Enhanced radiative strength in the quasicontinuum of 117Sn.

The radiative strength function of 117Sn has been measured up to the neutron separation energy using the (3He, 3He' gamma) reaction. An increase in the slope of the strength function around E gamma=4.5 MeV indicates the onset of a resonancelike structure, giving a significant enhancement of the radiative strength function compared to standard models in the energy region 4.5

Direct nn-Scattering Measurement With the Pulsed Reactor YAGUAR.

Although crucial for resolving the issue of charge symmetry in the nuclear force, direct measurement of nn-scattering by colliding free neutrons has never been performed. At present the Russian pulsed reactor YAGUAR is the best neutron source for performing such a measurement. It has a through channel where the neutron moderator is installed. The neutrons are counted by a neutron detector located 12 m from the reactor. In preliminary experiments an instantaneous value of 1.1 × 10(18)/cm(2)s was obtained for the thermal neutron flux density. The experiment will be performed by the DIANNA Collaboration as International Science & Technology Center (ISTC) project No. 2286.

Bounds on Time Reversal Violation From Polarized Neutron Capture With Unpolarized Targets.

We have analyzed constraints on parity-odd time-reversal noninvariant interactions derived from measurements of the energy dependence of parity-violating polarized neutron capture on unpolarized targets. As previous authors found, a perturbation in energy dependence due to a parity (P)-odd time (T)-odd interaction is present. However, the perturbation competes with T-even terms which can obscure the T-odd signature. We estimate the magnitudes of these competing terms and suggest strategies for a practicable experiment.

Large enhancement of radiative strength for soft transitions in the quasicontinuum.

Radiative strength functions (RSFs) for the (56,57)Fe nuclei below the separation energy are obtained from the 57Fe(3He,alphagamma)56Fe and 57Fe(3He,3He'gamma)57Fe reactions, respectively. An enhancement of more than a factor of 10 over common theoretical models of the soft (E(gamma) less than or approximately equal 2 MeV) RSF for transitions in the quasicontinuum (several MeV above the yrast line) is observed. Two-step cascade intensities with soft primary transitions from the 56Fe(n,2gamma)57Fe reaction confirm the enhancement.

Interferometer-controlled scanning transmission X-ray microscopes at the Advanced Light Source.

Two new soft X-ray scanning transmission microscopes located at the Advanced Light Source (ALS) have been designed, built and commissioned. Interferometer control implemented in both microscopes allows the precise measurement of the transverse position of the zone plate relative to the sample. Long-term positional stability and compensation for transverse displacement during translations of the zone plate have been achieved. The interferometer also provides low-distortion orthogonal x, y imaging. Two different control systems have been developed: a digital control system using standard VXI components at beamline 7.0, and a custom feedback system based on PC AT boards at beamline 5.3.2. Both microscopes are diffraction limited with the resolution set by the quality of the zone plates. Periodic features with 30 nm half period can be resolved with a zone plate that has a 40 nm outermost zone width. One microscope is operating at an undulator beamline (7.0), while the other is operating at a novel dedicated bending-magnet beamline (5.3.2), which is designed specifically to illuminate the microscope. The undulator beamline provides count rates of the order of tens of MHz at high-energy resolution with photon energies of up to about 1000 eV. Although the brightness of a bending-magnet source is about four orders of magnitude smaller than that of an undulator source, photon statistics limited operation with intensities in excess of 3 MHz has been achieved at high energy resolution and high spatial resolution. The design and performance of these microscopes are described.

Optimization of scanning transmission X-ray microscopy for the identification and quantitation of reinforcing particles in polyurethanes.

