Analysis of galactoglucomannans from spruce wood by capillary electrophoresis

The aim of this study was to setup a method for detection and quantification of monosaccharide components in technical galactoglucomannas (T-GGM) from spruce wood using capillary zone electrophoresis (CZE). CZE technique was optimised regarding borate buffer concentrations, EOF modifier application, and system pH. Aqueous solution of T-GGM was chemically hydrolysed by sulphuric acid, in an autoclave. In this way obtained monosaccharides were derivatized with 4-amino benzoic acid ethyl ester via reductive amination using sodium cyanoborohydride. The results of the optimisation procedure showed that the borate buffers at lowest concentrations (100 and 200 mM) with acetonitrile addition as EOF modifier gave the optimal measurement results, as it showed sufficient separation at relatively short migration times. The amounts of single monosaccharide components in the T-GGM samples obtained by the optimised CZE procedure were practically the same in comparison to the results of the well established HPLC-anion exchange chromatography. On the basis of this research, it was concluded that the capillary zone electrophoresis is an efficient analytical procedure for the characterisation of galactoglucomannans derived from softwoods.     

Cohomology of Pure Braid Groups of exceptional cases

Consider the ring R:=Q[τ,τ−1] of Laurent polynomials in the variable τ. The Artin's Pure Braid Groups (or Generalized Pure Braid Groups) act over R, where the action of every standard generator is the multiplication by τ. In this paper we consider the cohomology of these groups with coefficients in the module R (it is well known that such cohomology is strictly related to the untwisted integral cohomology of the Milnor fibration naturally associated to the reflection arrangement). We compute this cohomology for the cases I₂(m), H₃, H₄, F₄ and An with 1?n?7.     

Synthesis and characterization of bis(indenyl) zirconium aryloxide derivatives and their use in α‐olefin polymerization

A series of new bis(indenyl) zirconium diaryloxides of general formula Ind₂Zr(OL)₂ (L = C₆H₅, 2 ; C₆F₅, 3 ; 2,6‐Me₂C₆H₃, 4; 2,4,6‐Me₃C₆H₂, 5 ; 4‐^tBuC₆H₄, 6 ) were synthesized by a metathesis reaction of Ind₂ZrCl₂ ( 1 ) with the appropriate thallium aryloxide salt, TlOL. The complexes 1–6 were characterized by ¹H and ¹³C NMR techniques. They were also examined as catalysts for ethene and 1‐hexene polymerization with methylalumoxane as co‐catalyst, and a trend of the polymerization activity as a function of aryloxide ligands was observed. An interpretation of this trend, considering both the electronic and steric effects of the substituents on the aryloxide rings, was proposed. Copyright © 2001 John Wiley & Sons, Ltd.     

New jaspamide derivatives with antimicrofilament activity from the sponge Jaspis splendans

A reinvestigation of Jaspis splendans afforded the novel compounds jaspamide D-G plus the known compounds jaspamide and jaspamides B and C. All compounds exhibited potent cytotoxic activities and were shown to cause microfilament disruption. Biological activity and structural elucidation are reported here.     

Synthesis and properties of [1,6′]biazulenyl compounds

The synthesis of a new biazulenyl system, which contains azulene moieties coupled in 1- and 6-position is reported. The structure of the isolated compounds, as well as the calculated dihedral angle between the planes of the coupled moieties, has been correlated with the recorded spectra.     

Theoretical and vibrational spectral investigation of sodium salt of acenocoumarol

The FT‐IR and FT‐Raman spectra of sodium salt of 4‐hydroxy‐3[1‐(4‐nitrophenyl)‐3‐oxobutyl]‐2H‐1‐benzopyran‐2‐one (acenocoumarol sodium salt) in solid phase have been recorded and analyzed. The optimization geometry, intramolecular hydrogen bonding, and harmonic vibrational wavenumbers of acenocoumarol sodium salt have been investigated with the help of B3LYP density functional theory (DFT) methods. The infrared and Raman spectra were predicted theoretically from the calculated intensities. Natural bond orbital (NBO) analysis indicates the presence of C H···O hydrogen bonding in the molecule. The first static hyperpolarizability of the molecule has been computed. Copyright © 2009 John Wiley & Sons, Ltd.     

