A novel algicidal properties of fermentation products from Pseudomonas sp. Ps3 strain on the toxic red tide dinoflagellate species

The viability of both China’s offshore fishing operations and the global marine fishing industry is threatened by the occurrence of red tides caused by Gymnodinium catenatum and Karenia mikimotoi. Effective control of these dinoflagellate-mediated red tides has become a pressing issue that requires immediate attention. In this study, High-efficiency marine alginolytic bacteria were isolated and underwent molecular biological identification to confirm their algicidal properties. Based on a combination of morphological, physiological, biochemical, and sequencing results, Strain Ps3 was identified as belonging to the species Pseudomonas sp. We examine the effects of algicidal bacteria on the red tide species G. catenatum and K. mikimotoi within an indoor experimental setting. Then gas chromatography– mass spectrometry (GC–MS) was used to analyze the structure of the algolytic active substances. This investigation demonstrated that with exposure to the algae-lysis experiment, the Ps3 strain has the best algae-lysis effect, with G. catenatum and K. mikimotoi reaching 83.0 and 78.3%. Our results from the sterile fermentation broth experiment showed that the inhibitory effect on the two red tide algae was positively correlated with the concentration of the treatment. At a treatment concentration of 2.0% (v/v), the 48 h lysis rates of G. catenatum and K. mikimotoi due to exposure to the Ps3 bacterial fermentation broth were 95.2 and 86.7%, respectively. The results of this study suggest that the algaecide may be a rapid and effective method to control dinoflagellate blooms, as evidenced by the observed changes in cellular morphology in all cases. In the ethyl acetate phase of Ps3 fermentation broth, the cyclic (leucine-leucine) dipeptide was the most abundant. The findings of this study contribute to our understanding of red tide prevention and control and provide a theoretical foundation for further research in this field

Surface deformation and damage of 2022 (M 6.8) Luding earthquake in China and its tectonic implications

The 2022 (M 6.8) Luding earthquake on the Xianshuihe Fault Zone (XFZ) caused severe casualties and property losses, and surface deformation and damage of which is crucial for studying the earthquake hazard assessment. However, few intensive scientific understanding has obtained to date because of widespread coronavirus transmission, strong vegetation coverage, and post-earthquake paralyzed traffic. By integrating high-resolution satellite images, large-scale geomorphic mapping, and UAV surveys, we constrain coseismic fractures and ruptures along an NW-SE-trending surface deformation zone, with discontinuous geomorphic scarps, en echelon cracks, and bulges concentrated in the areas of Yanzigou, Moxi, Menghugang, and Xingfu villages near the epicenter. Field observation also shows that the zone extends nearly parallel to the pre-existing XFZ with a length of ∼35 km with variable widths and a maximum vertical displacement of ∼100 ± 10 cm. The earthquake-induced surface coseismic effects, such as landslides, rock falls, and collapses, caused damage to the area. The amplification effect of the topography and the improper aseismic design and poor constructions may be responsible for the spatial distribution of MM Intensity IX, which is larger than other previous earthquakes that occurred in the surrounding area with a similar tectonic setting

Effect of Torrefaction Pretreatment on Chemical Structure and Pyrolysis Behaviors of Cellulose

Abstract In order to obtain the effect of torrefaction pretreatment on chemical structure and pyrolysis reactivity of cellulose, torrefaction of cellulose was conducted in a fixed bed reactor at varying torrefaction temperature and residence time. The chemical composition and structural alterations of torrefied cellulose were characterized by elemental analyzer and Fourier-transform infrared spectroscopy (FTIR). The investigation on the pyrolysis behaviors of raw and torrefied cellulose were carried out by using a thermogravimetric analyzer (TGA). The results showed that torrefaction of cellulose mainly proceeded a series of deoxygenation, polycondensation and carbonization reactions. The severe carbonization of cellulose occurred when the torrefaction temperature and residence time were larger than 300°C and 40 min, resulting in the drastic decrease in the pyrolysis reactivity of cellulose. Hence, the optimal torrefaction temperature should not exceed 280°C

Laboratory experiment on the nano-TiO2 photocatalytic degradation effect of road surface oil pollution

