Juan Luis López

π-Extended TTF: a versatile molecule for organic electronics

In this review article, we present the features and properties of 9,10-di(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene (exTTF) in molecular electronics. Due to its strong donor character accompanied by a geometrical conformational change upon the formation of the oxidized di-cation species, exTTF has found remarkable applications in several fields of interest including covalent and supramolecular ensembles, molecular wires, artificial photosynthetic systems as well as photovoltaic devices. Furthermore, very recent results have shown an interesting self-organization of hierarchical electroactive nanostructures where exTTF plays a leading role.

Enantioselective Cycloaddition of Münchnones onto [60]Fullerene: Organocatalysis versus Metal Catalysis

Novel chiral catalytic systems based on both organic compounds and metal salts have been developed for the enantioselective [3 + 2] cycloaddition of münchnones onto fullerenes and olefins. These two different approaches proved to be efficient and complementary in the synthesis of optically active pyrrolino[3,4:1,2][60]fullerenes with high levels of enantiomeric excess and moderate to good conversions. Further functionalization of the pyrrolinofullerene carboxylic acid derivatives has been carried out by esterification and amidation reactions.

Highly ordered n/p-co-assembled materials with remarkable charge mobilities.

Controlling self-organization and morphology of chemical architectures is an essential challenge in the search for higher energy-conversion efficiencies in a variety of optoelectronic devices. Here, we report a highly ordered donor/acceptor functional material, which has been obtained using the principle of ionic self-assembly. Initially, an electron donor π-extended tetrathiafulvalene and an electron-acceptor perylene-bisimide were self-organized separately obtaining n- and p-nanofibers at the same scale. These complementary n- and p-nanofibers are endowed with ionic groups with opposite charges on their surfaces. The synergic interactions establish periodic alignments between both nanofibers resulting in a material with alternately segregated donor/acceptor nanodomains. Photoconductivity measurements show values for these n/p-co-assembled materials up to 0.8 cm(2) V(-1) s(-1), confirming the effectiveness in the design of these heterojunction structures. This easy methodology offers great possibilities to achieve highly ordered n/p-materials for potential applications in different areas such as optoelectonics and photovoltaics.

Self‐Ordering Electron Donor–Acceptor Nanohybrids Based on Single‐Walled Carbon Nanotubes Across Different Scales

When dealing with SWCNTs, limited control over theirgrowth and homogeneous production imposes, however,major drawbacks for emerging areas of nanotechnology.Equally problematic is their rather poor solubility in commonorganic solvents. Large spaghetti-like bundles, that originatefrom attractive interactions such as p–p stacking and Londondispersion forces, are the cause of insolubility.

Controlling the crystalline three-dimensional order in bulk materials by single-wall carbon nanotubes

The construction of ordered single-wall carbon nanotube soft-materials at the nanoscale is currently an important challenge in science. Here we use single-wall carbon nanotubes as a tool to gain control over the crystalline ordering of three-dimensional bulk materials composed of suitably functionalized molecular building blocks. We prepare p-type nanofibres from tripeptide and pentapeptide-containing small molecules, which are covalently connected to both carboxylic and electron-donating 9,10-di(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene termini. Adding small amounts of single-wall carbon nanotubes to the so-prepared p-nanofibres together with the externally controlled self assembly by charge screening by means of Ca(2+) results in new and stable single-wall carbon nanotube-based supramolecular gels featuring remarkably long-range internal order.

Controlled Self-Assembly of Electron Donor Nanotubes

We employ a combination of urea-urea hydrogen bonds and pi-pi stacking interactions to obtain soluble self-assembled nanotubes decorated with electron-donor TTF derivatives on the periphery. We have investigated the structure and stability of the nanotubes with a combination of experiments and high-level DFT calculations. We also demonstrate that the association process can be controlled by changes in the hydrogen-bonding ability of the solvent and electrochemically.

Concave versus Planar Geometries for the Hierarchical Organization of Mesoscopic 3D Helical Fibers

Chromophore-peptide systems: a study on a series of pentapeptides covalently connected to planar π systems (1 a and 1 b) or to a curved π system (1 c) showed the influence of the concave shape on the efficient chiral transmission at nano- and mesoscales. Control over the hierarchical growth by H bonding, π-π, and solvophobic interactions made possible the efficient generation of electroactive 3D helical fibers.

Supramolecular One-Dimensional n/p-Nanofibers.

