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Three different techniques to reconstruct 3D view of SEM images by using only free available software 三种不同的技术重建三维视图扫描电镜图像仅使用免费软件
IF 0.6 4区 化学
Chemija Pub Date : 2022-02-07 DOI: 10.6001/chemija.v33i1.4658
Edvardas Brimas, R. Skaudžius, G. Brimas, A. Selskis, R. Ramanauskas, A. Kareiva
{"title":"Three different techniques to reconstruct 3D view of SEM images by using only free available software","authors":"Edvardas Brimas, R. Skaudžius, G. Brimas, A. Selskis, R. Ramanauskas, A. Kareiva","doi":"10.6001/chemija.v33i1.4658","DOIUrl":"https://doi.org/10.6001/chemija.v33i1.4658","url":null,"abstract":"In the present work, three different techniques were used to obtain a 3D view of the SEM images of adipose tissue samples taken from volunteer obese patients by only freely available software. The extrapolation of spatial data demonstrates the most promising results compared to the results of a stereoscopic view or interactive surface plots. The 3D reconstructed view of SEM images by extrapolation of spatial data allows one to obtain the depth of the sample from the SEM images. The reconstructed model also might be printed with a 3D printer, which extends the usage possibilities of this technique.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42166071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Equilibration processes in alkaline Cu | Cu(II), glycine system 碱性Cu|Cu（II），甘氨酸体系中的平衡过程
IF 0.6 4区 化学
Chemija Pub Date : 2022-02-07 DOI: 10.6001/chemija.v33i1.4660
A. Survila, S. Kanapeckaitė, L. Staišiūnas, L. Gudavičiūtė, O. Girčienė
{"title":"Equilibration processes in alkaline Cu | Cu(II), glycine system","authors":"A. Survila, S. Kanapeckaitė, L. Staišiūnas, L. Gudavičiūtė, O. Girčienė","doi":"10.6001/chemija.v33i1.4660","DOIUrl":"https://doi.org/10.6001/chemija.v33i1.4660","url":null,"abstract":"The nature and kinetics of the equilibrium processes at the interface between the copper electrode and the alkaline solution containing glycine complexes of Cu(II) have been studied. The material balance equations that consider the formation of Сu(I) complexes were used to calculate the composition of the equilibrium system. It was found that the amount of Сu(I) compounds increases with increasing the pH and ligand concentration. Using the EQCM method it was found that the electrochemical dissolution of Cu electrode proceeds under open circuit conditions at potentials 60–70 mV higher than their equilibrium values. The generation of Cu+ ions obeys the laws of pseudo-first order processes at a rate constant of ~2 × 10–4 s–1. It is assumed that the final product of the equilibration is a monoligand complex of CuL (L– is a glycinate anion). Besides, there is a thermodynamic probability of the formation of cuprous oxide in the system.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41722928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Design and applications of a neural networks assisted portable liquid surface tensiometer 神经网络辅助便携式液体表面张力计的设计与应用
IF 0.6 4区 化学
Chemija Pub Date : 2021-11-09 DOI: 10.6001/chemija.v32i3-4.4545
Tomas Drevinskas, Jūratė Balevičiūtė, K. Bimbiraitė-Survilienė, Gediminas Dūda, M. Stankevičius, Nicola Tiso, R. Mickienė, Domantas Armonavičius, D. Levisauskas, V. Kaškonienė, O. Ragažinskienė, S. Grigiškis, E. Donati, M. Zacchini, A. Maruška
{"title":"Design and applications of a neural networks assisted portable liquid surface tensiometer","authors":"Tomas Drevinskas, Jūratė Balevičiūtė, K. Bimbiraitė-Survilienė, Gediminas Dūda, M. Stankevičius, Nicola Tiso, R. Mickienė, Domantas Armonavičius, D. Levisauskas, V. Kaškonienė, O. Ragažinskienė, S. Grigiškis, E. Donati, M. Zacchini, A. Maruška","doi":"10.6001/chemija.v32i3-4.4545","DOIUrl":"https://doi.org/10.6001/chemija.v32i3-4.4545","url":null,"abstract":"In this paper, a portable instrument for surface tension measurements, characterization and applications is described. The instrumentation is operated wirelessly, and samples can be measured in situ. The instrument has changeable different size probes; therefore, it is possible to measure samples from 1 ml up to 10 ml. The response of the measured retraction force and the concentrations of measured surfactant is complex. Therefore, two calibration methods were proposed: (i) the conditional calibration using polynomial and logarithmic fitting and (ii) the neural network trained model prediction of the surfactant concentration in samples. Calibrating the instrument, the neural network trained model showed a superior coefficient of determination (0.999), comparing it to the conditional calibration using polynomial (0.992) and logarithmic (0.991) fit equations.