Oil leak from vehicles is one of the most common pollution types of the road. The spilled oil could be retained on the surface and spread in the air voids of the road, which results in a decrease in the friction coefficient of the road, affects driving safety, and causes damage to pavement materials over time. Photocatalytic degradation through nano-TiO2 is a safe, long-lasting, and sustainable technology among the many methods for treating oil contamination on road surfaces. In this study, the nano-TiO2 photocatalytic degradation effect of road surface oil pollution was evaluated through the lab experiment. First, a glass dish was used as a substrate to determine the basic working condition of the test; then, a test method considering the impact of different oil erosion degrees was proposed to eliminate the effect of oil erosion on asphalt pavement and leakage on cement pavement, which led to the development of a lab test method for the nano-TiO2 photocatalytic degradation effect of oil pollution on different road surfaces

The Damage Threshold of Multilayer Film Induced by Femtosecond and Picosecond Laser Pulses

Laser-induced damage threshold (LIDT) is an essential factor in measuring the anti-laser damage of optical films. The damage threshold and morphology of the Ta2O5/SiO2 multilayer film prepared by electron beam evaporation were studied by femtosecond (50 fs) and picosecond (30 ps) laser irradiations. The results showed that the LIDT of the film was 1.7 J·cm−2 under the femtosecond laser. The damage morphology developed from surface damage to a clear layered structure, and the outline has become more transparent and regular with an increase in the laser fluence. Under the picosecond laser irradiation, the LIDT of the film was 2.0 J·cm−2. The damage morphology developed from small range to thin film layer separation, and the outline changed from blurry to clear with an increase in laser fluence. Therefore, the LIDT of the film decreased with a decrease in the laser pulse width

Uncovering Structure-Reactivity Relationships in Pyrolysis and Gasification of Biomass with Varying Severity of Torrefaction

The objective of this study is to establish the structure reactivity relationships in pyrolysis and gasification of biomass with varying severity of torrefaction. Pine was torrefied in a bench scale tubular reactor with varying torrefaction temperature (220-300 degrees C). The structural alterations in torrefied pine and its derived biochar were characterized by solid-state nuclear magnetic resonance spectroscopy (NMR) and Raman spectroscopy, respectively. The effect of torrefaction severity, as well as the resulting structural changes in pine, upon subsequent pyrolysis and gasification reactivity were systematically studied. The experimental results showed that the pyrolysis reactivity of pine was promoted by torrefaction, whereas the gasification reactivity of biochar derived from pine was reduced by torrefaction. The results were mainly attributed to the severe degradation, polycondensation, and carbonization of hemicellulose and lignin fractions during torrefaction of pine. The pyrolysis and gasification reactivity of torrefied pine was a strong linear function of its aromaticity or H/C molar ratio. Therefore, H/C molar ratio and aromaticity of pine were good indicators to quantitatively assess the structural alterations of pine during torrefaction and their impacts on the reactivity of subsequent pyrolysis and gasification. These findings provide a simple and efficient method to predict the pyrolysis and gasification reactivity of biomass with varying severity of torrefaction

Ceftriaxone Calcium Crystals Induce Acute Kidney Injury by NLRP3-Mediated Inflammation and Oxidative Stress Injury

Objective. To investigate the role of inflammatory reactions and oxidative stress injury in the mechanisms of ceftriaxone calcium crystal-induced acute kidney injury (AKI) both in vivo and in vitro. Methods. Male Sprague Dawley rats were randomly divided into five groups of ten each according to different concentrations of ceftriaxone and calcium. Based on the levels of serum creatinine (Scr) and blood urea nitrogen (BUN), the AKI group was chosen for the subsequent experiments. Kidney histological examination and immunohistochemistry were performed. The expression of NLRP3 and IL-1β protein and the concentrations of oxidative stress markers such as ROS, MDA, and H2O2 in kidney tissues were estimated. In parallel, HK-2 human renal proximal tubule cells were exposed to ceftriaxone calcium crystals. The mRNA expression levels of NLRP3 and IL-1β and the concentrations of oxidative stress markers were evaluated. Finally, cell viability and rat survival were also assessed. Results. The results showed that significantly increased Scr and BUN levels, consistent with morphological changes and kidney stones, were found in the rats that received the highest concentration of ceftriaxone (1000 mg/kg) combined with calcium (800 mg/kg). The activation of the NLRP3 inflammasome axis and the marked elevation of MDA, H2O2, and ROS levels were observed both in vivo and in vitro. High expression of Nrf2, HO-1, and NQO1 was also documented. In addition, cell apoptosis and rat mortality were promoted by ceftriaxone calcium crystals. Conclusions. Notably, we found that ceftriaxone-induced urolithiasis was associated with a high risk of AKI and NLRP3-mediated inflammasome and oxidative stress injury were of major importance in the pathogenesis

