Chemia Naissensis最新文献_第4页

Revisiting the Arrhenius Equation in Chemical Kinetics to Analyze Kinetics Data for Photochromic Naphthoxazine-spiro-indolines 化学动力学中的Arrhenius方程对光致变色萘恶嗪-螺-吲哚类化合物动力学数据的分析

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn2.1.048h

J. Hobley

{"title":"Revisiting the Arrhenius Equation in Chemical Kinetics to Analyze Kinetics Data for Photochromic Naphthoxazine-spiro-indolines","authors":"J. Hobley","doi":"10.46793/chemn2.1.048h","DOIUrl":"https://doi.org/10.46793/chemn2.1.048h","url":null,"abstract":"In undergraduate courses, kinetics and thermodynamics are often taught as separate modules. It is because equilibrium data from thermodynamics do not enlighten us about the rate of attainment of equilibrium, which is kinetics. It is true that even if a chemical reaction is thermodynamically favorable, it may never happen due to kinetic considerations. However, this separation of kinetics and thermodynamics is unfortunate in some respects. In this work, the link between chemical kinetics and thermodynamics is explored based on them both being defined by a single potential energy diagram. A common misconception caused by undergraduate courses on chemical kinetics is a claim that the Arrhenius equation is deficient because it does not offer a precise meaning for the pre-exponential term A. Undergraduate courses often go on to proffer more sophisticated theories in the form of collision theory CT and transition state theory TST resulting in the Eyring equation. These latter two theories are required in order to formally show that the pre-exponential term contains information on the entropy requirements of the reaction. In this work, it will be shown that by considering the link between thermodynamics and kinetics it can easily be shown that A was already implicitly linked to the product of the entropy of activation of the reaction and the natural frequency of the reaction. This work makes use of previously published and unpublished results on photochromic naphthoxazine-spiro-indolines to compare different theories.","PeriodicalId":351621,"journal":{"name":"Chemia Naissensis","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133922480","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

In vitro antimicrobial activity of „Carum carvi“ L. seed essential oil against pink potato spoilage flora Carum carvi L.种子精油对粉红马铃薯腐败菌群的体外抑菌活性研究

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn3.1.092s

A. Snoussi, H. B. H. Koubaier, Saoussen Bouacida, Ismahen Essaidi, F. Kachouri, N. Bouzouita

{"title":"In vitro antimicrobial activity of „Carum carvi“ L. seed essential oil against pink potato spoilage flora","authors":"A. Snoussi, H. B. H. Koubaier, Saoussen Bouacida, Ismahen Essaidi, F. Kachouri, N. Bouzouita","doi":"10.46793/chemn3.1.092s","DOIUrl":"https://doi.org/10.46793/chemn3.1.092s","url":null,"abstract":"The objective of this research is to assess the ability of using Carum carvi L. seeds essential oil as a biological substance for controlling spoilage germs growth in potatoes during storage. The chemical composition of caraway seeds essential oil, analyzed by GC-MS and by gas chromatography with flame ionization detector (GC-FID), led to the identification of twelve compounds, where carvone was the main one with a percentage of 75.64 % of the total oil. The comparison of the microbial profiles of different potatoes samples showed the presence of the genus Citrobacter and three distinct fungi genera: Aspergillus, Phytophthora and Fusarium only for contaminated potato tubers with internal pink pigmentation. Thus, the antimicrobial activity of caraway seeds essential oil was studied against these strains. The antimicrobial activity of the oil against the isolated strains was evaluated through the agar diffusion method using different volumes (10, 20, 50 and 100 µl). All tested strains were inhibited by caraway seeds essential oil in a dose-dependent manner. The obtained results suggest the use of Carum carvi L. as a promising natural substance for the preservation of potatoes by contact vapor method.","PeriodicalId":351621,"journal":{"name":"Chemia Naissensis","volume":"2009 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130950900","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

Analyses of structure and thermal properties of synthesized crosslinked poly(1-vinyl-2-pyrrolidone-co-vinyl acetate) hydrogels 合成交联聚(1-乙烯基-2-吡咯烷酮-醋酸乙烯酯)水凝胶的结构和热性能分析

