Internalization of (bis)phosphonate-modified cellulose nanocrystals by human osteoblast cells

Covalent conjugation of (bis)phosphonate group-containing molecules, sodium Alendronate (Aln) and 3-AminoropylPhosphoric Acid (ApA), to Cellulose nanocrystals (CNCs) was performed via oxidation/Shiff-base reaction. Further fluorescent labelling with Rhodamine B Iso ThioCyanate (RBITC) was performed to follow CNCs interaction and potential internalization with/in human osteoblasts by confocal microscopy. Complementary analyses were applied to identify the conjugation (Atenuated Total Reflectance–Fourier Transform Infrared and UV–VIS spectroscopies), physico-chemical (Dynamic Light Scattering and Nanoparticle Tracking Analysis) and morphological (Transmission Electron Microscopy) features of native and ApA/Aln-modified CNCs in physiologically relevant environments (Phosphate Buffer Saline, Advanced Dulbecco’s Modified Eagle Medium). While conjugation did not affect the CNCs` size, the RBITC-labelling promotes their aggregation. Faster (1 h vs. 2 h) uptake by osteoblasts of RBITC-CNCoxAln, compared to RBITC-CNCoxApA, and no-internalization (in 24 h) of native RBITTC-CNC, indicate a higher affinity of Aln-modified CNCs to the cells, while all CNCs (in 0.25–0.06 wt%) promote the cell growth. Aln/Apa-modified CNCs shows high potential in drug-delivery for bone therapies, and theranostics.     

Molecular and cellular approach in the study of antioxidant/pro-oxidant properties of Micromeria croatica (Pers.) Schott

Phytochemical composition and antioxidant activity of three wild populations of endemic Illyric-Balcanic species Micromeria croatica (Pers.) Schott have been evaluated with respect to plant organ and growing location. Multivariate analysis (principal component analysis) was performed to visualise (dis-)similarity among samples and identify the correlations between phytochemical variables that explain the most variability. The tested leaf extract from Ba?i? kuk locality exhibited protective effects against reactive oxygen species-induced damage of DNA and inhibition of lipid peroxidation, while it caused oxidative degradation of protein in the bovine serum albumin assay at higher concentrations. This extract also exhibited cytotoxic activity and facilitated the formation of reactive oxygen species in the HEp2 cell line, in a dose-dependent manner.     

Nonlinear deformation of Three-Component Composites

The model of nonlinear deformation of stochastic composites under microdamaging is developed for the case of threecomponent composite, when the microdamages are accumulated in the matrix. The composite is treated as isotropic matrix strengthened by two different types of spheroidal inclusions with transversally-isotropic symmetry of elastic properties. Fractured microvolumes are modeled by a system of randomly distributed quasispherical pores. The porosity balance equation and relations for determining the effective elastic modules for the case of transversally-isotropic components are taken as basic relations. The fracture criterion is assumed to be given as the limit value of the intensity of average shear stresses occurring in the undamaged part of the material. The algorithm for determination of nonlinear deformative properties of such a material is constructed. The nonlinear stress-strain diagrams for three-component concrete for the case of uniaxial tension are obtained. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Collision-induced dissociation of a series of coumarins studied by positive- and negative-ion electrospray triple quadrupole tandem mass spectrometry

Aryl-substituted 4-hydroxycoumarins (1-57) were investigated by electrospray ionisation (ESI) mass spectrometry. Their fragmentation in the ion source or in the collision cell of a triple quadrupole mass spectrometer was investigated. The effect of the substituents in the aromatic ring on the fragmentation of the 4-hydroxycoumarin derivatives is shown. The influence of the tautomerism on the formation of quasimolecular ions and mass spectral fragmentation was explained. Mass spectral studies on some deuterated compounds proved some of the proposed fragmentation pathways. Results obtained are very useful in the process of detection and characterisation of 4-hydroxycoumarins, as well as for structural elucidation of their more complex derivatives.     

Preparation and Characterization of Oil Containing Microcapsules Obtained by an Interaction Induced Coacervation

A novel method for microencapsulation of oil by coacervation is presented. The method employs segregative phase separation between sodium carboxymethyl cellulose (NaCMC) and a complex of hydroxypropylmethyl cellulose (HPMC) and sodium dodecylsulfate (SDS), which results in coacervate formation. Microstructural properties of the coacervate can be varied by tuning NaCMC-HPMC/SDS interaction, which is achieved by changing SDS concentration. Microcapsules preparation route is presented. Encapsulation efficiency and dispersion properties of microcapsules with coacervate shell of different properties and different oil content were tested. Microcapsules with smallest droplet size, the narrowest droplet size distribution, and with lowest extractability of encapsulated oil were obtained when NaCMC-HPMC/SDS interaction results in formation of the most compact coacervate shell, no matter of the encapsulated oil.     

