341 research outputs found
Thermal stability and long term hydrogen/deuterium release from soft to hard amorphous carbon layers analyzed using in-situ Raman spectroscopy. Comparison with Tore Supra deposits
The thermal stability of 200 nm thick plasma enhanced chemical vapor
deposited a-C:H and a-C:D layers ranging from soft to hard layers has been
studied and compared to that of deposits collected on the Tore Supra tokamak
plasma facing components by means of in-situ Raman spectroscopy. Linear ramp
heating and long term isotherms (from several minutes to 21 days) have been
performed and correlations between spectrometric parameters have been found.
The information obtained on the sp 2 clustering has been investigated by
comparing the G band shift and the 514 nm photon absorption evolution due to
the thermal treatment of the layer. The effects of isotopic substitution have
also been investigated.Comment: appears in Thin Solid Films, Elsevier, 201
Efficient microwave-assisted synthetic protocols and in silico behaviour prediction of per-substituted β-cyclodextrins
Existence of solutions for a higher order non-local equation appearing in crack dynamics
In this paper, we prove the existence of non-negative solutions for a
non-local higher order degenerate parabolic equation arising in the modeling of
hydraulic fractures. The equation is similar to the well-known thin film
equation, but the Laplace operator is replaced by a Dirichlet-to-Neumann
operator, corresponding to the square root of the Laplace operator on a bounded
domain with Neumann boundary conditions (which can also be defined using the
periodic Hilbert transform). In our study, we have to deal with the usual
difficulty associated to higher order equations (e.g. lack of maximum
principle). However, there are important differences with, for instance, the
thin film equation: First, our equation is nonlocal; Also the natural energy
estimate is not as good as in the case of the thin film equation, and does not
yields, for instance, boundedness and continuity of the solutions (our case is
critical in dimension in that respect)
Constituting a public umbilical cord blood bank in South Africa
No abstract availableThe
South African Medical Research Council of in terms of the MRC’s Flagships Awards
Project SAMRC-RFA-UFSP-01-2013/STEM CELLS, the Institute for Cellular and
Molecular Medicine of the University of Pretoria, and the National Research
Foundation of South Africa.http://www.nature.com/bmt2015-09-30hb201
Heterogeneity of cell therapy products
Cellular therapy has become a billion-dollar industry and is set to become one of the therapeutic pillars of healthcare in the 21st century. Adult stem cells, which include haematopoietic stem and progenitor cells (HSPCs) and mesenchymal stromal/stem cells (MSCs), is one of the major cell types currently under investigation for use in cell therapy. This review focuses on HSPCs and MSCs and discusses their heterogeneous nature and the problems faced in expanding these cells to therapeutic numbers for use in clinical applications
Thermal conductivity in harmonic lattices with random collisions
We review recent rigorous mathematical results about the macroscopic
behaviour of harmonic chains with the dynamics perturbed by a random exchange
of velocities between nearest neighbor particles. The random exchange models
the effects of nonlinearities of anharmonic chains and the resulting dynamics
have similar macroscopic behaviour. In particular there is a superdiffusion of
energy for unpinned acoustic chains. The corresponding evolution of the
temperature profile is governed by a fractional heat equation. In non-acoustic
chains we have normal diffusivity, even if momentum is conserved.Comment: Review paper, to appear in the Springer Lecture Notes in Physics
volume "Thermal transport in low dimensions: from statistical physics to
nanoscale heat transfer" (S. Lepri ed.
Relative entropy and the stability of shocks and contact discontinuities for systems of conservation laws with non BV perturbations
We develop a theory based on relative entropy to show the uniqueness and L^2
stability (up to a translation) of extremal entropic Rankine-Hugoniot
discontinuities for systems of conservation laws (typically 1-shocks, n-shocks,
1-contact discontinuities and n-contact discontinuities of large amplitude)
among bounded entropic weak solutions having an additional trace property. The
existence of a convex entropy is needed. No BV estimate is needed on the weak
solutions considered. The theory holds without smallness condition. The
assumptions are quite general. For instance, strict hyperbolicity is not needed
globally. For fluid mechanics, the theory handles solutions with vacuum.Comment: 29 page
Reversible Light-Induced Dimerization of Secondary Face Azobenzene-Functionalized β-Cyclodextrin Derivatives
β-cyclodextrin (βCyD) derivatives equipped with aromatic appendages at the secondary face exhibit tailorable self-assembling capabilities. The aromatic modules can participate in inclusion phenomena and/or aromatic-aromatic interactions. Supramolecular species can thus form that, at their turn, can engage in further co-assembling with third components in a highly regulated manner; the design of nonviral gene delivery systems is an illustrative example. Endowing such systems with stimuli responsiveness while keeping diastereomeric purity and a low synthetic effort is a highly wanted advancement. Here, we show that an azobenzene moiety can be “clicked” to a single secondary O-2 position of βCyD affording 1,2,3-triazole-linked βCyD-azobenzene derivatives that undergo reversible light-controlled self-organization into dimers where the monomer components face their secondary rims. Their photoswitching and supramolecular properties have been thoroughly characterized by UV-vis absorption, induced circular dichroism, nuclear magnetic resonance, and computational techniques. As model processes, the formation of inclusion complexes between a water-soluble triazolylazobenzene derivative and βCyD as well as the assembly of native βCyD/βCyD-azobenzene derivative heterodimers have been investigated in parallel. The stability of the host-guest supramolecules has been challenged against the competitor guest adamantylamine and the decrease of the medium polarity using methanol-water mixtures. The collective data support that the E-configured βCyD-azobenzene derivatives, in aqueous solution, form dimers stabilized by the interplay of aromatic-aromatic and aromatic-βCyD cavity interactions after partial reciprocal inclusion. Photoswitching to the Z-isomer disrupts the dimers into monomeric species, offering opportunity for the spatiotemporal control of the organizational status by light.Ministerio de Ciencia e InnovaciĂłn PID2019-105858RB-I00, PID2020-118403GB-I00, PID2020-118384GB-I00, PID2020-119130GB-I00Fondo Europeo de Desarrollo Regional PID2021-124247OB-C21Junta de AndalucĂa P20_00166, US-1380698, P12-FQM-1467Universidad de Sevilla FPU18/02922, FPU19/0436
Trehalose-based siamese twin amphiphiles with tunable self-assembling, DNA nanocomplexing and gene delivery properties
An original family of multivalent vectors encompassing gemini and facial amphiphilicity, namely cationic Siamese twin surfactants, has been prepared fromthe disaccharide trehalose; molecular engineering lets us modulate the self-assembling properties and the topology of the nanocomplexes with plasmid DNA for efficient gene delivery in vitro and in vivo
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