997 research outputs found
Survival and Growth of Adult Human Oligodendrocytes in Culture: Scanning Electron Microscopy
The oligodendrocytes in culture serve as an important model for the study of demyelination diseases. We have previously originated a method of isolating human oligodendrocytes. In order to establish their three dimensional morphology, scanning electron microscopy of the cultured oligodendrocytes was performed.
The oligodendrocytes bulk isolated from adult human brain were maintained in culture for more than 2 months. At the various periods in culture, the cells were studied by scanning electron microscopy and immunofluorescence staining using marker antibodies for the identification of oligodendrocytes. The three dimensional organization and the surface morphology of the cultured oligodendrocytes were investigated. They displayed an extensive network of the cell processes and characteristic surface morphology
Application of agent-based modeling and simulation to understanding complex management problems in CEM research
As construction projects have become larger and more complex, they develop different features than smaller or traditional projects, which characterize them as complex systems. Still, Construction Engineering and Management (CEM) researchers have mostly relied on traditional approaches to investigate complex management problems, which might produce misleading results. This paper introduces Agent-Based Modeling and Simulation (ABMS) as a research method, and addresses how it could be applied to CEM research. With an illustrative example of the application of ABMS to CEM research, the theoretical background as well as the design, development, and test processes of ABMS are presented. We then made a recommendation on the promising research subjects in CEM area to which ABMS could be suitably applied
Piezo-tolerant natural gas-producing microbes under accumulating pCO2
<p>Background: It is known that a part of natural gas is produced by biogenic degradation of organic matter, but the microbial pathways resulting in the formation of pressurized gas fields remain unknown. Autogeneration of biogas pressure of up to 20 bar has been shown to improve the quality of biogas to the level of biogenic natural gas as the fraction of CO2 decreased. Still, the pCO2 is higher compared to atmospheric digestion and this may affect the process in several ways. In this work, we investigated the effect of elevated pCO2 of up to 0.5 MPa on Gibbs free energy, microbial community composition and substrate utilization kinetics in autogenerative high-pressure digestion. Results: In this study, biogas pressure (up to 2.0 MPa) was batch-wise autogenerated for 268 days at 303 K in an 8-L bioreactor, resulting in a population dominated by archaeal Methanosaeta concilii, Methanobacterium formicicum and Mtb. beijingense and bacterial Kosmotoga-like (31% of total bacterial species), Propioniferax-like (25%) and Treponema-like (12%) species. Related microorganisms have also been detected in gas, oil and abandoned coal-bed reservoirs, where elevated pressure prevails. After 107 days autogeneration of biogas pressure up to 0.50 MPa of pCO2, propionate accumulated whilst CH4 formation declined. Alongside the Propioniferax-like organism, a putative propionate producer, increased in relative abundance in the period of propionate accumulation. Complementary experiments showed that specific propionate conversion rates decreased linearly from 30.3 mg g−1 VSadded day−1 by more than 90% to 2.2 mg g−1 VSadded day−1 after elevating pCO2 from 0.10 to 0.50 MPa. Neither thermodynamic limitations, especially due to elevated pH2, nor pH inhibition could sufficiently explain this phenomenon. The reduced propionate conversion could therefore be attributed to reversible CO2-toxicity. Conclusions: The results of this study suggest a generic role of the detected bacterial and archaeal species in biogenic methane formation at elevated pressure. The propionate conversion rate and subsequent methane production rate were inhibited by up to 90% by the accumulating pCO2 up to 0.5 MPa in the pressure reactor, which opens opportunities for steering carboxylate production using reversible CO2-toxicity in mixed-culture microbial electrosynthesis and fermentation.</p
Dissolution of Spinel Oxides and Capacity Losses in 4 V Li/LixMn2O4 Cells
Dissolution of spinel manganese oxides and the concomitant cathodic capacity losses were examined in 4 V Li/PC +
DME + LiClO4/LiMn2O4 cells where PC is propylene carbonate and DME is dimethoxyethane. Dissolved Mn2 contents
in the electrolytes were analyzed as a function of cathode potential and carbon contents in the composite cathodes.
