Total body analysis of rats with special regard to fat determination. Possibility of determining fat and proteins by calculation

The authors present a method for the whole body analysis of rats which combines the animal body preparation according to Mickelsen with the lipid analysis according to Folch; the liquid analysis has been somewhat modified. In this way and by the non-gutting of the animals, the determination of the body fat becomes less laborious. The body fat content can also be calculated from the water content. The body water content was determined gravimetrically. The body protein content was determined according to Kjeldahl; the protein content may also be calculated from the fat and water contents if an error range of +1% is acceptable.     

A 14 ns 256 K×1 CMOS SRAM with multiple test modes

A methodology to enter and exit from test modes in asynchronous static RAMs (SRAMs) is presented. This chip is fabricated in a 0.7 μm twin-tub, single-poly, double-metal technology on p/p⁺ epitaxial substrate. To prevent hot-electron degradation, a voltage regulator is used in the memory matrix, with the cascoding technique applied in the periphery. Circuits were implemented against voltage bumps and data glitching on the output. A small cell size of 5.1×13.7 μm² and a chip size of 3.9×9.5 mm² have been achieved     

Material characterization by J-R curves of a 20MnMoNi55 forging

J-R curves have been determined for one specific forging of the reactor pressure vessel steel 20MnMoNi55 to characterize its fracture resistance in the upper shelf toughness regime. The multiple specimen unloading (MSU), a direct current potential drop (DCPD), and the single specimen partial unloading compliance (SSPUC) methods have been applied to test different CT-specimen geometries at temperatures between 25 and 300°C.The J–R curves are temperature dependent showing a minimum of slope and absolute values at 200°C. The critical J-values for onset of stable crack growth in the scatter of the results are independent of temperature and geometry: J_i ≈ 180 kJ/m². The values of the technical initiation toughness J_IC according to ASTM E813⁷ and according to Loss et al. (1979),⁸ the tearing modulus T, and the instability parameter J₅₀ show corresponding temperature trends as the J-R curves with a minimum at about 200°C.The material data have been used to evaluate the ductile failure initiation and tearing instability of several structural tests. The quality of agreement between calculable predictions and experiments is shown to depend on the input material J-R curve and evaluation of the loading which requires detailed knowledge about the material stress-strain behaviour and the relevant crack tip constraint.     

Three-dimensional reconstruction and motion analysis of living, crawling cells

Cell behavior is three-dimensional (3-D), even when it takes place on a flat surface. Migrating cells form pseudopods on and off the substratum, and the cell body undergoes height changes associated with a 1 min behavior cycle. Inside the cell, the nucleus has a 3-D migratory cycle, and vesicles move up and down in the z-axis as a cell locomotes. For these reasons, the two-dimensional (2-D) analysis of cellular and subcellular behavior is, in many cases, inadequate. We have, therefore, developed 3-D motion analysis systems that reconstruct the cell surface, nucleus, pseudopods, and vesicles of living, crawling cells in 3-D at time intervals as short as 1 s, and compute more than 100 parameters of motility and dynamics morphology at 1-s intervals. We are now in the process of developing a multimode reconstruction system that will allow us to reconstruct and analyze fluorescently tagged molecular complexes within the differential interference contrast-imaged subcellular architecture of a crawling cell. These evolving technologies should find wide application for a host of biomedical problems.     

High-order waveguide modes in ZnO nanowires

We use tapered silica fibers to inject laser light into ZnO nanowires with diameters around 250 nm to study their waveguiding properties. We find that high-order waveguide modes are frequently excited and carry significant intensity at the wire surface. Numerical simulations reproduce the experimental observations and indicate a coupling efficiency between silica and ZnO nanowires of 50%. Experimentally, we find an emission angle from the ZnO nanowires of about 90 degrees , which is in agreement with the simulations.     

