Rasterkraftmikroskopie im Vakuum an plasmabehandeltem und metallisiertem Polycarbonat

Atomic force microscopy under UHV conditions on plasma etched and metallised polycarbonate The paper describes different AFM modes of operations (static ?contact”? mode and dynamic mode). The influence of ECR plasma treatment and Almetallisation is shown on polycarbonate. The plasma etching changes the surface morphology in the nm scale. Aluminum that exhibits low adhesion to the polycarbonate could be resolved only by AFM in the dynamic mode of operation.     

Oxidative Folding of Peptides with Cystine‐Knot Architectures: Kinetic Studies and Optimization of Folding Conditions

Bioactive peptides often contain several disulfide bonds that provide the main contribution to conformational rigidity and structural, thermal, or biological stability. Among them, cystine‐knot peptides—commonly named “knottins”—make up a subclass with several thousand natural members. Hence, they are considered promising frameworks for peptide‐based pharmaceuticals. Although cystine‐knot peptides are available through chemical and recombinant synthetic routes, oxidative folding to afford the bioactive isomers still remains a crucial step. We therefore investigated the oxidative folding of ten protease‐inhibiting peptides from two knottin families, as well as that of an HIV entry inhibitor and of aprotinin, under two conventional sets of folding conditions and by a newly developed procedure. Kinetic studies identified folding conditions that resulted in correctly folded miniproteins with high rates of conversion even for highly hydrophobic and aggregation‐prone peptides in concentrated solutions.     

Existence of unmixed solutions of the discrete-time algebraic Riccati equation and a nonstrictly bounded real lemma

The existence of a solution of the discrete-time algebraic Riccati equation is established assuming modulus controllability and positive semidefiniteness on the unit circle of the Popov function. As an application a nonstrictly bounded real lemma is obtained.     

The Meissner-Ochsenfeld effect as a possible tool to control anisotropy of thermal conductivity and pinning strength of type II superconductors

This paper proposes the Meissner-Ochsenfeld effect as a possible tool for quality control of type II superconductors (SC). Visual or optical inspection of the levitation process allows rough determination of the anisotropy of thermal conductivity and of the pinning strength of type II SC material, in a materials quality control. An assembly of permanent (e.g. NdFeB) or electromagnets and a flat cryostat allowing visual or optical inspection would be required. The method is demonstrated by numerically simulating the field cooling process of a superconducting cylindrical pellet and of a coated conductor.     

Consumer acceptance of regular and reduced-sugar yogurt enriched with different types of dietary fiber

Reduction of energy in foods by eliminating sugar, combined with an increase in fiber, frequently results in products with sensory characteristics that cannot be compared with standard counterparts. This study analyzed the response of young educated consumers (n = 704) on standard or reduced-sugar vanilla yogurt enriched with inulin or with inulin combined with a grain mixture, a milled mixture of flakes, or a combination of grains and milled flakes. On a nine-point hedonic scale, mean acceptance was 6.4 and 6.8 for yogurt with 112 g kg^?1 and 160 g kg^?1 sugar, respectively. It was concluded from acceptance data and from results obtained by just-about-right rating that adapting the flavoring concentration might be an appropriate tool to mask sugar reduction. In yogurt with visible fiber, it is mainly the size of incorporated fiber that should be considered in product optimization. In these products, sugar content significantly affects acceptance.     

Optimizing the Kinetics and Thermodynamics of DNA i‐Motif Folding

Under slightly acidic conditions, single cytidine‐rich DNA strands can form four‐stranded structures called i‐motifs. The stability of the i‐motif structure is based on the intercalation of hemiprotonated C–C⁺ base pairs. In addition, the stability of these structures is influenced by pH, temperature, salt concentration, number of cytidines per C‐rich stretch, and length of sequence; it also depends on the nucleotides in the connecting loop regions. Here, we investigated the influence of the loop nucleotides on i‐motif stability, structure, and kinetics of folding, in five structures with the same loop‐size but different adenosine and thymidine residues within the loop. The stabilities of the i‐motif structures were determined by CD melting, and structure and kinetics of folding were studied by static and time‐resolved NMR experiments.     

An investigation of Interface-GMRES(R) for fluid–structure interaction problems with flutter and divergence

The basic subiteration method for solving fluid–structure interaction problems consists of an iterative process in which the fluid and structure subsystems are alternatingly solved, subject to complementary partitions of the interface conditions. The main advantages of the subiteration method are its conceptual simplicity and its modularity. The method has several deficiencies, however, including a lack of robustness and efficiency. To bypass these deficiencies while retaining the main advantages of the method, we recently proposed the Interface-GMRES(R) solution method, which is based on the combination of subiteration with a Newton–Krylov approach, in which the Krylov space is restricted to the interface degrees-of-freedom. In the present work, we investigate the properties of the Interface-GMRES(R) method for two distinct fluid–structure interaction problems with parameter-dependent stability behaviour, viz., the beam problem and the string problem. The results demonstrate the efficiency and robustness of the Interface-GMRES(R) method.