Oxygenated polycyclic aromatic hydrocarbon (OPAH) and polycyclic aromatic hydrocarbon (PAH) concentrations in soils with soil properties: A global data setWolfgang Wilcke, Moritz Bigalke, Chong Wei, Yongming Han & Benjamin Musa Bandowe
The hazardous oxygenated polycyclic aromatic hydrocarbons (OPAHs) originate from combustion (primary sources) or post-emission conversion of PAHs (secondary sources). We evaluated the global distribution of up to 15 OPAHs in 195 mineral topsoils from 33 study sites (covering 52°N-47°S, 71°W-118°E), to identify indications of primary or secondary sources of OPAHs. The sums of the (frequently measured 7 and 15) OPAH concentrations correlated with those of the S16EPA-PAHs. The relationship of the S16EPA-PAHs concentrations with the...
Highly Sensitive Fluorescence Response to Inclusion Complex Formation of Berberine Alkaloid with CucurbiturilMónika Megyesi, László Biczók & István Jablonkai
The effect of inclusion complex formation on the fluorescence properties of berberine, a clinically important natural alkaloid, was studied using cucurbituril as macrocyclic host compound. The formation of a very stable 1:1 inclusion complex led to about 500-fold fluorescence intensity enhancement, which facilitated the detection of berberine even below nanomolar concentration. Addition of NaCl caused a significant change in the association constant and the fluorescence characteristics of the complex, whereas the variation of the anion...
Determination of Binding Constants of Hydrogen-Bonded Complexes by ITC, NMR CIS, and NMR Diffusion ExperimentsChristiane Dethlefs, Jens Eckelmann, Hauke Kobarg, Thomas Weyrich, Stefan Brammer, Christian Näther & Ulrich Lüning
Abstract The host–guest complex formation between barbital and various acylaminopyridyl isophthalamides (Hamilton receptors) has been determined quantitatively. The syntheses of nine isophthalamide...
The aim of the microseismic Kandel-Elztal experiment (MiKaEl-Ex) is to continuously record the micro-earthquakes with a highly sensitive measuring network. From this measurement data, the micro-earthquake signals will then be identified from the background noise using innovative methods based on artificial intelligence. Then the arrival time of the earthquakes waves are used to calculate the exact location of their sources in the interior of the earth. In this way, potential active faults are found and...
Electrostatic interactions contribute to the control of intramolecular thiol–disulfide isomerization in a proteinTomáš Kubař, Denis Maag, Marina Putzu, Claudia L. Goméz-Flores, Frauke Gräter & Marcus Elstner
The role of structural factors and of electrostatic interactions with the environment on the outcome of thiol–disulfide exchange reactions were investigated in a mutated immunoglobulin domain (I27*) under mechanical stress. An extensive ensemble of molecular dynamics trajectories was generated by means of QM/MM simulations for a total sampling of 5.7 μs. A significant number of thiol–disulfide exchanges were observed, and the Cys32 thiolate preferred to attack Cys55 over Cys24, in agreement with previous experimental and...
Understanding the physical processes that control the behavior of subduction zone megathrust faults remains one of the outstanding challenges in Earth sciences. These faults generate the largest earthquakes and giant tsunami (e.g. Mw 9.5 Chile 1960, Mw 9.2 Alaska 1964, Sumatra 2004 Mw 9.1, Mw 9.0 Tohoku 2011). Furthermore, deformation along megathrust faults is ultimately responsible for mountain building processes which generate the longest and tallest mountain ranges on Earth and therefore shaping Earth surface...
One key event in insect evolution was the development of mandibles with two joints, which allowed powerful biting, but restricted their movement to a single degree of freedom. These mandibles define the Dicondylia, which constitute over 99 percent of all extant insect species. It was common doctrine that the dicondylic articulation of chewing mandibles remained unaltered for more than 400 million years. We report highly modified mandibles overcoming the restrictions of a single degree of...
