Colloidal Perovskite Nanocrystal Superlattice Films with Simultaneous Polarized Emission and Orderly Electric Polarity via an In Situ Surface Cross-Linking Reaction.

Superlattices (SLs) based on colloidal nanocrystals (NCs) represent a fascinating structure with long-range and ordered NCs inside the assembled superstructures, displaying great potential application in electronic devices because of the customizable arrangement of building blocks. It is a great challenge to achieve macroscopical SL films by a solution process due to the inherent sensitivity and difficulty in controlling colloidal NCs. In this study, we propose a controllable strategy to create perovskite CsPbBr NC SL films through a surface in situ cross-linking reaction incorporating conjugated linoleic acid (CLA), a naturally polymerizable small molecule.

Producing Freestanding Single-Crystal BaTiO Films through Full-Solution Deposition.

Strontium aluminate, with suitable lattice parameters and environmentally friendly water solubility, has been strongly sought for use as a sacrificial layer in the preparation of freestanding perovskite oxide thin films in recent years. However, due to this material's inherent water solubility, the methods used for the preparation of epitaxial films have mainly been limited to high-vacuum techniques, which greatly limits these films' development. In this study, we prepared freestanding single-crystal perovskite oxide thin films on strontium aluminate using a simple, easy-to-develop, and low-cost chemical full-solution deposition technique.

Postoperative outcomes of minimally invasive versus conventional nipple-sparing mastectomy with prosthesis breast reconstruction in breast cancer: a meta-analysis.

Breast cancer is the most common malignant tumor worldwide, and mastectomy remains the primary strategy for treating early stage breast cancer. However, the complication rates, surgical variables, and oncologic safety of minimally invasive nipple-sparing mastectomy (MINSM) have not been fully addressed. We systematically searched PubMed, Web of Science, Embase, and the Cochrane Library for randomized-controlled trials (RCTs) and non-RCTs that compared MINSM with conventional nipple-sparing mastectomy (CNSM), both followed by Prosthesis Breast Reconstruction (PBR).

High Efficiency and Low Roll-Off Pure-Red Perovskite LED Enabled by Simultaneously Inhibiting Auger and Trap Recombination of Quantum Dots.

CsPbI perovskite quantum dots (QDs) could achieve pure-red emission by reducing their size, but the increased exciton binding energy () and surface defects for the small-sized QDs (SQDs) cause severe Auger and trap recombinations, thus worsening their electroluminescence (EL) performance. Herein, we utilize the dangling bonds of the SQDs as a driving force to accelerate KI dissolution to solve its low solubility in nonpolar solvents, thereby allowing K and I to bond to the surface of SQDs. The of the SQDs was decreased from 305 to 51 meV because of the attraction of K to electrons, meanwhile surface vacancies were passivated by K and I.

Colossal Ferroelectric Photovoltaic Effect in Inequivalent Double-Perovskite BiFeMnO Thin Films.

Double perovskite films have been extensively studied for ferroelectric order, ferromagnetic order, and photovoltaic effects. The customized ion combinations and ordered ionic arrangements provide unique opportunities for bandgap engineering. Here, a synergistic strategy to induce chemical strain and charge compensation through inequivalent element substitution is proposed.

Scalable Synthesis of High-Quality Ultrathin Ferroelectric Magnesium Molybdenum Oxide.

The development of ultrathin, stable ferroelectric materials is crucial for advancing high-density, low-power electronic devices. Nonetheless, ultrathin ferroelectric materials are rare due to the critical size effect. Here, a novel ferroelectric material, magnesium molybdenum oxide (MgMoO) is presented.

Giant tunnelling electroresistance in atomic-scale ferroelectric tunnel junctions.

Ferroelectric tunnel junctions are promising towards high-reliability and low-power non-volatile memories and computing devices. Yet it is challenging to maintain a high tunnelling electroresistance when the ferroelectric layer is thinned down towards atomic scale because of the ferroelectric structural instability and large depolarization field. Here we report ferroelectric tunnel junctions based on samarium-substituted layered bismuth oxide, which can maintain tunnelling electroresistance of 7 × 10 with the samarium-substituted bismuth oxide film down to one nanometer, three orders of magnitude higher than previous reports with such thickness, owing to efficient barrier modulation by the large ferroelectric polarization.

