This work reports the use of benzophenone, a very
    well characterized probe, to study new hosts (i.e., modified
    celluloses grafted with alkyl chains bearing 12 carbon atoms)
    by surface esterification. Laser-induced room temperature
    luminescence of air-equilibrated or argon-purged solid
    powdered samples of benzophenone adsorbed onto the two
    modified celluloses, which will be named C12-1500 and
    C12-1700, revealed the existence of a vibrationally structured
    phosphorescence emission of benzophenone in the case where
    ethanol was used for sample preparation, while a nonstructured
    emission of benzophenone exists when water was used instead of
    ethanol. The decay times of the benzophenone emission vary
    greatly with the solvent used for sample preparation and do
    not change with the alkylation degree in the range of
    1500&#x2013;1700 micromoles of alkyl chains per gram of cellulose.
    When water was used as a solvent for sample preparation, the
    shortest lifetime for the benzophenone emission was observed;
    this result is similar to the case of benzophenone adsorbed
    onto the &#x201C;normal&#x201D; microcrystalline cellulose
    surface, with this latter case previously reported by Vieira
    Ferreira et al. in 1995. This is due to the more efficient
    hydrogen abstraction reaction from the glycoside rings of
    cellulose when compared with hydrogen abstraction from the
    alkyl chains of the modified celluloses. Triplet-triplet
    transient absorption of benzophenone was obtained in both
    cases and is the predominant absorption immediately after
    laser pulse, while benzophenone ketyl radical formation occurs
    in a microsecond time scale both for normal and modified
    celluloses.

L. F. Vieira Ferreira

A. I. Costa

I. Ferreira Machado

T. J. F. Branco

S. Boufi

M. Rei-Vilar

A. M. Botelho do Rego

Surface Photochemistry: Benzophenone as a Probe for the Study of Modified Cellulose Fibres

Dyed natural rubber (NR) and styrene butadiene rubber (SBR), designed for outdoor applications, were exposed to an accelerated artificial aging in xenon light. The aging results in the deterioration of the exposed surface material properties. The ability of dyed polymers to withstand prolonged sunlight exposure without fading or undergoing any physical deterioration is largely determined not only by the photochemical characteristics of the absorbing dyestuff itself but also by the polymer structure and fillers. Results obtained by laser mass spectrometry, UV-visible spectroscopy, and environmental scanning electron microscopy indicate that dyed filled NR and SBR samples behave differently during the photo-oxidation. The fading of the dyed polymers was found to be promoted in the NR sample. This can be correlated with LDI-FTICRMS results, which show the absence of [M-H]&#x2212; orange pigment pseudomolecular ion and also its fragment ions after aging. This is confirmed by both EDX and UV/Vis spectroscopy. EDX analysis indicates a concentration of chlorine atoms, which can be considered as a marker of orange pigment or its degradation products, only at the surface of SBR flooring after aging. Reactivity of radicals formed during flooring aging has been studied and seems to greatly affect the behavior of such organic pigments.

Junien  Exposito

Claude  Becker

David  Ruch

Fr&#233;d&#233;ric  Aubriet

Study of Polymer Material Aging by Laser Mass Spectrometry, UV-Visible Spectroscopy, and Environmental Scanning Electron Microscopy

High-level ab-initio equation-of-motion coupled-cluster methods with singles, doubles, and noniterative triples are used, in conjunction with the combined quantum mechanical molecular mechanics approach, to investigate the structure of low-lying
excited states of the guanine base in DNA and solvated environments. Our results indicate that while the excitation energy of the first excited state is barely changed compared to its gas-phase counterpart, the excitation energy of the second excited
state is blue-shifted by 0.24&#x2009;eV.

Karol Kowalski

Marat Valiev

Structure of Low-Lying Excited States of Guanine in DNA and Solution: Combined Molecular Mechanics and High-Level Coupled Cluster Studies

Psoralen interaction with two models of DNA was investigated using molecular mechanics and molecular dynamics methods. Calculated energies of minor groove binding and intercalation were compared in order to define a preferred binding mode for the ligand. We found that both binding modes are possible, explaining the low efficiency for monoadduct formation from intercalated ligands. A comparison between the interaction energy for intercalation between different base pairs suggests that the observed sequence selectivity is due to favorable intercalation in <mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>5</mml:mn><mml:mo>&#x2032;</mml:mo></mml:math>-TpA in <mml:math id="E2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mtext>AT</mml:mtext></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mtext>n</mml:mtext></mml:msub></mml:math> sequences.

Patricia Saenz-M&#xE9;ndez

Rita C. Guedes

Daniel J. V. A. dos Santos

Leif A. Eriksson

Theoretical Study of Sequence Selectivity and Preferred Binding Mode of Psoralen with DNA

The kinetics of paracetamol oxidation are first order each in [paracetamol] and [<mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>HClO</mml:mtext></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>]. The kinetic study shows that the oxidation proceeds in two steps. The effects of anionic micelles of sodiumdodecyl sulphate (SDS) and complexing agents (ethylenediammine tetraacetic acid (EDTA) and 2,<mml:math id="E2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mn>2</mml:mn><mml:mo>&#x2032;</mml:mo></mml:msup></mml:math>-bipyridyl (bpy)) were also studied. Fast kinetic spectrophotometric method has been described for the determination of paracetamol. The method is based on the catalytic effect of manganese(II) on the oxidation of paracetamol by chromium(VI) in the presence of <mml:math id="E3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>HClO</mml:mtext><mml:mn>4</mml:mn></mml:msub></mml:math> (= 0.23 mol d<mml:math id="E4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mtext>m</mml:mtext><mml:mrow><mml:mo>&#x2212;</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:math>). Optimum reaction time is 4 to 6 minutes at a temperature of <mml:math id="E5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mn>30</mml:mn><mml:mo>&#x2218;</mml:mo></mml:msup></mml:math>C. The addition of manganese(II) ions largely decreased the absorbance of chromium(VI) at 350&#x2009;nm. This reaction can be utilized for the determination of paracetamol in drugs.

