BINA

Ni-rich layered oxide LiNi₁ – ₓ – yCoₓMnyO₂ (1 – x – y > 0.5) materials are favorable cathode materials in advanced Li-ion batteries for electromobility applications because of their high initial discharge capacity. However, they suffer from poor cycling stability because of the formation of cracks in their particles during operation. Here, we present improved structural stability, electrochemical performance, and thermal durability of LiNi₀.₈₅Co₀.₁Mn₀.₀₅O₂(NCM85). The Nb-doped cathode material, Li(Ni₀.₈₅Co₀.₁Mn₀.₀₅)₀.₉₉₇Nb₀.₀₀₃O₂, has enhanced cycling stability at different temperatures, outstanding capacity retention, improved performance at high discharge rates, and a better thermal stability compared to the undoped cathode material. The high electrochemical performance of the doped material is directly related to the structural stability of the cathode particles. We further propose that Nb-doping in NCM85 improves material stability because of partial reduction of the amount of Jahn–Teller active Ni³⁺ ions and formation of strong bonds between the dopant and the oxygen ions, based on density functional theory calculations. Structural studies of the cycled cathodes reveal that doping with niobium suppresses the formation of cracks during cycling, which are abundant in the undoped cycled material particles. The Nb-doped NCM85 cathode material also displayed superior thermal characteristics. The coherence between the improved electrochemical, structural, and thermal properties of the doped material is discussed and emphasized.

Pt-Ni nanoparticles (NPs) are used as electrocatalysts toward the oxygen reduction reaction due to their high mass activity. However, degradation processes at the high potential in the acidic conditions of the proton exchange membrane fuel cell delay its massive implementation. The model presented here facilitates understanding the corrosion by clearing variables related to the electrochemical measurement (non-equilibrium condition and complex system) and focusing on the gradual etching of Ni via two-phase Ni(II) transfer treatment promoted by chelating agents (CAs). We synthesized Pt-Ni/C octahedral NPs and then used six chemically different CAs as corrosion agents for Ni. The corrosion yielded concave octahedral and hexapod NPs. Amine-rich CAs treatment results in particle detachment from the carbon substrates, while carboxylic rich preserve the carbon-particle interface. We correlate the detachment …

As magnesium ions have been considered one of the most important cations for numerous physiological and pathological functions since the past century, the selective and specific detection of magnesium ions with chemosensors has drawn considerable interest and became essential in biomedical and biological studies. Herein, we report highly fluorescent boron-doped carbon dots (BCDs) that were synthesized via a simple solvothermal method utilizing catechol as a carbon source and naphthalene boronic acid as the boron source. The obtained BCDs exhibited violet luminescence with a quantum yield of 39.4%, which is higher than that obtained in any previous report. For the first time, the as-prepared BCDs were explored for the highly selective and sensitive detection of Mg2+ ions over Ca2+ ions. This method is based on a fluorescence property resulting from the strong complex formed between Mg2+ and …

The current work presents the fabrication of micrometer‐thick single‐side‐coated surface‐engineered polypropylene (PP) film for versatile flexible electronics applications. Herein, the authors report, for the first time, photopolymerized thin coating of graphene nanofibers (GNFs) and iron oxide nanoparticles (IONPs) onto non‐polar plastic via surface chemistry. The fabrication is achieved by adopting three consecutive steps; initially corona treated PP films are treated with silane for thin layer silica coating. Then, the silylated PP films are brushed up by pyrrole/GNFs/IONPs mixture, followed by UV exposure. The coated films show surface conductivity in the range of ≈20 S cm−1 at room temperature. Moreover, ≈15 microns of the coated film is tested against electromagnetic waves in the X‐band region (8.2–12.4 GHz) and its shielding behavior (≈24 dB) is confirmed. To demonstrate its wide range of versatility, the …

In this paper, we demonstrate a digital micromirror device (DMD) based optical microscopic apparatus for quantitative differential phase contrast (qDIC) imaging, coherent structured illumination microscopy (SIM), and dual-modality (scattering/fluorescent) imaging. For both the qDIC imaging and the coherent SIM, two sets of fringe patterns with orthogonal orientations and five phase-shifts for each orientation, are generated by a DMD and projected on a sample. A CCD camera records the generated images in a defocusing manner for qDIC and an in-focus manner for coherent SIM. Both quantitative phase images and super-resolved scattering/fluorescence images can be reconstructed from the recorded intensity images. Moreover, fluorescent imaging modality is integrated, providing specific biochemical structures of the sample once using fluorescent labeling. We believe such a simple and versatile apparatus will find wide applications in biomedical fields or life science.

