Lattice QCD calculation of π0→e+e−\pi^0\rightarrow e^+ e^- decay

We extend the application of lattice QCD to the two-photon-mediated, order $\alpha^2$ rare decay $\pi^0\rightarrow e^+ e^-$. By combining Minkowski- and Euclidean-space methods we are able to calculate the complex amplitude describing this decay directly from the underlying theories (QCD and QED) which predict this decay. The leading connected and disconnected diagrams are considered; a continuum limit is evaluated and the systematic errors are estimated. We find $\mathrm{Re} \mathcal{A} = 18.60(1.19)(1.04)\,$eV, $\mathrm{Im} \mathcal{A} = 32.59(1.50)(1.65)\,$eV, a more accurate value for the ratio $\frac{\mathrm{Re} \mathcal{A}}{\mathrm{Im} \mathcal{A}}=0.571(10)(4)$ and a result for the partial width $\Gamma(\pi^0\to\gamma\gamma) = 6.60(0.61)(0.67)\,$eV. Here the first errors are statistical and the second systematic. This calculation is the first step in determining the more challenging, two-photon-mediated decay amplitude that contributes to the rare decay $K\to\mu^+\mu^-$

Associations between challenging parenting behavior and creative tendencies of children: the chain mediating roles of positive emotion and creative self-efficacy

BackgroundParenting behavior has been reported to be closely associated with children’s creativity, yet the association between challenging parenting behavior and children’s creative tendencies, as well as the potential mechanisms connecting the two, remains ambiguous. Based on the Social Cognitive Theory and the Self-efficacy Theory, this study aims to examine the correlation between Chinese parents’ challenging parenting behaviors and their children’s creative tendencies, as well as the chain mediating role of children’s positive emotions and creative self-efficacy.MethodsIn total, 2,647 families were surveyed with questionnaires completed by parents on the Challenging Parenting Behaviors Scale and by children on the Positive/Negative Emotions Scale, the Creative Self-efficacy Scale, and the Williams Creative Tendency Test Scale, and analyzed using structural equation modeling (SEM) in SPSS 22.0 and Mplus 8.3.ResultsThe findings indicate that challenging parenting behavior has a positive correlation with children’s positive emotions, creative self-efficacy, and creative tendencies. Through positive emotions, creative self-efficacy, and a chain mediated pathway between these two variables, challenging parenting behaviors increase children’s creative tendencies.ConclusionThe favorable impacts of challenging parenting behaviors on children’s creative tendencies, with the mediating effects of children’s positive emotions and creative self-efficacy, may help Chinese parents better grasp the mechanisms underlying this association

Overexpressed transient receptor potential vanilloid 1 (TRPV1) in lung adenocarcinoma harbours a new opportunity for therapeutic targeting

The specific biological function of transient receptor potential vanilloid 1 (TRPV1) in pathogenesis of lung adenocarcinoma (LUAD) remains unclear. In this study, TRPV1 expression in tumor tissues, primary cells and cell lines of LUAD, as well as the mechanism mediating its hyperexpression were systematically studied. Multiple models and techniques were adopted to elucidate the relationship between TRPV1 hyperexpression and tumor recurrence and metastasis. Results showed that TRPV1 expression was increased in tumor tissues and primary tumor cells of LUAD patients. The increased expression was associated with worse overall survival outcome and raised HIF1α levels. TRPV1 expression in A549 and NCI-H292 cells was increased after pretreatment with cigarette smoke extract or spermine NONOate. Moreover, A549 cells with TRPV1 overexpression has enhanced tumor growth rates in subcutaneous grafted tumor models, and increased intrapulmonary metastasis after tail vein infusion in nude BALB/c nude mice. Mechanistically, TRPV1 overexpression in A549 cells promoted HIF1α expression and nuclear translocation by promoting CREB phosphorylation and activation of NOS1-NO pathway, ultimately leading to accelerated cell proliferation and stronger invasiveness. In addition, based on photothermal effects, CuS-TRPV1 mAb effectively targeted and induced apoptosis of TRPV1-A549 cells both in vivo and in vitro, thereby mitigating tumor growth and metastasis induced by xenotransplantation of TRPV1-A549 cells. In conclusion, TRPV1 hyperexpression in LUAD is a risk factor for tumor progression and is involved in proliferation and migration of tumor cells through activation of HIF1α. Our study also attempted a new strategy inhibiting the recurrence and metastasis of LUAD: by CuS-TRPV1 mAb precisely kill TRPV1 hyperexpression cells through photothermal effects

Disruption of splicing-regulatory elements using CRISPR/Cas9 to rescue spinal muscular atrophy in human iPSCs and mice

We here report a genome-editing strategy to correct spinal muscular atrophy (SMA). Rather than directly targeting the pathogenic exonic mutations, our strategy employed Cas9 and guide-sgRNA for the targeted disruption of intronic splicing-regulatory elements. We disrupted intronic splicing silencers (ISSs, including ISS-N1 and ISS + 100) of survival motor neuron (SMN) 2, a key modifier gene of SMA, to enhance exon 7 inclusion and full-length SMN expression in SMA iPSCs. Survival of splicing-corrected iPSC-derived motor neurons was rescued with SMN restoration. Furthermore, co-injection of Cas9 mRNA from Streptococcus pyogenes (SpCas9) or Cas9 from Staphylococcus aureus (SaCas9) alongside their corresponding sgRNAs targeting ISS-N1 into zygotes rescued 56% and 100% of severe SMA transgenic mice (Smn , SMN2 ). The median survival of the resulting mice was extended to >400 days. Collectively, our study provides proof-of-principle for a new strategy to therapeutically intervene in SMA and other RNA-splicing-related diseases. -/- tg/

