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Selectedin vitro methods to determine antioxidant activity of hydrophilic/lipophilic substances 测定亲水/亲脂性物质抗氧化活性的体外选择方法
IF 0.8 Pub Date : 2019-10-01 DOI: 10.2478/acs-2019-0028
A. Ácsová, Silvia Martiniaková, J. Hojerová
Abstract The topic of free radicals and related antioxidants is greatly discussed nowadays. Antioxidants help to neutralize free radicals before damaging cells. In the absence of antioxidants, a phenomenon called oxidative stress occurs. Oxidative stress can cause many diseases e.g. Alzheimer’s disease and cardiovascular diseases. Therefore, antioxidant activity of various compounds and the mechanism of their action have to be studied. Antioxidant activity and capacity are measured by in vitro and in vivo methods; in vitro methods are divided into two groups according to chemical reactions between free radicals and antioxidants. The first group is based on the transfer of hydrogen atoms (HAT), the second one on the transfer of electrons (ET). The most frequently used methods in the field of antioxidant power measurement are discussed in this work in terms of their principle, mechanism, methodology, the way of results evaluation and possible pitfalls.
摘要自由基及其相关抗氧化剂是近年来研究的热点。抗氧化剂有助于在破坏细胞之前中和自由基。在缺乏抗氧化剂的情况下,就会出现一种叫做氧化应激的现象。氧化应激可引起许多疾病,如阿尔茨海默病和心血管疾病。因此,必须对各种化合物的抗氧化活性及其作用机制进行研究。通过体外和体内方法测定抗氧化活性和抗氧化能力;根据自由基和抗氧化剂之间的化学反应,体外方法分为两组。第一组是基于氢原子的转移(HAT),第二组是基于电子的转移(ET)。本文讨论了抗氧化能力测定中常用的几种方法的原理、机理、方法、结果评价方法和可能存在的缺陷。
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引用次数: 10
3-Hydroxymethyl-1,4-dihydro-4-oxoquinoline like compound with promising biological and complexing activity 具有良好生物和络合活性的3-羟甲基-1,4-二氢-4-氧喹啉类化合物
IF 0.8 Pub Date : 2019-10-01 DOI: 10.2478/acs-2019-0025
V. Milata, Maroš Bella, Robert Kurinec
Hydroxymethyl group is present in many useful and biologically potent substances like sugars, kojic acid (Bajpai, 1982), ronicol (3-hydroxymethylpyridine) (Moncol, 2006; Broghammer, 1967) or hydroxymethylphenol — intermediate for bakelite (Baekeland, 1909). On the other hand, 4-quinolones are a group of antibacterials with various biological activities if substituted in position 3and they are anti-CNS and similar diseases agents if substituted in position 2(kynurenic acid derivatives) (Turski, 2013; Szalardy, 2012; Fulop, 2009). Considering this, we were interested in the synthesis of 3-hydroxymethyl-1,4dihydro-4-oxoquinoline. 4-Quinolones are a well-known group of chemotherapeutics with a broad spectrum of activities (Andriole, 2000; Milata, 2000) based on inhibition of the enzyme of bacterial topoisomerase II (DNA gyrase) and topoisomerase IV in Gram-positive species, thus inhibiting tertiary negative supercoiling of bacterial DNA (Gellert, 1976; Wang, 1985; Gootz, 1996) mostly bound to oxygen atoms in positions 3and 4of the fused pyrid-4-one-3-carboxylic acid moiety (Andriole, 2000). Therefore, it should be interesting to prepare and evaluate the corresponding structural motif, namely 3-hydroxymethylquinol4-one. Substructural search in database SciFinder provided only various applications of formaldehyde with 4-quinolones or their precursors (Goldsworthy, 1982) but no true synthesis has been reported. Therefore, this compound with promising binding and complexing activity has been prepared.
