35 research outputs found
Inflamm-Aging and Brain Insulin Resistance: New Insights and Role of Life-style Strategies on Cognitive and Social Determinants in Aging and Neurodegeneration
Over the past decades, the human life span has dramatically increased, and therefore, a steady increase in diseases associated with age (such as Alzheimer's disease and Parkinson's disease) is expected. In these neurodegenerative diseases, there is a cognitive decline and memory loss, which accompany increased systemic inflammation, the inflamm-aging, and the insulin resistance. Despite numerous studies of age-related pathologies, data on the contribution of brain insulin resistance and innate immunity components to aging are insufficient. Recently, much research has been focused on the consequences of nutrients and adiposity- and nutrient-related signals in brain aging and cognitive decline. Moreover, given the role of metainflammation in neurodegeneration, lifestyle interventions such as calorie restriction may be an effective way to break the vicious cycle of metainflammation and have a role in social behavior. The various effects of calorie restriction on metainflammation, insulin resistance, and neurodegeneration have been described. Less attention has been paid to the social determinants of aging and the possible mechanism by which calorie restriction might influence social behavior. The purpose of this review is to discuss current knowledge in the interdisciplinary field of geroscience-immunosenescence, inflamm-aging, and metainflammation-which makes a significant contribution to aging. A substantial part of the review is devoted to frontiers in the brain insulin resistance in relation to neuroinflammation. In addition, we summarize new data on potential mechanisms of calorie restriction that influence as a lifestyle intervention on the social brain. This knowledge can be used to initiate successful aging and slow the onset of neurodegenerative diseases
Hydrodechlorination of 4-Chlorophenol on Pd-Fe Catalysts on Mesoporous ZrO2SiO2 Support
A mesoporous support based on silica and zirconia (ZS) was used to prepare monometallic 1 wt% Pd/ZS, 10 wt% Fe/ZS, and bimetallic FePd/ZS catalysts. The catalysts were characterized by TPR-H2, XRD, SEM-EDS, TEM, AAS, and DRIFT spectroscopy of adsorbed CO after H2 reduction in situ and tested in hydrodechlorination of environmental pollutant 4-chlorophelol in aqueous solution at 30 °C. The bimetallic catalyst demonstrated an excellent activity, selectivity to phenol and stability in 10 consecutive runs. FePd/ZS has exceptional reducibility due to the high dispersion of palladium and strong interaction between FeOx and palladium, confirmed by TPR-H2, DRIFT spectroscopy, XRD, and TEM. Its reduction occurs during short-time treatment with hydrogen in an aqueous solution at RT. The Pd/ZS was more resistant to reduction but can be activated by aqueous phenol solution and H2. The study by DRIFT spectroscopy of CO adsorbed on Pd/ZS reduced in harsh (H2, 330 °C), medium (H2, 200 °C) and mild conditions (H2 + aqueous solution of phenol) helped to identify the reasons of the reducing action of phenol solution. It was found that phenol provided fast transformation of Pd+ to Pd0. Pd/ZS also can serve as an active and stable catalyst for 4-PhCl transformation to phenol after proper reduction
THE EFFECT OF DEXTRANAL ON THE GUT BACTERIOBIOME OF CALVES
Background. The search for more efficient pro- and prebiotics to improve calvesâ health, including decreasing the incidence of intestinal infections and increasing biomass production, has been very actual. The effect of prebiotics, however, is poorly, especially as related to gut microbiome biodiversity.Â
The aim of this work was to study the influence of dextranal on the growth of calves and their gut(rectum) bacteriobiome.
Materials and Methods. Bacteriobiome composition and structure was assessed in the control group (K, conventional diet) and dextranal-receiving group (D) in 18-20 days aged calves by 16S metabarcoding (V3-V4, Illumina MiSeq).
Results. Overall, we found 377 operational taxonomic units (OTU) from 168 genera, 91 families, 55 orders, 30 classes and 11 phyla, with more than the half of the total number of identifies OTUs belonging to the Firmicutes phylum, followed by Bacteroidetes and Actinobacteria. The relative abundance of the phylum-specific nucleotide sequences followed the same order of dominance. Dextranal addition resulted in the increased (11.9 kg/calf, or 15%) of the living body mass of the two-months old calves in group D as compared with group K: consequently, the dextranal-related difference in the calvesâ gut bacteriobiome composition and structure can be viewed as beneficial. It primarily concerns the decreased abundance of the opportunistic pathogen Escherichia/Shigella (Gammaproteobacteria) in group D. Overall 73 OTUs, including six dominant ones, were found to be differentially abundant in the groups. However, changes in the relative abundance of some OTUs were difficult to interpret, most likely due to the low strain/species resolution by 16S rRNA gene fragmentsâ sequences. As for the α- biodiversity, there were no differences between the groups, but the overall trend directed to the increasing α- biodiversity of the calvesâ gut bacteriobiome after dextranal treatment.
