Evidence for photoinduced electron transfer from the excited state of a conducting polymer onto buckminsterfullerene, C(60), is reported. After photo-excitation of the conjugated polymer with light of energy greater than the pi-pi* gap, an electron transfer to the C(60) molecule is initiated. Photoinduced optical absorption studies demonstrate a different excitation spectrum for the composite as compared to the separate components, consistent with photo-excited charge transfer. A photoinduced electron spin resonance signal exhibits signatures of both the conducting polymer cation and the C(60) anion. Because the photoluminescence in the conducting polymer is quenched by interaction with C(60), the data imply that charge transfer from the excited state occurs on a picosecond time scale. The charge-separated state in composite films is metastable at low temperatures.

https://science.sciencemag.org/content/sci/258/5087/1474.full.pdf

Photoinduced electron transfer from a conducting polymer to buckminsterfullerene.

An anthraquinone-linked duplex DNA oligomer containing 60 base pairs was synthesized by PCR. The strand complementary to the quinone-containing strand has four isolated GG steps, which serve as traps for a migrating radical cation. Irradiation of the quinone leads to electron transfer from the DNA to the quinone forming the anthraquinone radical anion and a base radical cation. The radical cation migrates through the DNA, causing reaction at GG steps revealed as strand breaks. The efficiency of strand cleavage falls off exponentially with distance from the quinone (slope = −0.02 Å−1). This finding necessitates reinterpretation of mechanisms proposed for radical cation migration in DNA. We propose that radical cations form self-trapped polarons that migrate by thermally activated hopping.

https://www.pnas.org/content/pnas/96/15/8353.full.pdf

Long-distance charge transport in duplex DNA: The phonon-assisted polaron-like hopping mechanism

A charge neutral complex (CNC) was formed in aqueous solution by combining an orange light emitting anionic conjugated polyelectrolyte and a saturated cationic polyelectrolyte at a 1:1 ratio (per repeat unit). Photoluminescence (PL) from the CNC can be quenched by both the negatively charged dinitrophenol (DNP) derivative, (DNP-BS(-)), and positively charged methyl viologen (MV(2+)). Use of the CNC minimizes nonspecific interactions (which modify the PL) between conjugated polyelectrolytes and biopolymers. Quenching of the PL from the CNC by the DNP derivative and specific unquenching on addition of anti-DNP antibody (anti-DNP IgG) were observed. Thus, biosensing of the anti-DNP IgG was demonstrated.

https://www.pnas.org/content/pnas/99/1/49.full.pdf

Biosensors from conjugated polyelectrolyte complexes

Three perceptual experiments using natural-sounding instrument tones arranged in concurrently sounding pairs investigate a problem of orchestration: what factors determine selection of instruments to achieve various degrees of "blend" (fusion of multiple timbres into a single timbral image). The principal finding concerns the spectral centroid of the instruments (the midpoint of the spectral energy distribution). Blend worsened as a function of the overall centroid height of the combination (the centroid of the composite spectrum of the pair) or as the amount of difference between the centroids of the two instruments increased. Slightly different results were found depending on whether the instruments were on the same pitch or separated by a minor third. For unisons, composite centroid, attack similarity, and loudness envelope correlation accounted for 51% of the variance of blend. For minor thirds, centroid difference, composite centroid, attack similarity, and synchrony of offset accounted for 63% of the variance of blend. In a third experiment, instruments were manipulated to have different centroid levels to test if centroid made an independent contribution to blend. The results show that changes in centroid affect blend even when that is the only aspect of the sound that is changing. The findings create the potential for an approach to orchestration based on abstract properties of sound as a substitute for the traditional approach of teaching entirely by example.

Roles for Spectral Centroid and Other Factors in Determining "Blended" Instrument Pairings in

Roles for Spectral Centroid and Other Factors in Determining "Blended" Instrument Pairings in Orchestration

Part I On conducting: the teachable technique of conducting idiosyncrasies of conducting orchestral playing and conducting. Part 2 The science of the orchestra: the bow instruments the wind instruments the brass the percussion the harp. Part 3 Conductor and music: the techniques of conducting the applied technique, or practice, of conducting practical examples.

M. D. Calvocoressi

Papers

Handbook of conducting

Masters of Russian music

The principles and methods of musical criticism

A survey of Russian music

Modest Mussorgsky, his life and works