Central European Journal of Chemistry最新文献_第9页

A procedure for meaningful unsupervised clustering and its application for solvent classification 一种有意义的无监督聚类方法及其在溶剂分类中的应用

Central European Journal of Chemistry Pub Date : 2014-02-21 DOI: 10.2478/s11532-014-0514-6

Yaroslava Pushkarova, Y. Kholin

{"title":"A procedure for meaningful unsupervised clustering and its application for solvent classification","authors":"Yaroslava Pushkarova, Y. Kholin","doi":"10.2478/s11532-014-0514-6","DOIUrl":"https://doi.org/10.2478/s11532-014-0514-6","url":null,"abstract":"AbstractArtificial neural networks have proven to be a powerful tool for solving classification problems. Some difficulties still need to be overcome for their successful application to chemical data. The use of supervised neural networks implies the initial distribution of patterns between the pre-determined classes, while attribution of objects to the classes may be uncertain. Unsupervised neural networks are free from this problem, but do not always reveal the real structure of data. Classification algorithms which do not require a priori information about the distribution of patterns between the pre-determined classes and provide meaningful results are of special interest. This paper presents an approach based on the combination of Kohonen and probabilistic networks which enables the determination of the number of classes and the reliable classification of objects. This is illustrated for a set of 76 solvents based on nine characteristics. The resulting classification is chemically interpretable. The approach proved to be also applicable in a different field, namely in examining the solubility of C60 fullerene. The solvents belonging to the same group demonstrate similar abilities to dissolve C60. This makes it possible to estimate the solubility of fullerenes in solvents for which there are no experimental data\u0000","PeriodicalId":9888,"journal":{"name":"Central European Journal of Chemistry","volume":"35 1","pages":"594-603"},"PeriodicalIF":0.0,"publicationDate":"2014-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75116102","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: 8

Surface plasmon resonance imaging biosensors for aromatase based on a potent inhibitor and a specific antibody: Sensor development and application for biological material 基于有效抑制剂和特异性抗体的芳香化酶表面等离子体共振成像生物传感器:生物材料传感器的开发与应用

Central European Journal of Chemistry Pub Date : 2014-02-21 DOI: 10.2478/s11532-014-0512-8

E. Gorodkiewicz, A. Sankiewicz, P. Laudański

{"title":"Surface plasmon resonance imaging biosensors for aromatase based on a potent inhibitor and a specific antibody: Sensor development and application for biological material","authors":"E. Gorodkiewicz, A. Sankiewicz, P. Laudański","doi":"10.2478/s11532-014-0512-8","DOIUrl":"https://doi.org/10.2478/s11532-014-0512-8","url":null,"abstract":"AbstractAromatase (ARO) is an enzyme with potential diagnostic significance. Aberrant expression of aromatase in tissues is associated with a number of pathological conditions, including tumor of the breast, ovary, testes, liver, adrenal cortex and uterus, as well as endometriosis.Two methods for the highly selective determination of ARO concentration in human tissues by using of two different biosensors co-operating with the surface plasmon resonance imaging technique (SPRI) have been developed. One of the developed biosensors contains immobilised rabbit polyclonal antibody specific for aromatase (Y-ARO), while the other contains immobilized ARO inhibitor-exemestane (E-ARO). Both biosensors specifically bound ARO from analyzed samples. The analytically useful dynamic response range of both biosensors is between 0.3 and 5.0 ng mL−1. The detection limit (3S.D.) of both biosensors is 90 pg mL−1. Standard deviation of both biosensors is 1%. Recoveries of ARO spikes are between 97 and 108% for both biosensors under model conditions and for real samples. Albumin and alkaline phosphatase are tolerated for both biosensors up to 10,000 fold excess.\u0000","PeriodicalId":9888,"journal":{"name":"Central European Journal of Chemistry","volume":"97 1","pages":"557-567"},"PeriodicalIF":0.0,"publicationDate":"2014-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85911970","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: 26

