PIK3CA gene mutation status associated with poor prognosis of breast cancer: a retrospective cohort study.

Purpose: PIK3CA gene mutations have been identified in various malignancies, but the prevalence of specific mutations and their role in breast cancer development remain uncertain. This study aimed to investigate the clinicopathological significance and prognostic impact of PIK3CA mutations in breast cancer.

Methods: Five common PIK3CA mutations (H1047R and H1047L in exon 20, and E542K, E545K, and E545D in exon 9) were identified in breast cancer patients using amplification refractory mutation system (ARMS) allele-specific PCR.

Controlled Synthesis and Phase Transition Mechanisms of Palladium Selenide: A First-Principles Study.

Using density functional theory, we carefully calculated the relative stability of monolayer, few-layer, and cluster structures with Penta PdSe, T-phase PdSe, and PdSe-phase. We found that the stability of Penta PdSe increases with the number of layers. The Penta PdSe, T-phase PdSe, and PdSe monolayers are all semiconducting, with band gaps of 1.

Evolutionary Pathways of T-Phase Transition Metal Dichalcogenides: A Comprehensive Study of PtSe Clusters.

Understanding the transition from nonplanar to planar clusters is crucial for the controllable synthesis of transition metal dichalcogenide (TMDC) monolayers. Using PtSe as a model, we investigate how the chemical environment influences the nucleation and growth stages of monolayer PtSe through structure searching and first-principles calculations. We established a comprehensive database of platinum selenide clusters (PtSe, = 1-10), analyzing 2095 unique clusters and identifying 191 stable isomers and 63 structures with the lowest formation energy on the convex hull.

Understanding the Interface Enhancement Mechanisms of CFRP with the Polydopamine-Polyetheramine Interphase at the Molecular Level.

In this work, polydopamine (PDA) and polyetheramine D230 were selected to construct the PDA-D230 interphase between the carbon fiber (CF) and epoxy matrix. Density functional theory (DFT) and molecular dynamics (MD) simulations were performed to explore the interface enhancement mechanisms of a carbon fiber reinforced polymer (CFRP) with the PDA-D230 interphase from the molecular level. The adsorption characteristics of a PDA molecule on the CF surface were investigated using the DFT method.

Catalytic System-Controlled Regioselective 1,2- and 1,4-Carboannulations of [60]Fullerene.

Selective functionalization of fullerenes is an important but challenging topic in fullerene chemistry and synthetic chemistry. Here we present the first example of catalytic system-controlled regioselective 1,2- and 1,4-addition reactions for the flexible and efficient synthesis of novel 1,2- and 1,4-carbocycle-fused fullerenes via a palladium-catalyzed decarboxylative carboannulation process.

Density Functional Theory Study of Methanol Steam Reforming on PtSn(111) and the Promotion Effect of a Surface Hydroxy Group.

Methanol steam reforming (MSR) is studied on a PtSn surface using the density functional theory (DFT). An MSR network is mapped out, including several reaction pathways. The main pathway proposed is CHOH + OH → CHO → CHO → CHO + OH → CHOOH → CHOOH → COOH → COOH + OH → CO + HO.

Understanding and controlling the formation of single-atom site from supported Cu cluster by tuning CeO reducibility: Theoretical insight into the Gd-doping effect on electronic metal-support interaction.

Controlling the formation of single-atom (SA) sites from supported metal clusters is an important and interesting issue to effectively improve the catalytic performance of heterogeneous catalysts. For extensively studied CO oxidation over metal/CeO systems, the SA formation and stabilization under reaction conditions is generally attributed to CO adsorption, however, the pivotal role played by the reducible CeO support and the underlying electronic metal-support interaction (EMSI) are not yet fully understood. Based on a ceria-supported Cu catalyst model, we performed density functional theory calculations to investigate the intrinsic SA formation mechanism and discussed the synergistic effect of Gd-doped CeO and CO adsorption on the SA formation.

