Accounts of Chemical Research最新文献

Objective: Limited data exist around the receipt of palliative care (PC) in patients hospitalized with common chronic conditions. We studied the independent predictors, temporal trends in rates of PC utilization in patients hospitalized with acute exacerbation of common chronic diseases. Methods: Population-based cohort study of all hospitalizations with an acute exacerbation of heart disease (HD), cerebrovascular accident (CVA), cancer (CA), and chronic lower respiratory disease (CLRD). Patients aged ≥18 years or older between January 1, 2004, and December 31, 2017, referred for inpatient PC were extracted from the National Inpatient Sample. Poisson regression analyses were used to estimate temporal trends. Results: Between 2004 and 2017, of 91,877,531 hospitalizations, 55.2%, 13.9%, 17.2%, and 13.8% hospitalizations were related to HD, CVA, CA, and CLRD, respectively. There was a temporal increase in the uptake of PC across all disease groups. Age-adjusted estimated rates of PC per 100,000 hospitalizations/year were highest for CA (2308 (95% CI 2249-2366) to 10,794 (95% CI 10,652-10,936)), whereas the CLRD cohort had the lowest rates of PC referrals (255 (95% CI 231-278) to 1882 (95% CI 1821-1943)) between 2004 and 2017, respectively. In the subgroup analysis of patients who died during hospitalization, the CVA group had the highest uptake of PC per 100,000 hospitalizations/year (4979 (95% CI 4918-5040)) followed by CA (4241 (95% CI 4189-4292)), HD (3250 (95% CI 3211-3289)) and CLRD (3248 (95% CI 3162-3405)). Conclusion: PC service utilization is increasing but remains disparate, particularly in patients that die during hospital admission from common chronic conditions. These findings highlight the need to develop a multidisciplinary, patient-centered approach to improve access to PC services in these patients.

Upconversion is a nonlinear optical process in which long-wavelength photons are absorbed by specific material systems and converted into shorter-wavelength light. Yb³⁺–Ln³⁺ (Ln: Er/Ho/Tm) pairs are the most widely studied upconversion systems, demonstrating great success in efficient near-infrared-to-visible light conversion. Nevertheless, further exploration of upconversion luminescence toward shorter wavelengths, especially in the UV region, has achieved limited progress. In comparison with visible light, UV radiation suffers from minimized interference from natural and most artificial light sources. By shifting the emission to the deep UV band, for example, solar interference could be circumvented, enabling highly valuable applications such as solar-blind imaging and labeling. Additionally, due to the higher photon energy in this spectral range, the system could be simultaneously employed for sterilization, phototherapy, and plastic degradation.

To unlock the application potentials of UV-emitting upconversion materials, substantial research efforts have been undertaken in recent years. Specifically, classic visible upconverting Er³⁺ and Tm³⁺ ions have been repurposed for UV emission due to their rich energy levels extending to the UV spectrum region. To effectively populate the high-lying excited states, systematic investigations into doping concentrations, host lattice compositions, and excitation schemes have been conducted. In parallel, Pr³⁺─typically ineffective for near-infrared to visible upconversion─has been established as a prominent candidate for UV upconversion under blue-light excitation. By precisely tuning its 4f¹5d¹ state through host lattice engineering, both the upconversion dynamics and emission characteristics can be strategically optimized.

In this Account, we focus on recent advances in UV upconversion through lanthanide-doped inorganic crystals, primarily drawing upon our research group’s advancements over the past few years. We begin by summarizing the methods for constructing UV upconversion materials based on rational selection of dopant ions and host crystals, including Er³⁺-, Tm³⁺-, and Pr³⁺-based systems. Building on these foundations, we introduce emerging methods for enhancing the UV upconversion emission intensity, encompassing dielectric coupling, plasmonic modulation, and organic surface coating, which all have a certain degree of universality. The subsequent section will focus on the frontier applications of UV upconversion in lighting, imaging, and environmental sciences. In the end, we conclude by providing a summary and a perspective on future directions.