Regio- and stereoselectivity of polar [2+3] cycloaddition reactions between (Z)-C-(3,4,5-trimethoxyphenyl)-N-methylnitrone and selected (E)-2-substituted nitroethenes (Z)- c -(3,4,5-三甲氧基苯基)- n -甲基硝酮与(E)-2-取代亚硝基之间极性[2+3]环加成反应的区域选择性和立体选择性

Central European Journal of Chemistry Pub Date : 2014-02-21 DOI: 10.2478/s11532-014-0518-2

R. Jasiński, Magda Ziółkowska, O. Demchuk, Agata Maziarka

引用次数: 55

Experimental and theoretical studies on the photodegradation of 2-ethylhexyl 4-methoxycinnamate in the presence of reactive oxygen and chlorine species 活性氧和氯存在下2-乙基己基4-甲氧基肉桂酸光降解的实验和理论研究

Central European Journal of Chemistry Pub Date : 2014-02-21 DOI: 10.2478/s11532-014-0522-6

Alicja Gackowska, Maciej Przybyłek, W. Studziński, J. Gaca

引用次数: 32

TOF-SIMS surface analysis of L-Tryptophan self assembled monolayer l -色氨酸自组装单层的TOF-SIMS表面分析

Central European Journal of Chemistry Pub Date : 2014-02-21 DOI: 10.2478/s11532-014-0515-5

M. Petrovic, I. Talian, Lenka Škantárová, A. Oriňak, D. Velic

{"title":"TOF-SIMS surface analysis of L-Tryptophan self assembled monolayer","authors":"M. Petrovic, I. Talian, Lenka Škantárová, A. Oriňak, D. Velic","doi":"10.2478/s11532-014-0515-5","DOIUrl":"https://doi.org/10.2478/s11532-014-0515-5","url":null,"abstract":"AbstractThis paper dealt with the preparation and characterization of self — assembled monolayersSAM-s of 1-hexadecanethiole and mercapto acetic acid on the silver nanostructure and subsequently the immobilization with amino acid L-Tryptophane. In order to achieve it, we used the electrodeposition of silver onto nanostructured surface of paraffin impregnated graphite electrode (PIGE). Subsequently, we assembled SAM by choosing the 1-hexadecanethiole and mercaptoacetic acid. These two kinds of SAM underwent the functionalization by L-Tryptophan. The observations of silver on PIGE surfaces were performed by scanning electron microscope (SEM). For surface analysis of the SAM functionalized by L-tryphophan, the TOF-SIMS technique was chosen. Finally, the fragmented ions of the immobilized-L-Tryptophan SAM were determined on the basis of suggested residues and three-dimensional structure. The residues show that the ability of L-Tryptophan to build homogeneous structure is better by mercaptoacetic acid SAM structure than by 1-hexadecanethiol. It was observed that L-Tryptophan built compact surface, which, due its chemical properties, can represent very interesting side regarding biocompatibility, homochirality and robustness in the area of life science.\u0000","PeriodicalId":9888,"journal":{"name":"Central European Journal of Chemistry","volume":"19 1","pages":"568-576"},"PeriodicalIF":0.0,"publicationDate":"2014-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75328161","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

50 years of superbases made from organolithium compounds and heavier alkali metal alkoxides 50年来由有机锂化合物和较重的碱金属醇氧化物制成的超碱

Central European Journal of Chemistry Pub Date : 2014-02-21 DOI: 10.2478/s11532-014-0528-0

