Dendrons and Dendritic Terpolymers: Synthesis,Characterization and Self-Assembly Comparison

To the best of our knowledge, this is the very first time that a thorough study of the synthetic procedures, molecular and thermal characterization, followed by structure/properties relationship for symmetric and non-symmetric second generation (2-G) dendritic terpolymers is reported. Actually, the synthesis of the non-symmetric materials is reported for the first time in the literature. Anionic polymerization enables the synthesis of well-defined polymers that, despite the architecture complexity, absolute control over the average molecular weight, as well as block composition, is achieved. The dendritic type macromolecular architecture affects the microphase separation, because different morphologies are obtained, which do not exhibit long range order, and various defects or dislocations are evident attributed to the increased number of junction points of the final material despite the satisfactory thermal annealing at temperatures above the highest glass transition temperature of all blocks. For comparison reasons, the initial dendrons (miktoarm star terpolymer precursors) which are connected to each other in order to synthesize the final dendritic terpolymers are characterized in solution and in bulk and their self-assembly is also studied. A major conclusion is that specific structures are adopted which depend on the type of the core connection between the ligand and the active sites of the dendrons.     

An Application of the Theory of Open Quantum Systems to Model the Dynamics of Party Governance in the US Political System

The Gorini-Kossakowski-Sudarshan-Lindblad equation allows us to model the process of decision making in US elections. The crucial point we attempt to make is that the voter’s mental state can be represented as a superposition of two possible choices for either republicans or democrats. However, reality dictates a more complicated situation: typically a voter participates in two elections, i.e. the congress and the presidential elections. In both elections the voter has to decide between two choices. This very feature of the US election system requires that the mental state is represented by a 2-qubit state corresponding to the superposition of 4 different choices. The main issue is to describe the dynamics of the voters’ mental states taking into account the mental and political environment. What is novel in this paper is that we apply the theory of open quantum systems to social science. The quantum master equation describes the resolution of uncertainty (represented in the form of superposition) to a definite choice.     

Determination of S-adenosylmethionine,S-adenosylhomocysteine,and methylthioadenosine in urine using solvent-modified micellar electrokinetic chromatography

A new approach for direct determination of S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and methylthioadenosine (MTA) in urine was developed based on MEKC by using SDS modified with isobutanol in the presence of PEG-300. Analytes were first extracted with grafted phenylborononic acid. Using a 50 µm internal diameter silica capillary of 32 cm total length filled with 0.05 M SDS, 0.05 M H₃PO₄, 5% (v/v) isobutanol, and 10% (v/v) PEG-300, LOQ of 0.15 µM for SAM and SAH, and 0.2 µM for MTA was reached. Accuracy was 92% for MTA, 109% for SAH, and 105% for SAM, intra- and interday imprecision were <2.5 and ≤3%, respectively. The total time of analysis for one sample was 10 min. Analysis of 30 urine samples from healthy volunteers showed that the median SAM and SAH levels were 12.1 and 0.73 µM, respectively. MTA levels, which were determined in urine for the first time (according to our data), were 0.43 µM, and these values correlated well with the SAM level (r = 0.748, p < 0.01).     

Ionic conductivity,phase composition,and local defect structure of ZrO2-Gd2O3system solid solution crystals

Journal of Solid State Electrochemistry - The crystalline structure, ionic conductivity, and local structure of ZrO2-Gd2O3solid solution crystals have been studied for a wide range of compositions....     

Influence of the solvent on the durability of cellulose acetate films formed from solutions

The authors examine the influence of the nature of the solvent on the time dependence of the strengths of films obtained from solutions of cellulose acetate in various solvents. They found that the durability of the films depends on the nature of the solvent. They have established that as the thermodynamic affinity of the solvent in the film-forming solutions gets worse, the durability of the films passes through a maximum; the nature of the solvent influences the parameter in the equation for the durability, which is responsible for changes in the structure of the polymer.V. I. Lenin Tadzhik State University, Dushanbe. A. M. Gor'kii Ural State University, Sverdlovsk. Translated from Mekhanika Polimerov, No. 2, pp. 360–362, March–April, 1974.     

High-temperature tests of fine-grained dense graphite composites to predict the lifetime of a neutron target converter

The conductivity of graphite composite samples MPG-6 and MPG-7 has been measured before and after 1.4 MeV electron irradiation and heating by alternating current up to temperatures higher than 2500°C, causing the fracture of the samples. It has been shown that both heating and electron irradiation result in a shift of the temperature dependence of the conductivity of the samples, namely, in an increase in conductivity. The measurements of the relative magnetoresistance at helium temperature in fields of ±1.15 T have shown that the imperfection of the macrostructure increases. The noticeable changes in the x-ray phase diagram do not observed up to the fracture of the samples. All the obtained data make it possible to suppose that the ultimate strength and the lifetime of graphite composites are limited by intercrystalline or grain boundaries.     

Characterization of organic substrates bound to cross-linked polystyrenes by 13C NMR spectroscopy

The ¹³C NMR spectra of a wide variety of organic substrates bound to 2% cross-linked polystyrenes may be obtained routinely, provided the resins can be sufficiently swollen. The ¹³C chemical shifts of polymer-bound trityl alcohol, polymer-bound monotrityl ethers of the symmertrical diols HO (CH₂)_nOH (n=2, 4, 6, 7, 9 and 10), and some related intermediates in the solid phase synthesis of insect pheromones are presented. ¹³C shift additivity correlations, differing little from those in free trityl ethers, are drawn.