Structure/processing relationships in the fabrication of nanoporous gold

Nanoporous gold made by dealloying silver/gold alloys is a relatively new material finding application in catalysis, sensing, and other areas. Here we discuss the metallurgical processing required to make patterned foils of nanoporous gold with large, flat grains, with which we are exploring an application as substrates for the heterogeneous nucleation of protein crystals.     

Topical Delivery of Fluconazole: In Vitro Skin Penetration and Permeation Using Emulsions as Dosage Forms

ABSTRACT

We investigated in vitro skin penetration and permeation of fluconazole from emulsions containing different penetration enhancers. Fluconazole permeation was high (15–65% of the applied dose) across hairless mouse skin and low (8–9%) across pig ear skin. Permeation across mice skin from a formulation containing propyleneglycol and isopropyl myristate was significantly higher than that observed with the paraffin oil and propyleneglycol or Transcutol® emulsions. With pig skin, the paraffin oil or isopropyl myristate and propyleneglycol emulsions showed similar skin permeation and penetration. However, these emulsions provided epidermal concentrations higher than the minimal inhibitory concentrations for most dermatophytes.     

Comparative production of xylanase and the liberation of xylooligosaccharides from lignocellulosic biomass by Aspergillus brasiliensis BLf1 and recombinant Aspergillus nidulans XynC A773

We investigated the simultaneous production of xylanase and the liberation of xylooligosaccharides in rice husk solid‐state cultivations of Aspergillus brasiliensis BLf1 and by the recombinant Aspergillus nidulans XynC A773 strain. The bioprocess was optimised by experimental fractional design and response surface analysis. Results show that both fungi strains produced xylanases and their activities were dependent on the addition of basal medium, moisture content and the interactions between particle size and inoculum size, producing maximum xylanase activities of 230.7 U g^?1 substrate for A. brasiliensis, and 187.9 U g^?1 substrate for A. nidulans XynC. Xylooligosaccharides were liberated in the same cultures, with concentrations up to 17.6 mg g^?1 and 23.9 mg g^?1 of substrate for A. brasiliensis and A. nidulans XynC, respectively, both strains presenting similar profiles, with xylose residues varying from X3 to X6. These results suggest the possibility of lowering production costs of enzymes for food applications and oligosaccharides.     

Experimental Testing of Interfacial Coupling in Two-Phase Flow in Porous Media

Two-phase flow through natural porous media is affected by the interfacial coupling that takes place across the interfaces located in a porous medium. Such coupling may be of two types: viscous and capillary. In this study, defining equations for the capillary and viscous coupling parameters have been constructed. Moreover, these equations, together with a modified form of Kalaydjian's transport equations, have been used to analyze interfacial coupling in two-phase flow through porous media. On the basis of the analysis carried out, it is argued that interfacial coupling has no effect on steady-state, cocurrent flow, and only a small effect on unsteady-state, cocurrent flow. Moreover, it is suggested that interfacial coupling has a significant effect on steady-state, countercurrent flow. Two methods were used to test the theory. In the first method, data from steady-state, cocurrent, and countercurrent experiments were used to show that experimentally determined values of the capillary coupling parameters were in good agreement with those predicted theoretically. Because of experimental problems, it was not possible to determine experimentally, when using the first method, the magnitude of the viscous coupling parameters. In the second method, data from steady-state and unsteady-state, cocurrent flow experiments, using fluids having different viscosity ratios, and porous media having different grain-size distributions, were used to test the theory. Because of a lack of sufficient precision in the measured data, it was not possible to make definitive statements with respect to the adequacy of the theory, or the possible impact of viscosity ratio and grain-size distribution on capillary coupling. Moreover, for the same reason, it was not possible to obtain reliable estimates of the magnitude of the capillary coupling parameters. Because the second method is based on the assumption that viscous coupling is negligible, it was not possible to use this method to determine experimentally the magnitude of the viscous coupling parameters.     

Auditory habituation in young and older adults: The verbal transformation effect.