Understanding the Effect of Grain Boundaries on the Mechanical Properties of Epoxy/Graphene Composites.

This work presents a molecular dynamics (MD) simulation study on the effect of grain boundaries (GBs) on the mechanical properties of epoxy/graphene composites. Ten types of GB models were constructed and comparisons were made for epoxy/graphene composites containing graphene with GBs. The results showed that the tensile and compressive behaviors, the glass transition temperature (), and the configurations of epoxy/graphene composites were significantly affected by GBs.

A novel frequency-dependent lattice Boltzmann model with a single force term for electromagnetic wave propagation in dispersive media.

Electromagnetic wave simulation is of pivotal importance in the design and implementation of photonic nano-structures. In this study, we developed a lattice Boltzmann model with a single extended force term (LBM-SEF) to simulate the propagation of electromagnetic waves in dispersive media. By reconstructing the solution of the macroscopic Maxwell equations using the lattice Boltzmann equation, the final form only involves an equilibrium term and a non-equilibrium force term.

Two-dimensional metal-organic frameworks as bifunctional electrocatalysts for the oxygen evolution reaction and oxygen reduction reaction (OER/ORR): a theoretical study.

Effective bifunctional catalysts are needed for the two main processes in metal-air batteries (oxygen evolution reaction and oxygen reduction reaction (OER/ORR)) to increase efficiency. Herein, we systematically investigate the stability, electronic structure, and catalytic performance of the OER/ORR of two-dimensional (2D) conducting metal-organic frameworks (MOFs) M(CSe) (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Rh, Pd, Ir, and Pt) by first-principles calculations. The results show that Co(CSe) has an overpotential of 0.

First principles terahertz spectroscopy of molecular crystals: the crucial role of periodic boundary conditions benchmarked with experimental L-ascorbic acid spectra.

The terahertz (THz) region vibration spectral signatures of molecular crystals can usually be ascribed to the low-frequency vibrational modes related to weak intermolecular interactions, van der Waals (vdW) interactions or hydrogen bonding. These interactions collectively dictate the compositional units deviating from their equilibrium configurations. The collective movements are intrinsically long-range, and hence the boundary conditions used for theoretical calculation can affect the corresponding potential energy gradients and alter the vibrational features.

Impacts of different biomass burning emission inventories: Simulations of atmospheric CO concentrations based on GEOS-Chem.

Biomass burning has substantial spatiotemporal variabilities. It contributes significantly to the dynamics of global CO distributions and variances. Quantifying the impacts of biomass burning emissions on atmospheric CO concentrations is essential for global and regional carbon cycles and budgets.

Theoretical mechanism study on the electrochemical benzylation of [60]fullerene derivatives.

The electrochemical methodology is available for the functionalization of fullerenes. However, intricate and ambiguous issues remain to be identified for some electrochemical reactions. In this work, density functional theory (DFT) calculations reveal that the electron delocalization of C in fullerobenzofuran (RF5) and the C-fused lactone (RL6) declines with the electron injection of electrochemistry, and clear active sites can be obtained to react with the electrophilic agent.

Enhancing the Photoinduced Interlayer Charge Transfer and Spatial Separation in Type-II Heterostructure of WS and Asymmetric Janus-MoSSe with Intrinsic Self-Build Electric Field.

Two-dimensional heterostructure manipulation is promising to overcome the high recombination rates and limited redox abilities of photogenerated electron-hole pairs in a single photocatalyst. The built-in electric field () in the type-II heterojunction is normally unfavorable for the desired charge transfer, which is an important but easily neglected issue that needs to be solved. Here, on the basis of the density functional theory (DFT) and the nonadiabatic molecular dynamics (NAMD) calculations, we obtain a type-II band alignment in Janus-MoSSe/WS heterostructure, which meets the band-edge position requirement for water splitting.

Improved nitrogen reduction activity of NbSe tuned by edge chirality.

