Insights into the chemical composition of Equisetum hyemale by high resolution Raman imaging

Equisetaceae has been of research interest for decades, as it is one of the oldest living plant families, and also due to its high accumulation of silica up to 25% dry wt. Aspects of silica deposition, its association with other biomolecules, as well as the chemical composition of the outer strengthening tissue still remain unclear. These questions were addressed by using high resolution (<1 μm) Confocal Raman microscopy. Two-dimensional spectral maps were acquired on cross sections of Equisetum hyemale and Raman images calculated by integrating over the intensity of characteristic spectral regions. This enabled direct visualization of differences in chemical composition and extraction of average spectra from defined regions for detailed analyses, including principal component analysis (PCA) and basis analysis (partial least square fit based on model spectra). Accumulation of silica was imaged in the knobs and in a thin layer below the cuticula. In the spectrum extracted from the knob region as main contributions, a broad band below 500 cm−1 attributed to amorphous silica, and a band at 976 cm−1 assigned to silanol groups, were found. From this, we concluded that these protrusions were almost pure amorphous, hydrated silica. No silanol group vibration was detected in the silicified epidermal layer below and association with pectin and hemicelluloses indicated. Pectin and hemicelluloses (glucomannan) were found in high levels in the epidermal layer and in a clearly distinguished outer part of the hypodermal sterome fibers. The inner part of the two-layered cells revealed as almost pure cellulose, oriented parallel along the fiber

Ultra-Fast Oleophobic-Hydrophilic Switching Surfaces for Anti-Fogging, Self-Cleaning, and Oil-Water Separation

Smooth copolymer–fluorosurfactant complex film surfaces are found to exhibit fast oleophobic–hydrophilic switching behavior. Equilibration of the high oil contact angle (hexadecane = 80°) and low water contact angle (110°), which, when combined with the inherent ultrafast switching speed, yields oil–water mixture separation efficiencies exceeding 98%

The impact of diabetes on the pathogenesis of sepsis

Diabetes is associated with an increased susceptibility to infection and sepsis. Conflicting data exist on whether the mortality of patients with sepsis is influenced by the presence of diabetes, fuelling the ongoing debate on the benefit of tight glucose regulation in patients with sepsis. The main reason for which diabetes predisposes to infection appears to be abnormalities of the host response, particularly in neutrophil chemotaxis, adhesion and intracellular killing, defects that have been attributed to the effect of hyperglycaemia. There is also evidence for defects in humoral immunity, and this may play a larger role than previously recognised. We review the literature on the immune response in diabetes and its potential contribution to the pathogenesis of sepsis. In addition, the effect of diabetes treatment on the immune response is discussed, with specific reference to insulin, metformin, sulphonylureas and thiazolidinediones

Biomechanics of the giant reed Arundo donax

The quantitative description of local buckling of hollow plant stems requires the knowledge of Young's modulus in the longitudinal and tangential directions for the different tissues of which the stem is composed. For thick-walled stems the shear modulus for the radial-tangential plane is needed for an advanced treatment of the process of ovalization. The primary causes of failure can be predicted if critical compressive strains in the longitudinal direction and critical tensile strains in the tangential direction are known. All of these mechanical properties and their variation along the length of the stem can be measured in Arundo donax