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A straightforward and inexpensive implementation of acoustic impulse response measurement is described utilizing the signal processing technique of coherent averaging. The technique is capable of high signal-to-noise measurements with personal computer data acquisition equipment, an amplifier/speaker, and a high quality microphone. When coupled with simple waveguide test systems fabricated from commercial PVC plumbing pipe, impulse response measurement has proven to be ideal for undergraduate research projects-often of publishable quality-or for advanced laboratory experiments. The technique provides important learning objectives for science or engineering students in areas such as interfacing and computer control of experiments; analog-to-digital conversion and sampling; time and frequency analysis using Fourier transforms; signal processing; and insight into a variety of current research areas such as acoustic bandgap materials, acoustic metamaterials, and fast and slow wave manipulation.

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A considerable amount of information has been generated on the feeding value and impact of corn dried distillers' grains with solubles (DDGS) on meat quality, whereas little is known about the effects of wheat DDGS on meat quality, and no direct comparison of these two sources of DDGS has been completed. The current study was conducted to examine the objective and subjective carcass and meat quality traits of cattle fed diets containing corn or wheat (20% or 40%) DDGS (DM basis) as compared to a standard barley-based finishing diet (control). In general, meat obtained from animals fed the barley-based control diet was slightly darker in colour (lower chroma and hue at 24 h, P<0.01) and less tender (highest proportion of tough shears at 2 d and lowest proportion of tender shears at 20 d). Meat from corn DDGS was rated as more tender and palatable than control samples (P<0.05), and 20% corn samples were rated better for beef flavour intensity (P<0.01) and desirability (P<0.05) than 40% corn DDGS samples. In contrast, meat from steers fed wheat DDGS showed intermediate characteristics between steers fed control and corn DDGS diets. Hence, feeding wheat DDGS had no negative effects, and feeding corn DDGS had some positive effects on meat quality characteristics of beef.

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This study was undertaken to assess the effect of various levels of intramuscular fat (IMF: <1%, 1.0-1.49%, 1.5-1.99%, 2.0-2.49% and 2.5-3.0%) produced from Canadian pigs on the eating attributes of pork loin. Sensory and instrumental eating attributes were determined on 85 pork loins (m. longissimus lumborum and thoracis). The following correlations were found between IMF and eating attributes: softness, -0.32 (P<0.01); initial tenderness, -0.31 (P<0.01); chewiness, -0.27 (P<0.01); rate of breakdown, -0.20 (P=0.07); juiciness, 0.17 (P>0.05); flavour intensity, 0.24 (P=0.02); off-flavour, 0.13 (P>0.05); mouth coating, 0.13 (P>0.05); amount of perceptible connective tissue, -0.02 (P>0.05), and instrumental tenderness (Warner-Bratzler shear force), -0.41 (P<0.001). As tenderness is considered the most important attribute that determines overall acceptance of pork, the threshold level of IMF for ensuring a positive eating experience was identified as a function of the attributes describing tenderness. Increasing the level of IMF past 1.5% did not change (P<0.05) the panelists scores for softness and initial tenderness. Average shear force, an instrumental measure of tenderness, was higher (P<0.05) at less than 1% IMF but did not change past 1.0% IMF (P>0.05). It is proposed that the threshold level of IMF that will ensure a pleasing eating experience is 1.5% IMF.

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Three commercially available ultrasound instruments were evaluated using pigs representative of the Canadian pig population: CVT-2, UltraFom 300 and AutoFom. The reflectance probe HGP2 was utilized as the baseline instrument. Sampling was stratified by fat thickness. The original data set (n=236) was divided randomly into a calibration set (n=194 [85 barrows and 109 gilts]) to calibrate the instruments and a validation set (n=72[32 barrows and 40 gilts]) for validating the calibration models. For salable meat yield, RMSE values for the calibration models were: HGP2, 1.56; CVT-2, 1.57; UltraFom, 1.70; and AutoFom, 1.68. For lean (kg) in butt, picnic, loin and ham, and weight (kg) of the skinless, trimmed belly, RMSE for the calibration models was similar for all four instruments: respectively, 0.19-0.21, 0.21-0.23, 0.31-0.37, 0.35-0.40 and 0.35-0.36 kg. Validation results for predicting salable meat yield show that the improvement in precision and/or accuracy associated with the UltraFom 300 or AutoFom, over the baseline reflectance probe HGP2, was negligible whereas a definite advantage was observed for the CVT-2. However, validation results for predicting kg of lean in the primals did not show any clear advantage for the three commerciallly available ultrasound instruments over the baseline reflectance probe HGP2. Calibration and validation procedures showed that, if one was to base the assessment of these three ultrsound instruments uniquely on the precision and accuracy for predicting salable meat yield and/or kg of lean in the primals, any amelioration over the baseline reflectance probe HGP2 would have to be viewed as rather negligible; particularly for the UltraFom 300 or AutoFom.

