Stevia has been shown to prevent oxidative stress and inflammation in carbon tetrachloride‐induced cirrhosis models. This study aimed to investigate the ability of an aqueous extract of stevia (AES) ...to prevent thioacetamide (TAA)‐induced cirrhosis in rats and to explore its mechanism of action. Liver cirrhosis was established by administering TAA (200 mg/kg by i.p. injections three times a week for 10 weeks); AES was administered (100 mg/kg by gavage daily) during the TAA treatment. Liver damage and fibrosis were evaluated, and the profibrotic pathways were analyzed by western blotting and immunohistochemistry. TAA increased nuclear factor kappa B (NF‐κB) and pro‐inflammatory cytokine production, as well as the malondialdehyde and 4‐hydroxynonenal levels, whereas the glutathione/glutathione disulfide and nuclear factor‐E2‐related factor 2 (Nrf2) levels were decreased. Moreover, TAA increased collagen production, hepatic stellate cell (HSC) activation, and expression of profibrogenic mediators. TAA‐treated rats that had been exposed to Mn2+ exhibited altered striatal dopamine turnover, indicating hepatic encephalopathy. AES partially or completely prevented all of these effects. AES showed antioxidant, anti‐inflammatory, and antifibrotic properties, probably because of its capacity to induce Nrf2 expression, reduce NF‐κB expression, and block several profibrogenic signaling pathways, subsequently inhibiting HSC activation and preventing fibrosis and dopamine turnover.
Magnetron‐sputtering inert‐gas condensation is an emerging technique offering single‐step, chemical‐free synthesis of nanoparticles with well‐defined morphologies optimized for specific applications. ...In this study, the authors report a flexible approach to produce Fe nanocubes as building blocks for high‐performance NO2 gas sensor devices, and hybrid FeAu nanocubes with magneto‐plasmonic properties. Considering that nucleation happens within a short distance from the sputtering target, the authors utilize the high‐permeability and resultant screening effect induced by magnetic Fe targets of various thicknesses to manipulate the magnetic field configuration and plasma confinement. The authors thus readily switch from bimodal to single‐Gaussian size distributions of Fe nanocubes by modifying their primordial thermal environments, as explained by a combination of modeling methods. Simultaneously, the authors obtain a material yield increase of more than one order of magnitude compared to experiments using postgrowth mass filtration. The effectiveness of the method is demonstrated by the deposition of Fe nanocubes on microhotplate devices, leading to unprecedented NO2 detection performance for Fe‐based chemoresistive gas sensors. The exceedingly low detection limit down to 3 ppb is attributed to a morphological change in operando from Fe/Fe‐oxide core/shell to specific hollow‐nanocube structures, as revealed by in situ environmental transmission electron microscopy.
A flexible gas‐phase synthesis method is demonstrated for the fabrication of multifunctional hybrid Fe nanocubes by means of morphological control during formation. Utilizing this approach, magneto‐plasmonic properties of Fe nanocubes are tailored by Au‐doping, and Fe‐based gas sensors are realized with remarkable performance for NO2 detection down to concentrations as low as 3 ppb.
We investigate the aerobic oxidation of high-pressure, high-temperature nanodiamonds (5–50 nm dimensions) using a combination of carbon and oxygen K-edge X-ray absorption, wavelength-dependent X-ray ...photoelectron, and vibrational spectroscopies. Oxidation at 575 °C for 2 h eliminates graphitic carbon contamination (>98%) and produces nanocrystals with hydroxyl functionalized surfaces as well as a minor component (<5%) of carboxylic anhydrides. The low graphitic carbon content and the high crystallinity of HPHT are evident from Raman spectra acquired using visible wavelength excitation (λexcit = 633 nm) as well as carbon K-edge X-ray absorption spectra where the signature of a core–hole exciton is observed. Both spectroscopic features are similar to those of chemical vapor deposited (CVD) diamond but differ significantly from the spectra of detonation nanodiamond. The importance of these findings to the functionalization of nanodiamond surfaces for biological labeling applications is discussed.
