Measurement of the high-energy electron and positron spectrum in the PAMELA experiment

The PAMELA magnetic spectrometer onboard the Resurs DK1 satellite no. 1 was put into (Earth) orbit on June 15, 2006; measurements continue at the present time. The scientific objective of the spectrometer is the study of antiproton, proton, positron, electron and light nucleus fluxes in cosmic rays. In this paper, we present the technique for measuring electron and positron spectra in the energy range from 20 to 800 GeV.     

Immobilization of Heparin and Highly-Sulphated Hyaluronic Acid onto Plasma-Treated Polyethylene

Heparin and highly-sulphated hyaluronic acid have been successfully immobilized onto plasma-processed polyethylene via a diamine polyethyleneglycol (PEG) spacer molecule. Two different plasma-processes have been utilized, i.e. a treatment and a deposition process, for providing polyethylene surface with the COOH groups necessary for the immobilization reactions. XPS integrated with derivatization procedures, ATR-FTIR and Water Contact Angle measurements have been carried out for characterizing each modification step: 1) the plasma-process, 2) the immobilization of the spacer molecule and 3) the immobilization of the biomolecules. The thrombin time of the modified surfaces has been measured, and their platelet activation characteristics evaluated. The results indicate a certain nonthrombogenic character of the biomolecule-immobilized polyethylene samples.     

Photo‐Induced Ruthenium‐Catalyzed C−H Arylations at Ambient Temperature

Ambient temperature ruthenium‐catalyzed C?H arylations were accomplished by visible light without additional photocatalysts. The robustness of the ruthenium‐catalyzed C?H functionalization protocol was reflected by a broad range of sensitive functional groups and synthetically useful pyrazoles, triazoles and sensitive nucleosides and nucleotides, as well as multifold C?H functionalizations. Biscyclometalated ruthenium complexes were identified as the key intermediates in the photoredox ruthenium catalysis by detailed computational and experimental mechanistic analysis. Calculations suggested that the in situ formed photoactive ruthenium species preferably underwent an inner‐sphere electron transfer.     

Domino synthesis of 1,3,5-trisubstituted hydantoins: a DFT study

The mechanism of the reaction between carbodiimides and activated α,β-unsaturated carboxylic acids yielding fully substituted hydantoins and variable amounts of N-acyl urea by-products was studied using density functional theory calculations. Two alternative pathways featuring N-acyl ureas and imino-oxazolidinones as intermediates for the formation of the hydantoin product were taken into account. The results obtained using two different computational models indicate that the overall barriers are similar for the two pathways considered. In all cases, inclusion of a second molecule of carboxylic acid was required to mediate tautomerizations and rearrangement steps. The calculations successfully reproduce the experimentally observed regioselectivity with respect to both N-acyl urea and hydantoin products.     

A crystallinity study of dental tissues and tartar by infrared spectroscopy

In this paper we report a study of an important property of biomineralized phases, crystallinity, on the basis of previous results for synthetic apatite. Crystallinity is not only important for understanding biomineralization, it is also related to the maturation and mechanisms of growth of calcium phosphates in biological surroundings. We studied two kinds of sample, teeth as an example of biomineralized tissues and dental calculi (adhering) as an example of mineralization without participation of biological agents, except possibly bacteria. The investigation focused on study of ν(1)-ν(3) infrared absorption bands of PO(4)(3-) phosphates. We used ATR (attenuated total reflection) analysis to examine human dental tissues and tartar on several samples. The results confirm for the first time previous assumptions about the growth and maturation of dental calculi, i.e., crystallinity progresses from regions of high crystallinity to regions of lower crystallinity, and, in addition, its quantification with spatial resolution in the sample. A gradual pattern was observed in dental calculus. Another result from this study was that cementum and dentine had similar crystallinity, despite their different biological and mechanical functions.     

Functional histology of glioma vasculature by FTIR imaging

Fourier-transform infrared (FTIR) imaging has been used to investigate brain tumor angiogenesis using a mice solid tumor model and bare-gold (∅ 25 nm) or BaSO₄ (∅ 500 nm) nanoparticles (NP) injected into blood vasculature. FTIR images of 20-μm-thick tissue sections were used for chemical histology of healthy and tumor areas. Distribution of BaSO₄-NP (using the 1,218–1,159 cm⁻¹ spectral interval) revealed clearly all details of blood vasculature with morphological abnormalities of tumor capillaries, while Au-NP (using the 1,046–1,002 cm⁻¹ spectral interval) revealed also diffusion properties of leaky blood vessels. Diffusion of Au-NP out of vascular space reached 64 ± 29 μm, showing the fenestration of “leaky” tumor blood vessels, which should allow small NP (<100 nm, as for Au-NP) to diffuse almost freely, while large NP should not (as for BaSO₄-NP in this study). Therefore, we propose to develop FTIR imaging as a convenient tool for functional molecular histology imaging of brain tumor vasculature, both for identifying blood capillaries and for determining the extravascular diffusion space offered by vessel fenestration.     

The role of chemometrics in single and sequential extraction assays: a review: part I. Extraction procedures, uni- and bivariate techniques and multivariate variable reduction techniques for pattern recognition

Element mobility and availability in natural solid matrices can be studied with single and sequential extraction procedures; such procedures provide reliable and useful information only if the experiments are correctly planned and executed and the results are properly interpreted. Chemometrics can be a valuable tool for these aims, especially taking into account the large amounts of data generated with extraction essays and the complexity of the processes under investigation. This review deals with the application of chemometrics in research studies involving single and sequential extractions on soils or sediments, for several purposes: the development and optimization of the extraction conditions, the calculation of element fractionation, the visual illustration of the experimental results, the acquisition of different areas of information, including relationships among variables, similarities and differences among samples, causes of the observed behaviour (e.g. source identification), risk assessment, models and predictions of future events. In Part I of the review, following an overview on extraction procedures, the applications of univariate and bivariate chemometric methods are reported; then the principles of multivariate techniques for pattern recognition based on variable reduction, their applications and the main findings obtained are addressed.     

Boundary Value Problems for Highly Nonlinear Inclusions Governed by Non-surjective Φ-Laplacians

Combining fixed point theorems with the method of lower and upper solutions, we get the existence of solutions to the following nonlinear differential inclusion:

$ (D(x(t))\Phi(x'(t)))' \in G(t,x(t),x'(t)) \ \ \mbox{a.e. } t\in I=[0,T], $

satisfying various nonlinear boundary conditions, covering Dirichlet, Neumann and periodic problems. Here Φ is a non-surjective homeomorphism and D is a generic positive continuous function.