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71269430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Cirsium vulgare leaves: isolation and identification of phenolic compounds 大圆叶酚类化合物的分离鉴定
IF 0.6 4区 化学
Chemija Pub Date : 2021-11-09 DOI: 10.6001/chemija.v32i3-4.4547
U. Griškevičienė, M. Marksa, A. Ževžikovienė, Daiva Kazlauskienė, R. Vainorienė, A. Ževžikovas, L. Ivanauskas
{"title":"Cirsium vulgare leaves: isolation and identification of phenolic compounds","authors":"U. Griškevičienė, M. Marksa, A. Ževžikovienė, Daiva Kazlauskienė, R. Vainorienė, A. Ževžikovas, L. Ivanauskas","doi":"10.6001/chemija.v32i3-4.4547","DOIUrl":"https://doi.org/10.6001/chemija.v32i3-4.4547","url":null,"abstract":"There are a few new researches on the pharmaceutical and nutraceutical application of Cirsium vulgare, but they do not reflect the full potential use of this plant. For the best of our knowledge, no study has been conducted so far to determine the impact of extraction methods and conditions on the extraction yields of phenolic compounds from Cirsium vulgare. We aimed to investigate a simple and sensitive HPLC-PDA method to determine phenolic compounds in Cirsium vulgare extracts. Three extraction techniques as maceration (ME), ultrasound-assisted extraction (UAE) and heat-reflux extraction (HRE) were applied and compared for sample preparation to obtain a high recovery of the phenolic compounds. The developed HPLC-PDA method can be used for the preparations of extracts with a high content of bioactive compounds for both pharmaceutical and nutraceutical applications. Moreover, it was validated and used for the qualitative and quantitative evaluation of phenolic compounds. A simple extraction procedure for phenolic compounds from Cirsium vulgare leaves was optimized in this work through the use of the heatreflux extraction method with 50% ethanol and extraction time of 1.5 h.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48460612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Porous poly(urethane urea) microparticles for immobilization of maltogenic α amylase from Bacillus stearothermophilus 多孔聚氨基甲酸乙酯脲微颗粒固定化嗜热脂肪芽孢杆菌产麦芽α淀粉酶
IF 0.6 4区 化学
Chemija Pub Date : 2021-11-09 DOI: 10.6001/chemija.v32i3-4.4550
Antanas Strakšys, Tatjana Kochane, Sandra Maciulyte, S. Budriene
{"title":"Porous poly(urethane urea) microparticles for immobilization of maltogenic α amylase from Bacillus stearothermophilus","authors":"Antanas Strakšys, Tatjana Kochane, Sandra Maciulyte, S. Budriene","doi":"10.6001/chemija.v32i3-4.4550","DOIUrl":"https://doi.org/10.6001/chemija.v32i3-4.4550","url":null,"abstract":"Maltogenic α amylase from Bacillus stearothermophilus (BsMa) was immobilized by covalent attachment and physical adsorption onto porous poly(urethane urea) (PUU) microparticles obtained from poly(vinyl alcohol) (PVA) and 4,4’-methylenebis(cyclohexyl diisocyanate) (H12DI) by onepot synthesis. The influence of PUU synthesis parameters such as PVA and H12DI molar ratio, synthesis time and temperature on porosity, surface area, structure of microparticles and catalytic activity and stability of immobilized BsMa was investigated. The highest efficiency of the immobilization of BsMa onto the PUU carrier was 97% and the highest residual stability of the immobilized enzyme reached 95% after 28 days of storage at 4°C. The optimal activity temperature of immobilized BsMa was at 80°C and it was higher than that of native enzyme. Effects of ionic strength and repetitive batch processing cycles on the activity of immobilized BsMa were also studied. Immobilization of BsMa onto PUU carriers has a great potential for biotechnology and food industries.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43165597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Characterization of natural silicate garnets by means of non-destructive testing methods 用无损检测方法对天然硅酸盐石榴石进行表征