Experimental Study on the Effect of Porous Media on the Aerodynamic Performance of Airfoils

Porous media has potential applications in fluid machinery and in aerospace science and engineering due to its excellent drag-reduction properties. We carried out experimental time-resolved particle image velocimetry (TR-PIV) research, laying porous media with different pore densities on the suction side of an airfoil in the low-turbulence recirculation wind tunnel of Nanjing University of Aeronautics and Astronautics to study the effects and mechanisms of porous media on airfoil aerodynamic performance. We also used a smooth airfoil model in the experiment for comparison. Comparing the aerodynamic forces, pressure distributions, and the airfoil’s suction side flow field, we found that the porous media with different pore densities had different effects on the airfoil’s aerodynamic performance. Although the porous media with 20PPI (pores per inch) increased the pressure drag and reduced the airfoil lift, it considerably reduced the friction drag, thus significantly improving the airfoil’s aerodynamic force. The flow visualization results indicated that, although the porous media with 20PPI reduced the circulation of flow velocity around the suction side of airfoil, it also destroyed the vortex structure, broke the low-frequency large-scale vortex into a high-frequency granular vortex, inhibited the amplitude of vortex fluctuation, reduced the shear stress on the airfoil surface, weakened the vortex energy of different modes, and accelerated the vortex’s spatio-temporal evolution

Holistic Prediction of pKa in Diverse Solvents Based on Machine Learning Approach

The acid dissociation constant pKa dictates a molecule’s ionic status, and is a critical physicochemical property in rationalizing acid-base chemistry in solution and in many biological contexts. Although numerous theoretic approaches have been developed for predicating aqueous pKa, fast and accurate prediction of non-aqueous pKas has remained a major challenge. On the basis of iBonD experimental pKa database curated across 39 solvents, a holistic pKa prediction model was established by using machine learning approach. Structural and physical organic parameters combined descriptors (SPOC) were introduced to represent the electronic and structural features of molecules. With SPOC and ionic status labelling (ISL), the holistic models trained with neural network or XGBoost algorithm showed the best prediction performance with MAE value as low as 0.87 pKa unit. The holistic model showed better performance than all the tested single-solvent models (SSMs), verifying the transfer learning features. The capability of prediction in diverse solvents allows for a comprehensive mapping of all the possible pKa correlations between different solvents. The iBonD holistic model was validated by prediction of aqueous pKa and micro-pKa of pharmaceutical molecules and pKas of organocatalysts in DMSO and MeCN with high accuracy. An on-line prediction platform (http://pka.luoszgroup.com) was constructed based on the current model

Working-Together Normative Appeals to Promote Pro-Environmental Donations

Investigating the role of social norms in fostering pro-environmental behaviors is crucial for advancing human efforts toward environmental protection. This study employed a one-way, two-level, between-participants experimental design, focusing on the type of social norm as the independent variable and pro-environmental donations as the dependent variable. This study aimed to explore the impact of working-together normative appeals on pro-environmental donations and to understand the underlying mediating mechanism. In total, 128 Chinese university students participated in an online experiment. The findings indicated that working-together normative appeals significantly increased both the intention to donate and the actual amount of pro-environmental donations in the experimental group compared to those in the control group. Furthermore, the perceived behavioral control and intentions towards pro-environmental donations were identified as mediators in the relationship between social norm categorization and pro-environmental donations. Notably, intentions towards pro-environmental donations alone had a substantial mediating effect. These results underscore the positive influence of working-together normative appeals on pro-environmental donations and offer valuable insights into encouraging active participation in the creation of an eco-friendly society, particularly within a collectivist cultural context

Holistic Prediction of Nucleophilicity and Electrophilicity Based on a Machine Learning Approach

Nucleophilicity and electrophilicity dictate the reactivity of polar organic reactions. In the past decades, Mayr et al. established a quantitative scale for nucleophilicity (N) and electrophilicity (E), which proved to be useful tools for the rationalization of chemical reactivity. In this study, a holistic prediction model was developed through a machine-learning approach. rSPOC, an ensemble molecular representation with structural, physicochemical, and solvent features, was developed for this purpose. With 1115 nucleophiles, 285 electrophiles and 22 solvents, the dataset was currently the largest one for reactivity prediction. The rSPOC model trained with the Extra Trees algorithm showed high accuracy in predicting Mayr’s N and E parameters with R2 of 0.96 and 0.92, MAE of 0.99 and 1.47, respectively. Furthermore, the practical applications of the model, for instance, nucleophilicity prediction of NAD(P)H and a series of enamines showed potential in predicting molecules with unknown reactivity within seconds. An online prediction platform (http://isyn.luoszgroup.com/) was constructed based on the current model, which is available free to the scientific community

Current status and future perspectives on the biological production of polyhydroxyalkanoates

Nowadays, the environmental pollution caused by conventional petroleum-based plastics is one of the most serious problems facing mankind, and it is of great significance to look for alternative plastics with biodegradable feature. Notably, the bioplastics based on polyhydroxyalkanoates (PHA) have been a focus on research and development during the past several decades. In this review, the recent advances on the biological production of PHA were summarized, mainly including biosynthetic pathways and methods, followed by the extraction processes. Furthermore, the current status on PHA production using industrial waste streams was also discussed. For the moment, the relative higher production cost hindered the large-scale biological production of PHA. Therefore, some insightful strategies were presented about the future research and scale production on biological production of PHA