The morphology, size distributions, spatial distributions, and quantitative chemical compositions of co-polymer polyol-reinforcing particles in a polyurethane have been investigated with scanning transmission X-ray microscopy (STXM). A detailed discussion of microscope operating procedures is presented and ways to avoid potential artifacts are discussed. Images at selected photon energies in the C 1s, N 1s and O 1s regions allow unambiguous identification of styrene-acrylonitrile-based (SAN) copolymer and polyisocyanate polyaddition product-based (PIPA) reinforcing particles down to particle sizes at the limit of the spatial resolution (50 nm). Quantitative analysis of the chemical composition of individual reinforcing particles is achieved by fitting C 1s spectra to linear combinations of reference spectra. Regression analyses of sequences of images recorded through the chemically sensitive ranges of the C 1s, N 1s and O 1s spectra are used to generate quantitative compositional maps, which provide a fast and effective means of investigating compositional distributions over a large number of reinforcing particles. The size distribution of all particles determined by STXM is shown to be similar to that determined by TEM. The size distributions of each type of reinforcing particle, which differ considerably, were obtained by analysis of STXM images at chemically selective energies.

Net nutrient flux in visceral tissues of lambs fed diets differing in supplemental nitrogen source.

Eight multicatheterized wethers (35.9 +/- .8 kg BW) were used in a replicated 4 x 4 Latin square design to measure N retention and net uptake and release of plasma metabolites across the portal-drained viscera (PDV), hepatic (HEP), and total splanchnic (TS) tissues in response to changes in supplemental N source. Treatments selected to provide different amounts of undegradable intake protein (UIP) were urea, soybean meal (SBM), poultry by-product meal (PBM), and bloodmeal:corn gluten meal (BMCGM; 50:50 CP basis). Diets (urea, SBM, PBM, and BMCGM) contained 12.9, 13.8, 13.6, and 13.2% CP, respectively. Periods were 10 d, with total feces and urine collected on d 7 to 10 and blood sampled on d 10. Wethers were fed at 2% of BW in 12 daily portions. Nitrogen retention was 2.2, 3.3, 4.1, and 4.4 g/d for urea, SBM, PBM, and BMCGM, respectively. Urea had less (P < .01) N retention than SBM, PBM, and BMCGM; SBM had less N retention (P < .01) than PBM and BMCGM. Arterial, portal, and hepatic plasma flows were greater (P < .09) for SBM than for PBM and BMCGM (21 vs 16, 17; 84 vs 72, 72; 105 vs 87, 88 L/h). Portal plasma flow was greater (P < .10) for urea than for SBM, PBM, and BMCGM (85 vs 84, 72, 72 L/h). Portal-drained viscera and TS alpha-amino N (AAN) fluxes were less (P < .05) for PBM than for BMCGM (20.5 vs 26.6 and 7.2 vs 15.1 mmol/h), but TS AAN flux was less (P < .05) for urea than for SBM, PBM, and BMCGM (6.9 vs 16.9, 7.2, 15.1 mmol/h). Portal-drained viscera flux and HEP removal of NH3 N were greater (P < .001) for SBM than for PBM and BMCGM (27.7 vs 19.4, 20.6; -28.1 vs -20.0, -21.4 mmol/h). Gut use was less (P = .07) and HEP and TS fluxes of urea N were greater (P < .01) for SBM than for PBM and BMCGM (-4.92 vs -8.32, -7.93; 25.87 vs 16.54, 20.00; 20.95 vs 8.22, 12.07 mmol/h). These data suggest that PBM and BMCGM improved efficiency of N use compared with urea and SBM by reducing urinary N loss.

Nutritional evaluation of poultry by-product meal as a protein source for ruminants: small intestinal amino acid flow and disappearance in steers.

