Universal quantum dynamics of Bose polarons

Predicting the emergent properties of impurities immersed in a quantum bath is a fundamental challenge that can defy quasiparticle treatments. Here, we measure the spectral properties and real-time dynamics of mobile impurities injected into a homogeneous Bose--Einstein condensate, using two Feshbach resonances to tune both the impurity-bath and intrabath interactions. We map out both attractive and repulsive branches of polaron quasiparticles, resolving the repulsive polaron and the molecular state associated with the Feshbach resonance in the strongly interacting regime, and show that the latter also has a many-body character. Our measurements reveal remarkably universal behavior, controlled by the bath density and a single dimensionless interaction parameter; for near-resonant interactions the polarons are no longer well defined, but the universality still holds.Comment: Main text (6 pages, 5 figures), Supplementary Material (4 pages, 8 figures

Singlet Oxygen In Vivo: It Is All about Intensity—Part 2

Recently, we reported induced anoxia as a limiting factor for photodynamic tumor therapy (PDT). This effect occurs in vivo if the amount of generated singlet oxygen that undergoes chemical reactions with cellular components exceeds the local oxygen supply. The amount of generated singlet oxygen depends mainly on photosensitizer (PS) accumulation, efficiency, and illumination intensity. With illumination intensities above a certain threshold, singlet oxygen is limited to the blood vessel and the nearest vicinity; lower intensities allow singlet oxygen generation also in tissue which is a few cell layers away from the vessels. While all experiments so far were limited to light intensities above this threshold, we report experimental results for intensities at both sides of the threshold for the first time, giving proof for the described model. Using time-resolved optical detection in NIR, we demonstrate characteristic, illumination intensity-dependent changes in signal kinetics of singlet oxygen and photosensitizer phosphorescence in vivo. The described analysis allows for better optimization and coordination of PDT drugs and treatment, as well as new diagnostic methods based on gated PS phosphorescence, for which we report a first in vivo feasibility test.Brigitte and Konstanze Wegener FoundationSojo UniversityGrant-in-Aid for Scientific Research on Scientific Research (C)Ministry of Health of Czech RepublicEuropean Union—Next Generation EUPeer Reviewe

Energy-space random walk in a driven disordered Bose gas

Motivated by the experimental observation [1] that driving a non-interacting Bose gas in a 3D box with weak disorder leads to power-law energy growth, $E \propto t^{\eta}$ with $\eta=0.46(2)$, and compressed-exponential momentum distributions that show dynamic scaling, we perform systematic numerical and analytical studies of this system. Schr\"odinger-equation simulations reveal a crossover from $\eta \approx 0.5$ to $\eta \approx 0.4$ with increasing disorder strength, hinting at the existence of two different dynamical regimes. We present a semi-classical model that captures the simulation results and allows an understanding of the dynamics in terms of an energy-space random walk, from which a crossover from $E \propto t^{1/2}$ to $E \propto t^{2/5}$ scaling is analytically obtained. The two limits correspond to the random walk being limited by the rate of the elastic disorder-induced scattering or the rate at which the drive can change the system's energy. Our results provide the theoretical foundation for further experiments.Comment: Main text (7 pages, 6 figures), Appendices (7 pages, 1 figure

Observation of subdiffusive dynamic scaling in a driven and disordered box-trapped Bose gas

We explore the dynamics of a tuneable box-trapped Bose gas under strong periodic forcing in the presence of weak disorder. In absence of interparticle interactions, the interplay of the drive and disorder results in an isotropic nonthermal momentum distribution that shows subdiffusive dynamic scaling, with sublinear energy growth and the universal scaling function captured well by a compressed exponential. For increasing interaction strength, the gas behavior crosses over to wave turbulence characterized by a power-law momentum distribution.Comment: Main text (4 pages, 4 figures), Supplemental Material (2 pages, 4 figures

Модель смешанного обучения в преподавании дисциплины "Методы получения чистых веществ"

