Since the discovery of amorphous red phosphorus (a‐red P) in 1847, many possible structures have been proposed. However, the exact molecular structure has not yet been determined because of its ...amorphous nature. Herein several methods are used to investigate basic properties of a‐red P. Data from scanning tunneling microscopy (STM) and gel permeation chromatography (GPC) confirm that a‐red P is a linear inorganic polymer with a broad molecular weight distribution. The theoretical single‐molecule elasticities of the possible a‐red P structures are obtained by quantum mechanical (QM) calculations. The experimental single‐molecule elasticity of a‐red P measured by single‐molecule AFM matches with the theoretical result of the zig‐zag ladder structure, indicating that a‐red P may adopt this structure. Although this conclusion needs further validation, this fundamental study represents progress towards solving the structure of a‐red P. It is expected that the strategy utilized in this work can be applied to study other inorganic polymers.
Zig‐zag: Although amorphous red phosphorus (a‐red P) was discovered for more than 170 years, its exact molecular structure is unknown because of its amorphous nature. Results from single‐molecule AFM, quantum mechanical calculations, and scanning tunneling microscopy suggest that a‐red P may adopt a zig‐zag ladder structure (2 in Scheme).
Lanxangia tsaoko’s accurate classifications of different origins and fruit shapes are significant for research in L. tsaoko difference between origin and species as well as for variety breeding, ...cultivation, and market management. In this work, Fourier transform‐near infrared (FT‐NIR) spectroscopy was transformed into two‐dimensional and three‐dimensional correlation spectroscopies to further investigate the spectral characteristics of L. tsaoko. Before building the classification model, the raw FT‐NIR spectra were preprocessed using multiplicative scatter correction and second derivative, whereas principal component analysis, successive projections algorithm, and competitive adaptive reweighted sampling were used for spectral feature variable extraction. Then combined with partial least squares‐discriminant analysis (PLS‐DA), support vector machine (SVM), decision tree, and residual network (ResNet) models for origin and fruit shape discriminated in L. tsaoko. The PLS‐DA and SVM models can achieve 100% classification in origin classification, but what is difficult to avoid is the complex process of model optimization. The ResNet image recognition model classifies the origin and shape of L. tsaoko with 100% accuracy, and without the need for complex preprocessing and feature extraction, the model facilitates the realization of fast, accurate, and efficient identification.
The outbreak of 2019 novel coronavirus disease (COVID-19) in Wuhan, China, has spread rapidly worldwide. In the early stage, we encountered a small but meaningful number of patients who were ...unintentionally scheduled for elective surgeries during the incubation period of COVID-19. We intended to describe their clinical characteristics and outcomes.
We retrospectively analyzed the clinical data of 34 patients underwent elective surgeries during the incubation period of COVID-19 at Renmin Hospital, Zhongnan Hospital, Tongji Hospital and Central Hospital in Wuhan, from January 1 to February 5, 2020.
Of the 34 operative patients, the median age was 55 years (IQR, 43–63), and 20 (58·8%) patients were women. All patients developed COVID-19 pneumonia shortly after surgery with abnormal findings on chest computed tomographic scans. Common symptoms included fever (31 91·2%), fatigue (25 73·5%) and dry cough (18 52·9%). 15 (44·1%) patients required admission to intensive care unit (ICU) during disease progression, and 7 patients (20·5%) died after admission to ICU. Compared with non-ICU patients, ICU patients were older, were more likely to have underlying comorbidities, underwent more difficult surgeries, as well as more severe laboratory abnormalities (eg, hyperleukocytemia, lymphopenia). The most common complications in non-survivors included ARDS, shock, arrhythmia and acute cardiac injury.
In this retrospective cohort study of 34 operative patients with confirmed COVID-19, 15 (44·1%) patients needed ICU care, and the mortality rate was 20·5%.
National Natural Science Foundation of China.