Retinoic acid (RA) plays major roles during nervous system development, and during regeneration of the adult nervous system. We have previously shown that components of the RA signaling pathway are ...upregulated after optic nerve injury, and that exogenous application of all-trans retinoic acid (ATRA) greatly increases the survival of axotomized retinal ganglion cells (RGCs). The objective of the present study is to investigate the effects of ATRA application on the macrophages in the optic nerve after injury, and to determine whether this affects axonal regeneration. The optic nerve was crushed and treated with PBS, ATRA and/or clodronate-loaded liposomes. Nerves were examined at one and two weeks after axotomy with light microscopy, immunocytochemistry and electron microscopy. ATRA application to the optic nerve caused transient increases in the number of macrophages and microglia one week after injury. The macrophages are consistently labeled with M2-type markers, and have considerable phagocytic activity. ATRA increased ultrastructural features of ongoing phagocytic activity in macrophages at one and two weeks. ATRA treatment also significantly increased the numbers of regenerating GAP-43-labeled axons. Clodronate liposome treatment depleted macrophage numbers by 80%, completely eliminated the ATRA-mediated increase in axonal regeneration, and clodronate treatment alone decreased axonal numbers by 30%. These results suggest that the success of axon regeneration is partially dependent on the presence of debris-phagocytosing macrophages, and that the increases in regeneration caused by ATRA are in part due to their increased numbers. Further studies will examine whether macrophage depletion affects RGC survival.
The design of functional interfaces is central to both fundamental and applied research in materials science and energy technology. We introduce a new, broadly applicable technique for the precisely ...controlled high‐throughput preparation of well‐defined interfaces containing polyatomic species ranging from small ions to nanocrystals and large protein complexes. The mass‐dispersive deposition of ions onto surfaces is achieved using a rotating‐wall mass analyzer, a compact device which enables the separation of ions using low voltages and has a theoretically unlimited mass range. We demonstrate an efficient deposition of singly charged Au144(SC4H9)60 ions (33.7 kDa), which opens up exciting opportunities for the structural characterization of nanocrystals and their assemblies using transmission electron microscopy. Our approach also enables the high‐throughput deposition of mass‐selected ions from multicomponent mixtures, which is of interest to the controlled preparation of surface gradients and rapid screening of molecules in mixtures for a specific property.
You spin me round: Preparative mass spectrometry using a rotating‐wall mass analyzer enables the deposition of well‐defined polyatomic ions from small molecules to nanoclusters and protein complexes as well as the high‐throughput separation and deposition of molecules from multicomponent mixtures. The approach is of interest to the design and preparation of functional interfaces and uses an inexpensive and compact instrumentation.
We report a facile single-step synthesis of ternary hybrid nanoparticles (NPs) composed of multiple dumbbell-like iron-silver (FeAg) cores encapsulated by a silicon (Si) shell using a versatile ...co-sputter gas-condensation technique. In comparison to previously reported binary magneto-plasmonic NPs, the advantage conferred by a Si shell is to bind the multiple magneto-plasmonic (FeAg) cores together and prevent them from aggregation at the same time. Further, we demonstrate that the size of the NPs and number of cores in each NP can be modulated over a wide range by tuning the experimental parameters.
