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Experiments were conducted to study the effect subtherapeutic levels of dietary antibiotic supplementation on the growth, intestinal characteristics and bacterial populations of chicks reared on "dirty" versus "clean" water. the lack of growth response to antibiotics in a Results showed that growth response to penicillin was independent of water treatment and the magnitude of growth response ranged from 0.9 to 18.3% levels. Bursal weights were significantly increased (P

Three experiments were conducted to investigate the effects of polyurethane coated urea on in vitro ruminal fermentation, ammonia release dynamics and lactating performance of Holstein dairy cows fed a steam-flaked corn-based diet. In Exp. 1, a dual-flow continuous culture was run to investigate the effect of polyurethane coated urea on nutrient digestibility, rumen fermentation parameters and microbial efficiency. Three treatment diets with isonitrogenous contents (13.0% CP) were prepared: i) feed-grade urea (FGU) diet; ii) polyurethane coated urea (PCU) diet; and iii) isolated soy protein (ISP) diet. Each of the diets consisted of 40% steam-flaked corn meal, 58.5% forages and 1.5% different sources of nitrogen. PCU and FGU diets had significantly lower digestibility of NDF and ADF (p

The Atomic Force Microscope (AFM) has become a powerful apparatus for performing real-time, quantitative force measurements between materials. Recently the AFM has been used to measure adhesive interactions between probes placed on the AFM cantilever and sample surfaces. This article reviews progress in this area of adhesion measurement, and describes a new technique (Jump Mode) for obtaining adhesion maps of surfaces. Jump mode has the advantage of producing fast, quantitative adhesion maps with minimal memory usage.

The force needed to remove micrometer-size polystyrene particles from elastomeric substrates having Young's moduli of 3.8 and 320 MPa was measured using atomic force techniques. It was found that the removal force was approximately an order of magnitude less for the more rigid substrate than for the more compliant substrate. In both cases the removal force was independent of applied load. However, when the more compliant material was overcoated with the stiffer material, the particle removal force was found to increase with increasing pressure, with the limit at low pressure commensurate with the removal force observed for the stiffer substrate and commensurate with the more compliant material at higher pressures. The results are interpreted in terms of the penetration depth of particle asperities into the substrates.

Intestinal myoelectric patterns in rats are altered after chronic luminal infection with the tapeworm Hymenolepis diminuta. This study evaluates whether these altered patterns were associated with changes in intestinal fluid transit and endogenous enteric microbe levels. Luminal transit, measured throughout the small intestine during the interdigestive state, was significantly decreased during tapeworm infection. Reduced transit was regional, occurring in the same location as that of the tapeworm and maximal myoelectric alterations. In other experimental systems, aerobic and anaerobic bacterial overgrowth is associated with decreased transit; however, reduced transit during tapeworm infection was unexpectedly associated with decreased numbers of aerobic bacteria, whereas anaerobic bacterial populations remained unchanged. The lack of overgrowing endogenous microflora suggests that overgrowth is not responsible for tapeworm-stimulated alterations in host myoelectric patterns. We speculate that a tapeworm secretion could be responsible for both transit and motility changes while delayed intestinal transit could prevent tapeworm expulsion, aid the tapeworms' migration, and contribute to the digestion and absorption of nutrients by hosts and/or parasites.

A transform is described for analyzing scanning-probe-microscope images. This radial-histogram transform is shown to contain useful information for ascertaining the structure of an object in a scanning-probemicroscope image. The radial-histogram transform also allows quantitative assessment of tip dilation effects. The utility of the transform is illustrated by analyzing a noncontact atomic force microscope image of a nanometer size Au cluster supported on a mica substrate. Using the radial-histogram transform, detailed information about the faceting, structure, and orientation of the supported nanometer-size cluster is obtained. @S0163-1829~96!02819-7#

The surface force interactions between individual 8 μm diameter spheres and atomically flat substrates have been investigated using atomic force techniques. The lift-off force of glass, polystyrene, and tin particles from atomically smooth mica and highly oriented pyrolitic graphite substrates was determined as a function of the applied loading force in an inert nitrogen environment. While the relative magnitudes of the measured lift-off force were found to scale as expected between the various systems studied, the absolute values were a factor of ∼50 smaller than expected from the Johnson, Kendall, and Roberts theory. The surface topography of representative spheres was characterized with atomic force microscopy, allowing a quantitative assessment of the role that surface roughness plays in the adhesion of micrometer-size particles to substrates. Taking into account the radius of curvature of the asperities measured from the atomic force scans, agreement between the measured and theoretical estimates for...

