Analysis of oversulfation in a chondroitin sulfate oligosaccharide fraction from bovine aorta by nanoelectrospray ionization quadrupole time-of-flight and fourier-transform ion cyclotron resonance mass spectrometry

A combination of negative ion nano-electrospray ionization Fourier-transform ion cyclotron resonance and quadrupole time-of-flight mass spectrometry was applied to analysis of oversulfation in glycosaminoglycan oligosaccharides of the chondroitin sulfate type from bovine aorta. Taking advantage of the high-resolution and high mass accuracy provided by the FT-ICR instrument, a direct compositional assignment of all species present in the mixture can be obtained. An oligosaccharide fraction containing mainly hexasaccharides exhibited different levels of sulfation, indicated by the presence of species with regular sulfation pattern as well as oversulfated oligosaccharides with one additional sulfate group. Oversulfation can be directly identified from the high-resolution/high mass accuracy FT-ICR mass spectra according to their specific isotopic fine structure. Location of sulfate groups was analyzed by Q-TOF MS and low-energy CID MS/MS. Tetrasulfated hexasaccharides were analyzed by use of collision-induced dissociation at variable collision energy for an unambiguous assignment of the attachment site of the sulfate groups by minimizing unspecific neutral losses. Cleavage of glycosidic bonds gave rise to B- and C-type ions and their respective complementary Y- and Z-type fragment ions.     

Gangliosidome of a Human Hippocampus in Temporal Lobe Epilepsy Resolved by High-Resolution Tandem Mass Spectrometry

In this study, we developed a high-resolution tandem mass spectrometry (HR MS) approach to assess presumed changes in gangliosidome of a human hippocampus affected by temporal lobe epilepsy (TLE) in comparison with a normal hippocampus. Gangliosides, membrane glycolipids, are particularly diverse and abundant in the human brain, and participate in ion transport and modulation of neuronal excitability. Changes in structural ganglioside pattern potentially linked to TLE molecular pathogenesis have not been explored in detail. Aiming to characterize TLE-specific gangliosidome, we analyzed the native gangliosides purified from a human hippocampal tissue sample affected by TLE and a control hippocampus using HR MS. Marked differences of ganglioside expression were shown in TLE vs. control, particularly with respect to the sialylation degree of components, discovered as a characteristic feature of TLE. Another major finding is the occurrence of tetrasialofucogangliosides in TLE and species modified by either O-acetylation or CH₃COO⁻. Structural analysis by higher-energy collisional dissociation (HCD) MS/MS gave rise to fragmentation patterns implying that the GQ1b (d18:1/18:0) isomer is specifically associated with TLE. Further investigation in a larger sample is needed in order to confirm the discovery of ganglioside structures specifically expressed in human TLE and to provide information on the probable role of gangliosides in the molecular events underlying seizures.     

Modulation of structure and dynamics of water under alternating electric field and the role of hydrogen bonding

Using Molecular Dynamics simulations, we investigate the effect of alternating (AC) electric field on static and dynamic properties of water. The central question we address is how hydrogen bonds respond to perpetual field-induced dipole reorientations. We assess structural perturbations of water network and changes of hydrogen bond dynamics in a range of alternating electric field strengths and frequencies using a non-polarisable water model, SPC/E, and two distinct polarisable models: SWM4-NDP and BK3. We confirm that AC field causes only moderate structural perturbations. Dynamic properties, including the rates of bond breaking, switching of hydrogen-bonding partners, and diffusion, accelerate with the strength of AC fields. All models reveal a nonmonotonic frequency dependence with fastest dynamics at frequencies around 200?GHz where the period of the field oscillation is commensurate with the average time it takes a typical proton to switch from one acceptor to another. Higher frequencies result in smaller amplitudes of angle oscillations and in reduced probability to complete the switch to another acceptor before the field reversal restores the original configuration. As frequency increases, these effects gradually weaken the influence of the field on the kinetics of hydrogen bonding and the associated rates of translational and rotational diffusion in water.     

Establishing the irradiation dose for paper decontamination

Museums, libraries and archives are preserving documents that are slowly degrading due to the inherent ageing of the cellulose substrate or to the technological errors of the past (acid paper, iron gall ink). Beside this, large quantities of paper are rapidly damaged by biological attacks following natural disasters and improper storage conditions.The treatment of paper documents with ionizing radiation can be used for mass decontamination of cultural heritage items but conservators and restaurators are still reserved because of the radiation induced degradation.We conducted a study for establishing the dose needed for the effective treatment of paper documents, taking into account the biological burden and the irradiation effects on paper structure. We used physical testing specific to paper industry and less destructive analytical methods (thermal analysis).Our results show that an effective treatment can be performed with doses lower than 10 kGy. Old paper appears to be less affected by gamma radiation than recent paper but the sampling is highly affected by the non-uniform degree of the initial degradation status. The extent of testing for degradation and the magnitude of acceptable degradation should take into account the biological threat and the expected life time of the paper documents.     