Mononuclear iron enzymes can perform oxidative chemistry that is key to many biological processes, including natural product biosynthesis, DNA repair, and bioremediation. Fe^IV-oxo intermediates are often the active species responsible for this reactivity, as these can abstract an H atom from strong C–H bonds in organic substrates, initiating catalysis.

Chemists have been inspired by these remarkable intermediates for more than 40 years and have synthesized a wide range of biomimetic Fe^IV═O complexes with either S = 1 or S = 2 spin ground states that can react with organic substrates. However, no consensus exists in terms of which are the most reactive species because the steric hindrance that is necessary for the stability of these Fe^IV-oxo species also impacts reactivity toward the substrate.

This Account provides a methodology to study experimentally the geometric and electronic structures of Fe^IV-oxo active sites and understand their contribution to reactivity. These results provide a rationale for understanding the relative reactivities of Fe^IV═O intermediates in different spin states and with different equatorial ligand fields and can guide the design of new iron-based catalysts for oxidative chemistry.

Organic synthesis mediated by graphitic carbon nitrides (g-CNs) became a research hotspot primarily due to a combination of the following aspects: (1) the simple and convenient preparation of the material on a gram scale from inexpensive precursors, (2) the heterogeneous nature of the material, which allows for its easy recovery from the reaction mixture, chemical and thermal stability, and possibility to create nanostructures, such as membranes and thin films, and (3) the effective utilization of sustainable energy─photons in the UVA–vis range, which may be used to drive chemical reactions that are endergonic in the dark. By combining various spectroscopic techniques and the results of theoretical modeling, our group identified three modes of substrate activation by g-CN via (1) photoinduced electron transfer, (2) energy transfer, and (3) proton-coupled electron transfer/hydrogen atom transfer. In this Account, we discuss the chemical structure of the electronically excited state of g-CN. This information may be used to design rational pathways for substrate activation via the above-mentioned mechanisms. Using elemental sulfur (S₈) as a nearly 100% atom-efficient sulfurating agent, we developed a set of methods to incorporate sulfur atom(s) into the organic scaffold by means of g-CN photocatalysis. On the other hand, we identified S₈ as a more selective, compared to O₂, sacrificial oxidant to mediate a few net-oxidative photocatalytic transformations. Among the products of the developed synthetic methods are highly fluorescent heterocycles, artificial flavoring agents, and precursors for organic synthesis. While g-CNs are typically used by the community as photocatalysts under continuous light illumination (the sensitizer is regenerated many times in the catalytic cycle), our group contributed to understanding the ability of this class of materials to undergo photocharging, i.e., to store charges by forming long-lived radical species. We applied photocharged carbon nitrides as donors of electrons and protons in the dark in a series of organic transformations. We outline the current challenges and future development prospects of carbon nitride-mediated organic synthesis. At the same time, we provide guidance on the development of organic catalytic systems and material design at the molecular level.

The rapid adoption of electric vehicles (EVs) and the expansion of grid-scale energy storage applications have driven unprecedented demand for lithium-ion batteries (LIBs), bringing the recycling and sustainable management of spent LIBs to the forefront of public and scientific attention. Given the environmental risks and resource wastage associated with discarded batteries, advancing recycling technologies is crucial to achieving a circular economy and fostering sustainable development. Despite this urgency, current recycling practices remain limited by outdated, fragmented, and energy-intensive technologies that fail to meet the growing demands of scalability, selectivity, and sustainability.

In this Account, we highlight the vital role of innovative recycling strategies in realizing sustainable materials management and summarize our efforts in this area. We categorize recycling technologies into four evolving stages: open-loop recycling, closed-loop recycling, direct recycling, and upcycling. A mechanistic analysis is conducted to elucidate how each strategy facilitates material recovery and regeneration. Special attention is given to how new recycling systems enhance the reaction rates, selectivity, and controllability by modulating thermodynamics and kinetics, leveraging cavitation effects, optimizing charge transfer, tailoring functional groups and bond energy, and reducing ion migration barriers. Through representative case studies from our work, we illustrate how these technologies progressively evolve from basic environmental compliance to enabling a robust circular economy. Finally, we outline the key challenges and future directions for the field, underscoring the importance of intelligent recycling frameworks and integration of sustainable design principles into next-generation battery systems.