Article
Chemistry, Physical
Qiqi Sun, Zheren Chi, Xing Qin, Limei Qin, Yongsheng Li, Dechao Niu
Summary: This study proposes a stepwise-confined self-reduction strategy to construct a dynamic self-reduction dual-metal (Cu/Fe) nanocatalyst that can generate reactive oxygen species in an acidic and reductive tumor microenvironment. In vitro and animal experiments demonstrate that this synergistic catalyst can significantly inhibit tumor growth while ensuring the safety of treatment. This work provides a versatile pathway for the precise construction of bioapplicable multimetal-based nanocatalysts for efficient and safe diagnosis and treatment of tumors.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Applied
Abdelkarim Rjiba, Hassan Khoder, Jawhar Jelassi, Sabine Bouguet-Bonnet, Carole Gardiennet, El-Eulmi Bendeif, Axel Gansmueller, Rachida Dorbez-Sridi
Summary: The study compared the water-restricted properties of two mesoporous bioactive glasses prepared by different methods, revealing that the microfluidic MBG had slightly faster water molecule escaping towards the bulk, indicating a better water access to the full porous volume in the microcapsule organization of microfluidic MBG.
MICROPOROUS AND MESOPOROUS MATERIALS
(2021)
Article
Chemistry, Physical
Elisa Steinruecken, Till Wissel, Martin Brodrecht, Hergen Breitzke, Julia Regentin, Gerd Buntkowsky, Michael Vogel
Summary: A variety of amino-acid functionalized silica pores with diameters of about 6 nm were prepared, and the temperature-dependent reorientation dynamics of water in these confinements were studied. The reorientation dynamics of water strongly depends on the chemistry of the inner surfaces, with different surfaces showing rotational correlation times varying by about two orders of magnitude.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Yusei Kobayashi, Noriyoshi Arai, Kenji Yasuoka
Summary: Despite extensive research, the behavior of confined liquids, especially in the mixed/boundary lubrication regime, remains unclear. This is due to difficulties in directly observing the behavior of lubricant molecules under non-equilibrium conditions, high computational costs for molecular simulations, and low signal-to-noise ratios at very low shear rates. In this study, the correlation between structure formation and shear viscosity of octamethylcyclotetrasiloxane confined between two mica surfaces was investigated. The results showed a strong correlation between the degree of molecular orientation and the shear viscosity of the confined liquids.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Vanda Papp, Robert Janovics, Tamas Peter Kertesz, Zoltan Nemes, Tamas Fodor, Istvan Banyai, Monika Keri
Summary: In the hydration process of cement, the interaction between water and cement plays a crucial role in its application. This study investigates the effects of metakaolin and various components of the liquid phase on the structure of hydrated cement using nuclear magnetic resonance methods. The results show that metakaolin can be incorporated into the cement without altering its mesoporous structure, but significantly reduces the size of capillary pores and the diffusion coefficient of water.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Chemistry, Multidisciplinary
Marina V. Solovyeva, Irina V. Krivosheeva, Larisa G. Gordeeva, Alexander E. Khudozhitkov, Daniil I. Kolokolov, Alexander G. Stepanov, Ralf Ludwig
Summary: In this study, novel composite sorbents based on hygroscopic salts loaded in the pores of MIL-101(Cr) were developed for atmospheric water harvesting (AWH) in arid regions. The CaCl2/MIL-101(Cr) composite demonstrated a high net water uptake under extra-dry climate conditions, surpassing other adsorbents. The water adsorption on the composite exhibited a synergistic effect and the pore confinement in MIL-101(Cr) promoted a prolonged transition to a dynamically melted state of the hydrated salt, resulting in altered sorption properties of CaCl2.
