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In this work we computed the phase diagram as a function of temperature and doping for a system of lead adatoms allocated periodically on a silicon (111) surface. This Si(111):Pb material is characterized by a strong and long-ranged Coulomb interaction, a relatively large value of the spin-orbit coupling, and a structural phase transition that occurs at low temperature. In order to describe the collective electronic behavior in the system, we perform many-body calculations consistently taking all these important features into account. We find that charge- and spin-density wave orderings coexist with each other in several regions of the phase diagram. This result is in agreement with the recent experimental observation of a chiral spin texture in the charge density wave phase in this material. We also find that geometries of the charge and spin textures strongly depend on the doping level. The formation of such a rich phase diagram in the Si(111):Pb material can be explained by a combined effect of the lattice distortion and electronic correlations.

Derzeit besteht eine große methodische Lücke zwischen den numerischen Instrumenten, die in den ab-initio rechnergestützten Materialwissenschaften verwendet werden, und den Methoden, welche eingesetzt werden, um die Auswirkungen starker Korrelationen zu untersuchen.Erstere sind in der Lage, realistische große Systeme zu behandeln, während letztere sich auf Modelle mit geringerer Anzahl an Freiheitsgraden konzentrieren, die sehr akkurat gelöst werden können.Das Ziel vorliegender Arbeit besteht darin, Instrumente zu entwickeln, die eine Brücke zwischen diesen beiden Ansätzen bilden. Um dieses Ziel zu erreichen, wurde der Pfad der dualen Theorien starker Korrelationen (Theorie dualer Fermionen und Bosonen) gewählt, welche diagrammatische Erweiterungen der dynamischen Molekularfeldtheorie sind. Die dualen Theorien beruhen auf der Aufteilung eines großen Systems in zwei Teile, d.h. in eine lokale Störstelle und einen nichtlokalen Teil. Dadurch wird das Anfangsproblem auf ein effektives Referenzproblem reduziert, welches exakt gelöst werden kann. In dieser Hinsicht gehören die dualen Theorien zur Klasse der quantenmechanischen Einbettungsmethoden.Das erste wichtige Resultat vorliegender Arbeit ist die Erweiterung einer Approximation der Theorie dualer Bosonen, die als D-TRILEX-Theorie bezeichnet wird. Die D-TRILEX-Theorie ist aus numerischer Sicht besonders attraktiv, da sie die Komplexität der Berechnung nichtlokaler, starker Korrelationen auf die Komplexität einer GW-Theorie reduziert und gleichzeitig exakte lokale Vertexkorrekturen nicht-störungstheoretisch berücksichtigt. Ein weiterer Großteil vorliegender Arbeit wurde der Implementierung eines effizienten Codes gewidmet, welcher die Berechnung von Multi-Band-Systeme mit mehreren Orbitalen mittels der D-TRILEX-Theorie ermöglicht. Obwohl physikalische Argumente zugunsten der D-TRILEX-Näherung vorgebracht werden können, ist ihr Gültigkeitsbereich nicht a-priori bekannt. Folglich wird ein Benchmark benötigt, um die Genauigkeit und die Grenzen des Anwendungsbereiches bewerten zu können.Des Weiteren stellt ein wesentlicher Bestandteil der vorliegenden Dissertation die Implementierung eines diagrammatischen Monte-Carlo-Schemas für die Theorie dualer Bosonen (DiagMC@DB) dar, die es erlaubt, alle Feynman-Diagramme der Theorie zusammenzufassen. In einer detaillierten Diskussion betrachten wir, wie die Analyse dieser Methode Ordnung-für-Ordnung es ermöglicht, Informationen über Phasenübergänge zu extrahieren. Insbesondere fassen wir die Instabilität der Ladungsdichtewellen des erweiterten Hubbard-Modells ins Auge. Später wurde DiagMC@DB verwendet, um die Genauigkeit der D-TRILEX Methode für das Hubbard-Modell mit einem Orbital (dotiert und bei halber Füllung), sowie für das erweiterte Hubbard-Modell mit nichtlokalen Wechselwirkungen zu untersuchen. Dabei wurden Bereiche ermittelt, in denen die D-TRILEX-Theorie die Ergebnisse der Theorie dualer Bosonen in guter Genauigkeit reproduziert.Ein weiterer wichtiger Teil dieser Arbeit besteht darin, die Gültigkeit dieser Näherung an einem System mit mehreren Orbitalen zu untersuchen. Der Grund dafür ist, dass leider nur wenige exakte Lösungen für solche Systeme bestehen. Deswegen haben wir die D-TRILEX-Methode mit der exakten Diagonalisierung für ein System mit mehreren Orbitalen bestehend aus einem Dimer verglichen. Dabei haben wir sehr genaue Übereinstimmungen in den Ergebnissen festgestellt, obwohl für solch einniederdimensionales System erwartet wird, dass DMFT kein gutes Referenzsystem ist. Außerdem haben wir sie mit der dynamischen Vertex-Approximation DΓA) für ein Modell mit zwei Orbitalen auf einem Gitter verglichen.Im letzten Teil diskutieren wir zwei Anwendungen der D-TRILEX-Methode. Die erste Anwendung besteht darin, Bleiadatomen auf einer Siliziumoberfläche zu untersuchen, wobei langreichweitige Wechselwirkungen und Fluktuationen entscheidend für die Beschreibung der Eigenschaften des Systems sind. Als zweite Anwendung untersuchen wir eine hoch interessante Situation, in der die Einbeziehung von nichtlokalen Fluktuationen das Bild einer rein lokalen Beschreibung der Korrelationen erheblich verändert und zu einer ausgedehnten Region mit koexistierenden metastabilen metallischen und isolierenden Phasen führt. There is currently a large methodological gap between the numerical tools used in ab-initio computational materials science and the methods used to investigate the effects of strong correlations.The former can treat realistic large-scale systems, while the latter focus on models with few degrees of freedom that can be solved very accurately.The purpose of this thesis is to develop tools that act as a bridge between these two approaches.The route chosen in this thesis is the dual theories of strong correlations (dual fermion and dual boson theories), that are diagrammatic extensions of the dynamical mean field theory.The dual theories rely on dividing a large system into two parts, an impurity and a non-local part, reducing the initial problem into an effective reference problem that can be solved exactly. From this perspective, the dual theories effectively belong to the class of quantum embedding methods.As first major result of this thesis, we extend an approximation of the dual boson theory, named D-TRILEX theory, to the multi-band framework. D-TRILEX is particularly attractive from a computational point of view, because it reduces the complexity of the calculation of non-local strong correlations to that of a GW calculation, while including exact local vertex corrections non-perturbatively. The development of this theory allowed us to implement an efficient code for multi-orbital and multi-site D-TRILEX calculations. Even though physical arguments can be made in favor of the D-TRILEX approximation, its regime of validity is not \emph{a-priori} known. As a consequence, a benchmark is needed to assess its accuracy and limitations.To this aim, an important portion of this work consisted in the implementation of a diagrammatic Monte Carlo scheme for the dual boson theory (DiagMC@DB), that allows to sum up all the Feynman diagrams of the theory in an unbiased way.We show that the order-by-order analysis of this method allows to extract information about phase transitions, in particular a charge density wave instability in the extended Hubbard model.We use the DiagMC@DB at later stages to assess the accuracy of the D-TRILEX method for the single-orbital Hubbard model at half-filling and in the doped regime, as well as for the extended Hubbard model with non-local interactions. Based on this analysis, we identify the regimes where it accurately reproduces the dual boson results.Moreover, we investigate the validity of the approximations in a multi-orbital framework, where exact results are rare. Specifically, we compare the D-TRILEX method with exact diagonalization for a multi-orbital dimer system, finding very accurate results even for this low-dimensional system, where the impurity problem is not a good reference system. we also present an additional comparison with the dynamical vertex approximation (DΓA) for a two-orbital model on a lattice.In the last part, we discuss two applications of the D-TRILEX method. The first consists in the study of lead adatoms (Pb) on a silicon surface, where long-range interactions and fluctuations are crucial to describe the properties of the system.As a second application, we investigate an intriguing situation where the inclusion of non-local fluctuations significantly changes the picture provided by a purely local description of the correlations and leads to an extended region of coexisting metastable metallic and insulating phases.

