Local Prefrontal Cortex TMS-Induced Reactivity Is Related to Working Memory and Reasoning in Middle-Aged Adults

Introduction: The prefrontal cortex (PFC) plays a crucial role in cognition, particularly in executive functions. Cortical reactivity measured with Transcranial Magnetic Stimulation combined with Electroencephalography (TMS-EEG) is altered in pathological conditions, and it may also be a marker of cognitive status in middle-aged adults. In this study, we investigated the associations between cognitive measures and TMS evoked EEG reactivity and explored whether the effects of this relationship were related to neurofilament light chain levels (NfL), a marker of neuroaxonal damage. Methods: Fifty two healthy middle-aged adults (41–65 years) from the Barcelona Brain Health Initiative cohort underwent TMS-EEG, a comprehensive neuropsychological assessment, and a blood test for NfL levels. Global and Local Mean-Field Power (GMFP/LMFP), two measures of cortical reactivity, were quantified after left prefrontal cortex (L-PFC) stimulation, and cognition was set as the outcome of the regression analysis. The left inferior parietal lobe (L-IPL) was used as a control stimulation condition. Results: Local reactivity was significantly associated with working memory and reasoning only after L-PFC stimulation. No associations were found between NfL and cognition. These specific associations were independent of the status of neuroaxonal damage indexed by the NfL biomarker and remained after adjusting for age, biological sex, and education. Conclusion: Our results demonstrate that TMS evoked EEG reactivity at the L-PFC, but not the L-IPL, is related to the cognitive status of middle-aged individuals and independent of NfL levels, and may become a valuable biomarker of frontal lobe-associated cognitive function

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Morphologie und Wachstum von Titandioxid-Nanoröhren : Nanostrukturierung und Anwendungen

