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Rare earth (RE) addition to steels to produce RE steels has been widely applied when aiming to improve steel properties. However, RE steels have exhibited extremely variable mechanical performances, which has become a bottleneck in the past few decades for their production, utilization and related study. Here in this work, we discovered that the property variation of RE steels stems from the presence of oxygen-based inclusions. We proposed a dual low-oxygen technology, and keeping low levels of oxygen content in steel melts and particularly in the raw RE materials, which have long been ignored, to achieve impressively stable and favourable RE effects. The fatigue life is greatly improved by only parts-per-million-level RE addition, with a 40-fold improvement for the tension-compression fatigue life and a 40% enhancement of the rolling contact fatigue life. We find that RE appears to act by lowering the carbon diffusion rate and by retarding ferrite nucleation at the austenite grain boundaries. Our study reveals that only under very low-oxygen conditions can RE perform a vital role in purifying, modifying and micro-alloying steels, to improve the performance of RE steels.
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Oxigênio , Aço , Ligas , CarbonoRESUMO
Parkinson's disease (P.D.) is the second most progressive neurodegenerative disorder in the elderly. Degeneration of dopaminergic (DA) neurons and α-synuclein (α-Syn) accumulated toxicity is the major contributor to this disease. At present, the disease has no effective treatment. Many recent studies focus on identifying novel therapeutics that provide benefits to stop the disease progression in P.D. patients. Screening novel and effective drugs in P.D. animal models is time- and cost-consuming. Rose Essential Oil (REO) extracted from Rosa Rugosa species (R. Setate × R. Rugosa). REO contains Citronellol, Geraniol, and Octadiene that possess anti-Aß, anti-oxidative, and anti-depression-like properties, but no reports have defined the REO effect on P.D. yet. The present study examines the REO neuroprotective potential in transgenic Caenorhabditis elegans P.D. models. We observed that REO reduced α-Syn aggregations and diminished DA neuron degenerations induced by 6-OHDA, reduced food-sensing behavioural disabilities, and prolonged the lifespan of the nematode. Moreover, REO augmented the chymotrypsin-like proteasome and SOD-3 activities. Further, we observed the anti-oxidative role of REO by reducing internal cells ROS. Together, these findings supported REO as an anti-PD drug and may exert its effects by lowering oxidative stress via the anti-oxidative pathway.
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Óleos Voláteis , Doença de Parkinson , Rosa , Animais , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/patologia , alfa-Sinucleína/metabolismo , alfa-Sinucleína/farmacologia , alfa-Sinucleína/uso terapêutico , Caenorhabditis elegans/metabolismo , Animais Geneticamente Modificados , Óleos Voláteis/farmacologia , Óleos Voláteis/uso terapêutico , Neurônios Dopaminérgicos , Degeneração Neural , Modelos Animais de DoençasRESUMO
ZSM-5 zeolite nanoboxes with accessible meso-micro-pore architecture and strong acid sites are important in relevant heterogeneous catalysis suffering from mass transfer limitations and weak acidities. Rational design of parent zeolites with concentrated and non-protective coordination of Al species can facilitate post-synthetic treatment to produce mesoporous ZSM-5 nanoboxes. In this work, a simple and effective method was developed to convert parent MFI zeolites with tetrahedral extra-framework Al into Al-enriched mesoporous ZSM-5 nanoboxes with low silicon-to-aluminium ratios of ≈16. The parent MFI zeolite was prepared by rapid ageing of the zeolite sol gel synthesis mixture. The accessibility to the meso-micro-porous intra-crystalline network was probed systematically by comparative pulsed field gradient nuclear magnetic resonance diffusion measurements, which, together with the strong acidity of nanoboxes, provided superb catalytic activity and longevity in hydrocarbon cracking for propylene production.
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Parkinson's disease resultant in the degeneration of Dopaminergic neurons and accumulation of α-synuclein in the substantia nigra pars compacta. The synthetic therapeutics for Parkinson's disease have moderate symptomatic benefits but cannot prevent or delay disease progression. In this study, nicotine was employed by using transgenic Caenorhabditis elegans Parkinson's disease models to minimize the Parkinson's disease symptoms. The results showed that the nicotine at 100, 150, and 200 µM doses reduced degeneration of Dopaminergic neurons caused by 6-hydroxydopamine (14, 33, and 40%), lowered the aggregative toxicity of α-synuclein by 53, 56, and 78%, respectively. The reduction in food-sensing behavioral disabilities of BZ555 was observed to be 18, 49, and 86%, respectively, with nicotine concentrations of 100 µM, 150 µM, and 200 µM. Additionally, nicotine was found to enhance Daf-16 nuclear translocation by 14, 31, and 49%, and dose-dependently increased SOD-3 expression by 10, 19, and 23%. In summary, the nicotine might a promising therapy option for Parkinson's disease.
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This work presents the development and systematic study of a method to prepare hierarchical titanium silicalite-1 (TS-1) zeolites with high tetra-coordinated framework Ti species content. The new method involves (i) the synthesis of the aged dry gel by treating the zeolite precursor at 90 °C for 24 h; and (ii) the synthesis of hierarchical TS-1 by treating the aged dry gel using tetrapropylammonium hydroxide (TPAOH) solution under hydrothermal conditions. Systematic studies were conducted to understand the effect of the synthesis conditions (including the TPAOH concentration, liquid-to-solid ratio, and treatment time) on the physiochemical properties of the resulting TS-1 zeolites, and the results showed that the condition of a TPAOH concentration of 0.1 M, liquid-to-solid ratio of 1.0, and treatment time of 9 h was ideal to enable the synthesis of hierarchical TS-1 with a Si/Ti ratio of 44. Importantly, the aged dry gel was beneficial to the quick crystallization of zeolite and assembly of nanosized TS-1 crystals with a hierarchical structure (S ext = 315 m2 g-1 and V meso = 0.70 cm3 g-1, respectively) and high framework Ti Species content, making the accessible active sites ready for promoting oxidation catalysis.