Six Angus steers (260+/-4 kg initial BW) fitted with ruminal, duodenal, and ileal cannulas were used in a 6 x 6 Latin square design to evaluate the effect of feeding poultry by-product meal (PBM) on small intestinal flow and disappearance of amino acids. The diets were provided at 2% of BW on a DM basis, formulated to contain 11.5% CP, and consisted of 49% corn silage, 36% cottonseed hulls, and 15% supplement on a DM basis. Supplements were formulated to contain 37% CP with sources of supplemental N being soybean meal (100% SBM) and 0, 25, 50, 75, and 100% PBM, with urea used to balance for N. Duodenal flow of all amino acids increased linearly (P < .07) as PBM increased in the diet and, except for His, increased (P < .09) for 100% PBM compared with 100% SBM. Similar results were observed for duodenal flow of nonbacterial amino acids, which linearly increased (P < .05) with PBM and were greater (P < .05) for 100% PBM than for 100% SBM. Soybean meal increased (P < .09) the duodenal flow of nonbacterial Lys compared with 0% PBM, and 0% PBM increased (P < .04) flow of Val, Ala, and Pro compared with 100% SBM. Duodenal bacterial essential, nonessential, and total amino acid flows were not affected (P > .80) by PBM; however, they were greater (P < .02) for 100% SBM than for 100% PBM. In addition, nonessential and total bacterial amino acid flows were increased (P < .06) for 100% SBM compared with 0% PBM. Small intestinal disappearance of Lys and Pro increased linearly (P < .09) as PBM increased, and 100% PBM increased (P < .07) disappearance of Arg and Ala compared with 100% SBM. Supplemental N source had no effect (P > .31) on apparent small intestinal disappearance of essential, nonessential, and total amino acids. These data suggest that when PBM, SBM, and urea were used as sources of supplemental N, the daily disappearance of amino acids from the small intestine of steer calves consuming a corn silage- and cottonseed hull-based diet was similar.

Nutritional evaluation of poultry by-product meal as a protein source for ruminants: effects on performance and nutrient flow and disappearance in steers.

We conducted three studies with steers to evaluate poultry by-product meal (PBM) as a supplemental N source for ruminants. An in situ study compared the solubility, degradation rate, and ruminal escape of PBM N with blood meal (BM), corn gluten meal (CGM), and soybean meal (SBM) N. Additionally, an 84-d growth study (n = 95, 228+/-5 kg BW) and a digestion trial (6 x 6 Latin square) were conducted. The basal diet for the growth and digestion studies consisted of 49% corn silage, 36% cottonseed hulls, and 15% supplement (DM basis). Sources of supplemental N (% of total supplemental N) were 100% SBM and 0, 25, 50, 75, and 100% PBM, with urea used to balance for N. In situ ruminal escape N (25.2, 55.3, 86.7, and 98.9% for SBM, PBM, CGM, and BM, respectively) was greater (P < .05) for PBM than for SBM; however, a greater (P < .05) proportion of BM and CGM N escaped ruminal degradation compared with PBM. Dry matter intake, ADG and gain/ feed increased linearly (P < .003) as PBM increased; however, no differences (P > .48) were observed in these variables for 100% PBM compared with 100% SBM. Duodenal N flow and small intestinal N disappearance increased linearly (P < .05) as PBM increased in the diet. Bacterial N flow to the small intestine was not affected (P > .19) by treatment; however, 100% SBM decreased (P < .04) bacterial CP synthesis (g bacterial N/kg OM disappearance from the stomach) compared with 0 and 100% PBM. In vivo ruminal escape N of PBM and SBM was 40.6 and 13.7%, respectively. Ruminal NH3 N decreased linearly (P < .001) as PBM increased. These data suggest that PBM can replace SBM as a source of supplemental N for steer calves that consume a diet based on corn silage and cottonseed hulls.

Comparison of two ammoniation procedures to reduce the toxicity of endophyte-infected tall fescue seed fed to rats.

To determine the effect of extending the duration of ammonia (2% dry matter basis) treatment from 1 to 5 wk on the toxicity of endophyte-infected tall fescue seed, 60 male Harlan Sprague-Dawley rats were randomly assigned to the following six treatments during a 28-d trial: endophyte-free (E-), endophyte-infected (E+), 1 wk ammoniated endophyte-free (1AE-), 1 wk ammoniated endophyte-infected (1AE+), 5 wk ammoniated endophyte-free (5AE-), and 5 wk ammoniated endophyte-infected (5AE+) tall fescue seed. The concentration of total pyrrolizidine alkaloids (N-acetyl and N-formyl loline) of E+ fescue was reduced from 4203 micrograms/g to 3009 and 2533 micrograms/g by the 1AE+ and 5AE+ treatments, respectively. Ergovaline was lowered from 3.77 to 1.57 micrograms/g by 1AE+ and eliminated by 5AE+. Endophyte-infected treatment groups had depressed (P < 0.0001) daily feed intakes (DFI), daily weight gains (DWG), feed efficiencies (G/F), primary antibody responses, and T cell and B cell mitogenic responses than endophyte-free treatment groups. Ammoniation of endophyte-infected fescue seed improved DFI and DWG (P < 0.0001) and G/F (P < 0.05); however, there was no difference in performance criteria between the 1-wk and 5-wk ammoniation treatments. Endophyte-induced depressions in immune function were not alleviated by ammoniation.

