Advances in Conjugated Microporous Polymers.

Conjugated microporous polymers (CMPs) are a unique class of materials that combine extended π-conjugation with a permanently microporous skeleton. Since their discovery in 2007, CMPs have become established as an important subclass of porous materials. A wide range of synthetic building blocks and network-forming reactions offers an enormous variety of CMPs with different properties and structures. This has allowed CMPs to be developed for gas adsorption and separations, chemical adsorption and encapsulation, heterogeneous catalysis, photoredox catalysis, light emittance, sensing, energy storage, biological applications, and solar fuels production. Here we review the progress of CMP research since its beginnings and offer an outlook for where these materials might be headed in the future. We also compare the prospect for CMPs against the growing range of conjugated crystalline covalent organic frameworks (COFs).

Hierarchically Porous Silk/Activated-Carbon Composite Fibres for Adsorption and Repellence of Volatile Organic Compounds.

Fabrics comprised of porous fibres could provide effective passive protection against chemical and biological (CB) threats whilst maintaining high air permeability (breathability). Here, we fabricate hierarchically porous fibres consisting of regenerated silk fibroin (RSF) and activated-carbon (AC) prepared through two fibre spinning techniques in combination with ice-templating-namely cryogenic solution blow spinning (Cryo-SBS) and cryogenic wet-spinning (Cryo-WS). The Cryo-WS RSF fibres had exceptionally small macropores (as low as 0.1 µm) and high specific surface areas (SSAs) of up to 79 m2·g-1. The incorporation of AC could further increase the SSA to 210 m2·g-1 (25 wt.% loading) whilst also increasing adsorption capacity for volatile organic compounds (VOCs).

Dimensionality-Driven Metal-Insulator Transition in Spin-Orbit-Coupled SrIrO_{3}.

Upon reduction of the film thickness we observe a metal-insulator transition in epitaxially stabilized, spin-orbit-coupled SrIrO_{3} ultrathin films. By comparison of the experimental electronic dispersions with density functional theory at various levels of complexity we identify the leading microscopic mechanisms, i.e., a dimensionality-induced readjustment of octahedral rotations, magnetism, and electronic correlations. The astonishing resemblance of the band structure in the two-dimensional limit to that of bulk Sr_{2}IrO_{4} opens new avenues to unconventional superconductivity by "clean" electron doping through electric field gating.

Electronic reconstruction at the isopolar LaTiO(3)/LaFeO(3) interface: an X-ray photoemission and density-functional theory study.

We report the formation of a nonmagnetic band insulator at the isopolar interface between the antiferromagnetic Mott-Hubbard insulator LaTiO_{3} and the antiferromagnetic charge transfer insulator LaFeO_{3}. By density-functional theory calculations, we find that the formation of this interface state is driven by the combination of O band alignment and crystal field splitting energy of the t_{2g} and e_{g} bands. As a result of these two driving forces, the Fe 3d bands rearrange and electrons are transferred from Ti to Fe. This picture is supported by x-ray photoelectron spectroscopy, which confirms the rearrangement of the Fe 3d bands and reveals an unprecedented charge transfer up to 1.2±0.2 e^{-}/interface unit cell in our LaTiO_{3}/LaFeO_{3} heterostructures.

Direct k-space mapping of the electronic structure in an oxide-oxide interface.

The interface between LaAlO(3) and SrTiO(3) hosts a two-dimensional electron system of itinerant carriers, although both oxides are band insulators. Interface ferromagnetism coexisting with superconductivity has been found and attributed to local moments. Experimentally, it has been established that Ti 3d electrons are confined to the interface. Using soft x-ray angle-resolved resonant photoelectron spectroscopy we have directly mapped the interface states in k space. Our data demonstrate a charge dichotomy. A mobile fraction contributes to Fermi surface sheets, whereas a localized portion at higher binding energies is tentatively attributed to electrons trapped by O vacancies in the SrTiO(3). While photovoltage effects in the polar LaAlO(3) layers cannot be excluded, the apparent absence of surface-related Fermi surface sheets could also be fully reconciled in a recently proposed electronic reconstruction picture where the built-in potential in the LaAlO(3) is compensated by surface O vacancies serving also as a charge reservoir.

Report of the 2022 Society of Thoracic Surgeons Congenital Heart Surgery Practice Survey.

BACKGROUND: The Society of Thoracic Surgeons Workforce on Congenital Surgery performed a practice survey to analyze contemporary data. METHODS: An electronic survey was sent to congenital heart surgeons in North America. Details on demographics, training paradigm, clinical practice, and work satisfaction were queried, tabulated, and analyzed. RESULTS: Of 312 unique contacts, 201 (64.4%) responded. Of these, 178 (89%) were practicing. The median age was 52 years (interquartile range, 43, 59 years), and 157 (88%) were male. The number of female respondents increased from 12 (7%) in 2015 to 18 (11%) at present. Practice composition was predominantly mixed pediatric and adult (141; 79%), although 15 (8%) surgeons practiced exclusively pediatric surgery. Most surgeons (154; 87%) reported performing the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category 4 and 5 procedures. One-fourth (42; 24%) reported performing fewer than 50 pediatric cases per year, and 18 (10%) stated that their primary role was as a surgical assistant. Individual surgeon case volume was most commonly 100 to 149 total cases (29%). Although one-half (91; 51%) reported their volume as being "just right," 74 (42%) reported that their case volume was "too small." Seventy-six (43%) reported too many surgeons in their region. Of the 201 practicing surgeons, 30 (14.9%) plan retirement in the next 5 years. Most described career satisfaction, with 102 (57%) being very satisfied and 48 (27%) somewhat satisfied. CONCLUSIONS: Although most congenital heart surgeons in North America are satisfied with their careers, more than 40% believe that their caseload is inadequate and that there are too many surgeons in their region. Further analysis is warranted regarding career dissatisfaction and diversity.

Photoemission of a doped Mott insulator: spectral weight transfer and a qualitative Mott-Hubbard description.

The spectral weight evolution of the low-dimensional Mott insulator TiOCl upon alkali-metal dosing has been studied by photoelectron spectroscopy. We observe a spectral weight transfer between the lower Hubbard band and an additional peak upon electron doping, in line with quantitative expectations in the atomic limit for changing the number of singly and doubly occupied sites. This observation is an unconditional hallmark of correlated bands and has not been reported before. In contrast, the absence of a metallic quasiparticle peak can be traced back to a simple one-particle effect.

Two-spinon and orbital excitations of the spin-Peierls system TiOCl.

We combine high-resolution resonant inelastic x-ray scattering with cluster calculations utilizing a recently derived effective magnetic scattering operator to analyze the polarization, excitation energy, and momentum-dependent excitation spectrum of the low-dimensional quantum magnet TiOCl in the range expected for orbital and magnetic excitations (0-2.5 eV). Ti 3d orbital excitations yield complete information on the temperature-dependent crystal-field splitting. In the spin-Peierls phase we observe a dispersive two-spinon excitation and estimate the inter- and intradimer magnetic exchange coupling from a comparison to cluster calculations.