Self-ordering phenomena during anodic oxidation of metals and the formation of porous oxides have been of a great interest to science and technology for more than 50 years. Particularly, after Masuda et al. demonstrated ideally ordered porous alumina by fine tuning the experimental parameters during aluminum anodization, these structures were increasingly used as a template for the deposition and growth of large varieties of 1D functional materials. For some time, such self-organized oxide structures seemed to be limited to Al2O3, but in 1999 Zwilling et al. reported self-organized oxide structures (aligned nanotubes) anodically grown on Ti in a dilute fluoride solution. Dilute fluoride electrolytes were then found suitable to grow ordered tubular or porous oxides on a large range of other metals and alloys. Subsequently, the control over the morphology (diameter, length, smoothness of the walls) was strongly improved by continuously optimizing the anodizing conditions. Most research work has been directed towards TiO2 nanotubes, as TiO2 with its semiconductive nature makes the nanotubular structures promising for use in solar cells, photocatalysis and sensors, and also its ion insertion properties and its high degree of biocompatibility have attracted wide interest. The experimental optimization of growth parameters led to various semi-quantitative or qualitative models that provide a mechanistic reasoning for the occurrence of self-organization. Although theoretical modeling of self-ordered structures grown anodically on valve metals was increasingly refined, a main source of difficulty remained, namely the multitude of experimental factors which influence the growth of self-ordered nanostructures. The present work represents an attempt to provide a detailed experimental view over the growth of TiO2 nanotubes in organic electrolytes. The first part is based on describing the methods and set-ups used for growth and characterization of this nanostructure. It draws attention to important aspects that should be considered when using organic electrolytes, poses specific questions regarding the electrochemical methods and provides some solutions to them. The second part is focused on the growth of TiO2 nanotubes under different conditions. This part deals with a wide range of parameters that influence the formation of nanotubes, their chemical composition, geometry, etc. The most important factors in nanotube growth were found to be the applied voltage, water content, temperature and background electrolyte. Oxidation and metal ion dissolution are reactions governing the anodic process and the efficiency of oxide growth which is directly connected with these reactions determines whether self-ordering takes place or not. Many high-end technologies such as scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy were adopted for the detailed characterization of the nanotubes. In the third part, the crystallization of “as grown” amorphous TiO2 nanotubes is addressed. In addition to the influence of well-known annealing parameters (final temperature, heating ramp-rate) on nanotube crystallization, some specific aspects are provided which may drastically affect the efficiency of devices based on TiO2 nanotubes. Here it is shown that heat treatment can be successfully used to control the size of the anatase crystals inside nanotube walls or to alter completely the nanotubular structure. In the last chapter, advanced nanostructures based on TiO2 nanotubes are investigated. Many of these nanostructures are formed via manipulation of electrochemical parameters such as the applied voltage or the chemical etching. Novel “nanolace” and “bamboo-type nanotube” structures are shown and characterized here. In order to demonstrate the advantageous features of these nanotubes, some applications were designed and are described in this part. Specifically featured nanotubular membranes showed good electrochromic, photocatalytic and filtering properties, successfully proving the advantages and the great potential hidden in the ordered nanostructures based on titanium dioxide.Seit über 50 Jahren ist das Interesse von Wissenschaft und Technik an der Anodisierung von Metallen und den dabei beobachteten Phänomenen der Selbstordnung in porösen Oxidfilmen ungebrochen. Vor allem seitdem Masuda et al. die Herstellung von hochgeordneten porösen Aluminiumoxidschichten durch ein Feintuning der Prozessparameter während der Anodisierung von Aluminium gezeigt haben, werden diese Strukturen vermehrt als Template für die Abscheidung und das Wachstum für eine Vielzahl von eindimensionalen anwendungsorientierten Materialien verwendet. Für eine geraume Zeit nahm man an, dass solche selbstorganisierten Oxidstrukturen auf Al2O3 beschränkt sind. 1999 jedoch berichteten Zwilling et al. über das anodische Wachstum von selbstorganisierten Oxidstrukturen (ausgerichteten Nanoröhren) auf Titan in verdünnten Fluorid-Lösungen. Diese verdünnten Fluorid-Lösungen erwiesen sich als besonders geeignet, um geordnete tubulare oder poröse Oxide auf weiteren Metallen und Legierungen aufwachsen zulassen. Über die letzten Jahre hinweg konnte durch eine stetige Optimierung der Anodisierungsbedingungen die Kontrolle über die Morphologie der Nanoröhrenschichten (Durchmesser, Länge, Rauhigkeit der Röhrenwände) stark verbessert werden. Der größte Teil der Forschungsarbeiten auf diesen Gebiet beschäftigt sich mit TiO2 Nanoröhren, da die Kombination der Eigenschaften von halbleitendem TiO2 mit dieser Nanoröhrenstruktur sich als besonders vielversprechend für Anwendungen in Solarzellen und in der Photokatalyse erwiesen. Auch eine Verwendung aufgrund der Ioneneinlagerungseigenschaften und der sehr hohen Biokompatibilität stieß auf breites Interesse. Die experimentielle Optimierung der Wachstumsparameter führte zu verschiedensten semiquantitativen und qualitativen Modellen, die den mechanistischen Hintergrund für das Auftreten von Selbstordnung lieferten. Obwohl die theoretische Modellierung des anodischen Wachstums von selbstgeordneten Strukturen auf Refraktärmetallen zunehmend verfeinert wurde, liegt die größte Herausforderung immer noch in der Komplexität des Systems selbst, d.h. im Zusammenspiel der vielen unterschiedlichen experimentellen Parameter die das Wachstum von selbstgeorneten Nanostrukturen beeinflussen. Die vorliegende Arbeit liefert eine detaillierte Zusammenfassung über das experimentelle Wachstum von TiO2 Nanoröhren in organischen Elektrolyten. Im ersten Teil der Arbeit werden verwendete Methoden und Versuchsaufbauten für das Wachstum und die Charakterisierung dieser Nanostrukturen beschrieben. Besondere Aufmerksamkeit wird dabei auf die wichtigsten Aspekte zur Verwendung von organischen Elektrolyten gelegt und Lösungswege für die damit verbundenen elektrochemischen Herausforderungen dargelegt. Der zweite Teil beschäftigt sich vertiefend mit dem Wachstum von TiO2 Nanoröhren unter verschiedenen Bedingungen. In einer Zusammenstellung wird mit Hilfe einer großen Anzahl von Versuchsparametern deren Auswirkung auf das Nanoröhrenwachstum, die chemische Zusammensetzung und Geometrie der Nanoröhren diskutiert. Es konnte gezeigt werden, dass die wichtigsten Faktoren für das Nanoröhrenwachstum die angelegte Spannung, der Wassergehalt, die Temperatur und die grundsätzliche Zusammensetzung des Elektrolyten sind. Dadurch konnte eine Verbindung zwischen den vorliegenden Oxidations- und Metallauflösungsreaktionen während des anodischen Prozesses, der Effizienz des Oxidwachstums und dem Phänomen der Selbstordnung gefunden werden. Dazu wurden eine Vielzahl an Charakterisierungsmethoden wie Rasterelektronenmikroskopie, Energiedispersive Röntgenspektroskopie und Transmissionselektronenmikroskopie herangezogen. Der dritte Teil der Arbeit untersucht die Kristallisationseigenschaften der im Ausgangszustand amorphen TiO2 Nanoröhren. Neben dem bereits bekannten Einfluß der „Annealingparameter“ (Endtemperatur, Heizrate) auf die Kristallation der Nanoröhren werden zusätzlich einige spezifische Aspekte gezeigt, die einen drastischen Effekt auf die Effizienz von TiO2 Nanoröhren basierenden Anwendungen haben könnten. Hierbei wird gezeigt, dass die Temperaturbehandlung dazu genutzt werden kann die Größe der Anatas Kristallite in den Nanoröhrenwänden einzustellen oder die komplette Nanoröhrenstruktur zu verändern. Im letzten Kapitel werden fortgeschrittene Nanostrukturen basierend auf TiO2 Nanoröhren untersucht. Viele dieser Nanostrukturen werden durch Verändern der elektrochemischen Parameter, z.B. der angelegten Spannung oder Änderungen in der chemischen Ätzrate, gebildet. Hierin werden diese neuartigen „Nanolace“ und „bamboo-type nanotubes“ gezeigt und charakterisiert. In diesem Bereich werden, um die herausragenden Eigenschaften dieser Nanoröhrenschichten zu demonstrieren, einige Anwendungen entworfen und beschrieben. Speziell eingestellte Nanoröhrenmembranen zeigten herausragende elektrochrome, photokatalytische und Filtereigenschaften, welche die Vorteile und das verborgene, den geordneten TiO2 Nanostrukturen innewohnende Potential zum Vorschein bringen