Ammoniation to reduce the toxicity of endophyte-infected tall fescue seed fed to rats.

To assess the efficacy of ammoniation in the detoxification of endophyte-infected tall fescue (Festuca arundinacea Schreb), 40 male Harlan Sprague-Dawley rats were randomly assigned to the following four treatments for 28 d: endophyte-free (E-), endophyte-infected (E+), ammoniated (2% dry matter basis, 7 d) endophyte-free (AE-), and ammoniated endophyte-infected (AE+) tall fescue seed. Total pyrrolizidine alkaloid (N-acetyl and N-formyl loline) and ergovaline contents of endophyte-infected fescue seed were reduced 24 and 54%, respectively, by ammoniation. Endophyte-infected treatment groups had lower (P < 0.01) daily feed intakes (DFI), daily weight gains (DWG), feed efficiencies, and primary serum hemagglutination titers to sheep red blood cell (SRBC) immunization than endophyte-free treatment groups. Performance parameters were higher (P < 0.01) for ammoniated diets in comparison to non-ammoniated diets; however, anti-SRBC titers were not significantly different. When compared to the E+ diet, the AE+ diet increased (P < 0.01) DFI (24%), DWG (41%) and feed efficiency (13%).

Ammoniation to reduce the toxicity of endophyte-infected tall fescue seed fed to rats.

To assess the efficacy of ammoniation in the detoxification of endophyte-infected tall fescue (Festuca arundinacea Schreb.), 40 male Harlan Sprague-Dawley rats were randomly assigned to the following four treatments for 28 d: endophyte-free (E-), endophyte-infected (E+), ammoniated (2% dry matter basis, 7 d) endophyte-free (AE-), and ammoniated endophyte-infected (AE+) tall fescue seed. Total pyrrolizidine alkaloid (N-acetyl and N-formyl loline) and ergovaline contents of endophyte-infected fescue seed were reduced 24 and 54%, respectively, by ammoniation. Endophyte-infected treatment groups had lower (P < 0.01) daily feed intakes (DFI), daily weight gains (DWG), feed effieiencies, and primary serum hemagglutination titers to sheep red blood cell (SRBC) immunization than endophyte-free treatment groups. Performance parameters were higher (P < 0.01) for ammoniated diets in comparison to non-ammoniated die [s; however, anti-SRBC titers were not significantly different. When compared to the E+ diet, the AIE+ diet increased (P < 0.01) DFI (24%), DWG (41%) and feed efficiency (13%).

Comparison of two ammoniation procedures to reduce the toxicity of endophyte-infected tall fescue seed fed to rats.

To determine the effect of extending the duration of ammonia (2% dry matter basis) treatment ti'om 1 to 5 wk on the toxicity of endophyte-infected tall fescue seed, 60 male Harlan Sprague-Dawley rats were randomly assigned to the following six treatments during a 28-d trial: endophyte-free (E-), endophyte-infected (E+), 1 wk ammoniated endophyte-fee (1AE-), 1 wk ammoniated endophyte-infected (1AE+), 5 wk ammoniated endophyte-free (5AE-), and 5 wk ammoniated endophyte-infected (5AE+) tall fescue seed. The concentration of total pyrrolizidine alkaloids (N-acetyl and N-formyl loline) or E+ rescue was reduced from 4203 12 g/g to 3009 and 2533 I-tg/g by the 1AE+ and 5AE+ treatments, respectively. Ergovaline was lowered from 3.77 to 1.57 12 g/g by 1AE+ and eliminated by 5AE+. Endophyte-infected treatment groups had depressed (P < 0.0001) dally feed intakes (DFI), daily weight gains (DWG), feed efficiencies (G/F), primary antibody responses, and T cell and B cell mitogenic responses than endophyte-free treatment groups. Ammoniation of endophyte-infected rescue seed improved DFI and DWG (P < 0.0001) and G/F (P < 0.05); however, there was no difference in performance criteria between the 1-wk and 5-wk ammoniation treatments. Endophyte-induced depressions in immune function were not alleviated by ammoniation.

