Insights into N-doping in single-walled carbon nanotubes for enhanced activation of superoxides: A mechanistic study

Emerging characteristics upon nitrogen-doping were differentiated in the activation of superoxides over single-walled carbon nanotubes. Both experimental and theoretical studies revealed that enhanced peroxymonosulfate (PMS) activation is ascribed to a nonradical process while persulfate (PS) activation is accelerated via directly oxidizing water, yet hydrogen peroxide (H2O2) activation is inert to N-doping. This study details the first insights into versatile N-doping in carbocatalysis for organic oxidation in sustainable remediation

Metal-free graphene-carbon nitride hybrids for photodegradation of organic pollutants in water

Hybrid photocatalysts of graphitic carbon nitride (g-C3N4) and reduced graphene oxide (rGO) composites were prepared in one-pot via a thermal condensation of melamine with different amounts of graphene oxide (GO). As metal-free hybrids, the prepared photocatalysts presented enhanced performances in photooxidation of both methylene blue and phenol in water solutions under various light irradiations. The level of rGO significantly affected MB photodegradation efficiencies. The introduced graphene can improve the MB adsorption and optical absorption in visible light region, therefore enables the hybrids to efficiently degrade MB under visible light with wavelengths longer than 430 nm. The metal-free photocatalysts were also able to degrade phenol effectively and the effects of catalyst loading and initial phenol concentration were investigated. This study provided an efficient and environmentally benign photocatalyst for degradation of organic pollutants in water, with complete prevention of secondary contamination from metal-leaching

Facile Synthesis of Gd-Functionalized Gold Nanoclusters as Potential MRI/CT Contrast Agents

Multi-modal imaging plays a key role in the earlier detection of disease. In this work, a facile bioinspired method was developed to synthesize Gd-functionalized gold nanoclusters (Gd-Au NCs). The Gd-Au NCs exhibit a uniform size, with an average size of 5.6 nm in dynamic light scattering (DLS), which is a bit bigger than gold clusters (3.74 nm, DLS), while the fluorescent properties of Gd-Au NCs are almost the same as that of Au NCs. Moreover, the Gd-Au NCs exhibit a high longitudinal relaxivity value (r1) of 22.111 s−1 per mM of Gd in phosphate-buffered saline (PBS), which is six times higher than that of commercial Magnevist (A complex of gadolinium with a chelating agent, diethylenetriamine penta-acetic acid, Gd-DTPA, r1 = 3.56 mM−1·s−1). Besides, as evaluated by nano single photon emission computed tomography (SPECT) and computed tomography (CT) the Gd-Au NCs have a potential application as CT contrast agents because of the Au element. Finally, the Gd-Au NCs show little cytotoxicity, even when the Au concentration is up to 250 μM. Thus, the Gd-Au NCs can act as multi-modal imaging contrast agents

Global Action on SDGs: Policy Review and Outlook in a Post-Pandemic Era

The 2030 Agenda for Sustainable Development provided brand new goals and action targets for human well-being and development, but the COVID-19 pandemic has cast a shadow on the implementation of the Sustainable Development Goals (SDGs). It is therefore essential to provide a reference for making policy adjustments and transformations to promote the realization of SDGs in the post-pandemic era. Based on a literature review of the progress and policies of SDGs across countries worldwide, we find that research on sustainable policies has rapidly increased since the SDGs issued in 2015 with particular focuses on eco-environment, sustainable policies, green economy, sanitation and health, and water sanitation. Most countries are in the process of nationalization, institutionalization, and universalization of the SDGs through incorporating the SDGs into national development frameworks, enabling extensive participation and negotiation mechanisms, and promoting the SDGs’ national publicity. Countries of different economic and institutional backgrounds demonstrate divergent development pathways, priorities, measures, and progress in the implementation of SDGs. Despite significant global progress during the last five years, the North–South divide emerges in the policy action and achievement of SDGs. The least developed countries in sub-Sahara Africa and South Asia appear to be difficult or even unable to implement the SDGs and monitor the progress. In the post-pandemic era, particular attention shall be given to integrating SDGs and achieve synergy among goals, concretizing short-and medium-term priorities toward the SDGs targets for all countries, strengthening multilateralism and global cooperation among countries and continents, providing reliable data and approaches for real-time impact assessment and process monitoring, and promoting an inclusive engagement and integrative implementation with multiple stakeholders and consortiums

Modulating oxone-MnO<inf>x</inf>/silica catalytic systems towards ibuprofen degradation: Insights into system effects, reaction kinetics and mechanisms

© 2016 Elsevier B.V.Heterogeneous processes activated persulfate for organic degradation is increasingly recognized as an environmentally important remediation technology. However, manipulating persulfate oxidation processes with desirable decontamination effectiveness is still underdeveloped. Towards this goal, we systematically investigated the catalytic behaviors of Oxone-MnOx/silica systems towards aqueous ibuprofen (IBU) degradation in terms of system effects, reaction kinetics and mechanisms. MnOx/SBA-15 (MS) demonstrated variable catalytic Oxone efficacies towards IBU removal at different solution pHs. Meanwhile, the catalyst supports and FeOx co-doping within MS also produced significant impacts on catalytic Oxone efficacy. Moreover, the catalytic Oxone efficacies of MS for IBU degradation were generally inhibited by humic acid, NO3-, HCO3-, SO42- and PO43- to different extents at low/high levels. Interestingly, Cl- at low concentrations (2 mM) obviously inhibited IBU removal by Oxone-MS, while Cl- at high concentrations (20 mM) greatly enhanced IBU removal. Kinetic studies implied that IBU removal by Oxone-MnOx/silica systems using two first-order kinetic models was closely related to the extents of the interferences of synthetic conditions and water chemistry components. The surface electron transfer between [tbnd]MnOx(OH)y species of MS and HSO5- of Oxone was responsible for the formation of reactive oxygen radicals, thus contributing to IBU degradation. Liquid chromatography–mass spectrometry was employed to identify oxidation products of IBU, and reaction pathways of IBU oxidation were accordingly proposed

