Monitoring structural transformations in crystals. 13. On photocyclization in 2,3,4,5,6‐pentamethylbenzophenone, 1,3‐diphenylbutan‐1‐one and 2,4,6‐triisopropyl‐4′‐methoxybenzophenone

The geometrical parameters governing the potential for the photocyclization reaction occurring in crystals of 2,3,4,5,6‐pentamethylbenzophenone, C₁₈H₂₀O, (I), 1,3‐diphenylbutan‐1‐one, C₁₆H₁₆O, (II), and 2,4,6‐triisopropyl‐4′‐methoxybenzophenone, C₂₃H₃₀O₂, (IV), have been evaluated. Compound (IV) undergoes photocyclization but (I) and (II) do not, despite the fact that their geometrical parameters appear equally favourable for reaction. The structure of the partially reacted crystal of the photoactive compound, i.e. 2,4,6‐triisopropyl‐4′‐methoxybenzophenone–3,5‐diisopropyl‐7‐(4‐methoxyphenyl)‐8,8‐dimethylbicyclo[4.2.0]octa‐1,3,5‐trien‐7‐ol (9/1), 0.90C₂₃H₃₀O₂·0.10C₂₃H₃₀O₂, (III), was also determined, providing structural evidence for the reactivity of the compound. It has been found that the carbonyl group of the photoactive compound reacts with one of the two o‐isopropyl groups. The study has shown that the intramolecular geometrical parameters are not the only factors influencing the reactivity of compounds in crystals.     

Breakdown of the reduction of the rovibrational Hamiltonian: The case of SO2F2

The ground state rotational spectrum of the near-spherical top molecule S¹⁸O₂F₂ (sulfuryl fluoride) has been measured from 50 to 700 GHz. As for the parent isotopologue, S¹⁶O₂F₂ [K. Sarka, J. Demaison, L. Margulès, I. Merke, N. Heineking, H. Bürger, H. Ruland, J. Mol. Spectrosc. 200 (2000) 55-64], it was necessary to use a non-reduced Hamiltonian in order to obtain a satisfactory fit. It was possible to determine six quartic centrifugal distortion constants (instead of five for a standard asymmetric top) and five sextic constants (one of them not existing in the reduced Hamiltonian) could also be determined. This ground state level has also been analysed thanks to a tensorial formalism developed in Dijon. Only two tensorial sextic constants are fixed to zero, all others have been adjusted. Although S¹⁸O₂F₂ is less spherical than S¹⁶O₂F₂, the analysis was more difficult. It is partly due to the fact that S¹⁸O₂F₂ is oblate whereas S¹⁶O₂F₂ is prolate. The experimental quartic centrifugal distortion constants were found in good agreement with those calculated from the force field, confirming the correctness of the analysis.     

An alternative approach to the synthesis of [1,2,4]triazolo[1,5-a]pyridine-8-carbonitriles,their crystal structure,and DFT calculations

New representatives of [1,2,4]triazolo[1,5-a]pyridine-8-carbonitriles were synthesized via the condensation of β-diketones or β-dialdehydes and characterized using MS spectrometry, ¹H, ¹³C and, ¹⁹F NMR and IR spectroscopy. Crystal structures of two compounds were established using X-ray analysis and showed that title compounds are prone to the formation of planar molecules. The absence of band responsible for CN stretching vibration in trifluoromethyl-containing compounds was explained using the DFT calculations method, which also showed a significant influence of fluorines introducing on the energy gap between HOMO and LUMO.     

Aronia melanocarpa (Michx.) Elliot,Chaenomeles superba Lindl. and Cornus mas L. Leaf Extracts as Natural Preservatives for Pork Meat Products

