Search

Abstract The condition of Baiyangdian Lake (BYDL) will improve as the Xiongan New Area evolves and fulfills its role of easing overcrowding and supporting economic growth. Water and sediment samples from BYDL were analyzed to provide information on nitrogen (N) contamination in BYDL. The mean ammonium N (NH 4 +-N), nitrate N, and total N concentrations in the water samples were 0.36, 0.12, and 2.22 mg/L, respectively, and the ranges were 0.003–8.38, 0.06–0.30, and 1.25–10.34 mg/L, respectively. The N concentrations in water gradually increased from the north to the south of BYDL. Sediment at 90% of the sampling sites was in or above the moderately contaminated class (1000–2000 mg/kg) defined in US Environmental Protection Agency total N pollution standards. Positive NH 4 +-N fluxes were found for 28 of the 34 sediment core samples, so the potential for NH 4 +-N being released from sediment was relatively high. The NH 4 +-N fluxes were 5.35–48.76 mg/m2/day, and the mean and maximum fluxes were 8.71 and 48.76 mg/m2/day, respectively. Benthic organisms will be affected more by NH 4 +-N and NH 3 ·H 2 O in the surface sediment pore water (mean concentrations 4.93 and 0.13 mg/L, respectively) than by the other forms of N. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract The effects of reduced nitrogen release from sediments were studied using biochar (BC) capping in simulated water–sediment systems. Dried solid waste of Phyllostachys pubescens was used to produce BC, which was then pyrolyzed at 500 °C. Subsequently, 14 sediment cores were collected, including the sediment–water interface and some overlying water, from two sites in Baiyangdian Lake (China). The sediment cores were split into two batches (A and B), and then two each were capped with soil, BC or a BC/soil mixture, and incubated for 30 days. In the BC capped cores, the ammonia nitrogen (NH 4 +-N), nitrate nitrogen (NO 3 −-N) and total nitrogen (TN) concentrations decreased from 0.90 mg·L−1 to 0.05 mg·L−1, 0.88 mg·L−1 to 0.18 mg·L−1, 6.93 mg·L−1 to 2.81 mg·L−1, respectively, in batch A and 3.51 mg·L−1 to 0.11 mg·L−1, 0.92 mg·L−1 to 0.61 mg·L−1, 8.88 mg·L−1 to 3.32 mg·L−1, respectively, in batch B. The sediments to water fluxes of NH 4 +-N, NO 3 −-N and TN were greatly reduced or reversed. Compared with other cappings, the BC layer was shown to absorb more NH 4 +-N from the pore water, thereby breaking the diffusion gradient of NH 4 +-N at the sediment–water interface, and has a good inhibitory effect on the endogenous release of NH 4 +-N from the sediments. Additionally, in the BC capped cores, the redox potential remarkably increased and dissolved oxygen was comparatively high. This study suggests that BC capping can reduce the amount of nitrogen released from polluted sediments because the diffusion of nitrogen to the overlying water is chemically blocked by the cap. Graphical abstract Unlabelled Image Highlights • This study investigates the use of solid waste of Phyllostachys pubescens. • We first propose the idea of using biochar for sediment nitrogen remediation. • Biochar has a good effect on reducing nitrogen release, especially NH 4 +-N. • We propose a good application of biochar capping technology. [ABSTRACT FROM AUTHOR]

Abstract Biochar has potential for application for in situ metal-contaminated sediment remediation, mainly because of its cost-effectiveness. In this study, the effectiveness of Phyllostachys pubescens (PP) biochar for immobilization of cadmium (Cd) chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) by decreasing the bioavailable fraction was investigated using a series of laboratory sediment remediation microcosms. The results demonstrated that biochar could significantly reduce the bioavailable fraction of metals (except for Cr) by diffusive gradients in thin film (DGT) measurement in porewater. Additionally, amended sediment treated with 15% w/w biochar resulted in 79.71%, 73.20%, 54.86%, 49.75%, 31.16% and 0.99% reductions in the acid-soluble fraction for Cu, Pb, Ni, Zn, Cd, and Cr, respectively. Similarly, bioaccumulation of metals (except for Cr) by Limnodrilus hoffmeisteri was reduced by 18.45%–59.15% in biochar amended sediment. PP biochar at 15% could also reduce the inhibition or lethality rate by 37.5%, 18.1% and 36.3% for Chlorella vulgaris , Daphnia magna and luminescent bacteria Vibrio qinghaiensis , respectively. Overall, these results demonstrate the potential for biochar application for in situ sediment remediation. Graphical abstract Image 1 Highlights • Biochar effectively reduced DGT-assessed bioavailable metals in sediment. • Metal bioaccumulation in Limnodrilus hoffmeisteri was significantly reduced. • Biochar could be a potential amendment material for metal-contaminated sediment. [ABSTRACT FROM AUTHOR]

