Effect of grayscale threshold on X-ray computed tomography reconstruction of gas diffusion layers in polymer electrolyte membrane fuel cells.

In X-ray computed tomography (CT) reconstructions of gas diffusion layers (GDLs), grayscale threshold selection is a critical issue. Although various selection methods exist, they all have their own drawbacks. This study investigates the influence of grayscale threshold on GDL properties and compares Otsu and porosity-adaptive thresholds. We utilized X-ray CT to reconstruct a Toray carbon paper sample (TGP-H-060) at a resolution of 2 µm. Using reconstructed 3D models generated under different grayscale thresholds, we performed structural analysis, computational fluid dynamics simulation, and compression simulation. We subsequently calculated porosity, tortuosity, permeability, and macroscopic stress-strain relationships, quantitatively analyzing the sensitivity of these parameters to the change of grayscale threshold. The results indicated that small change in the grayscale threshold can significantly impact the transport and mechanical properties of reconstructed GDLs. The difference between Otsu and porosity-adaptive thresholds is notable, and the porosity-adaptive threshold appears to be less accurate than the Otsu threshold.

Comparison of the photocatalytic degradability of PFOA, PFOS and GenX using Fe-zeolite in water.

Knowledge on the photocatalytic degradability of the emerging poly- and perfluorinated alkyl substances (PFAS) in water, specifically GenX, is limited. GenX has been detected globally in river water and is considered potentially more toxic than legacy PFAS. In this study, we compared the photocatalytic degradability of GenX with the legacy compounds perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) using Fe-zeolite photocatalysts. After 7 h of irradiation, GenX showed lower removal (79%) and defluorination (33%) as compared to PFOA (100% removal and 69% defluorination) and PFOS (100% removal and 51% defluorination). The quasi-first-order degradation rate of GenX (1.5 h1) was 12 and 1.2 times lower than PFOA (18.4 h-1) and PFOS (1.8 h-1), respectively. Additionally, PFOA's defluorination rate (0.9 h-1) was approximately 2.6 and 9 times higher than GenX (0.35 h-1) and PFOS (0.1 h-1), respectively. These outcomes correlate with GenX's lower hydrophobicity, leading to reduced adsorption (40%) compared to PFOA (99%) and PFOS (87%). Based on identified transformation products, we proposed a GenX degradation pathway, resulting in ultra-short-chain PFASs with a chain length of 2 and 3 carbon atoms, while PFOA and PFOS degraded stepwise, losing 1 carbon-fluorine bond at a time, leading to gradually shorter chain lengths (from 7 to 2 carbon atoms). In conclusion, GenX is more challenging to remove and degrade due to its lower adsorption on the photocatalyst, potential steric hindrance, and higher production of persistent ultra-short-chain transformation products through photocatalysis.

Sulfur vacancy rich MoS2/FeMoO4 composites derived from MIL-53(Fe) as PMS activator for efficient elimination of dye: Nonradical 1O2 dominated mechanism.

A novel MoS2/FeMoO4 composite was synthesized for the first time by introducing an inorganic promoter MoS2 into the MIL-53(Fe)-derived PMS-activator. The prepared MoS2/FeMoO4 could effectively activate peroxymonosulfate (PMS) toward 99.7% of rhodamine B (RhB) degradation in 20 min, and achieve a kinetic constant of 0.172 min-1, which is 10.8, 43.0 and 3.9 folds higher than MIL-53, MoS2 and FeMoO4 components, respectively. Both Fe(II) and sulfur vacancies are identified as the main active sites on catalyst surface, where sulfur vacancies can promote adsorption and electron migration between peroxymonosulfate and MoS2/FeMoO4 to accelerate peroxide bond activation. Besides, the Fe(III)/Fe(II) redox cycle was improved by reductive Fe0, S2- and Mo(IV) species to further boost PMS activation and RhB degradation. Comparative quenching experiment and in-situ electron paramagnetic resonance (EPR) spectra verified that SO4•-, •OH, 1O2 and O2•- were produced in the MoS2/FeMoO4/PMS system, while 1O2 dominates RhB elimination. In addition, the influences of various reaction parameters on RhB removal were examined and the MoS2/FeMoO4/PMS system exhibits good performance over a wide pH and temperature range, as well as coexistence with common inorganic ions and humic acid (HA). This study provides a new strategy for preparing MOF-derived composite with simultaneous introduction of MoS2 promotor and rich sulfur vacancies, and enables new insight into radical/nonradical pathway in PMS activation process.

