Unveiling the mechanisms of peracetic acid activation by iron-rich sludge biochar for sulfamethoxazole degradation with wide adaptability.

Advanced oxidation processes (AOPs) based on peracetic acid (PAA) has been extensively concerned for the degradation of organic pollutants. In this study, metallic iron-modified sludge biochar (Fe-SBC) was employed to activate PAA for the removal of sulfamethoxazole (SMX). The characterization results indicated that FeO and Fe2O3 were successfully loaded on the surface of the sludge biochar (SBC). Fe-SBC/PAA system achieved 92% SMX removal after 30 min. The pseudo-first-order kinetic reaction constant of the Fe-SBC/PAA system was 7.34 × 10-2 min-1, which was 2.4 times higher than the SBC/PAA system. The degradation of SMX was enhanced with increasing the Fe-SBC dosage and PAA concentration. Apart from Cl-, NO3- and SO42- had a negligible influence on the degradation of SMX. Quenching experiments and electron paramagnetic resonance (EPR) techniques identified the existence of reactive species, of which CH3C(O)OO•, 1O2, and O2•- were dominant reactive species in Fe-SBC/PAA system. The effect of different water matrices on the removal of SMX was investigated. The removal of SMX in tap water and lake water were 79% and 69%, respectively. Four possible pathways for the decay of SMX were presented according to the identification of oxidation products. In addition, following the ecological structure-activity relationship model (ECOSAR) procedure and the germination experiments with lettuce seeds to predict the toxicity of the intermediates. The acute and chronic ecotoxicity of SMX solution was dramatically diminished by processing with Fe-SBC/PAA system. In general, this study offered a prospective strategy for the degradation of organic pollutants.

Performance Analysis of UAV-Assisted Hybrid FSO/RF Communication Systems under Various Weather Conditions.

Nowadays, unmanned aerial vehicle (UAV) communication systems are commonly considered as one of the key enabling technologies for 6G. The hybrid free space optical (FSO)/radio frequency (RF) system has the advantages of both FSO and RF links to improve communication system performance, and the relay-assisted system adopts multi-hop transmission and cooperative diversity methods to extend communication coverage. Thus, a joint consideration of UAV-assistedUAV assisted relay in hybrid FSO/RF transmission is meaningful. In this paper, we aim to analyze the performance of UAV-assisted multi-hop parallel hybrid FSO/RF communication systems with and without pointing errors (PE) in terms of Bit Error Rate (BER) and outage probability. In our considered system, the FSO sub-link adopts the Exponential Weibull turbulence model and the RF sub-link suffers the Nakagami fading model. With these, new mathematical formulas of both BER and outage probability are derived under the UAV-assisted hybrid FSO/RF with different modulation methods. Through numerical evaluationnumerical simulations, the performances of UAV-assisted hybrid FSO/RF systems are analyzed under different weather conditions, modulation methods, optical receiver aperture, RF fading parameters, pointing errors, and relay structures. The results demonstrate that (1) compared to hybrid FSO/RF direct links, UAV-assisted hybrid FSO/RF systems can further improve system performance; (2) the performance of UAV-assisted hybrid FSO/RF systems varies with different relay structures; (3) large receiver aperture and RF fading parameters can further improve the communication performance of hybrid FSO/RF direct links and UAV-assisted hybrid FSO/RF systems.

Performance Analysis of Relay-Aided Hybrid FSO/RF Cooperation Communication System over the Generalized Turbulence Channels with Pointing Errors and Nakagami-m Fading Channels.