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A study was undertaken to investigate the growth performance and carcass and meat quality of pigs (BW = 52 to 108 kg) fed oat-based (Avena sativa L.) diets containing four levels of mixed-linkage (1 --> 3), (1 --> 4)-beta-D-glucans. One hundred sixty pigs-80 barrows and 80 gilts (average starting BW = 52.7 kg)--were allocated to one of five diets: a wheat-barley-based control diet and four experimental diets. The groats of Marion, a covered oat, and OT789, a hulless oat, were used to formulate four isonitrogenous and isocaloric diets to achieve 4.1,3.3, 2.1, or 1.6% total /beta-glucans (as fed). Growth performance (daily gain and gain to feed ratio) was not affected (P > 0.05) by the different levels of beta-glucans. Carcass yield, although lower (P < or = 0.05) for pigs fed the control diet, was similar (P > 0.05) for pigs fed any of the experimental diets. Cutout yields were also alike (P > 0.05) across the five diets. Beta-glucan content had no effect (P > 0.05) on the longissimus muscle area, or, by and large, on the proportions of commercial cuts; the only exceptions were a commercial picnic from pigs fed the 2.1% diet lower (P < 0.05) relative to all other diets and a lower (P < 0.5) commercial loin from pigs fed diets 4.1 or 3.3% relative to the control diet. Furthermore, the relative proportions oftotal lean, total bone, and total dissectable fat in the four lean cuts (picnic, butt, loin, and ham) were not different (P > 0.05) among the five diets. For pigs fed 4.1% beta-glucans, the proportion of lean in each of the four major cuts was lower (P < 0.05). No differences (P > 0.05) associated with the level of beta-glucans were detected for either the initial or ultimate pH mean values, the subjective assessment of color or structure of the longissimus muscle, or the instrumentally measured color (L value). Similarly, drip loss was not influenced (P > 0.05) by the level of beta-glucans in the diets. Soluble protein did differ (P < 0.05) among the high- to low-beta-glucans diets. No differences (P > 0.05) associated with diets were found for fat hardness and shear values of grilled pork chops. Chemical fat of the longissimus muscle from pigs fed 4.1, 3.3, or 2.1% beta-glucans was lower (P < 0.05) compared to pigs fed the control or 1.6% beta-glucans diets. In summary, no evidence of detrimental effect of beta-glucans in oat-based diets, particularly at levels below 4%, was detected, lending support for the inclusion of oat into finisher diets.

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A Computer Vision System prototype for grading pork carcasses was developed at the Lacombe Research System. The system consists of two components: ultrasound imaging to scan a cross-section of the loin muscle and video imaging to capture two-dimensional (2D) and three-dimensional (3D) images of the carcass. For each of the 241 carcasses (114 barrows and 127 gilts), salable meat yield was determined from a full cutout. Linear, two- and three-dimensional, angular and curvature measurements and carcass volume were derived from each image. Muscle area and fat thickness (7 cm off the mid-line) measured by ultrasound at the next to last rib site, together with 2D and 3D measurements provided the most accurate model for estimating salable meat yield (R(2)=0.82 and RSD=1.68). Models incorporating fat thickness and muscle depth measured at the Canadian grading site (3/4 last rib, 7 cm off the mid-line) with the Destron PG-100 probe, had the lowest R(2) and highest residual standard deviation (RSD) values (R(2)=0.66 and RSD=2.15). Cross-validation demonstrated the reliability and stability of the models; hence conferring them good industry applicability. The Lacombe Computer Vision System prototype appears to offer a marked improvement over probes currently used by the Canadian pork industry.

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This work examines a simple one-dimensional acoustic band gap system made from a diameter-modulated waveguide. Experimental and theoretical results are presented on perfectly periodic waveguide arrays showing the presence of band gaps--frequency intervals in which the transmission of sound is forbidden. The introduction of defects in the perfect periodicity leads to narrow frequency transmission bands--defect states--within the forbidden band gaps. The circular cross-section waveguide system is straightforward to simulate theoretically and experimental results demonstrate good agreement with theory. The experimental transmission of the periodic waveguide arrays is measured using an impulse response technique.

