Incidence of Escherichia coli O157:H7 in frozen beef patties produced over an 8-hour shiftt

A ground beef patty processor detected Escherichia coli O157:H7 in five production lots during routine testing with polymerase chain reaction (PCR) technology. This finding stimulated research to determine the incidence and potential entry points of the pathogen during processing. One of these lots (53,960 kg) was divided into 71 pallets (760 kg each) of food service ground beef patties. Ten cartons (19 kg each) were removed from each pallet, for a total of 710 cartons. Four patties were taken from each carton and subdivided to provide comparable samples for E. coli O157:H7 analyses by three different laboratories. Two laboratories employed different immunoassay tests, and one used PCR to screen samples. One sample set was analyzed for aerobic plate, coliform, and E coli Biotype I counts to determine if any relationship existed between these microbial groups and the incidence of E. coli O157:H7. For 73 samples, presumptive positive results for E. coli O157:H7 were obtained by one or more methods. For 48 of these 73 samples, positive results for the pathogen were culture confirmed. The largest number (29) of culture-confirmed positive E. coli O157:H7 results were detected by PCR. Most positive results were obtained during a short segment of processing. All culture-confirmed E. coli O157:H7 strains were further characterized by two genetic subtyping techniques, resulting in two to four different patterns, depending on the subtyping procedure employed. For any sample tested, the aerobic plate count was < 3.0 log CFU/g, and coliform and E. coli Biotype I counts were < or = 1.00 log CFU/g. The results of this study suggest that most positive samples were associated with a contaminated batch of raw material introduced just before the 1725- to 1844-h processing segment. These results also indicate that more aggressive sampling plans and genetic screening technologies such as PCR may be used to better detect low levels of E. coli O157:H7 in ground beef products.     

Switchgrass extractives to mitigate Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium contamination of romaine lettuce at pre- and postharvest

The antimicrobial potential of switchgrass extractives (SE) was evaluated on cut lettuce leaves and romaine lettuce in planta, using rifampicin-resistant Escherichia coli O157:H7 and Salmonella Typhimurium strain LT2 as model pathogens. Cut lettuce leaves were swabbed with E. coli O157:H7 or S. Typhimurium followed by surface treatment with 0.8% SE, 0.6% sodium hypochlorite, or water for 1 to 45 min. For in planta studies, SE was swabbed on demarcated leaf surfaces either prior to or after inoculation of greenhouse-grown lettuce with E. coli O157:H7 or S. Typhimurium; the leaf samples were collected after 0, 24, and 48 h of treatment. Bacteria from inoculated leaves were enumerated on tryptic soy agar plates (and also on MacConkey's and XLT4 agar plates), and the recovered counts were statistically analyzed. Cut lettuce leaves showed E. coli O157:H7 reduction between 3.25 and 6.17 log CFU/leaf, whereas S. Typhimurium reductions were between 2.94 log CFU/leaf and 5.47 log CFU/leaf depending on the SE treatment durations, from initial levels of ∼7 log CFU/leaf. SE treatment of lettuce in planta, before bacterial inoculation, reduced E. coli O157:H7 and S. Typhimurium populations by 1.88 and 2.49 log CFU after 24 h and 3 h, respectively. However, SE treatment after bacterial inoculation of lettuce plants decreased E. coli O157:H7 populations by 3.04 log CFU (after 0 h) with negligible reduction of S. Typhimurium populations. Our findings demonstrate the potential of SE as a plant-based method for decontaminating E. coli O157:H7 on lettuce during pre- and postharvest stages in hurdle approaches.     

Weight suppression and weight rebound in ex-smokers treated with fluoxetine.

Fluoxetine's effect (30 mg, 60 mg, and placebo) on postcessation weight gain was studied among participants from a randomized, double-blind 10-week smoking cessation trial who met strict criteria for abstinence and drug levels. It was hypothesized that (a) fluoxetine would dose-dependently suppress postcessation weight gain and (b) drug discontinuation would produce dose-dependent weight rebound. During the on-drug phase, placebo participants gained weight linearly (M?=?2.61 kg), exceeding both fluoxetine groups (30-mg M?=?1.33 kg, 60-mg M?=?1.25 kg). Weight suppression was initially greater for 60 mg than 30 mg, but both were followed by weight gain. Six months off-drug produced greater dose-dependent weight rebound for 60 mg than 30 mg or placebo. Considering both on- and off-drug phases, weight gain for 60 mg of fluoxetine (M?=?6.5 kg) was comparable with that for placebo (M?=?4.7 kg) but greater than that for 30 mg (M?=?3.6 kg). Fluoxetine appears to forestall postcessation weight gain, allowing time for the weight-conscious smoker to focus on quitting smoking rather than on preventing weight gain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