Article
Chemistry, Multidisciplinary
Manuel Petroselli, Julius Rebek, Yang Yu
Summary: Reduction of alkyl dihalide guests with trialkylsilanes in water-soluble host 1 showed high selectivity for mono-reduced products, emphasizing the importance of host-guest complexation rates in modulating product selectivity in radical reactions.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Multidisciplinary Sciences
N. Kana, R. Morad, M. Akbari, M. Henini, J. Niemela, F. Hacque, A. Gibaud, M. Maaza
Summary: Experiments show that Hg nanoparticles with a size of less than or equal to 2.4 nm, embedded in a 2D turbostratic Boron Nitride matrix, undergo a net crystallization at room temperature and exhibit solid rhombohedral alpha-phase. The observed crystallization is correlated with the surface atomic ordering of the rhombohedral alpha-phase. This innovative size effect on phase transition phenomena in Hg has potential applications in Hg waste storage technology. Considering the high vapor pressure of bulk Hg, confining solid nano-Hg at room temperature could be a green approach to Hg waste storage derived from modern efficient light technology.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Analytical
Yulia B. Monakhova, Bernd W. K. Diehl
Summary: The paper discusses a new NMR standardization approach using the 2H integral of deuterated solvent for quantitative multinuclear analysis of pharmaceuticals. It extends the existing NMR procedure for the analysis of heparin products to determine Na+ and Cl- content in the matrix. Validation characteristics are evaluated, and the methodology provides an appealing alternative for NMR screening of inorganic and organic components in pharmaceutical products.
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Marie Juramy, Romain Chevre, Paolo Cerreia Vioglio, Fabio Ziarelli, Eric Besson, Stephane Gastaldi, Stephane Viel, Pierre Thureau, Kenneth D. M. Harris, Giulia Mollica
Summary: This study demonstrates the use of dynamic nuclear polarization (DNP) enhanced NMR spectroscopy to investigate crystallization under nanoscopic confinement, successfully observing the early stages of crystallization and intermediate phases. The experimental strategy allows for the direct observation of the transition from the solution phase to the first crystalline phase.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Biochemistry & Molecular Biology
Michael Fardis, Marina Karagianni, Lydia Gkoura, George Papavassiliou
Summary: Confined liquids, especially bulk water, serve as model systems for studying the metastable supercooled state. However, the onset of crystallization below 230 K makes it difficult to apply experimental techniques. Confined water exhibits drastically different properties at the nanoscale due to the nature of the confining environment and the interactions with the confining matrix. This study demonstrates that the translational mobility of water molecules, particularly in the supercooled state, can distinguish between hydrophilic and hydrophobic environments. Nuclear magnetic resonance and quasi-elastic neutron scattering are effective experimental methods for assessing water dynamics.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Engineering, Environmental
Jintao Hu, Hu Zhang, Zheng Li, Suiqiao Yang, Shengrong Zhang, Hongchun Li, Ming Lu
Summary: Warm frozen soil in cold regions is currently being studied by many researchers. Its mechanical properties, especially its dynamic properties, are crucial for the instability of frozen soil foundations. Confined compression tests under dynamic load were conducted to clarify the relationship between the deformation of warm frozen soils and pore-water pressure. The results indicate that the variation of pore-water pressure and deformation characteristics of warm frozen soils under dynamic loading can provide valuable insights for safe work in cold regions.
COLD REGIONS SCIENCE AND TECHNOLOGY
(2023)
Article
Mechanics
Jize Sui
Summary: Unidirectional solvent evaporation is increasingly important in manipulating the self-assembly dynamics of shape anisotropic colloids. We developed a theoretical framework for the growth dynamics of nematic liquid crystals in nanoplatelet suspension confined to a Hele-Shaw channel. Numerical measurements showed that the growth dynamics are correlated with drying rate, nanoplatelet aspect ratio, and geometric confinement. Thick nanoplatelets result in shorter final length of LC, while the average growth velocity depends on the drying rate. Enhanced geometric confinement promotes the growth of LC significantly.
Article
Biochemistry & Molecular Biology
Lydia Gkoura, Nikolaos Panopoulos, Marina Karagianni, George Romanos, Aris Chatzichristos, George Papavassiliou, Jamal Hassan, Michael Fardis
Summary: The molecular dynamics of 1-butyl-3-methyl imidazolium tricyanomethanide ionic liquid confined in SBA-15 mesoporous silica were investigated using H-1 NMR spin-lattice relaxation and diffusion measurements. Results showed that the mobility of the confined cations reduces significantly compared to the bulk in the high-temperature liquid state. The confinement also drives the ionic liquid to the glassy state at a higher temperature than the bulk, and an unusual temperature dependence is observed in the high-temperature regime.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Physical
Wen-Cheng Qiao, Jiaqi Liang, Wei Dong, Kaiyang Ma, Xue Lu Wang, Ye-Feng Yao
Summary: This study used in situ solid-state H-2 nuclear magnetic resonance (NMR) spectroscopy to investigate the rotational dynamics and orientations of MA cations in different phase structures of MAPbBr(3). The results showed a wide distribution of MA cation orientations in MAPbBr(3) and that illumination induces changes in their rotational dynamics while their orientations remain nearly unchanged.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Construction & Building Technology
Annika Lidwina Schultheiss, Ravi A. Patel, Michael Vogel, Frank Dehn
Summary: This study summarizes and compares different modeling approaches for considering cracks and proposes a new method to account for their influence on concrete service life. The research findings demonstrate that the choice of model extension significantly affects prediction results and reveals the limitations of current extensions.