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The development of affordable and compact noninvasive point-of-care (POC) dopamine biosensors for the next generation is currently a major and challenging problem. In this context, a highly sensitive, selective, and low-cost sensing probe is developed by a simple one-step laser-scribing process of plastic waste. A flexible POC device is developed as a prototype and shows a highly specific response to dopamine in the real sample (urine) as low as 100 pmol/L in a broad linear range of 10-10-10-4 mol/L. The 3D topological feature, carrier kinetics, and surface chemistry are found to improve with the formation of high-density metal-embedded graphene-foam composite driven by laser irradiation on the plastic-waste surface. The development of various kinds of flexible and tunable biosensors by plastic waste is now possible thanks to the success of this simple, but effective, laser-scribing technique, which is capable of modifying the matrix's electronic and chemical composition.
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Líquidos Corporais , Dopamina , Eletrônica , Lasers , PlásticosRESUMO
Parkinson disease (PD) is the second most progressive neurodegenerative disorder of the central nervous system (CNS) in the elderly, causing motor impediments and cognitive dysfunctions. Dopaminergic (DA) neuron degeneration and α-synuclein (α-Syn) accumulation in substantia nigra pars compacta (SNPc) are the major contributor to this disease. At present, the disease has no effective treatment. Many recent studies focus on identifying novel therapeutics that provide benefits to stop disease advancement in PD patients. Cannabidiol (CBD) is a cannabinoid derived from the Cannabis sativa plant and possesses anti-depressive, anti-inflammatory, and antioxidative effects. The present study aims to evaluate the neuroprotective effect of CBD in transgenic C. elegans PD models. We observed that CBD at 0.025 mM (24.66 %), 0.05 mM (52.41 %) and 0.1 mM (71.36 %) diminished DA neuron degenerations induced by 6-hydroxydopamine (6-OHDA), reduced (0.025, 27.1 %), (0.05, 38.9 %), (0.1, 51.3 %) food-sensing behavioural disabilities in BZ555, reduced 40.6 %, 56.3 %, 70.2 % the aggregative toxicity of α-Syn and expanded the nematodes' lifespan up to 11.5 %, 23.1 %, 28.8 %, dose-dependently. Moreover, CBD augmented the ubiquitin-like proteasomes 28.11 %, 43.27, 61.33 % and SOD-3 expressions by about 16.4 %, 21.2 %, 44.8 % in transgenic models. Further, we observed the antioxidative role of CBD by reducing 33.2 %, 41.4 %, 56.7 % reactive oxygen species in 6-OHDA intoxicated worms. Together, these findings supported CBD as an anti-parkinsonian drug and may exert its effects by raising lipid depositions to enhance proteasome activity and reduce oxidative stress via the antioxidative pathway.
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Canabidiol , Fármacos Neuroprotetores , Doença de Parkinson , Animais , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Caenorhabditis elegans , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Fármacos Neuroprotetores/metabolismo , Oxidopamina , Canabidiol/farmacologia , Canabidiol/uso terapêutico , Neurônios Dopaminérgicos , Dopamina/metabolismo , Antioxidantes/metabolismo , Modelos Animais de DoençasRESUMO
ε-Iron nitrides with the general formula ε-Fe3N1+x (-0.40 < x < 0.48) have been widely studied due to their interesting magnetism. However, the phase diagram of the Fe-N binary system indicates the absence of monophasic ε-Fe3N1+x (x < 0) compounds that are stable below their synthetic temperatures. Here, ε-Fe3N1+x (-0.12 ≤ x ≤ -0.01) nanoparticles with excellent thermal stability and magnetic properties were synthesized by a simple chemical solution method. The ε-Fe3N1+x nanoparticles with space group P6322 have excellent oxidation resistance due to a carbon shell with a thickness of 2-3 nm. NPD refinements suggest that the ε-Fe3N1+x nanoparticles possess a highly ordered arrangement of N atoms and their magnetic moments align parallel to the c axis. The Curie temperature (TC) and room temperature saturation magnetization (MS) increase with decreasing N content, which results in record-high TC (632 K) and MS (169.2 emu g-1) at x = -0.12, much higher than the magnetic properties of the corresponding bulk materials. The significant enhancements in the intrinsic magnetic properties and thermal stability of ε-Fe3N1+x are ascribed to chemically engineering the stoichiometry and N occupancy from the disordered to the ordered site.
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Hematite (α-Fe2O3) is a red material with a band gap of about 2.0 eV, which indicates that it can absorb more solar light. It is a promising photocatalyst applied in many fields. In this paper, α-Fe2O3 single crystal hollow hexagonal bipyramids were synthesized by a simple one-pot hydrothermal method. The morphology and structure of the prepared α-Fe2O3 hollow hexagonal bipyramids were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The hollow single crystals show a good light absorption and performance in photodegradation of methylene blue (MB). Due to the strategy of depositing ultra-thin layers of Al2O3 by atomic layer deposition (ALD), the photoelectrochemical (PEC) performance of α-Fe2O3 under the simulated solar light irradiation is also improved.