Hay Component Sieving by a Rotary Sieve with Lifting Flights

In order to improve drying of hay-composed materials, the already dried parts must be extracted from the mixture to save energy and avoid quality problems. A separation test of a mixture of leaf and stems of ryegrass and clover for hay was developed for this, using a rotary sieve with lifter flights and the vegetal material at several moisture contents. The best separation results were found for the dried state and rotation speed of 2.1 sec^?1. The stems' separation efficiencies were between 74 and 96%.     

The multi-layered protective cuticle of Collembola: a chemical analysis

Collembola, also known as springtails, are soil-dwelling arthropods that typically respire through the cuticle. To avoid suffocating in wet conditions, Collembola have evolved a complex, hierarchically nanostructured, cuticle surface that repels water with remarkable efficiency. In order to gain a more profound understanding of the cuticle characteristics, the chemical composition and architecture of the cuticle of Tetrodontophora bielanensis was studied. A stepwise removal of the different cuticle layers enabled controlled access to each layer that could be analysed separately by chemical spectrometry methods and electron microscopy. We found a cuticle composition that consisted of three characteristic layers, namely, a chitin-rich lamellar base structure overlaid by protein-rich nanostructures, and a lipid-rich envelope. The specific functions, composition and biological characteristics of each cuticle layer are discussed with respect to adaptations of Collembola to their soil habitat. It was found that the non-wetting characteristics base on a rather typical arthropod cuticle surface chemistry which confirms the decisive role of the cuticle topography.     

Evidence from spectral emissometry for conduction intraband transitions in the intrinsic regime for silicon

From emissometry measurements in lightly doped Si at elevated temperatures, we have observed an anomalous absorption band in the wavelength range of 1–5 μm. The wavelength at which the band peaks, λ≈2.3 μm, shows a negligible dependence on temperature while the peak intensity increases with temperature presumably as a result of the increasing intrinsic carrier concentration. Spitzer and Fan reported a similar absorption band in direct absorption measurements at room temperature for n-type Si with extrinsic electron concentrations of 10¹⁴ to 10¹⁹cm⁻³. No such structure was found in extrinsic p-type Si. Spitzer and Fan were unable to identify the mechanism for this anomalous absorption. In both the experiments, this absorption of free electrons is due to intraband transitions in the conduction band from the Δ₁ conduction band edge across an energy gap of E ∼ 0.5 eV to a higher lying Δ₂′ conduction band.     

Delayed luminescence in a molecularly doped polymer (TAPC in polycarbonate)

Decay of the delayed luminescence of 1,1-bis(di-4-tolylaminophenyl)cyclohexane, both doped into a polycarbonate binder and matrix-isolated in an MTHF glass, has been studied upon excitation with the 308 nm line of an excimer laser. Time-resolved emission spectra have also been recorded. In the early time regime, 30 ns < t < 10 μs, the decay of the emission, identified as delayed fluorescence rather than phosphorescence, follows a power-law characteristic of geminate pair recombination in a disordered medium. Singlet–singlet excitation fusion is considered to be the main pathway for geminate pair formation. Fusion of triplet excitations becomes important for e–h pair formation at long times only (10 μs < t < 10 ms). The rate of triplet–triplet encounters carries a time dependence characteristic of the random walk of excitations in a disordered solid.     

Fibrillar Elastomeric Micropatterns Create Tunable Adhesion Even to Rough Surfaces

Biologically inspired, fibrillar dry adhesives continue to attract much attention as they are instrumental for emerging applications and technologies. To date, the adhesion of micropatterned gecko‐inspired surfaces has predominantly been tested on stiff, smooth substrates. However, all natural and almost all artificial surfaces have roughnesses on one or more different length scales. In the present approach, micropillar‐patterned PDMS surfaces with superior adhesion to glass substrates with different roughnesses are designed and analyzed. The results reveal for the first time adhesive and nonadhesive states depending on the micropillar geometry relative to the surface roughness profile. The data obtained further demonstrate that, in the adhesive regime, fibrillar gecko‐inspired adhesive structures can be used with advantage on rough surfaces; this finding may open up new applications in the fields of robotics, biomedicine, and space exploration.     