Anion-induced robust ferroelectricity in sulfurized pseudo-rhombohedral epitaxial BiFeO thin films polarization rotation.

Polarization rotation caused by various strains, such as substrate and/or chemical strain, is essential to control the electronic structure and properties of ferroelectric materials. This study proposes anion-induced polarization rotation with chemical strain, which effectively improves ferroelectricity. A method for the sulfurization of BiFeO thin films by introducing sulfur anions is presented.

Development and validation of nomograms for predicting survival outcomes in patients with T1-2N1 breast cancer to identify those who could not benefit from postmastectomy radiotherapy.

Purpose: In this study, we aimed to develop and validate nomograms for predicting the survival outcomes in patients with T1-2N1 breast cancer to identify the patients who could not benefit from postmastectomy radiotherapy (PMRT).

Methods: Data from 10191 patients with T1-2N1 breast cancer were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Of them, 6542 patients who had not received PMRT formed the training set.

Ferroelectricity in layered bismuth oxide down to 1 nanometer.

Atomic-scale ferroelectrics are of great interest for high-density electronics, particularly field-effect transistors, low-power logic, and nonvolatile memories. We devised a film with a layered structure of bismuth oxide that can stabilize the ferroelectric state down to 1 nanometer through samarium bondage. This film can be grown on a variety of substrates with a cost-effective chemical solution deposition.

Heterostructure-Engineered Semiconductor Quantum Dots toward Photocatalyzed-Redox Cooperative Coupling Reaction.

Semiconductor quantum dots have been emerging as one of the most ideal materials for artificial photosynthesis. Here, we report the assembled ZnS-CdS hybrid heterostructure for efficient coupling cooperative redox catalysis toward the oxidation of 1-phenylethanol to acetophenone/2,3-diphenyl-2,3-butanediol (pinacol) integrated with the reduction of protons to H. The strong interaction and typical type-I band-position alignment between CdS quantum dots and ZnS quantum dots result in efficient separation and transfer of electron-hole pairs, thus distinctly enhancing the coupled photocatalyzed-redox activity and stability.

Stereoselective insertion of cyclopropenes into Mg-Mg bonds.

The reaction of cyclopropenes with compounds containing Mg-Mg bonds is reported. 1,2-Dimagnesiation occurs exclusively by -addition to the least hindered face of the alkene forming a single diastereomeric product. DFT calculations support a concerted and stereoselective mechanism.

Role of oxygen vacancies in colossal polarization in SmFeO thin films.

The orthorhombic rare-earth manganates and ferrites multiferroics are promising candidates for the next generation multistate spintronic devices. However, their ferroelectric polarization is small, and transition temperature is far below room temperature (RT). The improvement of ferroelectricity remains challenging.

Direct Observation of Polarization Rotation in the Monoclinic Phase under Electrical Loading.

The monoclinic phase has received a lot of research because of its importance in explaining the origin of high piezoelectric and ferroelectric performances around the morphotropic phase boundary. In the present study, we have investigated the detailed structural evolution in monoclinic PbZrTiO ferroelectric ceramics induced by an electric field with in situ high-energy synchrotron diffraction combined with two-dimensional (2D) geometry scattering technology. It has been discovered that an electric-field-induced single monoclinic phase persists indefinitely.

Chemical-Pressure-Modulated BaTiO Thin Films with Large Spontaneous Polarization and High Curie Temperature.

Although BaTiO is one of the most famous lead-free piezomaterials, it suffers from small spontaneous and low Curie temperature. Chemical pressure, as a mild way to modulate the structures and properties of materials by element doping, has been utilized to enhance the ferroelectricity of BaTiO but is not efficient enough. Here, we report a promoted chemical pressure route to prepare high-performance BaTiO films, achieving the highest remanent polarization, (100 μC/cm), to date and high Curie temperature, (above 1000 °C).

A Combined Computational and Experimental Study of Rh-Catalyzed C-H Silylation with Silacyclobutanes: Insights Leading to a More Efficient Catalyst System.

The study of new C-H silylation reagents and reactions remains an important topic. We reported that under Rh catalysis, silacyclobutanes (SCBs) for the first time were able to react with C(sp)-H and C(sp)-H bonds, however the underlying reasons for such a new reactivity were not understood. Through this combined computational and experimental study on C-H silylation with SCBs, we not only depict a reaction pathway that fully accounts for the reactivity and all the experimental findings but also streamline a more efficient catalyst that significantly improves the reaction rates and yields.

