Predominant Information Quality Scheme for the Essential Amino Acids: An Information‐Theoretical Analysis

In this work we undertake a pioneer information‐theoretical analysis of 18 selected amino acids extracted from a natural protein, bacteriorhodopsin (1C3W). The conformational structures of each amino acid are analyzed by use of various quantum chemistry methodologies at high levels of theory: HF, M062X and CISD(Full). The Shannon entropy, Fisher information and disequilibrium are determined to grasp the spatial spreading features of delocalizability, order and uniformity of the optimized structures. These three entropic measures uniquely characterize all amino acids through a predominant information‐theoretic quality scheme (PIQS), which gathers all chemical families by means of three major spreading features: delocalization, narrowness and uniformity. This scheme recognizes four major chemical families: aliphatic (delocalized), aromatic (delocalized), electro‐attractive (narrowed) and tiny (uniform). All chemical families recognized by the existing energy‐based classifications are embraced by this entropic scheme. Finally, novel chemical patterns are shown in the information planes associated with the PIQS entropic measures.     

Amphiphilic conetworks. IV. Poly(methacrylic acid)‐l‐polyisobutylene and poly(acrylic acid)‐l‐polyisobutylene based hydrogels prepared by two‐step polymer procedure. New pH responsive conetworks

This article describes the synthesis and characterization of new amphiphilic polymer conetworks containing hydrophilic poly(methacrylic acid) (PMAA) or poly(acrylic acid) (PAA) and hydrophobic polyisobutylene (PIB) chains. These conetworks were prepared by a two‐step polymer synthesis. In the first step, a cationic copolymer of isobutylene (IB) and 3‐isopropenyl‐α,α‐dimethylbenzyl isocyanate (IDI) was prepared. The isocyanate groups of the IB–IDI random copolymer were subsequently transformed in situ to methacrylate (MA) groups in reaction with 2‐hydroxyethyl methacrylate (HEMA). In the second step, the resulting MA‐multifunctional PIB‐based crosslinker, PIB(MA)_n, with an average functionality of approximately four methacrylic groups per chain, was copolymerized with methacrylic acid (MAA) or acrylic acid (AA) by radical mechanism in tetrahydrofuran giving rise to amphiphilic conetworks containing 31–79 mol % of MAA or 26–36 mol % of AA. The synthesized conetworks were characterized with solid‐state ¹³C‐NMR spectroscopy and differential scanning calorimetry. The amphiphilic nature of the conetworks was proven by swelling in both aqueous media with low and high pH and n‐heptane. The effect of varying pH on the swelling behavior of the synthesized conetworks is presented. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1284–1291, 2009     

Comparative analysis of proteomic changes in contrasting flax cultivars upon cadmium exposure

Cadmium (Cd) is classified as a serious pollutant due to its high toxicity, high carcinogenicity, and widespread presence in the environment. Phytoremediation represents an effective low‐cost approach for removing pollutants from contaminated soils, and a crop with significant phytoremediation potential is flax. However, significant differences in Cd accumulation and tolerance were previously found among commercial flax cultivars. Notably, cv. Jitka showed substantially higher tolerance to elevated Cd levels in soil and plant tissues than cv. Tábor. Here, significant changes in the expression of 14 proteins (related to disease/defense, metabolism, protein destination and storage, signal transduction, energy and cell structure) were detected by image and mass spectrometric analysis of two‐dimensionally separated proteins extracted from Cd‐treated cell suspension cultures derived from these contrasting cultivars. Further, two proteins, ferritin and glutamine synthetase (a key enzyme in glutathione biosynthesis), were only up‐regulated by Cd in cv. Jitka, indicating that Cd tolerance mechanisms in this cultivar may include maintenance of low Cd levels at sensitive sites by ferritin and low‐molecular weight thiol peptides binding Cd. The identified changes could facilitate marker‐assisted breeding for Cd tolerance and the development of transgenic flax lines with enhanced Cd tolerance and accumulation capacities for phytoremediating Cd‐contaminated soils.     

Poly­[methyl­ammonium tris(μ2‐form­ato‐κ2O:O′)­cobalt(II)]

The structure of the title compound, {(CH₆N)[Co(CHO₂)₃]}_n, consists of a three‐dimensional net of central Co^II ions connected via formate (methane­diolate) bridges. The negative charge is compensated by protonated methyl­amine cations. The CoO₆ chromophores form slightly distorted octahedra, which are bridged by C atoms of formate groups. The central Co atom lies on an inversion center and most of the other atoms lie on an m plane.     

Mössbauer spectrometer with YAlO3:Ce scintillation crystal

Hyperfine Interactions - A Mössbauer spectrometer has been developed using a mini transducer and a scintillation detector with a YAlO3:Ce crystal. Data acquisition is realised via the PIGGY...     

Synchrotron Production of Photons by a Two-Body System

The power spectrum of the synchrotron radiation generated by the motion of atwo-body charged system in an accelerator is derived in the framework of theSchwinger source theory. The final formula can be used to verify the Lorentzlength contraction of the two-body system moving in the synchrotron.