Longitudinal In Vivo Imaging of Retinal Ganglion Cells and Retinal Thickness Changes Following Optic Nerve Injury in Mice

Retinal ganglion cells (RGCs) die in sight-threatening eye diseases. Imaging RGCs in humans is not currently possible and proof of principle in experimental models is fundamental for future development. Our objective was to quantify RGC density and retinal thickness following optic nerve transection in transgenic mice expressing cyan fluorescent protein (CFP) under control of the Thy1 promoter, expressed by RGCs and other neurons.A modified confocal scanning laser ophthalmoscopy (CSLO)/spectral-domain optical coherence tomography (SD-OCT) camera was used to image and quantify CFP+ cells in mice from the B6.Cg-Tg(Thy1-CFP)23Jrs/J line. SD-OCT circle (1 B-scan), raster (37 B-scans) and radial (24 B-scans) scans of the retina were also obtained. CSLO was performed at baseline (n = 11) and 3 (n = 11), 5 (n = 4), 7 (n = 10), 10 (n = 6), 14 (n = 7) and 21 (n = 5) days post-transection, while SD-OCT was performed at baseline and 7, 14 and 35 days (n = 9) post-transection. Longitudinal change in CFP+ cell density and retinal thickness were computed. Compared to baseline, the mean (SD) percentage CFP+ cells remaining at 3, 5, 7, 10, 14 and 21 days post-transection was 86 (9)%, 63 (11)%, 45 (11)%, 31 (9)%, 20 (9)% and 8 (4)%, respectively. Compared to baseline, the mean (SD) retinal thickness at 7 days post-transection was 97 (3)%, 98 (2)% and 97 (4)% for the circle, raster and radial scans, respectively. The corresponding figures at 14 and 35 days post-transection were 96 (3)%, 97 (2)% and 95 (3)%; and 93 (3)%, 94 (3)% and 92 (3)%.Longitudinal imaging showed an exponential decline in CFP+ cell density and a small (≤8%) reduction in SD-OCT measured retinal thickness post-transection. SD-OCT is a promising tool for detecting structural changes in experimental optic neuropathy. These results represent an important step towards translation for clinical use

Investigations on the pyrolysis of microalgal-bacterial granular sludge: products, kinetics, and potential mechanisms

This study investigated the pyrolysis of microalgal-bacterial granular sludge for producing bio-oil and biochar. Results showed that the bio-oil productivity of pyrolyzed MBGS reached 39.5-45.4 wt%, while 23.8-41.2% for the nitrogen-containing bio-oil at the temperature of 673-1073 K. Meanwhile the biochar with a nitrogen content of 3.7-7.0 wt% could also be produced. Moreover, the Van-Krevelen diagram revealed that produced bio-oil had a H/C ratio higher than that from agroforestry biomass, but its O/C ratio was found to be similar to those of coal and biochar. It further appeared from a mass conservation analysis that the highest bio-oil production yield was achieved at a pyrolysis temperature of 773 K, while the pyrolytic kinetics of MBGS in the temperature range studied was governed by the 3-D diffusion mechanism with the activation energy of 224.96 kJ·mol-1

Cadmium-effect on performance and symbiotic relationship of microalgal-bacterial granules

So far, the microalgal-bacterial granular sludge process has attracted growing interest as an emerging wastewater treatment technology. Cadmium ion (Cd2+) commonly found in wastewater is toxic to microorganisms, thus its effect on microalgal-bacterial granules was investigated in this study. Results showed that Cd2+ at the concentration above 1 mg/L could compromise the performances of microalgal-bacterial granules. The removal efficiency of chemical oxygen demand decreased from about 70% in the control to 42.2% and 25.0% after 30-day operation at the respective Cd2+ concentrations of 5 and 10 mg/L, while the ammonia-nitrogen removal also declined from 70.4% to 30.5% with the increase of the Cd2+ concentration from 1 to 10 mg/L, indicating that nitrifying bacteria were susceptive to the presence of Cd2+. It was further revealed that Cd2+ could stimulate the production of extracellular polymeric substances, e.g. 190.19 ± 7.04 mg/g VSS in the presence of 10 mg/L of Cd2+ versus 100.26 ± 3.82 mg/g VSS in the control after 10-day operation. More importantly, about 84.1%–94.8% of Cd2+ was found to bind to the extracellular proteins in microalgal-bacterial granules at the Cd2+ concentrations studied. In addition, Chlorococcum and Cyanobacteria in microalgal-bacteria granules were withered in the presence of 10 mg/L of Cd2+, suggesting uncoupled symbiosis between microalgae and bacteria induced by Cd2+. Consequently, this study showed that Cd2+ could negatively impact on the microbial structures and metabolisms of microalgal-bacterial granular sludge, leading to a compromised process performance in terms of organic and nitrogen removal.Shulian Wang is grateful to the financial support from National Natural Science Foundation of China (51909082)

