71 research outputs found

    Using in situ technique to estimate nutrient availability of six barley varieties for ruminants

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    Non-Peer ReviewedBarley grains are as a main source of feed for ruminants in Canada. Although barley varieties have similar chemical composition, they exhibit different rumen degradation characteristics and nutrient availability. The objective of this study was to estimate nutrient availability of the six barley varieties using nylon bags incubated for 0, 2, 4, 8, 12, 24 and 48 h in the rumen of dairy cow and determine the rumen degradation parameters of DM, CP and starch according to the first order degradation kinetics equation. The results indicated that the barley varieties showed different degradation rate (Kd) of DM, CP and starch during incubation period. CDC Trey was the highest (P<0.05) in effective degradability of DM (498.04g/kg) while AC Metcalfe showed the highest (P<0.05) effective degradability of CP (63.06g/kg) and starch (344.82g/kg) compared with other barley varieties. CDC Helgason had the largest size of rumen undegradable fraction of DM (640.21g/kg), CP (83.85g/kg, NRC 2001 model) and starch (321.85g/kg). Feeds degradation features from this study involved nutrients utilization in ruminant digestive systems. Further study to investigate and compare the structural/chemical make-up characteristics between barley varieties may provide more information as to why barley varieties exhibit different biodegradation behaviors

    Using synchrotron-based FTIR microspectroscopy (SFTIRM) to reveal the differences of endosperm structural and chemical make-up among six barley varieties

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    Non-Peer ReviewedBarley grains are widely used for malting and feeding purposes in Canada. Although barley varieties have similar chemical composition, they exhibit different rumen degradation characteristics and nutrient availability. The objectives of this study was to determine structural make-up features and identify the structural differences in chemical functional groups in endosperm tissue among the six barley varieties using ultra-spatially resolved synchrotron-based FTIR microspectroscopy (SFTIRM). The results indicated that the barley varieties showed significant differences in terms of peak area intensities and the peak ratios of the amide I (1650 cm-1) and amide II (1550 cm-1), cellulosic compounds (ca. 1240 cm-1), and non-structural carbohydrates (NSC, starch) peak (1025 cm-1). The synchrotron-based FTIR spectroscopic information associated with structural and chemical make-up characteristics of barley grains may provide more information as to why barley varieties exhibit different biodegradation behaviors

    Effects of barley based diets with three different rumen degradable protein balances on performance and carcass characteristics of feedlot steers

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    Non-Peer ReviewedThe objective of this study was to determine the effect of dietary optimal or suboptimal rumen available protein to energy ratios generated by substituting barley grain by wheat –based dried distillers’ grains with soluble (wDDGS) on finishing feedlot cattle performance. Three hundred crossbred steers were randomly assigned to twelve pens (25 heads in each pen) and fed one of three grain based finishing diets with: (i) negative rumen degradable protein balance (DPB; -12 g/kg DM); (ii) neutral DPB (0 g/kg DM); and (iii) positive DPB (14 g/kg DM). Ration with negative DPB (conventional feed) contained 88.3% rolled barley grain, 7.0% supplement and 4.7% barley silage. For the rations with neutral - and positive DPB, the barley grain was replaced by wDDGS at 11 or 22% of the diet, respectively. Over the 131-d finishing period, animal performance and carcass traits were similar among steers fed either of 3 finishing diets. In conclusion, barley grain in common feedlot diets can be substituted by wDDGS up to 22%, without altering steer performance and carcass characteristics

    Abacavir-Reactive memory T Cells are present in drug naïve individuals

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    Background Fifty-five percent of individuals with HLA-B*57:01 exposed to the antiretroviral drug abacavir develop a hypersensitivity reaction (HSR) that has been attributed to naïve T-cell responses to neo-antigen generated by the drug. Immunologically confirmed abacavir HSR can manifest clinically in less than 48 hours following first exposure suggesting that, at least in some cases, abacavir HSR is due to re-stimulation of a pre-existing memory T-cell population rather than priming of a high frequency naïve T-cell population. Methods To determine whether a pre-existing abacavir reactive memory T-cell population contributes to early abacavir HSR symptoms, we studied the abacavir specific naïve or memory T-cell response using HLA-B*57:01 positive HSR patients or healthy controls using ELISpot assay, intra-cellular cytokine staining and tetramer labelling. Results Abacavir reactive CD8+ T-cell responses were detected in vitro in one hundred percent of abacavir unexposed HLA-B*57:01 positive healthy donors. Abacavir-specific CD8+ T cells from such donors can be expanded from sorted memory, and sorted naïve, CD8+ T cells without need for autologous CD4+ T cells. Conclusions We propose that these pre-existing abacavir-reactive memory CD8+ T-cell responses must have been primed by earlier exposure to another foreign antigen and that these T cells cross-react with an abacavir-HLA-B*57:01-endogenous peptide ligand complex, in keeping with the model of heterologous immunity proposed in transplant rejection

    Completion Dissection or Observation for Sentinel-Node Metastasis in Melanoma.

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    Sentinel-lymph-node biopsy is associated with increased melanoma-specific survival (i.e., survival until death from melanoma) among patients with node-positive intermediate-thickness melanomas (1.2 to 3.5 mm). The value of completion lymph-node dissection for patients with sentinel-node metastases is not clear. In an international trial, we randomly assigned patients with sentinel-node metastases detected by means of standard pathological assessment or a multimarker molecular assay to immediate completion lymph-node dissection (dissection group) or nodal observation with ultrasonography (observation group). The primary end point was melanoma-specific survival. Secondary end points included disease-free survival and the cumulative rate of nonsentinel-node metastasis. Immediate completion lymph-node dissection was not associated with increased melanoma-specific survival among 1934 patients with data that could be evaluated in an intention-to-treat analysis or among 1755 patients in the per-protocol analysis. In the per-protocol analysis, the mean (±SE) 3-year rate of melanoma-specific survival was similar in the dissection group and the observation group (86±1.3% and 86±1.2%, respectively; P=0.42 by the log-rank test) at a median follow-up of 43 months. The rate of disease-free survival was slightly higher in the dissection group than in the observation group (68±1.7% and 63±1.7%, respectively; P=0.05 by the log-rank test) at 3 years, based on an increased rate of disease control in the regional nodes at 3 years (92±1.0% vs. 77±1.5%; P&lt;0.001 by the log-rank test); these results must be interpreted with caution. Nonsentinel-node metastases, identified in 11.5% of the patients in the dissection group, were a strong, independent prognostic factor for recurrence (hazard ratio, 1.78; P=0.005). Lymphedema was observed in 24.1% of the patients in the dissection group and in 6.3% of those in the observation group. Immediate completion lymph-node dissection increased the rate of regional disease control and provided prognostic information but did not increase melanoma-specific survival among patients with melanoma and sentinel-node metastases. (Funded by the National Cancer Institute and others; MSLT-II ClinicalTrials.gov number, NCT00297895 .)

    US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report

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    This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in Dark Matter" held at University of Maryland on March 23-25, 2017
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