Production of ammonia is currently realized by the Haber-Bosch process, while electrochemical N
fixation under ambient conditions is recognized as a promising green substitution in the near future. A ...lack of efficient electrocatalysts remains the primary hurdle for the initiation of potential electrocatalytic synthesis of ammonia. For cheaper metals, such as copper, limited progress has been made to date. In this work, we boost the N
reduction reaction catalytic activity of Cu nanoparticles, which originally exhibited negligible N
reduction reaction activity, via a local electron depletion effect. The electron-deficient Cu nanoparticles are brought in a Schottky rectifying contact with a polyimide support which retards the hydrogen evolution reaction process in basic electrolytes and facilitates the electrochemical N
reduction reaction process under ambient aqueous conditions. This strategy of inducing electron deficiency provides new insight into the rational design of inexpensive N
reduction reaction catalysts with high selectivity and activity.
Abstract
The colour gamut, a two-dimensional (2D) colour space primarily comprising hue and saturation (HS), lays the most important foundation for the colour display and printing industries. ...Recently, the metasurface has been considered a promising paradigm for nanoprinting and holographic imaging, demonstrating a subwavelength image resolution, a flat profile, high durability, and multi-functionalities. Much effort has been devoted to broaden the 2D HS plane, also known as the CIE map. However, the brightness (B), as the carrier of chiaroscuro information, has long been neglected in metasurface-based nanoprinting or holograms due to the challenge in realising arbitrary and simultaneous control of full-colour HSB tuning in a passive device. Here, we report a dielectric metasurface made of crystal silicon nanoblocks, which achieves not only tailorable coverage of the primary colours red, green and blue (RGB) but also intensity control of the individual colours. The colour gamut is hence extruded from the 2D CIE to a complete 3D HSB space. Moreover, thanks to the independent control of the RGB intensity and phase, we further show that a single-layer silicon metasurface could simultaneously exhibit arbitrary HSB colour nanoprinting and a full-colour hologram image. Our findings open up possibilities for high-resolution and high-fidelity optical security devices as well as advanced cryptographic approaches.
The unfolded protein response (UPR) plays an important role in carcinogenesis, but the functional role and mechanism of UPR‐associated bladder carcinogenesis remain to be characterized. Upon UPR ...activation, ATF6α is activated to upregulate the transcription of UPR target genes. Although the mechanism of ATF6 activation has been studied extensively, the negative regulation of ATF6 stabilization is not well understood. Here, we report that the deubiquitinase otubain 1 (OTUB1) facilitates bladder cancer progression by stabilizing ATF6 in response to endoplasmic reticulum stress. OTUB1 expression is raised in bladder cancer patients. Genetic ablation of OTUB1 markedly inhibited bladder cancer cell proliferation, viability, and migration both in vitro and in vivo. Mechanistically, luciferase pathway screening showed that ATF6 signaling was clearly activated compared with other pathways. OTUB1 was found to activate ATF6 signaling by inhibiting its ubiquitylation, thereby remodeling the stressed cells through transcriptional regulation. Our results show that high OTUB1 expression promotes bladder cancer progression by stabilizing ATF6 and that OTUB1 is a potential therapeutic target in bladder cancer.
Our results show that high OTUB1 expression promotes bladder cancer progression by stabilizing ATF6 and that OTUB1 is a potential therapeutic target in bladder cancer.
NOx− reduction acts a pivotal part in sustaining globally balanced nitrogen cycle and restoring ecological environment, ammonia (NH3) is an excellent energy carrier and the most valuable product ...among all the products of NOx− reduction reaction, the selectivity of which is far from satisfaction due to the intrinsic complexity of multiple‐electron NOx−‐to‐NH3 process. Here, we utilize the Schottky barrier‐induced surface electric field, by the construction of high density of electron‐deficient Ni nanoparticles inside nitrogen‐rich carbons, to facilitate the enrichment and fixation of all NOx− anions on the electrode surface, including NO3− and NO2−, and thus ensure the final selectivity to NH3. Both theoretical and experimental results demonstrate that NOx− anions were continuously captured by the electrode with largely enhanced surface electric field, providing excellent Faradaic efficiency of 99 % from both electrocatalytic NO3− and NO2− reduction. Remarkably, the NH3 yield rate could reach the maximum of 25.1 mg h−1 cm−2 in electrocatalytic NO2− reduction reaction, outperforming the maximum in the literature by a factor of 6.3 in neutral solution. With the universality of our electrocatalyst, all sorts of available electrolytes containing NOx− pollutants, including seawater or wastewater, could be directly used for ammonia production in potential through sustainable electrochemical technology.
The tunable surface electric field induced by Schottky barrier boosts the reduction of NOx− in water for ammonia production. The tunable amounts of Ni nanoparticles inside a nitrogen‐rich carbon support could gradually enhance the surface electric field for enriching and fixation of NOx− anions, achieving a high Faradaic efficiency of 99 % for ammonia production from both electrocatalytic NO3− and NO2− reduction.
