Ring‐opening metathesis polymerization of fatty acid derived monomers

The ring‐opening metathesis polymerization (ROMP) of fatty acid functionalized norbornenes was explored in the presence of dichloro[1,3‐bis(2,4,6‐trimethylphenyl)‐2‐imidazolidinylidene](benzylidene)bis(3‐bromopyridine)ruthenium(II) ( C3 ) at room temperature. The investigated monomers were derived from fatty acids with different chain lengths (C₆, C₈, C₁₀, C₁₂, C₁₄, C₁₆, and C₁₈) and can therefore contribute to the development of more sustainable, bio‐based polymeric materials. The polymerizations initiated by C3 proceeded in a living fashion with good initiation efficiency, and thus the synthesis of well‐defined polymers with narrow polydispersities was accomplished. All prepared polymers were fully characterized (GPC, DSC, TGA, NMR) and the results of these investigations are discussed within this contribution. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Does Maternal Treatment with Zidovudine Affect Changes in Mandibles of Newborns? Laser Induced Fluorescence Study

The influence of antiretroviral drug zidovudine treatment during pregnancy on mandible development in newborn rats was studied. The fluorescence of mandibles from 7-, 14- and 28-days old individuals was measured by means of fiber-optical fluorescence analyzer with 407 nm laser excitation. Obtained results revealed disturbing effect of maternal zidovudine administration on mandible fluorescence intensity which should decrease with bone development. Small changes in fluorescence of porphyrin forms are maintaining in the first month of newborns life while the changes observed in 440–585 nm range disappear.     

Simultaneous pH and Temperature Measurements Using Pyranine as a Molecular Probe

Steep variations in concentration and temperature frequently occur in small fluid compartments such as those found in cells or microfluidic devices. A quantitative characterization of concentration and temperature gradients is therefore required before these systems can be fully understood. Although different spatially resolved fluorescence methods have been developed to measure either the temperature or the concentration of ions such as proton or calcium, often concentration measurements depend on temperature and vice versa. Here, we describe a method allowing simultaneous measurement of pH and temperature. This method is based on the detection of the blinking of the fluorescent pH indicator pyranine, a process due to its alternating between a basic form and an acidic form. Fluorescence correlation spectroscopy allows measuring both the protonation and deprotonation rates of pyranine, and each pair of rates can be uniquely related to a pair of pH and temperature values. We show, however, that the relationship between rates, pH and temperature, is very sensitive to the presence of other acid-base molecules in solution. We also show that it is influenced by the overall ionic strength of the solution, in a manner that depends on buffer composition.     

On the Bergman Theory for Solenoidal and Irrotational Vector Fields. II. Conformal Covariance and Invariance of the Main Objects

This is a continuation of our work (González-Cervantes et al. in On the Bergman theory for solenoidal and irrotational vector fields. I. General theory. Operator theory: advances and applications. Birkhauser, accepted) where for solenoidal and irrotational vector fields theory as well as for the Moisil–Théodoresco quaternionic analysis we introduced the notions of the Bergman space and the Bergman reproducing kernel and studied their main properties. In particular, we described the behavior of the Bergman theory for a given domain whenever the domain is transformed by a conformal map. The formulas obtained hint that the corresponding objects (spaces, operators, etc.) can be characterized as conformally covariant or invariant, and in the present paper we construct a series of categories and functors which allow us to give such characterizations in precise terms.     

Optically implemented broadband blueshift switch in the terahertz regime

We experimentally demonstrate, for the first time, an optically implemented blueshift tunable metamaterial in the terahertz (THz) regime. The design implies two potential resonance states, and the photoconductive semiconductor (silicon) settled in the critical region plays the role of intermediary for switching the resonator from mode 1 to mode 2. The observed tuning range of the fabricated device is as high as 26% (from 0.76 THz to 0.96 THz) through optical control to silicon. The realization of broadband blueshift tunable metamaterial offers opportunities for achieving switchable metamaterials with simultaneous redshift and blueshift tunability and cascade tunable devices. Our experimental approach is compatible with semiconductor technologies and can be used for other applications in the THz regime.     

Low-Energy Kaon�CNucleon/Nuclei Interaction Studies at DA��NE (SIDDHARTA and AMADEUS Experiments)

The DA??NE electron?Cpositron collider at the Laboratori Nazionali di Frascati of INFN has made available a unique quality low-energy negative kaons ??beam??. The SIDDHARTA experiment used this beam to perform unprecedented precision measurements on kaonic atoms, while the AMADEUS experiment plans to perform in the coming years precision measurements on kaon?Cnuclei interactions at low-energies, in particular to study the kaonic nuclei. The two experiments are briefly presented in this paper.     

Dipolar and quadrupolar detection using an FT-ICR MS setup at the MPIK Heidelberg

Dipolar and single-phase two-electrode quadrupolar detection schemes have been investigated at a Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) setup built for the KATRIN experiment at the Max-Planck-Institute for Nuclear Physics (MPIK) in Heidelberg. We present first experimental results of ⁷Li^?+? signals from a cylindrical Penning trap configuration for both detection schemes. While the prominent signal of the conventional dipolar detection scheme marks the reduced cyclotron frequency, the main signal for the quadrupolar detection appears at the sum of the reduced cyclotron frequency and the magnetron frequency. For ideal trapping fields, this sum frequency equals the ion cyclotron frequency ?? _c ?=?qB/(2??m). Sidebands due to the combined motions of the cyclotron mode and magnetron mode are observed by quadrupolar detection which allows the determination of the respective combinations of eigenfrequencies.     

Study of ethylic Babassu biodiesel properties at low temperatures

Nowadays the growing fuel deficit requires the development of alternative fuel sources. Biodiesel is a good substitute to the conventional diesel because it is quite similar to the fossil fuel in its main characteristics. However, there are some obstacles, as the properties of cold-flow, to the development of a more useful alternative fuel. In this work we use the X-ray diffraction and differential calorimetry scanning to study low temperature properties of ethylic Babassu biodiesel. Our results show that the nucleation of crystals starts below ?8 °C and the crystallization temperature does not change significantly when the sample was submitted to a winterization process. The higher concentrations of ethyl esters from saturated fat acid are probably responsible for this characteristic. The X-ray diffraction, combined with DSC measurements, was efficiently employed in the characterization of cold-flow biodiesel properties, showing to be very helpful techniques.     

Activation and structural and adsorption features of activated carbons with highly developed micro-, meso- and macroporosity

Three sets of activated carbons (ACs) were prepared with the same precursor but activated differently (by CO₂ or water vapour) with various burn-off levels. The ACs demonstrate increased deviation of the pore shape from the slitshaped model with increasing burn-off and contributions of pores of different sizes depending on the activation type. Significant re-arrangement of adsorption complexes, especially of the Van der Waals type characteristic for nonpolar or weakly polar adsorbates (H₂, CH₄, CH₂Cl₂, CHCl₃), occurs in both micropores and mesopores of ACs with decreasing temperature. The behaviour of their mixtures with water and DMSO can strongly differ from that of individual adsorbates.