In 3 experiments, auditory massed repetition was used to examine age-related differences in habituation by means of the verbal transformation paradigm. Participants heard 10 words (5 high frequency and 5 low frequency), each presented 180 times, and they reported perceived changes in the repeated words (verbal transformations). In these experiments, older adults reported fewer illusory percepts than young adults. Older adults' loss of auditory acuity and slowing of processing, stimulus degradation (in young adults), and instructions biasing the report of these illusory percepts did not account for the fewer illusory percepts reported by the older adults. These findings suggest that older adults' reduced susceptibility to habituation arises from centrally located declines in the transmission of information within the word recognition pathway. The discussion focuses on the implications that these age-related declines may have on word identification during on-line speech perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

River segmentation using satellite image contextual information and Bayesian classifier

Satellite-based remote sensing imaging can provide continuous snapshots of the Earth’s surface over long periods. River extraction from remote sensing images is useful for the comprehensive study of dynamic changes of rivers over large areas. This paper presents a new method of extracting rivers by using training samples based on the mathematical morphology, Bayesian classifier and a dynamic alteration filter. The use of a training map from erosion morphology helps to extract the non-predictive river’s curves in the image. The algorithm has two phases: creating the profile to separate river area via evaluated morphological erosion and dilation, namely, a training map; and improving the river’s image segmentation using the Bayesian rule algorithm in which two consecutive filters swipe false positive (non-water area) along the image. The proposed algorithm was tested on the Kuala Terengganu district, Malaysia, an area that includes a river, a bridge, dam and a fair amount of vegetation. The results were compared with two standard methods based on visual perception and on peak signal-to-noise ratio, respectively. The novelty of this approach is the definition of the contextual information filtering technique, which provides an accurate extraction of river segmentation from satellite images.     

On the explicit analytic solutions of an Oldroyd 6-constant fluid

This paper deals with some steady unidirectional flows of an Oldroyd 6-constant fluid. The modelled differential equation is non-linear and proposes some new mathematical difficulties. The governing non-linear equation for the steady flow of an Oldroyd 6-constant fluid is different than from the Newtonian fluid and involves the non-Newtonian features. Moreover, the exact analytic solutions are obtained for Couette, Poiseuille and generalized Couette flows for all values of non-Newtonian parameters. The homotopy analysis method (HAM) is used to construct the solutions.     

Software assurance by bounded exhaustive testing

Bounded exhaustive testing (BET) is a verification technique in which software is automatically tested for all valid inputs up to specified size bounds. A particularly interesting case of BET arises in the context of systems that take structurally complex inputs. Early research suggests that the BET approach can reveal faults in small systems with inputs of low structural complexity, but its potential utility for larger systems with more complex input structures remains unclear. We set out to test its utility on one such system. We used Alloy and TestEra to generate inputs to test the Galileo dynamic fault tree analysis tool, for which we already had both a formal specification of the input space and a test oracle. An initial attempt to generate inputs using a straightforward translation of our specification to Alloy did not work well. The generator failed to generate inputs to meaningful bounds. We developed an approach in which we factored the specification, used TestEra to generate abstract inputs based on one factor, and passed the results through a postprocessor that reincorporated information from the second factor. Using this technique, we were able to generate test inputs to meaningful bounds, and the inputs revealed nontrivial faults in the Galileo implementation, our specification, and our oracle. Our results suggest that BET, combined with specification abstraction and factoring techniques, could become a valuable addition to our verification toolkit and that further investigation is warranted.     

A temporal-analysis-based pitch estimation system for noisy speech with a comparative study of performance of recent systems

In this paper, a new system of pitch estimation is presented. The system is designed to be robust to challenging noise conditions. This robustness to the presence of noise in the signal is achieved by developing a new representation of the speech signal, based on the operation of damped harmonic oscillators (DHOs), and temporal mode analysis of their output. The resulting representation is shown to possess qualities that are only gradually degraded in the presence of noise. A harmonic grouping based system is used to estimate the pitch frequency. This method is easily extended to simultaneously track the pitch of more than one speaker. In a series of experiments the accuracy and noise robustness of the proposed system was compared with that of a number of prominent pitch estimation and tracking systems. The results show that the proposed system's overall performance is much better than any of the other systems tested, especially in the presence of very large amounts of noise. Furthermore, the proposed system is comparatively inexpensive in terms of processing and memory requirements.