Conclusion. This study reports the first attempt to inventory the gut bacteriobiome of the cattle in the region, and the obtained results provide the basis for a more detailed and taxonomically targeted further research
Phonon Raman spectra of colloidal CdTe nanocrystals: effect of size, non-stoichiometry and ligand exchange
Resonant Raman study reveals the noticeable effect of the ligand exchange on the nanocrystal (NC) surface onto the phonon spectra of colloidal CdTe NC of different size and composition. The oleic acid ligand exchange for pyridine ones was found to change noticeably the position and width of the longitudinal optical (LO) phonon mode, as well as its intensity ratio to overtones. The broad shoulder above the LO peak frequency was enhanced and sharpened after pyridine treatment, as well as with decreasing NC size. The low-frequency mode around 100 cm-1 which is commonly related with the disorder-activated acoustical phonons appears in smaller NCs but is not enhanced after pyridine treatment. Surprisingly, the feature at low-frequency shoulder of the LO peak, commonly assigned to the surface optical phonon mode, was not sensitive to ligand exchange and concomitant close packing of the NCs. An increased structural disorder on the NC surface, strain and modified electron-phonon coupling is discussed as the possible reason of the observed changes in the phonon spectrum of ligand-exchanged CdTe NCs
Recent Notable Approaches to Study Self-Assembly of Nanoparticles with X-ray Scattering and Electron Microscopy
Self-assembly of nanoparticles (NPs) has evolved into a powerful tool for the synthesis of superstructures with tailored properties. The quality, diversity, and complexity of synthesized structures are continuously improving and fascinating new collective properties are demonstrated. At the same time, the rapid development of electron microscopy and synchrotron sources for X-rays has enabled new exciting experimental approaches to study structure and structure formation in the context of NP self-assembly. In this review, some recent studies and what can be learned from them are highlighted and discussed. It is started with a general introduction covering important concepts, experimental approaches, commonly obtained structures, the ideas of artificial atoms, and emerging properties are discussed. Recent experimental in situ and ex situ approaches with state-of-the-art electron microscopy and X-ray diffraction and scattering that helped to obtain a detailed picture of NP self-assembly processes and resulting structures are then presented
Contact stresses in point frogs
The methodology for calculating the contact stress state for various contact types of frogs and wheel is presented. The magnitudes of contact stresses in the frogs can be calculated according to the Hertz-Belyaev method, taking into account certain evaluating factors
Monitoring Nanocrystal Self-Assembly in Real Time Using In Situ Small-Angle X-Ray Scattering
Selfâassembled nanocrystal superlattices have attracted large scientific attention due to their potential technological applications. However, the nucleation and growth mechanisms of superlattice assemblies remain largely unresolved due to experimental difficulties to monitor intermediate states. Here, the selfâassembly of colloidal PbS nanocrystals is studied in real time by a combination of controlled solvent evaporation from the bulk solution and in situ smallâangle Xâray scattering (SAXS) in transmission geometry. For the first time for the investigated system a hexagonal closedâpacked (hcp) superlattice formed in a solvent vapor saturated atmosphere is observed during slow solvent evaporation from a colloidal suspension. The highly ordered hcp superlattice is followed by a transition into the final bodyâcentered cubic superlattice upon complete drying. Additionally, Xâray crossâcorrelation analysis of Bragg reflections is applied to access information on precursor structures in the assembly process, which is not evident from conventional SAXS analysis. The detailed evolution of the crystal structure with time provides key results for understanding the assembly mechanism and the role of ligandâsolvent interactions, which is important both for fundamental research and for fabrication of superlattices with desired properties
Coexistence of hcp and bct Phases during In Situ Superlattice Assembly from Faceted Colloidal Nanocrystals
We study the in situ self-assembly of faceted PbS nanocrystals from colloidal suspensions upon controlled solvent evaporation using time-resolved small-angle X-ray scattering and X-ray cross-correlation analysis. In our bulk-sensitive experiment in transmission geometry, the superlattice crystallization is observed in real time, revealing a hexagonal closed-packed (hcp) structure followed by formation of a body-centered cubic (bcc) superlattice. The bcc superlattice undergoes continuous tetragonal distortion in the solvated state shortly after its formation, resulting in the body-centered tetragonal (bct) structure. Upon solvent evaporation, the bct superstructure becomes more pronounced with the still coexisting hcp phase. These findings corroborate the existing simulations of assembling cuboctahedral-shaped particles and illustrate that we observed the predicted equilibrium states. This work is essential for a deeper understanding of the fundamental forces that direct nanocrystal assembly including nanocrystal shape and ligand coverage
In situ small-angle X-ray scattering environment for studying nanocrystal self-assembly upon controlled solvent evaporation
We present a sample environment for the investigation of nanoparticle self-assembly from a colloidal solution via controlled solvent evaporation using in situ small-angle X-ray scattering. Nanoparticles form ordered superlattices in the evaporative assembly along the X-ray transparent windows of a three-dimensional sample cell. The special design of the sample cell allows for monitoring the superlattice formation and transformation at different stages of the assembly process during the movement of the evaporation front in real time. The presented sample environment can be used to study the self-organization of a wide range of colloidal particles and other soft materials
Span operational aspects under offsetting the axis of the track panel
The stress-strain state of a small railway bridge with a beam design is considered in the article for the case of offsetting the track panel axis relative to the bridge axis by the value exceeding the limit determined by regulatory documents. The differential equation is considered in the analytical calculation of the behavior parameters and the state of the span under the action of the load. This equation describes the vertical vibrations of the beam and allows considering them as a combination of forced and free vibrations. In numerical modeling, the finite element method is used as the solution procedure. Determining equations of the method contain linear and angular displacements of nodes in the model as unknowns. As a result of the calculations, graphical dependences for normal and horizontal displacements, internal forces, principal and equivalent stresses at various points of the span are obtained. Values are presented that show an increase in bending and torsional forces, as well as in principal stresses when the axis of the railway track is displaced relative to the bridge axis