IF 0.6 4区 化学
Chemija Pub Date : 2021-11-09 DOI: 10.6001/chemija.v32i3-4.4549
Irena Balčiūnaitė, I. Ignatjev, D. Kaminskas, G. Niaura, E. Norkus
{"title":"Characterization of natural silicate garnets by means of non-destructive testing methods","authors":"Irena Balčiūnaitė, I. Ignatjev, D. Kaminskas, G. Niaura, E. Norkus","doi":"10.6001/chemija.v32i3-4.4549","DOIUrl":"https://doi.org/10.6001/chemija.v32i3-4.4549","url":null,"abstract":"Two kinds of natural silicate garnets from the known origin countries were investigated: pyralspites – pyrope (Russia), almandine (India), rhodolite (India), spessartine (India), blue colour-change garnet (Sri Lanka), and ugrandites – andradite (Russia), demantoid (Russia), topazolite (Russia), rainbow garnet (Japan), grossular (Kenya-Tanzania), colourless grossular (India), light orange grossular (India), dark green tsavorite (Tanzania), medium green tsavorite (Kenya), light green tsavorite (Kenya), orange hessonite (Sri Lanka), pink hessonite (Sri Lanka), cinnamon hessonite (India) and uvarovite (Russia). The chemical composition of the garnets was performed with a scanning electron microscope. The physical properties such as specific gravity and refractive index were measured for the majority of garnets investigated. The spectroscopic meth­ods – visible light absorption spectrophotometry, Raman spectroscopy and cathodoluminiscence microscopy – were applied for the characterization of the mentioned natural silicate garnets.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46712840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Home-made cider brandy (Calvados): analysis of distillation fractions by gas chromatography-mass spectrometry method 自制苹果白兰地(Calvados):气相色谱-质谱联用分析
IF 0.6 4区 化学
Chemija Pub Date : 2021-11-09 DOI: 10.6001/chemija.v32i3-4.4546
Indrė Vaičikauskytė, Vilius Poškus, V. Nekrošius, V. Vickackaite, A. Kareiva
{"title":"Home-made cider brandy (Calvados): analysis of distillation fractions by gas chromatography-mass spectrometry method","authors":"Indrė Vaičikauskytė, Vilius Poškus, V. Nekrošius, V. Vickackaite, A. Kareiva","doi":"10.6001/chemija.v32i3-4.4546","DOIUrl":"https://doi.org/10.6001/chemija.v32i3-4.4546","url":null,"abstract":"In this study, the distillation fractions of cider brandy produced illegally in Lithuania using gas chromatographic-mass spectrometry method were investigated. The conditions of gas chromatography-mass spectrometry were firstly optimized. A qualitative analysis of three distillation fractions was performed and estimated. The first fraction (initial) of distillation products was collected for 0.5 h, the second one (intermediate) was collected for the next 1.5 h and the third (main) fraction for the next 5 h. A method of the quantitative analysis of different volatile analytes such as acetaldehyde, methanol, ethanol, 1-propanol, isobutanol, 1-butanol, isoamyl alcohol and benzyl alcohol in the distillation products was also developed. The concentration of ethanol decreased significantly in the main fraction in comparison with those of the initial and intermediate fractions. The concentration of 1-propanol, isobutanol, 1-butanol and isoamyl alcohol in the last fraction decreased drastically as well.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45720823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Aqueous dispersions of epoxy oligomers: Stability and rheological properties 环氧低聚物的水分散体:稳定性和流变性能
IF 0.6 4区 化学
Chemija Pub Date : 2021-11-09 DOI: 10.6001/chemija.v32i3-4.4551
D. Busel, V. D. Koshevar, A. Zarkov, V. G. Shkadrecova, A. Kareiva