Comparative study on bisphenols oxidation via TiO2 photocatalytic activation of peroxymonosulfate: Effectiveness, mechanism and pathways.

In this work, degradation of bisphenol F (BPF), bisphenol AF (BPAF) and bisphenol S (BPS) by peroxymonosulfate (PMS) with TiO2 nano-tubes arrays (TiO2NTAs) under simulated sunlight irradiation was investigated and compared for the first time. All three bisphenols exhibited appreciable degradation following the order of BPS < BPAF < BPF, and acidic conditions were more conducive to their degradation. The SO4•-, ·OH, h+ and •O2- were all identified in three bisphenols degradation processes. Among these, SO4•- and •O2- were proven to play a dominant role in BPF oxidation process, but SO4•- and h+ were confirmed as the main reactive species for BPAF and BPS removal. Owing to the different reactive species worked in different bisphenols degradation processes, the influences of inorganic anions on three bisphenols degradation were also different. By analyzing the oxidation intermediates of the three bisphenols, it was found that there were some common degradation pathways including bond-cleavage and hydroxylation of the benzene ring shared by three bisphenols. Besides, some specific degradation pathways were also identified, for example, the self-coupling was found in BPF and BPS degradation process, while the benzene ring splitting was occurred only in BPAF transformation process.

Efficacy and safety of apatinib alone or apatinib plus paclitaxel/docetaxel versus paclitaxel/docetaxel in the treatment of advanced non-small cell lung cancer: A meta-analysis.

BACKGROUND: To investigate the efficacy and safety of apatinib alone or apatinib plus paclitaxel/docetaxel versus paclitaxel/docetaxel in the treatment of advanced non-small cell lung cancer (NSCLC) through pooling of open published data. METHODS: The electronic databases of Medline (1960-2021.5), Cochrane central register of controlled trials (CENTRAL), EMBASE(1980-2021.5) and Wan fang (1986-2021.5) were systematically searched by two reviewers to identify the relevant clinical trials related to the above subject. The objective response rate (ORR), disease control rate (DCR) and drug relevant adverse reactions were pooled and demonstrated by risk ratio (RR) and 95% confidence interval (95% CI). The statistical heterogeneity across studies was assessed by I-square test. The publication bias was evaluated by Egger's line regression test and demonstrated by Begg's funnel plot. RESULTS: Eleven prospective studies were included in the meta-analysis. The pooled results indicated that the ORR (RR = 1.62, 95% CI: 1.32-2.00, p < 0.05) and DCR (RR = 1.29, 95% CI: 1.18-1.41, p < 0.05) of apatinib alone or apatinib plus paclitaxel/docetaxel was significantly higher than that of the paclitaxel/docetaxel group for advanced NSCLC, respectively. The drug-related adverse reaction was not statistically different between apatinib alone or apatinib plus paclitaxel/docetaxel with regard to the hand-foot syndrome, gastrointestinal reaction, thrombocytopenia, anemia and leukocytopenia (pall > 0.05) except for hypertension (RR = 3.60, 95% CI: 1.26-10.31, p < 0.05). Subgroup analysis also indicated that the hypertension and hand-foot syndrome in apatinib + paclitaxel/docetaxel were higher than that of the paclitaxel/docetaxel group with a statistical difference (p < 0.05). CONCLUSIONS: Apatinib alone or apatinib plus paclitaxel/docetaxel was superior to paclitaxel/docetaxel for ORR and DCR. However, combined treatment with apatinib appears to increase the risk of a patient developing an adverse reaction, especially hypertension and hand-foot syndrome.