Relationship among the Crystal Structure, Texture, and Macroscopic Properties of Tetragonal (Pb,La)(Zr,Ti)O Ferroelectrics Investigated by In Situ High-Energy Synchrotron Diffraction.

In situ diffraction investigations have played an important role in experimentally revealing the mechanism of piezoelectric and ferroelectric properties. In this study, a pure tetragonal ferroelectric ceramic of La-doped PbZrTiO (LaPZT50) was investigated to eliminate the complex influence of phase coexistence. The electric field evolutions of the crystal structure, domain switching, and lattice deformation of the tetragonal phase have been revealed by in situ high-energy synchrotron X-ray diffraction.

Synthesis of -Phenolic Sulfilimines via an Intermolecular Sulfur Atom Transfer Cascade Reaction.

To expand the toolbox for the synthesis of -phenolic sulfilimines, sigmatropic rearrangements were introduced to the field of sulfilimine chemistry. Herein we report a N-H sulfenylation/[2,3]-sigmatropic rearrangement cascade reaction. This mild reaction enables commercially available thiols to serve as the sulfenylation reagent and generates water as the sole byproduct.

Controllable Ferromagnetism in Super-tetragonal PbTiO through Strain Engineering.

The coupling strain in nanoscale systems can achieve control of the physical properties in functional materials, such as ferromagnets, ferroelectrics, and superconductors. Here, we directly demonstrate the atomic-scale structure of super-tetragonal PbTiO nanocomposite epitaxial thin films, including the extraordinary coupling of strain transition and the existence of the oxygen vacancies. Large strain gradients, both longitudinal and transverse (∼3 × 10 m), have been observed.

Facile difluoromethylation of aliphatic alcohols with an S-(difluoro-methyl)sulfonium salt: reaction, scope and mechanistic study.

A facile and practical approach for the difluoromethylation of aliphatic alcohols with an S-(difluoromethyl)sulfonium salt was developed. A wide variety of alcohols with broad functional groups are compatible to furnish the corresponding alkyl difluoromethyl ethers in good to excellent yields under mild reaction conditions. Control experiments and DFT computational studies suggest that the difluoromethylation of alcohols mainly proceeds via a difluorocarbene pathway involving a five-membered transition state with the participation of water, whose crucial role in this reaction was also elucidated by control experiments.

Rhodium-Catalyzed C═N Bond Formation through a Rebound Hydrolysis Mechanism and Application in β-Lactam Synthesis.

A rhodium-catalyzed reaction of N-hydroxyanilines with diazo compounds to produce α-imino esters was developed. Distinct from the commonly accepted 1,2-H transfer for normal X-H insertion reactions, density functional theory calculations indicate that this transformation proceeds via a novel rebound hydrolysis mechanism. Furthermore, a three-component reaction was explored to synthesize highly functionalized β-lactams in good yields and diastereoselectivities.

Rh(II)/Brønsted Acid Catalyzed General and Highly Diastereo- and Enantioselective Propargylation of in Situ Generated Oxonium Ylides and C-Alkynyl N-Boc N,O-Acetals: Synthesis of Polyfunctional Propargylamines.

The first metal/organo cooperatively catalyzed asymmetric reaction of C-alkynyl N-Boc-protected N,O-acetals with in situ generated oxonium ylides has been developed. This new type of propargylation allows for the efficient synthesis of structurally diverse unreported chiral propargylamines bearing oxa-quaternary stereocenters. The reaction features unprecedented substrate scope and high diastereo- and enantioselectivity.

Ferroelectric Field Effect Tuned Giant Electroresistance in LaSrMnO/BaTiO Heterostructures.

The mediation of metastable state has been approved to be a promising tool to achieve giant modulations of the physical properties in artificial structures. In this work, the metastable state LaSrMnO (LSMO) films with the coexistence of two phases were fabricated on the tensile ferroelectric BaTiO (BTO) substrates. Upon application of pulse electric fields to the BTO substrates, the oxygen vacancies and charge redistribute and result in giant and volatile electroresistance (∼230%) and normal and nonvolatile electroresistance (∼5%) in the LSMO films, respectively.