Transcriptome Analysis of Cyclooctasulfur Oxidation and Reduction by the Neutrophilic Chemolithoautotrophic Sulfurovum indicum from Deep-Sea Hydrothermal Ecosystems

Chemolithoautotrophic Campylobacterota are widespread and predominant in worldwide hydrothermal vents, and they are key players in the turnover of zero-valence sulfur. However, at present, the mechanism of cyclooctasulfur activation and catabolism in Campylobacterota bacteria is not clearly understood. Here, we investigated these processes in a hydrothermal vent isolate named Sulfurovum indicum ST-419. A transcriptome analysis revealed that multiple genes related to biofilm formation were highly expressed during both sulfur oxidation and reduction. Additionally, biofilms containing cells and EPS coated on sulfur particles were observed by SEM, suggesting that biofilm formation may be involved in S0 activation in Sulfurovum species. Meanwhile, several genes encoding the outer membrane proteins of OprD family were also highly expressed, and among them, gene IMZ28_RS00565 exhibited significantly high expressions by 2.53- and 7.63-fold changes under both conditions, respectively, which may play a role in sulfur uptake. However, other mechanisms could be involved in sulfur activation and uptake, as experiments with dialysis bags showed that direct contact between cells and sulfur particles was not mandatory for sulfur reduction activity, whereas cell growth via sulfur oxidation did require direct contact. This indirect reaction could be ascribed to the role of H2S and/or other thiol-containing compounds, such as cysteine and GSH, which could be produced in the culture medium during sulfur reduction. In the periplasm, the sulfur-oxidation-multienzyme complexes soxABXY1Z1 and soxCDY2Z2 are likely responsible for thiosulfate oxidation and S0 oxidation, respectively. In addition, among the four psr gene clusters encoding polysulfide reductases, only psrA3B3C3 was significantly upregulated under the sulfur reduction condition, implying its essential role in sulfur reduction. These results expand our understanding of the interactions of Campylobacterota with the zero-valence sulfur and their adaptability to deep-sea hydrothermal environments

High Levels of KAP1 Expression Are Associated with Aggressive Clinical Features in Ovarian Cancer

KAP1 is an universal corepressor for Kruppel-associated box zinc finger proteins in both normal and tumor cells. In this study, the biological function and clinical significance of KAP1 expression in ovarian cancer were investigated. Immunohistological staining of KAP1 was evaluated in 111 patients with ovarian epithelial cancer, 15 with ovarian borderline tumor, and 20 normal ovarian tissue. The correlations of KAP1 expression with clinicopathological features were studied. Kaplan-Meier analysis and Cox proportional hazard modeling were used to assess overall survival to analyze the effect of KAP1 expression on the prognosis of ovarian cancer. The positive rates of KAP1 were significantly higher in ovarian epithelial cancer (55.7%) and borderline tumor (20.0%) than in normal ovarian tissue (5.0%) (all p &lt; 0.01). KAP1 expression correlated significantly with clinical stage (χ2 = 14.57, p &lt; 0.0001), pathological grade (χ2 = 6.06, p = 0.048) and metastases (χ2 =10.38, p = 0.001). Patients with high KAP 1 levels showed poor survival (p &lt; 0.0001). Multivariate analysis showed that KAP1 high expression was an independent predictor for ovarian cancer patients (hazard ratio = 0.463; 95% confidence interval = 0.230–0.9318, p = 0.031). Functionally, depletion of KAP1 by siRNA inhibited ovarian cancer cell proliferation, cell migration. KAP1 expression correlated with aggressive clinical features in ovarian cancer. High KAP1 expression was a prognostic factor of ovarian cancer

Magnetic nitrogen-doped nanocarbons for enhanced metal-free catalytic oxidation: Integrated experimental and theoretical investigations for mechanism and application

© 2018 Elsevier B.V. Developing efficient, low-cost and environmental-friendly catalysts is of great significance for heterogeneous activation of persulfates toward strategic purification of wastewater with powerful sulfate radical based advanced oxidation processes (SR-AOPs). In this study, a three-dimensional and hierarchical nitrogen-doped magnetic carbon (Co@N-C) was developed via a facile one-pot carbonization of ZIF-67 with a green precursor of urea. Acid treatment was applied to remove the surface unstable cobalt nanoparticles (NPs) to avoid the potential leaching of toxic Co ions. Benefited from the rationally structural design of the carbon precursor and post-treatment with surface engineering, the derived Co@N-C can efficiently activate PMS for fast decomposition of bisphenol A (BPA) in aqueous solution, achieving high removal of total organic carbon (TOC) with trace cobalt leaching. The impacts of diverse reaction parameters on BPA degradation were systematically investigated. More importantly, density functional theory (DFT) calculations revealed that the entrapped Co NPs can impressively modulate the electronic states of the interacted carbon regions, giving rise to enhanced carbocatalysis with synergistic promotion of N-doping. The embedded Co NPs also afford the carbocatalysts to be magnetic for an easy recycling. Additionally, comprehensive investigations of the evolution of reactive oxygen species (ROS) on the carbonaceous materials by competitive radical scavenging tests and in situ radical trapping with advanced electron paramagnetic resonance (EPR) revealed the singlet oxygen (1O2) as the dominant ROS rather than sulfate radicals. This study proposed a facile strategy for fabricating novel hybrid nanocarbon catalysts with N-doping and magnetic property and enables new mechanistic insights into carbocatalysis in AOPs, providing a promising system for green wastewater remediation