羟甲基存在于许多有用的和具有生物效力的物质中,如糖、曲酸(Bajpai, 1982)、硝基醇(3-羟甲基吡啶)(Moncol, 2006;Broghammer, 1967)或羟基甲基苯酚-酚醛中间体(Baekeland, 1909)。另一方面,4-喹诺酮类药物如果取代第3位,则是一组具有各种生物活性的抗菌药物,如果取代第2位,则是抗中枢神经系统和类似疾病的药物(犬尿酸衍生物)(Turski, 2013;Szalardy, 2012;费洛浦用,2009)。考虑到这一点,我们对合成3-羟基甲基-1,4二氢-4-氧喹啉很感兴趣。4-喹诺酮类药物是一种众所周知的具有广谱活性的化疗药物(Andriole, 2000;Milata, 2000)基于抑制细菌拓扑异构酶II (DNA旋转酶)和拓扑异构酶IV在革兰氏阳性物种的酶,从而抑制细菌DNA的第三负超卷曲(Gellert, 1976;王,1985;Gootz, 1996),主要与融合吡啶-4- 1 -3-羧酸部分的第3位和第4位氧原子结合(Andriole, 2000)。因此,制备和评价相应的结构基序,即3-羟甲基喹啉- 1是一个值得关注的问题。数据库SciFinder中的亚结构搜索只提供了甲醛与4-喹诺酮类或其前体的各种应用(Goldsworthy, 1982),但没有真正的合成报道。因此,制备了这种具有良好结合和络合活性的化合物。
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引用次数: 0
Slovak natural zeolites as a suitable medium for antibiotics elimination from wastewater 斯洛伐克天然沸石作为去除废水中抗生素的合适介质
IF 0.8 Pub Date : 2019-10-01 DOI: 10.2478/acs-2019-0022
Petra Szabová, Michaela Plekancová, Nikolas Gróf, I. Bodík
Abstract Pharmaceuticals are one of the most used compounds present in various environmental compartments. Due to their high consumption and possible unhealthy effect on ecosystems, pharmaceuticals have been identified as “emerging organic contaminants”. Since these compounds have medium to high polarity, they end up in the water compartment after being used. This work deals with the sorption of three pharmaceutical substances from the therapeutic group of antibiotics. Specifically we have focused on Azithromycin, Clarithromycin and Erythromycin. Three fractions of the natural Slovak zeolites (200 μm, 0.5—1 mm and 1.5—2 mm) were used as the sorption medium. Experimental results have proven very effective sorption of antibiotics by zeolites. Azithromycin removal of over 99 % for all three zeolite fractions from wastewater treatment plant Stupava and wastewater treatment plant Devínska Nová Ves was achieved. Clarithromycin removal of 79 % for fraction 1—2.5 mm, 87.3 % for fraction 0.5—1 mm and of 99.8 % for fraction 200 μm from the effluent of wastewater treatment plant Stupava was observed. Erythromycin removal of 31.3 % for fraction 1—2.5 mm, 66.9 % for fraction 0.5—1mm and of 94.7 % for fraction 200 μm from effluent of wastewater treatment plant Stupava was measured. More than 95 % of Clarithromycin and Erythromycin were eliminated from the effluent of wastewater treatment plant Devínska Nová Ves. The highest elimination percentage was observed for the smallest zeolite fraction due to the highest specific surface area.