Regular dislocation networks in silicon as a tool for nanostructure devices used in optics, biology, and electronics

Well-controlled fabrication of dislocation networks in Si using direct wafer bonding opens broad possibilities for nanotechnology applications. Concepts of dislocation-network-based light emitters, manipulators of biomolecules, gettering and insulating layers, and three-dimensional buried conductive channels are presented and discussed. A prototype of a Si-based light emitter working at a wavelength of about 1.5 microm with an efficiency potential estimated at 1% is demonstrated.     

Assessing the impact of changes in landuse and management practices on the diffuse pollution and retention of nitrate in a riparian floodplain

In many European lowland rivers and riparian floodplains diffuse nutrient pollution is causing a major risk for the surface waters and groundwater to not achieve a good status as demanded by the European Water Framework Directive. In order to delimit the impact of diffuse nutrient pollution substantial and often controversial changes in landuse and management are under discussion. In this study we investigate the impact of two complex scenarios considering changes in landuse and land management practices on the nitrate loads of a typical lowland stream and the riparian groundwater in the North German Plains. Therefore the impacts of both scenarios on the nitrate dynamics, the attenuation efficiency and the nitrate exchange between groundwater and surface water were investigated for a 998.1 km(2) riparian floodplain of the Lower and Central Havel River and compared with the current conditions. Both scenarios target a substantial improvement of the ecological conditions and the water quality in the research area but promote different typical riparian landscape functions and consider a different grade of economical and legal feasibility of the proposed measures. Scenario 1 focuses on the optimisation of conservation measures for all natural resources of the riparian floodplain, scenario 2 considers measures in order to restore a good status of the water bodies mainly. The IWAN model was setup for the simulation of water balance and nitrate dynamics of the floodplain for a perennial simulation period of the current landuse and management conditions and of the scenario assumptions. The proposed landuse and management changes result in reduced rates of nitrate leaching from the root zone into the riparian groundwater (85% for scenario 1, 43% for scenario 2). The net contributions of nitrate from the floodplain can be reduced substantially for both scenarios. In case of scenario 2 a decrease by 70% can be obtained. For scenario 1 the nitrate exfiltration rates to the river drop even below the infiltration rates from the river, the riparian floodplain in that scenario represents a net sink for river derived nitrate. As the nitrate contributions from the investigated riparian floodplain represent only a small proportion of the total nitrate loads within the river (1% p.a.) the overall impact of the scenario measures on the nitrate loads at the river outlet remains small. However, during the ecologically most sensitive summer periods under current conditions nitrate contributions from the riparian groundwater of the Lower and Central Havel River (which covers only 5% of the area of the Havel catchment) represent more than 20% of the river loads. By the implementation of the investigated landuse changes within the research area the groundwater derived nitrate contributions could be halved to only 10% during summer baseflow conditions.     

A CD14 domain with lipopolysaccharide-binding and -neutralizing activity

The interaction of lipopolysaccharide with CD14 plays a key role in signaling that activates an early defense against pathogens but also contributes to the development of sepsis and septic shock. Here we have mapped the entire 356-amino-acid protein with synthetic 20-amino-acid peptides and have identified a new lipopolysaccharide-binding domain with a strong LPS-neutralizing activity. Moreover, analysis of the structure-activity relationship of this peptide, which corresponds to amino acids 81-100 of human CD14, revealed that leucines 87, 91, and 94 are essential for these activities. The functional relevance of these residues was confirmed by cellular expression of mutant CD14 proteins that are no longer able to bind LPS. Furthermore, the peptide provided a basis for the generation of highly soluble analogues with stronger lipopolysaccharide-neutralizing activity.     

Bidirectional reflectance of dry and submerged Labsphere Spectralon plaque

We present the bidirectional reflectance of a Labsphere calibration plaque, both dry and submerged in water, at normal illumination. The measurements indicate that when submerged in water, the Labsphere calibration plaque has a higher reflectance value than when dry at viewing angles below 55 degrees . The results are presented in the form of a reflectance factor and are useful for calibrating underwater reflectance measurements.