Information technology and regulatory reformThe interorganisational effects of a technological innovation

This paper examines whether information technology can play a strategic role in supporting regulatory reforms aimed at achieving voluntary cooperation with government regulation. Analysis of the case of electronic tax return lodgment in Australia suggests that the effects of IT are contextual, and identifies positive effects of the new IT system on voluntary cooperation. However, in this case, divergence between private and public interests and uncertainty and lack of participation in regulatory decision-making appear to restrict the development of voluntary cooperation as a primary basis for government regulation.     

Sanger DNA-sequencing reactions performed in a solid-phase nanoreactor directly coupled to capillary gel electrophoresis

A miniaturized, solid-phase nanoreactor was developed to prepare Sanger DNA-sequencing ladders which was directly interfaced to a capillary gel electrophoresis system. A biotinylated fragment of the rat brain actin gene (1 kbp) was amplified by PCR and attached to the interior wall of an (aminoalkyl)silane-derivatized fused-silica capillary tube via a biotin/streptavidin/biotin linkage. Coverage of the capillary wall with the biotinylated DNA averaged 77 +/- 10%. Stability of the anchored template under pressure (33 nL/s) and electroosmotic flows (11.3 nL/s) were favorable, requiring rinsing for > 150 h to reduce the surface coverage by only 50%. In addition, the immobilized template was stable toward temperatures required for preparing sequencing ladders, even under cycling conditions. Standard Sanger dideoxynucleotide termination performed in a large-volume (approximately 8 microL) solid-phase reactor using the thermally stable polymerase enzymes Taq and Vent and the polymerases T7 and Bst with off-line slab gel electrophoresis and autoradiographic detection indicated that acceptable fragment generation was achieved only in the case of the thermally stable polymerases. Banding was not apparent for T7 and Bst since all reagents were inserted into the column in a single plug at the beginning of the reaction. A small volume reactor (volume approximately 62 nL) was then used to perform DNA polymerase reactions and was coupled directly to a capillary gel column for separation. The capillary reactor was placed inside a thermocycler to control the temperature during chain extension and was directly connected to the gel column via zero dead volume fused-silica connectors. The complementary DNA fragments generated (C-track only) in the reactor were denatured using heat and directly injected onto the gel-filled capillary for size separation with detection accomplished using near-IR laser-induced fluorescence. Extension and single-base separation resolution of the C-track, which was directly injected onto the gel column, was estimated to be > 450 bases from the primer annealing site with plate numbers ranging from 1 x 10(6) to 2 x 10(6)/m.     

Distalless expression in crustaceans and the patterning of branched limbs

The ability of two-dimensional echocardiography to detect and to evaluate the extent of wall motion abnormalities is limited by the use of few selected, nonparallel, views of the whole left ventricle. This leads to an incomplete appreciation of the spatial relationships between various cardiac structures and inaccuracy in quantitative data as a result of using of geometric assumptions. Dynamic volume-rendered three-dimensional echocardiography has the ability to overcome the above limitations. In this article we review the use of volume-rendered three-dimensional echocardiography in the diagnosis and assessment of ischemic heart disease, including complications related to myocardial infarction.     

Melting of a DNA hairpin without hyperchromism

UV absorbance spectroscopy is the most common method for detecting nucleic acid structural transitions and obtaining thermodynamic parameters. UV-detected melting has been used to determine stabilities of nucleic acid hairpins, duplexes, triplexes, and higher order structures and to determine thermodynamic effects of unusual or modified bases and mismatched base-pairs. We report that in some cases UV absorbance spectroscopy is an inadequate analytical technique for these purposes. Some critical transitions are invisible to UV absorbance spectroscopy. For example, the conversion of dodecamer d(CGCAAATTCGCG) from hairpin to random coil is not accompanied by hyperchromism. Circular dichroism (CD) spectroscopy (263 nm) clearly detects two transitions for this dodecamer, each giving a pronounced change in ellipiticity. The concentration dependence of the low-temperature transition and the concentration independence of the high-temperature transition indicate that the predominant state converts from duplex to hairpin to random coil as the temperature increases. These assignments are confirmed by comparison to oligonucleotides of similar sequence that undergo a hairpin to coil transition only. In contrast to CD spectroscopy, UV absorbance spectroscopy shows only a single transition. The transition detected by UV absorbance spectroscopy corresponds to the low-temperature transition detected by CD. UV absorbance spectroscopy does not detect the second transition at any wavelength (from 218 to 310 nm) (by changes) in either absorbance or its derivative with temperature.     

