Inst. Chemie

874 Items

Recent Submissions
Structural Analysis of a Modern o/w-Emulsion Stabilized by a Polyglycerol Ester Emulsifier and Consistency Enhancers

Dahl, Verena ; Friedrich, Achim ; Meyer, Jürgen ; Venzmer, Joachim ; Belkoura, Lhoussaine ; Strey, Reinhard ; Mayer, Christian ; Michel, Raphael ; Gradzielski, Michael (2018-01-18)

The aim of our work was to study the structure of a typical modern cosmetic oil-in-water emulsion (o/w-emulsion), based on the emulsifier polyglyceryl-3 dicitrate/stearate and glycerylstearate/stearyl alcohol as consistency enhancer. We have used a systematic approach building up the cosmetic emulsion step by step, characterizing all systems by using Small Angle Neutron Scattering (SANS), Diffe...

The Natural Fungal Metabolite Beauvericin Exerts Anticancer Activity In Vivo: A Pre-Clinical Pilot Study

Heilos, Daniela ; Rodríguez-Carrasco, Yelko ; Englinger, Bernhard ; Timelthaler, Gerald ; Van Schoonhoven, Sushilla ; Sulyok, Michael ; Boecker, Simon ; Süßmuth, Roderich D. ; Heffeter, Petra ; Lemmens-Gruber, Rosa ; Dornetshuber-Fleiss, Rita ; Berger, Walter (2017-08-24)

Recently, in vitro anti-cancer properties of beauvericin, a fungal metabolite were shown in various cancer cell lines. In this study, we assessed the specificity of this effect by comparing beauvericin cytotoxicity in malignant versus non-malignant cells. Moreover, we tested in vivo anticancer effects of beauvericin by treating BALB/c and CB-17/SCID mice bearing murine CT-26 or human KB-3-1-gra...

Optimisation of Surface-Initiated Photoiniferter-Mediated Polymerisation under Confinement, and the Formation of Block Copolymers in Mesoporous Films

Tom, Jessica ; Brilmayer, Robert ; Schmidt, Johannes ; Andrieu-Brunsen, Annette (2017-10-23)

Nature as the ultimate inspiration can direct, gate, and selectively transport species across channels to fulfil a specific targeted function. Harnessing such precision over local structure and functionality at the nanoscale is expected to lead to indispensable developments in synthetic channels for application in catalysis, filtration and sensing, and in drug delivery. By combining mesoporous ...

Nanoparticle Enhanced Antibody and DNA Biosensors for Sensitive Detection of Salmonella

Savas, Sumeyra ; Ersoy, Aylin ; Gulmez, Yakup ; Kilic, Selcuk ; Levent, Belkis ; Altintas, Zeynep (2018-08-27)

Bacteria-related pathogenic diseases are one of the major health problems throughout the world. Salmonella is a genus of rod-shaped Gram-negative enterobacteria of which more than 2600 serotypes have been identified. Infection with Salmonella can cause salmonellosis, a serious bacterial toxi-infection syndrome associated with gastroenteritis, and paralyphoid and typhoid fevers. Its rapid and se...

Structural complexities and sodium-ion diffusion in the intercalates NaxTiS2: move it, change it, re-diffract it

Wiedemann, Dennis ; Suard, Emmanuelle ; Lerch, Martin (2019-09-03)

After momentary attention as potential battery materials during the 1980s, sodium titanium disulphides, like the whole Na–Ti–S system, have only been investigated in a slapdash fashion. While they pop up in current reviews on the very subject time and again, little is known about their actual crystal-structural features and sodium-ion diffusion within them. Herein, we present a short summary of...

Nanomechanics and Nanorheology of Microgels at Interfaces

Backes, Sebastian ; Klitzing, Regine von (2018-09-03)

The review addresses nanomechanics and nanorheology of stimuli responsive microgels adsorbed at an interface. In order to measure the mechanical properties on a local scale, an atomic force microscope is used. The tip presents an indenter with a radius of curvature of a few 10 s of nm. Static indentation experiments and dynamic studies with an excited cantilever are presented. The effect of sev...