{"title":"Aqueous dispersions of epoxy oligomers: Stability and rheological properties","authors":"D. Busel, V. D. Koshevar, A. Zarkov, V. G. Shkadrecova, A. Kareiva","doi":"10.6001/chemija.v32i3-4.4551","DOIUrl":"https://doi.org/10.6001/chemija.v32i3-4.4551","url":null,"abstract":"In this study, the stability of the aqueous dispersions of epoxy oligomers was investigated. The following epoxy oligomers with various numbers of epoxy groups were used for the characterization: NPEL 127, NPEL 128, NPEL 134, NPPN 631, EPOXY 520 and DEG-1. A non-ionic surfactant Emulsogen LCN-287 based on alkyl polyethylene glycol ether was used as an emulsifier. The dispersions of epoxy resins were fabricated by changing the content of a non-ionic surfactant (emulsifier) in a range from 2 to 6 wt.%. It was demonstrated that the stability of aqueous emulsions depends not only on the type of resin, but also on the content of the oil phase and the concentration of the emulsifier. The rheological properties of the aqueous dispersions of epoxy oligomers were investigated as well.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41820447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Headspace gas chromatographic determination of β-caryophyllene in Epilobium angustifolium L. extracts 顶空气相色谱法测定枇杷叶提取物中β-石竹烯的含量
IF 0.6 4区 化学
Chemija Pub Date : 2021-11-09 DOI: 10.6001/chemija.v32i3-4.4548
V. Vickackaite, Marija Lukoševičiūtė, Vilius Poškus
{"title":"Headspace gas chromatographic determination of β-caryophyllene in Epilobium angustifolium L. extracts","authors":"V. Vickackaite, Marija Lukoševičiūtė, Vilius Poškus","doi":"10.6001/chemija.v32i3-4.4548","DOIUrl":"https://doi.org/10.6001/chemija.v32i3-4.4548","url":null,"abstract":"Epilobium angustifolium L. is a plant widely used in folk medicine. It is rich in biologically active compounds including phenols, flavonoids, terpenes, aliphatic acids and sterols; however, until now, little attention has been paid to its volatile components. This research demonstrated that Epilobium angustifolium L. is rich in β-caryophyllene that is possibly responsible for its unique therapeutic properties. The leaves of Epilobium angustifolium L. are traditionally used as a tea. On the other hand, β-caryophyllene is soluble in oils, thus an extract of Epilobium angustifolium L. in edible oils should also demonstrate a healing effect. Therefore, quick and reliable methods of β-caryophyllene determination in edible oils and in water solutions are required. In this work, headspace gas chromatography is suggested to determine β-caryophyllene. At the optimized chromatographic conditions for β-caryophyllene solutions in coconut oil the calibration curve was linear up to 10 mg g–1, the detection limit was 60 µg kg–1, for β-caryophyllene solutions in water the calibration curve was linear up to 40 µg l–1, and the detection limit was 6 µg l–1. The methods were applied for the β-caryophyllene determination in the extract of Epilobium angustifolium L. in sunflower oil and in Epilobium angustifolium L. tea.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46358056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Silver-coated monolitic silica column for separation of benzo[a]pyrene from petroleum 从石油中分离苯并[a]芘的银包被单层硅胶柱
IF 0.6 4区 化学
Chemija Pub Date : 2021-05-29 DOI: 10.6001/CHEMIJA.V32I2.4432
Vilius Poškus, V. Vickackaite, Justina Rokaitė
{"title":"Silver-coated monolitic silica column for separation of benzo[a]pyrene from petroleum","authors":"Vilius Poškus, V. Vickackaite, Justina Rokaitė","doi":"10.6001/CHEMIJA.V32I2.4432","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V32I2.4432","url":null,"abstract":"Department of Analytical and Environmental Chemistry, Vilnius University, 24 Naugarduko Street, 03225 Vilnius, Lithuania Monolithic silica solid-phase extraction column has been successfully applied for the rapid fractionation and subsequent gas chromatographic analysis of benzo[a]pyrene from the diesel and oil matrix. Due to π-π electronic interactions between silver nanoparticles on the sorbent surface and aromatic analyte specific retention was achieved. It was demonstrated that only 0.2 g of the sorbent and 6 ml of the organic solvent are enough for such separation.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42846921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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