Crystals and crystallinity in polymeric materials

A new view of the concepts of crystallinity and crystals in synthetic macromolecules is discussed. In polymeric materials, crystallinity may be present with the concomitant occurrence of large amounts of structural disorder and in the absence of true three-dimensional long-range order. The structures of semicrystalline polymeric materials are discussed in terms of idealized limit models of crystals, where long-range order may be achieved for structural features that are not necessarily coincident with single atoms and are not necessarily point-centered. Typical examples of non-point-centered structural features are the straight lines corresponding to the chain axes of polymer molecules. This view explains the unusual ability of polymers to crystallize even in the presence of a high degree of structural disorder.     

Lithographically directed assembly of one-dimensional DNA nanostructures via bivalent binding interactions

In order to exploit the outstanding physical properties of one-dimensional (1D) nanostructures such as carbon nanotubes and semiconducting nanowires and nanorods in future technological applications, it will be necessary to organize them on surfaces with precise control over both position and orientation. Here, we use a 1D rigid DNA motif as a model for studying directed assembly at the molecular scale to lithographically patterned nanodot anchors. By matching the inter-nanodot spacing to the length of the DNA nanostructure, we are able to achieve nearly 100% placement yield. By varying the length of single-stranded DNA linkers bound covalently to the nanodots, we are able to study the binding selectivity as a function of the strength of the binding interactions. We analyze the binding in terms of a thermodynamic model which provides insight into the bivalent nature of the binding, a scheme that has general applicability for the controlled assembly of a broad range of functional nanostructures.      

Editorial to theme section on open environmental software systems modeling

Software and Systems Modeling - This theme section aims to disseminate the latest research results in the area of open environmental software systems modeling. Software-intensive systems, such as...     

Voluntary agreements in the field of energy efficiency and emission reduction: Review and analysis of experiences in the European Union

A number of Member States of the EU have introduced voluntary agreements (VAs) that aim to deliver energy savings and emission reductions via increased energy efficiency in different end-use sectors, mainly targeting industry.     

First synthesis of a palladium(0)-containing multimetallic system based on hemilabile pyridylthioether ligands

The complexation of a multidentate ligand based on 2,6-bis(ethylthiomethyl)pyridine units with Pd₂(DBA)₃CHCl₃ in the presence of activated olefins afforded a new tripalladium(0) system.     

Production of lipid microparticles containing bioactive molecules functionalized with PEG

The functionalization of bioactive principles is a relevant issue as it allows increasing their stability, to raise the hydrophilic properties of hydrophobic materials, to reduce the absorption from macrophages and the proteolytic degradation. For this reason, we have functionalized a model protein (Ribonuclease A) with polyethylene glycol (PEG₅₀₀₀).We have investigated the production of lipid/PEG particles incorporating this active principle by a supercritical fluid technology (particles from gas saturated solution, PGSS) to obtain solid micro- and nanoparticles.Runs were carried out to study the process conditions; thus, the effects of the operative variables, such as temperature, pressure and organic solvent, were optimized to obtain micrometric particles.The particles produced were characterized by static light scattering (SLS) to determine their mean and distribution size. The better operative conditions were employed to produce microparticles incorporating Ribonuclease A (RNAse) as both native and PEGylated form.The BCA test was applied to determine the maximum amount of protein incorporated in the particles and the in vitro release. The retained enzymatic activity of proteins after the PEGylation and after the micronization process was also determined by spectrophotometric evaluation.     

Novel Electrocardiographic Patterns for the Prediction of Hypertensive Disorders of Pregnancy—From Pathophysiology to Practical Implications

Hypertensive disorders of pregnancy are a major cause of poor outcome, including placental abruption, organ failure, cerebrovascular accident and disseminated intravascular coagulation. These disorders are associated with increased fetal risk of intrauterine growth restriction, intrauterine death and prematurity. Electrocardiography (ECG) recently emerged as a useful tool to evaluate cardiovascular complications during pregnancy. Specifically, left atrial abnormalities detected by standard ECG are associated with a fourfold increased risk of developing hypertensive disorders during pregnancy. The mechanisms linking left atrial abnormality on ECG with hypertensive disorders are still elusive. Several mechanisms, possibly reflected by abnormal left atrial activation on ECG, has been suggested. These include increased reactivity to angiotensin II and up-regulation of angiotensin type 1 receptors, with activation of autoantibodies targeting these receptors.