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn4.2.29si

S. Ilić-Stojanović, Zorica B. Eraković, Vukašin Ugrinović, S. Petrović

{"title":"Analyses of structure and thermal properties of synthesized crosslinked poly(1-vinyl-2-pyrrolidone-co-vinyl acetate) hydrogels","authors":"S. Ilić-Stojanović, Zorica B. Eraković, Vukašin Ugrinović, S. Petrović","doi":"10.46793/chemn4.2.29si","DOIUrl":"https://doi.org/10.46793/chemn4.2.29si","url":null,"abstract":"This paper describes the process for the synthesis of chemically crosslinked copolymer hydrogels based on monomer 1-vinyl-2-pyrrolidone and comonomer vinyl acetate, using the varied content of ethylene glycol dimethacrylate as a crosslinker, by the free radical polymerization method with thermal initiation. The content of unreacted reactants after poly(1-vinyl-2-pyrrolidone-co-vinyl-acetate), p(VP-VA), hydrogels synthesis was examined using high-pressure liquid chromatography (HPLC) method. Structure characterization of the obtained p(VP-VA) hydrogels was performed using the Fourier transform infrared spectroscopy (FTIR). In this study, the influences of crosslinker content and temperature on the swelling behaviour of p(VP-VA) were studied. Quantities of unreacted comonomers and crosslinker, calculated in relation to the initial amount present in the reaction mixture, confirmed their successful conversion into p(VP-VA) hydrogels. These unreacted values of 1-vinyl-2-pyrrolidone (in range of 0.605-1.609%), vinyl acetate (in range of 2.486-4.798%), and ethylene glycol dimethacrylate (in range of 0.889-3.240%) were within acceptable limits, and they were removed from the final products. FTIR spectra were verified that the copolymerization process was performed, and chemically crosslinking of polymer chains occurred by breaking double bonds from the reactants. Obtained crosslinked copolymers could be classified in the class of negative-thermosensitive hydrogels because they can swell and pass through a phase transition when heated from the swollen state at 25ºC to contracted state at 80ºC.","PeriodicalId":351621,"journal":{"name":"Chemia Naissensis","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127031510","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

Midgut remodeling during the metamorphosis of Chironomus riparius, Meigen (1804) Meigen河鼠(Chironomus riparius, 1804)变态过程中的中肠重塑

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn5.2.22s

Jelena Stojanović, Dimitrija Savić Zdravković, Andrea Žabar Popović, A. Milovanović, Đurađ Milošević

{"title":"Midgut remodeling during the metamorphosis of Chironomus riparius, Meigen (1804)","authors":"Jelena Stojanović, Dimitrija Savić Zdravković, Andrea Žabar Popović, A. Milovanović, Đurađ Milošević","doi":"10.46793/chemn5.2.22s","DOIUrl":"https://doi.org/10.46793/chemn5.2.22s","url":null,"abstract":"The holometabolous insects go through a complete metamorphosis that includes four life stages: egg, larva, pupa, and imago (adult). Chironomus riparius is a suggested model organism by the Organization for Economic Cooperation and Development (OECD) that is used in acute and chronic tests of chemicals. Tissue morphology of healthy non-biting midge larval stage was already described but the faith of the midgut digestive cells and tissue organization during the metamorphosis is unknown. We here described histological alterations of the midgut during ecdysis to distinguish them from the ones caused by toxins’ negative effects. The present study showed differences in tissue architecture of the midgut in the larval, prepupal, and pupal stages of development of C. riparius. During ecdysis, larval digestive cells detached from the midgut epithelium and moved to the lumen. In the pupa, the larval midgut layer was replaced with an adult midgut that had considerably reduced width. These changes in the midgut tissue morphology and organization probably follow changes in the environment and feeding behavior of C. riparius at different stages of development.","PeriodicalId":351621,"journal":{"name":"Chemia Naissensis","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115927059","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

Addition effect of Phoenix canariensis date and different food by-products on the physicochemical and sensory properties of jelly candy 加那利枣和不同食品副产物对果冻糖理化和感官特性的添加影响

