检验时间明显短于微柱凝胶法。以谱细胞鉴定结果作为金标准,发现微柱凝胶法检出阳性不合格率高于凝聚胺法,差异有统计学意义(P<0.05)。针对凝聚胺法未配血合格的情况,进一步分析发现,血液疾病在不合中占比25.00%,免疫性或溶血性贫血占比12.50%,输血妊娠史血占比12.50%。而在微柱凝胶法配血不合的情况下,血液疾病占比50.00%,免疫性或溶血性贫血占比25.00%,肾病占比12.50%,输血妊娠史血占比12.50%。这表明凝聚胺法和微柱凝胶法在配血不合的病因方面存在一定差异。结论通过研究发现,凝聚胺法的检验时间较短,而微柱凝胶法的阳性不合格检出率较高。综合使用这两种方法可以同时节省时间并提高阳性检出率,从而增加临床输血治疗的安全性。

微柱阵列微通道制造成型及换热性能研究

目的:明确微柱强化微通道流动沸腾换热性能。方法:采用多刀铣削-激光复合加工微柱阵列式微通道,基于高速相机搭建的可视化实验平台,捕捉流动沸腾过程中的流态变化和温度压力等表征参数。结果:不同流速下,与不添加微柱阵列的微通道比较,微柱阵列强化了微通道的换热性能,且不同形状微柱阵列的流态变化和换热性能不同。研究发现微柱阵列能够在一定程度上缓解微通道流动沸腾过程中的不稳定现象,压降波动值降低超过50%。结论:通道植入微柱阵列能够实现强化换热特性要求,并且有效缓解微通道流动不稳定现象,尤其是具有流线型的微柱阵列扰动能力最为显著。

卡式微柱凝胶试验在临床输血检验中的应用价值

目的探讨卡式微柱凝胶试验在临床输血检验中的应用价值。方法收集2022年1—12月沂水县人民医院收治的12例需行输血治疗患者的临床资料,并进行回顾和分析。对所有患者进行低离子凝聚胺技术与卡式微柱凝胶试验交叉配血,分析并比较两种方法的检测结果。结果卡式微柱凝胶试验的主侧和次侧符合率分别为100.00%、91.67%,低离子凝聚胺技术的主侧和次侧符合率均为83.33%,两种方法比较差异无统计学意义(P>0.05)。卡式微柱凝胶试验和低离子凝聚胺技术的检验用时分别为(18.63±1.47)min、(18.48±3.65)min,差异无统计学意义(P>0.05)。卡式微柱凝胶试验的不良反应发生率为8.33%,低于低离子凝聚胺技术(16.67%),但差异无统计学意义(P>0.05)。结论临床输血时需先进行检验,卡式微柱凝胶试验应用效果理想,且安全性较高。

Determination of Trace Non Rare Earth Elements in High Purity Rare Earth Oxides by ICP－AES with Microcolumn Preconcentration in a Flow Injection System

A new method for the determination of trace non-rare earth elements in high purity rare earth oxides by ICP-AES with preconcentration on an active carbon-silica gel microcolumn in a flow injection system is described in this paper. Experimental parameters such as pH, flow rate,reagent concentration,length of reaction coil,eluent acidity,etc. were optimized. In the buffer solution of NH3. H2O/NH4Cl at pH 4. 6,Al,Cr,Cu,Fe, Pb, V and Zn can be preconcentrated and then eluted with 4. 5 mol/L nitric acid utilizing stop-flow technique. The enrichment factors were in range of 8. 1￣12. 6 with detection limits of μg/m level ,and the RSD with metals at μg/g level were 2. 3￣5. 0% (n= 7). The method proposed can reduce the matrix interference effectively , and has been applied to the determination of non-rare earth metals atμg/g level in high purity Eu2O3 with satisfactory results.

微柱凝胶结合抗球蛋白技术检测抗抗生素药物抗体方法建立的探讨

目的探讨建立采用微柱凝胶抗球蛋白检测筛选抗抗生素药物抗体的实验室方法。方法采用微柱凝胶结合抗球蛋白法检测446例使用抗生素患者血浆和红细胞放散液中抗生素药物诱导抗体。结果血浆中共检出75例抗抗生素药物抗体,阳性率分别为头孢哌酮31.25%、哌拉西林18.42%、美罗培南2.44%、头孢噻肟10%、头孢曲松21.43%,美罗培南与其余4种抗生素药物、头孢哌酮与哌拉西林及头孢噻肟、头孢曲松与头孢噻肟,阳性率之间差异有统计学意义(P<0.05)。红细胞DAT阳性率为13%(58例),DAT阳性和阴性的红细胞放散液中抗抗生素抗体阳性率分别为头孢哌酮47.82%和24.72%、哌拉西林46.15%和12.70%、头孢曲松100%和18.52%、头孢噻肟10%和10%;前3者在DAT阳性红细胞放散液中的抗生素药物抗体的阳性率明显高于后者(P<0.05)。结论无论直接抗球蛋白阳性与否,微柱凝胶结合抗球蛋白检测技术适用临床对于使用抗菌药物患者的血浆或红细胞放散液中的药物性抗体的检测。

