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Naphtha is the feedstock for steam cracking and catalytic reforming of aromatics. Based on the molecular library and 42 groups of practical data including the properties of density, potential aromatic content, the weight fractions of PNA and carbon number distribution, a molecular reconstruction model for naphtha was established by maximum information entropy method. The content of 451 components for naphtha were estimated. The molecular composition generated by the simulation is in good agreement with the practical data. The model can provide the referential value for the steam cracking and catalytic reforming of aromatics processes at molecular level. [ABSTRACT FROM AUTHOR]

Highlights • Various methods are distinguished by the framework of molecular representation. • The method to determine molecular abundance is another distinction. • The deterministic models are relatively limited to the lighter fractions. • The stochastic models are more pertinent to the heavier fractions. • Analytical data is the foundation for the development of molecular reconstruction. Abstract Molecular reconstruction is popular in current oil refinery modeling. It aims to understand the refining process from the molecular level, to predict product properties accurately, to optimize the processes, and to increase the value of each molecule. Molecular reconstruction technique determines the detailed molecular composition of petroleum fractions through obtainable bulk properties and chemical details. In this paper, the existing molecular reconstruction models involving models with a set of predefined deterministic molecules, stochastic reconstruction method, structure-oriented lumping method, molecular type-homologous series matrix method, reconstruction by entropy maximization method, stochastic reconstruction-entropy maximization method and state space representation method are reviewed and compared. The credibility of the simulated composition and the drawbacks of molecular reconstruction technique are also discussed. [ABSTRACT FROM AUTHOR]

A high performance liquid chromatographic method utilizing an immobilized artificial membrane (IAM HPLC) column has been developed to separate the members of a library containing 38 aurone and thioaurone type structures and to characterise their lipophilicity. The experimental lipophilicity data (k'IAM) have been compared with the previously determined ones C8(MOS) column (k'MOS) and with their calculated lipophilicity parameters (CLOGP). In general, good correlations between the measured and calculated lipophilicities have been found both for the IAM and MOS column. The IAM column showed higher efficiency in separation of isomeric aurones or thioaurones than the MOS one and, consequently, it showed higher potential in differentiation of their lipophilicities. Our findings proved the usefulness of the HPLC method in fast characterisation of the lipophilicity of drug candidates closely related in structure. [ABSTRACT FROM AUTHOR]

A bacteria library was constructed from the caecum of a rabbit maintained under standard conditions. The complete gene 16S rRNA gene was sequenced. The 228 clones obtained were distributed in 70 operational taxonomic units (OTUs). The large majority of the OTUs were composed of one or two clones and seven OTUs contained half of the sequences. Fourteen sequences had high similarity to the sequence already registered in databases (threshold of 97%). Only one of these sequences has been identified as Variovorax sp. (99% identity). Units were distributed mainly (94%) in the Firmicutes phylum. Three sequences were related to Bacteroidetes. Nine clusters were defined in the phylogenic tree. A great diversity of caecal bacteria of the rabbit was shown. Half of the sequences generated in this library were distributed in the phylogenetic tree near the sequences characterized previously in rabbit caecum (potential core species), and the other half of the sequences were well separated (satellite species). [ABSTRACT FROM AUTHOR]

Abstract: High performance liquid chromatographic (HPLC) method has been developed to separate the members of a library including 24 benzylidenecycloalkanone-type structures and to characterize their lipophilicity. The experimental lipophilicity data (k) of the compounds have been compared with their calculated lipophilicity parameters (CLOGP). In general, good correlations between the measured and calculated lipophilicities have been found and these results were in good accordance with our previously data obtained in case of structurally related molecular libraries. In addition, cytotoxicity screening has been performed to determine the antiproliferative activity of these compounds. Some of the investigated compounds possessed noticeable inhibitory potential. Based on the correlation between the antiproliferative activity and experimentally determined lipophilicity of the molecules investigated, limited structural demands to obtain more potent compounds can be exhibited to support the synthetic design. [Copyright &y& Elsevier]

Abstract: A molecular library based on E-2-arylmethylene-1-tetralone has been designed and synthesized. A reversed phase high performance liquid chromatographic (RP-HPLC) method has been developed and applied to separate them and to characterize their lipophilicity. The chromatographic method applied here was suitable to separate the structural (ortho and para) isomers of compounds and was sensitive enough to differentiate their lipophilicities. The measured (k′) and computer calculated (CLOGP) lipophilicity values has been compared. Good linear correlation has been found in the case of these structurally related molecules. In vitro biological assay has been performed with Methylene blue dying to investigate the antiproliferative potency of the compounds synthesized in this work. The measured (k′) and calculated (CLOGP) lipophilicities of the compounds were compared with the antiproliferative activities and an optimum value of lipophilicity has been found for these compounds. [Copyright &y& Elsevier]