TY - JOUR A1 - Zhou, Suqiong A1 - Pan, Yuanwei A1 - Zhang, Jianguang A1 - Li, Yan A1 - Neumann, Falko A1 - Schwerdtle, Tanja A1 - Li, Wenzhong A1 - Haag, Rainer T1 - Dendritic polyglycerol-conjugated gold nanostars with different densities of functional groups to regulate osteogenesis in human mesenchymal stem cells JF - Nanoscale N2 - Nanomaterials play an important role in mimicking the biochemical and biophysical cues of the extracellular matrix in human mesenchymal stem cells (MSCs). Increasing studies have demonstrated the crucial impact of functional groups on MSCs, while limited research is available on how the functional group's density on nanoparticles regulates MSC behavior. Herein, the effects of dendritic polyglycerol (dPG)-conjugated gold nanostars (GNSs) with different densities of functional groups on the osteogenesis of MSCs are systematically investigated. dPG@GNS nanocomposites have good biocompatibility and the uptake by MSCs is in a functional group density-dependent manner. The osteogenic differentiation of MSCs is promoted by all dPG@GNS nanocomposites, in terms of alkaline phosphatase activity, calcium deposition, and expression of osteogenic protein and genes. Interestingly, the dPGOH@GNSs exhibit a slight upregulation in the expression of osteogenic markers, while the different charged densities of sulfate and amino groups show more efficacy in the promotion of osteogenesis. Meanwhile, the sulfated nanostars dPGS20@GNSs show the highest enhancement. Furthermore, various dPG@GNS nanocomposites exerted their effects by regulating the activation of Yes-associated protein (YAP) to affect osteogenic differentiation. These results indicate that dPG@GNS nanocomposites have functional group density-dependent influence on the osteogenesis of MSCs, which may provide a new insight into regulating stem cell fate. Y1 - 2020 U6 - https://doi.org/10.1039/d0nr06570f SN - 2040-3364 SN - 2040-3372 VL - 12 IS - 47 SP - 24006 EP - 24019 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Radbruch, Moritz A1 - Pischon, Hannah A1 - Ostrowski, Anja A1 - Volz, Pierre A1 - Brodwolf, Robert A1 - Neumann, Falko A1 - Unbehauen, Michael A1 - Kleuser, Burkhard A1 - Haag, Rainer A1 - Ma, Nan A1 - Alexiev, Ulrike A1 - Mundhenk, Lars A1 - Gruber, Achim D. T1 - Dendritic core-multishell nanocarriers in murine models of healthy and atopic skin JF - Nanoscale Research Letters N2 - Dendritic hPG-amid-C18-mPEG core-multishell nanocarriers (CMS) represent a novel class of unimolecular micelles that hold great potential as drug transporters, e. g., to facilitate topical therapy in skin diseases. Atopic dermatitis is among the most common inflammatory skin disorders with complex barrier alterations which may affect the efficacy of topical treatment. Here, we tested the penetration behavior and identified target structures of unloaded CMS after topical administration in healthy mice and in mice with oxazolone-induced atopic dermatitis. We further examined whole body distribution and possible systemic side effects after simulating high dosage dermal penetration by subcutaneous injection. Following topical administration, CMS accumulated in the stratum corneum without penetration into deeper viable epidermal layers. The same was observed in atopic dermatitis mice, indicating that barrier alterations in atopic dermatitis had no influence on the penetration of CMS. Following subcutaneous injection, CMS were deposited in the regional lymph nodes as well as in liver, spleen, lung, and kidney. However, in vitro toxicity tests, clinical data, and morphometry-assisted histopathological analyses yielded no evidence of any toxic or otherwise adverse local or systemic effects of CMS, nor did they affect the severity or course of atopic dermatitis. Taken together, CMS accumulate in the stratum corneum in both healthy and inflammatory skin and appear to be highly biocompatible in the mouse even under conditions of atopic dermatitis and thus could potentially serve to create a depot for anti-inflammatory drugs in the skin. KW - CMS KW - Skin KW - Topical treatment KW - Dermal delivery KW - Atopic dermatitis KW - Oxazolone KW - Fluorescence lifetime