摘要药物是存在于各种环境分区中的最常用的化合物之一。由于其高消耗量和可能对生态系统产生的不健康影响,药物被确定为“新兴的有机污染物”。由于这些化合物具有中等到高的极性,它们在使用后最终进入水室。这项工作涉及抗生素治疗组中三种药物的吸附。我们特别关注阿奇霉素、克拉霉素和红霉素。斯洛伐克天然沸石的三个部分(200μm、0.5-1mm和1.5-2mm)用作吸附介质。实验结果证明沸石对抗生素的吸附非常有效。废水处理厂Stupava和废水处理厂Devínska NováVes的所有三种沸石馏分的阿奇霉素去除率均超过99%。从Stupava污水处理厂的出水中观察到,1-2.5mm组分的克拉霉素去除率为79%,0.5-1mm组分为87.3%,200μm组分为99.8%。测定了Stupava污水处理厂出水中1-2.5mm组分的红霉素去除率为31.3%,0.5--1mm组分为66.9%,200μm组分为94.7%。废水处理厂Devínska NováVes的废水中,超过95%的克拉霉素和红霉素被清除。由于最高的比表面积,对于最小的沸石组分观察到最高的消除百分比。
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引用次数: 3
Antioxidant action of phenols: Revisiting theoretical calculations of their thermodynamics 酚类物质的抗氧化作用:对其热力学理论计算的回顾
IF 0.8 Pub Date : 2019-10-01 DOI: 10.2478/acs-2019-0029
Monika Biela, Bernadeta Pelikánová, M. Michalík
Abstract Theoretical prediction ability of M06-2X functional was tested for thermodynamics of phenol, 15 para and 15 meta phenol derivatives. Calculations were done for gas phase as well as for polar and nonpolar solvents. Although predicted values might be shifted from the experimental ones in the framework of the employed DFT functional and basis set, the calculated and experimental data sets correlate well together. Very good linearity was found especially for the correlation of experimental and theoretical proton affinities. Hammett type correlations between the environments considered were compared. The phenolic C—O bond length was also tested as an alternative substituent effect descriptor while the type and position of the functional group on the aromatic ring have a direct effect on the phenolic bond.
对M06-2X官能团对苯酚、15对位苯酚和15间位苯酚衍生物的热力学性质进行了理论预测。对气相以及极性和非极性溶剂进行了计算。尽管在所采用的DFT函数集和基集的框架下,预测值可能会从实验值偏移,但计算数据集和实验数据集之间的相关性很好。发现了非常好的线性,特别是在实验和理论质子亲和力的相关性方面。比较了所考虑的环境之间的Hammett型相关性。酚类C-O键长也被测试为替代取代基效应描述符,而芳环上官能团的类型和位置对酚类键有直接影响。
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引用次数: 4
Steam explosion of wood particles from fibreboard and particle board with indirect control by enzymatic hydrolysis 用酶水解间接控制纤维板和刨花板产生的木颗粒的蒸汽爆炸
IF 0.8 Pub Date : 2019-10-01 DOI: 10.2478/acs-2019-0026
A. Pažitný
Abstract Pretreatment of particles obtained from lignocellulosic materials by steam explosion with indirect control by enzymatic hydrolysis has been studied. The dendromass pretreatment model has been applied for recycled fibreboard and particle board based on softwood. Their structure and chemical composition partly predetermine these lignocellulosic materials consisting of a mixture of spruce and fir particles also for bioethanol production. Optimum steam explosion temperature of 205 °C was determined based on the concentration of total monosaccharides — glucose, xylose and arabinose, among all experimentally prepared hydrolysates. This corresponds to basic conditions for fine disintegration of biomass to lignocellulosic structure with good holocellulose accessibility. Particles obtained from fibreboard and particle board primarily consisting of softwood without steam explosion pretreatment provide relatively low cellulose accessibility for commercial enzymes activity while monosaccharides concentration is partly reduced because of torrefaction at high temperatures. The concentration of monosaccharides in hydrolysates was determined for original sample and each steam explosion temperature. Based on the steam explosion conditions, the effect of severity factors was investigated to find optimum pretreatment conditions to increase accessibility of softwood cellulose and hemicelluloses. The identified optimum severity factor RO = 4.09 matches the optimum steam explosion temperature of 205 °C and the residence time of 10 minutes.