Данная работа посвящена использованию модели смешанного обучения в преподавании дисциплины "Методы получения чистых веществ" на английском языке. Исследовались элементы смешанного обучения, стратегия организации образовательного процесса, план учебной деятельности. Подробно описаны виды учебной деятельности и подобраны формы организации процесса. Для каждого вида деятельности определены уровни таксономии Блума. Показаны преимущества модели смешанного обучения в преподавании лабораторных работ для студентов инженерной специальности

Star Polymer-Drug Conjugates with pH-Controlled Drug Release and Carrier Degradation

In this study, we describe the design, synthesis, and physicochemical and preliminary biological characteristics of new biodegradable, high-molecular-weight (HMW) drug delivery systems with star-like architectures bearing the cytotoxic drug doxorubicin (DOX) attached by a hydrazone bond-containing spacer. The star polymers were synthesized by grafting semitelechelic N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers on a 2,2-bis(hydroxymethyl)propionic acid- (bis-MPA-) based polyester dendritic core. The molecular weight of the star polymers ranged from 280 to 450 000 g/mol and could be adjusted by proper selection of the bis-MPA dendrimer generation and by considering the polymer to dendrimer molar ratio. The biodegradation of the polymer conjugates is based on the spontaneous slow hydrolysis of the dendritic core in neutral physiological conditions. Hydrazone spacers in the conjugates were fairly stable at neutral pH (7.4) mimicking blood stream conditions, and DOX was released from the conjugates under mild acidic conditions simulating the tumor cell microenvironment in endosomes and lysosomes (pH 5). Finally, we have shown the significant in vitro cytotoxicity of the star polymer-DOX conjugate on selected cancer cell lines with IC50 values almost comparable with that of the free drug and higher than that observed for a linear polymer-DOX conjugate with much lower molecular weight

Synthesis and characterization of a multi-arm poly(acrylic acid) star polymer for application in sustained delivery of cisplatin and a nitric oxide prodrug

This is the peer reviewed version of the following article: Duan, S., Cai, S., Xie, Y., Bagby, T., Ren, S. and Forrest, M. L. (2012), Synthesis and characterization of a multiarm poly(acrylic acid) star polymer for application in sustained delivery of cisplatin and a nitric oxide prodrug. J. Polym. Sci. A Polym. Chem., 50: 2715–2724. doi:10.1002/pola.26059, which has been published in final form at http://doi.org/10.1002/pola.26059. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Functionalized polymeric nanocarriers have been recognized as drug delivery platforms for delivering therapeutic concentrations of chemotherapies. Of this category, star-shaped multiarm polymers are emerging candidates for targeted delivery of anti-cancer drugs, due to their compact structure, narrow size distribution, large surface area and high water solubility. In this study, we synthesized a multi-arm poly(acrylic acid) star polymer via MADIX/RAFT polymerization and characterized it using NMR and size exclusion chromatography. The poly(acrylic acid) star polymer demonstrated excellent water solubility and extremely low viscosity, making it highly suited for targeted drug delivery. Subsequently, we selected a hydrophilic drug, cisplatin, and a hydrophobic nitric oxide-donating prodrug, O2-(2,4-dinitrophenyl) 1-[4-(2-hydroxy)ethyl]-3-methylpiperazin-1-yl]diazen-1-ium-1,2-diolate, as two model compounds to evaluate the feasibility of using poly(acrylic acid) star polymers for delivery of chemotherapeutics. After synthesizing and characterizing two poly(acrylic acid) star polymer-based nanoconjugates, poly(acrylic acid)-cisplatin (acid-Pt) and poly(acrylic acid)-nitric oxide prodrug (acid-NO), the in vitro drug release kinetics of both acid-Pt and acid-NO were determined at physiological conditions. In summary, we have designed and evaluated a polymeric nanocarrier for sustained-delivery of chemotherapies, either as a single treatment or a combination therapy regimen