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We report the cloning, expression and functional characterisation of a peroxidase belonging to the peroxiredoxin family from the potato cyst nematode Globodera rostochiensis, the first molecule of this type from any nematode parasitic on plants. The G. rostochiensis peroxiredoxin catalyses the breakdown of hydrogen peroxide, but not cumene or t-butyl hydroperoxide, in a trypanosomatid reducing system comprising trypanothione reductase, trypanothione and tryparedoxin. In common with its homologues from Onchocerca volvulus and Brugia malayi, the G. rostochiensis enzyme is present on the surface of invasive and post-infective juveniles despite the apparent lack of a cleavable N-terminal signal peptide. The possibility that the G. rostochiensis peroxiredoxin plays a role in protection of the parasite from plant defence responses is discussed.

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Secretions were induced from second (invasive) stage juveniles (J2s) of the potato cyst nematode Globodera rostochiensis by exposing them to 5-methoxy-N,N-dimethyl tryptamine oxalate (DMT). Secretions were collected from J2s in sufficient quantity to allow direct analysis. Gel electrophoresis followed by monochromatic silver staining demonstrated the presence of at least 10 proteins. The presence of several enzymes, including superoxide dismutase and proteases, was demonstrated using Western blots and activity assays. Antisera raised against the secretions recognized bands on Western blots consistent in molecular mass with those identified on silver stained gels. The antisera recognized structures implicated in the production of secretions including the subventral gland cells and surface of J2s.

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The surface coat of the infective larvae of the parasitic nematode Trichinella spiralis was characterized with respect to its biophysical properties, morphology and composition. Labelling of larvae with the fluorescent surface probe PKH26 was lost after activation (by incubation in mammalian medium containing trypsin and bile), or following pronase treatment. Electron microscopical examination revealed that pronase treatment resulted in the loss of an amorphous surface layer only, further demonstrating the specificity of PKH26 for the larval surface coat. Surface coat shedding was inhibited by sodium azide and carbonyl cyanide, or by incubation of larvae at 4 degrees C, suggesting the shedding process required metabolic energy. Pre-labelled, unactivated larvae demonstrated continuous slow surface coat shedding and could be re-labelled with PKH26, indicating that the shed coat is replaced in these parasites. However, pre-labelled larvae which were activated failed to re-label with the probe, suggesting that activation provides an irreversible trigger for surface changes. PKH26, therefore, is a useful marker for larval activation. Examination of the shed coat material by scanning electron microscopy revealed 2 types of morphologies; one comprising thin multilaminate sheets and the other of amorphous material with ridges producing a fingerprint-like motif. Western- and lectin-blotting of the shed coat material demonstrated 2 prominent entities; a 90 kDa glycoprotein, which bound Datura stramonium agglutinin and was resistant to N- and O-glycanase treatment and a 47-60 kDa set of protein(s). Analysis of the surface lipids by electrospray mass spectometry revealed the presence of lysophosphatidic acid (lysoPA, C14:2) and an unidentifiable component of 339.4 Da. These two lipids constituted 36.9% and 36% by mass of surface coat lipids respectively. The presence of lysoPA was confirmed by thin layer chromatography, which also detected phosphatidic acid (PA). The polar lipids detected in solvent rinses of intact parasites by electrospray mass spectrometry were PI (C48:4), PE (C40:4 and C38:4), PS (C40:4), lysoPC (C20:2 and C18:2) and lysoPA (C14:2). These observations are discussed with respect to the role of the surface coat and its shedding in the T. spiralis host-parasite relationship.

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The design of an alignment-detection system that uses off-axis diffractive elements and photodetectors is presented. The system was developed to detect the real-time misalignment of an array of optical beams as they pass through a microchannel relay. The design of this scheme is presented along with experimental results obtained from a prototype detection system.

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Electrophoresis of secretions collected from Globodera pallida revealed a smeared region between 25 and 50 kDa, and a single band of < 20 kDa. The secretions were used to raise an antiserum (LW1). Immunoblotting of parasite homogenates with LW1 differentiated G. pallida from its sibling species G. rostochiensis and revealed differences between different populations of G. pallida and G. rostochiensis. Indirect immunofluorescence studies with LW1 indicated that at least some of the secretions were surface localized and that antibody binding to the nematode surface was periodate sensitive. Periodate sensitivity indicated that these differences could be due to glycosylation differences. Glycosylation differences were also detected by blotting nematode homogenates with the lectin wheat germ agglutinin (WGA), WGA was also able to differentiate between G. rostochiensis which gave 2 bands at 130 kDa and 110 kDa, and G. pallida which produced 2 bands present at 120 kDa and 110 kDa. Further localization studies using immunoelectron microscopy demonstrated that antibody binding could be seen to secretions found in the pump chamber of the metacorpal bulb at the base of the stylet. From further specimens it could be observed that the contents of the subventral glands were heavily labelled, indicating that the material seen in the metacorpal bulb had originated from the subventral glands.

