Controlled free radical polymerization of styrene initiated by a [BPO-polystyrene-(4-acetamido-TEMPO)] macroinitiator

The bulk polymerization of styrene at 125°C was studied using a [BPO-polystyrene-(4-acetamido-TEMPO)] macroinitiator synthesized by a styrene polymerization in the presence of 4-acetamido-2,2,6,6-tetramethylpiperidine-N-oxyl (4-acetamido-TEMPO) and benzoyl peroxide (BPO). The rates of polymerization were independent of the initial macroinitiator concentration and they were very similar to that for the thermal autopolymerization of styrene. Additionally, different types of N-oxyls did not have any effect on the polymerization rate. The number-average molecular weights (M_n) of the obtained polymers agreed very well with theoretical predictions, deviations were observed only at low macroinitiator concentrations. Increasing macroinitiator concentrations resulted in lower magnitudes of the growing molecular weights and reduced polydispersities (M_w/M_n) at the initial stage of the polymerization. The concentration of the polymer chains was calculated, and it was recognized that the concentration of polymer chains increased during the polymerization as a result of an additional radical formation due to the thermal self-initiation of styrene. This thermal self-initiation could be proved qualitatively by the addition of N-oxyl to a macroinitiator polymerization system.     

STUDY OF THE TEMPERATURE AND ENTHALPY OF THERMALLY INDUCED PHASE-TRANSITIONS IN n-ALKANES,THEIR MIXTURES AND FISCHER-TROPSCH WAXES

ABSTRACT

A precise determination of the temperatures and enthalpies of thermally induced various phases of n-alkanes, especially those having the molecular weights in the petroleum wax range, have been done by using a differential scanning calorimeter (DSC). These phase transitional parameters are shown to be dependent on the rate of heating/cooling, particularly on the faster rates. Also, the parameters measured during heating cycle (melting) differ from those obtained during the cooling cycle (crystallization). The typical shape of the solid-solid transition curve in the DSC thermograms(cooling cycle) of even n-alkanes readily distinguishes these from the odd n-alkanes, which is greately influenced by the increase in the carbon numbers in the chain (n-C₃₄ and beyond) and the purity of the sample.High molecular weight n-alkanes also showed instability in the structures at the phase transitions

The formation of solid solutions of n-alkanes have been studied by measuring phase transitional parameters and studying nature of the DSC thermograms of various binary and multicomponent mixtures of n-tetracosane (n-C₂₄) with other n-alkanes. It is observed that the immiscibility between two n-alkanes of the binary mixture begins when chain-length difference between them is more than four carbon atoms. In between the two extremes of solid solution and eutectic formations, there also existed the partial miscibility of two n-alkanes, particularly at high temperatures

The DSC thermograms of multicomponent n-alkane mixtures and Fischer-Tropsch waxes revealed that perfect solid solution is formed when the involved n-alkanes have carbon number very close to each other or the carbon number distribution is in a narrow range with smaller chain n-alkanes dominating.     

A tripartite protein complex with the potential to couple synaptic vesicle exocytosis to cell adhesion in brain

90Yttrium-labeled monoclonal antibodies (mAbs) are likely to be important to radioimmunotherapy (RAIT) of a variety of cancers. The goal of this study was to select and evaluate a form of [90Y]mAb suitable for RAIT and determine conditions for high-yield, reproducible radiolabelings. 90Y-Labelings, at 2-40 mCi levels, of cdr-grafted versions of anti-B-cell lymphoma (hLL2) and anti-CEA (hIMMU-14) mAbs were optimized to >90% incorporations using the macrocyclic chelator DOTA as the metal carrier. In in vitro challenge assays, the stability of mAbs labeled with [90Y]DOTA was better than that of the corresponding [90Y]benzyl-DTPA conjugates. The retention of [90Y]DOTA-hLL2 on Raji tumor cells in vitro was similar to that of the same mAb labeled with [90Y]benzyl-DTPA and was about twice as much as with [125I]hLL2, indicating residualization of metalated mAb. Both [90Y]hLL2 conjugates, prepared using DOTA and Bz-DTPA, had similar maximum tolerated doses of 125 muCi in BALB/c mice and showed no discernible chelator-induced immune responses. Animal biodistribution studies in nude mice bearing Ramos human B-cell lymphoma xenografts revealed similar tumor and tissue uptake over a 10 day period, with the exception of bone uptake which was up to 50% lower for [88Y]DOTA-hLL2 compared to [88Y]Bz-DTPA-hLL2 at time points beyond 24 h. With [90Y]DOTA-hLL2 fragments, in vivo animal tumor dosimetries were inferior to those for the IgG, and kidney uptake was relatively high even with D-lysine administration. The ability of [111In]DOTA-hLL2 to accurately predict [90Y]DOTA-hLL2 biodistribution was established. These preclinical findings demonstrate that [90Y]DOTA-(CDR-grafted) mAbs are suitable for examination in clinical RAIT.     

