Preventive medicine and management in beef feedlots

The objectives of beef feedlot preventive medicine are to reduce morbidity, mortality and culling rates, maximize feed efficiency and optimize expenditures for biologicals and pharmaceuticals. The veterinarian must provide regular inspection of all areas of the feedlot and constantly monitor disease incidence. The provision of advice on vaccination, treatment schedules, necropsies on all dead cattle and the regular analysis of disease and production records are all part of feedlot preventive medicine. All of this is aimed at improving net economical gain for the producer.     

Reduction of poliovirus 1, bacteriophages,Salmonella montevideo,and Escherichia coli O157:H7 on strawberries by physical and disinfectant washes

The efficacy levels of different physical and chemical washing treatments in the reduction of viral and bacterial pathogens from inoculated strawberries were evaluated. Escherichia coli O157:H7, Salmonella Montevideo, poliovirus 1, and the bacteriophages PRD1, phiX174, and MS2 were used as model and surrogate organisms. Chemicals readily available to producers and/or consumers were evaluated as antimicrobial additives for the production of washes. The gentle agitation of contaminated strawberries in water for 2 min led to reductions in microbial populations ranging from 41 to 79% and from 62 to 90% at water temperatures of 22 and 43 degrees C, respectively. Significant reductions (> 98%) in numbers of bacteria and viruses were obtained with sodium hypochlorite (50 to 300 ppm of free chlorine), Oxine or Carnebon (200 ppm of product generating "stabilized chlorine dioxide"), Tsunami (100 ppm of peroxyacetic acid), and Alcide (100 or 200 ppm of acidified sodium chlorite) washes. Overall, 200 ppm of acidified sodium chlorite produced the greatest reductions of microorganisms. Hydrogen peroxide (0.5%) was slightly less effective than free chlorine in a strawberry wash and caused slight fruit discoloration. Cetylpyridinium chloride (0.1%) was effective in the reduction of bacterial species, while trisodium phosphate (1%) was effective against viruses. The consumer-oriented produce wash Fit was very effective (> 99%) in reducing the numbers of bacteria but not in reducing the numbers of viruses. Another wash, Healthy Harvest, was significantly less effective than Fit in reducing bacterial pathogens but more effective for viruses. The performance of automatic dishwashing detergent was similar to that of Healthy Harvest and significantly better than that of liquid dishwashing detergent. Solutions containing table salt (2% NaCl) or vinegar (10%) reduced the numbers of bacteria by about 90%, whereas only the vinegar wash reduced the numbers of viruses significantly (ca. 95%).     

NMR of 89Y in the Copper-Oxide Spin-Chain Compound Ca2+x Y2−x Cu5O10

We report NMR lineshape, spin-lattice relaxation time T ₁, and spin-spin relaxation time T ₂ data at 17 MHz (8.07 T) for ⁸⁹Y in the copper-oxide spin-chain compound Ca_2+x Y_2–x Cu₅O₁₀. For x=0, a broad, asymmetric line with width 90 kHz is observed for T=250–300 K. The spectra exhibit an appreciable average shift (H/H+0.7%) and sharpen at lower temperature, possibly due to increasing intrachain ferromagnetic correlations. T ₁ and T ₂ decrease with decreasing temperature. The Tl data imply a short correlation-time limit, with _e=3–5×10^–11 s. The T ₂ data apparently include a contribution from dipolar interactions with copper nuclei. Relaxation time data for a doped (x=0.5) compound surprisingly show more rapid relaxation.     

Reproducibility in fabrication and analytical performance of polyaniline-coated nanoelectrospray emitters

Nanoelectrospray ionization mass spectrometry is an ideal technique for analysis of biomolecules when sample quantities are limited. With the use of this technique, 1-2 microL of sample can be electrosprayed for long time periods (hours) because of the low flow rate (nanoliters per minute) attainable. However, the long-term durability of such emitters has been an impediment to the routine use of nanoelectrospray. The development of longer-lasting nanoelectrospray emitters has often resulted in increasingly complex and tedious fabrication processes. Furthermore, an easily produced, reproducible, and durable nanoelectrospray emitter is the ultimately desired goal. Here, the reproducibility of the inner diameters and geometry for nanoelectrospray emitter glass substrates is assessed using scanning electron microscopy (SEM). The results indicate that provided that glass pulling parameters remain constant, reproducible inner diameters can be produced from glass capillary tubing within the same batch; however, there are interbatch differences. In addition, SEM revealed reproducible taper geometry could also be obtained. Borosilicate and fused-silica nanoelectrospray emitters produced by these protocols were then coated with polyaniline, and their analytical figures of merit were determined using a triple quadrupole mass analyzer. Over a 1-h run, polyaniline-coated emitters showed fairly stable signal with coefficients of variation ranging from 8.92 to 27.6%. Single-scan detection limits below 1 amol were achieved for polyaniline-coated fused-silica emitters for flow rates averaging <10 nL/min. Linear mass spectrometric response with solution concentration was observed for the polyaniline-coated emitters over the range 10 nM-10 microM, with coefficients of variation ranging from 1.44 to 7.26%. This indicates that when nanelectrospray emitter inner diameters are made reproducibly, it is possible to achieve linear quantitative response for nanoelectrospray.     

