Engineering最新文献

In the microalgae harvesting process, which includes a step for dewatering the algal suspension, directly reusing extracted water in situ would decrease the freshwater footprint of cultivation systems. Among various algae harvesting techniques, membrane-based filtration has shown numerous advantages. This study evaluated the reuse of permeate streams derived from Scenedesmus obliquus (S. obliquus) biomass filtration under bench-scale and pilot-scale conditions. In particular, this study identified a series of challenges and mechanisms that influence the water reuse potential and the robustness of the membrane harvesting system. In a preliminary phase of this investigation, the health status of the initial biomass was found to have important implications for the harvesting performance and quality of the permeate stream to be reused; healthy biomass ensured better dewatering performance (i.e., higher water fluxes) and higher quality of the permeate water streams. A series of bench-scale filtration experiments with different combinations of cross-flow velocity and pressure values were performed to identify the operative conditions that would maximize water productivity. The selected conditions, 2.4 m·s⁻¹ and 1.4 bar (1 bar = 10⁵ Pa), respectively, were then applied to drive pilot-scale microfiltration tests to reuse the collected permeate as a new cultivation medium for S. obliquus growth in a pilot-scale photobioreactor. The investigation revealed key differences between the behavior of the membrane systems at the two scales (bench and pilot). It indicated the potential for beneficial reuse of the permeate stream as the pilot-scale experiments ensured high harvesting performance and growth rates of biomass in permeate water that were highly similar to those recorded in the ideal cultivation medium. Finally, different nutrient reintegration protocols were investigated, revealing that both macro- and micro-nutrient levels are critical for the success of the reuse approach.

This work explores the potential of a triple combination of meropenem (MEM), a novel metallo-β-lactamase (MBL) inhibitor (indole-2-carboxylate 58 (InC58)), and a serine-β-lactamase (SBL) inhibitor (avibactam (AVI)) for broad-spectrum activity against carbapenemase-producing bacteria. A diverse panel comprising MBL- and SBL-producing strains was used for susceptibility testing of the triple combination using the agar dilution method. The frequency of resistance (FoR) to MEM combined with InC58 was investigated. Mutants were sequenced and tested for cross resistance, fitness, and the stability of the resistance phenotype. Compared with the double combinations of MEM plus an SBL or MBL inhibitor, the triple combination extended the spectrum of activity to most of the isolates bearing SBLs (oxacillinase-48 (OXA-48) and Klebsiella pneumoniae carbapenemase-2 (KPC-2)) and MBLs (New Delhi metallo-β-lactamases (NDMs)), although it was not effective against Verona integron-encoded metallo-β-lactamase (VIM)-carrying Pseudomonas aeruginosa (P. aeruginosa) and OXA-23-carrying Acinetobacter baumannii (A. baumannii). The FoR to MEM plus InC58 ranged from 2.22 × 10⁻⁷ to 1.13 × 10⁻⁶. The resistance correlated with mutations to ompC and comR, affecting porin C and copper permeability, respectively. The mutants manifested a fitness cost, a decreased level of resistance during passage without antibiotic pressure, and cross resistance to another carbapenem (imipenem) and a β-lactamase inhibitor (taniborbactam). In conclusion, compared with the dual combinations, the triple combination of MEM with InC58 and AVI showed a much wider spectrum of activity against different carbapenemase-producing bacteria, revealing a new strategy to combat β-lactamase-mediated antimicrobial resistance.

The Advanced Geosynchronous Radiation Imager (AGRI) is a mission-critical instrument for the Fengyun series of satellites. AGRI acquires full-disk images every 15 min and views East Asia every 5 min through 14 spectral bands, enabling the detection of highly variable aerosol optical depth (AOD). Quantitative retrieval of AOD has hitherto been challenging, especially over land. In this study, an AOD retrieval algorithm is proposed that combines deep learning and transfer learning. The algorithm uses core concepts from both the Dark Target (DT) and Deep Blue (DB) algorithms to select features for the machine-learning (ML) algorithm, allowing for AOD retrieval at 550 nm over both dark and bright surfaces. The algorithm consists of two steps: ① A baseline deep neural network (DNN) with skip connections is developed using 10 min Advanced Himawari Imager (AHI) AODs as the target variable, and ② sunphotometer AODs from 89 ground-based stations are used to fine-tune the DNN parameters. Out-of-station validation shows that the retrieved AOD attains high accuracy, characterized by a coefficient of determination (R²) of 0.70, a mean bias error (MBE) of 0.03, and a percentage of data within the expected error (EE) of 70.7%. A sensitivity study reveals that the top-of-atmosphere reflectance at 650 and 470 nm, as well as the surface reflectance at 650 nm, are the two largest sources of uncertainty impacting the retrieval. In a case study of monitoring an extreme aerosol event, the AGRI AOD is found to be able to capture the detailed temporal evolution of the event. This work demonstrates the superiority of the transfer-learning technique in satellite AOD retrievals and the applicability of the retrieved AGRI AOD in monitoring extreme pollution events.