We have analyzed the electron transport processes in Al/AlOx/Al junctions. The samples were produced by glow-discharge-assisted oxidation of the bottom electrode. The nonlinear I–V curves of 17 samples were measured at room temperature, being very well fitted using the Simmons’ equation with the insulating barrier thickness, barrier height, and the junction area as free parameters. An exponential growth of the area normalized electrical resistance with thickness is obtained, using just values from I–V curve simulations. The effective tunneling area corresponding to the “hot spots” can be quantified and is five orders of magnitude smaller than the physical area in the studied samples.

The ability to perform atomic force and transmission electron microscopy on nanoscale Au clusters supported on the identical α-Al2O3 substrate has been demonstrated. Non-contact atomic force and transmission electron microscope images were used, in a complimentary manner, to determine: (i) the nanoscale structure of the α-Al2O3 substrate, (ii) the size distributions of cluster heights (AFM) and diameters (TEM) on α-Al2O3, (iii) the fraction of Au clusters imaged on different atomically-smooth substrates using non-contact AFM, and (iv) the surface induced deformation of Au clusters on α-Al2O3, MoS2 and HOPG substrates. From these data, information about supported cluster shape and cluster-substrate interactions for these three substrates was obtained.

The surface force interactions between a single micrometer-size polystyrene sphere and a p-type silicon substrate were investigated using atomic force microscope techniques. The force of removal and the degree of deformation of the particle determined as a function of the applied loading force. The work of removal, estimated assuming a perfectly spherical particle and a smooth substrate, was also determined. The influence of surface contamination and the implications of the short contact times used in these experiments are discussed.

During marketing, cattle may be exposed to periods of water deprivation. The impact of water and feed access and health status on the physiological well-being and carcass characteristics of Holstein slaughter cows during preslaughter marketing was studied through analysis of serum components, BW loss percentage, and fresh meat composition. Ninety-one multiparous Holstein cows (609 ± 89 kg mean BW, 2.9 ± 0.5 mean BCS, varying stage of lactation) were purchased over 3 wk in 3 groups (n = 31, 29, and 31) at a terminal market in central Wisconsin. Each cow was screened to determine health status (sick or not sick) and randomly assigned to 1 of 3 water and feed withdrawal treatment pens (AL, ad libitum access to water for 36 h; 18H, 18 h of ad libitum access to water followed by 18 h of water withdrawal; 36H, 36 h of water withdrawal; all 3 treatments included 36 h of feed withdrawal) in a randomized complete block arrangement with repeated measures for serum components. Blood samples were collected by tail venipuncture at 0, 9, 18, 27, and 36 h of each treatment. Ambient temperatures were 1.9 ± 6.2°C during the trial period, which occurred over a 3-wk period in March and April 2007 near Arlington, WI. No difference (P0.05) was observed in mean serum cortisol in AL (18.41 ± 2.17 ng/mL) or 36H (22.98 ± 2.17 ng/mL). Mean serum glucose was greater (P0.05) in 36H pens (78.15 ± 0.77 mg/dL) than AL (75.91 ± 0.77 mg/dL). Mean serum creatinine was greater (P0.05) in 36H pens (0.71 ± 0.03 mg/dL) than AL (0.60 ± 0.03 mg/dL). The 36H pens also displayed increased (P0.05) serum albumin, anion gap, Ca, Cl, Na, cholesterol, and aspartate aminotransferase over AL. Greater (P0.05) mean percentage BW loss was observed in 36H pens (5.2 ± 0.6%) than AL (3.1 ± 0.6%). Mean muscle protein (%) was greater (P0.05) in 36H (22.2 ± 0.4%) than 18H (21.3 ± 0.4%). Mean muscle moisture (%) was greater (P0.05) in AL and 18H (75.3 ± 0.4% and 75.2 ± 0.4%) than 36H. Mean 24-h pH values were 5.92 (AL), 5.92 (18H), and 5.81 (36H; SE = 0.04) and were not different (P0.05). Observed pH and color values indicated a borderline dark-cutter state across all cattle in the study, regardless of water and feed access treatment. Based on these results, water and feed withdrawal in lairage should not exceed 18 h during the marketing of Holstein slaughter cows acclimated to springtime conditions to maintain BW, serum component concentrations, and fresh meat composition.