BeamDyn: a high‐fidelity wind turbine blade solver in the FAST modular framework

This paper presents a numerical implementation of the geometrically exact beam theory based on the Legendre‐spectral‐finite‐element (LSFE) method. The displacement‐based geometrically exact beam theory is presented, and the special treatment of three‐dimensional rotation parameters is reviewed. An LSFE is a high‐order finite element with nodes located at the Gauss–Legendre–Lobatto points. These elements can be an order of magnitude more computationally efficient than low‐order finite elements for a given accuracy level. The new module, BeamDyn, is implemented in the FAST modularization framework for dynamic simulation of highly flexible composite‐material wind turbine blades within the FAST aeroelastic engineering model. The framework allows for fully interactive simulations of turbine blades in operating conditions. Numerical examples are provided to validate BeamDyn and examine the LSFE performance as well as the coupling algorithm in the FAST modularization framework. BeamDyn can also be used as a stand‐alone high‐fidelity beam tool. Copyright © 2017 John Wiley & Sons, Ltd.     

Embracing brain and behaviour: Designing programs of complementary neurophysiological and behavioural studies

NeuroIS—the methods and knowledge of neuroscience applied to the information systems (IS) domain—has become an established research field within the IS discipline. A key advantage of NeuroIS is its ability to provide insights into human cognition beyond those obtained using behavioural techniques alone. Nevertheless, in neuroscience, there is renewed interest in examining behaviour together with neurophysiological methods to better inform our understanding of neural processes. In this research opinion article, we argue that in the field of NeuroIS, there is an opportunity for hybrid programs of study that combine neurophysiological and behavioural methods in a complementary manner. We outline four strategies for designing complementary neurophysiological and behavioural experiments in a research program: (1) observe the relationship between neural processes and behavioural change; (2) combine neurophysiological and behavioural methods to enhance internal, external, and ecological validity; (3) extend, rather than replicate, experiments based on theory; and (4) use neurophysiological and behavioural experiments together to evaluate IT artefact design. By applying these strategies, researchers can more effectively design programs using complementary neurophysiological and behavioural methods, which, in turn, can help to provide richer insights into the phenomena under study as well as accelerate the advancement of IS knowledge.     

A GC–MSD method for analysis of dimethyl sulfate in palm oil-based esterquat

Dimethyl sulfate (DMS) is a quarternizing agent for esteramine used for the synthesis of esterquat. To date there is no reliable published method for quantification of DMS in palm-based esterquat. Esterquat is used in the formulation of personal care and textile cleaning. The process of quaternization is usually incomplete and there will be unreacted DMS. This work presents a new simple method involving solvent extraction of DMS followed by analysis with gas chromatography–mass spectrometry detector to quantify the unreacted DMS. This method was validated as per International Council for Harmonization requirements. This novel method showed good repeatability (relative standard deviation [RSD] < 5%) and inter-day with different analyst reproducibility (RSD < 5%). The limits of detection and quantification were 5 and 10 μg mL⁻¹, respectively. The accuracy of the method was evaluated by the analysis of spiked samples and it was found that good recovery was found at spiking levels of 20, 30, and 50 μg mL⁻¹ with % recovery falling within the 80%–120% acceptable limit. However, at 10 μg mL⁻¹, the percentage recovery was slightly below the recommended limit.     

A compendium of processor allocation strategies for two-dimensional mesh connected systems

Multiple processor systems are an integral part of today's high-performance computing environment. Such systems are often configured as a two-dimensional grid of processors called a mesh. Tasks compete for rectangular submeshes of this mesh. The choice of submesh allocation strategy can significantly affect the level of processor utilization and a task's waiting time. In addition, the execution speed of various allocation algorithms varies widely, which can further affect system performance. This paper describes and categorizes several submesh allocation strategies, including a previously unreported method that is superior to other methods in terms of execution speed. The paper includes results of simulation studies used to compare the performance characteristics of the most efficient allocation strategies in each category.