We present the multi-band dual triply irreducible local expansion (D-TRILEX) approach to interacting electronic systems and discuss its numerical implementation. This method is designed for a self-consistent description of multi-orbital systems that can also have several atoms in the unit cell. The current implementation of the D-TRILEX approach is able to account for the frequency- and channel-dependent long-ranged electronic interactions. We show that our method is accurate when applied to small multi-band systems such as the Hubbard-Kanamori dimer. Calculations for the extended Hubbard, the two-orbital Hubbard-Kanamori, and the bilayer Hubbard models are also discussed.

Enzymes, as natural and potentially long-term treatment options, have become one of the most sought-after pharmaceutical molecules to be delivered with nanoparticles (NPs), however, their instability during formulation often leads to underwhelming results. Various molecules, including the Tween® polysorbate series, have demonstrated enzyme activity protection but are often used uncontrolled without optimization. Here, poly(lactic-co-glycolic) acid (PLGA) NPs loaded with β-glucosidase (β-Glu) solutions containing Tween® 20, 60, or 80 were compared. Mixing the enzyme with Tween® pre-formulation had no effect on particle size or physical characteristics, but increased the amount of enzyme loaded. More importantly, NPs made with Tween® 20:enzyme solutions maintained significantly higher enzyme activity. Therefore, Tween® 20:enzyme solutions ranging from 60:1 to 2419:1 mol:mol were further analyzed. Isothermal titration calorimetry analysis demonstrated low affinity and unquantifiable binding between Tween® 20 and β-Glu. Incorporating these solutions in NPs showed no effect on size, zeta potential, or morphology. The amount of enzyme and Tween® 20 in the NPs was constant for all samples, but a trend towards higher activity with higher molar rapports of Tween® 20:β-Glu was observed. Finally, a burst release from NPs in the first hour with Tween®:β-Glu solutions was the same as free enzyme, but the enzyme remained active longer in solution. These results highlight the importance of stabilizers during NP formulation and how optimizing their use to stabilize an enzyme can help researchers design more efficient and effective enzyme loaded NPs.

