Search Results (1,421)

In response to the challenges of food spoilage and water pollution caused by pathogenic microorganisms, CeO₂/g-C₃N₄ nanocomposites were synthesized via one-step calcination using thiourea and urea as precursors. Steady-state photoluminescence (PL) spectroscopy analysis demonstrated that 8 wt% CeO₂/g-C₃N₄ exhibited superior electron–hole separation efficiency. Quantitative antimicrobial assays demonstrated that the nanocomposites displayed enhanced bactericidal activity against Escherichia coli, Ralstonia solanacearum, and Staphylococcus aureus. Electron paramagnetic resonance (EPR) spectroscopy analysis verified the generation of hydroxyl radicals (·OH) and superoxide radicals (·O₂⁻) during the photo-Fenton process utilizing CeO₂/g-C₃N₄ nanocomposites. Additionally, 8 wt% CeO₂/g-C₃N₄ nanocomposites demonstrated enhanced photocatalytic degradation of rhodamine B (RhB) and tetracycline hydrochloride (TC) under photo-Fenton conditions. Full article

Background: Glioblastoma multiforme (GBM) is the most common highly aggressive, primary malignant brain tumor in adults. Current experimental strategies include photodynamic therapy (PDT) and new drug delivery technologies such as nanoparticles, which could play a key role in the treatment, diagnosis, and imaging of brain tumors. Objectives: The purpose of this study was to test the efficacy of PDT using AGuIX-TPP, a polysiloxane-based nanoparticle (AGuIX) that contains TPP (5,10,15,20-tetraphenyl-21H,23H-porphine), in biological models of glioblastoma multiforme and to investigate the vascular mechanisms of action at multiple complexity levels. Methods: PDT effects were studied in monolayer and spheroid cell culture, as well as tumors in chicken chorioallantoic membranes (CAMs) and in mice were studied. Results: Treatment was effective in both endothelial ECRF and glioma U87 cells, as well as in the inhibition of growth of the glioma spheroids. PDT using AGuIX-TPP inhibited U87 tumors growing in CAM and destroyed their vascularization. The U87 tumors were also grown in nude mice. Their vascular network, as well as oxygen partial pressure, were assessed using ultrasound and EPR oximetry. The treatment damaged tumor vessels and slightly decreased oxygen levels. Conclusions: PDT with AGuIX-TPP was effective against glioma cells, spheroids, and tumors; however, in mice, its efficacy appeared to be strongly related to the presence of blood vessels in the tumor before the treatment. Full article

The nuclear industry uses 304L stainless steel to construct canisters for storing spent nuclear fuel. The spent nuclear fuel canisters require the lifetime prediction and robustness of their corrosion behavior over periods ranging from thousands to hundreds of thousands of years. Since nuclear power plants are predominantly located in coastal areas, where storage conditions are highly vulnerable to chloride environments, extensive research has been conducted to enhance the canisters’ stress corrosion cracking (SCC) resistance. The welded canisters inherently possess residual tensile stress, prompting the application of plastic deformation-based techniques to boost their SCC resistance, with peening being the most prevalent method. It is reported that UNSM increases the SCC resistance by plastic deformation through surface treatment. In this study, the commercial 304L stainless steel was subjected to UNSM treatment on base metal, heat affected zone (HAZ), and weld metal U-bend test specimens to induce compressive residual stresses up to a depth of 1 mm. The impact of peening treatment on SCC properties was explored through microstructural analysis, corrosion properties analysis, and compressive residual stress assessments. The U-bend specimens underwent SCC testing (in 42% MgCl₂ at 155 °C), microstructure examination using an optical microscope (OM) and a scanning electron microscope (SEM), electron backscatter diffraction (EBSD) analysis, and compressive residual stress measurements via the hole-drilling method. Corrosion behavior on the surface and cross-section was evaluated using anodic polarization tests, electrochemical impedance spectroscopy (EIS) measurements, double loop-electrochemical potentiokinetic reactivation (DL-EPR) tests, and ASTM A262 Pr. C tests. The compressive residual stress imparted by UNSM refined the outermost grains of the cross-section and enhanced the corrosion resistance of 304L stainless steel. Furthermore, it led to a longer crack initiation time, a reduced crack propagation rate, and improved SCC properties. Full article