Quantification of Protein‐Induced Membrane Remodeling Kinetics In Vitro with Lipid Multilayer Gratings

The dynamic self‐organization of lipids in biological systems is a highly regulated process that enables the compartmentalization of living systems at micro‐ and nanoscopic scales. Consequently, quantitative methods for assaying the kinetics of supramolecular remodeling such as vesicle formation from planar lipid bilayers or multilayers are needed to understand cellular self‐organization. Here, a new nanotechnology‐based method for quantitative measurements of lipid–protein interactions is presented and its suitability for quantifying the membrane binding, inflation, and budding activity of the membrane‐remodeling protein Sar1 is demonstrated. Lipid multilayer gratings are printed onto surfaces using nanointaglio and exposed to Sar1, resulting in the inflation of lipid multilayers into unilamellar structures, which can be observed in a label‐free manner by monitoring the diffracted light. Local variations in lipid multilayer volume on the surface is used to vary substrate availability in a microarray format. A quantitative model is developed that allows quantification of binding affinity (K _D) and kinetics (k_on and k_off). Importantly, this assay is uniquely capable of quantifying membrane remodeling. Upon Sar1‐induced inflation of single bilayers from surface supported multilayers, the semicylindrical grating lines are observed to remodel into semispherical buds when a critical radius of curvature is reached.     

Design of Managed Aquifer Recharge for Agricultural and Ecological Water Supply Assessed Through Numerical Modeling

The Walla Walla Basin, in Eastern Oregon and Washington, USA, faces challenges in sustaining an agricultural water supply while maintaining sufficient flow in the Walla Walla River for endangered fish populations. Minimum summer river flow of 0.71 m³/s is required, forcing irrigators to substitute groundwater from a declining aquifer for lost surface water diversion. Managed Aquifer Recharge (MAR) was initiated in 2004 attempting to restore groundwater levels and improve agricultural viability. The Integrated Water Flow Model (IWFM) was used to compute surface and shallow groundwater conditions in the basin under water management scenarios with varying water use, MAR, and allowable minimum river flow. A mean increase of 1.5 m of groundwater elevation, or 1.5 % of total aquifer storage, was predicted over the model area when comparing maximum MAR and no MAR scenarios where minimum river flow was increased from current level. When comparing these scenarios a 53 % greater summer flow in springs was predicted with the use of MAR. Results indicate MAR can supplement irrigation supply while stabilizing groundwater levels and increasing summer streamflow. Potential increase in long-term groundwater storage is limited by the high transmissivity of the aquifer material. Increased MAR caused increased groundwater discharge through springs and stream beds, benefiting aquatic habitat rather than building long-term aquifer storage. Judicious siting of recharge basins may be a means of increasing the effectiveness of MAR in the basin.     

The preattentive emperor has no clothes: A dynamic redressing.

Preattentive models of early vision have not been supported by the evidence. Instead, an input filtering system, which is dynamically reconfigured so as to optimize performance on the task at hand, is proposed. As a case in point, the authors examined Sagi and Julesz's (1985a) claim that detection tasks are processed preattentively and efficiently (shallow search slopes), whereas discrimination tasks require focal attention and yield inefficient steep slopes. In 5 visual search experiments, efficiency was found to depend not on the nature of the task but on whether the task is single or dual. The second component of a dual task, whether detection or discrimination, is performed inefficiently if it does not fit the configuration of the input system, which had been set optimally for the first component. But, even the second component is processed efficiently if there is enough time to reconfigure the system after processing the first component. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Primary aortic mural thrombus: presentation and treatment

Schizophrenic patients are extremely heavy tobacco smokers. However, a lower incidence of lung cancer in schizophrenic patients has been observed in comparison to other heavy smokers. Nicotine increases the proliferation of pulmonary neuroendocrine tissue, causing the release of a bombesin-like peptide. Thus, bombesin-like peptide levels in urine may be an indicator of precancerous, cigarette-induced lung damage. Bombesin-like peptide levels of 10 schizophrenic smokers and 11 schizophrenic nonsmokers were compared to those of nonschizophrenic subjects matched for age and pack-years of smoking. The nonschizophrenic smokers showed the expected increase in urinary bombesin-like peptide levels, as compared to nonschizophrenic nonsmokers. Schizophrenic patients had lower bombesin-like peptide levels independent of smoking effects. The mechanism of the difference in bombesin-like peptide levels between schizophrenic patients and nonschizophrenic subjects is unknown, but one possibility involves alteration in the alpha 7-nicotinic acetylcholine receptor, which mediates the growth of some neuroendocrine cell lines in vitro.     

Human brain metabolic response to caffeine and the effects of tolerance

OBJECTIVE: Since there is limited information concerning caffeine's metabolic effects on the human brain, the authors applied a rapid proton echo-planar spectroscopic imaging technique to dynamically measure regional brain metabolic responses to caffeine ingestion. They specifically measured changes in brain lactate due to the combined effects of caffeine's stimulation of glycolysis and reduction of cerebral blood flow. METHOD: Nine heavy caffeine users and nine caffeine-intolerant individuals, who had previously discontinued or substantially curtailed use of caffeinated products because of associated anxiety and discomforting physiological arousal, were studied at baseline and then during 1 hour following ingestion of caffeine citrate (10 mg/kg). To assess state-trait contributions and the effects of caffeine tolerance, five of the caffeine users were restudied after a 1- to 2-month caffeine holiday. RESULTS: The caffeine-intolerant individuals, but not the regular caffeine users, experienced substantial psychological and physiological distress in response to caffeine ingestion. Significant increases in global and regionally specific brain lactate were observed only among the caffeine-intolerant subjects. Reexposure of the regular caffeine users to caffeine after a caffeine holiday resulted in little or no adverse clinical reaction but significant rises in brain lactate which were of a magnitude similar to that observed for the caffeine-intolerant group. CONCLUSIONS: These results provide direct evidence for the loss of caffeine tolerance in the human brain subsequent to caffeine discontinuation and suggest mechanisms for the phenomenon of caffeine intolerance other than its metabolic effects on elevating brain lactate.