Search results for "nanotechnology"
showing 10 items of 9818 documents
Hydrogen Bonding in Amorphous Alkaline Earth Carbonates
2018
Amorphous intermediates play a crucial role during the crystallization of alkaline earth carbonates. We synthesized amorphous carbonates of magnesium, calcium, strontium, and barium from methanolic solution. The local environment of water and the strength of hydrogen bonding in these hydrated modifications were probed with Fourier transform IR spectroscopy,
Novel supramolecular affinity materials based on (−)-isosteviol as molecular templates
2013
The readily available ex-chiral-pool building block (−)-isosteviol was combined with the C3-symmetric platforms hexahydroxytriphenylene and hexaaminotriptycene providing large and rigid molecular architectures. Because of the persistent cavities these scaffolds are very potent supramolecular affinity materials for head space analysis by quartz crystal microbalances. The scaffolds serve in particular as templates for tracing air-borne arenes at low concentration. The affinities of the synthesized materials towards different air-borne arenes were determined by 200 MHz quartz crystal microbalances.
Biodistribution of Insulin-Nanogels in Mouse: A Preliminary Study for the Treatment of Alzheimer's Disease
2017
A growing body of evidence shows that Insulin, Insulin Receptor (IR) and IR signaling are involved in brain cognitive functions and their dysfunction is implicated in Alzheimer's disease (AD) neurodegeneration. Thus, administration of insulin could be a strategy for AD treatment. For this aim we have designed, synthesized and characterized a nanogel system (NG) that has been conjugated to insulin molecules (NG-In) to deliver the protein into the brain, as a tool for the development of a new therapy against AD. In our preclinical study in mice, intraperitoneal injection of fluorescent-labeled NG has allowed to determine the biodistribution of NG vs time in the whole body and its clearance th…
Increased carrier peptide stability through ph adjustment improves insulin and pth(1-34) delivery in vitro and in vivo rather than by enforced carrie…
2020
Oral delivery of therapeutic peptides is hampered by their large molecular size and labile nature, thus limiting their permeation across the intestinal epithelium. Promising approaches to overcome the latter include co-administration with carrier peptides. In this study, the cell-penetrating peptide penetratin was employed to investigate effects of co-administration with insulin and the pharmacologically active part of parathyroid hormone (PTH(1-34)) at pH 5, 6.5, and 7.4 with respect to complexation, enzymatic stability, and transepithelial permeation of the therapeutic peptide in vitro and in vivo. Complex formation between insulin or PTH(1-34) and penetratin was pH-dependent. Micron-size…
Octave Spanning Supercontinuum in Titanium Dioxide Waveguides
2018
International audience; We report on the experimental generation of an octave-spanning supercontinuum in a 2.2 cm-long titanium dioxide optical waveguide with two zero dispersion wavelengths. The resulting on-chip supercontinuum reaches the visible wavelength range as well as the mid-infrared region by using a femtosecond fiber laser pump at 1.64 µm.
Simulation of Fatigue Delamination Growth in Composites with Different Mode Mixtures
2007
A numerical model, obtained by implementing a cyclic damage model in the framework of an interface element, is here proposed to reproduce the crack growth in laminated composites subjected to cyclically repeated loads. This model, which differs from the few studies in the literature on the topic, applies not only to single fracture modes but also to mixed modes, and to constant or variable crack growth rates. The applied load (in terms of force or displacement) is assumed to oscillate between a minimum and a maximum constant value. The Paris curve can be reproduced with accuracy once some parameters in the numerical model are tuned with experiments. These parameters are preliminarily found…
The effect of Ag, Pb and Bi impurities on grain boundary sliding and intergranular decohesion in Copper
2016
We investigate the changes in grain boundary sliding (GBS) and intergranular decohesion in copper (Cu), due to the inclusion of bismuth (Bi), lead (Pb) and silver (Ag) substitutional impurity atoms at a $\Sigma$5 (0 1 2) symmetric tilt grain boundary (GB), using a first-principles concurrent multiscale approach. We first study the segregation behavior of the impurities by determining the impurity segregation energy in the vicinity of the GB. We find that the energetically preferred sites are on the GB plane. We investigate the intergranular decohesion of Cu by Bi and Pb impurities and compare this to the effect of Ag impurities by considering the work of separation, $W_s$ and the tensile st…
Gas-Phase Hydrogenation of Propionitrile Catalyzed by LnCu2 (Ln = La, Ce, Pr, Nd)
2007
The hydrogenation of propionitrile over binary copper−lanthanide intermetallic compounds (LnCu2, Ln = La, Ce, Pr, Nd) was studied in the gas phase. The results show that the reaction main product is the primary amine, the n-propylamine. To our knowledge, it is the first time that such behavior is reported for copper catalysts.
Intrinsic spin-orbit interaction in diffusive normal wire Josephson weak links: Supercurrent and density of states
2015
We study the effect of the intrinsic (Rashba or Dresselhaus) spin-orbit interaction in superconductor--nanowire--superconductor (SNS) weak links in the presence of a spin-splitting field that can result either from an intrinsic exchange field or the Zeeman effect of an applied field. We solve the full non-linear Usadel equations numerically and analyze the resulting supercurrent through the weak link and the behavior of the density of states in the center of the wire. We point out how the presence of the spin-orbit interaction gives rise to a long-range spin triplet supercurrent, which remains finite even in the limit of very large exchange fields. In particular, we show how rotating the fi…
Pressure-Induced Deformation of Pillar-Type Profiled Membranes and Its Effects on Flow and Mass Transfer
2019
In electro-membrane processes, a pressure difference may arise between solutions flowing in alternate channels. This transmembrane pressure (TMP) causes a deformation of the membranes and of the fluid compartments. This, in turn, affects pressure losses and mass transfer rates with respect to undeformed conditions and may result in uneven flow rate and mass flux distributions. These phenomena were analyzed here for round pillar-type profiled membranes by integrated mechanical and fluid dynamics simulations. The analysis involved three steps: (1) A conservatively large value of TMP was imposed, and mechanical simulations were performed to identify the geometry with the minimum pillar density…