Testing Physical Activity Level as Determinant of Procrastination in Exercise: Will This Direction Work? / Prueba del nivel de actividad física como determinante de la procrastinación en el ejercicio: ¿funcionará esta dirección?

China has witnessed massive economic development in the past few decades and one of the consequences of increased urbanization has been the reduction of physical activity in the adult population. In light of this trend, the researcher has conducted this study with the aim of examining how the low physical activity levels lead to exercise procrastination in the longer run by looking at data collected from Chinese adults that have at least a year or so experience of athletics of any type. The variables that were studied for this purpose in this research include the low level of physical activity as the independent variable, exercise procrastination as dependent and three mediating variable i.e. Low level of perceived self-efficacy in the athletes, perceived task difficulty in the athletes and negative affectivity in the athletes. The researcher conducted an in-depth literature review that led to the formation of 4 hypotheses for direct and indirect relationships. The researcher used positivism to conduct this quantitative research. The nature of research is exploratory with the random sampling technique used to conduct the survey. . Moreover, data is collected through an online questionnaire. The collected data was used to test the hypotheses through statistical and analytical procedures using SPSS. Various tests were applied including descriptive tests, KMO tests, CFA and SEM. The results of SEM showed that the direct impact of low physical activity was insignificant on exercise procrastination. As for the indirect effects, the mediation of negative affect and low self-efficacy were significant while that of perceived task difficulty was insignificant. In addition, the researcher has presented the limitations as well as the future directions that can be adopted in future researches.(AU)

Structure-dependent catalysis of cuprous oxides in peroxymonosulfate activation via nonradical pathway with a high oxidation capacity.

Research interests have been recently thrust into the nonradical reactions in persulfate-based advanced oxidation processes (AOPs), whilst the underlying mechanism of the nonradical pathway remains ambiguous especially in metal-based AOPs systems. In this study, we investigated the reactivity of cuprous oxide (Cu2O) for activating peroxymonosulfate (PMS) to decompose diverse organic contaminants. Cu2O exhibited a strong catalytic dependence on the crystal morphology, and cubic Cu2O was more reactive than the octahedral and rhombic dodecahedral structures for catalytic degradation of bisphenol A with PMS. Chemical quenching tests, electron paramagnetic resonance (EPR), solvent exchange and selective oxidation experiment were corporately conducted to illustrate that Cu2O-catalyzed PMS did not produce free radicals or singlet oxygen. In contrast, a surface-confined metastable intermediate would be formed via outer-sphere interactions between PMS and Cu2O, which directly attacked the organic substrate. Such a reaction pathway is intrinsically distinct from the electron-shuttling regime in carbon (or noble metal)/persulfate systems via the conductive surface of the catalyst, and the outer-sphere interactions let the activated PMS demonstrate a higher oxidizing capacity toward organic contaminants. Therefore, this study dedicates to providing new insights into the copper-catalyzed AOPs and vital supplementary to the ongoing dialogue of the nonradical catalysis in persulfate-based oxidation.

Synthesis of Magnetic CoFe2O4 Nanoparticles and Their Efficient Degradation of Diclofenac by Activating Persulfate via Formation of Sulfate Radicals.

In this study, magnetic CoFe2O4 nanoparticles were synthesized by hydrothermal method by using ferric nitrate and cobalt nitrate as raw materials. Subsequently, physicochemical properties of the resulting CoFe2O4 nanoparticles were systematically studied by scanning electron microscope, X-ray diffraction, N2 adsorption/desorption, Fourier transformation infrared spectroscopy and Vibration sample magnetometer measurement. Results indicated that CoFe2O4 nanoparticles with cubic spinel structure possessed an average diameter of 6.9 nm, specific surface area of 103.48 m2 · g-1, saturation magnetization of 54.65 A · m2(emu · g-1) and coercivity of 1.76×104 A · m-1. Furthermore, scavenging experiments revealed that sulfate radicals (.SO-4) was the main active species derived from persulfates, in which 72.3% of diclofenac could be degraded within 30 min treatment. This study provides a promising strategy to synthesize versatile catalyst which would be potentially applied in pharmaceutical wastewater purification.