mediaTUM - Medien- und Publikationsserver mediaTUM Universitätsbibliothek Technische Universität München Logo Benutzer: Gast Login de en mediaTUM Gesamtbestand Hochschulbibliographie Elektronische Prüfungsarbeiten Open Access Publikationen Forschungsdaten TUM.University Press Sammlungen Projekte Einrichtungen Forschungszentren Hochschulpräsidium Partnerschaftliche Einrichtungen Schools und Fakultäten Fakultät für Chemie Fakultät für Elektrotechnik und Informationstechnik Prüfungsarbeiten (1447) Bildarchiv Lehrstühle und Professuren Audio-Signalverarbeitung (Prof. Seeber) (383) Bioanaloge Informationsverarbeitung (Prof. Hemmert) (304) Biomedizinische Elektronik (Prof. Hayden) (301) Codierung und Kryptographie (Prof. Wachter-Zeh) (342) Computational Neuroengineering (Prof. Cheng komm.) (69) Computational Photonics (W3TT) (Prof. Jirauschek) (234) Control and …

In order to solely rely on renewable and efficient energy sources, reliable energy storage and production systems are required. Hydrogen is considered an ideal solution as it can be produced electrochemically by water electrolysis and renewably while no pollutants are released when consumed. The most common catalysts in electrolyzers are composed of rare and expensive precious group metals. Replacing these materials with Earth-abundant materials is important to make these devices economically viable. Metal organic frameworks are one possible solution. Herein we demonstrate the synthesis and characterization studies of metal benzene-tri-carboxylic acid-based metal–organic frameworks embedded in activated carbon. The conductive composite material was found to be electrocatalytically active for both the oxygen evolution reaction and the hydrogen evolution reaction. Furthermore, several metal …

Exosomes are promising vectors for anti-tumor therapy, due to their biocompatibility, low immunogenicity, and innate ability to interact with target cells. However, promoting clinical application of exosome-based therapeutics requires elucidation of key issues, including exosome biodistribution, tumor targeting and accumulation, and the ability to overcome tumor barriers that limit the penetration of various nano-carriers and drugs. Here, we examined these parameters in exosomes derived from mesenchymal stem cells (MSC-exo) and from the A431 squamous cell carcinoma line (A431-exo), which both have potential use in cancer therapy. Using our novel technique combining gold nanoparticle (GNP) labeling of exosomes and non-invasive computed tomography imaging (CT), we longitudinally and quantitatively tracked the two intravenously-injected exosome types in A431 tumor-bearing mice. CT imaging up to 48 …

Among various renewable energy sources, namely, biomass, solar, wind, hydrothermal and geothermal, biomass standout as an environmentally benign, sustainable and an immediate substitute to fossil based fuels. This is due to the abundance of the carbon source in the form of cellulose in the biomass. Cellulose is the major chemical constituent of terrestrial biomass (40-50 wt.%, percentage by weight) with the other constituents being hemicellulose and lignin. However, owing to the extensive inter and intramolecular hydrogen bonding network existing in the cellulose structure, depolymerization of cellulose to monomeric carbohydrate glucose is nearly two orders of magnitude difficult than the hydrolysis of starch to glucose. The extensive inter and intramolecular hydrogen bonding network that hinders the access of acidic proton of the catalyst to attack the reaction site of β-1, 4 glycosidic bonds of cellulose (the linear homopolymer of glucose) is shown pictorially in Figure 1. The hydrogen bonding network within a single chain of glycose polymer in the cellulose structure is called intramolecular hydrogen bonding while such bonding between two neighbouring linear chains of glucose polymers is called as intermolecular hydrogen bonding. The bond energy of such hydrogen bonding is 2 eV which is nearly 3-6 orders of magnitude higher than microwave energy (1.24 x 10-6–1.24 10-3 eV)[1]. Yet, with the application of unconventional and novel methods of activation like microwave irradiation, the acid catalyzed hydrolysis of biomass (cellulose) to monosaccharides is accelerated by facilitating the access of the acidic proton of the chemical …

A balanced progression through mitosis and cell division is largely dependent on orderly phosphorylation and ubiquitin-mediated proteolysis of regulatory and structural proteins. These series of events ultimately secure genome stability and time-invariant cellular properties during cell proliferation. Two of the core enzymes regulating mitotic milestones in all eukaryotes are cyclin dependent kinase 1 (CDK1) with its coactivator cyclin B, and the E3 ubiquitin ligase anaphase promoting complex/cyclosome (APC/C). Discovering mechanisms and substrates for these enzymes is vital to understanding how cells move through mitosis and segregate chromosomes with high fidelity. However, the study of these enzymes has significant challenges. Purely in vitro studies discount the contributions of yet to be described regulators and misses the physiological context of cellular environment. In vivo studies are …

