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Fermi's golden rule (FGR) offers an empirical framework for understanding the dynamics of spin–lattice relaxation in magnetic molecules, encompassing mechanisms like direct (one-phonon) and Raman (two-phonon) processes. These principles effectively model experimental longitudinal relaxation rates, denoted as T 1 − 1 . However, under scenarios of increased coupling strength and nonlinear spin–lattice interactions, FGR's applicability may diminish. This paper numerically evaluates the exact spin–lattice relaxation rate kernels, employing the extended dissipaton equation of motion formalism. Our calculations reveal that when quadratic spin–lattice coupling is considered, the rate kernels exhibit a free induction decay-like feature, and the damping rates depend on the interaction strength. We observe that the temperature dependence predicted by FGR significantly deviates from the exact results since FGR ignores the higher order effects and the non-Markovian nature of spin–lattice relaxation. Our methods can be easily extended to study other systems with nonlinear spin–lattice interactions and provide valuable insights into the temperature dependence of T1 in molecular qubits when the coupling is strong. [ABSTRACT FROM AUTHOR]

The molecular dynamics with electronic friction (MDEF) approach can accurately describe nonadiabatic effects at metal surfaces in the weakly nonadiabatic limit. That being said, the MDEF approach treats nuclear motion classically such that the nuclear quantum effects are completely missing in the approach. To address this limitation, we combine Electronic Friction with Ring Polymer Molecular Dynamics (EF-RPMD). In particular, we apply the averaged electronic friction from the metal surface to the centroid mode of the ring polymer. We benchmark our approach against quantum dynamics to show that EF-RPMD can accurately capture zero-point energy as well as transition dynamics. In addition, we show that EF-RPMD can correctly predict the electronic transfer rate near metal surfaces in the tunneling limit as well as the barrier crossing limit. We expect that our approach will be very useful to study nonadiabatic dynamics near metal surfaces when nuclear quantum effects become essential. [ABSTRACT FROM AUTHOR]

Context.--The updated American Society of Clinical Oncology/College of American Pathologists guideline for human epidermal growth factor receptor 2 (HER2) testing in breast cancer requires pathologists to re-evaluate HER2 status. Objective.--To define HER2 status of breast cancer using immunohistochemistry and fluorescence in situ hybridization. Design.--Diagnostic reports of invasive breast cancers made between 2014 and 2018 with HER2 immunohistochemistry and fluorescence in situ hybridization results were retrieved. HER2 status was re-defined using the updated recommendations. Results.--Of 2514 tumors, 89.7% (2254 of 2514) suggested for fluorescence in situ hybridization assay were HER2 immunohistochemistry 2+. Approximately 8.9% (225 of 2514) and 1.4% (35 of 2514) of tumors were of immunohistochemistry 0/1+ and 3+, respectively. Based on the average HER2 copy number and HER2:CEP17 ratio, tumors were assigned into 5 groups, including 13.1% (330 of 2514) group 1 tumors, 2.1% (52 of 2514) group 2 tumors, 1.1% (27 of 2514) group 3 tumors, 7.0% (175 of 2514) group 4 tumors, and 76.8% (1930 of 2514) group 5 tumors. In combination with immunohistochemistry, all tumors in group 2 and group 4 changed HER2 status, from positive and equivocal into negative, respectively, while group 3 tumors remained positive. Comparative analyses of clinicopathologic features of tumors in different groups revealed that group 2 and 4 tumors displayed worse clinicopathologic features than those of group 5, while group 3 tumors shared similar clinicopathologic features to those of group 1. Conclusions.--Following the updated guideline, HER2 status is clearly designated. Significant differences regarding clinical features were observed between tumors in different groups but they share the same HER2 status, suggesting further validation of the accuracy of this diagnostic approach is warranted. (Arch Pathol Lab Med. 2020;144:1097-1107; doi: 10.5858/arpa.2019-0369-OA), Human epidermal growth factor receptor 2 (HER2) status can be revealed by HER2 gene status tested by in situ hybridization (ISH) assay or HER2 protein expression assessed by immunohistochemistry (IHC). [...]

Aqueous rutile TiO2(110) is the most widely studied water–oxide interface, and yet questions about water dissociation are still controversial. Theoretical studies have systematically investigated the influence of the slab thickness on water dissociation energy (Ediss) at 1 monolayer coverage using static density functional theory calculation and found that Ediss exhibits odd–even oscillation with respect to the TiO2 slab thickness. However, less studies have accounted for the full solvation of an aqueous phase using ab initio molecular dynamics due to high computational costs in which only three, four, and five trilayer models of rutile(110)–water interfaces have been simulated. Here, we report Machine Learning accelerated Molecular Dynamics (MLMD) simulations of defect-free rutile(110)–water interfaces, which allows for a systematic study of the slab thickness ranging from 3 to 17 trilayers with much lower costs while keeping ab initio accuracy. Our MLMD simulations show that the dissociation degree of surface water (α) oscillates with the slab thickness and converges to ∼2% as the TiO2 slab becomes thicker. Converting α into dissociation free energy (ΔAdiss) and comparing with dissociation total energy Ediss calculated with a single monolayer of water, we find that the full solvation of the interfaces suppresses surface water from dissociating. It is interesting to note that the machine learning potential trained from the dataset containing exclusively the five trilayer TiO2 model exhibits excellent transferability to other slab thicknesses and further captures the oscillating behavior of surface water dissociation. Detailed analyses indicate that the central plane in odd trilayer slabs modulates the interaction between double trilayers and, thus, the bonding strength between terminal Ti and water, which affects pKa of surface water and water dissociation degree. [ABSTRACT FROM AUTHOR]