New application for expanded porphyrins: sapphyrin and heterosapphyrins as inhibitors of Leishmania parasites

Sapphyrins and a series of related porphyrinoid macrocycles have been investigated as potential agents for the treatment of leishmaniasis. The effectiveness of the compounds was evaluated in vitro upon incubation with Leishmania tarentolae or L. panamensis amastigotes and promastigotes. Their effectiveness was also assessed against intracellular L. panamensis. The cytotoxicity of the compounds was evaluated in vitro using the U937 human promonocyte cell line. Effectiveness and cytotoxicity were assessed in the presence and absence of visible light to assess the photodynamic activity of the compounds. Sapphyrin and two related heterosapphyrins were shown to be particularly effective as inhibitors of Leishmania. A photodynamic effect was observed, which may be attributed to the formation of reactive oxygen species. Yields of singlet oxygen ((1)O(2)) produced were determined in ethanol solutions by direct measurement of (1)O(2) phosphorescence. Confocal microscopy demonstrated that sapphyrin and related macrocycles were taken up by the Leishmania cells and that their presence induces the formation of mitochondrial superoxide. Sapphyrins have been widely investigated as anticancer agents and we here show activity against the Leishmania parasites.     

Single-facility scheduling by logic-based Benders decomposition

Logic-based Benders decomposition can combine mixed integer programming and constraint programming to solve planning and scheduling problems much faster than either method alone. We find that a similar technique can be beneficial for solving pure scheduling problems as the problem size scales up. We solve single-facility non-preemptive scheduling problems with time windows and long time horizons. The Benders master problem assigns jobs to predefined segments of the time horizon, where the subproblem schedules them. In one version of the problem, jobs may not overlap the segment boundaries (which represent shutdown times, such as weekends), and in another version, there is no such restriction. The objective is to find feasible solutions, minimize makespan, or minimize total tardiness.     

Laser-driven acceleration of electrons in a partially ionized plasma channel

The generation of quasimonoenergetic electron beams, with energies up to 200 MeV, by a laser-plasma accelerator driven in a hydrogen-filled capillary discharge waveguide is investigated. Injection and acceleration of electrons is found to depend sensitively on the delay between the onset of the discharge current and the arrival of the laser pulse. A comparison of spectroscopic and interferometric measurements suggests that injection is assisted by laser ionization of atoms or ions within the channel.     

Quantum Zeno and anti-Zeno paradoxes

Continuous observation of a time independent projection operator is known to prevent change of state (the quantum Zeno paradox). We discuss the recent result that generic continuous measurement of time dependent projection operators will in fact ensure change of state: an anti-Zeno paradox.     

粉粒体两相流的电容层析成象测量

粉粒体系统中的固相浓度分布的在线测量是十分困难的问题．电容层析成象技术是一种近年来发展起来的非侵入式快速浓度场测量技术．它不干扰流场，不受流动中颗粒浓度、加速度、不透明等因素的制约．本文讨论其测量原理、应用、近期进展、存在的主要问题及其解决的对策．     

Solving Fixed-Charge Network Flow Problems with a Hybrid Optimization and Constraint Programming Approach

We apply to fixed charge network flow (FCNF) problems a general hybrid solution method that combines constraint programming and linear programming. FCNF problems test the hybrid approach on problems that are already rather well suited for a classical 0–1 model. They are solved by means of a global constraint that generates specialized constraint propagation algorithms and a projected relaxation that can be rapidly solved as a minimum cost network flow problem. The hybrid approach ran about twice as fast as a commercial mixed integer programming code on fixed charge transportation problems with its advantage increasing with problem size. For general fixed charge transshipment problems, however, it has no effect because the implemented propagation methods are weak.     

Local canted spin behaviour in Co1.4−x Zn x Ge0.4Fe1.2O4 spinels: A macroscopic, mesoscopic and microscopic study

DC magnetization, neutron depolarization and neutron diffraction (with both polarized and unpolarized neutrons) measurements have been reported for the Co_1.1−x Zn _x Ge_0.1Fe_1.2O₁ spinels with x=0.5, 0.6 and 0.7. Neutron depolarization and neutron diffraction measurements confirm the presence of a long range ferrimagnetic ordering of the local canted spins in these ferrite samples. The observed features of low field magnetization have been explained under the framework of thermally activated domain wall movement of ferrimagnetic arrangement of local canted spins. An important role of magnetic anisotropy (due to the presence of Co²⁺ ions) in establishing the magnetic ordering and domain kinetics in these ferrites has been observed.     

Alternating extraction/injection well interactions forin situ bioremediation

Applied Biochemistry and Biotechnology - The success ofin situ biological contaminant destruction depends on the distribution of microorganisms through a flow field. Using numerical tools, a...