Following nervous system injuries, such as peripheral or spinal cord injuries, severed nerves must regenerate to reinnervate tissues and restore lost-functionality. In many peripheral nerve injuries surgical intervention is required to bridge the gaps created and facilitate regrowth. The gold standard for peripheral nerve repair remains end-to-end suturing and nerve grafting, yet, these still present unmet challenges and limitation including misalignment of regenerating axons. Following spinal cord injuries currently there are no therapies capable of complete nerve restoration. Tissue engineering strategies include the design of structured tissue-like platforms to support growth and facilitate reconstructions of damaged tissues for both the peripheral and the central nervous systems. In the last two decades efforts to increase accuracy of regeneration through engineering growth-and-alignment promoting platforms …

Nanoparticles having magnetic and fluorescent properties could be considered as a gift to materials scientists due to their unique magneto-optical qualities. Multiple component particles can overcome challenges related with a single component and unveil bifunctional/multifunctional features that can enlarge their applications in diagnostic imaging agents and therapeutic delivery vehicles. Bifunctional nanoparticles that have both luminescent and magnetic features are termed as magnetic nanolights. Herein, we present recent progress of magneto-fluorescent nanoparticles (quantum dots based magnetic nanoparticles, Janus particles, and heterocrystalline fluorescent magnetic materials), comprehensively describing fabrication strategies, types, and biomedical applications. In this review, our aim is not only to encompass the preparation strategies of these special types of magneto-fluorescent nanomaterials but …

Measuring physical phenomena in an experimental system is commonly limited by the detector. When dealing with spatially defined behaviors, the critical parameter is the detector size. In this work, we examine near-infrared (NIR) measurements of turbid media using different size detectors at different positions. We examine cylindrical and semi-infinite scattering samples and measuring their intensity distribution. An apparent crossing point between samples with different scatterings was previously discovered and named the iso-pathlength point (IPL). Monte Carlo simulations show the expected changes due to an increase in detector size or similarly as the detector’s location is distanced from the turbid element. First, the simulations show that the intensity profile changes, as well as the apparent IPL. Next, we show that the average optical pathlength, and as a result, the differential pathlength factor, are mostly influenced by the detector size in the range close to the source. Experimental measurements using different size detectors at different locations validated the influence of these parameters on the intensity profiles and apparent IPL. These findings must be considered when assessing optical parameters based on multiple scattering models. In these cases, such as NIR assessment of tissue oxygenation, the size and location may cause false results of absorption or optical path.

Alu elements are repetitive short interspersed elements prevalent in the primate genome. These repeats account for over 10% of the genome with more than a million highly similar copies. A direct outcome of this is an enrichment in long structures of stable dsRNA, which are the target of adenosine deaminases acting on RNAs (ADARs), the enzymes catalyzing A-to-I RNA editing. Indeed, A-to-I editing by ADARs is extremely abundant in primates: over a hundred million editing sites exist in their genomes. However, despite the radical increase in ADAR targets brought on by the introduction of Alu elements, the few evolutionary conserved editing sites manage to retain their editing levels. Here, we review and discuss the cost of having an unusual amount of dsRNA and editing in the transcriptome, as well as the opportunities it presents, which possibly contributed to accelerating primate evolution.

A balanced progression through mitosis and cell division is largely dependent on orderly phosphorylation and ubiquitin-mediated proteolysis of regulatory and structural proteins. These series of events ultimately secure genome stability and time-invariant cellular properties during cell proliferation. Two of the core enzymes regulating mitotic milestones in all eukaryotes are cyclin dependent kinase 1 (CDK1) with its coactivator cyclin B, and the E3 ubiquitin ligase anaphase promoting complex/cyclosome (APC/C). Discovering mechanisms and substrates for these enzymes is vital to understanding how cells move through mitosis and segregate chromosomes with high fidelity. However, the study of these enzymes has significant challenges. Purely in vitro studies discount the contributions of yet to be described regulators and misses the physiological context of cellular environment. In vivo studies are …

Acute kidney injury (AKI) is frequently associated with reactive oxygen species (ROS) and causes high mortality in clinics annually, and nanotechnology-mediated antioxidative therapy is emerging as a novel strategy for AKI treatment. Herein, four kinds of natural antioxidants are able to coordinate with iron (Fe) ions to form ultra-small coordination polymer nanodots (CPNs) with good water dispersibility and strong ROS scavenging ability. In particular, Fe–curcumin CPNs (Fe–Cur CPNs) are applied for cellular ROS scavenging and rhabdomyolysis-induced AKI relief.

The results of numerical simulation of the near-field distribution inside and in the vicinity of two types of gold nanoparticles (nanospheres and nanorods) intended for producing complexes of gold nanoparticles linked with proteins and exciting photosensitizers in the wavelength range of 532–770 nm are presented. Quantitative estimates of the field localisation (enhancement) are obtained depending on the type of gold nanoparticles and dimensional factors. The tendency of the red shift of the wavelength at which the maximum local field enhancement is achieved relative to the positions of the maxima of the absorption and scattering cross sections of nanoparticles and complexes is described.