STRUCTURAL CONCRETE
(2023)
Article
Mathematics, Applied
Michael Voit
Summary: This study focuses on the criteria for ensuring positive Gibbs states on distance-regular graphs. The main criterion assumes that the graph can be embedded into a growing family of distance-regular graphs. To prove positivity, polynomial hypergroup theory is used to translate it into an integral representation problem. The criteria are applied to several examples, resulting in a complete description of positive Gibbs states for Hamming graphs and infinite distance-transitive graphs.
INFINITE DIMENSIONAL ANALYSIS QUANTUM PROBABILITY AND RELATED TOPICS
(2023)
Article
Engineering, Electrical & Electronic
Rastislav Ries, Eugen Seiler, Fedor Gomory, Arturs Medvids, Pavels Onufrijevs, Cristian Pira, Eduard Chyhyrynets, Oleg B. Malyshev, Reza Valizadeh, Stewart Leith, Michael Vogel
Summary: In this study, two series of Nb/Cu samples were deposited using the HiPIMS technique with differing Nb deposition conditions, Nb film thickness, and Cu substrate polishing techniques. Nd:YAG laser irradiation was used to smooth the surfaces of all films. The impact of magnetic field enhancement at surface defects on the premature start of magnetic field penetration into the superconducting film was investigated through experiments and numerical calculations. Improved numerical calculations using the Finite Element Method (FEM) were employed to calculate the maximum field enhancement factor beta(m), reflecting the impact of crucial surface defects found in the samples. Magnetization measurements at 4.2K in a DC magnetic field, parallel to the film orientation, were conducted to determine the start of field penetration H-en. SEM and AFM analyses were performed to investigate the Nb surface morphology. Deviations from the H-en (beta(m)) dependence were observed in some samples, and it was found that magnetic field penetration could start from the Nb/Cu interface rather than the free Nb surface due to better surface quality observed by SEM analysis, potentially leading to deterioration of the H-en (beta(m)) dependence.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Chemistry, Physical
Markus M. Hoffmann, Matthew D. Too, Nathaniel A. Paddock, Robin Horstmann, Sebastian Kloth, Michael Vogel, Gerd Buntkowsky
Summary: In this study, molecular dynamics simulations were performed to investigate polyethylene glycol (PEG)200. Force fields for describing ethylene glycol oligomers were tested and adjusted to improve the agreement with experimental properties. The simulations revealed that PEG200 is a random mixture of its ethylene glycol oligomer components.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Construction & Building Technology
Jan P. Hoeffgen, Michael Vogel, Oliver Blask, Frank Dehn
Summary: Considering limited resource availability and construction demands, efficient recirculation of building materials is crucial. Recycling aggregates as partial replacements for gravel and sand in concrete production, especially due to the restricted availability of the latter, is essential. However, the use of crushed concrete fines as aggregates or supplementary cementitious material (SCM) leads to limited concrete performance due to the concentration of porous hydrated cement in the fine particles. Recent findings suggest that by subjecting them to additional thermal processing, the reactivation of hydrated cement can improve the mechanical and durability properties of the concrete, such as carbonation or chloride penetration, when used as SCM. These promising results have led to a funded research project that investigates the impact of thermal-mechanical processing on the performance of crushed concrete sands with different compositions as SCM.
BETON- UND STAHLBETONBAU
(2023)
Article
Chemistry, Physical
Ulyana M. Zavorotnaya, Alexei F. Privalov, Celine Wolter, Michael Vogel, Igor I. Ponomarev, Vitaly V. Sinitsyn
Summary: Proton diffusion in the co-PNIS85/15 membrane was investigated at temperatures ranging from 200 to 363 K and different water contents using H-1 SFG NMR diffusometry. At high hydration values, two different activation modes were observed, with the crossover point occurring at approximately 250-260 K. Above the crossover point, the activation energy was similar to that of bulk water. Below the crossover point, the activation energy was higher. At low hydration values, the activation energies for the high-temperature and low-temperature modes converged.