imaging microscopy KW - Nanomaterials KW - Multi-domain nanoparticles KW - Penetration enhancement Y1 - 2017 U6 - https://doi.org/10.1186/s11671-017-1835-0 SN - 1556-276X VL - 12 IS - 64 PB - Springer CY - New York ER - TY - JOUR A1 - Becker, Michael A1 - Neumann, Marko A1 - Tetzner, Julia A1 - Böse, Susanne A1 - Knoppick, Henrike A1 - Maaz, Kai A1 - Baumert, Jürgen A1 - Lehmann, Rainer T1 - Development? Effects of the transition into academically selective schools JF - The journal of educational psychology N2 - The present study investigates school context effects on psychosocial characteristics (academic self-concept, peer relations, school satisfaction, and school anxiety) of high-achieving and gifted students. Students who did or did not make an early transition from elementary to secondary schools for high-achieving and gifted students in 5th grade in Berlin, Germany, are compared in their psychosocial development. The sample comprises 155 early-entry students who moved to an academically selective secondary school (Gymnasium) and 3,169 regular students who remained in elementary school until the end of 6th grade. Overall, a complex pattern of psychosocial development emerged for all students, with both positive and negative outcomes being observed. Specifically, the transition into academically selective learning environments seemed to come at some cost for psychosocial development. Propensity score matching analysis isolating the effects of selective school intake and the school context effect itself revealed negative contextual effects of early transition to Gymnasium on academic self-concept and school anxiety; additionally, the positive trend in peer relations observed among regular students was not discernible among early-entry students. KW - psychosocial development KW - transition KW - ability grouping KW - longitudinal design KW - propensity score matching Y1 - 2014 U6 - https://doi.org/10.1037/a0035425 SN - 0022-0663 SN - 1939-2176 VL - 106 IS - 2 SP - 555 EP - 568 PB - American Psychological Association CY - Washington ER - TY - JOUR A1 - Zülicke, Lutz A1 - Ragnetti, Francesca A1 - Neumann, Rainer A1 - Zuhrt, Christian T1 - Ionized Van-der-Waals systems : structure and interactions JF - Technical Report / Institute of Physical and Theoretical Chemistry, Potsdam Y1 - 1996 VL - 1996, 01 PB - Univ. CY - Potsdam ER - TY - JOUR A1 - Li, Junbai A1 - Miller, Reinhard A1 - Wüstneck, Rainer A1 - Möhwald, Helmuth A1 - Neumann, A. W. T1 - News of pendant drop technique as a film balance at liquid/liquid interfaces Y1 - 1995 ER - TY - JOUR A1 - Zülicke, Lutz A1 - Ragnetti, Francesca A1 - Neumann, Rainer T1 - Ionized Van-der-Waals systems : structure and interactions Y1 - 1997 ER - TY - JOUR A1 - Miller, Reinhard A1 - Li, Junbai A1 - Wüstneck, Rainer A1 - Krägel, Jürgen A1 - Clark, David C. A1 - Neumann, Wilhelm A. T1 - Pendant drop technique for studies of dynamic properties of soluble adsorption layers and insoluble monolayers Y1 - 1995 ER - TY - JOUR A1 - Zuhrt, Christian A1 - Neumann, Rainer A1 - Zülicke, Lutz T1 - Investigation of vibrational states of the ArHCl+ cation in the electronic ground state Y1 - 1999 ER - TY - JOUR A1 - Penschke, Christopher A1 - Edler von Zander, Robert A1 - Beqiraj, Alkit A1 - Zehle, Anna A1 - Jahn, Nicolas A1 - Neumann, Rainer A1 - Saalfrank, Peter T1 - Water on porous, nitrogen-containing layered carbon materials BT - the performance of computational model chemistries JF - Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies / RSC, Royal Society of Chemistry N2 - Porous, layered materials containing sp(2)-hybridized carbon and nitrogen atoms, offer through their tunable properties, a versatile route towards tailormade catalysts for electrochemistry and photochemistry. A key molecule interacting with these quasi two-dimensional materials (2DM) is water, and a photo(electro)chemical key reaction catalyzed by them, is water splitting into H-2 and O-2, with the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) as half reactions. The complexity of some C/N-based 2DM in contact with water raises special needs for their theoretical modelling, which in turn is needed for rational design