129I levels in soils from Ukraine and Slovenia in the last decade

¹²⁹I is important as an environmental tracer of the biogeochemical cycling of iodine and of the dissemination of nuclear pollution, because anthropogenic ¹²⁹I has been released from only few point sources and with its short mixing time its distribution therefore reveals the movement of ¹²⁹I in the environment. A radiochemical neutron activation analysis method was developed to measure the concentration of ¹²⁹I in soil samples. A procedure to pre-concentrate iodine from up to 150?g of soil was developed and validated using IAEA standard reference material IAEA-375 (Chernobyl soil). The method was applied to determine ¹²⁹I/¹²⁷I isotopic ratios as well as ¹²⁹I and ¹²⁷I concentrations in soils from several locations in Ukraine collected in 2006, 1996, 1993 and 1989, and from Slovenia, collected at various places in 2009 and 2006. The ¹²⁷I concentrations in surface soils from Ukraine were in the range 2.3–23.1?µg?g^?1 and for ¹²⁹I (11.1–245.7)?·?10^?8?µg?g^?1 dry matter with the highest value of 1.47?·?10^?3?µg?g^?1 found in a soil sample collected in Yaniv, Ukraine in July 1993. In soil samples from Slovenia ¹²⁷I concentrations ranged 0.73–130?µg?g^?1 and ¹²⁹I (8.0–245.7)?·?10^?8?µg?g^?1. The ¹²⁹I/¹²⁷I isotopic ratios of surface soils from Ukraine were in the range of the order of 10^?9–10^?5 and of 10^?10–10^?8 for soils from Slovenia. The highest isotopic ratio 13.6?·?10^?5 was found in a soil sample collected in Yaniv, Ukraine in July 1993.     

Transformation of 5-Oxo Substituted Fused Pyran-2-ones. Lactam Versus Hydrazone Formation

6, 7-Dihydrocyclopenta[b]pyran-2, 5-dione 1 was converted with hydrazines to fused pyridine-2(1H)-ones of type a. In contrast, 2H-1-benzopyran-2, 5-diones 2–4 gave under the same reaction conditions 5-hydrazonobenzopyrans of type b. Calculated heats of formation matched experimental findings.     

In situ photoexcitation of silver-doped titania nanopowders for activity against bacteria and yeasts

Photocatalytic and in situ microbial activity of the amorphous and annealed states of Ag-doped and un-doped titania were examined. Studies on their structure, morphology, composition, and the photo-absorption characteristics of these materials were performed. These results were correlated with the photocatalytic and microbial activity against methicillin resistant Staphylococcus aureus K324 (MRSA), methicillin susceptible S. aureus ATCC 25923 (MSSA), Escherichia coli PA 170, and yeasts Candida albicans ATCC 90028. The annealed powders containing anatase form of titania exhibited relatively higher photocatalytic activity,corresponding to activity against MRSA,when exposed to UV-A radiation. In comparison, amorphous powders exhibited low photoactivity and showed poor antibacterial performance against MRSA under UV-A exposure. Doping of amorphous titania with Ag resulted in an anti-MRSA effect without exposure to UV radiation. In the Ag-doped crystalline anatase samples, the size of Ag primary nanocrystallites increased, which led to the decrease in the surface concentration of Ag and detriment anti-MRSA activity.     

Discrimination Between Peptide O-Sulfo- and O-Phosphotyrosine Residues by Negative Ion Mode Electrospray Tandem Mass Spectrometry

Unambiguous differentiation between isobaric sulfated and phosphorylated tyrosine residues (sTyr and pTyr) of proteins by mass spectrometry is challenging, even using high resolution mass spectrometers. Here we show that upon negative ion mode collision-induced dissociation (CID), pTyr- and sTyr-containing peptides exhibit entirely different modification-specific fragmentation patterns leading to a rapid discrimination between the isobaric covalent modifications using the tandem mass spectral data. This study reveals that the ratio between the relative abundances of [M-H-80](-) and [M-H-98](-) fragment ions in ion-trap CID and higher energy collision dissociation (HCD) spectra of singly deprotonated +80 Da Tyr-peptides can be used as a reliable indication of the Tyr modification group nature. For multiply deprotonated +80 Da Tyr-peptides, CID spectra of sTyr- and pTyr-containing sequences can be readily distinguished based on the presence/absence of the [M-nH-79]((n-1)-) and [M-nH-79-NL]((n-1)-) (n=2, 3) fragment ions (NL=neutral loss).     