To improve the performance of fee-space optical communication systems, this paper analyzes the performance of a relay-aided hybrid fee-space optical (FSO)/radio frequency (RF) cooperation system based on a selective combination and decoding forward transmission scheme. In this system, the FSO sub-link experienced Málaga turbulence with pointing errors and the RF sub-link suffered Nakagami-m fading. Firstly, the probability density function (PDF) and cumulative distribution function (CDF) of the end-to-end output signal-to-noise ratio (SNR) of the relay-aided hybrid FSO/RF system are derived. Then, using the extended generalized bivariate Meijer's G-function (EGBMGF) and the approximate analytical formula of the generalized Gauss-Laguerre integral, mathematical expressions of the end-to-end average bit error rate (ABER) and outage probability of the relay-aided hybrid FSO/RF system with different subcarrier intensity modulation and different detection schemes are derived. Through a simulation analysis of the system, the results show that compared with the other three modulation technologies, the hybrid FSO/RF direct link and relay-aided hybrid FSO/RF system with coherent binary phase shift keying (CBPSK) modulation have the best bit error performance. Compared with direct detection, the hybrid direct link and relay-aided hybrid system with coherent detection can significantly improve the communication performance. Increasing the RF fading parameter m can further improve the bit error and outage performance of the hybrid direct link and relay-aided hybrid system; the hybrid direct link can significantly mitigate the degradation of communication performance in the FSO system caused by pointing errors, and the relay-aided hybrid system can further improve the communication performance; under weak turbulence conditions, the impact of pointing errors on the performance of the relay-aided hybrid system can even be ignored. The greater the total number of paths in the relay-aided hybrid system, the better the communication performance of the system; however, the more hops, the worse the performance of the system. The outage probability of the hybrid direct link and relay-aided hybrid system are very sensitive to the decision threshold, and the larger the decision threshold, the worse the outage performance. The transmission distance of different hybrid direct links has little impact on the performance of hybrid direct links and relay-aided hybrid systems. Improving the signal-to-noise ratio of RF sub-links significantly improves the performance of hybrid direct links and relay-aided hybrid systems.

Ball milling-assisted preparation of sludge biochar as a novel periodate activator for nonradical degradation of sulfamethoxazole: Insight into the mechanism of enhanced electron transfer.

The non-radical pathway of periodate (PI) activation for the removal of persistent organic contaminants has received increasing attention due to its higher stability and oxidative advantages. In this study, the degradation of sulfamethoxazole (SMX) by ball mill treated magnetic sludge biochar (BM-MSBC) through activation of PI by electron transfer mechanism was reported. Experimental and characterization results showed that the ball milling treatment resulted in a better pore and defect structure, which also significantly enhanced the electron transfer capacity of the sludge biochar. The BM-MSBC/PI system exhibited notable dependence of activator concentration and initial pH, while the effect of PI concentration was not significant. The coexisting substances (common anions and natural organic matters) hardly affect the degradation of SMX in the BM-MSBC/PI system. The phytotoxicity experiments suggested that the treatment of BM-MSBC/PI system could significantly reduce the biological toxicity of SMX solution. This study provides a novel, economical, and facile modification method for the application of sludge biochar in advanced oxidation processes.

Low CP Overhead Waveform Design for Multi-Path Channels with Timing Synchronization Error.

In classical orthogonal frequency division multiplexing (OFDM) systems, inserting the cyclic prefix (CP) is necessary before each symbol to overcome the multi-path effect, which, however, occupies numerous time-frequency radio resources, resulting in hampered spectrum efficiency. To address this issue, in this paper, symbol repetition aware OFDM (SR-OFDM) is developed to lower the overhead of CP. In the proposed SR-OFDM, multiple symbols share the same CP with which we examine that the multi-path channels can also be overcome by a simple single-tap equalization without causing any interference. Moreover, after the discrete Fourier transform at the receiver, different symbols are proved to be separated in the time domain, which is beneficial for lowering the demodulation complexity. Furthermore, it is revealed that the above conclusions still hold even under timing synchronization errors, which makes the proposed SR-OFDM favorable in real systems. Extensive simulations validate the efficacy of our proposed SR-OFDM system under the multi-path channels with or without timing synchronization errors.

Imaging a defect in layered media with different shaped interfaces using reverse time migration without velocity model known a priori.