Towards removal of PPCPs by advanced oxidation processes: A review

The continuous influx of emerging contaminants (ECs) into water bodies poses a significant threat to human health. Among these contaminants, pharmaceuticals and personal care products (PPCPs) are of particular concern due to their potential to exert adverse effects even at low concentrations. Therefore, it is imperative to explore methods for their effective removal or reduction to safeguard both human health and the ecological environment. Advanced oxidation processes (AOPs) have received substantial attention as promising treatment methods. AOPs are capable of efficiently treating water by generating reactive oxygen species (ROS) with potent oxidation properties, which can effectively eliminate various contaminants. This review delves into the diverse range of AOPs available, including ozonation, photocatalytic oxidation, the Fenton process, electrochemical oxidation, sulfate radicals-based advanced oxidation processes (SR-AOPs), and more. It also discusses the respective limitations and future prospects of these processes, aiming to provide insights into their potential for addressing the pressing issue of PPCP contamination in water bodies

Almond Shell-Derived, Biochar-Supported, Nano-Zero-Valent Iron Composite for Aqueous Hexavalent Chromium Removal: Performance and Mechanisms

Nano-zero-valent iron biochar derived from almond shell (nZVI-ASBC) was used for hexavalent chromium (CR) removal. Experiments showed that pH was the main factor (p < 0.01) that affected the experimental results. At a dosage of 10 mg.L-1 and pH of 2-6, in the first 60 min, nZVI-ASBC exhibited a removal efficiency of 99.8%, which was approximately 20% higher than the removal yield at pH 7-11. Fourier transform infrared spectroscopy results indicated N-H was the main functional group that influenced the chemisorption process. The pseudo second-order dynamics and Langmuir isotherm models proved to be the most suitable. Thermodynamic studies showed that the reaction was exothermic and spontaneous at low temperatures (T < 317 K). Various interaction mechanisms, including adsorption and reduction, were adopted for the removal of Cr(VI) using the nZVI-ASBC composite. The findings showed that the BC-modified nZVI prepared with almond shell exerts a good effect and could be used for the removal of Cr(VI)

Characteristics and kinetic studies of Hydrilla verticillata pyrolysis via thermogravimetric analysis

The pyrolysis characteristics and kinetic of Hydrilla verticillata (HV) have been investigated using non-isothermal thermogravimetric analysis. The results showed that the pyrolysis behavior of HV can be divided into two independent stages. The kinetics of Stage I was investigated using a distributed activation energy model (DAEM) with discrete 99 first-order reactions. Stage II was an independent stage which corresponds to the decomposition of calcium oxalate, whose kinetics was studied using iso-conversional method together with compensation effect and master-plots method. The activation energies ranged from 92.39 to 506.17 and 190.42 to 222.48 kJ/mol for the first and second stages respectively. Calculated data gave very good fit to the experimental data. (C) 2015 Elsevier Ltd. All rights reserved

Facile Synthesis of Magnetic Biochar Derived from Burley Tobacco Stems towards Enhanced Cr(VI) Removal: Performance and Mechanism

In this study, ferric-loaded magnetic burley tobacco stem biochar (MBTS) was synthesized via pyrolysis to improve the removal of Cr(VI). The results showed that MBTS had an adsorption capacity of 54.92 mg Cr(VI)/g, which was about 14 times higher than raw burley tobacco stem biochar (i.e., 3.84 mg/g). According to the findings obtained, a three-step mechanism of Cr(VI) removal by MBTS was further put forward, i.e., (1) Cr(VI) exchanged with hydroxyl groups on MBTS, (2) the reduction in Cr(VI) to Cr(III) mediated by oxygen-containing groups, and (3) the chelation of produced Cr(III) with the amino groups on MBTS. FTIR spectra further revealed that C-N, C-H, and C=C groups played an important role in Cr(VI) removal. Furthermore, the adsorption equilibrium and kinetics of Cr(VI) on MBTS could better be described by the Langmuir equation and pseudo-second-order rate equation. This study clearly demonstrated that ferric-loaded biochar derived from burley tobacco stems could serve as a cost-effective magnetic adsorbent for the high-efficiency removal of soluble Cr(VI) from wastewater. Tobacco stem-adsorbed Cr(VI) realized a green path for treating waste by waste