A recombination event occurring within two complex 5q13.1 microsatellite repeat polymorphisms suggests a telomeric mapping of spinal muscular atrophy

The gene for the childhood spinal muscular atrophies (SMAs) has been mapped to 5q13.1. The interval containing the SMA gene has been defined by linkage analysis as 5qcen-D5S629-SMA-D5S557-5qter. We have identified a recombination event within this interval on a type-I SMA chromosome. The recombination maps to a region of multilocus microsatellite repeat (MSR) markers, and occurs between different subloci of two such markers, CMS-1 and 7613. While the possibility of a novel mutation caused by the recombination cannot be discounted, we believe when viewed in the context of a similar recombination in a Dutch SMA family, a centromeric boundary at the recombination site for the critical SMA interval is likely. This new proximal boundary would reduce the minimal region harboring the SMA locus from approximately 1.1 Mb to approximately 600 kb.     

Interaction of urea with triple superphosphate in a simulated fertilizer band

Fertilizer nutrient diffusion from fertilizer bands and transformations in soil can affect fertilizer nutrient availability to crops and knowledge of the transformations is necessary for proper management. The interaction of urea and triple superphosphate (TSP) on urea hydrolysis and P transformations during diffusion processes from a fertilizer band was evaluated in a laboratory incubation experiment with two eastern Canadian soils (Ste Rosalie clay, Modifiers Typic Humaquept, pH 5.0; Ormstown silty clay loam, Modifiers Typic Humaquept, pH 6.0). Two fertilizer sources (urea and TSP) and three N and P rates (0, 100 and 200 kg ha^–1) were combined in a factorial arrangement. Fertilizer combinations were placed on segmented soil columns, incubated and segments were analyzed for N and P content. Acidification from dissolution of TSP retarded urea hydrolysis, and curtailed the rise in soil pH surrounding the fertilizer band. Urea hydrolysis caused dissolution of organic matter in soils, which might inhibit precipitation of insoluble phosphates. Banding urea with TSP increased 1M KCl extractable soil P, soil solution P, sorbed P concentration and total P diffused away from the band. Urea decreased 0.01M CaCl₂ extractable P, indicating probable precipitation of calcium phosphates with CaCl₂ extraction. Banding urea with TSP could benefit P diffusion to plant roots in low Ca soils and increase fertilizer P availability.     

Development of a microfabricated electrochemical-cantilever hybrid platform

The design and fabrication of a combined electrochemical-cantilever microfluidic system is described. A chip integrating cantilevers with electrodes into a microchannel is presented with the accompanying polymer flow cell. Issues such as electrical and fluid connections are addressed, electromechanical behavior in ionic solution is investigated, and two uses of the system are demonstrated. First, all cantilevers are functionalized with cysteine, to facilitate detection of Cu²⁺ ions, then one cantilever is electrochemically cleaned in situ to generate a reference cantilever for differential measurements. Two concentrations of Cu²⁺ ions are successfully measured in this way. Clean cantilevers are used to probe a solution with and without [Fe(CN)₆]^3−/4− redox couple present, demonstrating the combined voltammetric and deflection readout.     

Evaluation of Dynamic Channel and Power Assignment for Cognitive Networks

In this paper, we develop a unifying optimization formulation to describe the Dynamic Channel and Power Assignment (DCPA) problem and an evaluation method for comparing DCPA algorithms. DCPA refers to the allocation of transmit power and frequency channels to links in a cognitive network so as to maximize the total number of feasible links while minimizing the aggregate transmit power. We apply our evaluation method to five representative DPCA algorithms proposed in the literature. This comparison illustrates the tradeoffs between control modes (centralized versus distributed) and channel/power assignment techniques. We estimate the complexity of each algorithm. Through simulations, we evaluate the effectiveness of the algorithms in achieving feasible link allocations in the network, and their power efficiency. Our results indicate that, when few channels are available, the effectiveness of all algorithms is comparable and thus the one with smallest complexity should be selected. The Least Interfering Channel and Iterative Power Assignment algorithm does not require cross-link gain information, has the overall lowest run time, and achieves the highest feasibility ratio of all the distributed algorithms; however, this comes at a cost of higher average power per link.     

Familiarity for associations? A test of the domain dichotomy theory.

