Out-Of-Plane Metal Coordination for a True Solvent-Free Building with Molecular Bricks: Dodging the Surface Ligand Effect for On-Surface Vacuum Self-Assembly

The desirable self-assembly (SA) of repeated 2D stacked layers requires a “holistic analysis” of three interconnected components: the electrode, the interface, and the molecular component; among them, the contact interface bears the largest burden responsibilities. Epitaxial growth (EG) of coherent 2D+n stacked heterojunction by solvent-free deposition holds great promise, although the feasibility has never been demonstrated given multiple drawbacks (e.g., surface-ligand effect, SLE). Here, it is demonstrated how a coherent 2D+n (n = 3) layered heterorganic film is grown on an archetypal Fe metal electrode. The groundbreaking achievement is the result of the in-vacuum integration of: i) chemical decoupling of the basal organic layer (a Zn^II-tetraphenylporphyrine, ZnTPP) from the metal electrode, ii) 2D-ordering of the ZnTPP commensurate to the substrate, iii) rigid, stoichiometric, and orthogonally arranged, the molecule-to-molecule coupling between ZnTPP and a ditopic linear bridging ligand (i.e., DPNDI) guided by SA coordination chemistry, and iv) sharp (chemical) termination of the layered film.     

Effects of calcium nitride and calcium carbonate gasifying agents on the combustion synthesis of Ni3Ti-TiC composites

The synthesis of nickel-titanium (NiTi) intermetallic composites is of considerable interest due to the ability to create a porous material with high strength and improved wear resistance. The effects of adding a carbon reactant to modify the reaction products and exothermicity have been studied using two reaction stoichiometries involving elemental nickel, titanium and carbon (graphite). The present study examines the synthesis of porous Ni₃Ti intermetallic composites in the presence of calcium nitride or calcium carbonate gasifying agent. Both gasifying agents show significant effects on the ignition characteristics of the reaction, burning velocities and TiC particle sizes present in the final product, but do not affect the combustion temperatures.     

Gain and ultrafast optical switching in PMMA optical fibers and films doped with luminescent conjugated polymers and oligomers

Conjugated luminescent polymers and oligomers, exhibiting stimulated emission (SE), are dispersed in polymethylmethacrylate (PMMA), films and optical fibers, either by blending or upon copolymerisation. With this PMMA doping, we aim to achieve gain and ultrafast optical switching. The modification of the dopant's chemical structure allows the tuning of the SE spectral region. Furthermore, we aim to achieve dopant chain isolation while maximising their concentration. In this paper, we present an overview of the research done in this area in the context of the European Union (EU)-funded research project "plastic optical fibers with embedded active polymers for data communications - POLYCOM".     

Thermal conductivity of Tecamax® SRP from millikelvin temperatures to room temperature

Tecamax® SRP (self-reinforced polyphenylene) is a new commercially available amorphous polymer which is suitable for use at cryogenic temperatures. It has a high tensile strength (210 MPa at room temperature), resulting from the molecular structure of the polymer rather than by the addition of reinforcing materials. We have measured the thermal conductivity between 60 mK and 280 K. We find that the conductivity below 10 K is similar to, but lower than, most amorphous materials, and the material offers a good combination of low conductivity at low temperatures and high tensile strength. Our results suggest that the material may in fact have a small crystalline component, which may be a partial explanation for the low conductivity. Above 10 K, the temperature dependence of the conductivity is different from most amorphous materials. We are unaware of previous measurements of the thermal conductivity of this material, even at room temperature.     

Long-lived charged states in single-walled carbon nanotubes

We present continuous wave photoinduced absorption spectroscopy of single-walled carbon nanotubes dispersed in a polymer matrix. The spectrum is dominated by a modulation of the absorption line shape, predominantly of large diameter tubes, that we assigned to electroabsorption caused by local electric fields arising from trapped photoinduced charges. The lack of selectivity in the excitation points to an efficient migration of the photoexcited states, either the singlet excitons or the charges resulting from their dissociation.     

