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These data suggest that decreases in plasma free-VEGF levels are greater after treatment with aflibercept or bevacizumab compared with ranibizumab at 4 weeks. At 52 and 104 weeks, a greater decrease was observed in bevacizumab versus ranibizumab. Results from 2 subgroups of participants who did not receive injections within at least 1 month and 2 months before collection suggest similar changes in VEGF levels after stopping injections. It is unknown whether VEGF levels return to normal as the drug is cleared from the system or whether the presence of the drug affects the assay's ability to accurately measure free VEGF. No significant associations between VEGF concentration and systemic factors were noted.

The investigation of partially deuterated methoxy radicals is important because the symmetry lowering from C to C provides new insights into the couplings between rovibronic states via Jahn-Teller and spin-orbit interactions. The vibrational spectrum of the partially deuterated methoxy radical CHDO in a matrix of p-H has been recorded. This species was prepared by irradiating a p-H matrix containing deuterated d-nitritomethane (CHDONO) at 3.3 K with laser light at 355 nm. The identification of the radical is based on the photochemical behavior of the precursor and comparison of observed vibrational wavenumbers and infrared (IR) intensities with those predicted from a refined quartic, curvilinear, internal coordinate force field calculated with the coupled-cluster singles and doubles with perturbative triples/cc-pVTZ method. CHDO reacts with H with a rate coefficient (3.5 ± 1.0) × 10 s. Predominantly c-CHDOH and a negligibly small amount of t-CHDOH were produced. This stereoselectivity results from the reaction H + C-CHDOH, which was demonstrated by an additional experiment on irradiation of a CHDOH/Cl/p-H matrix with ultraviolet and IR light to induce the H + CHDOH reaction; only c-CHDOH was observed from this experiment. Even though the energies of transition states and products for the formation of c-CHDOH and t-CHDOH differ by only ∼10 cm, the selective formation of c-CHDOH can be explained by tunneling of the hydrogen atom via an optimal tunneling path. Similarly, the vibronic spectrum for the partially deuterated specie d-methoxy radical (CHDO) was obtained upon irradiation of d-nitritomethane (CHDONO) at 355 nm. Lines associated with the fundamental vibrational modes were observed and assigned; line positions agree with theoretically predicted vibrational wavenumbers. CHDO reacts with H with a rate coefficient (6.0 ± 1.4) × 10 s; CDOH was produced as a major product because the barrier for the formation of CHDOH from H + CHDOH is greater by ∼400 cm. Rate coefficients of the decays of CHO, CHDO, CHDO, and CDO and their corresponding potential energy surfaces are compared.

A primary means to generate hydrated electrons in laboratory experiments is excitation to the charge-transfer-to-solvent (CTTS) state of a solute such as I–(aq), but this initial step in the genesis of e –(aq) has never been simulated directly using ab initio molecular dynamics. We report the first such simulations, combining ground- and excited-state simulations of I–(aq) with a detailed analysis of fluctuations in the Coulomb potential experienced by the nascent solvated electron. What emerges is a two-step picture of the evolution of e –(aq) starting from the CTTS state: I–(aq) + hν → I–*(aq) → I•(aq) + e –(aq). Notably, the equilibrated ground state of e –(aq) evolves from I–*(aq) without any nonadiabatic transitions, simply as a result of solvent reorganization. The methodology used here should be applicable to other photochemical electron transfer processes in solution, an important class of problems directly relevant to photocatalysis and energy transfer.

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