Article
Chemistry, Physical
Yael Beilinson, Verena Schiller, Julia Regentin, Jorge H. Melillo, Anna Greenbaum, Tatiana Antropova, Silvina Cerveny, Michael Vogel, Yuri Feldman
Summary: The dynamics of water confined in mesoporous materials were studied using a combination of techniques including broadband dielectric spectroscopy, nuclear magnetic resonance, and differential scanning calorimetry. The results show that water confined in MIP samples exhibits a dynamic crossover at around 180 K, while water confined in MAP samples does not show any changes in relaxation behavior. The crossover temperature is found to depend on the hydration level. Below the crossover temperature, water reorientation is isotropic and the dielectric relaxation strength follows a solid-like behavior, while above the crossover temperature, water reorientation is related to long-range diffusion and the dielectric relaxation strength follows a liquid-like behavior. The results are also consistent with a glass transition near 180 K.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Physical
Elisa Steinruecken, Max Weigler, Verena Schiller, Michael Vogel
Summary: By confining water to narrow silica pores, the crystallization process is suppressed. The dynamical susceptibilities of the liquid are determined using broadband dielectric spectroscopy (BDS) and 1H and 2H nuclear magnetic resonance (NMR), specifically through NMR field-cycling relaxometry. Derivative analysis reveals Vogel-Fulcher-Tammann and Arrhenius regimes at different temperature ranges, separated by a broad crossover region. The results suggest a crossover to an interface-affected, noncooperative relaxation involving both rotational and translational motions.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Kristina Raupach, Andreas Bogner, Michael Vogel, Engin Kotan, Frank Dehn
Summary: The nanoindentation technique is widely used for mechanical characterization of thin film microstructures. It can accurately determine the hardness and elastic modulus of different materials. While nanoindentation is commonly used in industries like metal, ceramic, and plastics processing, its application in concrete technology is relatively new. This study focuses on using nanoindentation to analyze the mechanical properties of hardened cement paste and investigates the effects of sample preparation and measurement parameters on the results. The findings assess the suitability of nanoindentation for studying durability-related damage in concrete.
Article
Robotics
Ge Li, Zeqi Jin, Michael Volpp, Fabian Otto, Rudolf Lioutikov, Gerhard Neumann
Summary: Movement Primitives (MPs) are a well-known concept for representing and generating modular trajectories. There are two types of MPs: dynamics-based approaches that generate smooth trajectories, such as Dynamic Movement Primitives (DMPs), and probabilistic approaches that capture higher-order statistics, such as Probabilistic Movement Primitives (ProMPs). However, there is currently no unified MP method that can generate smooth trajectories while capturing higher-order statistics.
IEEE ROBOTICS AND AUTOMATION LETTERS
(2023)
Article
Chemistry, Physical
Verena Schiller, Katharina Knippen, Alois Loidl, Peter Lunkenheimer, Dirk Volkmer, Michael Vogel
Summary: We used H-2 nuclear magnetic resonance (NMR) to investigate the reorientation and diffusion of water in the metal-organic framework MFU-4l. The study revealed that the rotational correlation times follow different relations above and below certain temperatures, with a continuous evolution in between. The NMR results were consistent with previous broadband dielectric spectroscopy (BDS) data on water in a similar framework. The water dynamics at low temperatures did not fully restore ergodicity, suggesting the presence of spatially heterogeneous water properties.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Alexei F. Privalov, Vitaly V. Sinitsyn, Michael Vogel
Summary: We used NMR static field gradient diffusometry to measure the self-diffusion coefficients of protons and oxygens in Nafion 212, and found that oxygen diffusion is faster than proton diffusion at lower hydration levels, possibly due to the presence of a polymer framework.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Construction & Building Technology
Annika Lidwina Schultheiss, Ravi A. Patel, Michael Vogel, Frank Dehn
Summary: This study summarizes and compares various modeling approaches to evaluate the probabilistic service life prediction. The research findings demonstrate that the choice of model extension for cracks significantly influences the prediction results and shows the limitations of current extensions.
STRUCTURAL CONCRETE
(2023)