In this work, the highly accurate image of a defect in the layered media using a reverse time migration (RTM) is obtained without priori information of the interface geometry and acoustic velocity of the lower medium. The interface of layered media is reconstructed by RTM, and its profile is determined using the reconstructed image within the range of -6 to 0 dB. At the assumed acoustic velocity of the lower medium, the minimum variance of the possible position distribution of a defect is evaluated to be an acoustic velocity of the lower medium by processing the travel times of the defect scattered echoes. The velocity model of the layered media is reconstructed by the mapped interface and the calibrated acoustic velocity of the lower medium, and a defect in the layered media is imaged by RTM. The proposed method is verified by utilizing the silicone rubber-water layered media with horizontal, titled, and circular arc interfaces. The obtained results for the interface geometry, acoustic velocity of the lower medium, and location of defect are consistent with the actual values. Therefore, a defect in the layered media can be accurately located and imaged without the velocity model of layered media known a priori via the RTM method.

Poricoic acid A (PAA) inhibits T-cell acute lymphoblastic leukemia through inducing autophagic cell death and ferroptosis.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive cancer with poor clinical outcome. Poricoic acid A (PAA) is the main chemical constituent on the surface layer of the mushroom Poria cocos, and exerts protective effects against various diseases. In the study, its effects on T-ALL progression were investigated both in vitro and in vivo. Our results showed that PAA strongly reduced the cell viability of T-ALL cell lines, and induced cell G2 cycle arrest and apoptosis in vitro. Mitochondrial dysfunction was also elevated by PAA, along with enhanced cellular reactive oxygen species (ROS) production. Importantly, PAA-suppressed cell viability and -triggered apoptosis were ROS-dependent. Additionally, autophagy was significantly induced by PAA in T-ALL cells through regulating AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) and LC3 signaling pathways. PAA treatments also provoked ferroptosis in T-ALL cells with reduced glutathione (GSH) levels and elevated malonaldehyde (MDA) contents. Suppressing autophagy and ferroptosis almost abrogated the capacity of PAA to restrain T-ALL proliferation and growth. The effects of PAA to suppress T-ALL tumor growth were also confirmed in vivo with undetectable toxicity. Therefore, the present study highlighted the potential of PAA for T-ALL treatment mainly through inducing autophagic cell death and ferroptosis.

Significance changes in the levels of myocardial enzyme in the child patients with Mycoplasma Pneumoniae Pneumonia.

Mycoplasma is a gram-negative with thin wall bacterium that in humans, Mycoplasma pneumoniae causes pneumonia. This experiment was designed to explore the changes of myocardial enzymes in the mycoplasma pneumoniae pneumonia (MPP) child patients, and analyze the clinical value of these changes, in combination with the relevant indicators, symptoms and signs, in the evaluation of the pneumonia mycoplasma infection. For this aim, a total of 120 child patients with MPP in the acute phase,120 child patients with MPP in the recovery phase and 120 healthy children were simultaneously enrolled into this study to detect the levels of aspartate aminotransferase (AST), creatine kinase (CK), Creatine Kinase Isoenzyme (CK-MB) and lactic dehydrogenase (LDH) in blood. Results showed that MPP patients in the acute phase had higher levels of LDH, CK, CK-MB, AST, PCt, CRP, MPV, PDW, PCt, percentage of neutrophils, WBC count in the peripheral blood and ESR than those of the patients in the recovery patients and healthy children, while the level of PLT was lower (all P<0.05). In the acute phase, the level of CK-MB correlated to the fever, fever duration, extrapulmonary organ damage (except for the myocardial damage) and the antibody titer of MP (all P<0.05). It was concluded that in the acute phase of MMP, the level of CK-MB could not only reflect the myocardial damage readily but also the infection of MP as well as the resultant inflammation and disease progression, which could effectively guide the diagnosis and treatment of MPP.

Continuous hydrogenation of ethyl levulinate to γ-valerolactone and 2-methyl tetrahydrofuran over alumina doped Cu/SiO2 catalyst: the potential of commercialization.

