Acta Chimica Slovaca最新文献_第5页

Spectro-chemometric determination of panthenol enantiomeric excess in pharmaceutical products 药品中过量泛醇对映体的光谱化学测定

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Acta Chimica Slovaca Pub Date : 2020-10-01 DOI: 10.2478/acs-2020-0020

R. Poláček, A. Kleinová, P. Májek

{"title":"Spectro-chemometric determination of panthenol enantiomeric excess in pharmaceutical products","authors":"R. Poláček, A. Kleinová, P. Májek","doi":"10.2478/acs-2020-0020","DOIUrl":"https://doi.org/10.2478/acs-2020-0020","url":null,"abstract":"Abstract Antibiotic, soothing and healing properties of panthenol are exploited in various pharmaceutical and cosmetic products. Only D-panthenol is biologically active while its L-form might counteract the biological effectiveness of the D-enantiomer. Hydrating and moisturizing effects are exhibited by both enantiomers. Therefore, it is necessary to develop a rapid and cheap method for the determination of panthenol enantiomeric excess in pharmaceutical preparations. In this study, b-cyclodextrin was used as a chiral selector for the recognition of panthenol enantiomers. Inclusion complexes formed by b-cyclodextrin and the analyte showed small differences in NIR and UV/VIS spectra compared by chemometric assessment. Based on the figure of merit and model characteristics, PLS calibration model in the selected range of NIR spectra is preferred. UV/VIS spectrometry has the disadvantage of complicated sample preparation compared to NIR spectrometry. Results reached by both proposed methods were in good agreement. Statistical investigation of the results (by Student t-test and Fisher F-test) confirmed that the proposed methods are comparable and applicable to chiral analysis of panthenol pharmaceutical preparations.","PeriodicalId":7088,"journal":{"name":"Acta Chimica Slovaca","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46006789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Degradation of low-rank coal excavated from coal-mine Záhorie by filamentous fungi 丝状真菌对Záhorie煤矿低阶煤的降解

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Acta Chimica Slovaca Pub Date : 2020-10-01 DOI: 10.2478/acs-2020-0019

Eva Smoleňová, R. Pokorný, M. Kaliňák, T. Liptaj, M. Šimkovič, L. Varec̆ka

引用次数: 1

Dimethyl sulfoxide as a strongly coordinating solvent: 3′,4′-dihydroxyflavone-Cu(II)-DMSO system case study 二甲基亚砜作为强配位溶剂:3 '，4 ' -二羟黄酮- cu (II)-DMSO体系的案例研究

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Acta Chimica Slovaca Pub Date : 2020-10-01 DOI: 10.2478/acs-2020-0022

Miriama Šimunková, Michal Malček

引用次数: 3

Absorption removal of hydrogen sulfide from recirculated biogas 从循环沼气中吸收去除硫化氢

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Acta Chimica Slovaca Pub Date : 2020-04-01 DOI: 10.2478/acs-2020-0003

Nikolas Gróf, J. Barbušová, Kristína Hencelová, M. Hutňan

{"title":"Absorption removal of hydrogen sulfide from recirculated biogas","authors":"Nikolas Gróf, J. Barbušová, Kristína Hencelová, M. Hutňan","doi":"10.2478/acs-2020-0003","DOIUrl":"https://doi.org/10.2478/acs-2020-0003","url":null,"abstract":"Abstract This study is focused on the effect of biogas recirculation with hydrogen sulfide removal on anaerobic treatment of sulfur-enriched synthetic wastewater in a UASB reactor. The presence of hydrogen sulfide in biogas causes problems in its further energy recovery while sulfides inhibit the anaerobic process. The reactor was gradually loaded with sulfates and their effect on the reactor operation was monitored. At the same time, external absorption of hydrogen sulfide from biogas with absorbent regeneration was operated. The results show that low concentrations of added sulfates support biogas production. At the sulfate concentration of 125 mg l−1, biogas production increased by approximately 2 l d−1. However, further increasing of the amount of sulfates in the substrate led to the opposite effect. At twice the amount of sulfates, the biogas production decrease by 1 l d−1 and its adverse effects on the removal of N-NH4, NC and P-PO4 were observed. Biogas recirculation through the absorption column ensured a decrease in the hydrogen sulfide concentration from 19 960 ppm to 4 030 ppm and an increase in the methane content from 59.2 % to 83 % and also a decrease in the sulfides concentration in the reactor. From the measured data it can be concluded that this method reduces sulfides inhibition.","PeriodicalId":7088,"journal":{"name":"Acta Chimica Slovaca","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45343649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Determination of biological markers of organic substances in sediment and soil samples by gas chromatography 气相色谱法测定沉积物和土壤样品中有机物的生物标志物

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Acta Chimica Slovaca Pub Date : 2020-04-01 DOI: 10.2478/acs-2020-0006