Potassium and nitrogen are essential macronutrients for plant growth and have a positive impact on crop yield. Previous studies have indicated that the absorption and translocation of K+ and NO3
− ...are correlated with each other in plants; however, the molecular mechanism that coordinates K+ and NO3
− transport remains unknown. In this study, using a forward genetic approach, we isolated a low-K+-sensitive Arabidopsis thaliana mutant, lks2, that showed a leaf chlorosis phenotype under low-K+ conditions. LKS2 encodes the transporter NRT1.5/NPF7.3, a member of the NRT1/PTR (Nitrate Transporter 1/Peptide Transporter) family. The lks2/nrt1.5 mutants exhibit a remarkable defect in both K+ and NO3
− translocation from root to shoot, especially under low-K+ conditions. This study demonstrates that LKS2 (NRT1.5) functions as a proton-coupled H+/K+ antiporter. Proton gradient can promote NRT1.5-mediated K+ release out of root parenchyma cells and facilitate K+ loading into the xylem. This study reveals that NRT1.5 plays a crucial role in K+ translocation from root to shoot and is also involved in the coordination of K+/NO3
− distribution in plants.
Purpose
To investigate the role of computed tomography (CT) radiomics for the preoperative prediction of lymph node (LN) metastasis in gastric cancer.
Materials and methods
This retrospective study ...included 247 consecutive patients (training cohort, 197 patients; test cohort, 50 patients) with surgically proven gastric cancer. Dedicated radiomics prototype software was used to segment lesions on preoperative arterial phase (AP) CT images and extract features. A radiomics model was constructed to predict the LN metastasis by using a random forest (RF) algorithm. Finally, a nomogram was built incorporating the radiomics scores and selected clinical predictors. Receiver operating characteristic (ROC) curves were used to validate the capability of the radiomics model and nomogram on both the training and test cohorts.
Results
The radiomics model showed a favorable discriminatory ability in the training cohort with an area under the curve (AUC) of 0.844 (95% CI, 0.759 to 0.909), which was confirmed in the test cohort with an AUC of 0.837 (95% CI, 0.705 to 0.926). The nomogram consisted of radiomics scores and the CT-reported LN status showed excellent discrimination in the training and test cohorts with AUCs of 0.886 (95% CI, 0.808 to 0.941) and 0.881 (95% CI, 0.759 to 0.956), respectively.
Conclusions
The CT-based radiomics nomogram holds promise for use as a noninvasive tool in the individual prediction of LN metastasis in gastric cancer.
Key Points
• CT radiomics showed a favorable performance for the prediction of LN metastasis in gastric cancer.
• Radiomics model outperformed the routine CT in predicting LN metastasis in gastric cancer.
• The radiomics nomogram holds potential in the individualized prediction of LN metastasis in gastric cancer.
The prevalence and prognosis of digestive system involvement, including gastrointestinal symptoms and liver injury, in patients with COVID-19 remains largely unknown. We aimed to quantify the effects ...of COVID-19 on the digestive system.
In this systematic review and meta-analysis, we systematically searched PubMed, Embase, and Web of Science for studies published between Jan 1, 2020, and April 4, 2020. The websites of WHO, CDC, and major journals were also searched. We included studies that reported the epidemiological and clinical features of COVID-19 and the prevalence of gastrointestinal findings in infected patients, and excluded preprints, duplicate publications, reviews, editorials, single case reports, studies pertaining to other coronavirus-related illnesses, and small case series (<10 cases). Extracted data included author; date; study design; country; patient demographics; number of participants in severe and non-severe disease groups; prevalence of clinical gastrointestinal symptoms such as vomiting, nausea, diarrhoea, loss of appetite, abdominal pain, and belching; and digestive system comorbidities including liver disease and gastrointestinal diseases. Raw data from studies were pooled to determine effect estimates.
We analysed findings from 35 studies, including 6686 patients with COVID-19, that met inclusion criteria. 29 studies (n=6064) reported gastrointestinal symptoms in patients with COVID-19 at diagnosis, and the pooled prevalence of digestive system comorbidities was 4% (95% CI 2-5; range 0-15; I
=74%). The pooled prevalence of digestive symptoms was 15% (10-21; range: 2-57; I
=96%) with nausea or vomiting, diarrhoea, and loss of appetite being the three most common symptoms. The pooled prevalence of abnormal liver functions (12 studies, n=1267) was 19% (9-32; range 1-53; I
=96%). Subgroup analysis showed patients with severe COVID-19 had higher rates of abdominal pain (odds ratio OR 7·10 95% CI 1·93-26·07; p=0·003; I
=0%) and abnormal liver function including increased ALT (1·89 1·30-2·76; p=0·0009; I
=10%) and increased AST (3·08 2·14-4·42; p<0·00001; I
=0%) compared with those with non-severe disease. Patients in Hubei province, where the initial COVID-19 outbreak occurred, were more likely to present with abnormal liver functions (p<0·0001) compared with those outside of Hubei. Paediatric patients with COVID-19 had a similar prevalence of gastrointestinal symptoms to those of adult patients. 10% (95% CI 4-19; range 3-23; I
=97%) of patients presented with gastrointestinal symptoms alone without respiratory features. Patients who presented with gastrointestinal system involvement had delayed diagnosis (standardised mean difference 2·85 95% CI 0·22-5·48; p=0·030; I
=73%). Patients with gastrointestinal involvement tended to have a poorer disease course (eg, acute respiratory distress syndrome OR 2·96 95% CI 1·17-7·48; p=0·02; I
=0%).