Antioxidants are the most popular active ingredients in anti-aging cosmetics as they can restore the physiological radical balance and counteract the photoaging process. Instead of adding pure compounds into the formulations, some “precious” vegetable oils could be used due to their content of tocopherols, phenols, vitamins, etc., constituting a powerful antioxidant unsaponifiable fraction. Here, electron paramagnetic resonance (EPR) spectroscopy coupled with spin trapping was proven to provide a valid method for evaluating the antioxidant properties and the oxidative resistance of vegetable oils which, following UV irradiation, produce highly reactive radical species although hardly detectable. Extra virgin olive oil, sweet almond oil, apricot kernel oil, and jojoba oil were then evaluated by using N-t-butyl-α-phenylnitrone as a spin trapper and testing different UV irradiation times followed by incubation for 5 to 180 min at 70 °C. The EPR spectra were manipulated to obtain quantitative information useful for comparing the different tested samples. As a result, the knowledge acquired via the EPR analyses demonstrated jojoba oil as the best of the four considered oils in terms of both starting antioxidant ability and oxidative stability overtime. The obtained results confirmed the usefulness of the EPR spin trapping technique for the main proposed purpose. Full article

This review provides a detailed analysis of zero waste (ZW) initiatives, focusing on national policies, strategies, and case studies aimed at minimising municipal solid waste (MSW). It evaluates the environmental, social, and economic impacts of waste and explores the transition from conventional landfill reliance to sustainable waste management practices. Key ZW approaches, including circular economy frameworks and extended producer responsibility (EPR), are examined through case studies from countries such as China, Germany, and the United States. The review highlights advancements in waste-to-energy (WTE) technologies, the development of zero waste cities, and the critical role of policies in achieving significant MSW reduction. Additionally, it identifies key challenges such as infrastructure gaps and regulatory weaknesses and offers practical solutions to overcome these barriers. This study serves as a valuable resource for policymakers aiming to implement effective waste reduction strategies and enhance sustainable waste management systems globally. Full article

This study analyzed the operational environment of supply chains involved in the production of eco-friendly plastics, with a particular emphasis on small- and medium-sized businesses worldwide. Qualitative research methods were used to highlight the significance of extended producer responsibility (EPR) regulations and strong recycling programs for the sustainability of small- and medium-sized enterprises (SMEs). Also, this study looked at international regulations affecting the implementation of circular economy strategies and the difficulties in creating sustainable supply chains. It concluded that waste reduction, effective supply chain management, and sustainable practices are crucial aspects of a more effective and sustainable global plastic-manufacturing sector. This research highlighted the significance of government policies in SME revival and used Multiple-Criteria Decision Analysis (MCDA) to help SMEs adopt sustainable supply chain practices that act as a catalyst for industry reform. Full article

The disorder and heterogeneity of low-molecular-weight amyloid-beta oligomers (AβOs) underlie their participation in multiple modes of cellular dysfunction associated with the etiology of Alzheimer’s disease (AD). The lack of specified conformational states in these species complicates efforts to select or design small molecules to targeting discrete pathogenic states. Furthermore, targeting AβOs alone may be therapeutically insufficient, as AD progresses as a multifactorial, self-amplifying cascade. To address these challenges, we have screened the activity of seven new candidates that serve as Paramagnetic Amyloid Ligand (PAL) candidates. PALs are bifunctional small molecules that both remodel the AβO structure and localize a potent antioxidant that mimics the activity of SOD within live cells. The candidates are built from either a stilbene or curcumin scaffold with nitroxyl moiety to serve as catalytic antioxidants. Measurements of PAL AβO binding and remolding along with assessments of bioactivity allow for the extraction of useful SAR information from screening data. One candidate (HO-4450; PMT-307), with a six-membered nitroxyl ring attached to a stilbene ring, displays the highest potency in protecting against cell-derived Aβ. A preliminary low-dose evaluation in AD model mice provides evidence of modest treatment effects by HO-4450. The results for the curcumin PALs demonstrate that the retention of the native curcumin phenolic groups is advantageous to the design of the hybrid PAL candidates. Finally, the PAL remodeling of AβO secondary structures shows a reasonable correlation between a candidate’s bioactivity and its ability to reduce the fraction of antiparallel β-strand. Full article