Effects of exogenous somatostatin and cysteamine on net nutrient flux across the portal-drained viscera and liver of sheep during intraduodenal infusion of starch hydrolysate and casein.

We used eight Polypay wethers (36 +/- .6 kg BW) fitted with hepatic portal, hepatic venous, mesenteric arterial and venous, and duodenal catheters in a crossover design experiment to determine the influence of somatostatin (SRIF) on splanchnic metabolism. Each crossover period consisted of 14 d, with net flux of nutrients and hormones (venoarterial differences x blood flow) measured on d 14. Before flux measurements, wethers received an i.v. dose (0 h) of either 0 (vehicle) or 50 mg x kg BW(-1) x 10 min(-1) cysteamine (CSH, SRIF-depleting agent) followed by a continuous duodenal infusion (h 10 to 22) of a starch hydrolysate-casein solution. Six sets of arterial, portal, and hepatic blood samples were obtained (h 12 to 16), after which a primed (10 microg), continuous jugular infusion of SRIF-14 (5.0 microg x kg BW(-1) x h(-1)) was initiated and sampling protocol repeated (h 18 to 22). Cysteamine administration increased (P < .01, vs control) portal and hepatic blood flow in the absence of exogenous SRIF (CSH x SRIF, P < .01). Net portal-drained viscera (PDV) release of glucose, alpha-amino N, ammonia N, beta-hydroxybutyrate, and oxygen consumption were decreased (P < or = .10) and lactate release increased (P = .005) during SRIF infusion. The CSH increased (P < .05) PDV release of beta-hydroxybutyrate and insulin and increased (P = .09, CSH alone vs control) net release of glucose in the absence of exogenous SRIF. Exogenous SRIF increased (P = .10) and CSH decreased (P = .09) net hepatic glucose output, whereas liver oxygen consumption was decreased (P = .04) with exogenous SRIF and increased (P = .01) with CSH. Net total splanchnic alpha-amino N release and oxygen consumption were decreased (P < .10) with exogenous SRIF, but CSH increased (P < .05) insulin release and oxygen consumption. These data provide initial evidence for a regulatory involvement of SRIF in visceral metabolism in ruminants.

Coconut oil as a protective carrier of dietary vitamin A fed to ruminants.

Safflower and coconut oil were compared as protective carriers of dietary vitamin A supplemented to abomasally cannulated sheep. Vitamin A, 240,000 I.U., was predissolved in 11.7 g of safflower or coconut oil and bolused directly into the rumen of mature wethers along with 4 g of chromic oxide. The vitamin A was pre-dissolved in 0, 11.7, 23.4 or 35.0 g of coconut oil in experiment 2. Determination of carrier oil protectiveness of solubilized dietary vitamin A was based on recoveries of vitamin A supplement and chromic oxide in abomasal digesta 24 h post dosage. Vitamin A recoveries were significantly higher (P < 0.05) when dissolved in coconut oil (55.6%) compared to safflower oil (35.5%). Recoveries of vitamin A in abomasal digesta increased linearly (P < 0.01) with the amount of carrier coconut oil in experiment 2. Results of these experiments support the potential use of coconut oil as a protective carrier of ruminal labile vitamin A.

Effects of cysteamine on pulsatile growth hormone release and plasma insulin concentrations in sheep.