Efficient catalysts for the electroreduction of N to NH are of paramount importance for sustainable ammonia production. Recently, it was reported that NbSe nanosheets exhibit an excellent catalytic activity for nitrogen reduction under ambient conditions. However, existing theoretical calculations suggested an overpotential over 3.

Copper acetate-facilitated transfer-free growth of high-quality graphene for hydrovoltaic generators.

Direct synthesis of high-quality graphene on dielectric substrates without a transfer process is of vital importance for a variety of applications. Current strategies for boosting high-quality graphene growth, such as remote metal catalyzation, are limited by poor performance with respect to the release of metal catalysts and hence suffer from a problem with metal residues. Herein, we report an effective approach that utilizes a metal-containing species, copper acetate, to continuously supply copper clusters in a gaseous form to aid transfer-free growth of graphene over a wafer scale.

Polysaccharide and conjugate vaccines to generate distinct humoral responses.

is a major cause of community-acquired pneumonia, bacteremia, and meningitis in older adults worldwide. Two pneumococcal vaccines containing capsular polysaccharides are in current use: the polysaccharide vaccine PPSV23 and the glycoconjugate vaccine PCV13. In clinical trials, both vaccines elicit similar opsonophagocytic killing activity.

Machine learning recognition of protein secondary structures based on two-dimensional spectroscopic descriptors.

Protein secondary structure discrimination is crucial for understanding their biological function. It is not generally possible to invert spectroscopic data to yield the structure. We present a machine learning protocol which uses two-dimensional UV (2DUV) spectra as pattern recognition descriptors, aiming at automated protein secondary structure determination from spectroscopic features.

Ultrafast stimulated resonance Raman signatures of lithium polysulfides for shuttling effect characterization: An ab initio study.

The shuttling effect is a crucial obstacle to the practical deployment of lithium sulfur batteries (LSBs). This can be ascribed to the generation of lithium polysulfide (LiPS) redox intermediates that are soluble in the electrolyte. The detailed mechanism of the shuttling, including the chemical structures responsible for the loss of effective mass and the dynamics/kinetics of the redox reactions, are not clear so far.

Can N, S Cocoordination Promote Single Atom Catalyst Performance in CO RR? Fe-N S Porphyrin versus Fe-N Porphyrin.

Single atom catalysts (SACs) are promising electrocatalysts for CO reduction reaction (CO RR), in which the coordination environment plays a crucial role in intrinsic catalytic activity. Taking the regular Fe porphyrin (Fe-N porphyrin) as a probe, the study reveals that the introduction of opposable S atoms into N coordination (Fe-N S porphyrin) allows for an appropriate electronic structural optimization on active sites. Owing to the additional orbitals around the Fermi level and the abundant Fe orbital occupation after S substitution, N, S cocoordination can effectively tune SACs and thus facilitating protonation of intermediates during CO RR.

One-step Ethylene Purification from an Acetylene/Ethylene/Ethane Ternary Mixture by Cyclopentadiene Cobalt-Functionalized Metal-Organic Frameworks.

The separation of ethylene (C H ) from a mixture of ethane (C H ), ethylene (C H ), and acetylene (C H ) at normal temperature and pressure is a significant challenge. The sieving effect of pores is powerless due to the similar molecular size and kinetic diameter of these molecules. We report a new modification method based on a stable ftw topological Zr-MOF platform (MOF-525).

Computational study on the mechanism of hydroboration of CO catalysed by POCOP pincer nickel thiolate complexes: concerted catalysis and hydride transfer by a shuttle.

Hydroboration of carbon dioxide (CO2) catalysed by bis(phosphinite) (POCOP) pincer nickel complexes is among the most efficient homogeneous processes for the reduction of CO2 to the methanol level. Although both POCOP pincer nickel hydride and thiolate complexes are effective catalysts, the latter is far more effective under the same conditions. The mechanism for nickel hydride complexes catalysed reactions is well-established.