ELSA-PSYCHE: An Improved Method for Protecting Pure Shift Spectra from Artifacts.

Numerous 1H-1H J couplings contribute to complex multiplets in 1H nuclear magnetic resonance spectroscopy, leading to an ambiguous spectral assignment, particularly for strongly coupled protons. Although the PSYCHE approach has proven to be effective in simplifying complex spectra by collapsing J couplings, the PSYCHE pure shift spectrum of strongly coupled protons always suffers from sideband artifacts and baseline oscillations, which impede spectral identification. Herein, we introduce a novel universal technique designed to separate artifacts from the desired absorption-mode pure shift signals. This new study will significantly benefit the development of molecular structure elucidations and composition analysis in the fields of chemistry, biochemistry, and metabonomics.

Quality control of pollen products in the market by quantitative analysis of total amino acids with liquid chromatography.

A rapid high-performance liquid chromatography (HPLC) protocol for the determination of amino acids with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization was successfully developed for assessing amino acid levels in six species of representative commercial bee pollen. Based on a poroshell column, a favorable chromatographic separation of seventeen amino acids was achieved in approximately 10 min with satisfactory resolution. The LOD and LOQ of this method were less than 0.034 µg/mL and 0.232 µg/mL, and the intra- and inter-day RSDs ranged between 0.86-5.28 % and 3.21-6.50 %, respectively. The matrix effect (ME) ranged from -8 to 3, implying that the matrix effect was not significant. Under the optimum conditions, the established method was adopted to determine amino acids in six types of bee pollens. The results showed that the total amino acid content ranged from 151.94 mg/g (Rosa rugosa) to 214.52 mg/g (Leonurus artemisia) in the six bee pollen species. Notably, proline (Pro), valine (Val), leucine (Leu), and phenylalanine (Phe) were abundant in the majority of samples. To identify the suspicious samples, principal component analysis (PCA) was performed, and each type of bee pollen was differentiated. Results showed that, in the market, the qualification rate of RR was 100 %, but that of NN was merely 62.5 %, revealing that a few of them were counterfeit. This method offers advantages such as high speed, low cost, and outstanding performance.

Oxide Derivatives of Nb2CTx MXene and Their Application as Electron Transport Layers in Perovskite Solar Cells: Unraveling the Oxidation Process and Functionalization.

In the realm of photovoltaic research, 2D transition metal carbides (MXenes) have gained significant interest due to their exceptional photoelectric capabilities. However, the instability of MXenes due to oxidation has a direct impact on their practical applications. In this work, the oxidation process of Nb2CTx MXene in aqueous systems is methodically simulated at the atomic level and nanosecond timescales, which elucidates the structural variations influenced by the synergistic effects of water and dissolved oxygen, predicting a transition from metal to semiconductor with 44% C atoms replaced by O atoms in Nb2CTx. Moreover, Nb2CTx with varying oxidation degrees is utilized as electron transport layers (ETLs) in perovskite solar cells (PSCs). Favorable energy level alignments with superior electron transfer capability are achieved by controlled oxidation. By further exploring the composites of Nb2CTx to its derivatives, the strong interaction of the nano-composites is demonstrated to be more effective for electron transport, thus the corresponding PSC achieves a better performance with long-term stability compared with the widely used ETLs like SnO2. This work unravels the oxidation dynamics of Nb2CTx and provides a promising approach to designing ETL by exploiting MXenes to their derivatives for photovoltaic technologies.

Sustainable H2O2 production via solution plasma catalysis.

Clean production of hydrogen peroxide (H2O2) with water, oxygen, and renewable energy is considered an important green synthesis route, offering a valuable substitute for the traditional anthraquinone method. Currently, renewable energy-driven production of H2O2 mostly relies on soluble additives, such as electrolytes and sacrificial agents, inevitably compromising the purity and sustainability of H2O2. Herein, we develop a solution plasma catalysis technique that eliminates the need for soluble additives, enabling eco-friendly production of concentrated H2O2 directly from water and O2. Screening over 40 catalysts demonstrates the superior catalytic performance of carbon nitride interacting with discharge plasma in water. High-throughput density functional theory calculations for 68 models, along with machine learning using 29 descriptors, identify cyano carbon nitride (CCN) as the most efficient catalyst. Solution plasma catalysis with the CCN achieves concentrated H2O2 of 20 mmol L-1, two orders of magnitude higher than photocatalysis by the same catalyst. Plasma diagnostics, isotope labeling, and COMSOL simulations collectively validate that the interplay of solution plasma and the CCN accounts for the significantly increased production of singlet oxygen and H2O2 thereafter. Our findings offer an efficient and sustainable pathway for H2O2 production, promising wide-ranging applications across the chemical industry, public health, and environmental remediation.

Electrical Conductivity Characteristic of Polyimide under Long-Term Combined Electron Irradiation and Thermal Cycle in Vacuum.

During long-term operation, low-earth-orbit spacecraft are exposed to a severe environment of electron irradiation and thermal cycle. This affects the electric properties of polyimide, an essential insulation material for spacecraft electrical transmission equipment, particularly the conductivity characteristic. Therefore, this paper investigates the conductivity and its evolution of polyimide after the combination of 20 keV, 8 nA/cm2 electron irradiation, and 243-343 K, 5 K/min thermal cycle in a vacuum environment for 432 h. The results show that the conductivity increases by about 2 orders of magnitude over 432 h, with the threshold field for electric-field-dependent conductivity decreasing. The conductivity growth rate varies, rising during the first 192 h, then increasing in the midelectric field, and decreasing in the high electric field regions. The thermally stimulated depolarization current method demonstrates that increases in γ, ß1, and ß2 trap densities, associated with enhanced motility of end groups, diamines, and dianhydrides after long-chain breaks, lead to higher conductivity and growth rate. Additionally, increases in ß3 and α trap densities, related to increased C═O bonds and free radicals, reduce the threshold field and the conductivity growth rate in the range of 57.0-100.0 kV/mm after 192 h. These findings provide a reference for the performance evaluation and enhancement of spacecraft polyimide materials.