Tailoring of multifunctional cellulose fibres with “lotus effect” and flame retardant properties

This research aimed to create multifunctional cellulose fibres with water- and oil-repellent, self-cleaning, and flame retardant properties. A sol mixture of fluoroalkyl-functional siloxane, organophosphonate and methylol melamine resin was applied to cotton fabric by the pad-dry-cure method. Successful coating was verified by atomic force microscopy and Fourier transform infrared spectroscopy. The functional properties of the coated fibres were investigated using the static contact angles of water and n-hexadecane, the water sliding angles, the vertical test of flammability, the limiting oxygen index, and simultaneous thermal analysis. The results reveal that a homogeneous composite inorganic–organic polymer film formed on the cotton fabric surface exhibited the following properties: static contact angle of water of 150° and of n-hexadecane of 128°, water sliding angle of 10°, limiting oxygen index of 34 %, and high thermal stability. These results demonstrate the synergistic activity of the compounds in the coating, which resulted in the creation of a “lotus effect” on the fabric surface as well as excellent flame retardancy and thermal stability.     

2,3-Dihydro-1H-1,5-benzodiazepines: A conversion of thiolactams to amidines

Summary The synthesis of a new series of diversely N-4 substituted amidines of 2,3-dihydro-1H-1,5-benzodiazepine has been accomplished starting from tetrahydro-1,5-benzodiazepin-2-one derivatives. These compounds were transformed into the desired thiolactams2a–i which reacted in the presence of mercuric chloride with ammonia, as well as primary or secondary amines to give amidines3a–i. Hydrazidines3j–l were prepared by treatment of thiolactams with an excess of hydrazine.

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2,3-Dihydro-1H-1,5-benzodiazepine: Umwandlung von Thiolactamen in Amidine

Zusammenfassung Einige neue N-substituierte Amidine von 2,3-Dihydro-1H-1,5-benzodiazepinen wurden ausgehend von Tetrahydro-1H-1,5-benzodiazepin-2-onen synthetisiert. Letztere wurden in die Thiolactame2a–i umgewandelt und anschließend durch Behandeln mit Ammoniak, primären oder sekundären Aminen in Gegenwart von Quecksilber(II)-chlorid zu den entsprechenden Amidinen3a–i umgesetzt. Die Hydrazinoamidine3j–l wurden aus den Thiolactamen mit Hydrazineüberschuß erhalten.

     

Functional Modification of Cellulose Acetate Microfiltration Membranes by Supercritical Solvent Impregnation

This study investigates the modification of commercial cellulose acetate microfiltration membranes by supercritical solvent impregnation with thymol to provide them with antibacterial properties. The impregnation process was conducted in a batch mode, and the effect of pressure and processing time on thymol loading was followed. The impact of the modification on the membrane’s microstructure was analyzed using scanning electron and ion-beam microscopy, and membranes’ functionality was tested in a cross-flow filtration system. The antibiofilm properties of the obtained materials were studied against Staphyloccocus aureus and Pseudomonas aeruginosa, while membranes’ blocking in contact with bacteria was examined for S. aureus and Escherichia coli. The results revealed a fast impregnation process with high thymol loadings achievable after just 0.5 h at 15 MPa and 20 MPa. The presence of 20% of thymol provided strong antibiofilm properties against the tested strains without affecting the membrane’s functionality. The study showed that these strong antibacterial properties could be implemented to the commercial membranes’ defined polymeric structure in a short and environmentally friendly process.     

Synthesis,spectral characterization and inhibitory potency of ferrocene‐containing mannosides towards type 1 fimbriated Escherichia coli

Escherichia coli adhesion to the bladder epithelium is mediated through recognition of the tissue‐surface mannosylated proteins with bacterial lectin FimH. The inhibition of this recognition‐dependent interaction has been recognized as a promising strategy for the development of an anti‐adhesion therapy. Mannosides with either aryl‐ or elongated alkyl‐functionalized aglycon portions have been shown to be potent inhibitors of FimH‐mediated adhesion. Thus, we have synthesized four mannose‐based bioorganometallics containing an extended alkyl chain between sugar and ferrocene components connected via ester linkage ( 14 (n = 4) and 15 (n = 5)) or amide linkage ( 18 (n = 3) and 19 (n = 4)). The novel bioconjugates were characterized using infrared and NMR (¹H, ¹³C, COSY, NOESY, HSQC, HMBC) spectroscopies, electrospray ionization mass spectrometry and high‐resolution mass spectrometry. Hemagglutination inhibitory assay of the novel bioorganometallics revealed an enhanced inhibitory potential in comparison to methyl α‐d ‐mannoside. Thereby, the bioconjugate 19 exhibited a twofold increase in inhibitory activity compared with 14 , 15 and 18 . Copyright © 2016 John Wiley & Sons, Ltd.     

On the reaction of 3-nitro-1,2-phenylenediamine with ethyl acetoacetate. Condensed dihydrodiazepinones

Condensation of 3-nitro-1,2-phenylenediamine with ethyl acetoacetate in boiling xylene gave two isomeric 2,3-dihydro-4-methyl-9-nitro- and 2,5-dihydro-4-methyl-6-nitro-1H-1,5-benzodiazepin-2-ones, the 9-nitro derivative thermal rearrangement product N-isopropenyl-4-nitrobenzimidazolone and a non cyclic acetoacetamide derivative. At room temperature these reactants afforded 2,3-dihydro-2-ethoxycarbonyl-methyl-2-methyl-4-nitrobenzimidazole.