L. Lochmann, M. Janata

{"title":"50 years of superbases made from organolithium compounds and heavier alkali metal alkoxides","authors":"L. Lochmann, M. Janata","doi":"10.2478/s11532-014-0528-0","DOIUrl":"https://doi.org/10.2478/s11532-014-0528-0","url":null,"abstract":"AbstractA review of reactions of organolithium compounds (RLi) with alkali metal alkoxides is presented. On the one hand, simple lithium alkoxides form adducts with RLi the reactivity of which differs only slightly from that of RLi. On the other hand, after mixing heavier alkali metal alkoxides (R’OM, M = Na, K, Rb, Cs) with RLi, a new system is formed, which has reactivity that dramatically exceeds that of the parent RLi. A metal interchange, according to the equation RLi + R’OM = RM + R’OLi, occurs in this system, giving rise to a superbase. This reaction is frequently used for the preparation of heavier alkali metal organometallic compounds. Similar metal interchange takes place between R’OM and compounds such as lithium amides and lithium enolates of ketones or esters, thus demonstrating the general nature of this procedure. Superbases react easily with many types of organic compounds (substrates), resulting in the formation of a heavier alkali metal derivative of the substrate (metalation). The metalated substrate can react in situ with an electrophile to yield the substituted substrate, a procedure that is frequently used in synthetic and polymer chemistry. An improved mechanism of metal interchange and reaction of superbases with substrates is proposed.\u0000","PeriodicalId":9888,"journal":{"name":"Central European Journal of Chemistry","volume":"18 1","pages":"537-548"},"PeriodicalIF":0.0,"publicationDate":"2014-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83278224","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: 44

Microwave assisted extraction of essential oils from enzymatically pretreated lavender (Lavandula angustifolia Miller) 微波辅助萃取酶处理薰衣草精油的研究

Central European Journal of Chemistry Pub Date : 2014-02-20 DOI: 10.2478/s11532-014-0532-4

I. Călinescu, A. Gavrila, M. Ivopol, G. Ivopol, M. Popescu, Nectara Mircioaga

{"title":"Microwave assisted extraction of essential oils from enzymatically pretreated lavender (Lavandula angustifolia Miller)","authors":"I. Călinescu, A. Gavrila, M. Ivopol, G. Ivopol, M. Popescu, Nectara Mircioaga","doi":"10.2478/s11532-014-0532-4","DOIUrl":"https://doi.org/10.2478/s11532-014-0532-4","url":null,"abstract":"In this study, microwave assisted a hydrodistillation process (MWHD) of essential oils from lavender (Lavandula angustifolia Miller) was investigated. In order to examine any potential differences in essential oil extraction, the lavender flowers underwent enzymatic pretreatment.A 23 factorial design of experiments, combined with statistical methods of data analysis were used to optimize enzymatic pretreatment and to evaluate the influence of major variables (enzyme concentration, temperature and pH) on the performance of the microwave assisted extraction.Under optimal conditions, an extraction yield of 24 mg oil g−1 substrate was achieved (an increase by approximately 25% in comparison with the classic extraction conditions of conventional hydrodistillation).The main compounds of the essential oils obtained were analyzed and identified by gas chromatography coupled to mass spectrometry (GC-MS). Analyzing the data obtained indicated that the content of main compounds (linalool and linalyl acetate − 73%) was greater than that obtained by conventional extraction (67%).","PeriodicalId":9888,"journal":{"name":"Central European Journal of Chemistry","volume":"16 1","pages":"829-836"},"PeriodicalIF":0.0,"publicationDate":"2014-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74795758","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: 25

Obtaining and characterizing modified tannins by physical-chemical methods 用物理化学方法制备改性单宁并对其进行表征

Central European Journal of Chemistry Pub Date : 2014-02-08 DOI: 10.2478/s11532-014-0505-7

A. Gonţa, T. Lupascu, N. Timbaliuc, A. Meghea

引用次数: 2

Influence of temperature on the reduction kinetics of Bi(III) ion in the presence of cystine in chlorate (VII) solutions of decreased water activity 温度对水活度降低的氯酸盐(VII)溶液中胱氨酸存在下Bi(III)离子还原动力学的影响

Central European Journal of Chemistry Pub Date : 2014-02-01 DOI: 10.2478/s11532-013-0376-3

A. Nosal-Wiercińska

引用次数: 2

DFT calculation and assignment of vibrational spectra of aryl and alkyl chlorophosphates 芳基和烷基氯磷酸盐振动谱的DFT计算和赋值

Central European Journal of Chemistry Pub Date : 2014-02-01 DOI: 10.2478/s11532-013-0359-4

V. Anishchenko, V. I. Rybachenko, K. Chotiy, A. Redko

引用次数: 0