Perceiving outgroup members as unresponsive: Implications for approach-related emotions, intentions, and behavior.

In 2 studies, the authors investigated the determinants of anger and approach-related intentions and behavior toward outgroup members in interracial interactions. In Study 1, White and Black participants who were led to believe that their interracial interaction partner was not open to an upcoming interaction reported heightened anger and approach-related intentions concerning the interaction, including viewing their partner as hostile, intending to ask sensitive race-relevant questions during the interaction, and planning to blame the partner if the interaction went poorly. Results of Study 2 showed that White participants who received negative feedback about their Black partner's openness to interracial interactions behaved in a hostile manner toward their interaction partner. The findings are discussed in terms of their implications for the quality of interracial interactions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

THERMODYNAMIC FUNCTIONS OF THE SOLID-LIQUID TRANSITION OF HYDROCARBON MIXTURES

The dependences of the melting temperature and the enthalpy of fusion on the composition are the essential factors for modelling precipitation and solubility of solid hydrocarbons in crude oils and crude oil products. Long-chain iso-alkanes and cyclic alkanes must be considered besides of n-alkanes. Therefore a degree of isomerization and cyclization was defined using the refractive index and the carbon number. The melting temperatures and the enthalpies of fusion of different n-alkanes and fractions of crude oil were determined by differential scanning calorimetry. Both parameters can be correlated with the degree of isomerization and cyclization by a quadratic fuction.     

Grain-Size Effects in YSZ Thin-Film Electrolytes

The transport properties of oxygen-ion conducting yttria-stabilized zirconia (YSZ)—featuring mean grain sizes from a few nm up to the μm regime—were studied with regard to grain-size effects. Chemically homogeneous, 8.3 mol% YSZ thin films (thickness approximately 400 nm) were processed on single-crystal sapphire substrates by a sol–gel method. The mean grain size d of the thin films was systematically adjusted to 5 nm≤ d ≤782 nm by (i) a rapid thermal annealing step for conversion into the oxide phase and (ii) a consecutive calcination step at 650°C≤ T _cal (24 h) ≤1400°C for grain growth. The quality of the thin films was examined with respect to chemical homogeneity, crystal structure, grain-size, and grain-boundary properties. Total and specific conductivities of the thin films were characterized by means of electrical impedance spectroscopy at 200°≤ T ≤400°C in ambient air, where a complex nonlinear least-squares approximation was applied to determine the bulk conductivity and the grain-boundary conductivity. Despite grain boundaries being free of second phases, oxygen transport was observed to be impeded by the grain boundaries as the specific grain-boundary conductivity was determined to be two orders of magnitude below the bulk conductivity for thin films with d >36 nm. The transport properties of nanoscaled YSZ thin films (5 nm≤ d ≤36 nm) were modeled by application of the brick-layer model indicating the absence of beneficial grain-size effects at the nanoscale.     

Two Multiplierless Designs for MF Receivers

Admitting coefficients that are sums of powers of 2, two multiplierless designs of digital MF receivers are proposed. Design 1. requires 22 additions per set of six output values. Design 2 requires 11 additions per set of three output values, but there is a strict requirement that the input be a valid MF sequence.     

World protein markets—a supplier’s view

There is a growing need for soy proteins to meet the desire for more protein in the affluent countries and the deficiences of proteins in the “third world.” We are, and are determined to be, a consistent and dependable supplier of soybeans to our global customers. We ask in return that our producers be assured of the freedom to market through a world trade system that is liberal and expanding. U.S. agriculture has moved in the direction of a market system that will allow freedom for producers to respond to growth in demand. An international food policy that is effective and workable must include an expanding system of trade. The language of food crosses every boundary and that is the language we speak in order to expand the horizons of peace.     

Macrophages in mice acutely infected with lymphocytic choriomeningitis virus are primed for nitric oxide synthesis

Following infection of adult mice with lymphocytic choriomeningitis virus (LCMV) there is a well documented suppression of T-cell and B-cell functions concurrent with the strong anti-LCMV immune response. Macrophages have been shown to be infected and activated during acute LCMV infection and there is some evidence to indicate that there is altered antigen presentation in acutely infected mice. We have examined nitric oxide (NO) production by splenic macrophages during acute infection of adult mice. Our results show that these macrophages are primed for production of NO, that the inducible production of NO parallels the immune suppression, and that NO production is dependent on the presence of IFN gamma. However, neither in vivo nor in vitro treatment with N-monomethyl-L-arginine (NMA), a specific inhibitor of nitric oxide synthase, altered the induction or maintenance of virus-induced immune suppression in mice acutely infected with LCMV.