Atom-by-atom condensation in and electronic modification of 2D quantum box arrays

In this thesis the influence of adsorbates on quantum states and vice versa is investigated. The approach taken is that regular porous networks have been produced by means of on-surface self-assembly. Each pore contains a characteristic confined state derived from substrate electrons, thus constituting a quantum box. Importantly, the boxes are electronically coupled with each other, creating quantum box arrays. Here it is shown for the first time that the quantum boxes can be used as nano-beakers offering insight into the condensation atom-by-atom (Chapter [[1]]) and that the quantum states in the boxes can be controllably modified locally as well as globally by adding adsorbates (Chapter [[2,3]]). The structural characterization of those systems with sub-atomic/sub-molecular resolution was performed by scanning tunnelling microscopy (STM), whereas the electronic properties were investigated by complementary techniques: locally by scanning tunneling spectroscopy (STS) and globally by angle-resolved photoemission spectroscopy (ARPES). In Chapter [[1]] the condensation behaviour of xenon in quantum boxes has been investigated in depth. For these studies a quantum box array, formed by a metal-coordinated network of perylene-derived molecules self-assembled on Cu(111), was exposed to xenon. STM studies revealed, that xenon atoms adsorb in the quantum boxes and each occupancy from 1 to 12 is observed. In this way the condensation of xenon has been monitored in an atom-by-atom manner. The analysis of the condensates’ structure revealed different sets of ‘hierarchic filling rules’ governing the condensation in low and high occupancy regimes. It was concluded that the condensation is governed by the subtle interplay of weak interactions occurring with (1) the underlying substrate (registry), (2) the border of the quantum box and (3) the electronic quantum box state. Condensation events in the low occupancy regime, i.e. from one to six xenon atoms per pore, occur solely at the border of the pore. In combination with xenon repositioning sequences conclusion has been drawn about the repulsive interaction between xenon and the quantum box state. The occupancy histogram spectacularly revealed the existence of more frequently observed, thus particularly stable occupancies, i.e. ‘magic’ condensates. The detailed evolution of the xenon clustering in the quantum boxes also constitutes a system to evaluate different models for first principle calculations. In the second study (Chapter [[2]]) the influence of adsorbates on a quantum box state was investigated by dosing and controlled removal of xenon in quantum box arrays formed by a metal-coordinated network of perylene-derived molecules self-assembled on Cu(111). Thus the opposite dependence, i.e. how adsorbates influence electronic quantum box state, compared to the first study (Chapter [[1]]) has been studied with the same model system. The occupancy of xenon in the quantum boxes was controlled here by STM repositioning of individual xenon atoms. Remarkably decrementing the xenon occupancy discretely changes the ground state energy of the quantum box, i.e. shifts it towards higher binding energies, due to the reduced Pauli repulsion. In this way the electronic states embedded in the array could be configured: xenon-by-xenon. Another important feature investigated is the interaction between neighbouring quantum boxes. By analysing the electronic states in specific patterns of empty and xenon-filled pores unambiguous evidence has been provided that the electronic state in a given quantum box depends also on the electronic states of the surrounding boxes. On the basis of these pioneering investigations and results, a quantum box array can be viewed as a quantum breadboard opening up the possibility of configuring electronic quantum states by combining different adsorbates exerting distinct influence on these states. Another important property of a quantum box array is the transmission coefficient of the confining barrier describing in this case the probability of an electron to tunnel between the neighbouring quantum boxes, as it determines the strength of the inter-box coupling. In the third study (Chapter [[3]]) it is demonstrated that the transmission coefficient of the barrier can be also modified by adsorbates. Here the investigated quantum array was formed by a porphyrin network held by C−H···F−C interactions self-assembled on Ag(111). This array exhibits the quantum box state above the Fermi level, contrary to the array formed from the metal-coordinated network of perylene-derived molecules self-assembled on Cu(111) (Chapter [[2]]). The existence of the inter-box coupling in the porphyrin array was also confirmed by combined STS/ARPES measurements. Notably, these are the first ARPES studies of a molecular array featuring its confined state above the Fermi level. The porphyrin building block exhibits two different barrier regions, i.e. the porphyrin macrocycle and the pentafluorophenyl substituents, which interact differently with the quantum states. To modify the transmission probability of the barrier regions two adsorbates exhibiting characteristically different electronic properties were investigated, i.e. xenon and C60 fullerene. The STM revealed two xenon atoms adsorbed on the porphyrin macrocycle and one or two C60 molecules adsorbed in the pore. Xenon interacting with the barrier by weak van der Waals forces did not detectably affect the transmission probability, while the strong electron acceptor C60 reduced the transmission probability significantly. These results demonstrate that the interaction between neighbouring quantum boxes can be tuned by the appropriate selection of adsorbates. This work established a radically new approach to engineer coupled quantum states in quantum boxes embedded in on-surface porous networks. Moreover, it is shown that the quantum boxes can be used as nano-beakers, offering real-space access to the condensation proceeding under the interplay of weak interactions in an atom-by-atom way

