On oxidative degradation of parchment and its non-destructive characterisation and dating

Historic parchment is an extremely complex material, not only due to the various methods of production used and various past environmental histories of objects, but also due to its inhomogeneous structure. Many traditional methods of characterisation are empirical, but useful since they have gained recognition by the end-users. In this paper, we investigated the shrinkage temperature of collagen and the influence of lipids contained in parchment on the measurements. While the content of lipids does not seem to significantly affect shrinkage temperature measurements themselves, it strongly affects the decrease of shrinkage temperature of collagen during degradation, and thus its thermomechanical properties. This confirms the high importance of lipid peroxidation during degradation of parchment.     

Effect of reagents mixing on the thermal behavior of sol-gel precursors for silica-based nanocomposite thin films

The paper presents, based on TG-DTG-DSC data, some results of the thermal decomposition of some complex sol-gel precursors used for the deposition of mesoporous ZnO/SiO₂ nanocomposite thin films for gas sensing applications. The effect chemical composition of the sol and reagents mixing during the sol preparation is discussed. The chemical nature of ZnO source (zinc acetate solid salt, zinc acetate alcoholic solution or ZnO nanopowder) used for the sol preparation significantly affects the thermal decomposition of complex precursor and the microstructure and properties of the nanocomposite thin films.     

Analysis of sludge extracts by high resolution GC with selective detectors

Combination of various GC detectors by using a Varian effluent splitter with glass capillary columns has been found to be a rapid procedure for profiling organics extracted from sludges and river sediments. The selectivity and the increased sensitivity of the thermionic nitrogen-phosphorus detector (TSD), the electron capture detector (ECD), and the flame photometric detector (FPD) over the flame ionization detectors (FID) or mass spectrometers allow the detection of compounds present at trace levels without need for extensive sample cleanup. Furthermore, the combination of two selective detectors may supplement the information with regard to the chemical functionalities required for structure elucidation.     

Demonstration of Allium sativum Extract Inhibitory Effect on Biodeteriogenic Microbial Strain Growth,Biofilm Development,and Enzymatic and Organic Acid Production

To the best of our knowledge, this is the first study demonstrating the efficiency of Allium sativum hydro-alcoholic extract (ASE) againstFigure growth, biofilm development, and soluble factor production of more than 200 biodeteriogenic microbial strains isolated from cultural heritage objects and buildings. The plant extract composition and antioxidant activities were determined spectrophotometrically and by HPLC–MS. The bioevaluation consisted of the qualitative (adapted diffusion method) and the quantitative evaluation of the inhibitory effect on planktonic growth (microdilution method), biofilm formation (violet crystal microtiter method), and production of microbial enzymes and organic acids. The garlic extract efficiency was correlated with microbial strain taxonomy and isolation source (the fungal strains isolated from paintings and paper and bacteria from wood, paper, and textiles were the most susceptible). The garlic extract contained thiosulfinate (307.66 ± 0.043 µM/g), flavonoids (64.33 ± 7.69 µg QE/g), and polyphenols (0.95 ± 0.011 mg GAE/g) as major compounds and demonstrated the highest efficiency against the Aspergillus versicolor (MIC 3.12–6.25 mg/mL), A. ochraceus (MIC: 3.12 mg/mL), Penicillium expansum (MIC 6.25–12.5 mg/mL), and A. niger (MIC 3.12–50 mg/mL) strains. The extract inhibited the adherence capacity (IIBG% 95.08–44.62%) and the production of cellulase, organic acids, and esterase. This eco-friendly solution shows promising potential for the conservation and safeguarding of tangible cultural heritage, successfully combating the biodeteriogenic microorganisms without undesirable side effects for the natural ecosystems.     

Supercritical fluid extraction of oxindole alkaloids from Uncaria tormentosa

Supercritical fluid extraction of oxindole alkaloids from Uncaria Tormentosa is described. The extraction was performed with supercritical carbon dioxide alone and with supercritical carbon dioxide modified with 10% metanol, and the extracts were analyzed by GC/MS and HPLC/MS.     

Internal conversion in inner shells of atomic ions and relativistic ionic potentials

Internal conversion coefficients for inner shells of atomic ions of Sn are calculated for various degrees of ionization and compared with neutral atom predictions. The relativistic version of an analytic perturbation theory is used to include screening effects.     

Rayleigh scattering fromn=3 states of hydrogenlike atoms

An exact analytic evaluation of the Kramers-Heisenberg matrix elements for Rayleigh scattering fromn=3 states of hydrogenlike atoms is performed in the nonrelativistic dipole approximation, using the Green's function method. The results are given separately for each subshell. The possibility of 3s?3d transitions is also considered. The dependence on the photon energy is contained in six invariant amplitudes. The formulas needed for the evaluation of the various cross sections are presented. The numerical results are contained in tables from which partial and total cross sections can be easily built, covering the energy range from zero up to 20 times theK threshold energy. In the vicinity of Balmerα frequency the cross section is large and comparable with that for excitedn=2 states, confirming an earlier hypothesis of Röhr. At other energies the cross sections forn=2 andn=3 states are comparable, too. The results should be useful in plasma diagnostics.     

Silver sorption on acrylic copolymers functionalized with amines. Equilibrium and kinetic studies

The sorption capacity of three weak base ion exchangers based on acrylic copolymers functionalized with ethylenediamine, triethylenetetramine and N, N- dimethylamino propylamine for Ag(I) ions was evaluated. Adsorption experiments were carried out by batch method. The effect of pH, crosslinking degree of copolymers, amount of sorbent, initial ion concentration, contact time and temperature was studied. The parameters which characterize the retention process were estimated using Langmuir and Freundlich isotherm models, the best fitting being for the first model. Kinetic data were fitted to pseudo-first order, pseudo-second order and intraparticle diffusion models. Experimental data were in good agreement with the pseudo second order.      

On-line microwave-induced helium plasma atomic emission detection for capillary zone electrophoresis

We report a feasibility study on using a microwave-induced helium plasma atomic emission detector (MIP-AED) as an on-line detector in capillary zone electrophoresis (CZE). To couple CZE to MIP-AED, we used an ion exchange membrane capillary to connect the separation capillary to the interfacing capillary. The outlet end of the interfacing capillary was placed directly in the discharge tube of the MIP-AED system. The electroosmotic flow generated in the separation capillary carried the analytes and the electrolyte buffer solution through the interfacing capillary into the MIP-AED discharge tube where the analytes were detected. The performance of the CZE/MIP-AED system was evaluated with trimethyltin chloride, dimethyltin dichloride, n-propanol, and 2-butanone. The preliminary results indicate that the MIP-AED can be used in CZE to provide element-specific detection for target analytes.