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Hydrogen peroxide is a clean and valuable oxidant that can be produced by photocatalysis under visible light. Developing efficient metal-free photocatalysts for this reaction is a key challenge. To address this challenge, we make two crystalline vinyl-linked covalent organic frameworks, ATP-COF-1 and ATP-COF-2, which contain triphenylamine and tetrazine units. ATP-COF-1 has a hydrogen peroxide production rate of 14,000 μmol g −1 h −1 with an apparent quantum yield of 23.05%, while ATP-COF-2 reaches 12,700 μmol g −1 h −1 and 20.38%. The higher activity originates from efficient photoinduced charge separation, driven by electron transfer between the electron-donating triphenylamine and electron-accepting tetrazine components. Ultrafast spectroscopy confirms prolonged excited-state lifetimes of 351.9 and 277.3 picoseconds, consistent with enhanced charge mobility. In this work, we show that integrating donor-acceptor building blocks within covalent organic frameworks enables efficient and stable visible-light-driven hydrogen peroxide production. Metal-free ATP-COFs efficiently produce hydrogen peroxide under visible light, achieving high rates and selectivity via enhanced charge separation from donor–acceptor building blocks in stable covalent organic frameworks.

Xerostomia is a common adverse effect of radiation therapy at the head and neck area. Radiation-induced xerostomia can be severe and detrimental for the quality of life. Clinicians and radiologists have focused on the prevention of xerostomia as feasible, which has been significantly improved in the recent decades with the use of the contemporary radiation technology. However, radiation-induced xerostomia still remains one of the most devastating side effects of radiation therapy. Clinical risk factors have been identified, but the variation of its incidence and presentation has turned the focus on the investigation of parameters that would be able to predict the onset of acute or chronic xerostomia for each individual patient. Recently, potential imaging parameters and biomarkers are investigated in order for early prediction of the incidence and severity of xerostomia. Here, we compile the resulting imaging biomarkers as have been identified in the recent literature based on MRI and CT performed in correlation with radiation therapy. The identification of such biomarkers is very promising for the prevention and control of xerostomia in the head and neck radiation setting.

Magnetic resonance spectroscopy of biomolecules has recently gained attention for clinical diagnosis. Its combination with saliva collection and analysis can promote early disease detection and monitoring, by identifying biomarkers of specific underlying pathology or disease as detected in saliva. With this novel, non-invasive technique, certain salivary biomarkers have been linked to dental and periodontal tissues pathology, as well as to specific head and neck cancer malignancies. At present, diagnostic biomarkers are still in need for further identification (e.g., diagnosis and monitoring of Sjögren’s syndrome), and nuclear magnetic resonance spectroscopy has been found to be a promising technique to compliment the current analytic methodology. Moreover, this article reports on the various data collection and analysis parameters used in the literature. Protocol standardization is yet to be established not only for the laboratory procedures, but also for the clinical sample collection. Herein, we review the current status of utilizing nuclear magnetic resonance in order to further support data on health associated biomarkers, and we also propose a saliva sampling scheduling protocol with the potential to be used in the clinical and experimental setting for standardization of the testing methodology.

The study objective was to field-validate the technical feasibility of a membrane- and adsorption-enhanced water gas shift reaction process employing a carbon molecular sieve membrane (CMSM)-based membrane reactor (MR) followed by an adsorptive reactor (AR) for pre-combustion CO2 capture. The project was carried out in two different phases. In Phase I, the field-scale experimental MR-AR system was designed and constructed, the membranes, and adsorbents were prepared, and the unit was tested with simulated syngas to validate functionality. In Phase II, the unit was installed at the test site, field-tested using real syngas, and a technoeconomic analysis (TEA) of the technology was completed. All project milestones were met. Specifically, (i) high-performance CMSMs were prepared meeting the target H2 permeance (>1 m3/(m2.hbar) and H2/CO selectivity of >80 at temperatures of up to 300 °C and pressures of up to 25 bar with a <10% performance decline over the testing period; (ii) pelletized adsorbents were prepared for use in relevant conditions (250 °C < T < 450 °C, pressures up to 25 bar) with a working capacity of >2.5 wt.% and an attrition rate of <0.2; (iii) TEA showed that the MR-AR technology met the CO2 capture goals of 95% CO2 purity at a cost of electricity (COE) 30% less than baseline approaches.

Considerable evidence suggests that variations in the properties of topological insulators (TIs) at the nanoscale and at interfaces can strongly affect the physics of topological materials. Therefore, a detailed understanding of surface states and interface coupling is crucial to the search for and applications of new topological phases of matter. Currently, no methods can provide depth profiling near surfaces or at interfaces of topologically inequivalent materials. Such a method could advance the study of interactions. Herein, we present a noninvasive depth-profiling technique based on β-detected NMR (β-NMR) spectroscopy of radioactive ⁸Li⁺ ions that can provide “one-dimensional imaging” in films of fixed thickness and generates nanoscale views of the electronic wavefunctions and magnetic order at topological surfaces and interfaces. By mapping the ⁸Li nuclear resonance near the surface and 10-nm deep into the bulk of pure and Cr-doped bismuth antimony telluride films, we provide signatures related to the TI properties and their topological nontrivial characteristics that affect the electron–nuclear hyperfine field, the metallic shift, and magnetic order. These nanoscale variations in β-NMR parameters reflect the unconventional properties of the topological materials under study, and understanding the role of heterogeneities is expected to lead to the discovery of novel phenomena involving quantum materials.