Virtual gonio-spectrophotometer for validation of BRDF designs

Measurement of the appearance of an object consists of a group of measurements to characterize the color and surface finish of the object. This group of measurements involves the spectral energy distribution of propagated light measured in terms of reflectance and transmittance, and the spatial energy distribution of that light measured in terms of the bidirectional reflectance distribution function (BRDF). In this article we present the virtual gonio-spectrophotometer, a device that measures flux (power) as a function of illumination and observation. Virtual gonio-spectrophotometer measurements allow the determination of the scattering profile of specimens that can be used to verify the physical characteristics of the computer model used to simulate the scattering profile. Among the characteristics that we verify is the energy conservation of the computer model. A virtual gonio-spectrophotometer is utilized to find the correspondence between industrial measurements obtained from gloss meters and the parameters of a computer reflectance model.     

Structural properties of effective potential model by liquid state theories

This paper investigates the structural properties of a model fluid dictated by an effective inter-particle oscillatory potential by grand canonical ensemble Monte Carlo (GCEMC) simulation and classical liquid state theories.The chosen oscillatory potential incorporates basic interaction terms used in modeling of various complex fluids which is composed of mesoscopic particles dispersed in a solvent bath,the studied structural properties include radial distribution function in bulk and inhomogeneous density distribution profile due to influence of several external fields.The GCEMC results are employed to test the validity of two recently proposed theoretical approaches in the field of atomic fluids.One is an Ornstein-Zernike integral equation theory approach;the other is a third order + second order perturbation density functional theory.Satisfactory agreement between the GCEMC simulation and the pure theories fully indicates the ready adaptability of the atomic fluid theories to effective model potentials in complex fluids,and classifies the proposed theoretical approaches as convenient tools for the investigation of complex fluids under the single component macro-fluid approximation.     

Protein Folding: A Perspective from Theory and Experiment

The mechanism of protein folding (represented schematically below) is one of the most fascinating problems in the field of chemical reactions. This review presents the progess made recently in understanding key elements of this reaction and describes a solution to the often quoted Levinthal Paradox.     

Synthesis and properties of 4,5‐dihydrobenzo[e]imidazo[2,1‐c][1,4,2]diazaphosphinine derivatives

A number of 4,5‐dihydrobenzo[e]imidazo[2,1‐c][1,4,2]diazaphosphinine derivatives were prepared by the direct phosphorylation of 1‐(4‐Chlorophenylcarboxamido)‐2‐(1H‐1‐imidazolyl)‐5‐trifluoromethylbenzene in basic medium with phosphorus(III) bromide and dibromophenylphosphine. The tricyclic compounds 6a, 6b , and 9 having a trivalent phosphorus atom undergo the diazaphosphinine ring opening upon treatment with secondary amines in the presence of sulfur. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:84–92, 2002; DOI 10.1002/hc.10000     

The Last Fortress of Tin's Tyranny – Protodenitration of Nitroalkanes

Protodenitration, a direct reduction of nitroalkanes to corresponding alkanes, already spans two centuries and is enabled by various reagents. This mini-review provides a historical development of the fundamental transformation and highlights the governing position of the Ono-Tanner reaction employing tributyltin hydride. Due to the unchallenged dominance of the toxic tributyltin hydride and environmentally unpopular solvents sharply contrasting with modern ecological trends, the current situation was dubbed “the last fortress of tin's tyranny.”     

Electricity consumption prediction using artificial intelligence

Central European Journal of Operations Research - The measurement of electricity consumption at 15-minute granularity, including for households, is increasingly mandated in the EU and this also...