Effect of Femtosecond Laser Polarization on the Damage Threshold of Ta₂O₅/SiO₂ Film

The study used linearly and circularly polarized femtosecond pulsed lasers to irradiate a Ta2O5/SiO2 film. Firstly, the damage thresholds of the film for linearly and circularly polarized femtosecond pulsed lasers were measured in 1-on-1 mode. The results showed that the damage threshold (1.70 J/cm2) under a circularly polarized laser was higher than that (1.68 J/cm2) under a linearly polarized laser. For femtosecond lasers, the multi-photon ionization cross-section under circular polarization was lower than that under linear polarization. The lower ionization rate under circular polarization led to a higher damage threshold compared to the case under linear polarization. Secondly, the damage morphology of the film irradiated by linearly and circularly polarized femtosecond lasers was observed by microscope. The damage caused by linearly polarized laser was more evident than that caused by the circularly polarized laser. Finally, the damage thresholds induced by linearly and circularly polarized femtosecond pulsed lasers were measured in S-on-1 (S = 2, 5, and 10) mode. For the same S value (2, 5, or 10), the damage threshold under the circularly polarized laser was higher than that under the linearly polarized laser. The damage thresholds under two polarized laser pulses decreased with an increase in the number of laser shots, indicating that repeated laser pulses had a cumulative effect on the damage of the film

Reducing emission of NOx and SOx precursors while enhancing char production from pyrolysis of sewage sludge by torrefaction pretreatment

This study aims to explore the possibility of reducing emission of NOx and SOx precursors while enhancing char production from pyrolysis of sewage sludge by torrefaction pretreatment. The influence of torrefaction severity on structural alterations of sewage sludge and resulting pyrolysis behaviors was systematically studied. The experimental results show that 33.3% of N and 52.8% of S in sewage sludge can be removed by torrefaction pretreatment, leading to the evident reduction in the emission of NOx and SOx precursors (e.g. NH3, HCNO, H2S, COS and CS2) during subsequent pyrolysis of torrefied sewage sludge. Moreover, the yield and specific surface area of char from pyrolysis of sewage sludge can be improved by torrefaction. The char obtained from pyrolysis of sewage sludge torrefied at 300 degrees C exhibited the highest yield of 61.0 wt% and the maximum BET surface areas of 26.5 m(2)/g. These results could be ascribed to the devolatilization, polycondensation and charring of sewage sludge during torrefaction to form torrefied sewage sludge with stable aromatic and heterocyclic structure. These findings suggest that torrefaction is an effective pretreatment method prior to pyrolysis of sewage sludge for reducing emission of NOx and SOx precursors while enhancing yield and specific surface area of char. (C) 2019 Elsevier Ltd. All rights reserved

Data_Sheet_1_A novel algicidal properties of fermentation products from Pseudomonas sp. Ps3 strain on the toxic red tide dinoflagellate species.docx

The viability of both China’s offshore fishing operations and the global marine fishing industry is threatened by the occurrence of red tides caused by Gymnodinium catenatum and Karenia mikimotoi. Effective control of these dinoflagellate-mediated red tides has become a pressing issue that requires immediate attention. In this study, High-efficiency marine alginolytic bacteria were isolated and underwent molecular biological identification to confirm their algicidal properties. Based on a combination of morphological, physiological, biochemical, and sequencing results, Strain Ps3 was identified as belonging to the species Pseudomonas sp. We examine the effects of algicidal bacteria on the red tide species G. catenatum and K. mikimotoi within an indoor experimental setting. Then gas chromatography– mass spectrometry (GC–MS) was used to analyze the structure of the algolytic active substances. This investigation demonstrated that with exposure to the algae-lysis experiment, the Ps3 strain has the best algae-lysis effect, with G. catenatum and K. mikimotoi reaching 83.0 and 78.3%. Our results from the sterile fermentation broth experiment showed that the inhibitory effect on the two red tide algae was positively correlated with the concentration of the treatment. At a treatment concentration of 2.0% (v/v), the 48 h lysis rates of G. catenatum and K. mikimotoi due to exposure to the Ps3 bacterial fermentation broth were 95.2 and 86.7%, respectively. The results of this study suggest that the algaecide may be a rapid and effective method to control dinoflagellate blooms, as evidenced by the observed changes in cellular morphology in all cases. In the ethyl acetate phase of Ps3 fermentation broth, the cyclic (leucine-leucine) dipeptide was the most abundant. The findings of this study contribute to our understanding of red tide prevention and control and provide a theoretical foundation for further research in this field.</p