Insight into the characterization of dissolved organic matter in shallow lakes with different trophic states and their net photo-generation capacity of reactive oxygen species.

Reactive oxygen species (ROS) are ubiquitous in the aquatic environment, and they are closely related to several biogeochemical processes. Dissolved organic matter (DOM) is one of the main photosensitizers involved in the formation of ROS and it also serves as a sink for ROS by involving in scavenging, quenching, and antioxidant reactions. The net effect of these processes depends on the concentration, source, and composition of the DOM.

Community-driven partnerships with Community-Engaged Research teams bring resources and reliable information to Baltimore residents.

This case study presents an analysis of community-driven partnerships, focusing on the nonprofit Baltimore CONNECT (BC) network and its collaborative efforts with a Community-Engaged Research (CEnR) team of the Johns Hopkins Institute for Clinical and Translational Research (ICTR). BC has built a network of over 30 community-based organizations to provide health and social services in Baltimore City. The study emphasizes the role of CEnR in supporting community-led decision-making, specifically in the planning and implementation of community health resource fairs.

Molecular-scale investigation on the photochemical transformation of dissolved organic matter after immobilization by iron minerals with FT-ICR MS.

The interaction between dissolved organic matter (DOM) and iron minerals has a significant effect on its stabilization and preservation in the environment. In this study, iron minerals with different crystal forms (crystalline goethite and amorphous ferrihydrite) were selected to investigate the photochemical transformation process for DOM immobilized on iron minerals under simulated sunlight irradiation at the molecular scale with the help of Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results showed that a total of 7148 molecules were detected in alkaline-extractable sedimentary DOM, of which 38.

Molecular characterization on the fractionation of organic phosphorus induced by iron oxide adsorption using ESI-FT-ICR MS.

The interaction between organic phosphorus (OP) and iron oxide significantly influences the phosphorus cycle in the natural environment. In shallow lakes, intense oxidation-reduction fluctuations constantly alter the existing form of iron oxides, but little is known about their impact on the adsorption and fractionation of OP molecules. In this study, electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS) was used to investigate the fractionation of OP from alkali-extracted sediment induced by crystalline goethite and amorphous ferrihydrite adsorption at a molecular scale.

Sources and hydrogeochemical processes of groundwater under multiple water source recharge condition.

Ecological water replenishment (EWR) is an essential approach for improving the quantity and quality of regional water. The Chaobai River is a major river in Beijing that is replenished with water from multiple sources, including reclaimed water (RW), the South-North Water Transfer Project (SNTP), reservoir discharge (RD). The effects of multiple water source recharge (MWSR) on groundwater quality remain unclear.

New insights into the mechanism of phosphate release during particulate organic matter photodegradation based on optical and molecular signatures.

Phosphate release from particulate organic matter (POM) dominates phosphorus (P) cycling in aquatic ecosystems. However, the mechanisms underlying P release from POM remain poorly understood because of complex fractionation and analytical challenges. In this study, the release of dissolved inorganic phosphate (DIP) during POM photodegradation was assessed using excitation-emission matrix (EEM) fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS).

Hydrochemical evolution characteristics and genesis of groundwater under long-term infiltration (2007-2018) of reclaimed water in Chaobai River, Beijing.

The reuse of reclaimed water (RW) for river ecological restoration in global water-shortage regions has inevitably brought some potential risks for groundwater. However, little is known about the effects of reclaimed water on the hydrochemical evolution of groundwater especially under long-term infiltration conditions. Herein, 11-years monitoring data (2007-2018) of reclaimed water and groundwater were adopted to analyze the characteristics and genesis of groundwater hydrochemical evolution under long-term infiltration of reclaimed water from Jian River to Chaobai River in Beijing.

Molecular insight into the release of phosphate from dissolved organic phosphorus photo-mineralization in shallow lakes based on FT-ICR MS analysis.

Dissolved organic phosphorus (DOP) is a key factor in the water eutrophication process because of its high potential bioavailability and inorganic phosphate (Pi) compensation ability through bio- and photo-mineralization. However, the research on the characterization and transformation of DOP is insufficient owing to their complex composition. This study investigates the release of dissolved Pi from DOP photo-mineralization in Lake Dong based on Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis.

Multiple optimizations of recombinant plasmid for improving expression of Hepatitis B core antigen in Escherichia coli.

Hepatitis B core antigen (HBcAg) can self-assemble into virus-like particles (VLPs) when expressed in Escherichia coli. We optimized the different of the expression plasmid pBV220, including the ribosome bind site (RBS), spacer region, promoter and replication origin (ori), as well as the hbc gene dosage, to enhance HBcAg transcription and translation in E. coli.

Photo-induced phosphate release during sediment resuspension in shallow lakes: A potential positive feedback mechanism of eutrophication.

Dissolved phosphate (P) can be released during resuspended sediments exposed to sunlight. However, the significance of this phenomenon in the process of eutrophication is not clear. In this study, the behavior of photo-induced P release during sediment resuspension in shallow lakes with the different trophic states was investigated.

Distribution of organic phosphorus species in sediment profiles of shallow lakes and its effect on photo-release of phosphate during sediment resuspension.

In this work, the distribution of organic phosphorus (P) species in sediment profiles of five shallow lakes was analyzed and its effect on the photo-release of dissolved phosphate (P) was investigated during sediment resuspension under simulated sunlight irradiation. The results show that P was highly enriched in the surface sediment and gradually decreased as sediment depths increased: 33.10 ± 2.

[Comparison of migration characteristic of 3H and 99Tc in loess].

3H and 99Tc are important nuclides in low and intermediate level radioactive wastes, and in safety assessment of near surface repository their migration characteristic usually determines the computing result. The medium of loess appears to possess the characteristic of weak adsorption ability to 3H and 99Tc when they are migrating in it, so the adsorption ability are often neglected, and 3H are used to identify groundwater velocity. But in the field test it was showed that in the aerated zone loess possesses stronger adsorption ability to 99Tc than to 3H, and in the aquifer the stronger adsorption ability to 3H than to 99Tc.