Solid polymer composition

The present invention relates in a first aspect to a solid polymer component comprising luminescent crystals of 3-500 nm size, surfactant and a hardened/cured polymer. In a second aspect of the invention, a luminescent component comprises a first element comprising the solid polymer component according to the first aspect and an encapsulation enclosing the first element. In a third aspect of the invention, a luminescent component comprises a first film comprising the solid polymer composition of the first aspect. A fourth aspect of the invention relates to a light emitting device comprising the luminescent component according to the second or third aspect of the invention and a light source.</p

Clara Cell protein and myeloperoxidase levels in serum of subjects after exposure to fire smoke

Introduction. Fire smoke inhalation is a well-recognized aetiological factor of airway injuries. The objective of this study was evaluation of Clara cell protein (CC16) and myeloperoxidase (MPO) concentrations in serum of patients after exposure to uncontrolled fire smoke. Methods. The study group consisted of 40 consecutive patients admitted to the Toxicology Unit after exposure to fire smoke. CC16 and MPO concentrations in their serum samples was measured on the day of admission to hospital and rechecked at the 2nd day and on the day of discharge. Patients also underwent routine toxicological diagnostic procedures applied in case of exposures, such as carboxyhaemoglobin (COHb) levels and blood lactate and urinary thiocyanate concentrations. The same diagnostic tests were performed in the control group consisting of 10 healthy subjects not exposed to fire smoke. Results. The average concentration of CC16 in the serum of subjects exposed to toxic factors was significantly higher at the day of admission in comparison with the respective values recorded on the 2nd day and on the day of discharge. The mean level of CC16 in the serum of the exposed group was also significantly higher than that in the control group. Tests for MPO concentrations in the serum did not reveal any significant changes in patients exposed to fire smoke. Conclusions. As indicated, acute exposure to smoke induces injury at the alveolar level, which results in a transient increase of CC16 in serum of exposed subjects.Wstęp. Narażenie na dymy pożarowe jest udokumentowaną przyczyną toksycznego uszkodzenia układu oddechowego. Celem badania była ocena stężeń bialka Clara i mieloperoksydazy w surowicy osób narażonych na dymy pożarowe.Metody. Grupę badaną stanowiło 40 osób narażonych na dymy pożarowe, które zostały przyjęte na oddział toksykologii. Stężenia białka Clara i mieloperoksydazy oznaczono w dniu przyjęcia do szpitala oraz ponownie w drugim i ostatnim dniu hospitalizacji. U pacjentów wykonano także badania toksykologiczne zlecane przy tego typu narażeniu: stężenie karboksyhemoglobiny i stężenie mleczanów we krwi oraz stężenie rodanków w moczu. Podobny panel badań zlecono u 10 zdrowych osób (grupa kontrolna) nienarażonych na dymy pożarowe. Wyniki. Stężenie białka Clara było istotnie statystycznie wyższe w surowicy pacjentów narażonych na dymy pożarowe w dniu ich przyjęcia do szpitala w porównaniu z wartością tego parametru ocenianego w drugim i ostatnim dniu hospitalizacji. Stężenie białka Clara było również istotnie wyższe w surowicy osób narażonych w porównaniu z grupą kontrolną. Nie obserwowano istotnych zmian steżenia MPO w surowicy osób eksponowanych na dymy pożarowe. Wnioski. Narażenie na dymy pożarowe może prowadzić do uszkodzenia pęcherzyków płucnych, a tym samym do wzrostu w surowicy osób narażonych stężenia białka Clara uwalnianego przez te komórki