Process‐Scale Total Synthesis of Nature‐Identical (−)‐(S,S)‐7‐Hydroxycalamenal in High Enantiomeric Purity through Catalytic Enantioselective Hydrogenation

A process‐scale stereoselective synthesis of nature‐identical (−)‐(S,S)‐7‐hydroxycalamenal (=(−)‐(5S,8S)‐5,6,7,8‐tetrahydro‐3‐hydroxy‐5‐methyl‐8‐(1‐methylethyl)naphthalene‐2‐carbaldehyde; (−)‐ 1a ) in 96% enantiomeric excess (ee) with the aid of chiral Ru complexes has been developed. The key step was the enantioselective hydrogenation of easily accessible 2‐(4‐methoxyphenyl)‐3‐methylbut‐2‐enoic acid ( 10 ) to (+)‐ 11 in a 86% ee (Scheme 5 and Table 1). A substantial increase in optical purity (96% ee) was achieved by induced crystallization of the intermediate (+)‐3,4‐dihydro‐4‐(1‐methylethyl)‐7‐methoxy‐2H‐naphthalen‐1‐one ((+)‐ 3 ). Computational conformation analysis carried out on the analog (−)‐ 9 rationalized the high diastereoselectivity achieved in the catalytic hydrogenation of the CC bond.     

pH‐Responsive Hybrid Organic–Inorganic Ruthenium Nanoparticles for Controlled Release of Doxorubicin

The current study aims at preparing biocompatible hybrid organic–inorganic ruthenium core–shell nanostructures (RuNPs) coated with polyvinylpyrrolidone (PVP) and polyoxyethylene stearate (POES). Thereafter, the core/shell RuNPs are loaded with doxorubicin (to form RuPDox) with a loading efficiency > 60%. RuPDox possesses exceptional stability and pH‐responsive release kinetics with approx. 50% release of doxorubicin at up to 1 h exposure to an acidic endosomal environment. The cytotoxic effects of RuPDox are tested in vitro against breast cancer (MDA‐MB‐231), ovarian cancer (A2780), and neuroblastoma (UKF‐NB‐4) cells. Notably, although RuNPs have slight cytotoxicity only, RuPDox causes a synergistic enhancement of cytotoxicity when compared to free doxorubicin. Significant increase in free radicals formation, enhanced activity of executioner caspases 3/7, and higher expression of p53 and metallothionein is further identified due to the RuPDox treatment. Single‐cell gel electrophoresis reveals no additional contribution of RuNPs to genotoxicity of doxorubicin. Moreover, RuPDox promotes significantly increased stability of doxorubicin in human plasma and pronounced hemocompatibility assayed on human red blood cells. The results imply a high potential of biocompatible hybrid RuNPs with PVP‐POES shell as versatile nanoplatforms to enhance the efficiency of cancer treatment.     

An Artificial Disc: Chemical and Biomechanical Analysis

Summary: Degeneration of intervertebral discs is the most common cause of back pain. The first phase of this degenerative process involves the nucleus pulposus. A rapid recovery of this structure can prevent further degradation of the annulus fibrosus. Guar Gum is an hydrophilic polysaccharide extracted from the seed endosperm of a plant. Through a cross-linking procedure a Guar hydrogel was synthesized. The Guar hydrogel could be injected by a syringe and it is a good candidate as a nucleus pulposus substitute. For the preparation of the artificial fibrosus annulus, commercially available polymer materials are tuned to achieve suitable mechanical properties. To achieve this peculiar behaviour, the main strategy investigated is the dispersion of hollow polymer micro spheres in a thermoplastic polymer matrix. Processing conditions and particle content are finely tuned to get the target mechanical behaviour.