Novel Osmium‐based Coordination Complexes as Photosensitizers for Panchromatic Photodynamic Therapy

Cancer remains a major global malaise requiring the advent of new, efficient and low‐cost treatments. Photodynamic therapy, which combines a photosensitizer and photons to produce cytotoxic reactive oxygen species, has been established as an effective cancer treatment but has yet to become mainstream. One of the main limitations has been the paucity of photosensitizers that are effective over a wide range of wavelengths, can exert their cytotoxic effects in hypoxia, are easily synthesized and produce few if any side effects. To address these shortfalls, three new osmium‐based photosensitizers (TLD1822, TLD1824 and TLD1829) were synthesized and their photophysical and photobiological attributes determined. These photosensitizers are panchromatic (i.e. black absorbers), activatable from 200 to 900 nm and have strong resistance to photobleaching. In vitro studies show photodynamic therapy efficacy with both red and near‐infrared light in normoxic and hypoxic conditions, which translated to good in vivo efficacy of TLD1829 in a subcutaneous murine colon cancer model.     

Multidirectional,multipolarization antennas for scalar and tensor gravitational radiation

Summary Some gravitational radiation antenna designs are discussed which are capable of distinguishing between the spin zero scalar radiation predicted by the Brans-Dicke theory of gravitation and the spin two tensor radiation predicted by the Einstein theory of gravitation. The antennas will also give information concerning the direction to the source of radiation, and will measure the polarization of the tensor radiation. The designs consist of symmetric masses with approapriately spaced and oriented transducers. The transducers are combined to give orthogonal outputs. Linear combinations of these orthogonal outputs then are uniquely associated with the various possible combinations of radiation type, propagation, direction and polarization, orientation. Essay submitted to the 1969 Awards for Essays on Gravity, Gravity Research Foundation, New Boston, New Hampshire.     

A Gedanken Spacecraft that Operates Using the Quantum Vacuum (Dynamic Casimir Effect)

Conventional rockets are not a suitable technology for interstellar missions. Chemical rockets require a very large weight of propellant, travel very slowly compared to light speed, and require significant energy to maintain operation over periods of years. For example, the 722 kg Voyager spacecraft required 13,600 kg of propellant to launch and would take about 80,000 years to reach the nearest star, Proxima Centauri, about 4.3 light years away. There have been various attempts at developing ideas on which one might base a spacecraft that would permit interstellar travel, such as spacewarps. In this paper we consider another suggestion from science fiction and explore how the quantum vacuum might be utilized in the creation of a novel spacecraft. The spacecraft is based on the dynamic Casimir effect, in which electromagnetic radiation is emitted when an uncharged mirror is properly accelerated in vacuum. The radiative reaction produces a dissipative force on the mirror that tends to resist the acceleration of the mirror. This force can be used to accelerate a spacecraft attached to the mirror. We also show that, in principle, one could obtain the power to operate the accelerated mirror in such a spacecraft using energy extracted from the quantum vacuum using the standard Casimir effect with a parallel plate geometry. Unfortunately the method as currently conceived generates a miniscule thrust, and is no more practical than a spacewarp, yet it does provide an interesting demonstration of our current understanding of the physics of the quantized electromagnetic field in vacuum.     

Syntheses and Structural Characterization of Tetrahedral Four-Coordinate Gold(I) Complexes of 1,3,5-Triaza-7-phosphaadamantane. An Example of a Hydrogen-Bond-Directed Supramolecular Assembly

The synthesis and structural characterization of water-soluble four-coordinate gold(I) complexes containing monodentate phosphine ligands are described. The ligands used are 1,3,5-triaza-7-phosphaadamantane (TPA) and its protonated and methylated derivatives, [HTPA]Cl and [MeTPA]I. Formation of the four-coordinate gold(I) species is favored by the small cone angle of the phosphine (102 degrees ) and its ability to form a hydrogen-bonded network between the nitrogen atoms of the ligand and solvent water molecules. The gold center in all four complexes has a nearly regular tetrahedral geometry with an average P-Au-P angle of 109.5 degrees. [(HTPA)(3)(TPA)Au](PF(6))(4).4H(2)O.CH(3)CN(1) crystallizes in the monoclinic space group P2(1)/c (No. 14) with cell constants a = 20.719(3) ?, b = 15.606(2) ?, c = 17.854(2) ?, beta = 114.03(1) degrees, and Z = 4. Refinement of 4977 reflections and 650 parameters yields R = 0.0396 and R(w) = 0.0500. [(TPA)(4)Au]PF(6).1.5HCl.H(2)O (2), crystallizes in the monoclinic space group C2/c (No. 15) with cell constants a = 33.036(7) ?, b = 11.212(2) ?, c = 31.503(5) ?, b = 137.58(1) degrees, and Z = 8. Refinement of 3835 reflections and 470 parameters yields R = 0.0351 and R(w) = 0.0403. [(TPA)(4)Au]Cl(4).6H(2)O (3) was characterized structurally in the cubic space group Fd&thremacr;m (No. 227) with cell constants a = b = c = 20.020(2) ? and Z = 8. Refinement of 290 reflections and 28 parameters yields R = 0.0624 and R(w) = 0.1291. [(MeTPA)(4)Au](PF(6))(5).2CH(3)CN (4) crystallizes in the monoclinic space group C2/c (No. 15) with cell constants a = 23.337(3) ?, b = 14.855(3) ?, c = 35.317(5) ?, b = 97.95(1) degrees, and Z = 8. Refinement of 7840 reflections and 621 parameters yields R = 0.0493 and R(w) = 0.0698.     

Methodology for studying particle–particle triboelectrification in granular materials

A critical challenge for experimental studies of triboelectric charging is to generate reproducible and unambiguous data that can be linked to theoretical concepts. We have developed a methodology to investigate the triboelectric charging of granular materials due solely to particle–particle interactions (i.e. no particle–wall interactions). The methodology is based on a particle flow apparatus that generates a fountain-like flow in which the particles contact only other particles, but no equipment surfaces. Non-contact methods of measuring charge and separating particles by charge are employed so that probe-particle charging does not occur.     

Free surface electrospinning of fibers containing microparticles

Many materials have been fabricated using electrospinning, including pharmaceutical formulations, superhydrophobic surfaces, catalysis supports, filters, and tissue engineering scaffolds. Often these materials can benefit from microparticles included within the electrospun fibers. In this work, we evaluate a high-throughput free surface electrospinning technique to prepare fibers containing microparticles. We investigate the spinnability of polyvinylpyrrolidone (PVP) solutions containing suspended polystyrene (PS) beads of 1, 3, 5, and 10 μm diameter in order to better understand free surface electrospinning of particle suspensions. PS bead suspensions with both 55 kDa PVP and 1.3 MDa PVP were spinnable at 1:10, 1:5, and 1:2 PS:PVP mass loadings for all particle sizes studied. The final average fiber diameters ranged from 0.47 to 1.2 μm and were independent of the particle size and particle loading, indicating that the fiber diameter can be smaller than the particles entrained and can furthermore be adjusted based on solution properties and electrospinning parameters, as is the case for electrospinning of solutions without particles.