T1−T2T_{1}-T_{2} dual-modal MRI contrast agents based on superparamagnetic iron oxide nanoparticles with surface attached gadolinium complexes

Dual-mode MRI contrast agents consisting of superparamagnetic iron oxide nanoparticle (SPION) cores and gadolinium ions associated with the ionic chitosan protecting layer were synthesized and studied. Gadolinium ions were introduced into the coating layer via direct complex formation on the nanoparticles surface, covalent attachment or electrostatically driven deposition of the preformed Gd complex. The modified SPIONs having hydrodynamic diameters ca. 100 nm form stable, well-defined dispersions in water and have excellent magnetic properties. Physiochemical prop- erties of those new materials were characterized using e.g., FTIR spectroscopy, dynamic light scattering, X-ray fluorescence, TEM, and vibrating sample mag- netometry. They behave as superparamagnetics and shorten both T 1 and T 2 proton relaxation times, thus influencing both r 1 and r 2 relaxivity values that reach 53.7 and 375.5 mM - 1 s - 1 , respectively, at 15 MHz. The obtained materials can be considered as highly effective contrast agents for low-field MRI, particu- larly useful at permanent magnet-based scanners

Configuring electronic states in an atomically precise array of quantum boxes

Communication.-- et al.A 2D array of electronically coupled quantum boxes is fabricated by means of on-surface self-assembly assuring ultimate precision of each box. The quantum states embedded in the boxes are configured by adsorbates, whose occupancy is controlled with atomic precision. The electronic interbox coupling can be maintained or significantly reduced by proper arrangement of empty and filled boxes.The authors would like to acknowledge financial support from the Swiss Nanoscience Institute (SNI), Swiss National Science Foundation (Grants Nos. 200020-149713 and 206021-121461), the Spanish Ministry of Economy (Grant No. MAT2013-46593-C6-4-P), the Basque Government (Grant No. IT621-13), the São Paulo Research Foundation (Grant No. 2013/04855-0), Swiss Government Excellence Scholarship Program, Netherlands Organization for Scientific Research NWO (Chemical Sciences, VIDI-Grant No. 700.10.424), the European Research Council (ERC-2012-StG 307760-SURFPRO), University of Basel, University of Heidelberg, Linköping University, University of Groningen, Paul Scherrer Institute, and the Japan Science and Technology Agency (JST) “Precursory Research for Embryonic Science and Technology (PRESTO)” for a project of “Molecular technology and creation of new function.”Peer Reviewe

Systematic analysis of changes in radiomics features during dynamic breast-MRI: Evaluation of specific biomarkers