The tandem cyclization of acrylamide with diselenides facilitated by electrochemical oxidation was successfully developed. This strategy provided an environmentally friendly method for the ...construction of C−Se bond. A series of seleno oxindoles with pharmacological activity were obtained by using this well‐designed tandem cyclization strategy. The in vitro antitumor activity of the compounds was also screened through MTT assay. Results showed that the seleno oxindoles exhibited better antitumor activity than other oxindole derivatives.
In this paper we investigate the low energy shear modes in fluid systems with spontaneously broken translations by a specific holographic model. In absence of momentum relaxation, we find that there ...exist two decoupled gapless modes in the transverse channel, one of which is purely diffusive and the other corresponds to vortex like excitations. The diffusive mode is associated with the conservation of momentum and the vortex mode can be viewed as the Goldstone mode of the spontaneous symmetry breaking. Switching on an external source which breaks the translations explicitly but weakly, the would-be gapless modes both get relaxed and acquire a tiny mass gap. Finally, in the strong momentum relaxation regime, we find a (pseudo-)diffusive-to-sound crossover that is set by a momentum gap.
Rechargeable zinc–air batteries (Re‐ZABs) are one of the most promising next‐generation batteries that can hold more energy while being cost‐effective and safer than existing devices. Nevertheless, ...zinc dendrites, non‐portability, and limited charge–discharge cycles have long been obstacles to the commercialization of Re‐ZABs. Over the past 30 years, milestone breakthroughs have been made in technical indicators (safety, high energy density, and long battery life), battery components (air cathode, zinc anode, and gas diffusion layer), and battery configurations (flexibility and portability), however, a comprehensive review on advanced design strategies for Re‐ZABs system from multiple angles is still lacking. This review underscores the progress and strategies proposed so far to pursuit the high‐efficiency Re‐ZABs system, including the aspects of rechargeability (from primary to rechargeable), air cathode (from unifunctional to bifunctional), zinc anode (from dendritic to stable), electrolytes (from aqueous to non‐aqueous), battery configurations (from non‐portable to portable), and industrialization progress (from laboratorial to practical). Critical appraisals of the advanced modification approaches (such as surface/interface modulation, nanoconfinement catalysis, defect electrochemistry, synergistic electrocatalysis, etc.) are highlighted for cost‐effective flexible Re‐ZABs with good sustainability and high energy density. Finally, insights are further rendered properly for the future research directions of advanced zinc–air batteries.
Rechargeable zinc–air batteries are of great significance among metal‐air battery chemistries. However, their commercialization still has a long way to go due to unresolved shortcomings such as zinc dendrites, non‐portability, low cycle performance, and so on. Advanced and practical strategies to tackle these challenges are systematically summarized from multiple angles: rechargeability, air cathodes, zinc anodes, electrolytes, and battery configurations, aiming to provide some value guidance for the rapid development of zinc–air batteries.
Amyloid-β (Aβ) accumulation in the brain is a pivotal event in the pathogenesis of Alzheimer's disease (AD), and its clearance from the brain is impaired in sporadic AD. Previous studies suggest that ...approximately half of the Aβ produced in the brain is cleared by transport into the periphery. However, the mechanism and pathophysiological significance of peripheral Aβ clearance remain largely unknown. The kidney is thought to be responsible for Aβ clearance, but direct evidence is lacking. In this study, we investigated the impact of unilateral nephrectomy on the dynamic changes in Aβ in the blood and brain in both humans and animals and on behavioural deficits and AD pathologies in animals. Furthermore, the therapeutic effects of the diuretic furosemide on Aβ clearance via the kidney were assessed. We detected Aβ in the kidneys and urine of both humans and animals and found that the Aβ level in the blood of the renal artery was higher than that in the blood of the renal vein. Unilateral nephrectomy increased brain Aβ deposition; aggravated AD pathologies, including Tau hyperphosphorylation, glial activation, neuroinflammation, and neuronal loss; and aggravated cognitive deficits in APP/PS1 mice. In addition, chronic furosemide treatment reduced blood and brain Aβ levels and attenuated AD pathologies and cognitive deficits in APP/PS1 mice. Our findings demonstrate that the kidney physiologically clears Aβ from the blood, suggesting that facilitation of Aβ clearance via the kidney represents a novel potential therapeutic approach for AD.
