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Using molecular dynamics computer simulations we investigate structural and dynamic (diffusion) properties of charged colloidal suspension confined to narrow slit pores with structureless, uncharged walls. The system is modeled on an effective level involving only the macroions, which interact via a combination of a soft-sphere and a screened Coulomb potential. The aim of our study is to identify the role of the range of the macroion-macroion interaction controlled by the inverse Debye screening length, κ. We also compare to bulk properties at the same chemical potential as determined in parallel grand canonical Monte Carlo simulations. Our results reveal a significant influence of the interaction range which competes, however, with the influence of density. At liquidlike densities a decrease of range yields a decreasing mobility (and a corresponding enhancement of local structure) in the bulk system, whereas the reverse effect occurs in narrow slits with thickness of a few particle diameter. These differences can be traced back to the confinement-induced, and κ-dependent, reduction of overall density compared to the bulk reservoir. We also show that an increase of κ softens the oscillations in the normal pressure as function of the wall separation, which is consistent with experimental observations concerning the influence of addition of salt. [ABSTRACT FROM AUTHOR]

Vast amounts of medical information are still recorded as unstructured text. The knowledge contained in this textual data has a great potential to improve clinical routine care, to support clinical research, and to advance personalization of medicine. To access this knowledge, the underlying data has to be semantically integrated – an essential prerequisite to which is information extraction from clinical documents. A body of work, and a good selection of openly available tools for information extraction and semantic integration in the medical domain exist, yet almost exclusively for English language documents. For German texts the situation is rather different: research work is sparse, tools are proprietary or unpublished, and rarely any freely available textual resources exist. In this survey, we (1) describe the challenges of information extraction from German medical documents and the hurdles posed to research in this area, (2) especially address the problems of missing German language resources and privacy implications, and (3) identify the steps necessary to overcome these hurdles and fuel research in semantic integration of textual clinical data. [ABSTRACT FROM AUTHOR]

The 4-amino­pyridinium isonicotinate salt was isolated as a monohydrate, C5H7N ·C6H4NO ·H2O, with a layered cation–water–anion structure. Hydrogen-bonding between layers utilizes all hydrogen-bonding donors and acceptors, whilst π stacking dominates interactions within the organic layers. [ABSTRACT FROM AUTHOR]

Alzheimer's disease is associated with the precipitation of the amyloid β (Aβ) (1-40) peptide in the form of fibrils. Among the full length peptide, smaller fragments such as Aβ (25-35) which retains the toxicity of the full length peptide are also present. Aβ's toxicity is attributed to soluble oligomers which, however, are difficult to study experimentally due to their transient nature. Here we present replica exchange molecular dynamics simulations of Aβ (25-35) dimers in explicit water. Similar to a previous study, dimers are found to exist as disordered compact in equilibrium with ordered extended fibril-like conformations. In addition, our results suggest effects from slight differences in ionic conditions and yield insights on this system in unprecedented detail. In the compact state, the peptides adopt β-hairpin or unstructured U-shaped conformations with different relative orientations. In the extended state, the peptides are outstretched and form antiparallel in- or out-of-register intermolecular β-sheets. In addition to the previous study, we reveal the driving forces governing the equilibrium between the disordered and the fibril-like state. In particular, it is shown that the compact state is favored by a high entropy while the fibril-like state is lower in energy arising from favorable covalent and electrostatic interactions between and within the peptides. Our results suggest that the transition from the compact to the fibril-like state involves reptation, i.e., a change in register of an intermolecular β-sheet without dissociation of the peptides.