The aim of this study was to investigate the possibility of using Aronia melanocarpa, Chaenomeles superba, and Cornus mas leaf extracts as natural preservatives for pork meat products. Pork sausages were stored in modified atmosphere packaging (MAP) (80% N₂ and 20% CO₂) at 4 °C for 29 days. The total psychrotrophic counts (TPC) were determined during the storage period, along with the numbers of Enterobacteriaceae and lactic acid bacteria (LAB). The extracts improved the microbial quality of the meat products but to a lesser extent than sodium nitrate (III). They reduced the amounts of Enterobacteriaceae and LAB. The A. melanocarpa leaf extract showed the strongest preservative effect. The bacterial biodiversity of the meat products was investigated based on high-throughput sequencing of the 16S rRNA gene. Two predominant bacteria phyla were identified, Proteobacteria and Firmucutes, mostly consisting of genera Photobacterium, Brochothrix, and Carnobacterium. The extracts also influenced microbial community in sausages decreasing or increasing bacterial relative abundance. The extracts significantly inhibited lipid oxidation and improved the water-holding capacity of the meat, with C. superba extract showing the strongest influence. In addition, A. melanocarpa and C. superba improved the redness (a*) of the sausages. The results of this study show that A. melanocarpa, C. superba, and C. mas leaf extracts can extend the shelf life of meat products stored in MAP at 4 °C.     

Method validation for determination of amino acids in feed by UPLC

Accreditation and Quality Assurance - The paper presents results of validation of an analytical procedure based on ultra-performance liquid chromatography technique (UPLC) for determination of 17...     

Construction of 3D models of the CYP11B family as a tool to predict ligand binding characteristics

Aldosterone is synthesised by aldosterone synthase (CYP11B2). CYP11B2 has a highly homologous isoform, steroid 11β-hydroxylase (CYP11B1), which is responsible for the biosynthesis of aldosterone precursors and glucocorticoids. To investigate aldosterone biosynthesis and facilitate the search for selective CYP11B2 inhibitors, we constructed three-dimensional models for CYP11B1 and CYP11B2 for both human and rat. The models were constructed based on the crystal structure of Pseudomonas Putida CYP101 and Oryctolagus Cuniculus CYP2C5. Small steric active site differences between the isoforms were found to be the most important determinants for the regioselective steroid synthesis. A possible explanation for these steric differences for the selective synthesis of aldosterone by CYP11B2 is presented. The activities of the known CYP11B inhibitors metyrapone, R-etomidate, R-fadrazole and S-fadrazole were determined using assays of V79MZ cells that express human CYP11B1 and CYP11B2, respectively. By investigating the inhibitors in the human CYP11B models using molecular docking and molecular dynamics simulations we were able to predict a similar trend in potency for the inhibitors as found in the in vitro assays. Importantly, based on the docking and dynamics simulations it is possible to understand the enantioselectivity of the human enzymes for the inhibitor fadrazole, the R-enantiomer being selective for CYP11B2 and the S-enantiomer being selective for CYP11B1.     

Contractivity properties of Ornstein-Uhlenbeck semigroup for general commutation relations

We study a certain class of von Neumann algebras generated by selfadjoint elements ω_i=a_i+a_i⁺, where a_i, a_i⁺ satisfy the general commutation relations:We assume that operator T for which the constants are matrix coefficients satisfies the braid relation. Such algebras were investigated in [BSp] and [K] where the positivity of the Fock representation and factoriality were shown. In this paper we prove that T-Ornstein-Uhlenbeck semigroup U_t=Γ_T(e^−t), t>0 arising from the second quantization procedure is hyper- and ultracontractive. The optimal bounds for hypercontractivity are also discussed.This paper was partially supported by KBN grant no 2P03A00732 and also by RTN grant HPRN-CT-2002-00279.     

New Polyfluorinated Cyanine Dyes for Selective NIR Staining of Mitochondria

In this communication, the synthesis of three unknown polyfluorinated cyanine dyes and their application as selective markers for mitochondria are presented. By incorporating fluorous side chains into cyanine dyes, their remarkable photophysical properties were enhanced. To investigate their biological application, several different cell lines were incubated with the synthesized cyanine dyes. It was discovered that the presented dyes can be utilized for selective near-infrared-light (NIR) staining of mitochondria, with very low cytotoxicity determined by MTT assay. This is the first time that polyfluorinated cyanine fluorophores are presented as selective markers for mitochondria. Due to the versatile applications of polyfluorinated fluorophores in bioimaging and materials science, it is expected that the presented fluorophores will be stimulating for the scientific community.     

Modification of blood serum DSC profiles by sauna treatments in cross-country skiers during the exercise cycle

Journal of Thermal Analysis and Calorimetry - The study has evaluated the effect of sauna treatments on the blood serum of professional cross-country skiers (3 women and 6 men) during two exercise...