摘要研究了以木质纤维素为原料,采用蒸汽爆破和酶水解间接控制预处理木质纤维素颗粒的方法。将树枝团预处理模型应用于软木再生纤维板和刨花板。它们的结构和化学成分部分预先决定了这些木质纤维素材料,这些材料由云杉和冷杉颗粒的混合物组成,也用于生物乙醇生产。根据所有实验制备的水解产物中总单糖(葡萄糖、木糖和阿拉伯糖)的浓度,确定了205°C的最佳蒸汽爆炸温度。这对应于生物质精细分解为具有良好的全纤维素可及性的木质纤维素结构的基本条件。从纤维板和主要由软木组成的颗粒板获得的颗粒在没有蒸汽爆炸预处理的情况下为商业酶活性提供了相对较低的纤维素可及性,而单糖浓度由于在高温下的烘焙而部分降低。对原始样品和每个蒸汽爆炸温度测定水解产物中单糖的浓度。基于蒸汽爆炸条件,研究了严重性因素的影响,以找到提高软木纤维素和半纤维素可及性的最佳预处理条件。确定的最佳严重性系数RO=4.09与205°C的最佳蒸汽爆炸温度和10分钟的停留时间相匹配。
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引用次数: 4
DFT and ab initio calculations of ionization potentials, proton affinities and bond dissociation enthalpies of aromatic compounds 芳族化合物的电离势、质子亲和和键解离焓的DFT和从头计算
IF 0.8 Pub Date : 2019-10-01 DOI: 10.2478/acs-2019-0032
D. Cagardová, M. Michalík, E. Klein, V. Lukeš, Z. Marković
Abstract Theoretical study of phenol, thiophenol, benzeneselenol, aniline and their para-amino and paranitro derivatives is presented. Neutral molecules, their deprotonated forms, neutral radicals, and radical cations were studied using three Density Functional Theory (DFT) functionals as well as combined DFT and ab initio G4 method in order to calculate the N—H, O—H, S—H, and Se—H bond dissociation enthalpies (BDE), proton affinities of corresponding anions (PA) and ionization potentials (IP) of studied compounds. These quantities represent fundamental reaction enthalpies related to the radical scavenging action of primary antioxidants. Calculated values were compared with available experimental data to assess applicability of the computational approaches employed. M06-2X/6-311++G(d,p) and G4 methods showed the best agreement with the available experimental gas-phase reaction enthalpies.
摘要对苯酚、噻吩、苯二酚、苯胺及其对氨基和对硝基衍生物进行了理论研究。采用密度泛函理论(DFT)三种泛函以及DFT和从头算G4相结合的方法研究了中性分子及其去质子化形式、中性自由基和自由基阳离子,计算了所研究化合物的N-H、O-H、S-H和Se-H键解离焓(BDE)、相应阴离子的质子亲和力(PA)和电离势(IP)。这些量代表与主要抗氧化剂清除自由基作用有关的基本反应焓。将计算值与现有实验数据进行比较,以评估所采用计算方法的适用性。M06-2X/6-311++G(d,p)和G4方法与实验气相反应焓值最吻合。
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引用次数: 3
Corrigendum to: Thermal inactivation kinetics of Aspergillus oryzae β-galactosidase in concentrated lactose solution 勘误表:浓缩乳糖溶液中米曲霉β-半乳糖苷酶的热失活动力学
IF 0.8 Pub Date : 2019-10-01 DOI: 10.2478/ACS-2019-0031
V. Illeová, M. Polakovič
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引用次数: 0
Growth of Staphylococcus aureus 2064 described by predictive microbiology: From primary to secondary models 预测微生物学描述的金黄色葡萄球菌2064的生长:从初级到次级模型
IF 0.8 Pub Date : 2019-10-01 DOI: 10.2478/acs-2019-0024
A. Medveďová, A. Havlíková, Ľ. Valík
Abstract The growth of Staphylococcus aureus 2064 isolate in model nutrient broth was studied as affected by temperature and water activity using principles and models of predictive microbiology. Specific rates resulting from growth curves fitted by the Baranyi model were modelled by the secondary Ratkowsky model for suboptimal temperature range (RTKsub) as well as the Ratkowsky extended model (RTKext) and cardinal model (CM) in the whole temperature range. With the biological background of the RTKext model, cardinal values of temperature Tmin = 6.06 °C and Tmax = 47.9 °C and water activity aw min = 0.859 were calculated and validated with cardinal values estimated by CM (Tmin = 7.72 °C, Tmax = 46.73 °C, aw min = 0.808). CM also provided other cardinal values, Topt = 40.63 °C, aw opt = 0.994, as well as optimal specific growth rate of 1.97 h–1 (at Topt and aw opt). To evaluate the goodness of fit of all models, mathematical and graphical validation was performed and the statistical indices proved appropriateness of all the secondary models used.
