Kinetic and Thermodynamic Studies of Emulsion Polymerization of a Sugar Monomer by Calorimetry with Compensation Heating and Differential Cooling

The kinetic and thermodynamic features of free‐radical batch emulsion polymerization of a sugar monomer (3‐MDG) and butyl acrylate (BA) were investigated in a power compensation calorimeter. The homopolymerizations as well as the copolymerization have been studied. The overall activation energy of 3‐MDG homopolymerization was 140 ± 3.8 kJ · mol^?1, the polymerization enthalpy was ΔH_MDG = ?51.6 ± 1.9 kJ · mol^?1 and the calculated adiabatic temperature rise was ΔT_ad = 78.5 K. The effects of the initiator and the emulsifier concentrations on the 3‐MDG/BA batch copolymerization kinetics and on the colloidal properties of the final sugar latexes were studied at 60 °C. At higher emulsifier and initiator concentration, respectively, the polymerization rate increases and the particle size decreases, but the trends do not conform to the Smith‐Ewart theory. Polydisperse sugar latex particles with a mean diameter in the range of 50–67 nm were obtained.

Relationship between the activation energy and the conversion for BA (open symbols) and 3‐MDG (solid symbols).     

Gradual deviations to BCS superconductivity and Ginzburg-Landau parameters of Zr-Cu amorphous alloys

We report on the superconducting properties of a series of sputtered, amorphous Zr_100–x Cu_x (19x48) alloys. From the thermodynamic parameters, we conclude that there is a very good agreement with the BCS theory on the high-Cu-concentration side. When Zr content increases, and then the coupling strength, a very continuous and progressive deviation from the BCS limit occurs, which is in rather good agreement with theoretical predictions for crystalline alloys. However, a departure develops at high Zr concentration. Despite the surprising behavior of the electronic density of states N(E _F) characteristic of these highly disordered alloys, a correlation is found between N(E _F) and the Ginzburg-Landau parameter .     

Mucocutaneous reactions to antineoplastic agents

Mucocutaneous reaction patterns in patients receiving cancer therapy are not only variable, but in many instances identical patterns are produced by different pathologic mechanisms. For example, patients with leukemia or lymphoma may present with nodular skin lesions that may represent malignant infiltration, septic emboli, vasculitis, or a drug eruption. The most banal skin eruption may signal an impending or ongoing catastrophe. If one is able to make some clinical evaluation regarding the likelihood of a drug being responsible for the mucocutaneous eruption, it may help avoid further clinical or laboratory investigation and patient discomfort. Unfortunately, only a few antineoplastic agents have "characteristic" skin manifestations. If, however, these are kept in mind they may be helpful in the diffential diagnosis of mucocutaneous eruptions occurring in patients treated with cancer chemotherapeutic agents.     

Migration history,migration behavior and selectivity

A series of proportional hazards models are used to study the relationship between migration history and migration behavior for a sample of young adults from the National Longitudinal Survey of Youth. The results support the argument that migration is a selective process. College educated young adults have a greater hazard rate of making an initial migration but a lower hazard rate of re-migration, suggesting they have less need of corrective geographic behavior. Individuals who have moved two or more times are less responsive to national unemployment conditions than first time migrants. Migration is related to the timing of unemployment within a sojourn. The findings suggest that migrant stock is an important determinant of how labor markets function.     