Four new norditerpenoid heterodimers with different dimerization patterns—namely, trigofragiloids A–C (denoted as compounds 1–3) and (+)- and (−)-trigofragiloid D (compound 4)—and three new phenanthrenone norditerpenoids—namely, trigofragiloids E–G (compounds 5–7)—were isolated from Trigonostemon fragilis. Compounds 1 and 2 feature a novel heterodimeric carbon skeleton formed by the conjugation of a tetra-norditerpenoid and an ennea-norditerpenoid; they have been identified as class 2 atropisomers by means of quantum chemical calculations. Compound 3 is an unprecedented phenylpropanoid–norditerpenoid adduct with a new dimerization pattern. Compounds (+)- and (−)-4 are the first example of S-shaped 1,4-dioxane-fused norditerpenoid dimers. Inspired by the structure elucidation of compound 4, two co-occurring analogues, actephilol A and epiactephilol A, were structurally revised as a pair of geometrical isomers and were identified as two pairs of enantiomers, (+)- and (−)-8 and (+)- and (−)-9, respectively. Their structures were characterized using a combined method. Notably, compound 7 exhibits remarkable adenosine triphosphate-citrate lyase (ACLY) inhibition with a half-maximal inhibition concentration (IC₅₀) value of (0.46 ± 0.11) μmol∙L⁻¹, as active as the positive control BMS-303141, and a molecular docking study offers deep insight into the interaction between compound 7 and ACLY.

Antibacterial resistance is a global health threat that requires further concrete action on the part of all countries. In this context, one of the biggest concerns is whether enough new antibacterial drugs are being discovered and developed. Although several high-quality reviews on clinical antibacterial drug pipelines from a global perspective were published recently, none provides comprehensive information on original antibacterial drugs at clinical stages in China. In this review, we summarize the latest progress of novel antibacterial drugs approved for marketing and under clinical evaluation in China since 2019. Information was obtained by consulting official websites, searching commercial databases, retrieving literature, asking personnel from institutions or companies, and other means, and a considerable part of the data covered here has not been included in other reviews. As of June 30, 2023, a total of 20 antibacterial projects from 17 Chinese pharmaceutical companies or developers were identified and updated. Among them, two new antibacterial drugs that belong to traditional antibiotic classes were approved by the National Medical Products Administration (NMPA) in China in 2019 and 2021, respectively, and 18 antibacterial agents are in clinical development, with one under regulatory evaluation, five in phase-3, six in phase-2, and six in phase-1. Most of the clinical candidates are new analogs or mono-components of traditional antibacterial pharmacophore types, including two dual-acting hybrid antibiotics and a recombinant antibacterial protein. Overall, despite there being 17 antibacterial clinical candidates, our analysis indicates that there are still relatively few clinically differentiated antibacterial agents in stages of clinical development in China. Hopefully, Chinese pharmaceutical companies and institutions will develop more innovative and clinically differentiated candidates with good market potential in the future research and development (R&D) of original antibacterial drugs.

Microcirculatory disturbances are complex processes caused by many factors, including abnormal vasomotor responses, decreased blood flow velocity, vascular endothelial cell injury, altered leukocyte and endothelial cell interactions, plasma albumin leakage, microvascular hemorrhage, and thrombosis. These disturbances involve multiple mechanisms and interactions among mechanisms that can include energy metabolism, the mitochondrial respiratory chain, oxidative stress, inflammatory factors, adhesion molecules, the cytoskeleton, vascular endothelial cells, caveolae, cell junctions, the vascular basement membrane, neutrophils, monocytes, and platelets. In clinical practice, aside from drugs that target abnormal vasomotor responses and platelet adhesion, there continues to be a lack of multi-target drugs that can regulate the complex mechanistic links and interactions underlying microcirculatory disturbances. Natural products have demonstrated obvious positive therapeutic effects in treating ischemia/reperfusion (I/R)- and lipopolysaccharide (LPS)-induced microcirculatory disturbances. In recent years, numerous research papers on the improvement of microcirculatory function by natural products have been published in international journals. In 2008 and 2017, the first listed author of this review was invited to publish reviews in the journal of Pharmacology & Therapeutics on the improvement of microcirculatory disturbances and organ injury induced by I/R using Salvia miltiorrhiza ingredients and other natural components of compounded Chinese medicine, respectively. This review systematically summarizes the effects, targets of action, and mechanisms of natural products regarding improving I/R- and LPS-induced microcirculatory disturbances and tissue injury. Based on this summary, scientific proposals are suggested for the discovery of new drugs to improve microcirculatory disturbances in disease.

The availability of nitrogen (N) is crucial for both the productivity of terrestrial and aquatic ecosystems globally. However, the overuse of artificial fertilizers and the energy required to fix nitrogen have pushed the global nitrogen cycle (N-cycle) past its safe operating limits, leading to severe nitrogen pollution and the production of significant amounts of greenhouse gas nitrous oxide (N₂O). The anaerobic ammonium oxidation (anammox) mechanism can counteract the release of ammonium and N₂O in many oxygen-limited situations, assisting in the restoration of the homeostasis of the Earth’s N biogeochemistry. In this work, we looked into the characteristics of the anammox hotspots’ distribution across various types of ecosystems worldwide. Anammox hotspots are present at diverse oxic–anoxic interfaces in terrestrial systems, and they are most prevalent at the oxic–anoxic transition zone in aquatic ecosystems. Based on the discovery of an anammox hotspot capable of oxidizing ammonium anoxically into N₂ without N₂O by-product, we then designed an innovative concept and technical routes of nature-based anammox hotspot geoengineering for climate change, biodiversity loss, and efficient utilization of water resources. After 15 years of actual use, anammox hotspot geoengineering has proven to be effective in ensuring clean drinking water, regulating the climate, fostering plant and animal diversity, and enhancing long-term environmental quality. The sustainable biogeoengineering of anammox could be a workable natural remedy to resolve the conflicts between environmental pollution and food security connected to N management.