Structural organization and dynamics of FCHo2 docking on membranes.

Clathrin-mediated endocytosis (CME) is a central trafficking pathway in eukaryotic cells regulated by phosphoinositides. The plasma membrane phosphatidylinositol-4,5-bisphosphate (PI(4,5)P) plays an instrumental role in driving CME initiation. The F-BAR domain-only protein 1 and 2 complex (FCHo1/2) is among the early proteins that reach the plasma membrane, but the exact mechanisms triggering its recruitment remain elusive.

Metal-Induced Crystallization in Metal Oxides.

ConspectusThe properties of a material depend upon its physical characteristics, one of these being its crystalline state. Next generation solid-state technologies will integrate crystalline oxides into thermal sensitive processes and composite materials. Crystallization of amorphous phases of metal oxides in the solid state typically requires substantial energy input to induce the amorphous to crystalline phase transformation.

Crystal engineering and ferroelectricity at the nanoscale in epitaxial 1D manganese oxide on silicon.

Ferroelectric oxides have attracted much attention due to their wide range of applications, particularly in electronic devices such as nonvolatile memories and tunnel junctions. As a result, the monolithic integration of these materials into silicon technology and their nanostructuration to develop alternative cost-effective processes are among the central points in the current technology. In this work, we used a chemical route to obtain nanowire thin films of a novel Sr1+δMn8O16 (SMO) hollandite-type manganese oxide on silicon.

Epitaxial Nanostructured α-Quartz Films on Silicon: From the Material to New Devices.

In this work, we show a detailed engineering route of the first piezoelectric nanostructured epitaxial quartz-based microcantilever. We will explain all the steps in the process starting from the material to the device fabrication. The epitaxial growth of α-quartz film on SOI (100) substrate starts with the preparation of a strontium doped silica sol-gel and continues with the deposition of this gel into the SOI substrate in a thin film form using the dip-coating technique under atmospheric conditions at room temperature.

Micro/Nanostructure Engineering of Epitaxial Piezoelectric α-Quartz Thin Films on Silicon.

The monolithic integration of sub-micron quartz structures on silicon substrates is a key issue for the future development of piezoelectric devices as prospective sensors with applications based on the operation in the high-frequency range. However, to date, it has not been possible to make existing quartz manufacturing methods compatible with integration on silicon and structuration by top-down lithographic techniques. Here, we report an unprecedented large-scale fabrication of ordered arrays of piezoelectric epitaxial quartz nanostructures on silicon substrates by the combination of soft-chemistry and three lithographic techniques: (i) laser interference lithography, (ii) soft nanoimprint lithography on Sr-doped SiO sol-gel thin films, and (iii) self-assembled SrCO nanoparticle reactive nanomasks.

Tailoring the crystal growth of quartz on silicon for patterning epitaxial piezoelectric films.

Epitaxial films of piezoelectric α-quartz could enable the fabrication of sensors with unprecedented sensitivity for prospective applications in electronics, biology and medicine. However, the prerequisites are harnessing the crystallization of epitaxial α-quartz and tailoring suitable film microstructures for nanostructuration. Here, we bring new insights into the crystallization of epitaxial α-quartz films on silicon (100) from the devitrification of porous silica and the control of the film microstructures: we show that by increasing the quantity of devitrifying agent (Sr) it is possible to switch from an α-quartz microstructure consisting of a porous flat film to one dominated by larger, fully dense α-quartz crystals.

Direct and converse piezoelectric responses at the nanoscale from epitaxial BiFeO thin films grown by polymer assisted deposition.

We use an original water-based chemical method to grow pure epitaxial BiFeO3 (BFO) ultra-thin films with excellent piezoelectric properties. Particularly, we show that this novel chemical route produces higher natural ferroelectric domain size distribution and coercive field compared to similar BFO films grown by physical methods. Moreover, we measured the d33 piezoelectric coefficient of 60 nm thick BFO films by a direct approach, using Direct Piezoelectric Force Microscopy (DPFM).

Electric and Mechanical Switching of Ferroelectric and Resistive States in Semiconducting BaTiO Films on Silicon.

Materials that can couple electrical and mechanical properties constitute a key element of smart actuators, energy harvesters, or many sensing devices. Within this class, functional oxides display specific mesoscale responses which often result in great sensitivity to small external stimuli. Here, a novel combination of molecular beam epitaxy and a water-based chemical-solution method is used for the design of mechanically controlled multilevel device integrated on silicon.

Thermoelectric La-doped SrTiO epitaxial layers with single-crystal quality: from nano to micrometers.

High-quality thermoelectric LaSrTiO (LSTO) films, with thicknesses ranging from 20 nm to 0.7 μm, have been epitaxially grown on SrTiO(001) substrates by enhanced solid-source oxide molecular-beam epitaxy. All films are atomically flat (with rms roughness < 0.

Preparation of Macroporous Epitaxial Quartz Films on Silicon by Chemical Solution Deposition.