Mohammed Ilyas

Maqsood Ahmad Malik

Syed Misbah Zahoor Andrabi

Zaheer Khan

Kinetics and Mechanism of Paracetamol Oxidation by Chromium(VI) in Absence and Presence of Manganese(II) and Sodiumdodecyl Sulphate

Analysis of phase transformation processes observed in hydrogen absorbing materials
(pure metals, alloys, or compounds) is still a matter of active research. Using pneumato-chemical
impedance spectroscopy (PIS), it is now possible to analyze the mechanism of hydriding
reactions induced by the gas phase. Experimental impedance diagrams, measured on activated
<mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>LaNi</mml:mtext></mml:mrow><mml:mn>5</mml:mn></mml:msub></mml:mrow></mml:math> in single- and two-phase domains, are reported in this paper. It is shown that their shape is
mostly affected by the slope of the isotherm at the measurement point. By considering the details
of the multistep reaction paths involved in the hydriding reaction, model impedance equations
have been derived for single- and two-phase domains, and fitted to experimental impedance
diagrams. The possibility of separately measuring surface and phase transformation resistances,
hydrogen diffusion coefficient, and hydrogen solubility in each composition domain is discussed.

P. Millet

C. Decaux

R. Ngameni

M. Guymont

Fourier-Domain Analysis of Hydriding Kinetics Using Pneumato-Chemical Impedance Spectroscopy

Quartz crystal microbalance (QCM) was used to investigate the adsorption of acid-oxidized single-walled carbon nanotubes (Ox-SWNTs) and poly(vinyl pyrrolidone), PVP. It was found for the first time that Ox-SWNTs adsorbed onto the QCM electrode can be effectively replaced by PVP chains in an aqueous solution. This replacement process was also investigated by atomic force miscroscopic (AFM) imaging, which shows good agreement with the QCM measurements. This study provides powerful tools for fundamental investigation of polymer-nanotube interactions and for controlled design/fabrication of functional polymer-nanotube surfaces for potential applications.

Wei Chen

Xiaojun Li

Liming Dai

Surface Adsorption and Replacement of Acid-Oxidized Single-Walled Carbon Nanotubes and Poly(vinyl pyrrolidone) Chains

We report on unique high-volume low-dimensional <mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>V</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>5</mml:mn></mml:msub></mml:math>-based turbostratic nanostructures, prepared using sol-gel synthetic methods from <mml:math id="E2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>V</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>5</mml:mn></mml:msub><mml:mo>&#x22C5;</mml:mo><mml:mi>n</mml:mi><mml:msub><mml:mtext>H</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mtext>O</mml:mtext></mml:math> xerogels. Electrochemical intercalation of <mml:math id="E3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mtext>Li</mml:mtext><mml:mo>+</mml:mo></mml:msup></mml:math> to form <mml:math id="E4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Li</mml:mtext><mml:mrow><mml:mn>0.65</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mtext>V</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>5</mml:mn></mml:msub></mml:math> resulted in a maximum measured charge capacity of 1225&#x2009;mAh&#x2009;<mml:math id="E5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mtext>g</mml:mtext><mml:mrow><mml:mo>&#x2212;</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:math> as the <mml:math id="E6" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x03B2;</mml:mi></mml:math>-<mml:math id="E7" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Li</mml:mtext></mml:mrow><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mtext>V</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>5</mml:mn></mml:msub></mml:mrow></mml:math> phase. Conductivities of the 
order of 10&#x2212;3&#x2009;S&#x2009;cm&#x2212;1 were found on compressed-nanotube parallelepipedal samples, which exhibit an anisotropy factor of 70 at room temperature by preferential alignment of the nanotubes. The improved electrochemical properties observed in novel vanadium oxide nanostructured arrays are attributed to the increased volumetric density for ion intercalation, shorter diffusion paths to the intercalation sites, and a high degree of crystallinity of
the individual nanotubular host structures.

C. O&#x27;Dwyer

V. Lavayen

M. A. Santa Ana

E. Benavente

G. Gonz&#xE1;lez

C. M. Sotomayor Torres

Anisotropic Vanadium Oxide Nanostructured Host Matrices for Lithium Ion Intercalation

The possibility of recording physical changes in aqueos solutions caused by a unique field generated by the Teslar chip (TC) inside a quartz wristwatch has been studied using holographic interferometry. We show that the refraction index of degassed pure distilled water and aqueous solutions of L-tyrosine and b-alanine affected by the TC does not change during the first 10 minutes of influence. In contrast, a 1&#37; aqueous solution of plasma extracted from the blood of a patient with heart vascular disease changes the refractive index when affected by the TC. The characteristic time of reaction is about <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mn>2</mml:mn></mml:msup></mml:mrow></mml:math>&#x2009;seconds. Based on our prior research experience, we state that the response of the system studied to the TC&#39;s field is similar to that stipulated by the action of a constant magnetic field with the intensity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>1.1</mml:mn><mml:mo>&#x00D7;</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>&#x2212;</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>&#x2009;T. Nevertheless, 
our team have unambiguously proved that the 
TC generates the inerton field, 
which is associated with a substructure of 
the matter waves (and, therefore, it does not relate to 
the electromagnetic nature). 
We could unambiguously prove that the TC generates the inerton field.

E.  Andreev

G.  Dovbeshko

V.  Krasnoholovets

The Study of Influence of the Teslar Technology on Aqueous  Solution of Some Biomolecules

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