Ractopamine withdrawal, depletion, and residue testing in beef cattle

2019 Fall.Includes bibliographical references.Studies were conducted to evaluate use of ractopamine hydrochloride (RH) in beef cattle production and the effect of various withdrawal times and depletion periods on residues in tissues and fluids collected from live and harvested animals. Primary objectives of these studies were: i) to develop and validate a LC-MS/MS assay to determine if detectable and quantifiable levels of RH can be detected in digestive tract-derived edible offal items of cattle resulted from tissue residues or residual ingesta contamination; ii) to determine presence of ractopamine in tissues after 12 h, 2, 4, and 7 days of withdrawal (in comparison to negative control cattle which did not receive RH); iii) to develop U.S. beef industry best practices for RH use for export to the Chinese market; and iv) to test the impact of withdrawal from ractopamine hydrochloride in the diets of feedlot cattle for 2, 4, or 7 days on residues for parent and total ractopamine in muscle, fat, rendered tallow, and large intestines in contrast to a true negative control group as well as validate and test feed samples to verify ractopamine presence using LC-MS/MS protocols. In the first study, tissue samples and corresponding rinsates from 10 animals were analyzed for parent and total ractopamine (tissue samples only). The lower limit of quantitation was between 0.03 - 0.66 ppb depending on tissue type, and all tissue and rinsate samples tested had quantifiable concentrations of ractopamine. The greatest concentration of tissue specific ractopamine metabolism (represented by higher total vs. parent ractopamine levels) were observed in liver and small intestine. Contamination from residual ingesta (represented by detectable ractopamine in rinsate samples) only was detected in small intestine, with a measured mean concentration of 19.7 ppb (+/- 12.2 ppb). Taken together, these results underscored the importance of the production process and suggested that improvements may be needed to reduce likelihood of contamination from residual ractopamine in digestive tract-derived edible offal tissues for market. In the second study, liver and muscle samples were collected after 2, 4, and 7 days of withdrawal from RH due to regulatory issues surrounding 12-h samples. Parent and total ractopamine residues in individual liver samples ranged from a minimum of 3.40 and 3.46 ppb, respectively, for the control treatment group, to a maximum of 3.54 and 14.19 ppb, respectively, for the 2-day withdrawal treatment group. For the individual muscle samples, parent and total ractopamine concentrations ranged from below the limit of quantification (0.12 ppb) in the control samples, to 1.13 (parent ractopamine) and 1.72 ppb (total ractopamine) in 2-day withdrawal samples. Therefore, overall, parent and total ractopamine concentrations detected in the liver and muscle samples fell far below the MRL set by Codex and FDA. The greatest parent and total ractopamine levels (282.40 and 289.85 ppb, respectively) were detected after 12 h withdrawal in individual large intestine samples, followed by small intestine (142.26 and 181.91 ppb, respectively) and omasum (109.70 and 116.90 ppb, respectively) samples. Because detectable levels of ractopamine were identified in tissues collected from control animals (i.e., animals not receiving RH in their ration), further research was conducted to determine potential sources of ractopamine contamination, and frequency and accuracy of testing in global markets. For example, eight feed-grade tallow samples were analyzed for parent and total ractopamine presence as a potential source of contamination, especially in cattle not receiving ractopamine in their rations. Ractopamine concentrations of 0.40 to 50.80 ppb were obtained for these tallow samples. While this could potentially explain the detectable levels of ractopamine residues found in control samples and the fact that 7-day withdrawal did not result in non-detectable levels, further research looking at tallow recycling and residual proteins in tallow is necessary to understand the implications of contaminated tallow on residue levels across tissues. Data from the current study may be useful in developing new recommendations for RH use and withdrawal to beef cattle producers in the U.S. who intend to export to global markets. Results from the third study revealed several items of interest, for example; RH declines rapidly in the lower GI of beef cattle, with levels below detection by day four. Additionally, there is a very small likelihood of RH cross-contamination via tallow inclusion in diets. Finally, the fourth study indicated that RH residues can, in fact, be quite low; however, because of limits of detection which are above zero, it is nearly impossible to quantify a level as 0.00 ppb, making zero tolerance requirements insurmountable. Overall, results of these studies were promising in that they showed that RH levels were lower than once thought, but there is a long way to go before zero-tolerance requirements can be met

Evaluation of interleukin-3 in blood-stage immunity against murine malaria Plasmodium yoelii

Malaria is a mosquito-borne infection caused by the parasitic protozoan Plasmodium. This disease infects over 200-300 million people and causes nearly 400,000 deaths every year. Our laboratory previously examined malarial infection caused by Plasmodium berghei NK65, a lethal rodent strain that induces symptoms similar to those observed in humans. The results of this previous study indicated that the hematopoietic growth factor and immunoregulatory cytokine interleukin-3 (IL-3) suppressed protective immunity against infection with P. berghei NK65. However, the extent to which IL-3 contributes to host defense against blood-stage malaria infection caused by other Plasmodium species remains to be determined. In the present study, we have examined the roles of IL-3 in host defense against blood-stage malaria by using IL-3-deficient or “knockout” (KO) mice infected with either nonlethal P. yoelii 17XNL or lethal P. yoelii YM parasites. Survival and parasitemia were measured to monitor the course of infection in wild-type (WT) and IL-3 KO mice. We also characterized parameters indicative of a protective immunity, such as the development of splenomegaly and parasitized red blood cell (pRBC) levels. Surprisingly, we found that IL-3 did not significantly alter the normal clinical course of infection caused by these two Plasmodium strains. These studies indicate that the ability of IL-3 to influence blood-stage malaria infection is dependent on the particular Plasmodium species used to infect animals. These studies also suggest that Plasmodium species may differ in their ability to stimulate IL-3 production and/or differ in their ability to induce a type of host immune response that is IL-3 dependent

