Letters to the Editor

Abstract

The principles of art criticism introduced by Professor Theodore M. Greene and elaborated by Professor Bernard C. Heyl have proven effective in engaging fourth-year architectural students in critical reading and analysis. By selecting numerous examples from writings on the life and work of Francesco Borromini, a designer of interest to most architectural students, different critical perspectives and various ways of structuring an argument and proving a point are demonstrated, leading students to grasp the difference between subjective opinion and criticism based upon more objective criteria. The essay explains Greene's classifications and the assignments created to introduce skills for academic research and evaluation.     

N‐3 enrichment of pork with fishmeal: Effects on production and consumer acceptability

This study aimed to develop pork products of acceptable organoleptic quality enriched with long‐chain n‐3 polyunsaturated fatty acids (LC n‐3 PUFA). Female pigs were fed a finisher diet containing 15% PorcOmega? tuna fishmeal or a commercial diet. Pigs and rations were weighed weekly. The feed conversion ratio was significantly lower in pigs fed fishmeal than in controls (2.61 ± 0.01 versus 2.96 ± 0.06, p <0.05). After 6 weeks, the pigs were butchered and the fatty acid contents of selected pork products were analyzed by gas chromatography. Shelf life was tested by thiobarbituric acid‐reactive substances (TBARS), initially and after 5 days of cold storage, and sensory qualities were evaluated after cooking. LC n‐3 PUFA contents of pork products from pigs fed fishmeal were higher than in controls (steak 300%, stir‐fry 250%, diced 520%, mince 480%, sausage 360%; p <0.05 in all cases). There were no differences between n‐3‐enriched and regular pork in either TBARS content of stored raw products or sensory characteristics after cooking. Incorporating fishmeal in the finisher diet resulted in greater feed efficiency and production of nutritionally enhanced pork products with organoleptic profiles and stability comparable to those of regular pork.     

Electrospun vascular graft properties following femtosecond laser ablation

For polymers in tissue engineering to reach their full potential, the three‐dimensional integration of cells with scaffolds must become more complex. In vascular grafts this is particularly challenging as specific physical property requirements must be met. We apply a combination of polymer processing techniques—electrospinning and femtosecond laser ablation—to produce microchannels inside the walls of electrospun tubes providing for spatially‐controlled cell seeding. To determine if such a scaffold can provide the desired physical properties, a greater understanding of the relationship between manufacturing and mechanics is needed. As the strength of these scaffolds is an important functional component, the relative properties of single, bi‐ and tri‐layer combinations produced using different solvents were compared. The effect of fiber layer thickness was also investigated. The thickness of the hexafluorisopropanol‐derived layer dominated the overall scaffold properties regardless of the nature of the other two layers. Although laser‐machined microchannels had substantial effects on single layer and some of the bilayers, in the “final” trilayer scaffold, little effect on mechanical properties was observed. The concept of “vascular wall engineering” could successfully produce trilayer composite scaffolds that maintain the targeted mechanical properties while allowing intricate, three‐dimensional cell seeding. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Disinfecting the Coquitlam Water Supply: Ozone and UV Disinfection

The Greater Vancouver Water District (GVWD) is upgrading its unfiltered Coquitlam water treatment system to meet the updated Health Canada guidelines for providing 3-log reduction or inactivation of Cryptosporidium and Giardia. The existing Coquitlam system, which is designed for peak flows of 1200 ML/d (317 mgd), includes an ozonation facility providing 3 log Giardia inactivation, and a chlorination/corrosion control facility. To meet Health Canada guidelines, a UV disinfection facility will be constructed, which will provide 3-log inactivation of Cryptosporidium and Giardia, and the ozone dosage will be increased to reduce THM and HAA precursors as well as improve UV transmittance. This paper will focus on the conceptual design of the Coquitlam system and the preliminary bench-scale studies that were completed for GVWD as part of the predesign phase of the project.     

Development of Transient Recombinant Expression and Affinity Chromatography Systems for Human Fibrinogen

Fibrin forms the structural scaffold of blood clots and has great potential for biomaterial applications. Creating recombinant expression systems of fibrinogen, fibrin’s soluble precursor, would advance the ability to construct mutational libraries that would enable structure–function studies of fibrinogen and expand the utility of fibrin as a biomaterial. Despite these needs, recombinant fibrinogen expression systems, thus far, have relied on the time-consuming creation of stable cell lines. Here we present tests of a transient fibrinogen expression system that can rapidly generate yields of 8–12 mg/L using suspension HEK Expi293^TM cells. We report results from two different plasmid systems encoding the fibrinogen cDNAs and two different transfection reagents. In addition, we describe a novel, affinity-based approach to purifying fibrinogen from complex media such as human plasma. We show that using a high-affinity peptide which mimics fibrin’s knob ‘A’ sequence enables the purification of 50–75% of fibrinogen present in plasma. Having robust expression and purification systems of fibrinogen will enable future studies of basic fibrin(ogen) biology, while paving the way for the ubiquitous use of fibrin as a biomaterial.     

