Vibrational and Anion Photoelectron Spectroscopy of Transition Metal Clusters

The understanding of chemical bonding and of the resulting atomic arrangements is a central topic in molecular physics. The bonding mechanisms of transition metal atoms still constitute a challenge in their theoretical description due to the massive number of valence electrons. Moreover, small transition metal clusters and their complexes may serve as models for catalytic systems of interest for science and technology. The goal of this thesis is the characterization of the geometric and electronic structures of isolated transition metal clusters in the gas phase and, consequently, a better understanding of their bonding nature. The first part of the thesis encompasses experimental results and conclusions for the anionic platinum trimer (Pt3-) and the tantalum nitride anion (TaN-). The data is obtained through anion photoelectron spectroscopy via velocity map imaging (VMI), which permits the simultaneous measurement of photoelectron spectra and photoelectron angular distributions (PADs). The study on TaN- reports the first photoelectron spectra of this diatomic molecule. The spectroscopic assignments, carried out with the support of previous theoretical and experimental works, provide measurements of the adiabatic electron affinity (EAad) and of the vibrational frequencies of the anion and the neutral molecule. In addition, the analysis of the PADs reveals the existence of two core excited shape resonances and disentangles the hybridization of a key molecular orbital. In the study of Pt3-, the experiment is performed in the slow electron velocity map imaging (SEVI) mode to resolve the low-frequency vibrational structure, characteristic of metal clusters. A plethora of information is obtained with the support of density functional theory (DFT) calculations, which includes the presence of two isomeric forms (triangular and linear) and hints at pseudo Jahn-Teller and Jahn-Teller effects. Some of the PADs reveal an oscillatory energetic dependence that, according to the quantum analogy established by Fano with the Young’s double slit experiment, is interpreted as interferometric efects in the linear isomer. In the second part of the thesis, the characterizations of CoArn+ (n=3 to 6), Con-mMnmArx+ (n=3 to 14; m=0 to 2) and saturated cationic Ru cluster carbonyls Run(CO)m+ (n=1 to 8) via (far-)infrared multiple photon dissociation (IRMPD) spectroscopy, more suitable to obtain structural information on the studied complexes, are reported. The investigation on CoArn+ readdresses the question on the nature of the interaction between the metal cation and the rare gas atom by proposing some amount of covalency in the bonding. Motivated by the role of ruthenium as catalyst for CO methanation in the Fischer-Tropsch process, the composition and structures of saturated cationic ruthenium carbonyls are studied. Their IR spectra are obtained in the range of the C-O stretches, Ru-CO stretches and deformation modes. Structural assignment is achieved with the aim of DFT calculations and the results corroborate former predictions. Finally, IR spectra of Con-mMnmArx+ are presented and discussed in comparison to those of pure cobalt clusters with the purpose of motivating future theoretical studies that may solve the puzzling structures of these binary metal clusters.Das Verständnis der chemischen Bindung und der daraus folgenden räumlichen Anordnungen von Atomen ist ein zentrales Thema der