摘要应用预测微生物学原理和模型,研究了温度和水分活度对金黄色葡萄球菌2064分离株在模型营养肉汤中生长的影响。Baranyi模型拟合的生长曲线产生的比速率由次优温度范围的二次Ratkowsky模型(RTKsub)以及整个温度范围的Ratkowski扩展模型(RTKext)和基数模型(CM)建模。在RTKext模型的生物学背景下,计算并验证了温度Tmin=6.06°C和Tmax=47.9°C的基本值以及水活度aw-min=0.859,并用CM估计的基本值(Tmin=7.72°C,Tmax=46.73°C,aw-min0.808)进行了验证。CM还提供了其他基本值,Topt=40.63°C,以及1.97 h–1的最佳比生长率(在Topt和aw-opt)。为了评估所有模型的拟合优度,进行了数学和图形验证,统计指标证明了所使用的所有次要模型的适当性。
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引用次数: 2
Neural network based explicit MPC for chemical reactor control 基于神经网络的显式MPC化学反应器控制
IF 0.8 Pub Date : 2019-10-01 DOI: 10.2478/acs-2019-0030
Karol Kiš, Martin Klauco
Abstract In this paper, implementation of deep neural networks applied in process control is presented. In our approach, training of the neural network is based on model predictive control, which is popular for its ability to be tuned by the weighting matrices and for it respecting the system constraints. A neural network that can approximate the MPC behavior by mimicking the control input trajectory while the constraints on states and control input remain unimpaired by the weighting matrices is introduced. This approach is demonstrated in a simulation case study involving a continuous stirred tank reactor where a multi-component chemical reaction takes place.
本文介绍了深度神经网络在过程控制中的应用。在我们的方法中,神经网络的训练是基于模型预测控制的,这是受欢迎的,因为它能够通过加权矩阵进行调整,并且尊重系统约束。引入了一种神经网络,通过模拟控制输入轨迹来近似MPC行为,同时状态约束和控制输入约束不受加权矩阵的影响。该方法在一个涉及多组分化学反应发生的连续搅拌槽式反应器的模拟案例研究中得到了证明。
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引用次数: 9
Quantum-chemical studies of rutile nanoparticles toxicity I. Defect-free rod-like model clusters 金红石纳米颗粒毒性的量子化学研究I.无缺陷棒状模型团簇
IF 0.8 Pub Date : 2019-05-14 DOI: 10.2478/acs-2019-0023
M. Breza, P. Simon
Abstract Using the semiempirical PM6 method, structures of a rod-like [Ti40O124H81]7– model cluster and of [Ti40O124H81Cu]5– with Cu2+ coordinated at various sites were optimized in order to assess the toxicity of rutile nanoparticles. If the relative toxicity of individual Ti centers in rod-like rutile nanoparticles can be evaluated by the electron density transfer to a Cu2+ probe, its maximal values can be ascribed to the pentacoordinated corner and hexacoordinated edge Ti centers with three Ti—OH bonds. However, these centers exhibit the least negative interaction energies which can be compensated by the significantly better accessibility of the corner Ti center compared with that of the remaining ones. Ti centers with the most negative interaction energy parameters exhibit the lowest extent of electron density transfer to a Cu2+ probe. Rutile nanoparticles destruction starts at pentacoordinated Ti face centers.
摘要采用半经验PM6方法,优化了棒状[Ti40O124H81]7 -模型簇和Cu2+在不同位点配位的[Ti40O124H81Cu]5 -的结构,以评估金红石纳米颗粒的毒性。如果可以通过Cu2+探针的电子密度转移来评价棒状金红石纳米颗粒中单个Ti中心的相对毒性,则其最大值可归因于具有三个Ti - oh键的五配位角和六配位边Ti中心。然而,这些中心表现出最小的负相互作用能,这可以通过拐角Ti中心比其他中心更好的可达性来补偿。负相互作用能参数最大的Ti中心向Cu2+探针的电子密度转移程度最低。金红石纳米颗粒的破坏始于五配位的钛面中心。
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引用次数: 10
期刊
Acta Chimica Slovaca
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