Broadband Defects Emission and Enhanced Ligand Raman Scattering in 0D Cs3Bi2I9 Colloidal Nanocrystals

Excitonic 0D and 2D lead‐halide perovskites have been recently developed and investigated as new materials for light generation. Here broadband (>1 eV) emission from newly synthesized 0D lead‐free colloidal Cs₃Bi₂I₉ nanocrystals (NCs) is reported. The nature of their emissive states as well as the relative dynamics which are currently hotly debated are investigated. In particular, it is found that the broadband emission is made by the coexistence of emissive excitons and sub‐bandgap emissive trap‐states. Remarkably, evidence of enhanced Raman scattering from the ligands is observed when attached to the NCs surface, an effect that is preliminarily attributed to strong exciton‐ligands electronic coupling in these systems.     

X‐ray Structures and Feasibility Assessment of CLK2 Inhibitors for Phelan–McDermid Syndrome

CLK2 inhibition has been proposed as a potential mechanism to improve autism and neuronal functions in Phelan–McDermid syndrome (PMDS). Herein, the discovery of a very potent indazole CLK inhibitor series and the CLK2 X‐ray structure of the most potent analogue are reported. This new indazole series was identified through a biochemical CLK2 Caliper assay screen with 30k compounds selected by an in silico approach. Novel high‐resolution X‐ray structures of all CLKs, including the first CLK4 X‐ray structure, bound to known CLK2 inhibitor tool compounds (e.g., TG003, CX‐4945), are also shown and yield insight into inhibitor selectivity in the CLK family. The efficacy of the new CLK2 inhibitors from the indazole series was demonstrated in the mouse brain slice assay, and potential safety concerns were investigated. Genotoxicity findings in the human lymphocyte micronucleus test (MNT) assay are shown by using two structurally different CLK inhibitors to reveal a major concern for pan‐CLK inhibition in PMDS.     

A simple,stable, and accurate linear tetrahedral finite element for transient,nearly, and fully incompressible solid dynamics: a dynamic variational multiscale approach

We propose a new approach for the stabilization of linear tetrahedral finite elements in the case of nearly incompressible transient solid dynamics computations. Our method is based on a mixed formulation, in which the momentum equation is complemented by a rate equation for the evolution of the pressure field, approximated with piecewise linear, continuous finite element functions. The pressure equation is stabilized to prevent spurious pressure oscillations in computations. Incidentally, it is also shown that many stabilized methods previously developed for the static case do not generalize easily to transient dynamics. Extensive tests in the context of linear and nonlinear elasticity are used to corroborate the claim that the proposed method is robust, stable, and accurate. Copyright © 2015 John Wiley & Sons, Ltd.     

A Potent and Selective P‐gp Modulator for Altering Multidrug Resistance Due to Pump Overexpression

P‐glycoprotein (P‐gp) is a membrane protein responsible for the active transport of several endogenous and exogenous substances. It constitutes a defense mechanism and, at the same time, it severely compromises the success rate of antitumor chemotherapy. In this study a small library of alkyl/oxyalkyl derivatives of MC70 [4′‐(6,7‐dimethoxy‐3,4‐dihydro‐1H‐isoquinolin‐2‐ylmethyl)biphenyl‐4‐ol], a well‐known P‐gp inhibitor, was synthesized through straightforward functionalization of the phenolic group present in the structure of MC70. All compounds were characterized for their effect on P‐gp, proving capable of blocking P‐gp‐mediated calcein‐AM efflux with micromolar potency, following their ability to act as high‐affinity substrates of this transporter. Excitingly, compound 4 [6,7‐dimethoxy‐2‐((4′‐butoxybiphen‐4‐yl)methyl)‐1,2,3,4‐tetrahydroisoquinoline] exhibited low nanomolar potency (5.2 nm ) and had a peculiar activity profile, acting both as a positive allosteric modulator and as a substrate of the transporter. A new and more efficient synthesis of MC70 is also described.