Global climate change, environmental pollution, and frequent pesticide use severely reduce bee populations, greatly challenging beekeeping. Pesticides such as deltamethrin, a pyrethroid insecticide commonly used to control mosquitoes, can kill individual bees and entire colonies, depending on the exposure. Due to mosquito resistance to pyrethroid insecticides, components that enhance their effect are commonly used. This study explores the potential of Agaricus bisporus mushroom extract in mitigating oxidative stress in bees triggered by pesticides and Nosema ceranae infection. Our findings indicate that A. bisporus extract significantly reduced mortality rates of bees and spore counts of N. ceranae. Furthermore, the extract demonstrated antioxidant properties that lower enzyme activity related to oxidative stress (CAT, SOD, and GST) and MDA concentration, which is linked to lipid peroxidation. These results indicate that natural extracts like A. bisporus can aid bee health by mitigating the effects of pesticides and pathogens on honey bees, thus improving biodiversity. Full article

In this work, NiCo₂O₄ was synthesized from bimetallic oxalate and utilized as a heterogeneous catalyst to active peroxymonosulfate (PMS) for the degradation of tetracycline (TC). The degradation efficiency of TC (30 mg/L) in the NiCo₂O₄ + PMS system reached 92.4%, with NiCo₂O₄ exhibiting satisfactory reusability, stability, and applicability. Radical trapping test and electron paramagnetic resonance (EPR) results indicated that SO₄^•−, •OH, O₂^•−, and ¹O₂ were the dominating reactive oxygen species (ROS) for TC degradation in the NiCo₂O₄ + PMS system. Seven intermediates were identified, and their degradation pathways were proposed. Toxicity assessment using T.E.S.T software (its version is 5.1.1.0) revealed that the identified intermediates had lower toxicity compared to intact TC. A rice seed germination test further confirmed that the NiCo₂O₄ + PMS system effectively degraded TC into low-toxicity or non-toxic products. In conclusion, NiCo₂O₄ shows promise as a safe and efficient catalyst in advanced oxidation processes (AOPs) for the degradation of organic pollutants. Full article

A hierarchical surface that includes objects with different sizes, as a result of creating local fields, initiates a large number of effects. Micropores in the composition of macropores, as well as nanoclusters of the substance, were detected by scanning electron and atomic force microscopies on the surface of ZnO/Por-Si samples. An identical fractal dimension for all levels of the hierarchy was determined for these structures, which is associated with the same response to external excitation. Photoluminescence studies have shown the presence of localized levels in the band gap, with the probability of capturing both electrons and holes, which ensures charge transitions between energy bands. Decomposition of the electron paramagnetic resonance (EPR) signal into components made it possible to determine the manifestations of various types of interaction between paramagnetic particles, including the hyperfine structure of the spectrum. The ordering of the structure of the substance as a result of sequential annealing in the range from 300 to 500 °C was revealed in the EPR spectrum. This fact, as well as photo- and gas sensitivity for all types of samples studied, confirms the prospects of using these structures as sensors. Full article

In this study, the sodium perborate (SP)-activated peroxymonosulfate (PMS) process was used to enhance the coagulation efficiency of cyanobacteria with polymeric aluminum chloride (PAC), aiming to efficiently mitigate the impact of algal blooms on the safety of drinking water production. The optimal concentrations of SP, PMS, and PAC were determined by evaluating the removal rate of OD₆₈₀ and zeta potential of the algae. Experimental results demonstrated that the proposed ternary PMS/SP/PAC process achieved a remarkable OD₆₈₀ removal efficiency of 95.2%, significantly surpassing those obtained from individual treatments with PMS (19.5%), SP (5.2%), and PAC (42.1%), as well as combined treatments with PMS/PAC (55.7%) and PMS/SP (28%). The synergistic effect of PMS/SP/PAC led to the enhanced aggregation of cyanobacteria cells due to a substantial reduction in their zeta potential. Flow cytometry was performed to investigate cell integrity before and after treatment with PMS/SP/PAC. Disinfection by-products (DBPs) (sodium hypochlorite disinfection) of the algae-laden water subsequent to PMS/SP/PAC treatment declined by 57.1%. Moreover, microcystin-LR was completely degraded by PMS/SP/PAC. Electron paramagnetic resonance (EPR) analysis evidenced the continuous production of ${\mathrm{S}\mathrm{O}}_4^{•-}$, •OH, ¹O₂, and ${\mathrm{O}}_2^{•-}$, contributing to both cell destruction and organic matter degradation. This study highlighted the significant potential offered by the PMS/SP/PAC process for treating algae-laden water. Full article

