A novel method for production of nitrogen fertilizer with low energy consumption by efficiently adsorbing and separating waste ammonia.

Recovering waste NH3 to be used as a source of nitrogen fertilizer or liquid fuel has recently attracted much attention. Current methods mainly utilize activated carbon or metal-organic frameworks to capture NH3, but are limited due to low NH3 adsorption capacity and high cost, respectively. In this study, novel porous materials that are low cost and easy to synthesize were prepared as NH3 adsorbents by precipitation polymerization with acid optimization. The results showed that adsorption sites (‒COOH, -OH, and lactone) which form chemical adsorption or hydrogen bonds with NH3 were successfully regulated by response surface methods. Correspondingly, the dynamic NH3 adsorption capacity increased from 5.45 mg g-1 to 129 mg g-1, which is higher than most known activated carbon and metal-organic frameworks. Separation performance tests showed that NH3 could also be separated from CO2 and CH4. The findings in this study will advance the industrialization of NH3 polymer adsorbents and provide technical support for the recycling of waste NH3.

Endocytosis-Mediated Transport of Pb in Rat Blood Cells.

Blood is an important reservoir for Pb storage in living organisms, and the storage of Pb in blood cells inhibits its discharge from blood. However, the mechanism and molecular targets of Pb entry and exit from blood cells have not been elucidated, which is the major barrier to reducing blood Pb levels in normal human beings. In this study, we explored the effect of Pb-binding proteins on blood Pb levels in rats at environmentally relevant concentrations (0.32 µg/g) by identifying the functions of Pb-binding proteins and validating them with inhibitors. The results showed that Pb-binding proteins in blood cells were mainly related to phagocytosis, while in plasma, they were mainly involved in the regulation of endopeptidase activity. Meanwhile, at the normal population Pb levels, endocytosis inhibitors, endopeptidase activity inhibitors, and coadministration of both can reduce the level of Pb in MEL (mouse erythroleukemia cells) cells by up to 50, 40, and 50%, respectively, while in rat blood, the reduction can reach up to 26, 13, and 32%, respectively. Collectively, these findings reveal that endocytosis increases blood Pb levels and provides a possible molecular target for Pb excretion at ambient concentrations.

Chemical Nature of Metals and Metal-Based Materials in Inactivation of Viruses.

In response to the enormous threat to human survival and development caused by the large number of viruses, it is necessary to strengthen the defense against and elimination of viruses. Metallic materials have been used against viruses for thousands of years due to their broad-spectrum antiviral properties, wide sources and excellent physicochemical properties; in particular, metal nanoparticles have advanced biomedical research. However, researchers in different fields hold dissimilar views on the antiviral mechanisms, which has slowed down the antiviral application of metal nanoparticles. As such, this review begins with an exhaustive compilation of previously published work on the antiviral capacity of metal nanoparticles and other materials. Afterwards, the discussion is centered on the antiviral mechanisms of metal nanoparticles at the biological and physicochemical levels. Emphasis is placed on the fact that the strong reducibility of metal nanoparticles may be the main reason for their efficient inactivation of viruses. We hope that this review will benefit the promotion of metal nanoparticles in the antiviral field and expedite the construction of a barrier between humans and viruses.

Ethylene dimethacrylate used as an NH3 adsorbent with high adsorption capacity and selectivity.

NH3 molecularly imprinted polymers (NH3-MIPs) were synthesized that could successfully separate and recover NH3 during sludge aerobic composting; however, increased toluene usage during the adsorbent preparation incurred a high cost and severe environmental risks. The purpose of this study was to reduce toluene usage by optimizing the reagent composition of NH3-MIPs, based on maintaining a high NH3 adsorption capacity and selectivity. Five adsorbent groups, including NH3-MIPs, and NH3-Ethylene dimethacrylate adsorbents (NH3-EGDMA) with 0%, 75%, 90%, and 100% toluene reduction efficiencies, were prepared and tested for their adsorption performance. The results showed that NH3-EGDMA with 75% toluene reduction not only had a high NH3 adsorption capacity (104.42 mg g-1) but also had a high separation factor for NH3/methyl sulfide (3121) and NH3/dimethyl disulfide (4597). The adsorption mechanism was identified as a chemical force between NH3 and NH3-EGDMA with a 75% toluene reduction using the analysis of the kinetic model. This study significantly reduces NH3 adsorbent cost as well as harm to the environment during the adsorbent preparation, which was beneficial to the popularization and application of this NH3 adsorbent.

Enhanced ammonia adsorption and separation by a molecularly imprinted polymer after acid hydrolysis of its ester crosslinker.