Tungsten borides, such as tungsten tetraboride (WB4) exhibit a wide range of appealing physical properties, including superhardness, chemical inertness and electronic conductivity. Among the various tungsten borides, the most puzzling remains WB4, with its crystal structure to linger in question for over half a century (Lech et al. in Proc Natl Acad Sci USA 112:3223–3228, 2015). In the present investigation, polycrystalline WB4 samples have been synthesized with two different methods and characterized at the atomic level by combining X-ray diffraction, scanning electron microscopy and nuclear magnetic resonance spectroscopy. The 11B multiple quantum MAS experiment revealed a range of boron sites that were not resolved within the experiment. This result is in contrast to the 11B MAS spectrum of WB2 with four resolved, discernible boron resonances. However, despite the structural complexity and boron-site variety in WB4, the detection of a single exponential of 11B spin–lattice relaxation recovery suggested that all of the boron sites relaxed with a single time constant. The Knight shift (K) was found to be independent of temperature while the \\[ T_{1}^{ - 1} \\] was governed by the Korringa law with a Korringa product T1T = 350 sK across the entire temperature range (168–437 K) of this study. The measured Korringa product was small, indicating substantial spin–lattice relaxation resulting from coupling with the conduction carriers. The abovementioned experimental results not only clearly rule out structures, such as the “MoB4-type phase” of WB4, with the resulting Fermi level in the pseudo-gap as has previously been predicted theoretically; but they also provide a comprehensible and valuable insight into the structural and electronic properties of WB4 at the atomic level.

The study objective was to field-validate the technical feasibility of a membrane- and adsorption-enhanced water gas shift reaction process employing a carbon molecular sieve membrane (CMSM)-based membrane reactor (MR) followed by an adsorptive reactor (AR) for pre-combustion CO capture. The project was carried out in two different phases. In Phase I, the field-scale experimental MR-AR system was designed and constructed, the membranes, and adsorbents were prepared, and the unit was tested with simulated syngas to validate functionality. In Phase II, the unit was installed at the test site, field-tested using real syngas, and a technoeconomic analysis (TEA) of the technology was completed. All project milestones were met. Specifically, (i) high-performance CMSMs were prepared meeting the target H permeance (>1 m /(m .hbar) and H /CO selectivity of >80 at temperatures of up to 300 °C and pressures of up to 25 bar with a <10% performance decline over the testing period; (ii) pelletized adsorbents were prepared for use in relevant conditions (250 °C < T < 450 °C, pressures up to 25 bar) with a working capacity of >2.5 wt.% and an attrition rate of <0.2; (iii) TEA showed that the MR-AR technology met the CO capture goals of 95% CO purity at a cost of electricity (COE) 30% less than baseline approaches.

The study objective was to field-validate the technical feasibility of a membrane- and adsorption-enhanced water gas shift reaction process employing a carbon molecular sieve membrane (CMSM)-based membrane reactor (MR) followed by an adsorptive reactor (AR) for pre-combustion CO[sub.2] capture. The project was carried out in two different phases. In Phase I, the field-scale experimental MR-AR system was designed and constructed, the membranes, and adsorbents were prepared, and the unit was tested with simulated syngas to validate functionality. In Phase II, the unit was installed at the test site, field-tested using real syngas, and a technoeconomic analysis (TEA) of the technology was completed. All project milestones were met. Specifically, (i) high-performance CMSMs were prepared meeting the target H[sub.2] permeance (>1 m[sup.3] /(m[sup.2] .hbar) and H[sub.2] /CO selectivity of >80 at temperatures of up to 300 °C and pressures of up to 25 bar with a <10% performance decline over the testing period; (ii) pelletized adsorbents were prepared for use in relevant conditions (250 °C < T < 450 °C, pressures up to 25 bar) with a working capacity of >2.5 wt.% and an attrition rate of <0.2; (iii) TEA showed that the MR-AR technology met the CO[sub.2] capture goals of 95% CO[sub.2] purity at a cost of electricity (COE) 30% less than baseline approaches.

Understanding different bonding environments in various metal borides provides insight into their structures and physical properties. Polycrystalline aluminum diboride (AlB 2 ) samples have been synthesized and compared both with a commercial sample and with the literature. One issue that arose is the relative ease with which boron-rich and aluminum deficient phases of aluminum borides can be presented in AlB 2 . Here, we report 27 Al, 11 B nuclear magnetic resonance (NMR) spectroscopy and first-principles calculations on AlB 2 in order to shed light on these different bonding environments at the atomic level and compare the structural and electronic properties of the products of different preparations. Along with the aforementioned, the present study also takes an in-depth look at the nature of the 11 B and 27 Al nuclear spin–lattice relaxation recovery data for the AlB 2 and other superhard materials. The nuclear spin–lattice relaxation has been measured for a static sample and with magic-angle spinning. The combination of NMR and band structure calculations highlights the synthetic challenges with superhard materials.

Understanding different bonding environments in various metal borides provides insight into their structures and physical properties. Polycrystalline aluminum diboride (AlB.sub.2) samples have been synthesized and compared both with a commercial sample and with the literature. One issue that arose is the relative ease with which boron-rich and aluminum deficient phases of aluminum borides can be presented in AlB.sub.2. Here, we report .sup.27Al, .sup.11B nuclear magnetic resonance (NMR) spectroscopy and first-principles calculations on AlB.sub.2 in order to shed light on these different bonding environments at the atomic level and compare the structural and electronic properties of the products of different preparations. Along with the aforementioned, the present study also takes an in-depth look at the nature of the .sup.11B and .sup.27Al nuclear spin-lattice relaxation recovery data for the AlB.sub.2 and other superhard materials. The nuclear spin-lattice relaxation has been measured for a static sample and with magic-angle spinning. The combination of NMR and band structure calculations highlights the synthetic challenges with superhard materials.