The Effect of Disfluency on the Framing Effect

This study investigated the framing effect and examined whether disfluency reduces susceptibility to framing. Prior work has shown that when information is presented in a fluent manner individuals process the content quickly, however when it is presented in a disfluent hard-to-read manner more analytical processing systems are activated. The current study examined the impact of fluency and dual process theory on framing susceptibility. Participants completed three classic decision problems (Asian Disease Problem, School Dropout Prevention Problem, and Fatal Disease Problem) with answers written in a risk seeking or risk averse manner and the font manipulated. The framing effect was again observed for these decision problems, but importantly was reduced in the disfluent conditions, as well as for participants more likely to use System 2 processes. These results suggest that simple font manipulations can have a powerful effect on decision making

The Three-Dimensional Structure of Cassiopeia A

We used the Spitzer Space Telescope's Infrared Spectrograph to map nearly the entire extent of Cassiopeia A between 5-40 micron. Using infrared and Chandra X-ray Doppler velocity measurements, along with the locations of optical ejecta beyond the forward shock, we constructed a 3-D model of the remnant. The structure of Cas A can be characterized into a spherical component, a tilted thick disk, and multiple ejecta jets/pistons and optical fast-moving knots all populating the thick disk plane. The Bright Ring in Cas A identifies the intersection between the thick plane/pistons and a roughly spherical reverse shock. The ejecta pistons indicate a radial velocity gradient in the explosion. Some ejecta pistons are bipolar with oppositely-directed flows about the expansion center while some ejecta pistons show no such symmetry. Some ejecta pistons appear to maintain the integrity of the nuclear burning layers while others appear to have punched through the outer layers. The ejecta pistons indicate a radial velocity gradient in the explosion. In 3-D, the Fe jet in the southeast occupies a "hole" in the Si-group emission and does not represent "overturning", as previously thought. Although interaction with the circumstellar medium affects the detailed appearance of the remnant and may affect the visibility of the southeast Fe jet, the bulk of the symmetries and asymmetries in Cas A are intrinsic to the explosion.Comment: Accepted to ApJ. 54 pages, 21 figures. For high resolution figures and associated mpeg movie and 3D PDF files, see http://homepages.spa.umn.edu/~tdelaney/pape

The medical student

The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine

BioTIME: A database of biodiversity time series for the Anthropocene.

MotivationThe BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene.Main types of variables includedThe database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record.Spatial location and grainBioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2).Time period and grainBioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year.Major taxa and level of measurementBioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates.Software format.csv and .SQL

Recent research on Gulf War illness and other health problems in veterans of the 1991 Gulf War: Effects of toxicant exposures during deployment

Veterans of Operation Desert Storm/Desert Shield - the 1991 Gulf War (GW) - are a unique population who returned from theater with multiple health complaints and disorders. Studies in the U.S. and elsewhere have consistently concluded that approximately 25-32% of this population suffers from a disorder characterized by symptoms that vary somewhat among individuals and include fatigue, headaches, cognitive dysfunction, musculoskeletal pain, and respiratory, gastrointestinal and dermatologic complaints. Gulf War illness (GWI) is the term used to describe this disorder. In addition, brain cancer occurs at increased rates in subgroups of GW veterans, as do neuropsychological and brain imaging abnormalities. Chemical exposures have become the focus of etiologic GWI research because nervous system symptoms are prominent and many neurotoxicants were present in theater, including organophosphates (OPs), carbamates, and other pesticides; sarin/cyclosarin nerve agents, and pyridostigmine bromide (PB) medications used as prophylaxis against chemical warfare attacks. Psychiatric etiologies have been ruled out. This paper reviews the recent literature on the health of 1991 GW veterans, focusing particularly on the central nervous system and on effects of toxicant exposures. In addition, it emphasizes research published since 2008, following on an exhaustive review that was published in that year that summarizes the prior literature (RACGWI, 2008). We conclude that exposure to pesticides and/or to PB are causally associated with GWI and the neurological dysfunction in GW veterans. Exposure to sarin and cyclosarin and to oil well fire emissions are also associated with neurologically based health effects, though their contribution to development of the disorder known as GWI is less clear. Gene-environment interactions are likely to have contributed to development of GWI in deployed veterans. The health consequences of chemical exposures in the GW and other conflicts have been called "toxic wounds" by veterans. This type of injury requires further study and concentrated treatment research efforts that may also benefit other occupational groups with similar exposure-related illnesses

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Search for W' boson production in the W'->tb decay channel

We present a search for the production of a new heavy gauge boson W' that decays to a top quark and a bottom quark. We have analyzed 230 pb^{-1} of data collected with the Dzero detector at the Fermilab Tevatron collider at a center-of-mass energy of 1.96 TeV. No significant excess of events above the standard model expectation is found in any region of the final state invariant mass distribution. We set upper limits on the production cross section of W' bosons times branching ratio to top quarks at the 95% confidence level for several different W' boson masses. We exclude masses between 200 GeV and 610 GeV for a W' boson with standard-model-like couplings, between 200 GeV and 630 GeV for a W' boson with right-handed couplings that is allowed to decay to both leptons and quarks, and between 200 GeV and 670 GeV for a W' boson with right-handed couplings that is only allowed to decay to quarks.Comment: 9 pages, 6 figures, accepted by Phys. Lett.