The surface topography of YBa2Cu3O7 thin films prepared by pulsed laser deposition is studied by atomic force microscopy and scanning tunneling microscopy. The possible contributions from observed structural features to the critical current density Jc are discussed. It is shown that the contribution of the screw dislocations associated with some structures can be either repulsive or attractive, depending on the dominant pinning mechanism. At low magnetic fields (to about 0.25 kOe) these dislocations can account for the observed critical current density values (Jc≳1011 A/m2) while for larger fields the higher‐density steplike growth structures can account for significant values of Jc. It is shown that the pinning strength associated with pinning at steps varies inversely with thickness.

The objective of this work was to compare feedlot performance, carcass characteristics, and beef sensory attributes from steers finished with diets based on corn, high-tannin sorghum (HTS), and a mix of both grains. Angus crossbred steers (n = 11 steers per treatment, initial BW = 404 +/- 18 kg) were finished on diets containing 765 g/kg of DM of corn, HTS, or a 1:1 mix of corn and HTS. Final BW (P0.01), ADG (P0.001), and G:F (P0.01) were reduced in steers fed HTS when compared with steers fed corn. Steers fed the mixed diet had greater G:F than the average between corn and HTS diets (P = 0.04), which indicated that mixing corn and HTS had positive associative effects. Estimated NE(m) of HTS was 1.91, and estimated NE(g) was 1.35 Mcal/kg of DM. Hot carcass weight (P0.01), trimmed carcass weight (P0.01), yield grade (P = 0.04), and 12th-rib fat thickness (P = 0.01) were less in steers fed HTS than in those fed corn. Estimated percentage of HCW as boneless, closely trimmed retail cuts was greater in steers fed HTS compared with those fed corn (P = 0.02) but, due to the decreased HCW, estimated amount of boneless, closely trimmed retail cuts was less in steers fed HTS than in those fed corn (P = 0.03). Steers fed HTS had greater pH on LM (P = 0.02) than steers fed corn, but the difference was small (5.42 +/- 0.02 vs. 5.36 +/- 0.02, respectively) and within the range of normal beef pH. Diet had no effect on Warner-Bratzler shear values (Por = 0.72). Multivariate ANOVA indicated a difference in sensory attributes of beef from corn and HTS steers (Wilks' Lambda, P = 0.04). When evaluating each sensory attribute independently, panelists found beef from steers fed HTS to be less juicy (P0.01), less tender (P = 0.03), and more cooked (P0.01) than beef from animals fed corn. Data from this study indicated that by using a 1:1 mix of HTS and corn it is possible to finish steers to similar BW and carcass quality as by using a corn-based diet. Also, total replacement of corn by HTS in the diets produced lighter and leaner animals. Total replacement of corn by HTS in the finishing diet changed beef sensory attributes, reducing the perception of beef tenderness and juiciness by panelists but without changing instrumental tenderness.