Cannabidibutol (CBDB), a novel butyl analog of cannabidiol, was identified as impurity of commercial cannabidiol (CBD) extracted from hemp (for full data and results interpretation see “Analysis of impurities of cannabidiol from hemp. Isolation, characterization and synthesis of cannabidibutol, the novel cannabidiol butyl analog” Citti et al, 2019). The compound was isolated from a CBD sample and subject to a full characterization. First, a complete spectroscopic characterization was performed by Nuclear Magnetic Resonance (NMR): in particular, 1H-NMR, 13C-NMR, COSY, HSQC and HMBC, which were followed by UV absorption and circular dichroism (CD) spectra. In order to confirm the structural identity and stereochemistry of the compound, a stereoselective synthesis of the trans isomer (1R,6R) was carried out and all the chemical and spectroscopic properties were analyzed. The synthesized compound was characterized by NMR (1H-NMR, 13C-NMR, COSY, HSQC and HMBC), Infra-Red spectroscopy (IR), UV and CD absorption, matching the results obtained for the natural isolated compound. With the analytical standard in hand, a simple high-performance liquid chromatography method coupled to UV detection (HPLC-UV) was developed and validated in house in terms of linearity, accuracy, precision, dilution integrity and stability. The present data might be useful to any researcher or industry that may run into a very common impurity of CBD extracted from hemp, so it can be easily compared with their own experimental data. Keywords: Cannabidiol-C4, Chemical and spectroscopic characterization of cannabidibutol, HPLC-UV method validation, NMR spectra, Circular dichroism, UV absorption

Commensurability effects play a crucial role in the formation of electronic properties of novel layered heterostructures. The interest in these moiré superstructures has increased tremendously since the recent observation of a superconducting state (Nature 2018, 556, 43-50) and metal-insulator transition (Nature 2018, 556, 80-84) in twisted bilayer graphene. In this regard, a straightforward and efficient experimental technique for detection of the alignment of layered materials is desired. In this work, we use optical second harmonic generation, which is sensitive to the inversion symmetry breaking, to investigate the alignment of graphene/hexagonal boron nitride heterostructures. To achieve that, we activate a commensurate-incommensurate phase transition by a thermal annealing of the sample. We find that this structural change in the system can be directly observed via a strong modification of a nonlinear optical signal. Unambiguous interpretation of obtained results reveals the potential of a second harmonic generation technique for probing of structural changes in layered systems. Copyright © 2020 American Chemical Society. The authors thank Chris Berkhout for technical support in nonlinear measurements. The authors also thank Clement Dutreix and Vladimir Kukushkin for fruitful discussions and useful comments. The work of E.A.S. was supported by the Russian Science Foundation, Grant 17-72-20041. K.S.N. acknowledges support from EU Graphene Flagship Program (Contract CNECTICT-604391), European Research Council Synergy Grant Hetero2D, the Royal Society, EPSRC Grant EP/N010345/1. The work of M.I.K. was supported by European Research Council via Synergy Grant 854843 - FASTCORR.

Male patients, especially the young, are at a higher risk of recurrent venous thromboembolism (RVTE) than females. Recent scientific reports show the use of D-dimer does not help predict RVTE risk in males. In the present report, we reviewed the data obtained in the DULCIS study (main report published in Blood 2014), focusing on D-dimer results recorded in non-elderly patients of both genders included in the study, and their relationship with RVTE events occurring during follow-up. Using specifically designed cutoff values for positive/negative interpretation, serial D-dimer measurements (performed during warfarin treatment and up to 3 months after discontinuation of anticoagulation) in 475 patients (males 57.3%) aged ≤ 65 years were obtained. D-dimer resulted positive in 46.3% and 30.5% of males and females, respectively (p = 0.001). Following management procedure, anticoagulation was stopped in 53.7% of males and 69.5% of females, who had persistently negative D-dimer results. The rate of subsequent recurrent events was 1.7% (95% CI 0.5–4.5%) and 0.4% (95% CI 0–2.5%) patient-years in males and females, respectively, with upper limits of confidence intervals always below the level of risk considered acceptable by international scientific societies for stopping anticoagulation (

The effect of the concentration of a cross-linking agent (gelatin hardener) on gelatin microspheres was evaluated. A concentration increase of the gelatin hardener (formaldehyde) produced a decrease of drug loading, swelling degree and drug release rate. The cross-linking agent concentration affected also the kinetics of water absorption and drug release. This paper suggests a decreasing significance of the diffusion-type mechanism of drug release as the concentration of the cross-linking agent increased.