微柱凝胶免疫分析技术检测孕妇IgG抗体亚型在评估新生儿溶血症中的应用

目的:观察微柱凝胶免疫分析技术检测人IgG抗体亚型在评估新生儿溶血症(HDN)发生的应用效果。方法:选取2022年1月-2022年3月本院行母体抗体效价检测的孕妇50例,O型孕妇42例、Rh阴性孕妇8例,采用自主研发的微柱凝胶免疫分析技术对其IgG抗体亚型进行检测,根据孕妇总IgG抗体效价分组,效价<256纳入低效价组(n=19),≥256纳入高效价组(n=31)。检测各组孕妇血清中致敏抗体IgG亚型种类和含量,分析其与HDN的相关性。结果:50例中总IgG抗体效价>64有40例占80.0%,以256居多占30.0%。50例中有27例发生HDN(54.0%),且总IgG抗体效价越高HDN发病率越高(P<0.05)。高效价组IgG1含量高于低效价组,IgG3含量低于低效价组(P<0.05);高效价组和低效价组的IgG2、IgG4含量比较无差异(P>0.05);HDN患儿产后3d平均血清胆红素水平为(142.68±11.65)μmol/L,母体IgG1含量为(6.25±0.63)g/L,IgG3含量为(0.34±0.12)g/L。IgG1与新生儿血清胆红素水平呈正相关(r=0.603,P<0.001),IgG3与新生儿血清胆红素水平呈负相关(r=-0.675,P<0.001)。结论:对有溶血风险的孕妇早期行IgG抗体检测有利于HDN的早期诊断,IgG1、IgG3是HDN的主要致敏抗体,其含量与HDN的发病有关。本研究制备的微柱凝胶免疫检测卡可同时检测IgG1与IgG3含量,具有较好的临床实用性。

大高宽比阶梯型铜微柱阵列的制作

基于THB–151N光刻胶的微电铸工艺制作了一种阶梯型铜微柱阵列。针对THB–151N光刻胶显影过程中20μm微盲孔显影困难和底部留膜的问题,提出了一种基于浸没式双向兆声波辅助的显影方法。仿真研究了兆声功率密度和微盲孔深宽比对显影液传质过程的影响。优选了兆声功率密度和微盲孔深宽比,并开展了兆声辅助显影的试验研究。同时,针对THB–151N胶膜因曝光剂量选择不当导致微盲孔侧壁垂直度差的问题,通过光刻试验分析了曝光剂量对微盲孔侧壁垂直度的影响,拟合出曝光剂量与胶膜厚度的经验方程。在上述工艺方法和试验研究的基础上,制作出高度300μm、整体高宽比达15∶1、最小边长20μm、4×6的阶梯型铜微柱阵列。

探讨微柱凝胶法和试管法对诊断新生儿溶血病的影响

目的研究采用微柱凝胶法抗人球蛋白试验和试管法抗人球蛋白试验诊断新生儿溶血病的差异,分析孕妇产前抗体效价与新生儿ABO溶血病(ABO-HDN)的关系。方法收集483例O型孕妇的血清标本(其丈夫血型为非O型),依次使用微柱凝胶法抗人球蛋白试验和试管法抗人球蛋白试验检测其IgG抗A、IgG抗B抗体效价;另外对该483例孕妇的新生儿在出生后分别使用微柱凝胶法抗人球蛋白试验和试管法抗人球蛋白试验进行溶血三项试验(直接抗人球蛋白试验、游离抗体试验和抗体热放散试验),分析两种试验方法检出溶血病的差异,并评价O型孕妇血型抗体效价与ABO-HDN之间的关系。结果483例O型孕妇共娩出34例ABO-HDN患儿,总体ABO-HDN发生率为7.04%。随着产前血型IgG抗体效价升高,新生儿ABO-HDN发病率也逐渐增长。125例疑似HDN病例中溶血三项试验微柱凝胶法阳性率均高于试管法,差异有统计学意义。结论ABO-HDN的发生率和孕妇血型抗体效价的高低呈正相关,孕期定期检测抗体效价可预测ABO-HDN的发生。产后使用微柱凝胶法对新生儿进行溶血三项试验可以早期诊断和评估新生儿溶血状况。