• Hydrophobic modification PEO-PPO copolymer BP123 was synthesized, compared with P123. • Effect of NaCl, sodium citrate and sodium benzoate on aggregation were studied. • With NaCl or sodium citrate, CMC, micellar size and drug solubilization increased. • With sodium citrate, CMC decreased, drug release rate slowed. Hydrophobic modification PEO-PPO copolymer BP123 was synthesized, with two aromatic rings in the centre linked to PEO-PPO blocks, and the identical PEO and PPO block numbers were possessed with commercial copolymer P123. The influence of three common pharmaceutical excipient salts sodium chloride (NaCl), sodium citrate (NaCA) and sodium benzoate (NaBZ) on self-assembly behaviors of BP123 and P123 was investigated via cloud point, surface tension, pyrene fluorescence and dynamic light scattering. Solubilization for hydrophobic drug simvastatin (SV) and in vitro drug release behavior were assessed accordingly. In the presence of NaCl or NaCA, cloud point and critical micellization concentration (CMC) decreased, micelles became more hydrophobic, micellar size and drug solubilization increased, drug release rate slowed, and the impact of NaCA was more significant than NaCl. Oppositely, cloud point and CMC increased with the addition of NaBZ. NaBZ could participate in the formation of micelles by hydrophobic aromatic ring, which greatly raised solubilization of SV. Moreover, a different performance occurred when NaBZ was added to BP123 or P123, due to the hydrophobic benzene rings in BP123, which prominently enhanced the interaction with hydrophobic drug, leading to obvious delay of drug release for BP123. This work is conducive to turning copolymer property in diverse pharmaceutical applications and in drug delivery systems as drug carriers. [ABSTRACT FROM AUTHOR]

To investigate the characteristics of suspended particulate matter (SPM) in rivers of northern China, SPM was collected from 20 sampling sites within the severely polluted slow-moving Ziya River Mainstream (ZRM) and from 20 sampling sites within the less-polluted fast-moving Luanhe River (LR) between October and November of 2016. Physical and chemical attributes of river water from the ZRM and LR were measured; the microstructure, specific surface area and particle size of the SPM were also determined. The SPM had thicker organic coated layers on inorganic particles within the ZRM, compared with the LR, indicating strong interaction of the SPM with the water column. Along the ZRM length, these organic coated layers evolved, first plugging particle pores and then increasing in volume, causing the specific surface area to decrease at first and then increase. The presence of organic coated layers on inorganic particles greatly changed their particle size, density and inducing changes in their motion behavior. Such changes in SPM microstructure were most apparent in the slow-moving polluted ZRM. Given that SPM can adsorb contaminants, such as phosphorus and heavy metals, onto its surfaces and transport them downstream, these changes could have a profound impact on both sediment transport and river ecosystem function. Our results suggest we need to reevaluate our previous river management measures for slow-moving polluted rivers. [ABSTRACT FROM AUTHOR]

Human pluripotent stem cells (hPSCs) provide a powerful platform for studying the dynamic molecular network towards hematopoiesis. To date, a comprehensive roadmap at single-cell level for hPSC-derived hematopoietic differentiation has not been established. Here, we performed single-cell transcriptomic analyses to map gene expression programs during hematopoietic differentiation of hPSCs, from which new strategies to improve in vitro hematopoietic differentiation may be thus developed. We firstly established a serum-free, stroma-free and chemically defined monolayer system for hematopoietic differentiation of hPSCs, which enabled single-cell transcriptomic analysis. Through identifying sequential molecular events, we generated a time-course gene expression profile revealing the temporally restricted expression dynamics of stage-specific genes associated with hematopoietic cell fate choices. To better understand the lineage trajectories and gene regulatory networks governing diversification of cell fates, we established transcription factor regulatory networks predicting developmental fate choices during hematopoietic differentiation. By pseudotime analysis, we constructed the endothelial-hematopoietic trajectory revealing a novel hematopoietic development model that hemogenic endothelium initiated first and then differentiated into arteries and veins, whereas arteries had the ability to promote endothelial-to-hematopoietic transition. Moreover, we found that the genes related to aerobic metabolism were significantly decreased in hematopoietic cells and hypoxia-primed hematopoietic differentiation showed higher potency for generating more hematopoietic lineages. Further studies showed that hypoxia enhanced hematopoietic differentiation by promoting the development of arterial endothelium, rather than directly acting on hemogenic endothelium. [ABSTRACT FROM AUTHOR]