Episodic recognition memory is mediated by functionally separable retrieval processes, notably familiarity (a general sense of prior exposure) and recollection (the retrieval of contextual details), whose relative engagement depends partly on the nature of the information being retrieved. Currently, the specific contribution of familiarity to associative recognition memory (where retrieval of the relationships between pairs of stimuli is required) is not clearly understood. In this study, we tested domain dichotomy theory, which predicts that familiarity should contribute more to associative memory when stimuli are similar (within-domain) than when they are distinct (between-domain). Participants studied stimulus pairs, and at test, discriminated intact from rearranged pairs. Stimuli were either within-domain (name–name or image–image pairs) or between-domain (name–image pairs). Across experiments we used 2 different behavioral measures of familiarity based on receiver operating characteristic curves and a modified remember–know procedure. Both experiments provided evidence that familiarity can contribute to associative recognition; however, familiarity was stronger for between-domain pairs, in direct contrast to the domain dichotomy prediction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Jominy end quench for light-weight alloy development

The Jominy end quench test is well known as a method of measuring hardenability in steels. In nonferrous alloys, there is a desire to determine the effect of quenching on final properties after heat treating. The Jominy end quench test offers a method for studying many quenching conditions with a minimum of samples. The potential for developing a new understanding of the complex response of nonferrous alloys to processing conditions, especially quenching, will be presented. Examples of the properties measured on Jominy end quench specimens of aluminum and titanium alloys will be presented.     

Water Content and Water Evolution from Reaction-Bonded Aluminum Oxide (RBAO) Powder Precursors

Water evolution behavior from reaction-bonded aluminum oxide (RBAO) powder precursor was studied by the Carl-Fischer titration method. RBAO mixtures were milled for 4 and 8 h in absolute ethanol and water–ethanol mixtures containing 5 and 10 vol% water. The water content was then determined under dynamic heating conditions from 20°C to 250°C and static heating at 250°C. When the aluminum content is increased from 30 to 60 vol%, the water content of the milled powder precursor mixtures also increased. The higher water contents observed in powders milled in absolute ethanol are discussed in terms of the possible interaction of the ethanol with the surface of the aluminum particles.     

TLC and <Superscript>31</Superscript>P-NMR Analysis of Low Polarity Phospholipids

High-performance TLC and ³¹P-NMR were assessed as methods of observing the presence of numerous low polarity phospholipids: bis-phosphatidic acid (BPA), semi-lyso bis-phosphatidic acid (SLBPA), N-acyl phosphatidylethanolamine (NAPE), N-(1,1-dimethyl-3-oxo-butyl)-phosphatidylethanolamine (diacetone adduct of PE, DOBPE), N-acetyl PE, phosphatidylmethanol (PM), phosphatidylethanol (PEt), phosphatidyl-n-propanol (PP), phosphatidyl-n-butanol (PB). Both techniques are non-discriminative and do not require the prior isolation of individual lipids. It appears that 2D TLC is superior to ³¹P NMR in the analysis of low polarity phospholipids. All phosphatidylalcohols were well separated by 2D TLC. However, some compounds which can present difficulty in separation by 2D-TLC (e.g., SLBPA and NAPE; or DOBPE and N-acetyl PE) were easily distinguished using ³¹P NMR so the methods are complimentary. A disadvantage of 2D TLC is that Rf values can vary with different brands and batches of TLC plates. The chemical shifts of ³¹P NMR were less variable, and so a library of standards may not be necessary for peak identification. Another advantage of ³¹P NMR is the ease of quantification of phospholipids. The applicability of the methods was tested on natural extracts of fish brain and cabbage stem.     

Case Study in Engineering History Education: Robert Stephenson’s “Last Great Work”—The Victoria Bridge in Montréal

The Victoria Bridge across the St. Lawrence River at Montréal is one of the great engineering achievements of the 19th century. At the time of its construction it was the largest bridge project in the world. It was also the last major project of the last of the “legendary” engineering figures of the “Victorian” era of engineering, Robert Stephenson. There were many doubters as to the ability of the engineers of the day to construct a project of this size given the physical conditions of the site. The story of the construction of the Victoria Bridge is one that combines business imperatives, engineering design skills, and construction ingenuity with the enormous challenges presented by one of the world’s great, fast flowing rivers and with the severity of Canadian winters and the massive “ice shoves” that occur as a result. Following its completion controversy raged as to who deserved the most credit for the conception and design of the bridge. The bridge was constructed between 1854 and 1860 and was formally opened by the Prince of Wales in the summer of 1860. Starting in 1897, the original Tubular Superstructure was replaced by pin-connected through trusses designed to carry two rail tracks with a roadway and sidewalk cantilevered out on each side. The bridge was formally reopened on October 16, 1901 and renamed the “Victoria Jubilee Bridge.” It continues to serve rail and road traffic to the present day.