This work describes the detailed protocol for preparing piezoelectric macroporous epitaxial quartz films on silicon(100) substrates. This is a three-step process based on the preparation of a sol in a one-pot synthesis which is followed by the deposition of a gel film on Si(100) substrates by evaporation induced self-assembly using the dip-coating technique and ends with a thermal treatment of the material to induce the gel crystallization and the growth of the quartz film. The formation of a silica gel is based on the reaction of a tetraethyl orthosilicate and water, catalyzed by HCl, in ethanol.

Chiral habit selection on nanostructured epitaxial quartz films.

Understanding the crystallization of enantiomorphically pure systems can be relevant to diverse fields such as the study of the origins of life or the purification of racemates. Here we report on polycrystalline epitaxial thin films of quartz on Si substrates displaying two distinct types of chiral habits that never coexist in the same film. We combine Atomic Force Microscopy (AFM) analysis and computer-assisted crystallographic calculations to make a detailed study of these habits of quartz.

Crystallization of hollow mesoporous silica nanoparticles.

Complex 3D macrostructured nanoparticles are transformed from amorphous silica into pure polycrystalline α-quartz using catalytic quantities of alkaline earth metals as devitrifying agent. Walls as thin as 10 nm could be crystallized without losing the architecture of the particles. The roles of cation size and the mol% of the incorporated devitrifying agent in crystallization behavior are studied, with Mg(2+), Ca(2+), Sr(2+) and Ba(2+) all producing pure α-quartz under certain conditions.

Mesoscopically structured nanocrystalline metal oxide thin films.

This review describes the main successful strategies that are used to grow mesostructured nanocrystalline metal oxide and SiO₂ films via deposition of sol-gel derived solutions. In addition to the typical physicochemical forces to be considered during crystallization, mesoporous thin films are also affected by the substrate-film relationship and the mesostructure. The substrate can influence the crystallization temperature and the obtained crystallographic orientation due to the interfacial energies and the lattice mismatch.

Electronic and magnetic structure of LaSr-2×4 manganese oxide molecular sieve nanowires.

In this study we combine scanning transmission electron microscopy, electron energy loss spectroscopy and electron magnetic circular dichroism to get new insights into the electronic and magnetic structure of LaSr-2×4 manganese oxide molecular sieve nanowires integrated on a silicon substrate. These nanowires exhibit ferromagnetism with strongly enhanced Curie temperature (T c >500 K), and we show that the new crystallographic structure of these LaSr-2×4 nanowires involves spin orbital coupling and a mixed-valence Mn3+/Mn4+, which is a must for ferromagnetic ordering to appear, in line with the standard double exchange explanation.

Distance dependence of the photocatalytic efficiency of TiO2 revealed by in situ ellipsometry.

Spectroscopic ellipsometry was utilized to follow in situ photodegradation of organic species in the vicinity of TiO(2) nanoparticles during UV irradiation. Stacked layers composed of TiO(2), mesoporous SiO(2), and mixed mesoporous SiO(2)/TiO(2) nanocomposites with controlled thickness and porosity were used as model materials. Lauric acid molecules and poly(vinyl chloride) (PVC) layers were used as model mobile and immobile pollutants, respectively.

Chemical synthesis of oriented ferromagnetic LaSr-2 × 4 manganese oxide molecular sieve nanowires.

We report a chemical solution based method using nanoporous track-etched polymer templates for producing long and oriented LaSr-2 × 4 manganese oxide molecular sieve nanowires. Scanning transmission electron microscopy and electron energy loss spectroscopy analyses show that the nanowires are ferromagnetic at room temperature, single crystalline, epitaxially grown and self-aligned.

Single crystalline La0.7Sr0.3MnO3 molecular sieve nanowires with high temperature ferromagnetism.

Porous mixed-valent manganese oxides are a group of multifunctional materials that can be used as molecular sieves, catalysts, battery materials, and gas sensors. However, material properties and thus activity can vary significantly with different synthesis methods or process conditions, such as temperature and time. Here, we report on a new synthesis route for MnO(2) and LaSr-doped molecular sieve single crystalline nanowires based on a solution chemistry methodology combined with the use of nanoporous polymer templates supported on top of single crystalline substrates.

Preferential insertion of lactose permease in phospholipid domains: AFM observations.

We report the insertion of a transmembrane protein, lactose permease (LacY) from Escherichia coli (E. coli), in supported lipid bilayers (SLBs) of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG), in biomimetic molar proportions. We provide evidence of the preferential insertion of LacY in the fluid domains.

Synchrotron and neutron diffraction study of 4-methylpyridine-N-oxide at low temperature.

The structure of 4-methylpyridine-N-oxide has been determined at 250, 100 and 10 K by combined synchrotron (C(6)H(7)NO) and neutron (C(6)D(7)NO) powder diffraction experiments. At 250 K the space group is I4(1)/amd and the tetragonal unit cell [a = b = 7.941 (2), c = 19.