Rational design and implementation of a cucurbituril-based indicator-displacement assay for application in blood serumFrank Biedermann, Stephan Sinn, Eduard Spuling & Stefan Braese
In this study, we report the first supramolecular indicator displacement assay (IDA) based on cucurbit[n]uril (CBn) host and a [2.2]paracyclophane derivative as indicator that is operational in blood serum.
Three borehole sensors (approx. 5 m depth, Trillium Compact 20s) installed in the vicinity of two research wind turbines at the WINSENT test field near Stötten, Baden-Württemberg, Germany.
Reinvestigation of Calixarene-Based Artificial-Signaling Acetylcholine Receptors Useful in Neutral Aqueous (Water/Methanol) SolutionKwang Nak Koh, Koji Araki, Atsushi Ikeda, Hideyuki Otsuka & Seiji Shinkai
It was shown that an artificial acetylcholine (neurotransmitter) detection system using resorcinarene (1: Inouye et al. J. Am. Chem. Soc. 1994, 116, 5517) has substantial problems: both acetylcholine and a fluorescent receptor molecule decompose in 0.01 M KOH/MeOH solution. In their system the strong alkaline medium was necessitated to dissociate OH groups in 1 and to enhance the fluorescence quenching ability. To solve this problem we exploited a new artificial acetylcholine detection system using water-soluble...
The Anatomy of the Energetics of Molecular Recognition by Calorimetry: Chiral Discrimination of Camphor by α-CyclodextrinFranz P. Schmidtchen
Abstract The molecular recognition of both camphor enantiomers 2 with the chiral α-cyclodextrin (α-CD) 1 in water and D2O was examined by calorimetry. On the basis of statistically supported determ...
Cucurbituril host−guest complexations of steroidal neuromuscular blocking agents in aqueous solutionMona A. Gamal-Eldin & Donal H. Macartney
The complexations of three steroidal neuromuscular blocking agents, rocuronium, vecuronium, and pancuronium, by the cucurbituril host molecule have been investigated in aqueous solution using 1H NMR spectroscopy and ESI mass spectrometry. The CB binds to each of the two terminal cationic N-heterocyclic groups by means of ion-dipole interactions and hydrophobic effects, with stability constants in the order of vecuronium > pancuronium > rocuronium. This trend is different from those observed for the anionic substituted γ-cyclodextrin...
We determined the values of Ka for a wide range of host−guest complexes of cucurbit[n]uril (CB[n]), where n = 6−8, using 1H NMR competition experiments referenced to absolute binding constants measured by UV/vis titration. We find that the larger homologuesCB and CBindividually maintain the size, shape, and functional group selectivity that typifies the recognition behavior of CB. The cavity of CB is found to effectively host trimethylsilyl groups. Remarkably, the values of Ka for the...
Teaching old indicators even more tricks: binding affinity measurements with the guest-displacement assay (GDA)Stephan Sinn, Joana Krämer & Frank Biedermann
A simple change has important consequences: the guest-displacement assay (GDA) is introduced which allows for binding affinity determinations of supramolecular complexes with spectroscopically silent hosts and guests.
Cucurbit[n]urils (CBn, n = 7, 8) serve as artificial receptors for steroids (21 tested), including the hormones testosterone and estradiol as well as steroidal drugs. Fluorescence displacement titrations and isothermal titration calorimetry (ITC) provided up to nanomolar binding affinities in aqueous solution for these hydrophobic target molecules, exceeding the values of known synthetic receptors. Remarkable binding selectivities, even for homologous steroid pairs, were investigated in detail by NMR, X-ray crystal diffraction, ITC, and quantum chemical...
Karlsruhe Institute of Technology12
Institute of Nanotechnology3
Karlsruhe Institute of Technology (KIT GPI Germany)3
Département Alimentation Humaine1
Institute of Materials and Environmental Chemistry1
Institute of Organic Chemistry1
University of New Hampshire1
Department of Physical and Technical Sciences1
Shanghai Advanced Research Institute1