Hydrogenation of levulinic acid (LA) and its esters to produce γ-valerolactone (GVL) and 2-methyl tetrahydrofuran (2-MTHF) is a key step for the utilization of cellulose derived LA. Aiming to develop a commercially feasible base metal catalyst for the production of GVL from LA, with satisfactory activity, selectivity, and stability, Al2O3 doped Cu/SiO2 and Cu/SiO2 catalysts were fabricated by co-precipitation routes in parallel. The diverse physio-chemical properties of these two catalysts were characterized by XRD, TEM, dissociative N2O chemisorptions, and Py-IR methods. The catalytic properties of these two catalysts were systematically assessed in the continuous hydrogenation of ethyl levulinate (EL) in a fixed-bed reactor. The effect of acidic property of the SiO2 substrate on the catalytic properties was investigated. To justify the potential of its commercialization, significant attention was paid on the initial activity, proper operation window, by-products control, selectivity, and stability of the catalyst. The effect of reaction conditions, such as temperature and pressure, on the performance of the catalyst was also thoroughly studied. The development of alumina doped Cu/SiO2 catalyst strengthened the value-chain from cellulose to industrially important chemicals via LA and GVL.

A comparative first principles study on trivalent ion incorporated SSZ-13 zeolites.

The dispersion-corrected density functional theory has been used to study the trivalent ions B, Al, Ga, and Fe incorporated SSZ-13-type zeolites. The associated structure and Brønsted/Lewis acidity change caused by the incorporation ions were comparatively studied. It was found that the smaller the radius differences of the incorporation ions are, the smaller the changes in the structure will be and the less acidity will be enhanced for the Brønsted sites. The trivalent Al is found to be the most favorable trivalent incorporation ion and Na is found to be the most favorable charge balanced ion for the synthesis of SSZ-13-type zeolites due to size comparability, which are in line with the experimental observation. The substitution energies which show the relative synthesis difficulty level were also applied for B, Al, Ga, and Fe incorporated zeolites and found that the difficulty decreases with order of Fe > B > Ga ≫ Al, also in good agreement with the experimental observations. Adsorption studies for the NH3 and pyridine molecules indicate that adsorption on the Brønsted acid sites is more stable than on the Lewis acid sites. The Brønsted acidity was found to follow the order of HAl-SSZ-13 > HGa-SSZ-13 ≈ HFe-SSZ-13 > HB-SSZ-13 where the Lewis acidity was found to follow the order of HGa-SSZ-13 ≈ HFe-SSZ-13 > HAl-SSZ-13 > HB-SSZ-13. Our results provide new insights for the synthesis of the SSZ-13-type zeolites and fundamental information for the zeolitic catalyst designation to enhance the catalytic performance.

Synthesis of ZSM-5 with intracrystal or intercrystal mesopores by polyvinyl butyral templating method.

Three facile routes were utilized to synthesize ZSM-5 materials with intracrystal or intercrystal mesopores, where the polyvinyl butyral gel served as mesopore directing template. The three routes were divided into two synthesis strategies: the hydrothermal treatment of silica/PVB composite and re-crystallization of preformed zeolite precursor with the assistance of PVB gel. The fabrication of silica/PVB composite was accomplished by two routes including sol-gel process and impregnation method. The resulting composite was undergone hydrothermal treatment. During the crystallization PVB was occluded in the ZSM-5 crystal, creating intracrystal mesopores in the zeolite. The last route for the synthesis of mesoporous ZSM-5 was realized by re-crystallization of preformed ZSM-5 zeolite in the presence of PVB. This route involved the pre-crystallization of the amorphous aluminosilicate to produce the pre-formed ZSM-5 precursor. Upon further crystallization of the mixture of PVB gel and pre-formed ZSM-5, the ZSM-5 precursor was transformed into ZSM-5 aggregate of nanocrystals, while the PVB gel was occluded in the ZSM-5 particles. Removal of the template generated the typical microporosity associated with ZSM-5 structure along with intercrystal mesoporosity produced from the PVB. The mesoporous ZSM-5 exhibited enhanced catalytic activity in the toluene disproportionation and transalkylation with C(9) and C(10) aromatics.