Evaluation of a method for treatment of iron gall ink corrosion on paper

Iron gall ink was the most widely used writing ink for paper from the Middle Ages to the twentieth century. Unfortunately, the ink ingredients contain corrosive transition metal ions and acids that cause severe damage to the paper carrier. New or improved paper conservation methods for iron gall ink stabilization are constantly sought. The aim of the study was evaluation of a recently proposed stabilization treatment, adapted to lower relative humidity, applied to various model and historical paper samples containing iron gall ink. The effect of stabilization treatment on paper samples during artificial thermal aging was followed by the determination of the molecular weight distribution by size exclusion chromatography and colorimetry. Migration of iron and copper compounds from the ink lines was monitored by laser ablation inductively coupled plasma mass spectrometry. The results demonstrate that effective stabilization of iron gall ink-containing paper can be successfully achieved by interleaving with papers impregnated with the antioxidant tetrabutylammonium bromide and alkaline buffer under experimental conditions. Negative side effects of the stabilization treatment, such as migration of iron or copper ions from the ink lines and changes of color after the treatment and after accelerated thermal degradation, were limited, proving that the proposed stabilization treatment can be considered for future use by conservators.     

Analytical methods for determination of benzodiazepines. A short review

Benzodiazepines (BDZs) are generally commonly used as anxiolytic and/or hypnotic drugs as a ligand of the GABA_A-benzodiazepine receptor. Moreover, some of benzodiazepines are widely used as an anti-depressive and sedative drugs, and also as anti-epileptic drugs and in some cases can be useful as an adjunct treatment in refractory epilepsies or anti-alcoholic therapy. High-performance liquid chromatography (HPLC) methods, thin-layer chromatography (TLC) methods, gas chromatography (GC) methods, capillary electrophoresis (CE) methods and some of spectrophotometric and spectrofluorometric methods were developed and have been extensively applied to the analysis of number of benzodiazepine derivative drugs (BDZs) providing reliable and accurate results. The available chemical methods for the determination of BDZs in biological materials and pharmaceutical formulations are reviewed in this work.      

A Direct Approach to the cis-1-Octalone System. 2-Carbomethoxy-2-Cyclohexenone as a Dienophile

Under stannic chloride catalysis, 2-carbo-methoxy-2-cyclohexenone (1) was found to undergo Diels-Alder reaction with a variety of dienes to give directly the cis-1-octalone system possessing a functionalized substituent at the angular position.     

Palladium-Catalyzed Diastereoselective Cyclization of the Allylic Precursors. A Concise Synthetic Route to 3-Azabicyclo[3.3.0]Octane and Hydroisoindole Skeletons

A useful variant of palladium-catalyzed 1,2-diastereoselective cyclization of the allylic precursors based on the steric nature of the anion stabilizing groups has been developed. The 1,1,2-trisubstituted cycloalkane products have also been efficiently transformed into the azabicyclic systems.     

On fusible rings

We answer in negative two of questions posed in Ghashghaei and McGovern. We also establish a new characterization of semiprime left Goldie rings by showing that a semiprime ring R is left Goldie iff it is regular left fusible and has finite left Goldie dimension.     

Toxicological evaluation of exposed SPMD membranes

This article is focused on bioassay evaluation of exposed SPMDs. Toxicity testing of SPMD extract is a suitable complementary parameter to chemical analysis. Vtox as an integrative parameter describing toxic properties of extract from membrane and thus a level of contamination of assessed ambient is presented here. Two examples of practical use of Vtox is demonstrated: a course of toxicity throw wastewater treatment plant with industrial inlets and increase of toxicity in surface water body caused by leakages of POPs from industrial plant.     

Measurement of work function changes as a research method for structural phase transitions in adsorbate islands: Cu/Mo(011)

The investigation of work function changes due to temperature changes for copper sub-monolayers adsorbed on the Mo(011) face enables one to observe the structural transition in condensed layers. The interaction energy between adsorbed atoms is determined.     

Long periodic shadowing

A general theorem for establishing the existence of a true periodic orbit near a numerically computed pseudoperiodic orbit of an autonomous system of ordinary differential equations is presented. For practical applications, a Newton method is devised to compute appropriate pseudoperiodic orbits. Then numerical considerations for checking the hypotheses of the theorem in terms of quantities which can be computed directly from the pseudoperiodic orbit and the vector field are addressed. Finally, a numerical method for estimating the Lyapunov exponents of the true periodic orbit is given. The theory and computations are designed to be applicable for unstable periodic orbits with long periods. The existence of several such periodic orbits of the Lorenz equations is exhibited. This revised version was published online in June 2006 with corrections to the Cover Date.     

Applications of k-covers

We investigate a role of k-covers in selection principles theory. Some results about relationships between Ramsey theory and game theory and selection principles that involve k-covers are also given.