Molekülphysik. Die große Zahl der Valenzelektronen von Übergangsmetall-Atomen stellt auch heute noch eine Herausforderung für die theoretische Beschreibung ihrer Bindungsmechanismen dar. Gleichwohl können kleine Übergangsmetallcluster und ihre Komplexe als Modelle für katalytische Systeme von Relevanz in Wissenschaft und Technik dienen. Das Ziel dieser Arbeit ist die Charakterisierung der geometrischen und elektronischen Strukturen von isolierten Übergangsmetallclustern in der Gasphase und damit ein besseres Verständnis für das Wesen ihrer chemischen Bindung. Der erste Teil dieser Arbeit beinhaltet experimentelle Ergebnisse und darauf beruhende Schlussfolgerungen für das Anion des Platintrimers (Pt3-)und das Tantalnitrid-Anion (TaN-). Die Daten basieren auf Anionen-Photoelek- tronenspektroskopie mittels velocity map imaging (VMI), einer Technik, die die gleichzeitige Messung der Photoelektronenspektren und der Winkelverteil- ung der Photoelektronen ermöglicht. Für das zweiatomige Molekül TaN- wurde das Photoelektronenspektrum erstmalig bestimmt. Die spektroskopische Zuordnung gelang unter Zuhilfenahme vorhergehender theoretischer und experimenteller Arbeiten und liefert Werte für die adiabatische Elektronenaffinität (EAad) sowie die Schwingungsfrequenzen des Anions und des neutralen Moleküls. Weiterhin lässt die Untersuchung der Winkelverteilung auf das Vorliegen von zwei rumpfangeregten Formresonanzen (engl. core excited shape resonances) schließen und erlaubt die Analyse der Hybridisierung eines wichtigen Molekülorbitals. Die experimentelle Untersuchung von Pt3- erfolgte im SEVI-Modus (von engl. slow electron velocity map imaging), um die Schwingungsstruktur bei den für Metallclustern charakteristischen niedrigen Frequenzen aufzulösen. Die große Menge an experimentellen Daten erlaubt, unterstützt durch Dichtefunktionaltheorie(DFT)-Rechnungen, den Nachweis von zwei isomeren Formen (linear und gewinkelt) und liefert Hinweise auf den Einfluss von Jahn-Teller- und Pseudo-Jahn-Teller-Effekten. Einige Winkelverteilungen zeigen eine oszillierende Energieabhängigkeit, die, entsprechend der von Fano beschriebenen Quanten-Analogie zu Youngs Doppelspaltexperiment, als Interferenzeffekt im linearen Isomer gedeutet werden kann. Der zweite Teil der Arbeit widmet sich der Charakterisierung von CoArn+ (n=3 to 6), Con-mMnmArx+ (n=3 to 14; m=0 to 2) und gesättigten kationischen Rutheniumcluster-Carbonylen Rum(CO)m+ (n=1 to 8) mittels (Fern-)Infrarot Mehrphotonendissoziations-(IRMPD)-Spektroskopie, welche besonders geeignet ist, Strukturinfomationen für diese Komplexe zu erlangen. Die Untersuchung von CoArn+ widmet sich der Frage nach der Art der Wechselwirkung zwischen Metallkation und Edelgasatom und lässt auf einen kovalenten Anteil an der Bindung schließen. Motiviert durch die Funktion von Ruthenium als Katalysator bei der CO-Methanisierung in der Fischer-Tropsch-Synthese wurden Zusammensetzung und Struktur von gesättigten kationischen Rutheniumcarbonylen untersucht. Deren IR-Spektren wurden im Bereich der C-O Streckschwingung sowie der Ru-CO Streck- und Deformationsmoden bestimmt. Die Zuordnung der Strukturen gelang mit Hilfe von DFT-Rechnungen und bestätigt frühere Vorhersagen. Schließlich werden die IR-Spektren von Con-mMnmArx+ vorgestellt und, im Vergleich zu denen der reinen Cobaltcluster, diskutiert. Diese Daten stehen als Motivation für zukünftige theoretische Untersuchungen, die das Rätsel um die Strukturen dieser binären Metallcluster lösen könnten