Characteristically, manganese dissolution was notably high at the charged state (at >4.1 V vs. Li/Lit), in which potential
range an electrochemical oxidation of the solvent molecules was also prominent. From this and another observation
whereby the Mn dissolution increased with increasing carbon content in the composite cathodes, it was proposed that, at
the charged state of the cathode the solvent molecules are electrochemically oxidized on carbon surfaces and an as-generated
species promotes the manganese dissolution. Results of an ac impedance study revealed that Mn dissolution brings
about an increase in contact resistances at the Mn-depleted spinel/carbon interface, and also in the electrode reaction
resistances for Li intercalation/deintercalation. Thus, the Mn dissolution causes capacity losses in two different pathways;
material loss of the loaded spinel and polarization loss due to a cell resistance increment. The former prevailed
when cathodes contained excess amounts of carbon, while the latter became more of a problem as the carbon contents
decreased
CVD-grown monolayer MoS2 in bioabsorbable electronics and biosensors
Transient electronics entails the capability of electronic components to dissolve or reabsorb in a controlled manner when used in biomedical implants. Here, the authors perform a systematic study of the processes of hydrolysis, bioabsorption, cytotoxicity and immunological biocompatibility of monolayer MoS2
Electrical spin injection and accumulation in CoFe/MgO/Ge contacts at room temperature
We first report the all-electrical spin injection and detection in
CoFe/MgO/moderately doped n-Ge contact at room temperature (RT), employing
threeterminal Hanle measurements. A sizable spin signal of ~170 k{\Omega}
{\mu}m^2 has been observed at RT, and the analysis using a single-step
tunneling model gives a spin lifetime of ~120 ps and a spin diffusion length of
~683 nm in Ge. The observed spin signal shows asymmetric bias and temperature
dependences which are strongly related to the asymmetry of the tunneling
process.Comment: 28 pages, 5 figure
Growth direction determination of a single RuO2 nanowire by polarized Raman spectroscopy
The dependence of band intensities in the Raman spectrum of individual single-crystal ruthenium dioxide (RuO2) nanowires on the angle between the plane of polarization of the exciting (and collected) light and the long axis of the nanowire, is shown to be a simple, complementary technique to high resolution transmission electron microscopy (HRTEM) for determining nanowire growth direction. We show that excellent agreement exists between what is observed and what is predicted for the polarization angle dependence of the intensities of the nanowires' E-g (525 cm(-1)) and the B-2g (714 cm(-1)) Raman bands, only by assuming that the nanowires grow along the (001) crystallographic direction, as confirmed by HRTEM.open9
Exosomes from Human Adipose Tissue-Derived Mesenchymal Stem Cells Promote Epidermal Barrier Repair by Inducing de Novo Synthesis of Ceramides in Atopic Dermatitis.
Atopic dermatitis (AD) is a multifactorial, heterogeneous disease associated with epidermal barrier disruption and intense systemic inflammation. Previously, we showed that exosomes derived from human adipose tissue-derived mesenchymal stem cells (ASC-exosomes) attenuate AD-like symptoms by reducing multiple inflammatory cytokine levels. Here, we investigated ASC-exosomes' effects on skin barrier restoration by analyzing protein and lipid contents. We found that subcutaneous injection of ASC-exosomes in an oxazolone-induced dermatitis model remarkably reduced trans-epidermal water loss, while enhancing stratum corneum (SC) hydration and markedly decreasing the levels of inflammatory cytokines such as IL-4, IL-5, IL-13, TNF-α, IFN-γ, IL-17, and TSLP, all in a dose-dependent manner. Interestingly, ASC-exosomes induced the production of ceramides and dihydroceramides. Electron microscopic analysis revealed enhanced epidermal lamellar bodies and formation of lamellar layer at the interface of the SC and stratum granulosum with ASC-exosomes treatment. Deep RNA sequencing analysis of skin lesions demonstrated that ASC-exosomes restores the expression of genes involved in skin barrier, lipid metabolism, cell cycle, and inflammatory response in the diseased area. Collectively, our results suggest that ASC-exosomes effectively restore epidermal barrier functions in AD by facilitating the de novo synthesis of ceramides, resulting in a promising cell-free therapeutic option for treating AD
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