Parameter-Free and Electron Counting Satisfied Material Representation for Machine Learning Potential Energy and Force Fields.

We proposed a parameter-free volume element representation that satisfies the electron counting model and obtains accurate machine learning potential energy and direct force fitting of randomly perturbed hexagonal BN. Our method preserves permutational, translational, and rotational invariance and can be extended to three-dimensional systems, verified by a system of bulk Si. As a result, we obtained 0.57 meV/atom potential energy root mean squared error (RMSE) and 59 meV/Å force RMSE for perturbed bulk BN systems and 0.43 meV/atom potential energy RMSE and 36 meV/Å force RMSE for perturbed Si systems. In addition, an unbiased perturbation-based data set construction scheme is introduced and a continuous population distribution is obtained with a training data set of 4500, which is about 1 order of magnitude smaller than standard methods based on first-principles molecular dynamics simulations and saves a large amount of computing resources. General validity of our model is verified by structure optimization, molecular dynamics simulations, and extrapolations.

The influence of valence and motivation dimensions of affective states on attentional breadth and the attentional blink.

Affective state has been shown to affect attention, but the affective dimension responsible for attentional effects remains under debate. Some studies suggest that attentional effects depend on the valence dimension of the affective state. Others have proposed that attentional effects depend on the motivational intensity of the affective state. We tested the effect of induced affective states on the attentional blink and attentional breadth. In separate conditions, we induced four affective states with different combinations of valence (positive vs. negative) and motivational intensity (low vs. high). We used an RSVP digit identification task to measure the attentional blink and used the local-global visual processing task to measure attentional breadth. For both tasks, affective pictures were presented before each trial to induce the intended affective state. In Experiment 1, the affective pictures were chosen to have similar average arousal across conditions, whereas in Experiment 2, arousal was allowed to covary with expected motivational intensity. Contrary to previous findings, we found no evidence that affective state influenced either the attentional blink or attention breadth. We found no detectable differences between conditions with positive or negative induced affect, nor between affective state conditions with low or high motivational intensity. For attentional blink, the size of the possible effects was at most a 2-3% change in detection rate. Our results suggest that either the affective induction method is not reliably effective, or there is not a direct relationship between the valence or motivational intensity of affective state and the distribution of attention. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Synthesis, Structure, and Cytotoxicity of Oxaliplatin-Based Platinum(IV) Anticancer Prodrugs Bearing One Axial Fluoride.

Fluorine plays more and more important roles in drug design and development. In recent years, fluorine-containing organic drugs have already been applied in a broad range of therapeutic areas. Herein, we report our attempt to introduce an axial fluorine ligand to Pt(IV) complexes by oxidizing oxaliplatin with electrophilic fluorinating reagents in different protic solvents. The crystal structure of one representative complex is presented. The fluorinated Pt(IV) complexes are further expanded by functionalization with different anhydrides, and their analogues bearing one different axial ligand (OAc or OH group) are also synthesized. Further investigations show that the axial fluorine atom has dramatic effects on the chemical properties of these prodrugs. These new fluorinated Pt(IV) complexes are proved to be stable in physiological conditions. For most of the fluorinated Pt(IV) complexes, a higher reduction potential indicates its greater tendency to be reduced by ascorbate. Introducing an axial fluorine ligand in Pt(IV) complexes does not lead to the increase of their lipophilicity. Moreover, these new fluorinated Pt(IV) complexes show better cytotoxicity than nonfluorinated analogues which may derive from their higher cellular accumulation in cancer cells. Therefore, the good stability and high cytotoxicity of these fluorinated Pt(IV) prodrugs indicate their great potential as a building block for further functionalization.

Melamine in prenatal and postnatal organs in rats.

Melamine can be transferred to fetus in utero through placenta and to infant ex utero by breast feeding. In this study, we characterized the pharmacokinetics of melamine in prenatal and postnatal organs in rats. Single bolus of melamine was administered to pregnant rats at different gestational stages and to infants at different postnatal stages. Distribution of melamine in maternal serum was about 30% higher in late pregnancy than that in early pregnancy; and it was 2 folds higher in postnatal serum in early infants in young adulthood. Distribution of melamine in all postnatal organs was higher than that in prenatal organs. Postnatal kidneys in early infants had the highest maximum concentration and the lowest clearance of melamine than the other postnatal organs. It may relate to the high vulnerability to the toxicity of melamine in this population.