Improved wear performance of ultra high molecular weight polyethylene coated with hydrogenated diamond like carbon

Hydrogenated diamond like carbon (DLCH) thin films were deposited on medical grade ultra high molecular weight polyethylene (UHMWPE) by radio frequency plasma enhanced chemical vapor deposition. The DLCH coating thicknesses ranged from 250 to 700. nm. The substrates were disks made of UHMWPEs typically used for soft components in artificial joints, namely virgin GUR 1050 and highly crosslinked (gamma irradiated in air to 100. kGy) UHMWPEs. Mechanical and tribological properties under bovine serum lubrication at body temperature were assessed on coated and uncoated polyethylenes by means of nano-hardness and ball-on-disk tests, respectively. Morphological features of the worn surfaces were obtained by confocal microscopy and scanning electron microscopy. This study confirms an increase in surface hardness and good wear resistance for coated materials after 24. h of sliding test compared to uncoated polyethylene. These results point out that to coat UHMWPE with DLCH films could be a potential method to reduce backside wear in total hip and knee arthroplasties.Ministerio de Ciencia y Educación MAT2006-12603- C02-01, CSD2008-0002

Coenzyme Q10 in the treatment of mitochondrial disease

Currently, there is a paucity of available treatment strategies for oxidative phosphorylation disorders. Coenzyme Q10 (CoQ10) and related synthetic quinones are the only agents to date that have proven to be beneficial in the treatment of these heterogeneous disorders. The therapeutic efficacy of CoQ10 is not restricted to patients with an underlying CoQ10 deficiency and is thought to result from its ability to restore electron flow in the mitochondrial respiratory chain (MRC) as well as to increase the cellular antioxidant capacity. At present, however, there is no consensus on the appropriate dosage or therapeutic plasma level of CoQ10, and this information will be required before CoQ10 can be utilized effectively in the treatment of mitochondrial disease. The following review will outline our current knowledge on the use of CoQ10 in the treatment of MRC disorders and primary CoQ10 deficiencies. Keyword

Using ion beams to tune the nanostructure and optical response of co-deposited Ag : BBBN thin films

The present study is devoted to co-deposited Ag : BN nanocermet thin films and is focused on the influence of ion irradiation conditions on their structural and linear optical properties. Ion irradiation was performed in situ during the growth of the nanocermets using a 50 eV assistance beam (nitrogen/argon or nitrogen-ion assistance) and ex situ on as-grown films using a 120 keV argon-ion beam (post-irradiation). Grazing incidence small-angle x-ray scattering measurements show that (i) as-grown N-assisted films contain prolate spheroidal clusters (height-to-diameter ratio H/D ≈ 1.8), (ii) N/Ar-ion assistance leads to the formation of more elongated clusters (H/D ≈ 2.1) and (iii) post-irradiation leads to a decrease of H/D to a value close to 1. These results are discussed on the basis of atomic diffusion processes involved during the growth of the nanocermets and during the post-irradiation. The optical transmittance spectra of these films measured at normal incidence display one absorption band, due to the excitation of the (1,1) plasmon mode of the clusters. In the case of the as-grown films, an additional band appears at oblique incidence for P-polarized light, as a consequence of the excitation of the (1,0) plasmon mode of the clusters. Our results show that the spectral position of the absorption bands (which can be tuned in the 400-600 nm range) depends on the H/D ratio of the clusters, in good agreement with calculations of optical transmittance considering the nanocomposite layer as a uniaxial anisotropic medium whose dielectric tensor is described by an anisotropic Maxwell-Garnett model. © 2007 IOP Publishing Ltd.The authors would like to thank CNRS-CSIC and Picasso programmes for financial support which permitted the collaboration between the Instituto de Ciencia de Materiales de Sevilla (Spain) and the Laboratoire de Metallurgie Physique ´ de Poitiers (France). The authors also thank J P Simon and the D2AM staff at the ESRF for their support during the GISAXS measurements.Peer Reviewe

The Value of Coenzyme Q10 Determination in Mitochondrial Patients.

Coenzyme Q10 (CoQ) is a lipid that is ubiquitously synthesized in tissues and has a key role in mitochondrial oxidative phosphorylation. Its biochemical determination provides insight into the CoQ status of tissues and may detect CoQ deficiency that can result from either an inherited primary deficiency of CoQ metabolism or may be secondary to different genetic and environmental conditions. Rapid identification of CoQ deficiency can also allow potentially beneficial treatment to be initiated as early as possible. CoQ may be measured in different specimens, including plasma, blood mononuclear cells, platelets, urine, muscle, and cultured skin fibroblasts. Blood and urinary CoQ also have good utility for CoQ treatment monitoring

Correction: Russo, B., et al. Assessment of urban flood resilience in barcelona for current and future scenarios. the resccue project. (Sustainability 2020, 12, 5638)

The authors would like to make the following corrections about the published paper [1]. The changes are as follows: (1) Replacing Table 4. Reference 1. Russo, B.; Velasco, M.; Locatelli, L.; Sunyer, D.; Yubero, D.; Monjo, R.; Martínez-Gomariz, E.; Forero-Ortiz, E.; Sánchez-Muñoz, D.; Evans, B.; et al. Assessment of Urban Flood Resilience in Barcelona for Current and Future Scenarios. The RESCCUE Project. Sustainability 2020, 12, 5638. [CrossRef]

