Comparison of freezing tolerance, compatible solutes and polyamines in geographically diverse collections of Thellungiella sp. and Arabidopsis thaliana accessions.

Background: Thellungiella has been proposed as an extremophile alternative to Arabidopsis to investigate environmental stress tolerance. However, Arabidopsis accessions show large natural variation in their freezing tolerance and here the tolerance ranges of collections of accessions in the two species were compared.

Results: Leaf freezing tolerance of 16 Thellungiella accessions was assessed with an electrolyte leakage assay before and after 14 days of cold acclimation at 4°C.

Organic nonvolatile memory devices based on ferroelectricity.

A memory functionality is a prerequisite for many applications of electronic devices. Organic nonvolatile memory devices based on ferroelectricity are a promising approach toward the development of a low-cost memory technology. In this Review Article we discuss the latest developments in this area with a focus on three of the most important device concepts: ferroelectric capacitors, field-effect transistors, and diodes.

Upscaling, integration and electrical characterization of molecular junctions.

The ultimate target of molecular electronics is to combine different types of functional molecules into integrated circuits, preferably through an autonomous self-assembly process. Charge transport through self-assembled monolayers has been investigated previously, but problems remain with reliability, stability and yield, preventing further progress in the integration of discrete molecular junctions. Here we present a technology to simultaneously fabricate over 20,000 molecular junctions-each consisting of a gold bottom electrode, a self-assembled alkanethiol monolayer, a conducting polymer layer and a gold top electrode-on a single 150-mm wafer.

Stabilizing single atom contacts by molecular bridge formation.

Gold-molecule-gold junctions can be formed by carefully breaking a gold wire in a solution containing dithiolated molecules. Surprisingly, there is little understanding on the mechanical details of the bridge formation process and specifically on the role that the dithiol molecules play themselves. We propose that alkanedithiol molecules have already formed bridges between the gold electrodes before the atomic gold-gold junction is broken.

Manipulating the Local Light Emission in Organic Light-Emitting Diodes by using Patterned Self-Assembled Monolayers.

Patterned organic light-emitting diodes are fabricated by using microcontact- printed self-assembled monolayers on a gold anode (see background figure). Molecules with dipole moments in opposite directions result in an increase or a decrease of the local work function (foreground picture), providing a direct handle on charge injection and enabling local modification of the light emission.

Organic non-volatile memories from ferroelectric phase-separated blends.

New non-volatile memories are being investigated to keep up with the organic-electronics road map. Ferroelectric polarization is an attractive physical property as the mechanism for non-volatile switching, because the two polarizations can be used as two binary levels. However, in ferroelectric capacitors the read-out of the polarization charge is destructive.

Self-assembled-monolayer formation of long alkanedithiols in molecular junctions.

The orientation of alkanedithiol molecules in self-assembled monolayers (SAMs) is of vital importance for their transport properties in molecular junctions. It is demonstrated that a too-low concentration of long alkanedithiols in ethanol leads to the formation of looped molecules, resulting in a 50-fold increase of the current through the SAM. X-ray photoelectron spectroscopy measurements show that high-concentration dithiol solutions result in a preferential standing-up phase.

Electron tunneling through alkanedithiol self-assembled monolayers in large-area molecular junctions.

The electrical transport through self-assembled monolayers of alkanedithiols was studied in large-area molecular junctions and described by the Simmons model [Simmons JG (1963) J Appl Phys 34:1793-1803 and 2581-2590] for tunneling through a practical barrier, i.e., a rectangular barrier with the image potential included.

Towards molecular electronics with large-area molecular junctions.

Electronic transport through single molecules has been studied extensively by academic and industrial research groups. Discrete tunnel junctions, or molecular diodes, have been reported using scanning probes, break junctions, metallic crossbars and nanopores. For technological applications, molecular tunnel junctions must be reliable, stable and reproducible.

Metallic contact formation for molecular electronics: interactions between vapor-deposited metals and self-assembled monolayers of conjugated mono- and dithiols.

We present grazing-incidence Fourier transform infrared and AFM data of Au, Al, and Ti vapor-deposited onto self-assembled monolayers (SAMs) of conjugated mono- and dithiols. SAMs of 4,4'''-dimercapto-p-quaterphenyl, 4,4"-dimercapto-p-terphenyl, and 4,4'-dimercapto-p-biphenyl have reactive thiols at the SAM/vacuum interface that interact with vapor-deposited Au or Al atoms, preventing metal penetration. Conjugated monothiols lack such metal blocking groups, and metals (Au, Al) can penetrate into their SAMs.

Cytokeratin 17 and p63 are markers of the HPV target cell, the cervical stem cell.

Background: Basic research on HPV has focused on identifying the genetic changes that lead to cervical carcinoma. However, while focusing on the molecular biology of the cancer, understanding of its cellular biology has lagged: the target cell of the HPV infection is unknown.

Materials And Methods: In this study we identified the stem cell population of the cervical epithelium by monoclonal antibodies against p63, a homologue of the tumor suppressor gene p53 and cytokeratin 17 (CK17).

Pharmacological investigations on lipopolysaccharide-induced permeability changes in the blood-brain barrier in vitro.

Lipopolysaccharide-induced changes in blood-brain barrier (BBB) permeability were investigated with a pharmacological approach in vitro. Lipopolysaccharide induced a concentration- and time-dependent (non)reversible opening of the BBB, and brain astrocytes make brain capillary endothelial cells (BCEC) resistant to this BBB disruption. De novo protein synthesis was essential for the recovery, because cycloheximide prevented the recovery process.

Synthesis of a Conjugated Macromolecular Initiator for Nitroxide-Mediated Free Radical Polymerization.

Controlled synthesis of rod-coil block copolymers is possible with a new macroinitiator for "living" nitroxide-mediated radical polymerization (NMRP). The synthesis of the new macroinitiator which contains a rodlike, conjugated poly(p-phenylene vinylene) block is described. Electron microscopy imaging indicates microphase separation of the resulting block copolymer when cast from chloroform.