Triplex formation by pyrene-labelled probes for nucleic acid detection in fluorescence assays

Triplex-forming homopyrimidine oligonucleotides containing insertions of a 2'-5' uridine linkage featuring a pyrene moiety at the 3'-position exhibit strong fluorescence enhancement upon binding to double-stranded DNA through Hoogsteen base pairing. It is shown that perfect matching of the new modification to the base pair in the duplex is a prerequisite for strong fluorescence, thus offering the potential to detect single mutations in purine stretches of duplex DNA. The increase in the fluorescence signal was dependent on the thermal stability of the parallel triplex, so a reduction in the pH from 6.0 to 5.0 resulted in an increase in thermal stability from 25.0 to 55.0 degrees C and in an increase in the fluorescence quantum yield (Phi(F)) from 0.061 to 0.179, while the probe alone was fluorescently silent (Phi(F)=0.001-0.004). To achieve higher triplex stability, five nucleobases in a 14-mer sequence were substituted with alpha-L-LNA monomers, which provided a triplex with a T(m) of 49.5 degrees C and a Phi(F) of 0.158 at pH 6.0. Under similar conditions, a Watson-Crick-type duplex formed with the latter probe showed lower fluorescence intensity (Phi(F)=0.081) than for the triplex.     

Full‐scale test of trailing edge flaps on a Vestas V27 wind turbine: active load reduction and system identification

A full‐scale test was performed on a Vestas V27 wind turbine equipped with one active 70 cm long trailing edge flap on one of its 13 m long blades. Active load reduction could be observed in spite of the limited spanwise coverage of the single active trailing edge flap. A frequency‐weighted model predictive control was tested successfully on this demonstrator turbine. An average flapwise blade root load reduction of 14% was achieved during a 38 minute test, and a reduction of 20% of the amplitude of the 1P loads was measured. A system identification test was also performed, and an identified linear model, from trailing edge flap angle to flapwise blade root moment, was derived and compared with the linear analytical model used in the model predictive control design model. Flex5 simulations run with the same model predictive control showed a good correlation between the simulations and the measurements in terms of flapwise blade root moment spectral densities, in spite of significant differences between the identified linear model and the model predictive control design model. Copyright © 2013 John Wiley & Sons, Ltd.     

Gas pressure measurements during continuous hot pressing of particleboard

Knowledge about the development of the internal gas pressure during hot pressing of wood-based composites is important for the optimization of panel properties and production speed. The gas pressure heavily affects the thermodynamic conditions inside the wood furnish mat, and a too high maximum value at press opening might cause an impairment of the panel properties. In this paper, gas pressure and temperature measurements inside a particle mat while passing through a continuous hot press are presented for the first time. The measurements were performed with a transportable system, consisting of a steel tube attached to a miniature pressure transducer and a data logger. The particleboards had a target thickness of mainly 16 mm, but also of 28 mm and 38 mm, respectively. The measurements show a distinct horizontal gas pressure distribution in both directions, in production direction and across the mat’s width. In contrast, cross-sectional gas pressure gradients were only visible inside the panels after leaving the press. By comparing the gas pressure curves measured for particleboard with those for medium density fiberboard (MDF), characteristic differences became evident. Overall, the gas pressure is higher in MDF compared to particleboard. Finally, a comparison between the gas pressure levels measured for three different panel thicknesses showed a clear relation between panel thickness and gas pressure, with a decreasing panel thickness resulting in an increase in gas pressure. The results of this paper will contribute to our understanding about the events inside wood furnish mats during continuous hot pressing.     

A smart rotor configuration with linear quadratic control of adaptive trailing edge flaps for active load alleviation

The paper proposes a smart rotor configuration where adaptive trailing edge flaps (ATEFs) are employed for active alleviation of the aerodynamic loads on the blades of the NREL 5 MW reference turbine. The flaps extend for 20% of the blade length and are controlled by a linear quadratic (LQ) algorithm based on measurements of the blade root flapwise bending moment. The control algorithm includes frequency weighting to discourage flap activity at frequencies higher than 0.5 Hz. The linear model required by the LQ algorithm is obtained from subspace system identification; periodic disturbance signals described by simple functions of the blade azimuthal position are included in the identification to avoid biases from the periodic load variations observed on a rotating blade. The LQ controller uses the same periodic disturbance signals to handle anticipation of the loads periodic component. The effects of active flap control are assessed with aeroelastic simulations of the turbine in normal operation conditions, as prescribed by the International Electrotechnical Commission standard. The turbine lifetime fatigue damage equivalent loads provide a convenient summary of the results achieved with ATEF control: 10% reduction of the blade root flapwise bending moment is reported in the simplest control configuration, whereas reductions of approximately 14% are achieved by including periodic loads anticipation. The simulations also highlight impacts on the fatigue damage loads in other parts of the structure, in particular, an increase of the blade torsion moment and a reduction of the tower fore‐aft loads. Copyright © 2014 John Wiley & Sons, Ltd.     