Oxidative processes deteriorate the quality of meat products. High tannin sorghums (HTS) contain flavonoid oligomers known as proanthocyanidins or condensed tannins. These compounds act as anti-oxidants in vitro, but their effectiveness in vivo remains unclear. We tested the hypothesis that moderate amounts of dietary HTS could reduce markers of oxidation on muscle of rats without having detrimental effects in growth. We used 2 groups of 38 male Sprague Dawley rats at 5 and 13 wk of age each. Each age group was fed 4 diets in a completely randomized design. The younger group was fed the experimental diets for 10 wk (10W); whereas the older group was fed for 2 wk (2W). The diets were modified from the NIH-07 diet and contained HTS and corn at ratios of 0:50 (S0, control), 20:30 (S20), 35:15 (S35), and 50:0 (S50) as a percentage of the diet. Growth and the efficiency of gain were assessed periodically measuring BW, ADFI, ADG, and G:F. Oxidation in muscle was measured in fresh tissue and after 6 d of aerobic-refrigerated storage. Muscles evaluated were LM and soleus (SM). Fresh liver was also evaluated. Thiobarbituric acid-reactive substances (TBARS) and carbonyl content were used as markers of lipid and protein oxidation, respectively. No differences in BW, ADFI, ADG, and G:F were observed in 2W rats. Greater (P0.05) ADFI and ADG were observed in 10W-S35 group between d 1 and 7 and greater BW (P = 0.049) was observed in group 10W-S35 at d 70 compared with 10W-S0. No differences were observed between S0 and any HTS diet in G:F in 10W and 2W rats. No differences in TBARS or carbonyls were observed in liver. No differences in TBARS were observed in fresh and aged LM and SM. When LM samples were aged for 6 d, decreased carbonyl contents (P0.01) were observed in 10W-S35 and 10W-S50 diets compared with 10W-S0. Reductions in carbonyls were also observed in aged SM between 2W-S50 and 2W-S0 (P = 0.013). We concluded that inclusion of 35% HTS in the diet increased intake and growth rate of young, fast-growing rats without changing the efficiency of gain. Feeding HTS reduced markers of protein oxidation in rat muscle after 6 d of refrigerated storage. If similar results are observed in animals such as swine or cattle, the use of HTS as animal feed should be reassessed.

An atomic force microscope tip is used as a vector positioner to manipulate nanometer‐size preformed Au clusters deposited on atomically smooth substrates. Using this technique, two‐dimensional cluster nanostructures can be assembled at room temperature.

An atomic force microscope has been used in the attractive (noncontact) force mode to image individual nanometer‐size Au clusters preformed in the gas phase and deposited on a variety of atomically flat substrates. Using this technique, it is possible to reliably image preformed clusters in their as‐deposited positions. This capability allows nanoindentation studies to measure the mechanical properties of individual nanometer‐size clusters supported on atomically flat substrates. We find that the elastic modulus of a 3.1‐nm Au cluster is 56−19+33 GPa. This should be compared to a bulk value of 80 GPa for polycrystalline Au and 120 GPa for crystalline Au in the [111] direction.

Vitamins E and C are important antioxidants in animals. Their antemortem activity continues to function in postmortem muscle (meat), where they have a critical role in maintaining quality in the food product. Dietary supplementation of vitamin E, and intravenous infusion of vitamin C immediately before harvest, are efficacious techniques for increasing the concentration of these vitamins in beef skeletal muscle. Meat with elevated levels of either and probably both of these antioxidant vitamins possesses greater stability of oxymyoglobin and lipid, which results in less discoloration and rancidity, respectively. A model is proposed for the redox relationships between myoglobin and phospholipid in beef with emphasis on vitamins E and C. Antemortem nutritional intervention appears to be a promising approach for improving the quality of fresh meat products subsequently obtained from livestock.

An atomic force microscope has been used in the attractive (noncontact) force mode to image individual nanometer-size Au clusters preformed in the gas phase and deposited on a wide variety of atomically flat substrates. Using this noncontact technique, it is possible to reliably image preformed clusters in their as-deposited positions. This capability allows nanoindentation studies to measure the mechanical properties of individual nanometer-size Au clusters supported on atomically flat substrates and permits a measure of the deformation of a nanometer-size cluster as a function of the applied load. Applying a compression model to the deformed clusters, an elastic modulus roughly 2/3 that of bulk Au is obtained for annealed clusters with sizes between 3 and 18 nm. If the clusters are unannealed, a significantly smaller elastic modulus is observed (approximately 1/6 that of bulk Au). As the applied load increases beyond \ensuremath{\sim}20 nN, the data suggest that the yield point of an annealed Au cluster can be exceeded and the atomic force microscope tip can fracture the cluster.