Nuclear Physics with 10 PW laser beams at Extreme Light Infrastructure – Nuclear Physics (ELI-NP)

The field of the uncharted territory of high-intensity laser interaction with matter is confronted with new exotic phenomena and, consequently, opens new research perspectives. The intense laser beams interacting with a gas or solid target generate beams of electrons, protons and ions. These beams can induce nuclear reactions. Electrons also generate ions high-energy photons via bremsstrahlung processes which can also induce nuclear reactions. In this context a new research domain began to form in the last decade or so, namely nuclear physics with high power lasers. The observation of high brilliance proton beams of tens of MeV energy from solid targets has stimulated an intense research activity. The laser-driven particle beams have to compete with conventional nuclear accelerator-generated beams. The ultimate goal is aiming at applications of the laser produced beams in research, technology and medicine. The mechanism responsible for ion acceleration are currently subject of intensive research in many laboratories in the world. The existing results, experimental and theoretical, and their perspectives are reviewed in this article in the context of IZEST and the scientific program of ELI-NP.     

High resolution mass spectrometric characterization of amino linked oligosaccharides — a preliminary study

In this study maltose, maltotriose and maltotetraose were for the first time, coupled to 4,4′-methylenedianiline (MDA). The aim of this preliminary work was to test the feasibility of oligo- and polysaccharide coupling to MDA and the characterization of the coupling products by high resolution mass spectrometry (MS). (+) nanoESI in combination with a quadrupole time of flight (QTOF) MS in full scan (MS) and MS/MS was optimized first on underivatized maltose, maltotriose and maltotetraose. The optimal screening and sequencing conditions were further applied to the MDA-functionalized oligosaccharides. The obtained results revealed a straightforward MS detection of the functionalized oligomers, high sequence coverage and a fragmentation pathway with the formation of B and Y ions as well as the complementary C and Z ions along with a typical cleavage of the aglycon. We consider that this methodology is fully applicable also to polydisperse mixtures of long chain polysaccharides, which due to the large number of components and their size require a systematic method of development and testing.      

Evolution of 2+ γ wave functions and gamma-stiffness in well-deformed rare-earth nuclei

The evolution of the structure of the gamma-vibrational band head 2⁺ _γ in well-deformed rare-earth nuclei is studied within the framework of RPA calculations using a quasiboson approximation based on the Nilsson model. The obtained evolution of the quasiparticle structure of the gamma-vibrational band head is shown to correlate well with the evolution of the same nuclei within the IBA symmetry triangle when described in the extended consistent-Q formalism. An empirical relation is presented that links the IBA parameter χ with the quasiparticle structure of the gamma-vibrational band head.     

Synthesis of oligomeric urethane dimethacrylates with carboxylic groups and their testing in dental composites

Carboxyl urethane dimethacrylate oligomers with poly(ethylene oxide) sequences in the structure were synthesized and examined in photopolymerizable resins that could better adhere to various kinds of materials, including tooth substrates. Aspects of the morphogenesis of dental composites formed through a photochemically initiated radical copolymerization of the carboxylic derivatives, in addition to other partners encountered frequently in such materials, were studied comparatively with the corresponding urethane dimethacrylate monomer. The effect of a small quantity of a carboxylic macromer (ca. 10%) on the formation of a network with a non‐carboxyl urethane dimethacrylate oligomer (90%) as a potential substitute for diglycidyl methacrylate of bisphenol A and a filler (1/1 70% Aerosil/glass) was visualized by fluorescence spectroscopy with a pyrene methanol probe. The results showed the following: (1) the degree of conversion in the formulations into which carboxyl urethane dimethacrylate was incorporated decreased with increasing poly(ethylene oxide) chain length, (2) the formation of excimers was inhibited in the derived composites, and (3) an important quenching of the monomer fluorescence emission with the UV–vis irradiation time was observed in the formulation containing a filler (Aerosil+Zr/Sr glass). Preliminary testing of the resin composites suggested that all urethane oligomers containing carboxylic acid could lead to dental materials with reduced polymerization shrinkage and good mechanical properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1956–1967, 2007     

Effective boson number calculations in Mo and Cd isotopes

The effects of the neutron-proton interaction on the low-lying levels of Mo and Cd isotopes have been considered in the frame of the IBA-1 model by taking into account an effective boson number (N _eff). Both an empirical procedure based on previous IBA-2 mixing calculations and theN _p N _n scheme provide comparableN _eff values. Level spectra and electromagnetic transitions are investigated. The results support the idea that IBA-1 calculations with a suitableN _eff can largely simulate IBA-2 mixing calculations, taking advantage of simplicity and a smaller number of parameters.     

The IZEST Framework

The past decade has seen a significant development of high energy laser facilities across Europe, Asia and North America. With these investments exceeding billions of euros, there is strong incentive to extend the applicability of such Big-Science infrastructure and pursue new possibilities for laser-based high energy physics. Many of these international laboratories have joined the IZEST collaboration as partners and thus will provide the facilities to carry out future pertinent experimental investigations.