Chewing gum affects smoking topography.

In a previous study, Wrigley's chewing gum was shown to reduce cravings to smoke and nicotine withdrawal when smokers were not allowed access to cigarettes. The present study expanded these findings by examining smoking behavior of 20 dependent cigarette smokers who were allowed free access to cigarettes throughout the study session but were encouraged and rewarded not to smoke. Each experimental session consisted of the participant watching a movie, then waiting an additional 30 min. Half of the participants were assigned to a gum condition in which they were asked to chew at least one piece of gum and had free access to chewing gum throughout the experimental session; half were assigned to a no-gum control. Results from this study indicate that when gum was present, participants took significantly fewer puffs and abstained for a longer period of time until their first cigarette. These results suggest that chewing gum may facilitate quit attempts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Moral hypocrisy: Appearing moral to oneself without being so.

How can people appear moral to themselves when they fail to act morally? Two self-deception strategies were considered: (a) misperceive one's behavior as moral and (b) avoid comparing one's behavior with moral standards. In Studies 1 and 2 the authors documented the importance of the 2nd strategy but not the 1st. Among participants who flipped a coin to assign themselves and another participant "fairly" to tasks, even a clearly labeled coin that prevented misperception did not produce a fair result (Study 1). Inducing behavior–standard comparison through self-awareness did (Study 2). Study 3 qualified the self-awareness effect: When moral standards were not salient before acting, self-awareness no longer increased alignment of behavior with standards. Instead, it increased alignment of standards with behavior and produced less moral action. Overall, results showed 3 different faces of moral hypocrisy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Partial (13)C and (15)N chemical-shift assignments of the disulfide-bond-forming enzyme DsbB by 3D magic-angle spinning NMR spectroscopy

DsbB is a 20 kDa Escherichia coli inner-membrane protein that catalyzes disulfide-bond formation in periplasmic proteins. We report highly resolved, multidimensional magic-angle spinning NMR spectra at 750 MHz (1)H frequency, which enable partial (13)C and (15)N chemical-shift assignments of the signals. The narrow line widths observed indicate excellent microscopic order of the protein sample, suitable for full structure determination by solid-state NMR. Experiments were performed exclusively on uniformly (13)C,(15)N-labeled DsbB. Chemical-shift-correlation experiments based on dipolar transfer yielded strong signals in the 3D spectra, many of which have been site-specifically assigned to the four transmembrane helices of DsbB. Significant numbers of additional residues have been assigned to stretches of amino acids, although not yet placed in the amino acid sequence. We also report the temperature dependence of signal intensities from -50 degrees C to 0 degrees C, a range over which samples of DsbB are highly stable. Structural and dynamic information derived from SSNMR studies can give insight into DsbB in a state that so far has not been successfully crystallized.     

Ubiquitin folds through a highly polarized transition state

The small alpha/beta protein ubiquitin has been used as a model system for experimental and computational studies on protein folding for many years. Here, we present a comprehensive phi-value analysis and characterize the structure and energetics of the transition state ensemble (TSE). Twenty-seven non-disruptive mutations are made throughout the structure and a range of phi-values from zero to one are observed. The values cluster such that medium and high values and found only in the N-terminal region of the protein, whilst the C-terminal region has consistently low phi-values. In the TSE, the main alpha-helix appears to be fully formed (two phi-values which specifically probe helical structure are one) and the helix is stabilized by packing against the first beta-turn, which is partially structured. In striking comparison, the phi-values in the C-terminal region are all very low, suggesting that this region of the protein is largely unstructured in the TSE. Data are consistent with a nucleation-condensation mechanism in which there is a highly polarized folding nucleus comprising the first beta-hairpin and the alpha-helix. Data presented from the protein engineering study and phi-value analysis are compared with results from other experimental studies and also computational studies.     

The influence of latitude on the concentration of vitamin D3 and 25-hydroxy-vitamin D3 in Australian red meat

There is little information on the vitamin D content of Australian red meat or on the possible influence of latitude on this content. To determine the content of vitamin D₃ and 25-hydroxy-vitamin D₃ (25OHD₃), lamb and beef were analysed from 34° S with LC–IT-MS. To investigate the possible influence of latitude on vitamin D in meat, the lean meat and fat from five cuts of beef were analysed from 17° S and 41° S. Lamb contained 0.10 μg vitamin D₃/100 g and 0.20 μg 25OHD₃/100 g lean meat, while beef contained 0.12 μg vitamin D₃ and 0.27 μg 25OHD₃/100 g (lean meat). Latitude had no effect on the vitamin D₃ (P = 0.21) or 25OHD₃ (P = 0.29) content of lean beef, but fat from cattle in the 17° S latitude group contained significantly higher (P < 0.01) concentrations of vitamin D₃ than fat from the 41° S group of cattle.