Ultrasonic-Induced Surface Disordering Promotes Photocatalytic Hydrogen Evolution of TiO2.

Surface disordering has been considered an effective strategy for tailoring the charge separation and surface chemistry of semiconductor photocatalysts. A simple but reliable method to create surface disordering is, therefore, urgently needed for the development of high-performance semiconductor photocatalysts and their practical applications. Herein, we report that the ultrasonic processing, which is commonly employed in the dispersion of photocatalysts, can induce the surface disordering of TiO2 and significantly promote its performance for photocatalytic hydrogen evolution. A 40 min ultrasonic treatment of TiO2 (Degussa P25) enhances the photocatalytic hydrogen production by 42.7 times, achieving a hydrogen evolution rate of 1425.4 µmol g-1 h-1 without any cocatalyst. Comprehensive structural, spectral, and electrochemical analyses reveal that the ultrasonic treatment induces the surface disordering of TiO2, and consequently reduces the density of deep electron traps, extends the separation of photogenerated charges, and facilitates the hydrogen evolution reaction relative to oxygen reduction. The ultrasonic treatment manifests a more pronounced effect on disordering the surface of anatase than rutile, agreeing well with the enhanced photocatalysis of anatase rather than rutile. This study demonstrates that ultrasonic-induced surface disordering could be an effective strategy for the activation of photocatalysts and might hold significant implications for the applications in photocatalytic hydrogen evolution, small molecule activation, and biomass conversion.

Revealing oxygen effect on efficiency and stability of quantum dot photovoltaics.

Colloidal quantum dot solar cells (CQDSCs) have received great attention in the development of scalable and stable photovoltaic devices. Despite the high power-conversion-efficiency (PCE) reported, stability investigations are still limited and the exact degradation mechanisms of CQDSCs remain unclear under different atmosphere conditions. In this study, the atmospheric influence on the ZnO electron transport layer material (ETL), halide-passivated lead sulfide CQDs (PbS-PbI2) photoactive layer material and 1,2-ethanedithiol-PbS CQDs (PbS-EDT) hole transport material on device stability in PbS CQDSCs is investigated. It was found that O2 had negligible influence on PbS-PbI2, but it did induce the increase in work function of ZnO ETL and PbS-EDT layers. Notably, the increase of the ZnO work function (WFZnO) induces the formation of interface barrier between ZnO and PbS-PbI2, leading to a deterioration in device efficiency. By further replacing ZnO ETL with SnO2, a multi-interface collaborative CQDSC was constructed to realize the PCE with high stability. This study identifies the efficiency evolution that is inherent in CQDSCs under different atmospheric conditions.

Efficient sugar utilization and high tolerance to inhibitors enable Rhodotorula toruloides C23 to robustly produce lipid and carotenoid from lignocellulosic feedstock.

The utilization of lignocellulosic substrates for microbial oil production by oleaginous yeasts has been evidenced as an economically viable process for industrial-scale biodiesel preparation. Efficient sugar utilization and tolerance to inhibitors are critical for lipid production from lignocellulosic substrates. This study investigated the lignocellulosic sugar utilization and inhibitor tolerance characteristics of Rhodotorula toruloides C23. The results demonstrated that C23 exhibited robust glucose and xylose assimilation irrespective of their ratios, yielding over 21 g/L of lipids and 11 mg/L of carotenoids. Furthermore, C23 exhibited high resistance and efficiently degradation towards toxic inhibitors commonly found in lignocellulosic hydrolysates. The potential molecular mechanism underlying xylose metabolism in C23 was explored, with several key enzymes and signal regulation pathways identified as potentially contributing to its superior lipid synthesis performance. The study highlights R. toruloides C23 as a promising candidate for robust biofuel and carotenoid production through direct utilization of non-detoxified lignocellulosic hydrolysates.

The Uptake, Transfer, and Detoxification of Cadmium in Plants and Its Exogenous Effects.

Cadmium (Cd) exerts a toxic influence on numerous crucial growth and development processes in plants, notably affecting seed germination rate, transpiration rate, chlorophyll content, and biomass. While considerable advances in Cd uptake and detoxification of plants have been made, the mechanisms by which plants adapt to and tolerate Cd toxicity remain elusive. This review focuses on the relationship between Cd and plants and the prospects for phytoremediation of Cd pollution. We highlight the following issues: (1) the present state of Cd pollution and its associated hazards, encompassing the sources and distribution of Cd and the risks posed to human health; (2) the mechanisms underlying the uptake and transport of Cd, including the physiological processes associated with the uptake, translocation, and detoxification of Cd, as well as the pertinent gene families implicated in these processes; (3) the detrimental effects of Cd on plants and the mechanisms of detoxification, such as the activation of resistance genes, root chelation, vacuolar compartmentalization, the activation of antioxidant systems and the generation of non-enzymatic antioxidants; (4) the practical application of phytoremediation and the impact of incorporating exogenous substances on the Cd tolerance of plants.

Solution plasma-cobalt hydroxide-enabled nitrogen fixation.

Solution plasma-Co(OH)2 interaction significantly boosts nitrogen fixation and achieves a high concentration of NOx- at 9.42 mmol L-1. This surpasses the nitrogen content requirement of 7.67 mmol L-1 for commercial nutrient solutions, offering a sustainable approach for nitrogen fixation from nitrogen, water and electricity.