Croatica Chemica Acta最新文献_第4页

Advances in Desmuramyl Peptide Research 去壁酰肽研究进展

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2019-07-29 DOI: 10.5562/cca3556

R. Ribić, Marija Paurević, S. Tomić

引用次数: 3

Estimation of Random Accuracy and its Use in Validation of Predictive Quality of Classification Models within Predictive Challenges 随机精度估计及其在预测挑战下分类模型预测质量验证中的应用

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2019-07-29 DOI: 10.5562/cca3551

B. Lučić, Jadranko Batista, V. Bojović, M. Lovrić, Ana Sovic Krzic, D. Bešlo, Damir Nadramija, D. Vikić-Topić

{"title":"Estimation of Random Accuracy and its Use in Validation of Predictive Quality of Classification Models within Predictive Challenges","authors":"B. Lučić, Jadranko Batista, V. Bojović, M. Lovrić, Ana Sovic Krzic, D. Bešlo, Damir Nadramija, D. Vikić-Topić","doi":"10.5562/cca3551","DOIUrl":"https://doi.org/10.5562/cca3551","url":null,"abstract":"Shortcomings of the correlation coefficient (Pearson's) as a measure for estimating and calculating the accuracy of predictive model properties are analysed. Here we discuss two such cases that can often occur in the application of the model in predicting properties of a new external set of compounds. The first problem in using the correlation coefficient is its insensitivity to the systemic error that must be expected in predicting properties of a novel external set of compounds, which is not a random sample selected from the training set. The second problem is that an external set can be arbitrarily large or small and have an arbitrary and uneven distribution of the measured value of the target variable, whose values are not known in advance. In these conditions, the correlation coefficient can be an overoptimistic measure of agreement of predicted values with the corresponding experimental values and can lead to a highly optimistic conclusion about the predictive ability of the model. Due to these shortcomings of the correlation coefficient, the use of standard error (root-mean-square-error) of prediction is suggested as a better quality measure of predictive capabilities of a model. In the case of classification models, the use of the difference between the real accuracy and the most probable random accuracy of the model shows very good characteristics in ranking different models according to predictive quality, having at the same time an obvious interpretation.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/cca3551","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42254070","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: 25

The Phenanthridine-modified Tyrosine Dipeptide 菲咯啶修饰的酪氨酸二肽

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2019-07-29 DOI: 10.5562/CCA3542

Antonija Erben, J. Matić, N. Basarić, I. Piantanida

{"title":"The Phenanthridine-modified Tyrosine Dipeptide","authors":"Antonija Erben, J. Matić, N. Basarić, I. Piantanida","doi":"10.5562/CCA3542","DOIUrl":"https://doi.org/10.5562/CCA3542","url":null,"abstract":"Dipeptide 4 containing two unnatural amino acids, a modified tyrosine and a phenanthridine derivative, was synthesized. Binding of the dipeptide to a series of polynucleotides including ct-DNA, poly A - poly U, poly (dAdT)2, poly dG - poly dC and poly (dGdC)2 was investigated by thermal denaturation experiments, fluorescence spectroscopy and circular dichroism. Thermal denaturation experiments indicated that dipeptide 4 at pH 5.0, when phenanthridine is protonated, stabilizes ds-DNA, whereas it destabilizes ds-RNA. At pH 7.0, when the phenanthridine is not protonated, effects of 4 to the polynucleotide melting temperatures are negligible. At pH 5.0, dipeptide 4 stabilized DNA double helices, and the changes in the CD spectra suggest different modes of binding to ds-DNA, most likely the intercalation to poly dG- poly dC and non-specific binding in grooves of other DNA polynucleotides. At variance to ds-DNA, addition of 4 destabilized ds-RNA against thermal denaturation and CD results suggest that addition of 4 probably induced dissociation of ds-RNA into ss-RNA strands due to preferred binding to ss-RNA. Thus, 4 is among very rare small molecules that stabilize ds-DNA but destabilize ds-RNA. However, fluorescence titrations with all polynucleotides at both pH values gave similar binding affinity (log Ka ≈ 5), indicating nonselective binding. Preliminary photochemical experiments suggest that dipeptide 4 reacts in the photochemical reaction, which affects polynucleotides chirality, presumably via quinone methide intermediates that alkylate DNA.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/CCA3542","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42312677","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

Synthesis, Spectral Analysis, Molecular Docking and Biological Evaluation of Cyclohepta[b]indole Derivatives 环庚[b]吲哚衍生物的合成、光谱分析、分子对接及生物学评价

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2019-07-29 DOI: 10.5562/cca3375