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn5.1.64t

Mohamed Turki, A. Snoussi, N. Bouzouita, G. Zeppa

{"title":"Addition effect of Phoenix canariensis date and different food by-products on the physicochemical and sensory properties of jelly candy","authors":"Mohamed Turki, A. Snoussi, N. Bouzouita, G. Zeppa","doi":"10.46793/chemn5.1.64t","DOIUrl":"https://doi.org/10.46793/chemn5.1.64t","url":null,"abstract":"Jelly candy is an appreciated food for consumers, especially children. Its fortification with functional ingredients could show an interesting effect on human health. This study aimed to define the structural and chemical characteristics, especially that of polyphenolic amounts, of apple candies prepared with different percentages (2, 4, and 6%) of grape by-products (Moscato, Chardonnay, Barbera, and Pinot noir), cocoa bean shell (CBS), coffee silverskin and canary date powder, and to evaluate the consumer overall acceptance of these products. The fortification was achieved by replacing different percentages of apple puree with by-product powders. The jelly candies with the canary date and Pinot noir by-product showed the highest quantities of polyphenolic compounds (6.18 and 4.54mg GAE/g DW, respectively) and the greatest antioxidant capacity (24.04 and 26.54µmol TE/g DW, respectively) while the coffee silverskin candy had the lowest values. In general, the use of canary dates and by-product powders in candy production increased hardness, polyphenol and fiber contents, and antioxidant capacity. Sensory analysis showed that the candies obtained with coffee silverskin powder had the least overall liking at 6% substitution. However, no significant differences were recorded between the control and candies at 2 and 4% substitution for all studied functional ingredients","PeriodicalId":351621,"journal":{"name":"Chemia Naissensis","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129840912","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

Antioxidant activity of „Micromeria croatica“ (Pers.) Schott grown in plant tissue culture „in vitro“ versus ones from the natural habitats “croatica Micromeria”的抗氧化活性研究在“离体”植物组织培养中生长的Schott与来自自然栖息地的Schott相比

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn3.1.121t

Svetlana Tošić, D. Stojičić, B. Zlatković, V. Mitić, M. Ilic, M. Marković, V. Stankov-Jovanović

引用次数: 0

Analytical application of poly(vinyl chloride-co-vinyl acetate) electrode modified with silver for chloride ions determination in real systems 银修饰聚氯乙烯-共醋酸乙烯电极在实际体系中氯离子测定中的应用

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn3.1.135s

D. Sejmanović, M. Budimir, Živana Radosavljević, E. Pecev

{"title":"Analytical application of poly(vinyl chloride-co-vinyl acetate) electrode modified with silver for chloride ions determination in real systems","authors":"D. Sejmanović, M. Budimir, Živana Radosavljević, E. Pecev","doi":"10.46793/chemn3.1.135s","DOIUrl":"https://doi.org/10.46793/chemn3.1.135s","url":null,"abstract":"Application possibility of new simple Ag-selective electrode for the determination of chloride ions, was investigated in this paper. The poly(vinyl chloride-co-vinyl acetate) electrode modified with silver (PVCAc/Ag) was prepared by simple immersion a glassy carbon rod coated with poly(vinyl chloride-co- vinyl acetate) polymer, which contained plasticizer and lipophilic additive, but without ionophore, into the silver nitrate solution. This simplicity of construction and extensive pH range through remarkable acidic media (pH 0.7 to 7.0), are the advantages of this modified electrode over many of reported silver selective electrodes based on a polymer matrix containing different ionophores. The response of the electrode was linear with a Nernstian slope of 60.25 mV/decade in the concentration range from 1.0×10-1 to 1.0×10-5 mol/dm3 Ag+ and with a detection limit of 4.25×10-6 mol/dm3. Proposed PVCAc/Ag electrode was applied to the determination of chloride ions in the samples spring waters. The results of chloride ion determination in samples spring waters obtained by proposing electrode and comparative Ag/AgCl electrode were in satisfactory agreement.","PeriodicalId":351621,"journal":{"name":"Chemia Naissensis","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131760119","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

Chair of Organic Chemistry and Biochemistry 有机化学和生物化学主席

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn1.1.034s

G. Stojanović, S. Jovanovic, Marija Gencic

引用次数: 0

Multi-element analysis of methanol apple peel extracts by inductively coupled plasma-optical emission spectrometry 电感耦合等离子体发射光谱法分析甲醇苹果皮提取物

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn3.2.067m

S. Mitić, B. Stojanović, M. Mitić, A. Pavlović, B. Arsić, V. S. Stankov Jovanović

引用次数: 0

Gas-chromatographic analysis of volatile compounds in different types of commercial alcoholic beverages 不同类型商业酒精饮料中挥发性化合物的气相色谱分析

Chemia Naissensis Pub Date : 1900-01-01 DOI: 10.46793/chemn4.2.15s

Jelena Stamenković, G. Stojanović

引用次数: 0