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The design, modeling, and experimental characterization of a microchannel-based free-space optical interconnect is described. The microchannel interconnect was used to implement a representative portion of an optical backplane that was based on field-effect transistor, self-electro-optic device smart-pixel transceivers. Telecentric relays were used to form the optical interconnect, and two modes based on two different optical window clusterings were implemented. The optical system design, including the optical geometry for different degrees of clustering of windows supported by a lenslet relay and the image mapping associated with a free-space optical system, is described. A comparison of the optical beam properties at the device planes, including the spot size and power uniformity of the spot array, as well as the effects of clipping and misalignment for the different operating modes, is presented. In addition, the effects of beam clipping and misalignment for the different operating modes is presented. We show that microchannel free-space optical interconnects based on a window-clustering scheme significantly increase the connection density. A connection density of 2222 connections/cm(2) was achieved for this prototype system with 2 x 2 window clustering.

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In the quest for plant regulatory sequences capable of driving nematode-triggered effector gene expression in feeding structures, we show that promoter tagging is a valuable tool. A large collection of transgenic Arabidopsis plants was generated. They were transformed with a beta-glucuronidase gene functioning as a promoter tag. Three T-DNA constructs, pGV1047, p delta gusBin19, and pMOG553, were used. Early responses to nematode invasion were of primary interest. Six lines exhibiting beta-glucuronidase activity in syncytia induced by the beet cyst nematode were studied. Reporter gene activation was also identified in galls induced by root knot and ectoparasitic nematodes. Time-course studies revealed that all six tags were differentially activated during the development of the feeding structure. T-DNA-flanking regions responsible for the observed responses after nematode infection were isolated and characterized for promoter activity.

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The design and implementation of a robust, scalable, and modular optical power supply spot-array generator for a modulator-based free-space optical backplane demonstrator is presented. Four arrays of 8 x 4 spots with 6.47-mum radii (at 1/e(2) points) pitched at 125 mum in the vertical direction and 250 mum in the horizontal were required to provide the light for the optical interconnect. Tight system tolerances demanded careful optical design, robust optomechanics, and effective alignment techniques. Issues such as spot-array generation, polarization, power efficiency, and power uniformity are discussed. Characterization results are presented.

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We describe a system demonstrator based on vertical-cavity surface-emitting lasers, metal-semiconductor-metal detectors, printed circuit board (PCB) level optoelectronic device packaging, a compact bulk optical relay, and novel barrel/PCB optomechanics. The entire system was constructed in a standard VME electrical backplane chassis and was capable of operating at >1.7 Gbit/s of aggregate data capacity. In addition to the component technologies developed, we describe operational testing and characterization of the demonstrator.

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A multi-subunit antigen (native M(r) > 200 kDa, reduced M(r) 97-100 kDa) has been identified in homogenates of Trichinella spiralis larvae using affinity-purified rabbit anti-keyhole limpet haemocyanin (KLH) antibodies and its cross-reactivity with KLH was confirmed by competition blotting. The antigen was not present at the larval surface but was exposed after treatment of the larvae with the detergent cetyltrimethyl ammonium bromide (CTAB) which removed the surface coat. This correlated with a significant decrease in insertion of the surface-restricted fluorescent lipid probe AF18, indicating that the surface coat must be lipidic in nature. Unlike KLH, the larval antigen blotted onto nitrocellulose was itself periodate insensitive. Periodate treatment of whole larvae, however, resulted in shedding of the surface, to which anti-KLH antibodies then bound intensely. Anti-KLH antibodies also recognized three (49, 55, 108 kDa) of the four most dominant antigens in excretory-secretory (ES) products of cultured larvae, whose excretion-secretion was increased with CTAB. The nature, location and function of the antigen is discussed.

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We detail the technical considerations for producing reconfigurable spot patterns with an integrated two-dimensional acousto-optic deflector. Practical limitations concerning the generation of high-density interconnect arrays are described. Experimental results for 13 × 13, 21 × 21, and 50 × 50 spot arrays are presented.