Magnetic and Acoustically Active Lipospheres for Magnetically Targeted Nucleic Acid Delivery

With the aim of obtaining a carrier for combined magnetic‐field‐ and ultrasound‐targeted nucleic acid delivery, acoustically active lipospheres are prepared that comprise magnetic nanoparticles and plasmid DNA or synthetic siRNA. The lipospheres, with average diameters of 5 μm and smaller, are obtained upon shaking a mixture of soybean oil, a cationic lipid, magnetic nanoparticles, a nucleic acid, and aqueous buffer in a perfluoropropane atmosphere in a sealed vial. These lipospheres create contrast in ultrasound imaging and display greatly increased magnetophoretic mobility and in consequence greatly improved magnetic retention in a flow model when compared with free magnetic nanoparticles. In cell culture, the lipospheres are sedimented within minutes to the surface of cells using a gradient magnetic field. This sedimentation results in the association of about 50% of the applied plasmid DNA with the cells and in functional DNA and siRNA delivery in vitro. Under these conditions, ultrasound does not have an enhancing effect on nucleic acid delivery. When magnetic, acoustically active lipospheres carrying 125iodine‐labeled plasmid DNA are injected into the tail veins of mice, the application of a gradient magnetic field to the chests of the mice results in a two‐ to threefold enrichment of both lung lobes with the plasmid. A similar enrichment is obtained when ultrasound alone (1 MHz, 10 min) is applied. The combined application of magnetic field and ultrasound has no synergistic effect in terms of liposphere capture in the lungs. Histological analysis reveals intact lipospheres in lung capillaries. A synergistic effect of magnetic field and ultrasound is observed in site‐specific plasmid deposition in a dorsal skinfold chamber model in mice after injection into the carotis. These conditions also result in functional plasmid delivery to the vasculature after intrajugular injection.     

A Developmental Route to Local Specificity. Nested Catenaries

Architect Defne Sunguroğlu Hensel and engineer Guillem Baraut Bover describe the Nested Catenaries design and construction system they have developed as part of a research project at the Oslo School of Architecture and Design (AHO). They explain how their innovative development of an unreinforced masonry shell structure made up of a single layer of bricks is informed by ancient building traditions and has been further evolved to be attuned to local context.     

Quantitative hepatitis C RNA-polymerase chain reaction and detection with DNA-ELISA

BACKGROUND/AIMS: Viral serum concentrations are considered to have a clinical, prognostic and epidemiological impact on patients with hepatitis C infection. The purpose of this study was to test whether quantitation of HCV-RNA is possible by PCR in combination with DNA-ELISA. METHODOLOGY: PCR with 25 to 35 cycles was performed with variable concentrations of cloned HCV-cDNA or the serum of patients with chronic hepatitis C. The amplified PCR-products were detected by agarose gel or by DNA-ELISA. RESULTS: The detection limit of PCR with DNA-ELISA or gel detection decreased with increasing numbers of PCR cycles. However, the correlation of the optical density of the DNA-ELISA with the HCV-cDNA concentration decreased with increasing numbers of PCR as well (r=0.8 vs. r=0.29; 25 vs. 35 PCR-cycles). HCV-RNA was found in the sera of 19 of 30 patients (63%) with chronic hepatitis C by gel detection and in 14 of 30 patients (47%) by DNA-ELISA subsequent to PCR with 35 cycles. CONCLUSIONS: The PCR/DNA-ELISA technique allows a semiquantitative determination of HCV-cDNA concentrations down to 103 genomes/ul. However, to obtain a reasonable sensitivity for HCV concentrations in the serum of patients with hepatitis C, the number of PCR cycles has to be increased to numbers too high to provide reliable quantification. Further studies should be done to evaluate whether the detection systems can be improved to obtain a sufficient sensitivity for quantitative HCV-PCR. A prerequisite for the use of PCR in combination with quantifiable detection systems is that a PCR-cycle number is chosen that keeps amplification within the logarithmic phase.