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In this study, the mechanism of self-initiation in spontaneous thermal polymerization of ethyl and n-butyl acrylate is explored using first-principles calculations. Density functional theory (with B3LYP functional and 6-31G* basis set) was used to study [4 + 2] and [2 + 2] cycloaddition reactions on the singlet and triplet potential energy surfaces. Diels−Alder (DA) dimers of ethyl acrylate [6-ethoxy-2-ethoxycarbonyl-3,4-dihydro-2H-pyran (EDP)] and of n-butyl acrylate [6-butoxy-2-butoxycarbonyl-3,4-dihydro-2H-pyran (BDP)] were found to form on the singlet surface via the concerted pathway proposed by Mayo. The formation of diethyl cyclobutane-1,2-dicarboxylate (DECD) and dibutyl cyclobutane-1,2-dicarboxylate (DBCD) via a nonconcerted pathway was identified on the singlet surface of ethyl and n-butyl acrylate, respectively. The presence of a diradical transition state for the formation of the DECD and DBCD was predicted. Triplet potential energy surfaces for the formation of diradical dimer of ethyl and n-butyl acrylate were computed, and the presence of a triplet diradical intermediate was identified for each of the monomers. A low energy monoradical generation mechanism was identified to be involving hydrogen abstraction by a third acrylate monomer from the triplet diradical species. The molecular structure of the computed monoradical species was found to correlate with chain initiating species of the dominant series of peaks in previously reported electrospray ionization-Fourier transform mass spectra of spontaneously polymerized samples of ethyl and n-butyl acrylate. In view of these observations, it is concluded that this self-initiation mechanism is most likely the initiating mechanism in spontaneous thermal polymerization of alkyl acrylates. [ABSTRACT FROM AUTHOR]

This computational study deals with the mechanism of spontaneous initiation in thermal polymerization of alkyl acrylates (e.g., methyl, ethyl, and n-butyl acrylate). The mechanism is presently still unknown. Density-functional theory (DFT) and Møller−Plesset (MP2) calculations are used to explore the Flory and Mayo mechanisms of self-initiation in methyl acrylate. On the singlet surface, a low-barrier, concerted [4 + 2] Diels−Alder mechanism for the formation of a dihydropyran adduct (DA) and a high-barrier nonconcerted [2 + 2] diradical (•M2s•) mechanism for the formation of dimethyl cyclobutane-1,2-dicarboxylate (DCD) were found using B3LYP/6-31G*. Several levels of theory were used to validate the transition states, and the pathways for the DAand DCDformations on the singlet surface were determined using intrinsic reaction coordinate (IRC) calculations. On the triplet surface, a triplet diradical intermediate (•M2t•) was identified that is structurally similar to •M2s•but lower in energy. The spin−orbit coupling constant for crossover of the diradical from singlet to triplet surface was calculated. Monoradical generation from the two intermediates, DAand •M2t•via hydrogen transfer to or from a third methyl acrylate was studied. It was found that generation of two monoradical species was possible from •M2t•and is proposed as a likely explanation for experimentally observed spontaneous-initiation. [ABSTRACT FROM AUTHOR]

We calculated the variational and diffusion quantum Monte Carlo forces using the Hellmann-Feynman theorem and Pulay's correction for the first-row diatomic and triatomic molecules (CO, NO, CO2 and NO2). It is demonstrated that Pulay's correction is important for accurate calculation of forces on non-hydrogen atoms. [ABSTRACT FROM AUTHOR]

We report on the effects of device processing conditions, and of changing the electrode materials, on the switching and negative differential resistance (NDR) behaviour of metal/organic thin film/metal structures. The organic material was an ambipolar molecule containing both electron transporting (oxadiazole) and hole transporting (carbazole) chemical groups. Switching and NDR effects are observed for device architectures with both electrodes consisting of aluminium; optimized switching behaviour is achieved for structures incorporating gold nanoparticles. If one of the Al electrodes is replaced by a higher work function metal or coated with an electron-blocking layer, switching and NDR are no longer observed. The results are consistent with a model based on the creation and destruction of Al filaments within the thin organic layer. [ABSTRACT FROM AUTHOR]

Background/Aims Daratumumab has shown an encouraging antitumor effect in patients with multiple myeloma (MM), and was known to alter the immune properties by off-targeting immunosuppressive cells. Here, we aimed to evaluate the change in absolute lymphocyte count (ALC) as a surrogate marker for predicting survival outcomes of patients treated with daratumumab. Methods Between 2018 and 2021, the medical records of patients with relapsed/refractory MM (RRMM) treated with daratumumab monotherapy at 10 centers in South Korea were reviewed. We collected the ALC data at pre-infusion (D0), day 2 after the first infusion (D2), and prior to the third cycle of daratumumab therapy (D56). Results Fifty patients who were administered at least two cycles of daratumumab were included. Overall response rate was 54.0% after two cycles of daratumumab treatment. On D2, almost all patients experienced a marked reduction in ALC. However, an increase in ALC on D56 (ALCD56) was observed in patients with non-progressive disease, whereas failure of ALC recovery was noted in those with progressive disease. Patients with ALCD56 > 700/μL (n = 39, 78.0%) had prolonged progression-free survival (PFS) and overall survival (OS) than those with ALCD56 ≤ 700/μL (median PFS: 5.8 months vs. 2.6 months, p = 0.025; median OS: 24.1 months vs. 6.1 months, p = 0.004). In addition, ALCD56 >700/μL was a significant favorable prognostic factor for PFS (hazard ratio [HR], 0.22; p = 0.003) and OS (HR, 0.23; p = 0.012). Conclusions Increase in ALC during daratumumab treatment was significantly associated with prolonged survival outcomes in patients with RRMM. The ALC value can predict clinical outcomes in patients treated with daratumumab.

In this study, we attempted to synthesize visible light active nano-sized photocatalysts using metal oxides such as zinc oxide, zirconium oxide, tungsten oxide, and strontium titanium oxide with (MoCl5)2 as a dopant by the simple ball-milling method. Fourier-transform infrared spectroscopy data confirmed the presence of M-O-Mo linkage (M = Zn, Zr, W, and SrTi) in all the molybdenum-doped metal oxides (MoMOs), but only MoZnO inhibited the growth of the bloom-forming Microcystis aeruginosa under visible light in a concentration-dependent manner up to 10 mg/L. Further, structural characterization of MoZnO using FESEM and XRD exhibited the formation of typical hexagonal wurtzite nanocrystals of approximately 4 nm. Hydroxyl radical (·OH), reactive oxygen species (ROS), and lipid peroxidation assays revealed ·OH generated by MoZnO under the visible light seemed to cause peroxidation of the lipid membrane of M. aeruginosa, which led to an upsurge of intracellular ROS and consequently introduced the agglomeration of cyanobacteria. These results demonstrated that nano-sized MoZnO photocatalyst can be easily synthesized in a cost-effective ball-mill method and utilized for biological applications such as the reduction of harmful algal blooms. Further, our study implies that a simple ball-milling method can provide an easy, green, and scalable route for the synthesis of visible light active doped metal oxides.