Currently, there is a broad interest in the control over creating ordered electroactive nanostructures, in which electron donors and acceptors are organized at similar length scales. In this article, a simple and efficient procedure is reported en-route towards the construction of 1D arrays of crystalline pristine C60 and phenyl-C61-butyric acid methyl ester (PCBM) coated onto supramolecular fibers based on exTTF-pentapeptides. The resulting n/p-nanohybrids have been fully characterized by a variety of spectroscopic (FTIR, UV-Vis, circular dichroism, Raman and transient absorption), microscopic (AFM, TEM, and SEM), and powder diffraction (X-ray) techniques. Our experimental findings document the tendency of electroactive exTTF-fibers to induce the crystallization of C60 and PCBM, on one hand, and to afford 1D n/p-nanohybrids, on the other hand. Furthermore, photogenerated radical ion pairs, formed upon visible light irradiation of the n/p-nanohybrids, feature lifetimes on the range of 0.9–1.2 ns.

Investigación cualitativa versus cuantitativa: ¿dicotomía metodológica o ideológica?

Critical revision of the historical antagonism between qualitative vs. quantitative research in Health Sciences. We analyze the differences and inferences between both methodologies, concluding that quantitative/qualitative methods, as the ETIC/EMIC perspectives, the signs and symptoms, are orthogonal dimensions required to understand, so decipher reality as offering facts and meanings. However, in her process of scientific construction, the nursing has chosen to oppose the differential qualitative fundamentalism versus biomedical quantitative orthodoxy. And although it is logical, it is still disturbing and counterproductive. After all, doctors and nurses

COSMOS Study Microbiological Results: Bacterial Colonization and Infection of Long-Term Peripheral Catheters

Background: Peripheral venous catheters (PVC) have a lower risk of the infection than central venous catheters (CVC), however, their high frequency of use makes PVC a major problem. Nowadays, there is no consensus regarding the diagnosis of PVC infections and current recommendations are not only utopian but can lead to an underestimation of infection rates. Objectives: To compare the incidence of bacterial colonization and CRI. To identify the significant bacterial colonization in CRI, as well as the main pathogens causing bacterial colonization and CRI in long-term PVC. Material and methods: Nurse-driven, randomized controlled trial to compare closed system (COS) versus open system (MOS), where catheters were removal only by clinical-indication and were inserted and maintained in accordance with CDC guidelines, except those that apply to routine replacement recommendations. The blinded Maki’s semiquantitative culture technique was used. ClinicalTrials.gov (NCT00665886). Results: A total of 1183 catheters (631 patients) were randomized, 584 in the COS group (54,173 catheter-hours recorded), and 599 in the MOS group (50,296). 283 PVC were cultured, i.e. 24% of the sample. The mean in-dwell time to onset of event of COS was 239.5 hours compared to 171.9 with MOS. No significant difference in cumulative incidence or incidence density rates per 1000 catheter-days for bacterial colonization, and no statistical significance were found between rates of CRI (COS, 2.2%; MOS, 2.5%). However, we observed a 22% relative risk reduction (RRR) in CRI with COS. Of the 283 cultures, 21.9% were positive, of which the 46.8% were in COS and 53.2% in MOS. There were no significant differences between microorganisms isolated, number of colonies or type of germ. Staphylococcus was responsible for 80.3% of the colonization, and 85.7% of CRI. S. epidermidis was responsible for 48.8% of colonization and 52.4% of CRI. S. aureus was isolated in two cases (9.5%), one in each group. Discussion: As in previous studies, despite a reduction in the incidence of CRI in closed system, the difference did not reach statistical significance. Nine CRI registered in COS were caused by Gram + (100%), while in MOS 9 CRI were recorded by Gram + (75%), 2 by Gram - (16.7%) and one by Candida (8.3%). Our data seems to confirm that bacteria isolated from closed systems are less virulent and/or that these systems may offer protection against CRI. Conclusion: International guidelines for best clinical practice should differentiate CRI from CRBSI in the management of peripheral lines-related infections. No statistical differences exist between rates of CRI. However, there is a RRR of CRI with closed systems. A total of 29% of the catheter cultured were associated with CRI (26.5% in COS, 31.3% in MOS), suggesting less virulence of the bacteria isolated in closed systems or greater protection offered by such systems. In long-term PVC, staphylococci causes 80% of colonizations, and 100% of CRI in closed systems and while only 75% in open. There were no significant differences between isolated bacteria, the number of colonies or the type of pathogen.