Studies on Rye Starch Properties and Modification. Part II: Swelling and Solubility Behaviour of Rye Starch Granules

Rye starch shows the typical inhibited swelling behaviour of triticeae starches with an onset of swelling at rather low temperature (50–55°C). Swollen rye starch granules exist as individuals even after swelling at 100°C. The total dispersion of rye starch needs temperatures above 120°C with pressure cooking. On heating of the rye starch suspension preferentially amylose is leached. Defatting of rye starch exhibits no influence on swelling power but results in higher solubility and in increased amylose leaching. The drying procedures applied here resulted in stronger assoziation of the polymer molecules in the starch granule leading to higher swelling temperatures and a reduced solubility. Shiftings of the crystalline/ amorphous-ratio of the starch granules as caused by different drying procedures, had no influence on the results of swelling power investigation but the highest swelling enthalpy as well as Brabender viscosity were exhibited by a sample dried at room temperature. It is proved to be possible to change the swelling behaviour of rye starch to “potato starch type” by slight chemical modification like succination.     

Investigating Alkylated Prodigiosenes and Their Cu(II)-Dependent Biological Activity: Interactions with DNA,Antimicrobial and Photoinduced Anticancer Activity

Prodigiosenes are a family of red pigments with versatile biological activity. Their tripyrrolic core structure has been modified many times in order to manipulate the spectrum of activity. We have been looking systematically at prodigiosenes substituted at the C ring with alkyl chains of different lengths, in order to assess the relevance of this substituent in a context that has not been investigated before for these derivatives: Cu(II) complexation, DNA binding, self-activated DNA cleavage, photoinduced cytotoxicity and antimicrobial activity. Our results indicate that the hydrophobic substituent has a clear influence on the different aspects of their biological activity. The cytotoxicity study of the Cu(II) complexes of these prodigiosenes shows that they exhibit a strong cytotoxic effect towards the tested tumor cell lines. The Cu(II) complex of a prodigiosene lacking any alkyl chain excelled in its photoinduced anticancer activity, thus demonstrating the potential of prodigiosenes and their metal complexes for an application in photodynamic therapy (PDT). Two derivatives along with their Cu(II) complexes showed also antimicrobial activity against Staphylococcus aureus strains.     

Novel color image steganalysis method based on RGB channel empirical modes to expose stego images with diverse payloads

Pattern Analysis and Applications - With the rapid development of technology in the modern digital world, covert communication of secret information as a payload without instigating visible...     

Impact of Peptide Sequences on Their Structure and Function: Mimicking of Virus-Like Nanoparticles for Nucleic Acid Delivery

We rationally designed a series of amphiphilic hepta-peptides enriched with a chemically conjugated guanidiniocarbonylpyrrole (GCP) unit at the lysine side chain. All peptides are composed of polar (GCP) and non-polar (cyclohexyl alanine) residues but differ in their sequence periodicity, resulting in different secondary as well as supramolecular structures. CD spectra revealed the assembly of β-sheet-, α-helical and random structures for peptides 1 , 2 and 3 , respectively. Consequently, this enabled the formation of distinct supramolecular assemblies such as fibres, nanorod-like or spherical aggregates. Notably, all three cationic peptides are equipped with the anion-binding GCP unit and thus possess a nucleic acid-binding centre. However, only the helical ( 2 ) and the unstructured ( 3 ) peptide were able to assemble into small virus-like DNA-polyplexes and effectively deliver DNA into cells. Notably, as both peptides ( 2 and 3 ) were also capable of siRNA-delivery, they could be utilized to downregulate expression of the caner-relevant protein Survivin.     

Coupling Ferroelectric to colloidal Nanocrystals as a Generic Strategy to Engineer the Carrier Density Landscape

The design of infrared nanocrystals-based (NCs) photodiodes faces a major challenge related to the identification of barriers with a well-suited band alignment or strategy to finely control the carrier density. Here, this study explores a general complementary approach where the carrier density control is achieved by coupling an NC layer to a ferroelectric material. The up-and-down change in ferroelectric polarization directly impacts the NC electronic structure, resulting in the formation of a lateral pn junction. This effect is uncovered directly using nano X-ray photoemission spectroscopy, which shows a relative energy shift of 115 meV of the NC photoemission signal over the two different up- and down-polarized ferroelectric regions, a shift as large as the open circuit value obtained in the diode stack. The performance of this pn junction reveals enhanced responsivity and reduced noise that lead to a factor 40 increase in the detectivity value.