While ammonia (NH3) is one of the primary hazardous emissions from sludge aerobic composting plants, it has the potential to be recycled as an energy source or nitrogen fertilizer. Recently, an NH3 molecularly imprinted polymer (NH3-MIP) was developed that efficiently separated NH3 from other compounds, but its adsorption capacity required improvement. This study improved both NH3 adsorption capacity and separation of the NH3-MIP using acid hydrolysis optimization. NH3 adsorption capacity increased 13-fold and remained between 5.59 and 7.84 mmol·g-1 during simulated sludge aerobic composting. Separation factors for NH3/methyl sulfide (DMS) (i.e. NH3 adsorption capacity/DMS adsorption capacity) and NH3/dimethyl disulfide both increased more than 15-fold. Results showed that hydrolysis of the ester crosslinker, ethylene glycol dimethacrylate, on the NH3-MIPs produced chemical adsorption sites (‒COOH and epoxides) and increased hydrogen bonds (‒COOH and alcohol hydroxyl), which promoted NH3 adsorption and separation. It is expected that this will be a beneficial strategy for elimination of odors and NH3 recovery during sludge aerobic composting.

Synthesis of ammonia molecularly imprinted adsorbents and ammonia adsorption separation during sludge aerobic composting.

Ammonia (NH3) is the predominant harmful odor emitted from sludge aerobic composting plants, however, this NH3 could be recycled and used as energy or nitrogen fertilizer. Therefore, the aim of this study was to use molecular imprinting technology to prepare an adsorbent that could separate NH3 from mixed gases. An NH3 molecular imprinted polymer (NH3-MIP) was prepared by precipitation polymerization and optimal synthesis was determined by testing several different ratios of reaction components. NH3 adsorption capacity of the optimal NH3-MIP was 1.62 times that of non-imprinted material. NH3 separation factors increased from 154 (dimethyl sulfides) and 217 (dimethyl disulfides) for non-imprinted material, to 213 (dimethyl sulfides) and 302 (dimethyl disulfides) for the NH3-MIP. The adsorption mechanism was identified as physical adsorption and hydrogen bonding between H-O on the -COOH in NH3-MIP and the nitrogen in NH3. Effective desorption at 150 °C with vacuum maintained over 95% of the NH3 adsorption capacity.

Enhancing biotreatment of incineration leachate by applying an electric potential in a partial nitritation-Anammox system.

An electric potential (EP) was applied to enhance biotreatment of anaerobically-treated leachate from municipal solid waste incineration plants using a partial nitritation-Anammox system. At an optimal EP difference of 0.06 V, total nitrogen removal efficiency reached 71.9%, 17.3% higher than the control system without an EP. Removal of organic matter was also stimulated with the EP, particularly macromolecules with molecular weight >20 kDa in the leachate. Applying EP also promoted production of extracellular polymeric substances and improved the protein/polysaccharide ratio. High-throughput DNA sequencing revealed that Anammox bacteria in the genus Candidatus Kuenenia were enriched for on electrodes with the applied EP. Heterotrophic denitrifiers, which potentially could degrade organic macromolecules, were also more abundant on the electrodes with EP compared with the control reactor. These results show that applying an EP could be a useful strategy in Anammox technologies treating real wastewater high in ammonia and refractory organic compounds.

Design, synthesis and structure-activity relationship of diaryl-ureas with novel isoxazol[3,4-b]pyridine-3-amino-structure as multi-target inhibitors against receptor tyrosine kinase.

Inspired by that the multi-target inhibitors against receptor tyrosine kinases (RTKs) have significantly improved the effect of clinical treatment for cancer, and based on the chemical structure of Linifanib (ABT-869, Abbott), two series of diaryl-ureas with novel isoxazol[3,4-b]pyridine-3-amino-structure were designed and synthesized as multi-target inhibitors against RTKs. The preliminary biological evaluation showed that several compounds exhibited comparable potency with Linifanib. Compound S21 was identified as the most potent inhibitor against Fms-like tyrosine kinase 3 (FLT-3), kinase insert domain containing receptor (KDR) and platelet-derived growth factor receptor ß (PDGFR-ß) with its IC50 values were 4 nM, 3 nM and 8 nM respectively, it also showed potent inhibitory activities against several cancer cells.

Identification of Covalent Binding Sites Targeting Cysteines Based on Computational Approaches.

Covalent drugs have attracted increasing attention in recent years due to good inhibitory activity and selectivity. Targeting noncatalytic cysteines with irreversible inhibitors is a powerful approach for enhancing pharmacological potency and selectivity because cysteines can form covalent bonds with inhibitors through their nucleophilic thiol groups. However, most human kinases have multiple noncatalytic cysteines within the active site; to accurately predict which cysteine is most likely to form covalent bonds is of great importance but remains a challenge when designing irreversible inhibitors. In this work, FTMap was first applied to check its ability in predicting covalent binding site defined as the region where covalent bonds are formed between cysteines and irreversible inhibitors. Results show that it has excellent performance in detecting the hot spots within the binding pocket, and its hydrogen bond interaction frequency analysis could give us some interesting instructions for identification of covalent binding cysteines. Furthermore, we proposed a simple but useful covalent fragment probing approach and showed that it successfully predicted the covalent binding site of seven targets. By adopting a distance-based method, we observed that the closer the nucleophiles of covalent warheads are to the thiol group of a cysteine, the higher the possibility that a cysteine is prone to form a covalent bond. We believe that the combination of FTMap and our distance-based covalent fragment probing method can become a useful tool in detecting the covalent binding site of these targets.