Grauhörnchen vs. Eichhörnchen

Competition for resources in Europe's forests – grey versus red squirrels As a result of the introduction of the north American grey squirrel in Britain, Ireland and Italy in the 19th and 20th century, the sole native tree squirrel species in Europe – the red squirrel – faced a completely novel competitor. In order to understand the interactions between the two species and to develop a conservation strategy, the two species' biology and ecology was the focus of intense research over the last 25 years. We provide an overview of research findings and the complex competitive interactions for resources and the curcial role of disease in the replacement of native red by introduced grey squirrels. Key factors in the competitive replacement process are habitat composition and patterns of seed food availability, which directly influence individual body condition and reproductive success. In addition, in the British Isles a squirrelpox virus for which grey squirrels act as a reservoir and vector has a drastic impact on the competitive interactions between the two species.     

Die Mundhöhle als Ökosystem

Biomimetic approaches for the dental plaque control Tooth and gum diseases are widespread and are primarily based on the presence of bacterial biofilms. The characterization of biofilms can be carried out by means of state‐of‐the‐art microbiome analysis that can provide information on bacterial composition and diversity. Modern oral care products mostly contain different antimicrobial agents for biofilm control. These include chlorhexidine, metal salts, and quaternary ammonium compounds, which, however, often kill harmful (dysbiotic) and useful bacteria (homeostatic) (unspecific antimicrobial effect). Recent developments show that innovative concepts shift the ecological balance of plaque in the oral cavity to “physiological commensal bacteria” (homeostasis) or minimize the bacterial colonization on enamel surfaces without having pronounced antimicrobial properties. Examples are biomimetic approaches, i.e. based on selected salivary enzymes or hydroxyapatite.     

Bevölkerungswachstum: Bildung ist die Lösung

Population growth – education is the answer Over the last decades world population has been constantly growing by some 80 million per year. Whereas the growth rate as well as the fertility rate have been cut by half since the 1970th, population growth will continue well over mid‐century. As the developed countries have completed the demographic transition from high mortality and fertility rates to low ones, population growth is fading out there or has already been reversed into decline. In the least developed countries mortality has fallen as well, whereas fertility decline has stalled. Therefor population growth is very high making the solution of the widespread problems in this part of the world more and more difficult. One obvious way out of this trap would be a better education that could open new development perspectives. A positive side effect is that educated women have much less offspring than their counterparts who never went to school.     

Some notes on the vértesszöllös occipital

An examination of the Vértessz?ll?s occipital bone indicates the need for takings its condition and preservation as well as certain aspects of its morphology into account prior to a metric assessment of its features. This analysis confirms the presence of extrasutural bones on the lambdoidal suture as well as some distortion in the sagittal curvature of this region. The advisability of using the endocranial sutures as well as other data for defining lambda in cases such as this is discussed, and a procedure for determining the position of opisthion is indicated. A metric and morphological analysis is used to support the claim that the specimen can be considered a large late representative of Homo erectus in Europe.     

Preparation and in vitro antioxidant activities of 6‐amino‐6‐deoxychitosan and its sulfonated derivatives

The 6‐amino‐6‐deoxychitosan (NC) and their 2, 6‐di‐N‐sulfonated derivatives were prepared via N‐phthaloylation, tosylation, azidation, hydrazinolysis, reduction of azide groups and N‐sulfonation, and their structures were systematically characterized by FT‐IR, 2D HSQC NMR, XRD, gel permeation chromatography (GPC), and elemental analysis. The 6‐amino‐6‐deoxychitosan showed effect in three selected antioxidant essays, including reducing power, superoxide anion radical scavenging ability, and hydroxyl radical scavenging effect. But the factors affecting each activity were different. The reducing power and the superoxide anion radical scavenging ability of NC were strong and closely related to the amino groups in the molecular chains. Both introducing N‐sulfonated groups into NC and the concentration reduction of NC and its sulfonated derivatives decreased these activities. For the superoxide anion radical, the molecular charge property was also a significant influence factor. For the hydroxyl radical, NC only showed weak scavenging activity in a special inverse concentration‐dependent manner. However, the incorporation of N‐sulfonated groups significantly improved the scavenging activity, and the more N‐sulfonated groups, the higher the concentrations, the stronger the activity was. The results could be due to the different conformations of NC and its sulfonated derivatives in aqueous solution. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 539–549, 2015.