Proteomic profiles of white sucker (Catostomus commersonii) sampled from within the Thunder Bay Area of Concern reveal up-regulation of proteins associated with tumor formation and exposure to environmental estrogens

White sucker (Catostomus commersonii) sampled from the Thunder Bay Area of Concern were assessed for health using a shotgun approach to compile proteomic profiles. Plasma proteins were sampled from male and female fish from a reference location, an area in recovery within Thunder Bay Harbour, and a site at the mouth of the Kaministiquia River where water and sediment quality has been degraded by industrial activities. The proteins were characterized using reverse-phase liquid chromatography tandem to a quadrupole-time-of-flight (LC-Q-TOF) mass spectrometer and were identified by searching in peptide databases. In total, 1086 unique proteins were identified. The identified proteins were then examined by means of a bioinformatics pathway analysis to gain insight into the biological functions and disease pathways that were represented and to assess whether there were any significant changes in protein expression due to sampling location. Female white sucker exhibited significant (p = 0.00183) site-specific changes in the number of plasma proteins that were related to tumor formation, reproductive system disease, and neurological disease. Male fish plasma had a significantly different (p < 0.0001) number of proteins related to neurological disease and tumor formation. Plasma concentrations of vitellogenin were significantly elevated in females from the Kaministiquia River compared to the Thunder Bay Harbour and reference sites. The protein expression profiles indicate that white sucker health has benefited from the remediation of the Thunder Bay Harbour site, whereas white sucker from the Kaministiquia River site are impacted by ongoing contaminant discharges.     

Interconverting conformations of variants of the human amyloidogenic protein beta2-microglobulin quantitatively characterized by dynamic capillary electrophoresis and computer simulation

Capillary electrophoretic separation profiles of cleaved variants of beta2-microglobulin (beta2m) reflect the conformational equilibria existing in solutions of these proteins. The characterization of these equilibria is of interest since beta2m is responsible for amyloid formation in dialysis-related amyloidosis and thus is able to attain alternative conformations that lead to irreversible aggregation and precipitation. In this study, we quantitate the increased conformational instability of cleaved beta2m by extracting rate constants and activation energies by simulating the experimental data using a unified theory for dynamic chromatography and dynamic electrophoresis. The results are correlated with the outcome of independent experiments based on mass spectrometric measurement of H/D exchange. This study illustrates that dynamic capillary electrophoresis is suitable for the investigation of the interconversion of protein conformations of amyloidogenic molecules and is not only restricted to ideal model compounds.     

Vectorial modeling of near-field imaging with uncoated fiber probes: transfer function and resolving power

Using exact 3D vectorial simulations of radiation coupling into uncoated dielectric fiber probes, we calculate amplitude transfer functions for conical single-mode fiber tips at the light wavelength of 633 nm. The coupling efficiency of glass fiber tips is determined in a wide range of spatial frequencies of the incident radiation for opening angles varying from 30 degrees to 120 degrees . The resolution in near-field imaging with these tips is considered for field distributions limited in both direct and spatial-frequency space. The characteristics of the transfer functions describing the relation between probed optical fields and near-field images are analyzed in detail. The importance of utilizing a perfectly sharp tip is also examined.     

Scheduling and development support in the Scavenger cyber foraging system

Cyber foraging is a pervasive computing technique where small mobile devices offload resource intensive tasks to stronger computing machinery in the vicinity.One of the main challenges within cyber foraging is that it is very difficult to develop cyber foraging enabled applications. An application using cyber foraging is working with mobile, distributed and, possibly, parallel computing; fields within computer science notoriously hard for programmers to grasp.This paper presents Scavenger—a cyber foraging system supporting easy development of mobile cyber foraging applications, while still delivering efficient, mobile use of remote computing resources through the use of a custom built mobile code execution environment and a new adaptive, dual-profiling scheduler.     

Numerical simulations of wake characteristics of a wind turbine in uniform inflow

The wake of a wind turbine operating in a uniform inflow at various tip speed ratios is simulated using a numerical method, which combines large eddy simulations with an actuator line technique. The computations are carried out in a numerical mesh with about 8.4·10⁶ grid points distributed to facilitate detailed studies of basic features of both the near and far wake, including distributions of interference factors, vortex structures and formation of instabilities. Copyright © 2009 John Wiley & Sons, Ltd.     

Technoeconomic analysis of a low CO2 emission dimethyl ether (DME) plant based on gasification of torrefied biomass

Two models of a dimethyl ether (DME) fuel production plant were designed and analyzed in DNA and Aspen Plus. The plants produce DME by either recycle (RC) or once through (OT) catalytic conversion of a syngas generated by gasification of torrefied woody biomass. Torrefication is a mild pyrolysis process that takes place at 200–300 °C. Torrefied biomass has properties similar to coal, which enables the use of commercially available coal gasification processing equipment. The DME plants are designed with focus on lowering the total CO₂ emissions from the plants; this includes e.g. a recycle of a CO₂ rich stream to a CO₂ capture plant, which is used in the conditioning of the syngas.