Our study showed that digestive symptoms and liver injury are not uncommon in patients with COVID-19. Increased attention should be paid to the care of this unique group of patients.
None.
Crown removal revitalises sand‐fixing shrubs that show declining vigour with age in drought‐prone environments; however, the underlying mechanisms are poorly understood. Here, we addressed this ...knowledge gap by comparing the growth performance, xylem hydraulics and plant carbon economy across different plant ages (10, 21 and 33 years) and treatments (control and crown removal) using a representative sand‐fixing shrub (Caragana microphylla Lam.) in northern China. We found that growth decline with plant age was accompanied by simultaneous decreases in soil moisture, plant hydraulic efficiency and photosynthetic capacity, suggesting that these interconnected changes in plant water relations and carbon economy were responsible for this decline. Following crown removal, quick resprouting, involving remobilisation of root nonstructural carbohydrate reserves, contributed to the reconstruction of an efficient hydraulic system and improved plant carbon status, but this became less effective in older shrubs. These age‐dependent effects of carbon economy and hydraulics on plant growth vigour provide a mechanistic explanation for the age‐related decline and revitalisation of sand‐fixing shrubs. This understanding is crucial for the development of suitable management strategies for shrub plantations constructed with species having the resprouting ability and contributes to the sustainability of ecological restoration projects in water‐limited sandy lands.
Summary statement
Embolism accumulation restricted carbon assimilation in aging shrubs and resulted in growth decline, while the crown‐removal treatment revitalised plants by promoting the construction of new hydraulic systems in resprouts and enhancing carbon balance through the removal of dysfunctional old stems.
Artificial photocatalytic energy conversion represents a highly intriguing strategy for solving the energy crisis and environmental problems by directly harvesting solar energy. The development of ...efficient photocatalysts is the central task for pushing the real-world application of photocatalytic reactions. Due to the maximum atomic utilization efficiency and distinct advantages of outstanding catalytic activity, single-atom catalysts (SACs) have emerged as promising candidates for photocatalysts. In the current review, recent progresses and challenges on SACs for photocatalytic energy conversion systems are presented. Fundamental principles focusing on charge separation/transfer and molecular adsorption/activation for the single-atom photocatalysis are systemically explored. We outline how the isolated reactive sites facilitate the photogenerated electron–hole transfer and promote the construction of efficient photoactivation cycles. The widespread adoption of SACs in diverse photocatalytic reactions is also comprehensively introduced. By presenting these advances and addressing some future challenges with potential solutions related to the integral development of photocatalysis over SACs, we expect to shed some light on the forthcoming research of SACs for photocatalytic energy conversion.
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With the maximum atom utilization and coordinated metal centers, single-atom catalysts (SACs) have emerged as cost-effective platforms for constructing efficient and reusable heterogeneous catalytic systems with selectivity and activity compared to the homogeneous counterparts. Moreover, the simplified and defined structure of SACs allows us to elucidate the structure–activity relationships and unveil the reaction mechanism. Recent progress has revealed the great potential of SACs in photocatalytic energy conversion reactions (e.g., hydrogen evolution, CO2 reduction, etc.). Fundamental achievements on accelerating charge separation/transfer and promoting molecular adsorption/activation over single-atom photocatalysts are herein reviewed.
The introduction of isolated metal atoms could modulate the band structure to enhance the light-harvesting capability of semiconductor supports and also serve as electron pumps to boost the transfer of photoexcited electrons, thus enhancing the surface charge separation/transfer in the single-atom photocatalytic systems. The unsaturated active sites in SACs enable optimizing the adsorption of molecules by tuning the coordination configuration and further activating molecules by efficiently delivering the photoexcited carriers and sharing the fundamental principles resembling the homogeneous and enzymatic catalysts. Due to these distinct advantages, the application of SACs has been extensively studied in diverse, well-known, and emerging photocatalytic reactions ranging from small-molecule activation to the production of fine chemicals. Future developments, including in situ techniques, bioinspired synthesis, and machine learning, are probably basic research needed for understanding the working mechanism of single-atom photocatalysis and advancing SACs toward their integral potential in the photocatalytic systems.
Due to the maximum atomic utilization efficiency and distinct advantages of outstanding catalytic activity, SACs have emerged as promising candidates for pushing the real-world application of photocatalytic energy conversions. This review summarizes the recent progresses and challenges of SACs for photocatalytic systems. Fundamental principles focusing on charge separation/transfer and molecular adsorption/activation for single-atom photocatalysis are systemically explored. We outline how the isolated reactive sites facilitate the photogenerated electron–hole transfer and promote the construction of efficient photoactivation cycles.
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