The effects of cysteamine (CSH; 0, 50, or 100 mg/kg BW), a somatostatin depleting agent, on growth hormone (GH) and insulin (INS) secretion were studied in sheep (Ovis aries). Cysteamine was administered as a single intragastric bolus on day 0 (0900). Jugular blood samples were collected at 15-min (GH) and 2-hr (INS) intervals over an 8-hr period (1100-1900) on day 0, 3, and 7. Intragastric administration of CSH at 50 mg/kg BW augmented (quadratic, P = .04) mean plasma GH concentration, with the greatest response occurring on day 3. Baseline GH concentrations were elevated in wethers dosed with 50 mg/kg BW CSH on day 3, whereas wethers dosed with 100 mg/kg BW CSH had lower baseline GH concentrations on day 0 (CSH x day interaction, P = .02). Cysteamine administration increased GH pulse amplitude (quadratic, P = .15), with the greatest magnigtude of change occurring with 50 mg/kg BW CSH on day 0 and 3. Frequency of GH pulses was increased (quadratic, P = .10) following CSH treatment. Administration of 100 mg/kg BW CSH augmented plasma INS on day 0 (CSH x day interaction, P = .09). These findings indicate that CSH alters GH and INS secretion in a dose-dependent and temporal manner. The observed changes in mean and baseline plasma GH concentrations associated with 50 mg/kg BW CSH are consistent with somatostatin depletion; however, higher doses of CSH appear to disrupt GH secretion by an alternative mechanism.

Cysteamine-induced depletion of somatostatin in sheep: time course of depletion and changes in plasma metabolites, insulin, and growth hormone.

Eight crossbred wethers (51 +/- 2 kg BW), surgically fitted with abomasal cannulas, were used to determine the extent and time course of cysteamine (CSH)-induced depletion of somatostatin (SRIF) in abomasal tissue and associated changes in plasma metabolites, insulin, and growth hormone (GH). Cysteamine was administered as a single i.v. bolus (50 mg.kg BW-1 x 10 min-1) on d 0. Abomasal biopsies were obtained on d -7, -3, 0, 1, 3, and 10. On d 0, additional biopsies were taken at 2, 4, and 8 h after CSH administration. Jugular blood samples were collected over 8 h at 15-min intervals on d -2, 0, and 1. Cysteamine administration decreased (P < .05) tissue SRIF on d 0 (2, 4, and 8 h), 1, and 3; maximal depletion (42 to 55% of Pre-treatment; Pre-trt) occurred during the initial 24 h, returning to Pre-trt by d 10. Gel chromatography of pooled -7 d abomasal tissue extracts showed five peaks of SRIF immunoreactivity; the predominate peak eluted in the same position as synthetic SRIF-14. Plasma glucose, lactate, and NEFA concentrations increased (P = .001) after CSH administration and reached peak at 2 h after treatment and declined to Pre-trt concentrations by 24 h. Insulin increased (P = .001) to a maximum at h 4 and returned to Pre-trt by 24 h. Mean and baseline GH were higher (P < .07) on day of CSH administration, and pulse amplitude was lower (P < .10) on d 0 and 1. These data show that CSH rapidly reduces SRIF in abomasal tissue in a reversible manner; suggesting that CSH-treated sheep may provide a SRIF-deficient model for studying the physiological role of SRIF in ruminants.

In vitro and in vivo ruminal and physiological responses to endophyte-infected tall fescue.

Relationships between alkaloid compounds in endophyte-infected tall fescue and ruminal metabolism were studied in two experiments. In the first experiment, different combinations of the pyrrolizidine alkaloids, N-formyl and N-acetyl loline, were incubated with ruminal fluid for 0, 24, or 48 h. Rate of disappearance of N-formyl and N-acetyl loline increased over time. After 48 h, disappearance of N-formyl loline and combinations of N-formyl and N-acetyl loline was greater than N-acetyl loline. Significant amounts of N-formyl and N-acetyl loline were metabolized and converted to loline. In the second experiment, abomasally cannulated sheep were fed increasing amounts of endophyte-infected feed to compare diet digestibility, alkaloid metabolism, and physiological responses. Total tract DM digestibility was greatest for the endophyte-free diet, as were ruminal and total tract ADF, ruminal NDF, and total tract CP digestibilities. N-Formyl and N-acetyl loline recoveries averaged 5% from abomasal contents and 0% in feces. Sixty-eight percent of the pyrrolizidine alkaloids recovered in abomasal contents had been metabolizable to loline. Ergot alkaloids administered in the diet were recovered (50 to 60%) in the abomasal contents, but recovery was only 5% in fecal collections. No significant differences occurred in the physiological parameters measured. Results indicate that response to endophyte-infected tall fescue may be influenced by ruminal metabolism.