Spatial Frequency Response of Epoxy-Based Volume Holographic Recording Material

Sabel, Tina (2019-03-14)

Holographic volume phase gratings are recorded in an epoxy-based, free-surface, volume holographic recording material. Light-induced gratings are formed by photo-triggered mass migration caused by component diffusion. The material resolution enables a wide range of pattern spacings, to record both transmission and reflection holograms with many different spatial frequencies. An optimum spatial ...

Axial-chirale Bor- und Phosphor-Lewis-Säuren als Katalysatoren in der Carbonylhydrosilylierung und Nazarov-Cyclisierung

Süsse, Lars (2019)

Die vorliegende Dissertation widmet sich der Synthese und Charakterisierung axial-chiraler Bor- und Phosphor-Lewis-Säuren und deren Anwendung in der enantioselektiven Katalyse. Der erste Teil der Arbeit umfasst die Darstellung eines mono-C6F5-substituierten Borans mit Phenylgruppen in den 3,3'-Positionen eines Binaphthylrückgrats. Während die Trennung des freien Borans vom Stannannebenprodukt ...

An Assessment of the Bioactivity of Coffee Silverskin Melanoidins

Tores de la Cruz, Silvia ; Iriondo-DeHond, Amaia ; Herrera, Teresa ; Lopez-Tofiño, Yolanda ; Galvez-Robleño, Carlos ; Prodanov, Marin ; Vélazquez Escobar, Francisco ; Abalo, Raquel ; del Castillo, Maria Dolores (2019-02-12)

Melanoidins present in coffee silverskin, the only by-product of the roasting process, are formed via the Maillard reaction. The exact structure, biological properties, and mechanism of action of coffee silverskin melanoidins, remain unknown. This research work aimed to contribute to this novel knowledge. To achieve this goal, melanoidins were obtained from an aqueous extract of Arabica coffee ...

Graphene Quantum Dots as Nanozymes for Electrochemical Sensing of Yersinia enterocolitica in Milk and Human Serum

Savas, Sumeyra ; Altintas, Zeynep (2019-07-08)

The genus Yersinia contains three well-recognized human pathogens, including Y. enterocolitica, Y. pestis, and Y. pseudotuberculosis. Various domesticated and wild animals carry Yersinia in their intestines. Spread to individuals arises from eating food or water contaminated by infected human or animal faeces. Interaction with infected pets and domestic stock may also lead to infection. Yersini...

Computation of NMR shifts for paramagnetic solids

Mondal, Arobendo (2018)

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for studying the structural and electronic properties of paramagnetic solids such as battery materials, metal-organic frameworks, and molecular/ionic crystals. However, the interpretation of paramagnetic NMR spectra is often challenging as a result of the interactions of unpaired electrons with the nuclear spins of interest. In th...

Weak Values and Two-State Vector Formalism in Elementary Scattering and Reflectivity—A New Effect

Chatzidimitriou-Dreismann, Chariton Aris (2019-02-12)

The notions of Weak Value (WV) and Two-State Vector Formalism (TSVF), firstly introduced by Aharonov and collaborators, provide a quantum-theoretical formalism of extracting new information from a system in the limit of small disturbances to its state. Here, we explore two applications to the case of non-relativistic two-body scattering with one body weakly interacting with its environment. We ...

Gels Obtained by Colloidal Self-Assembly of Amphiphilic Molecules

Malo de Molina, Paula ; Gradzielski, Michael (2017-08-03)

Gelation in water-based systems can be achieved in many different ways. This review focusses on ways that are based on self-assembly, i.e., a bottom-up approach. Self-assembly naturally requires amphiphilic molecules and accordingly the systems described here are based on surfactants and to some extent also on amphiphilic copolymers. In this review we are interested in cases of low and moderate...