of C/N-based catalysts. In this work, three classes of C/N-containing porous 2DM with varying pore sizes and C/N ratios, namely graphitic carbon nitride (g-C3N4), C2N, and poly(heptazine imides) (PHI), are studied with various computational methods. We elucidate the performance of different models and model chemistries (the combination of electronic structure method and basis set) for water and water fragment adsorption in the low-coverage regime. Further, properties related to the photo(electro)chemical activity like electrochemical overpotentials, band gaps, and optical excitation energies are in our focus. Specifically, periodic models will be tested vs. cluster models, and density functional theory (DFT) vs. wavefunction theory (WFT). This work serves as a basis for a systematic study of trends for the photo(electro)chemical activity of C/N-containing layered materials as a function of water content, pore size and density. Y1 - 2022 U6 - https://doi.org/10.1039/d2cp00657j SN - 1463-9076 SN - 1463-9084 VL - 24 IS - 24 SP - 14709 EP - 14726 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Wirth, Jonas A1 - Neumann, Rainer A1 - Antonietti, Markus A1 - Saalfrank, Peter T1 - Adsorption and photocatalytic splitting of water on graphitic carbon nitride: a combined first principles and semiempirical study JF - Physical chemistry, chemical physics : a journal of European Chemical Societies N2 - Graphitic carbon nitride, g-C3N4, is a promising organic photo-catalyst for a variety of redox reactions. In order to improve its efficiency in a systematic manner, however, a fundamental understanding of the microscopic interaction between catalyst, reactants and products is crucial. Here we present a systematic study of water adsorption on g-C3N4 by means of density functional theory and the density functional based tight-binding method as a prerequisite for understanding photocatalytic water splitting. We then analyze this prototypical redox reaction on the basis of a thermodynamic model providing an estimate of the overpotential for both water oxidation and H+ reduction. While the latter is found to occur readily upon irradiation with visible light, we derive a prohibitive overpotential of 1.56 eV for the water oxidation half reaction, comparing well with the experimental finding that in contrast to H-2 production O-2 evolution is only possible in the presence of oxidation cocatalysts. Y1 - 2014 U6 - https://doi.org/10.1039/c4cp02021a SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 30 SP - 15917 EP - 15926 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Wirth, Jonas A1 - Neumann, Rainer A1 - Antonietti, Markus A1 - Saalfrank, Peter T1 - Adsorption and photocatalytic splitting of water on graphitic carbon nitride BT - a combined first principles and semiempirical study JF - physical chemistry, chemical physics : PCCP N2 - Graphitic carbon nitride, g-C₃N₄, is a promising organic photo-catalyst for a variety of redox reactions. In order to improve its efficiency in a systematic manner, however, a fundamental understanding of the microscopic interaction between catalyst, reactants and products is crucial. Here we present a systematic study of water adsorption on g-C₃N₄ by means of density functional theory and the density functional based tight-binding method as a prerequisite for understanding photocatalytic water splitting. We then analyze this prototypical redox reaction on the basis of a thermodynamic model providing an estimate of the overpotential for both water oxidation and H⁺ reduction. While the latter is found to occur readily upon irradiation with visible light, we derive a prohibitive overpotential of 1.56 eV for the water oxidation half reaction, comparing well with the experimental finding that in contrast to H₂ production O₂ evolution is only possible in the presence of oxidation cocatalysts. KW - initio molecular-dynamics KW - augmented-wave method KW - visible-light KW - tight-binding KW - transition KW - oxidation KW - photooxidation KW - simulations KW - reduction KW - hydrogen Y1 - 2014 U6 - https://doi.org/10.1039/c4cp02021a SN - 1463-9076 SN - 1463-9084 VL - 2014 IS - 16 SP - 15917 EP - 15926 ER -