Hyperphagia induced by hypoglycemia in rats is independent of leptin and hypothalamic neuropeptide Y (NPY)

Hypoglycemia causes hyperphagia and weight gain, through unknown peripheral and central signals. We investigated the effect of hypoglycemia on NPY and leptin expression and the ability of leptin to inhibit hypoglycemia-induced hyperphagia. Acute hypoglycemia (60 U/kg SC insulin; n = 8) increased food intake (p < 0.01) compared with controls (n = 8). Insulin- and leptin-treated rats (300 microg/kg IP leptin; n = 8) had reduced hyperphagia (p < 0.05 vs. controls; p < 0.05 vs. insulin alone) and a 15% fall in NPY mRNA levels compared with controls (p < 0.01). Chronic hypoglycemia, (20-60 U/kg/day insulin; n = 8) increased food intake compared with vehicle-treated controls (p < 0.01). Leptin and insulin administration (300 microg/kg/day IP leptin; n = 8) reduced hyperphagia (p < 0.01 vs. controls, p < 0.05 vs. insulin alone), and NPY mRNA fell by 18% vs. controls (p < 0.01). We conclude that hypoglycemia-induced hyperphagia is not mediated by either a fall in leptin or an increase in hypothalamic NPY mRNA. Leptin can inhibit feeding in hyperphagic hypoglycemic rats, and this may partly be attributable to its inhibition of the NPY neurons.     

Scanning alanine mutagenesis of the CDP-alcohol phosphotransferase motif of Saccharomyces cerevisiae cholinephosphotransferase

Cholinephosphotransferase (EC 2.7.8.2) catalyzes the formation of a phosphoester bond via the transfer of a phosphocholine moiety from CDP-choline to diacylglycerol forming phosphatidylcholine and releasing CMP. A motif, Asp113-Gly114-(X)2-Ala117-Arg118-(X)8-Gly127+ ++-(X)3-Asp131-(X)3-Asp135, located within the CDP-choline binding region of Saccharomyces cerevisiae cholinephosphotransferase (CPT1 ?/Author: Please confirm that a gene is meant here.) is also found in several other phospholipid synthesizing enzymes that catalyze the formation of a phosphoester bond utilizing a CDP-alcohol and a second alcohol as substrates. To determine if this motif is diagnostic of the above reaction type scanning alanine mutagenesis of the conserved residues within S. cerevisiae cholinephosphotransferase was performed. Enzyme activity was assessed in vitro using a mixed micelle enzyme assay and in vivo by determining the ability of the mutant enzymes to restore phosphatidylcholine synthesis from radiolabeled choline in an S. cerevisiae strain devoid of endogenous cholinephosphotransferase activity. Alanine mutants of Gly114, Gly127, Asp131, and Asp135 were inactive; mutants, Ala117 and Arg118 displayed reduced enzyme activity, and Asp113 displayed wild type activity. The analysis described is the first molecular characterization of a CDP-alcohol phosphotransferase motif and results predict a catalytic role utilizing a general base reaction proceeding through Asp131 or Asp135 via a direct nucleophilic attack of the hydroxyl of diacylglyerol on the phosphoester bond of CDP-choline that does not proceed via an enzyme bound intermediate. Residues Ala117 and Arg118 do not participate directly in catalysis but are likely involved in substrate binding or positioning with Arg118 predicted to associate with a phosphate moiety of CDP-choline.     

Personalizing 3D virtual fashion stores: Exploring modularity with a typology of atmospherics based on user input

This research develops a typology of atmospherics that contains user-identified modules and modular options for personalizing 3D virtual fashion stores. A content analysis of 46 focus group discussions (n = 170) was conducted to understand the user’s perspective for personalizing 3D virtual fashion store atmospherics. Based on three atmospheric categories (pathfinding assistant, environment, and the manner of product presentation), 17 modules and 207 modular options were identified for personalizing 3D virtual stores. This research pioneers the development of an atmospherics typology for personalizing 3D virtual shopping environments as a persuasive selling tool in the emerging field of 3D virtual reality (VR) retailing.     

Gaze tutor: A gaze-reactive intelligent tutoring system

We developed an intelligent tutoring system (ITS) that aims to promote engagement and learning by dynamically detecting and responding to students' boredom and disengagement. The tutor uses a commercial eye tracker to monitor a student's gaze patterns and identify when the student is bored, disengaged, or is zoning out. The tutor then attempts to reengage the student with dialog moves that direct the student to reorient his or her attentional patterns towards the animated pedagogical agent embodying the tutor. We evaluated the efficacy of the gaze-reactive tutor in promoting learning, motivation, and engagement in a controlled experiment where 48 students were tutored on four biology topics with both gaze-reactive and non-gaze-reactive (control condition) versions of the tutor. The results indicated that: (a) gaze-sensitive dialogs were successful in dynamically reorienting students’ attentional patterns to the important areas of the interface, (b) gaze-reactivity was effective in promoting learning gains for questions that required deep reasoning, (c) gaze-reactivity had minimal impact on students’ state motivation and on self-reported engagement, and (d) individual differences in scholastic aptitude moderated the impact of gaze-reactivity on overall learning gains. We discuss the implications of our findings, limitations, future work, and consider the possibility of using gaze-reactive ITSs in classrooms.     

Corrections for nonuniform sampling distortions in magnetic resonance imagery

A technique for estimating and correcting nonuniform sampling distortions in magnetic resonance imagery is presented. The technique consists of first estimating the sampling grid distortion using a parametric model, and then estimating the uniformly sampled data by interpolation on the nonuniform grid. Parameterized models for two particular sampling grid distortion are presented. Maximum likelihood and maximum a posteriori estimators are developed for these distortions. Using computer simulated data, these estimators are shown to perform well.     

Fourth International Conference on Durability of Building Materials and Components

RILEM Bulletin

Fourth International Conference on Durability of Building Materials and Components