An atomic force microscope has been used in the attractive (noncontact) force mode to image individual nanometer-size Au clusters preformed in the gas phase and deposited on a wide variety of atomically flat substrates. Contact imaging modes are shown to provide sufficient lateral forces to dislodge the clusters. Using a noncontact technique, it is possible to reliably image preformed clusters in their as-deposited positions. This capability allows nanoindentation studies to measure the mechanical properties of individual nanometer-size Au clusters supported on highly oriented pyrolitic graphite and permits a measure of the deformation of a nanometer-size cluster as a function of the applied load.

Nanoindentation experiments on high quality Au films were performed in vacuum using an atomic force microscope. In these experiments, elastic behavior was observed until loading forces greater than ∼ 20 nN were applied. For loads larger than this, systematic changes in the jump-to-contact, loading/unloading and lift-off regions of the data occur. These observations are consistent with a transition from elastic to inelastic behavior during indentation.

We studied the dielectric breakdown in tunnelling barriers produced by plasma-assisted oxidation of an aluminium surface. The barrier mean height, thickness and the effective tunnelling area were extracted from current versus voltage curves measured at room temperature. The effective tunnelling area ranged from 10−10 to 10−5 cm2, corresponding to less than 1% of the geometrical surface of the samples. The estimated electrical field to breakdown agreed with predictions from thermochemical models, and decreased exponentially with the effective tunnelling area.

The purpose of this study was to examine the relationship between the initial intramedullary hemorrhage, as seen by magnetic resonance imaging (MRI), and the neurologic deficit and eventual neurologic outcome of acute cervical spinal cord injured subjects. MRI and motor assessments were performed on 24 subjects with motor complete (Frankel AB) and incomplete (Frankel CD) injuries. Recovery was determined by evaluating an initial and a final motor power following spinal cord injury (SCI), as defined by the manual muscle test (grade 1-5) and motor index score (MIS). Results showed that all 15 subjects having hemorrhage had motor complete injuries (Frankel AB). Sixteen percent of the muscles in the upper extremities and 3% of the muscles in the lower extremities in these 15 subjects improved to a grade ofor = 3/5 at the final evaluation post-SCI. In comparison, of the nine subjects not having hemorrhage, eight had motor incomplete injuries (Frankel CD) and had 73% and 74% of muscles improving in the upper and lower extremities, respectively. In addition, a change in MIS from initial to final evaluations showed a significant difference between subjects with hemorrhage and subjects without hemorrhage (upper extremities: p = .002 and lower extremities: p = .0001). In conclusion, the initial MR image and neurologic assessment correlated with motor power recovery.

Effects of dietary supplementation and postmortem addition of vitamin E on pigment and lipid stability in raw ground beef were examined in this study. Six Holstein steers were fed a control diet for 232 or 252 d and six Holstein steers were supplemented with 1,500 IU of vitamin E per animal daily for 232 or 252 d. Three aliquots of ground beef from each longissimus lumborum were allotted to the following postmortem treatments: no addition (NO), white mineral oil (OIL), and white mineral oil containing sufficient D-alpha-tocopherol to equal the mean difference of alpha-tocopherol concentration between beef from supplemented and control steers (OIL + E). Metmyoglobin percentages and 2-thiobarbituric acid reactive substances values were determined at d 1, 3, 5, 7, and 9 after postmortem treatment. Dietary vitamin E supplementation delayed metmyoglobin increase and highly suppressed lipid oxidation in ground beef during 9 d of display compared with the control. The postmortem addition of vitamin E (OIL + E) was slightly effective in retarding the oxidation of pigment and lipid, especially compared with the OIL treatments. Endogenous vitamin E improved pigment and lipid stability much better than exogenous vitamin E.