Relations between Structure, Activity and Stability in C3N4 Based Photocatalysts Used for Solar Hydrogen Production

Sivasankaran, Ramesh P. ; Rockstroh, Nils ; Hollmann, Dirk ; Kreyenschulte, Carsten R. ; Agostini, Giovanni ; Lund, Henrik ; Acharjya, Amitava ; Rabeah, Jabor ; Bentrup, Ursula ; Junge, Henrik ; Thomas, Arne ; Brückner, Angelika (2018-01-29)

Solar hydrogen production from water could be a sustainable and environmentally friendly alternative to fossil energy carriers, yet so far photocatalysts active and stable enough for large-scale applications are not available, calling for advanced research efforts. In this work, H2 evolution rates of up to 1968 and 5188 μmol h−1 g−1 were obtained from aqueous solutions of triethanolamine (TEOA)...

Inner structure and dynamics of microgels with low and medium crosslinker content prepared via surfactant-free precipitation polymerization and continuous monomer feeding approach

Kyrey, Tetyana ; Witte, Judith ; Feoktystov, Artem ; Pipich, Vitaliy ; Wu, Baohu ; Pasini, Stefano ; Radulescu, Aurel ; Witt, Marcus U. ; Kruteva, Margarita ; Klitzing, Regine von ; Wellert, Stefan ; Holderer, Olaf (2019-07-17)

The preparation of poly(N-isopropylacrylamide) microgels via classical precipitation polymerization (batch method) and a continuous monomer feeding approach (feeding method) leads to different internal crosslinker distributions, i.e., from core–shell-like to a more homogeneous one. The internal structure and dynamics of these microgels with low and medium crosslinker concentrations are studied ...

Experimental Activity Descriptors for Iridium-based Catalysts for the Electrochemical Oxygen Evolution Reaction (OER)

Spöri, Camillo Wolfgang ; Briois, Pascal ; Nong, Hong Nhan ; Reier, Tobias ; Billard, Alain ; Kühl, Stefanie ; Teschner, Detre ; Strasser, Peter (2019-06-13)

Recent progress in the activity improvement of anode catalysts for acidic electrochemical water splitting was largely achieved through empirical studies of iridium-based bimetallic oxides. However, practical, experimentally accessible, yet general predictors of catalytic OER activity are lacking. This study investigates iridium and iridium-nickel thin film model electrocatalysts for the OER and...

The Stability Challenges of Oxygen Evolving Catalysts: Towards a Common Fundamental Understanding and Mitigation of Catalyst Degradation

Spöri, Camillo Wolfgang ; Kwan, Jason Tai Hong ; Bonakdarpour, Arman ; Wilkinson, David P. ; Strasser, Peter (2017-05-04)

This review addresses the technical challenges, their scientific basis, as well as recent progress and the road ahead with respect to the stability and degradation of OER catalysts operating at electrolyzer anodes in acidic environments with an emphasis on MEA based operation. First, we start clarifying the complexity associated with the term “catalyst stability”, cover today’s performance targ...

Kinetic study of dry reforming of Methane with Ni over different supports and Pt/Al2O3

Guan, Chengyue (2019)

This thesis presents a kinetic study on Ni series catalysts for dry reforming of methane (DRM) and comparison with a commercially noble metal catalyst Pt/Al2O3. For each catalyst, a corresponding kinetic model needs to be established. These kinetic schemes should be sophisticated enough to describe the consumption rates, meanwhile rather simple for industrial applications. In this thesis, we in...

Direct utilization of methane: from mechanism understanding to process optimization

Parishan, Samira (2019)

Methane, which is a promising alternative to replace crude oil, is currently underutilized. Industrialization of either OCM or DMTM could realize utilization of methane to value-added chemicals. But, unfortunately, none of these reactions have still an industrially acceptable yield. In this thesis, it was searched for the solutions to overcome these yield barriers. The focus in the OCM projec...

Structural Dynamics of Spin Crossover in Iron(II) Complexes with Extended-Tripod Ligands

Stock, Philipp ; Wiedemann, Dennis ; Petzold, Holm ; Hörner, Gerald (2017-09-05)

Selective manipulation of spin states in iron(II) complexes by thermal or photonic energy is a desirable goal in the context of developing molecular functional materials. As dynamic spin-state equilibration in isolated iron(II) complexes typically limits the lifetime of a given spin state to nanoseconds, synthetic strategies need to be developed that aim at inhibited relaxation. Herein we show ...