OBJECTIVES In this retrospective, single-center study we investigate the changes of radiomics features during dynamic breast-MRI for healthy tissue compared to benign and malignant lesions. METHODS 60 patients underwent breast-MRI using a dynamic 3D gradient-echo sequence. Changes of 34 texture features (TF) in 30 benign and 30 malignant lesions were calculated for 5 dynamic datasets and corresponding 4 subtraction datasets. Statistical analysis was performed with ANOVA, and systematic changes in features were described by linear and polynomial regression models. RESULTS ANOVA revealed significant differences (p < 0.05) between normal tissue and lesions in 13 TF, compared to 9 TF between benign and malignant lesions. Most TF showed significant differences in early dynamic and subtraction datasets. TF associated with homogeneity were suitable to discriminate between healthy parenchyma and lesions, whereas run-length features were more suitable to discriminate between benign and malignant lesions. Run length nonuniformity (RLN) was the only feature able to distinguish between all three classes with an AUC of 88.3%. Characteristic changes were observed with a systematic increase or decrease for most TF with mostly polynomial behavior. Slopes showed earlier peaks in malignant lesions, compared to benign lesions. Mean values for the coefficient of determination were higher during subtraction sequences, compared to dynamic sequences (benign: 0.98 vs 0. 72; malignant: 0.94 vs 0.74). CONCLUSIONS TF of breast lesions follow characteristic patterns during dynamic breast-MRI, distinguishing benign from malignant lesions. Early dynamic and subtraction datasets are particularly suitable for texture analysis in breast-MRI. Features associated with tissue homogeneity seem to be indicative of benign lesions

Dynamics of superparamagnetic iron oxide nanoparticles with various polymeric coatings

In this article, the results of a study of the magnetic dynamics of superparamagnetic iron oxide nanoparticles (SPIONs) with chitosan and polyethylene glycol (PEG) coatings are reported. The materials were prepared by the co-precipitation method and characterized by X-ray diffraction, dynamic light scattering and scanning transmission electron microscopy. It was shown that the cores contain maghemite, and their hydrodynamic diameters vary from 49 nm for PEG-coated to 200 nm for chitosan-coated particles. The magnetic dynamics of the nanoparticles in terms of the function of temperature was studied with magnetic susceptometry and Mössbauer spectroscopy. Their superparamagnetic fluctuations frequencies, determined from the fits of Mössbauer spectra, range from tens to hundreds of megahertz at room temperature and mostly decrease in the applied magnetic field. For water suspensions of nanoparticles, maxima are observed in the absorption part of magnetic susceptibility and they shift to higher temperatures with increasing excitation frequency. A step-like decrease of the susceptibility occurs at freezing, and from that, the Brown’s and Néel’s contributions are extracted and compared for nanoparticles differing in core sizes and types of coating. The results are analyzed and discussed with respect to the tailoring of the dynamic properties of these nanoparticle materials for requirements related to the characteristic frequency ranges of MRI and electromagnetic field hyperthermia

Role of Lipid Peroxidation Products, Plasma Total Antioxidant Status, and Cu-, Zn-Superoxide Dismutase Activity as Biomarkers of Oxidative Stress in Elderly Prediabetics

The relationship between hyperglycemia and oxidative stress in diabetes is well known, but the influence of metabolic disturbances recognized as prediabetes, in elderly patients especially, awaits for an explanation. Methods. 52 elderly persons (65 years old and older) with no acute or severe chronic disorders were assessed: waist circumference (WC), body mass index (BMI), percentage of body fat (FAT), and arterial blood pressure. During an oral glucose tolerance test (OGTT) fasting (0′) and 120-minute (120′) glycemia and insulinemia were determined, and type 2 diabetics (n=6) were excluded. Subjects were tested for glycated hemoglobin HbA1c, plasma lipids, total antioxidant status (TAS), thiobarbituric acid-reacting substances (TBARS), and activity of erythrocyte superoxide dismutase (SOD-1). According to OGTT results, patients were classified as normoglycemics, (NGT, n=18) and prediabetics, (PRE, n=28). Results. Both groups did not differ with their lipids, FAT, and TBARS. PRE group had higher WC (P<0.002) and BMI (P<0.002). Lower SOD-1 activity (P<0.04) and TAS status (P<0.04) were found in PRE versus NGT group. Significance. In elderly prediabetics, SOD-1 and TAS seem to reflect the first symptoms of oxidative stress, while TBARS are later biomarkers of oxidative stress