The present review is related to the novel approach for improvement of the optical properties of wide bandgap metal oxides, in particular TiO₂, based on the formation of the inorganic–organic hybrids that display absorption in the visible spectral range due to the formation of interfacial charge transfer (ICT) complexes. We outlined the property requirements of TiO₂-based ICT complexes for efficient photo-induced catalytic reactions, emphasizing the simplicity of the synthetic procedure, the possibility of the fine-tuning of the optical properties supported by the density functional theory (DFT) calculations, and the formation of a covalent linkage between the inorganic and organic components of hybrids, i.e., the nature of the interface. In addition, this study provides a comprehensive insight into the potential applications of TiO₂-based ICT complexes in photo-driven catalytic reactions (water splitting and degradation of organic molecules), including the identification of the reactive species that participate in photocatalytic reactions by the spin-trapping electron paramagnetic resonance (EPR) technique. Considering the practically limitless number of combinations between the inorganic and organic components capable of forming oxide-based ICT complexes and with the knowledge that this research area is unexplored, we are confident it is worth studying, and we emphasized some further perspectives. Full article

Does determinism (or even the incompleteness of quantum mechanics) follow from locality and perfect correlations? In a 1964 paper, John Bell gave the first demonstration that quantum mechanics is incompatible with local hidden variables. Since then, a vigorous debate has rung out over whether he relied on an assumption of determinism or instead, as he later claimed in a 1981 paper, derived determinism from assumptions of locality and perfect correlation. This paper aims to bring clarity to the debate via simple examples and rigorous results. It is first recalled, via quantum and classical counterexamples, that the weakest statistical form of locality consistent with Bell’s 1964 paper (parameter independence) is insufficient for the derivation of determinism. Attention is then turned to critically assess Bell’s appeal to the Einstein–Rosen–Podolsky (EPR) incompleteness argument to support his claim. It is shown that this argument is itself incomplete, via counterexamples that expose two logical gaps. Closing these gaps via a strong “counterfactual” reality criterion enables a rigorous derivation of both determinism and parameter independence, and in this sense justifies Bell’s claim. Conversely, however, it is noted that whereas the EPR argument requires a weaker “measurement choice” assumption than Bell’s demonstration, it nevertheless leads to a similar incompatibility with quantum predictions rather than quantum incompleteness. Full article

Two new 2p–3d complexes, (Et₃NH)[ML(hfac)₂], have been obtained using the nitronyl-nitroxide radical (HL) derived from 2-hydroxy-3-methoxy-5-nitrobenzaldehyde (M = Mn 1; Co 2). The two compounds are isomorphous and their structures consist of anionic mononuclear species, [M(hfac)₂L]⁻, M = Mn 1; Co 2, and triethylammonium cations, Et₃NH⁺. The metal ions adopt an octahedral geometry, being coordinated by phenoxido and aminoxyl oxygen atoms from the ligand and four oxygen atoms from the hexafluoroacetylacetonato (hfac⁻) ligand. The cryomagnetic behaviors of the two compounds reveal relatively strong antiferromagnetic M(II)-Rad interactions (J_MnRad = −191 cm⁻¹, J_CoRad = −166 cm⁻¹ with H = −JS_MS_Rad). The EPR spectra (X- and Q-band) of compound 1 below 70 K show the characteristical features of a S = 2 spin system with zero field splitting terms of D = 0.26 cm⁻¹ and E = 0.031 cm⁻¹. Full article

Gastrointestinal nematode infections are a global concern in grazing cattle production systems, even more so due to the widespread problem of anthelmintic resistance. In response, early anthelmintic resistance detection methods, such as the micro-agar larval development test (MALDT), and parasite management strategies, such as the replacement of resistant parasite populations with susceptible ones, have been developed. This study aimed to characterize ivermectin-susceptible and -resistant isolates of Cooperia spp. using MALDT in the context of a parasite population replacement strategy. Three Cooperia spp. field isolates were evaluated: a susceptible one (Coop-S), a resistant one (Coop-R), and a post-replacement one (Coop-PR). The MALDT was performed in 96-well plates with 12 known concentrations of eprinomectin (EPR) on an agar base. Each test was performed in quadruplicate. Data analysis included nonlinear regression to determine EC50, EC90, and EC99 values, resistance ratios (RRs), and R². The results showed clear differentiation between the isolates, with RR values of 5.78 and 1.28 for Coop-R and Coop-PR, respectively, compared to Coop-S. The MALDT proved to be a reliable tool for differentiating ivermectin-susceptible from ivermectin-resistant isolates of Cooperia spp., and future evaluations of this test in mixed nematode populations are recommended for routine diagnosis of anthelmintic resistance. Full article