Eutrophication of Tamar Lakes (1975–2003): a case study of land-use impacts, potential solutions and fundamental issues for the Water Framework Directive

Tamar Lakes is comprised of two reservoirs, which are located in South West England and in the headwaters of River Tamar at approximately 135 m above ordnance datum. Upper Tamar Lake (UTL) is a direct feed source reservoir of potable water in North Cornwall. Immediately following completion in 1975, UTL was subject to intense blue‐green algal blooms that continue to the present. These blooms create operational problems for water treatment, especially in hot‐dry years. Lower Tamar Lake (LTL) was constructed as a water supply reservoir in 1819 and became obsolete following UTL coming on‐line. Detailed water quality investigations over a period of some 28 years have confirmed the source of nutrient enrichment that fuels the algal blooms to be agriculturally derived, corresponding with a substantial increase in livestock farming. Associated poor land management practices, such as extensive field drainage and inappropriate slurry disposal to land, are linked with substantial elevations in organic contaminants such as ammonia, biochemical oxygen demand (BOD) and suspended solids (SS) during rainfall events. Evidence demonstrates that both reservoirs act as primary treatment lagoons, substantially reducing the worst of these pollutants and providing significant environmental gain. The implications of the Common Agricultural Policy (CAP), the Water Framework Directive (WFD) and regulatory monitoring are discussed in relation to resource management.     

Spectroscopic analysis of ligand binding to lanthanide-macrocycle platforms

A high-affinity, binary Eu(3+) receptor site consisting of 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) was constructed with the goal of improving the detection of dipicolinic acid (DPA), a major component of bacterial spores. Ternary Eu(DO2A)(DPA)(-) complex solutions (1.0 microM crystallographically characterized TBA x Eu(DO2A)(DPA)) were titrated with EuCl3 (1.0 nM-1.0 mM); increased Eu(3+) concentration resulted in a shift in equilibrium population from Eu(DO2A)(DPA)(-) to Eu(DO2A)(+) and Eu(DPA)(+), which was monitored via the ligand field sensitive (5)D0 --> (7)F3 transition (lambda(em) = 670-700 nm) using luminescence spectroscopy. A best fit of luminescence intensity titration data to a two-state thermodynamic model yielded the competition equilibrium constant (Kc), which in conjunction with independent measurement of the Eu(DPA)(+) formation constant (Ka) allowed calculation of the ternary complex formation constant (Ka'). With this binding affinity by competition (BAC) assay, we determined that Ka' = 10(8.21) M(-1), which is approximately 1 order of magnitude greater than the formation of Eu(DPA)(+). In general, the BAC assay can be employed to determine ligand binding constants of systems where the lanthanide platform (usually a binary complex) is stable and the ligand bound versus unbound states can be spectroscopically distinguished.     

Comparison of the crossed and the Gregorian Mizuguchi-Dragone for wide-field millimeter-wave astronomy

We compare the geometric and physical-optics performance of two configurations of offset dual-reflector antennas that obey the Mizuguchi-Dragone condition. The traditional Gregorian configuration is compared with the larger crossed configuration. These configurations are candidates for experiments that measure the polarization of the cosmic microwave background. Particular attention is given to wide-field performance and polarization fidelity. Both a ray tracer and a physical optics simulation package are used to conclude that the crossed configuration has a larger diffraction-limited field of view, but within this limit both configurations have roughly the same instrumental polarization and both show excellent cross-polarization levels, with the crossed configuration showing approximately 10 dB better performance.     

A finite temperature continuum theory based on interatomic potential in crystalline solids

A finite temperature continuum theory of crystalline solid based on an approximate Helmholtz free energy expression is proposed. The free energy expression is specifically derived for simple implementation in atomistic-based continuum methods (i.e. quasicontinuum method) via the Cauchy–Born rule at finite temperature. It is obtained by the method of statistical moments via the quasi-harmonic approximation together with Taylor series expansion of a given interatomic potential. The phonons are assumed to follow the Bose–Einstein distribution so that the quantum effects at low temperature are accounted for. The resulting free energy is in terms of a given interatomic potential and a simple function of displacement that accounts for thermal expansion. It is employed to formulate two finite temperature continuum methods via Cauchy–Born rule and via the virtual atomic cluster (VAC). It is validated through comparison with experimental results of various thermodynamic quantities. In the case of fcc metals, the proposed free energy expression is shown to be valid for a wide range of temperatures above 50 K.