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•Gentiana rigescens will be negatively affected by climate change.•The areas of current highly suitable habitat are significantly reduced in the future climatic condition.•The highly ...suitable areas could be used as a cultivation base for providing high-quality medicinal material.•Multiple chemical information was used to assess the impact of habitat suitability on the quality of medicinal materials.
Gentiana rigescens is an economically important medicinal plant in the subtropical zone in Asia. However, it is unclear how its distribution responds to climate change in the future. This study aims to simulate the effect of climate change on the distribution of G. rigescens by using the maximum entropy (MaxEnt) model and to evaluate the potential impact of habitat suitability on the quality of medicinal materials vis multiple chemical information. In the study, we investigated the suitable habitat fluctuation ranges of G. rigescens under different future climate scenarios at first. Subsequently, the chemical geographical variation of medicinal materials collected from different suitable areas was evaluated based on high-performance liquid chromatography (HPLC) analysis and Fourier-transform mid-infrared (FT-MIR) spectroscopy. The results showed that the areas of highly suitable habitat for G. rigescens was about 23.17 × 104 km2, and more than 98.88% of highly suitable habitat was distributed in the southwest of China. The survival of G. rigescens may be threatened by global climate change in the future. Under the Representative Concentration Pathways 8.5 (RCP8.5) climate scenario, the change ratio of the highly suitable habitat will be −99.22% in 2070. Meanwhile, the centroids of the highly suitable area showed a westward-shifting trend under future emission trajectories. HPLC analysis showed that medicinal materials from highly suitable areas contained higher concentrations of total iridoid glycoside. Analysis results of FT-MIR data combined with OPLS-DA modeling indicated that the overall chemical composition of samples collected from different suitable habitats were different, and the habitat suitability had a stronger effect on the chemical composition in leaf than that in stem and root. Based on the concentration of iridoids and FT-MIR fingerprint, our research demonstrated there was a certain correlation of habitat suitability with the overall chemical variation of G. rigescens. The highly suitable habitat was better for the cultivation of high-quality medicinal materials. In summary, these findings would improve our understanding of the distribution and quality variation of medicinal Gentiana under future climate change. Meanwhile, the study approach based on multiple information integration could provide a useful case for research of other medicinal plants.
Nanoporous metal phosphonates are propelling the rapid development of emerging energy storage, catalysis, environmental intervention, and biology, the performances of which touch many fundamental ...aspects of portable electronics, convenient transportation, and sustainable energy conversion systems. Recent years have witnessed tremendous research breakthroughs in these fields in terms of the fascinating pore properties, the structural periodicity, and versatile skeletons of porous metal phosphonates. This review presents recent milestones of porous metal phosphonate research, from the diversified synthesis strategies for controllable pore structures, to several important applications including adsorption and separation, energy conversion and storage, heterogeneous catalysis, membrane engineering, and biomaterials. Highlights of porous structure design for metal phosphonates are described throughout the review and the current challenges and perspectives for future research in this field are discussed at the end. The aim is to provide some guidance for the rational preparation of porous metal phosphonate materials and promote further applications to meet the urgent demands in emerging applications.
Nanoporous metal phosphonates have shown great potential in facilitating functionality, shapeability, combination, and miniaturization, which offer a multifunctional platform to make breakthroughs in many promising application fields, such as optics, electronics, ionics, membranes, and catalysis. All the recent developments in designing these porous metal phosphonates are summarized here with a special emphasis on the porosity‐property‐functionality relationships.
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