Project scheduling under uncertainty and resource constraints

This paper proposes a method to improve the reliability of construction schedules by optimizing schedule robustness of construction projects. The schedule robustness is measured by a criterion evaluating the impact of deviations from the initial schedule on the makespan, which arise during the realization phase of a construction project. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Evaluation of tip-enhanced Raman spectroscopy for characterizing different virus strains

Tip-enhanced Raman spectroscopy (TERS) is a highly sensitive spectroscopic technique which combines the advantages of optical spectroscopy with the requirements needed for the characterization of biological nano-structures. In this study, TERS was used to investigate the applicability of this spectroscopic technique for the detection of different virus strains like avipoxvirus and adeno-associated virus. TERS spectra obtained from different particles of the same virus strain show variations in relative peak intensities and positions of most spectral features observed. These spectral variations were higher for the larger avipoxvirus particles (?≈350 nm) than for the smaller adeno-associated virus particles (?≈26 nm).     

Fast characterization of functionalized silica materials by silicon-29 surface-enhanced NMR spectroscopy using dynamic nuclear polarization

We demonstrate fast characterization of the distribution of surface bonding modes and interactions in a series of functionalized materials via surface-enhanced nuclear magnetic resonance spectroscopy using dynamic nuclear polarization (DNP). Surface-enhanced silicon-29 DNP NMR spectra were obtained by using incipient wetness impregnation of the sample with a solution containing a polarizing radical (TOTAPOL). We identify and compare the bonding topology of functional groups in materials obtained via a sol-gel process and in materials prepared by post-grafting reactions. Furthermore, the remarkable gain in time provided by surface-enhanced silicon-29 DNP NMR spectroscopy (typically on the order of a factor 400) allows the facile acquisition of two-dimensional correlation spectra.     

Affinity of Cu+ for the copper-binding domain of the amyloid-β peptide of Alzheimer's disease

The role of metal ions in Alzheimer's disease etiology is unresolved. For the redox-active metal ions iron and copper, the formation of reactive oxygen species by metal amyloid complexes has been proposed to contribute to Alzheimer's disease neurodegeneration. For copper, reactive oxygen species are generated by copper redox cycling between its 1+ and 2+ oxidation states. Thus, the AβCu(I) complex is potentially a critical reactant associated with Alzheimer's disease etiology. Through competitive chelation, we have measured the affinity of the soluble copper-binding domain of the amyloid-β peptide for Cu(I). The dissociation constants are in the femtomolar range for both wild-type and histidine-to-alanine mutants. These results indicate that Cu(I) binds more tightly to monomeric amyloid-β than Cu(II) does, which leads us to propose that Cu(I) is a relevant in vivo oxidation state.     

RbCN3H4: the first structurally characterized salt of a new class of guanidinate compounds

Rubidium guanidinate, RbCN(3)H(4), was synthesized from guanidine and rubidium hydride, and the crystal structure was determined from powder X-ray diffraction (PXRD) data. RbCN(3)H(4) crystallizes in the orthorhombic space group Pnma (No. 62) with four formula units per cell. The guanidinate anions are arranged in double chains running along the b axis, stacked almost perpendicularly to each other to form a three-dimensional network. The rubidium cations, coordinated by 11 N atoms, occupy the vacancies of the network in a zigzag motif along the b axis. Because the PXRD structure of the CN(3) core clearly indicates the N-atom functionalities and the location of the H-atom positions, the latter spatial parameters were determined from Perdew-Burke-Ernzerhof generalized gradient approximation (GGA-PBE) density functional theory calculations. The corresponding ν(NH) stretching modes can be observed in the IR spectrum, and the volume chemistry of RbCN(3)H(4) mirrors the efficient packing of the saltlike phase.     

LC-MS based quantification of 2'-ribosylated nucleosides Ar(p) and Gr(p) in tRNA

RNA nucleosides are often naturally modified into complex non-canonical structures with key biological functions. Here we report LC-MS quantification of the Ar(p) and Gr(p) 2'-ribosylated nucleosides in tRNA using deuterium labelled standards, and the first detection of Gr(p) in complex fungi.     

H atom adsorption and diffusion on Si(110)-(1×1) and (2×1) surfaces

We present a periodic density-functional study of hydrogen adsorption and diffusion on the Si(110)-(1×1) and (2×1) surfaces, and identify a local reconstruction that stabilizes the clean Si(110)-(1×1) by 0.51 eV. Hydrogen saturates the dangling bonds of surface Si atoms on both reconstructions and the different structures can be identified from their simulated scanning tunneling microscopy/current image tunneling spectroscopy (STM/CITS) images. Hydrogen diffusion on both reconstructions will proceed preferentially along zigzag rows, in between two adjacent rows. The mobility of the hydrogen atom is higher on the (2×1) reconstruction. Diffusion of a hydrogen vacancy on a monohydride Si(110) surface will proceed along one zigzag row and is slightly more difficult (0.2 eV and 0.6 eV on (1×1) and (2×1), respectively) than hydrogen atom diffusion on the clean surface.     

Intuition and exponential growth: bias and the roles of parameterization and complexity

Mathematische Semesterberichte - Exponential growth bias is the phenomenon that humans intuitively underestimate exponential growth. This article reports on an experiment where treatments differ in...     

Synthesis of tribenzyl D-gluco- and D-galactopyranosides

The synthesis of ethyl-3,4,6-tri-O-benzyl-D -glucopyranoside and of ethyl-3,4,6-tri-O-benzyl-D -galactopyranoside is described. These compounds are isomers of ethyl-3,5,6-tri-O-benzyl-D -glucofuranoside, GLYVENOL ®, a substance displaying interesting pharmacological actions.