Mechanism of Early Stage Corrosion for Boric-sulfuric Acid Anodized 2A97 Al-Cu-Li Alloy Under Tropical Marine Atmosphere

Optical microscopy(OM), scanning electron microscopy(SEM), EDX and EIS combined with ultramicrotomy were employed to investigate the micro morphology, chemical composition and electrochemical properties of anodized 2A97 Al-Cu-Li alloy before and after atmospheric corrosion. The results show that when electrolytes containing combinations of tartaric-sulfuric or boric-sulfuric acid are used to grow the films at different temperatures, boric acid addition and higher temperature allow for higher current density that speeds up the film growth. The pore geometry and structure is similar for different electrolytes. Dispersive dark rusty spots composed of O, Al, Cl, Cu are present on the boric-sulfuric acid anodized specimen after exposure in tropical marine atmosphere for 1 month. Deposition of white corrosion product is found on the specimen surface as well. Severe pitting occurs and develops deeply into the alloy substrate after elongated outdoor exposure. Corrosion propagation is associated with θ-phase particles

Transport properties of single TiO2 nanotubes

We investigated the electric transport properties of single TiO2 nanotubes separated from an anodic titania nanotube array. The temperature dependence of the resistance measured with the conventional four point method of all investigated samples show a Mott variable range hopping behavior. The results obtained with two contacts indicate the existence of a potential barrier between the Cr/Au contacts and samples surfaces, which influence is clearly observable at temperatures <150 K. Impedance spectroscopy in the frequency range of 40 Hz to 1 MHz carried out at room temperature indicates that the electronic transport of these polycrystalline tubes is dominated by the grain cores

Excited state properties of anodic TiO2 nanotubes

Charge carriers, that is, holes as well as trapped and “free” electrons were investigated by means of time resolved spectroscopy in anodic TiO2 nanotubes that were heat treated at different temperatures. The lifetimes of the charge carrier were compared with those generated in reference layers of Solaronix Ti-Nanoxide D and Degussa P25 nanoparticles. Remarkably long lived “free” electrons were only noted in the TiO2 nanotubes. These findings have significance in view of any photoelectrochemical applications of TiO2 nanotubes

Communication-observation of arrhenius behavior of catholyte stability in vanadium flow batteries

The stability of typical vanadium flowbattery (VFB) catholytes with respect to precipitation of V2O5 was investigated at temperatures in the range 30–60◦C. In all cases a precipitate formed after an induction time, which decreased with increasing temperature and concentration of VV and increased with concentration of sulfate. Arrhenius-type plots are shown for two typical solutions. These have excellent linearity and have similar slopes which yield an apparent activation energy of 1.79 eV (172 kJ mol−1). The variation of induction time with temperature for various concentrations of VV was simulated, and stability diagrams for additive-free VFB catholytes were generated