Objetivo: Describir las características epidemiológicas de los traumatismos oculares atendidos en el Instituto Regional de Oftalmología (IRO). Materiales y métodos: Estudio descriptivo y prospectivo, ...en el cual se aplicó un protocolo estandarizado de registro de datos demográficos y clínicos de pacientes con traumatismos oculares que acudieron al servicio de emergencia del IRO, entre enero 2016 y abril 2017. Resultados: Un total de 1 288 pacientes cumplieron los criterios de selección, la edad promedio fue de 37 años, en su mayoría los afectados fueron varones (84,7 %) y el grupo etario más afectado fue el de 21 a 40 años (46,7 %). Los accidentes laborales fueron la causa más frecuente (63,7 %), ocurriendo principalmente en trabajadores de metalmecánica, construcción y albañilería; seguido de los accidentes domésticos (19,2 %). El 95,4 % fueron traumatismos cerrados, predominantemente con compromiso unilateral, ocupando el primer lugar los cuerpos extraños corneales (73,4 %), seguido de las contusiones (16,2 %). El 56,2 % de traumatismos abiertos fueron penetrantes restringiéndose el daño principalmente a la córnea (64,9 %). El 52,6 % de pacientes con traumatismo abierto terminaron con agudeza visual entre 4/200 y no percepción de luz. Conclusiones: Los traumatismos oculares cerrados fueron los más frecuentes y afectaron a pacientes jóvenes, de sexo masculino que laboraban en industria metalmecánica y construcción; siendo los cuerpos extraños corneales metálicos el principal tipo. La mayoría de los traumatismos abiertos tuvieron un pobre pronóstico visual luego de su reparación quirúrgica.
Mucor circinelloides is one of the causal agents of mucormycosis, an emerging and high mortality rate fungal infection produced by asexual spores (sporangiospores) of fungi that belong to the order ...Mucorales. M. circinelloides has served as a model genetic system to understand the virulence mechanism of this infection. Although the G-protein signaling cascade plays crucial roles in virulence in many pathogenic fungi, its roles in Mucorales are yet to be elucidated. Previous study found that sporangiospore size and calcineurin are related to the virulence in Mucor, in which larger spores are more virulent in an animal mucormycosis model and loss of a calcineurin A catalytic subunit CnaA results in larger spore production and virulent phenotype. The M. circinelloides genome is known to harbor twelve gpa (gpa1 to gpa12) encoding G-protein alpha subunits and the transcripts of the gpa11 and gpa12 comprise nearly 72% of all twelve gpa genes transcript in spores. In this study we demonstrated that loss of function of Gpa11 and Gpa12 led to larger spore size associated with reduced activation of the calcineurin pathway. Interestingly, we found lower levels of the cnaA mRNAs in sporangiospores from the Δgpa12 and double Δgpa11/Δgpa12 mutant strains compared to wild-type and the ΔcnaA mutant had significantly lower gpa11 and gpa12 mRNA levels compared to wild-type. However, in contrast to the high virulence showed by the large spores of ΔcnaA, the spores from Δgpa11/Δgpa12 were avirulent and produced lower tissue invasion and cellular damage, suggesting that the gpa11 and gpa12 define a signal pathway with two branches. One of the branches controls spore size through regulation of calcineurin pathway, whereas virulences is controlled by an independent pathway. This virulence-related regulatory pathway could control the expression of genes involved in cellular responses important for virulence, since sporangiospores of Δgpa11/Δgpa12 were less resistant to oxidative stress and phagocytosis by macrophages than the ΔcnaA and wild-type strains. The characterization of this pathway could contribute to decipher the signals and mechanism used by Mucorales to produce mucormycosis.
Single-atom functionalization of transition-metal dichalcogenide (TMD) nanosheets is a powerful strategy to tune the optical, magnetic, and catalytic properties of two-dimensional materials. In this ...work, we demonstrate a simple solution-phase method to generate nucleophilic sulfide sites on colloidal WS
nanosheets that subsequently serve as ligands for Ni single atoms. These materials can be controllably functionalized with varying amounts of Ni on the surface ranging from 9% to 47% coverage with respect to W. High-resolution scanning transmission electron microscopy coupled to electron energy loss spectroscopy and X-ray absorption spectroscopy indicate that adsorbed Ni species bind as single atoms at low coverage and a mixture of single atoms and multimetallic clusters at high coverage. The Ni single atoms adsorbed on WS
show altered electronic properties, and both the electronic perturbation and isolated atom geometry play a role in enhancing the intrinsic catalytic activity of Ni-WS
samples for the electrochemical oxygen evolution reaction.
PDF