Haemophilus parasuis

The expression of chemokines (CCL-2 and CXCL-8) and cytokines (IL-1α, IL-1β, IL-6, TNF-α, and IL-10) was evaluated by RT-qPCR in colostrum-deprived pigs vaccinated and challenged with Haemophilus parasuis serovar 5. Two vaccines containing native proteins with affinity to porcine transferrin (NPAPTim and NPAPTit) were tested, along with two control groups: one inoculated with PBS instead of antigen (challenge group (CHG)), and another one nonimmunized and noninfected (blank group). The use of NPAPTim and NPAPTit resulted in complete protection against H. parasuis (no clinical signs and/or lesions), and both vaccines were capable of avoiding the expression of the proinflammatory molecules to levels similar to physiological values in blank group. However, overexpression of all proinflammatory molecules was observed in CHG group, mainly in the target infection tissues (brain, lungs, and spleen). High expression of CCL-2, CXCL-8, IL-1α, IL-1β, and IL-6 can be considered one of the characteristics of H. parasuis infection by serovar 5

Effect of surface roughness and sterilization on bacterial adherence to ultra-high molecular weight polyethylene

AbstractSterilization with ethylene oxide (EO) and gas plasma (GP) are well-known methods applied to ultra-high molecular weight polyethylene (UHMWPE) surfaces in the belief that they prevent major material changes caused by gamma irradiation. However, the influence of these surface sterilization methods on bacterial adherence to UHMWPE is unknown. UHMWPE samples with various degrees of roughness (0.3, 0.8 and 2.0 µm) were sterilized with either GP or EO. The variations in hydrophobicity, surface free energy and surface functional groups were investigated before and after sterilization. Sterilized samples were incubated with either Staphylococcus aureus or Staphylococcus epidermidis in order to study bacterial adherence to these materials. Fewer bacteria adhered to UHMWPE after sterilization with EO than after sterilization with GP, especially to the smoothest surfaces. No changes in chemical composition of the UHMWPE surface due to sterilization were observed using X-ray photoemission spectroscopy analysis. The decreased bacterial adherence to UHMWPE found at the smoothest surfaces after sterilization with EO was not directly related to changes in chemical composition. Increased bacterial adherence to rougher surfaces was associated with increased polar surface energy of EO-sterilized surfaces

Haemophilus parasuis Subunit Vaccines Based on Native Proteins with Affinity to Porcine Transferrin Prevent the Expression of Proinflammatory Chemokines and Cytokines in Pigs

8 p.The expression of chemokines (CCL-2 and CXCL-8) and cytokines (IL-1, IL-1, IL-6, TNF-, and IL-10) was evaluated by RTqPCR in colostrum-deprived pigs vaccinated and challenged with Haemophilus parasuis serovar 5. Two vaccines containing native proteins with affinity to porcine transferrin (NPAPTim and NPAPTit) were tested, along with two control groups: one inoculated with PBS instead of antigen (challenge group (CHG)), and another one nonimmunized and noninfected (blank group). The use of NPAPTim and NPAPTit resulted in complete protection against H. parasuis (no clinical signs and/or lesions), and both vaccines were capable of avoiding the expression of the proinflammatory molecules to levels similar to physiological values in blank group. However, overexpression of all proinflammatory molecules was observed in CHG group, mainly in the target infection tissues (brain, lungs, and spleen). High expression of CCL-2, CXCL-8, IL-1, IL-1, and IL-6 can be considered one of the characteristics of H. parasuis infection by serovar 5S

Mechano-Optical Analysis of Single Cells with Transparent Microcapillary Resonators

The study of biophysical properties of single cells is becoming increasingly relevant in cell biology and pathology. The measurement and tracking of magnitudes such as cell stiffness, morphology, and mass or refractive index have brought otherwise inaccessible knowledge about cell physiology, as well as innovative methods for high-throughput label-free cell classification. In this work, we present hollow resonator devices based on suspended glass microcapillaries for the simultaneous measurement of single-cell buoyant mass and reflectivity with a throughput of 300 cells/minute. In the experimental methodology presented here, both magnitudes are extracted from the devices' response to a single probe, a focused laser beam that enables simultaneous readout of changes in resonance frequency and reflected optical power of the devices as cells flow within them. Through its application to MCF-7 human breast adenocarcinoma cells and MCF-10A nontumorigenic cells, we demonstrate that this mechano-optical technique can successfully discriminate pathological from healthy cells of the same tissue type