Phyllostachys pubescens (PP) biochars produced under a low oxygen pyrolysis atmosphere (oxygen content 1–4%) were prepared as sorbents for investigating the mechanisms of cadmium and lead sorption. A low-oxygen pyrolysis atmosphere increased biochar ash and specific surface area, promoting heavy metal precipitation and complexation. The maximum sorption capacity (Q m ) of Pb 2+ obtained from the Langmuir model was 67.4 mg·g −1 , while Q m of Cd 2+ was 14.7 mg·g −1 . The contribution of each mechanism varied with increasing oxygen content at a low pyrolysis temperature. Mineral precipitation with Pb 2+ was the predominant mechanism for Pb 2+ removal and the contribution proportion significantly increased from 17.2% to 71.7% as pyrolysis oxygen atmosphere increased from 0% to 4%. The results showed that cadmium sorption primarily involved coordination with π electrons, at 54.1–82.6% of the total adsorption capacity. The PP biochar shows potential for application in removing heavy metal contaminants, especially Pb 2+ . [ABSTRACT FROM AUTHOR]

While phosphorus (P) is a vital element in freshwater systems, excessive P loads will induce eutrophication. Large inputs of various pollutants, including P, to rivers in semi-arid regions result in complex environmental problems. In this study, we investigate dissolved oxygen (DO), ammoniacal nitrogen (NH 3 ), chemical oxygen demand (CODcr), soluble reactive P (SRP) in surface water and pore water, and sediment P in the Niuwei River, within the Hai River Basin. From our results we developed and tested a theory for P release in semi-arid regions driven by DO. The results show that NH 3 and CODcr can cause variations in DO in surface water. The presence of pollutants at high concentrations caused seasonal hypoxia. Hypoxic river water induced adsorption and hydrolysis of NaOH-Pi and labile organic P (L-Po), which then resulted in increased SRP concentrations in pore water and surface water. Overall, our results illustrate that NH 3 and CODcr may be important for P adsorption and desorption and for management of water quality problems in rivers in semi-arid regions. [ABSTRACT FROM AUTHOR]

Abstract: Nanoscale zero-valent iron (NZVI) supported on ordered mesoporous carbon (OMC) was synthesized through liquid phase reduction route. The NZVI/OMC composite was characterized by X-ray diffraction, N 2 adsorption/desorption and transmission electron microscopy. Results reveal that the composite possesses ordered mesostructure with NZVI distributing homogeneously on the surface of OMC support. The removal effects of nitrobenzene (NB) in water with OMC, NZVI/OMC and non-supported NZVI were evaluated. Results indicate that NZVI/OMC shows enhanced removal efficiency, which is attributed to its adsorption and synergistic reduction for NB. The transformation process of NB was further investigated by HPLC. Nitrosobenzene and phenylhydroxylamine were detected as intermediate products and aniline was the final reductive product. [Copyright &y& Elsevier]

Abstract: Segmentation is a fundamental component of many medical image-processing applications, and it has long been recognized as a challenging problem. In this paper, we report our research and development efforts on analyzing and extracting clinically meaningful regions from uterine cervix images in a large database created for the study of cervical cancer. In addition to proposing new algorithms, we also focus on developing open source tools which are in synchrony with the research objectives. These efforts have resulted in three Web-accessible tools which address three important and interrelated sub-topics in medical image segmentation, respectively: the Boundary Marking Tool (BMT), Cervigram Segmentation Tool (CST), and Multi-Observer Segmentation Evaluation System (MOSES). The BMT is for manual segmentation, typically to collect “ground truth” image regions from medical experts. The CST is for automatic segmentation, and MOSES is for segmentation evaluation. These tools are designed to be a unified set in which data can be conveniently exchanged. They have value not only for improving the reliability and accuracy of algorithms of uterine cervix image segmentation, but also promoting collaboration between biomedical experts and engineers which are crucial to medical image-processing applications. Although the CST is designed for the unique characteristics of cervigrams, the BMT and MOSES are very general and extensible, and can be easily adapted to other biomedical image collections. [ABSTRACT FROM AUTHOR]