Nemanja Koljančić, O. Vyviurska, Milica Balaban, I. Špánik

{"title":"Determination of biological markers of organic substances in sediment and soil samples by gas chromatography","authors":"Nemanja Koljančić, O. Vyviurska, Milica Balaban, I. Špánik","doi":"10.2478/acs-2020-0006","DOIUrl":"https://doi.org/10.2478/acs-2020-0006","url":null,"abstract":"Abstract Once they reach the environment, petroleum hydrocarbons undergo various chemical, physico-chemical and biochemical transformation processes. Organic compounds which are not or are very poorly subject to these processes are thermodynamically the most stable isomers and they are called biological markers (biomarkers). This paper presents the results of the determination of organic substances in twelve samples taken in the area of the city of Banja Luka (Bosnia and Herzegovina). Two soil samples were taken in the Banja Luka city heating plant area and ten river sediment and soil samples were taken in the upper and lower basin of the Vrbas river in the Banja Luka city area. The aim of this study was to determine the biomarkers of oil-type pollutants in contaminated samples as well as the type of organic substances in samples taken near the contaminated area. Assisted solvent extraction was used to isolate the total petroleum hydrocarbons (TPH) from all twelve samples. Fractionation of the extracts into saturated and aromatic hydrocarbon fractions was performed by column chromatography. The fractions were analyzed by gas chromatography-mass spectrometry (GC-MS). On basis of the obtained chromatograms, biomarkers of petroleum pollutants and specific correlation parameters of organic substances in the samples were determined. The dominance of n-alkanes with odd C atoms as well as the presence of an unresolved complex mixture (UCM) on chromatograms of saturated and aromatic hydrocarbons showed the presence of anthropogenic organic substances of petroleum origin in the analyzed samples. Based on the obtained chromatograms, it can be concluded that microbial degradation of hydrocarbons in all samples occurred.","PeriodicalId":7088,"journal":{"name":"Acta Chimica Slovaca","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47282805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Antibiotic resistant bacteria in surface waters in Slovakia 斯洛伐克地表水中的抗生素耐药性细菌

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Acta Chimica Slovaca Pub Date : 2020-04-01 DOI: 10.2478/acs-2020-0010

Andrea Štefunková, Klára Cverenkárová, Monika Krahulcová, T. Mackuľak, L. Bírošová

{"title":"Antibiotic resistant bacteria in surface waters in Slovakia","authors":"Andrea Štefunková, Klára Cverenkárová, Monika Krahulcová, T. Mackuľak, L. Bírošová","doi":"10.2478/acs-2020-0010","DOIUrl":"https://doi.org/10.2478/acs-2020-0010","url":null,"abstract":"Abstract This work deals with the occurrence of selected antibiotic resistant bacteria in Slovak surface waters. Total and antibiotic resistant coliform bacteria, enterococci and coagulase positive staphylococci were determined in 34 samples of surface water from rivers and still waters (dams, natural lakes, thermal bath) some of them used for recreational swimming. Sampling was performed during summer season 2017 (July and August). The number of total coliforms ranged from 1.74 log CFU/10 mL to 3.69 log CFU/10 mL. Coliform bacteria were registered in each tested sample. The highest number was observed in the sample from river Hron. Majority of samples contained ampicillin and tetracycline resistant bacteria. Enterococci were determined in 70 % of samples ranging from 0.78 log CFU/10 mL to 3.81 log CFU/10 mL. The highest number of enterococci was observed in river Váh. Ampicillin and vancomycin resistance prevailed over ciprofloxacin and gentamicin resistance. Coagulase positive staphylococci were present in 91 % of samples in the range of 0.70—3.03 log CFU/10 mL. Antibiotic resistant coagulase positive staphylococci were observed only in 32 % of samples, predominantly from rivers. In these samples, chloramphenicol resistance predominated. In three samples of water used for recreational purposes, the limit value for enterococci and E. coli according to Slovak legislation (Decree no. 308/2012 Coll.) for the quality of water in natural swimming pools during bathing season was exceeded.","PeriodicalId":7088,"journal":{"name":"Acta Chimica Slovaca","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41282352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Sample matrix influence on microdrop hold-up in single drop microextraction 样品基质对单滴微萃取中微滴率的影响

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Acta Chimica Slovaca Pub Date : 2020-04-01 DOI: 10.2478/acs-2020-0004

