Search results for "Branes"

Influence of electrodeposition techniques on Ni nanostructures

2008

Abstract Different Ni nanostructure arrays were fabricated by pulsed electrodeposition from a Watts bath inside the pores of anodic alumina membrane (AAM) templates. Under a trapezoidal waveform of potential, consisting of fast linear sweeps between 0 and −3 V (SCE) interleaved by delay times at 0 (10 s) and −3 V (0.1 s), Ni nanowires were grown. The rate of nanowires growth was constant up to 60 min of deposition. For longer times, the growth of nanowires was not uniform, and after about 180 min some nanowires reached the template surface exposed to the electrolyte. Under square potential pulses between the same potentials (pulse length 1 s), nanotubes of Ni are obtained. Morphological ana…

Electrochemical synthesis and characterization of self-standing metal oxide nanostructures

2009

Nanostructures Fabrication by Template Deposition in Anodic Alumina Membranes

2009

Raman spectroscopy of lead dioxide nanowires

2009

EFFECT OF MICROENCAPSULATION ON OXYGEN DISTRIBUTION IN ISLETS ORGANS

1994

In islet transplantation, limitation of oxygen supply may restrict graft function, particularly when encapsulated tissue is used. Therefore, oxygen tensions (PO2) in isolated islet organs (Brockmann bodies) of Osphronemus gorami were measured. In a thermostatically (37 degrees C) controlled measuring chamber, PO2 values were recorded at subsequent microelectrode positions on a radial track toward the center of the organ. In 2 independent groups, we studied the effect of fluid convection (n = 12) and microencapsulation (n = 12). In both groups, sigmoidal PO2 profiles were found, which permit differentiation in an oxygen-depleted zone surrounding the surface, a steep decline inside the tissue…

Extracellular Membrane Vesicles as Vehicles for Brain Cell-to-Cell Interactions in Physiological as well as Pathological Conditions.

2015

Extracellular vesicles are involved in a great variety of physiological events occurring in the nervous system, such as cross talk among neurons and glial cells in synapse development and function, integrated neuronal plasticity, neuronal-glial metabolic exchanges, and synthesis and dynamic renewal of myelin. Many of these EV-mediated processes depend on the exchange of proteins, mRNAs, and noncoding RNAs, including miRNAs, which occurs among glial and neuronal cells. In addition, production and exchange of EVs can be modified under pathological conditions, such as brain cancer and neurodegeneration. Like other cancer cells, brain tumours can use EVs to secrete factors, which allow escaping…

The influence of solid retention time on IFAS-MBR systems: analysis of system behavior.

2018

A University of Cape Town Integrated Fixed-Film Activated Sludge Membrane Bioreactor (UCT-IFAS-MBR) pilot plant was operated at different values of the sludge retention time (SRT). Three SRTs were investigated at different durations: indefinitely, 30 and 15 days. The organic carbon, nitrogen and phosphorus removal, kinetic/stoichiometric parameters, membrane fouling tendency and sludge filtration properties were assessed. The findings showed that by decreasing the SRT, the pilot plant could maintain excellent carbon removal efficiencies throughout the experiments. In contrast, the biological carbon removal showed a slight nitrification and was slightly affected by the decrease of the SRT, s…

Freeze-fracture features of epithelioid cells, multinucleated giant cells, and phagocytic macrophages

1987

The freeze-fracture morphology of epithelioid cells, multinucleated giant cells (Langhans' type), and phagocytic macrophages was investigated. The intensely folded and interdigitating surface membranes of epithelioid cells and multinucleated giant cells displayed no specialized areas of cell contact. The size of the intramembranous particles (IMP) and the fact that the area density of IMPs was higher in the cytoplasmic (P) faces than in the external (E) faces of the cell membranes agreed with observations in other eukaryotic cells. The area densities of the IMPs suggest lower transport rates of molecules across the cell membranes of granuloma cells than of certain epithelial cells. Small pi…

Gravity-mediated dark matter in clockwork/linear dilaton extra-dimensions

2020

We study for the first time the possibility that Dark Matter (represented by particles with spin $0,1/2$ or $1$) interacts gravitationally with Standard Model particles in an extra-dimensional Clockwork/Linear Dilaton model. We assume that both, the Dark Matter and the Standard Model, are localized in the IR-brane and only interact via gravitational mediators, namely the Kaluza-Klein (KK) graviton and the radion/KK-dilaton modes. We analyse in detail the Dark Matter annihilation channel into Standard Model particles and into two on-shell Kaluza-Klein towers (either two KK-gravitons, or two radion/KK-dilatons, or one of each), finding that it is possible to obtain the observed relic abundanc…

Magnetic resonance imaging of dissolved hyperpolarized 129Xe using a membrane-based continuous flow system.

2009

Abstract A technique for continuous production of solutions containing hyperpolarized 129Xe is explored for MRI applications. The method is based on hollow fiber membranes which inhibit the formation of foams and bubbles. A systematic analysis of various carrier agents for hyperpolarized 129Xe has been carried out, which are applicable as contrast agents for in vivo MRI. The image quality of different hyperpolarized Xe solutions is compared and MRI results obtained in a clinical as well as in a nonclinical MRI setting are provided. Moreover, we demonstrate the application of 129Xe contrast agents produced with our dissolution method for lung MRI by imaging hyperpolarized 129Xe that has been…