A small,simple sorghum decorticating device

A small commercially available laboratory mill was found to be suitable to dehull small batches of sorghum grain. The device used one grinding plate and an agitating dimpled plate and took about 1 min to adequately dehull the grain. At the completion of dehulling period decorticated grain was collected directly in a sample holder. Data from various cultivars, grain sizes and types of grain were reproducible. It only required 10 s to clear the device between samples.     

Soil erosion by rainfall and runoff—state of the art

The processes of soil detachment and sediment transport by rainfall and overland flow and resulting sediment transport are described. The results of past research on the role of raindrop impact in detaching soil, experimental studies of erosion, and erosion modelling are presented. Studies of soil loss from experimental field plots led to the development of the Universal Soil Loss Equation and to its subsequent modification for use in quantifying erosion by individual storms. Systems to produce rainfall for erosion studies in the laboratory are described. A system which is currently being calibrated and used for erosion control system testing at Drexel University's Geosynthetic Research Institute (GRI) is described. Preliminary spatial rainfall distributions and runoff measurements are presented. Experimental results obtained by others on the performance of natural and geosynthetic erosion control systems are discussed along with a proposed experimental program for the GRI system.     

Synchronous electrorotation of nanowires in fluid

We demonstrate electrorotation of metal nanowires phase-locked to a driving alternating current electric field. Field rotation was accomplished by a low-frequency signal that modulates the amplitude of the high-frequency field. Steady, synchronous rotation of the nanowires was observed for frequencies up to a maximum rotational frequency, which depends on the magnitude of the applied electric field. A locally two-dimensional nanowire fluid flow model was developed to calculate the viscous fluid drag torque, including drag contributions due to the proximity of the floor. Synchronicity and phase-lock angle predicted by equating the calculated fluid drag and electrical driving torques is in good agreement with experimentally determined values, which provides support for the model. Synchronous electrorotation allows for precise control of nanowire rotational speed and orientation for frequencies as low as a fraction of 1 Hz. Potential applications include reconfigurable polarization filters, microfluidic valves, and stirring devices.     

Towards a quantitative understanding of the within-host dynamics of influenza A infections

Although the influenza A virus has been extensively studied, a quantitative understanding of the infection dynamics is still lacking. To make progress in this direction, we designed several mathematical models and compared them with data from influenza A infections of mice. We find that the immune response (IR) plays an important part in the infection dynamics. Both an innate and an adaptive IR are required to provide adequate explanation of the data. In contrast, regrowth of epithelial cells did not seem to be an important mechanism on the time scale of the infection. We also find that different model variants for both innate and adaptive responses fit the data well, indicating the need for additional data to allow further model discrimination.     

'Progressive' versus 'indolent' idiopathic membranous glomerulonephritis

There is still controversy about safe and effective therapy for idiopathic membranous glomerulonephritis (MGN). Over 20 years, we have simply observed our patients clinically after diagnosis, and only used aggressive therapy with steroids in high dosage and azathioprine for 21 patients with progressive renal failure. The other 42 were thus classified as 'indolent' MGN. Those with 'progressive' MGN had heavier proteinuria and worse renal function on presentation, but the overlap was considerable. Patients with progressive MGN were treated after 1-4 years. All responded promptly, and 5 years after presentation all were alive, and only one was on dialysis. By 10 years, most were still alive, and of these most were off dialysis. In five patients, dialysis was delayed by several years. There were two deaths on dialysis, and three other deaths, mostly in older patients. All but one patient with indolent MGN remained stable on symptomatic treatment only, for at least 5 years after presentation. In many, proteinuria fell to insignificant levels over 4 years. In these remitting patients, there was a prevalence of thyroid disease (7), rheumatoid disease (3) and nephrotic presentation in pregnancy (4). After 6-10 years three patients developed worsening proteinuria and renal failure. Five older patients died from unrelated causes.     

On the separability of catalytic deactivation kinetics

An analysis of deactivation kinetics for a number of model surfaces reveals that formulation in terms of a separable activity factor is correct only fo Further there is no apparent general correlation between the separable analysis and the correct treatment.     

Interrelationship of chemical characterization and rheological behaviour of coal liquefaction bottoms

In the development of the Exxon Donor Solvent (EDS) process, bituminous and subbituminous coals have been processed in a one ton-per-day coal liquefaction pilot plant using the feed coal slurried with solvent and with or without bottoms recycle. The liquefaction bottoms from both once-through and bottoms recycle operation exhibit non-Newtonian viscometric behaviour. The recycled bottoms, however, are more viscosity/shear dependent, less viscosity/temperature dependent and more thermally stable than the once-through bottoms. Chemical characterization of these bottoms reveals that alkyl and phenoxy groups are important functional groups responsible for the viscometric behaviour of bottoms. The increase of bottoms viscosity is postulated to involve the elimination/condensation of methylene units are phenolic functional groups to form the crosslinkages of large aromatic clusters.     

How sticky should a virus be? The impact of virus binding and release on transmission fitness using influenza as an example

Budding viruses face a trade-off: virions need to efficiently attach to and enter uninfected cells while newly generated virions need to efficiently detach from infected cells. The right balance between attachment and detachment—the right amount of stickiness—is needed for maximum fitness. Here, we design and analyse a mathematical model to study in detail the impact of attachment and detachment rates on virus fitness. We apply our model to influenza, where stickiness is determined by a balance of the haemagglutinin (HA) and neuraminidase (NA) proteins. We investigate how drugs, the adaptive immune response and vaccines impact influenza stickiness and fitness. Our model suggests that the location in the ‘stickiness landscape’ of the virus determines how well interventions such as drugs or vaccines are expected to work. We discuss why hypothetical NA enhancer drugs might occasionally perform better than the currently available NA inhibitors in reducing virus fitness. We show that an increased antibody or T-cell-mediated immune response leads to maximum fitness at higher stickiness. We further show that antibody-based vaccines targeting mainly HA or NA, which leads to a shift in stickiness, might reduce virus fitness above what can be achieved by the direct immunological action of the vaccine. Overall, our findings provide potentially useful conceptual insights for future vaccine and drug development and can be applied to other budding viruses beyond influenza.     

Bottom-up assembly of large-area nanowire resonator arrays

Directed-assembly of nanowire-based devices will enable the development of integrated circuits with new functions that extend well beyond mainstream digital logic. For example, nanoelectromechanical resonators are very attractive for chip-based sensor arrays because of their potential for ultrasensitive mass detection. In this letter, we introduce a new bottom-up assembly method to fabricate large-area nanoelectromechanical arrays each having over 2,000 single-nanowire resonators. The nanowires are synthesized and chemically functionalized before they are integrated onto a silicon chip at predetermined locations. Peptide nucleic acid probe molecules attached to the nanowires before assembly maintain their binding selectivity and recognize complementary oligonucleotide targets once the resonator array is assembled. The two types of cantilevered resonators we integrated here using silicon and rhodium nanowires had Q-factors of approximately 4,500 and approximately 1,150, respectively, in vacuum. Taken together, these results show that bottom-up nanowire assembly can offer a practical alternative to top-down fabrication for sensitive chip-based detection.