N. Kubasová, S. Zichová, Adriána Brisudová, S. Hrouzková

{"title":"Sample matrix influence on microdrop hold-up in single drop microextraction","authors":"N. Kubasová, S. Zichová, Adriána Brisudová, S. Hrouzková","doi":"10.2478/acs-2020-0004","DOIUrl":"https://doi.org/10.2478/acs-2020-0004","url":null,"abstract":"Abstract Single drop microextraction has become a widespread liquid/liquid microextraction technique owing to its simplicity, high preconcentration factor and low consumption of organic solvents in the extraction due to direct introduction of the very low volume of extract into the analytical system. Crucial features ensuring excellent repeatability of single drop microextraction include: solvent volume, solvent type, sample agitation, salts addition, and pH. The influence of sample quality on the microdrop volume and agitation type was studied. Effect of the sample matrix, such as water, acid content samples (orange juice), sample containing alcohol (plum brandy) and protein content sample (milk), on the microdrop hold-up was also investigated. For water analysis, several organic solvents such as chloroform, dichloromethane, tetrachloromethane, tetrachloroethane and chlorobenzene were tested; last three mentioned were suitable for SDME experiments. For milk samples analysis, chlorobenzene microdrop was found to be optimal; advantage of salt addition has been reported. For orange samples, 1:10 dilution was suggested with stable microdrop volumes (toluene) of up to 6 µL for lower stirring rates (100 rpm and 250 rpm). For alcohol-content samples, the change of alcohol percentage of real-life samples had to be considered. A strong influence of the matrix quality on the microdrop stability has been proven.","PeriodicalId":7088,"journal":{"name":"Acta Chimica Slovaca","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42194001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Low-temperature plasma applications in chemical fungicide treatment reduction 低温等离子体在化学杀菌剂处理还原中的应用

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Acta Chimica Slovaca Pub Date : 2020-04-01 DOI: 10.2478/acs-2020-0005

Lucia Hoppanová, V. Medvecká, Juliana Dylíková, D. Hudecová, B. Kaliňáková, S. Kryštofová, A. Zahoranová

{"title":"Low-temperature plasma applications in chemical fungicide treatment reduction","authors":"Lucia Hoppanová, V. Medvecká, Juliana Dylíková, D. Hudecová, B. Kaliňáková, S. Kryštofová, A. Zahoranová","doi":"10.2478/acs-2020-0005","DOIUrl":"https://doi.org/10.2478/acs-2020-0005","url":null,"abstract":"Abstract In order to reduce the environmental burden of chemicals, various new alternatives to seed protection are being sought. Our aim was to find an environmentally acceptable solution leading to the inactivation of seed-borne phytopathogenic fungi Fusarium culmorum on the surface of wheat and barley seeds with a positive effect on their germination. As a low-temperature plasma (LTP) source, a Diffuse Coplanar Surface Barrier Discharge (DCSBD) was used. Plasma generated by DCSBD is non-equilibrium, cold, diffuse, macroscopically homogeneous even in ambient air at atmospheric pressure. Experimental results showed that LTP treatment in the range of 120—300 s significantly inhibits the growth of F. culmorum on the surface of the seeds. The efficiency of LTP treatment was compared with traditional seed protection processes using chemical fungicide and also with combined seed pretreatment by plasma and subsequent application of chemical fungicide. No growth of F. culmorum was observed after the combination of Vitavax 2000 fungicide application in the dose of 10 % and 60 s of LTP treatment even on the 5th day of incubation. Better wettability of seeds with the chemical fungicide was related to the change on seed surface, which becomes hydrophilic after 10 s of LTP application. Short LTP exposure times did not affect germination and improved the growth parameter of cereal seeds. By combining physical (LTP) and chemical (Vitavax 2000) treatments of cereal seeds, it is possible to effectively reduce the required amount of chemical fungicide and to stimulate germination and early growth seed parameters.","PeriodicalId":7088,"journal":{"name":"Acta Chimica Slovaca","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45223703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Control of heat exchangers in series using neural network predictive controllers 基于神经网络预测控制器的换热器串联控制

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Acta Chimica Slovaca Pub Date : 2020-04-01 DOI: 10.2478/acs-2020-0007

A. Vasickaninova, M. Bakosová, A. Mészáros

{"title":"Control of heat exchangers in series using neural network predictive controllers","authors":"A. Vasickaninova, M. Bakosová, A. Mészáros","doi":"10.2478/acs-2020-0007","DOIUrl":"https://doi.org/10.2478/acs-2020-0007","url":null,"abstract":"Abstract The paper reveals three applications of neural network predictive control (NNPC) to a system of four heat exchangers (HEs) in series with counterflow configuration to save energy expressed by cooling water in the system of HEs cooling the distillation product. Neural networks (NNs) are used at first in conventional NNPC and subsequently, neural network predictive controllers (NNPCLs) are employed as a master controller in a cascade control, and as a feedback controller in the control system with disturbance measurement. Neural-network-predictive-control-based (NNPC-based) feedback control systems are compared with PI controller based feedback control loop. Series of simulation experiments were done and the results showed that using NNPC-based cascade control reduced cooling water consumption. This control system also significantly reduced the settling time and overshoots in the control responses and provided the best assessed integral quality criteria compared to other control systems. NNPC-based cascade control can also be interesting for industrial use. Generally, simulation results proved that NNPC-based control systems are promising means for the improvement of HEs control and achievement of energy saving.","PeriodicalId":7088,"journal":{"name":"Acta Chimica Slovaca","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47314952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of trans-polyoctylene rubber content on styrene-butadiene rubber properties 反式聚辛基橡胶含量对丁苯橡胶性能的影响

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Acta Chimica Slovaca Pub Date : 2020-04-01 DOI: 10.2478/acs-2020-0001

Patrik Macúrik, R. Anyszka, I. Hudeč, Terézia Malčeková, J. Kruželák

引用次数: 1