The efficacy of chlorine dioxide (ClO2) as an alternative sanitizing agent for hatching eggs was investigated because of the health concerns about formaldehyde fumigation. Hatchability of chicken eggs was reduced when the eggs were dipped in the ClO2 solutions for more than 5 minutes or in concentrations greater than 100 ppm Cl. However, treating hatching eggs with a ClO2 foam or fumigating with formaldehyde had no adverse effect on hatchability compared with untreated control eggs. Sanitizing soiled duck eggs with ClO2 foam improved hatchability by more than 10% and hatch by more than 6% compared with untreated eggs (P less than 0.05). A novel method for assessing bactericidal potential of egg-sanitizing agents was developed. Using this technique, both chlorine dioxide foam and formaldehyde fumigation reduced the number of egg-contaminant bacteria inoculated on sterile chicken eggs compared with the number of bacteria on untreated eggs (P less than 0.05). These findings suggest that sanitizing hatching eggs with ClO2 foam may be a viable alternative to fumigating with formaldehyde.

We have made spin‐valve structures of Permalloy/Cu/Co by sputtering or electron‐beam deposition onto the antiferromagnetic oxide NiO. The oxides were made either by deposition of the metals and subsequent oxidation or by growing them in situ using reactive sputtering. The magnetic properties of the giant magnetoresistancestructures were studied by magnetoresistance, vibrating sample magnetometry, and ferromagnetic resonance methods. The oxides were characterized by x‐ray diffraction and atomic force microscopy. We studied surface roughness and structure as functions of thickness and oxidation temperature and correlated the oxide properties with the magnetic performance. We found that the metal layer roughened during the postdeposition oxidation process and that the resulting oxide layers were very effective in pinning the direction of the magnetic moment of adjacent metal films. Coercive fields over 500 Oe were obtained for Co overlayers on NiO films but the exchange bias field was generally less than 100 Oe and was not strongly dependent on the roughness. The beneficial effects of this strong pinning were offset to some degree by higher switching fields required in spin‐valve structuresdeposited over the Co. We also made reactively sputtered oxide antiferromagneticfilms which had smoother surfaces than those made by postdeposition oxidation.

Four commercial media marketed for the detection and enumeration of Clostridium perfringens were found to adequately support the growth of a pure culture (ATCC 13124) of this species but enumeration of colony-forming units was difficult on Clostrisel and lecithin-lactose-agar base (LLA) media. Colonies of C. perfringens on LLA had typical opalescent zones, a distinctive feature that can aid in presumptive identification. Colonies on sulfite-polymyxin-sulfadiazone and tryptose-sulfite-neomycin (TSN) agar media were morphologically similar but black colonies were observed on TSN incubated at 46 C. Extreme difficulty was encountered in enumerating enteric bacteria from the chick intestine on Clostrisel medium because of the pinpoint size of the colonies and on LLA because of the opacity of the medium. Morphological characteristics of bacteria picked from colonies which formed after these media had been inoculated with chick intestinal contents were in sharp contrast to those of the pure culture of C. perfringens. Numbers of colony-forming units were higher than documented levels of C. perfringens in the intestine of chicks. These observations led to the conclusion that these formulations are inadequate for the selective cultivation and enumeration of this bacterial species from the intestine of healthy chicks, unless used in combination with further tests for specific identification.

Pigment and lipid oxidation was investigated in fresh ground sirloin from control and vitamin E-supplemented (370 I.U./head/day) Holstein steers. Alpha-tocopherol levels were higher (P

Cross-reactivity among four species of ruminal bacteria was examined by using egg yolk antibodies from immunized Leghorn laying hens and an enzyme-linked-immunosorbent assay. The effects of the four species on the hens were compared on various days postimmunization. Hens injected with the same bacterial species had similar apparent antibody levels over the entire postimmunization period, but only Bacteroides ruminicola B1(4) and Selenomonas ruminantium D antigens elicited early increases in apparent antibody levels during weeks 2 and 3. Antibody cross-reactivity was greatly reduced by week 2, except for antibodies against Streptococcus bovis JB1.

A technique has been developed that allows a real-time measurement of the lift-off force required to remove a scanning force microscope tip from a substrate. Both topography and adhesion maps are obtained simultaneously, allowing the correlation between topography and adhesion properties to be studied. Quantitative values of important adhesion parameters can be extracted from these data. A number of examples are given which illustrate the utility of this technique.