A. Amuthavalli, B. Prakash, D. Edison, R. Velmurugan

引用次数: 2

Marking a Century of the Department of Chemistry and Biochemistry at School of Medicine in Zagreb 萨格勒布医学院化学与生物化学系百年校庆

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2019-07-29 DOI: 10.5562/cca3554

Kristina Mlinac-Jerković, V. Damjanović, S. Kalanj-Bognar, J. Lovrić

{"title":"Marking a Century of the Department of Chemistry and Biochemistry at School of Medicine in Zagreb","authors":"Kristina Mlinac-Jerković, V. Damjanović, S. Kalanj-Bognar, J. Lovrić","doi":"10.5562/cca3554","DOIUrl":"https://doi.org/10.5562/cca3554","url":null,"abstract":"In 2018 the Department of Chemistry and Biochemistry at Zagreb School of Medicine celebrated 100 years since it was established by professor Fran Bubanović. This essay is focused on his successors, outstanding teachers and scientists, professors Tomislav Pinter and Mihovil Proštenik, members of Yugoslavian (today Croatian) Academy of Sciences and Arts. Tomislav Pinter was a prominent physical chemist who had an original approach and gave novel interpretation of van der Waals and Wohl’s equations. He also served as the president of Croatian Chemical Society. Neurobiochemist Mihovil Proštenik started as an organic chemist at “Prelog’s Zagreb School of Organic Chemistry”. He collaborated with two Croatian Nobel prize winners in chemistry: his PhD thesis supervisor Vladimir Prelog and Lavoslav Ružička. He was the founder of “Zagreb School of Lipidology”, discovered a new sphingoid base C20-sphingosine, and had a major role in the establishment of Ruđer Bošković Institute. Herein we honor their contributions to Croatian science and beyond, and share so far unpublished valuable material from the Department archive.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/cca3554","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44806409","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

Evaluation of the Radical-Scavenging Properties of Various Flavonols in Ethanol Environment: an ab initio Study 不同黄酮醇在乙醇环境中清除自由基性能的从头算研究

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2019-07-29 DOI: 10.5562/cca3449

Raluca Pop

{"title":"Evaluation of the Radical-Scavenging Properties of Various Flavonols in Ethanol Environment: an ab initio Study","authors":"Raluca Pop","doi":"10.5562/cca3449","DOIUrl":"https://doi.org/10.5562/cca3449","url":null,"abstract":"The antioxidant properties of six flavonols -fisetin, galangin, gossipetin, kaempferol, morin and myricetin- have been investigated at HF/6-311G+(d,p) level of theory, using ethanol as solvent. Three known antioxidant mechanisms, namely HAT (hydrogen atom transfer), SET-PT (single electron transfer followed by proton transfer) and SPLET (sequential proton loss electron transfer) have been employed in order to evaluate the radical scavenging abilities of the investigated compounds. Thermodynamic parameters like bond dissociation energy (BDE), proton affinity (PA), electron transfer enthalpy (ETE), ionization potential (IP) and proton dissociation enthalpy (PDE) were calculated and the results were associated with the number and the positions of the hydroxyl groups, the geometry of the parent molecule and of the corresponding radicals, as well as with the electron spin distribution. Also, computations of global reactivity descriptors like HOMO-LUMO gap showed that an increased reactivity is related to the presence of the catechol moiety (gossipetin, myricetin, fisetin). The influence of the catecholic OH groups is also outlined by the HOMO energies, highest electron-donor ability being obtained for gossipetin, the flavonol with two catecholic moieties on rings A and B. According to the HAT mechanism, it has been outlined an enhanced antioxidant character of the 3-OH groups, followed by the hydroxyl groups attached to the phenyl ring B. The calculated values of the condensed Fukui functions, computed for a radical attack, are in good agreement with the above-mentioned results.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":" ","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/cca3449","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42732113","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

The Effect of Selected Herb Extracts on Oxidative Stability of Vegetable Oils 草药提取物对植物油氧化稳定性的影响

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2019-07-29 DOI: 10.5562/cca3479

Barbara Soldo, N. Nikolov, Ivana Generalić Mekinić, I. Ljubenkov, Vida Šimat, Danijela Skroza, I. Anđelić

引用次数: 5

Synthesis and Mesomorphic Properties of Novel Bent-shaped Naphthyl Diketones 新型弯曲萘二酮的合成及介晶性质

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2019-07-29 DOI: 10.5562/cca3541

Anđela Buljan, A. Knežević, I. Dokli, A. Lesac

引用次数: 2

Electrofugality of Some Ferrocenylphenylmethyl Cations 某些二茂铁苯基甲基阳离子的电逸性