Laboratory evaluation of 3M Petrifilms and University of Minnesota Bi-plates as potential on-farm tests for clinical mastitis

The objective was to determine test characteristics and compare 2 potential on-farm culture systems for clinical mastitis, the Minnesota Easy Culture System II Bi-plate and Petrifilm. The tests were evaluated using clinically positive mastitic milk samples (n = 282) to determine their ability to differentiate appropriate treatment groups; all cases that had gram-positive growth were considered treatment candidates (n = 161), whereas cases that grew gram-negative organisms only or yielded no bacterial growth were classified as no treatment (n = 121). For Petrifilm, both undiluted and 1:10 diluted milk samples were used. To create treatment categories, 2 types of Petrifilms were used, Aerobic Count (AC) and Coliform Count (CC). Both Bi-plates and Petrifilms were read after 24 h of incubation. Analysis was conducted at various colony count thresholds for the Petrifilm test system. The combination of Petrifilms that had the highest sensitivity classified a case as gram-negative if there were ≥20 colonies present on the CC. If there were <20 colonies present on the CC and >5 colonies present on the AC, a case would be classified as gram-positive. The Bi-plate had a sensitivity of 97.9% and a specificity of 68.6%. The Petrifilm test system had a sensitivity of 93.8% and a specificity of 70.1%. There was no significant difference in the sensitivities between the tests. All Bi-plates and Petrifilms were read by a laboratory technician and a group of masked readers with limited microbiology training. Kappa values for the masked readers were 0.75 for Bi-plates and 0.84 and 0.86 for AC and CC Petrifilms, respectively. The Bi-plate and Petrifilm were able to successfully categorize clinical cases of mastitis into 2 treatments based on their ability to detect the presence of a gram-positive organism. Neither method had the ability to determine if a sample was contaminated. The results of this study indicate that both tests were able to appropriately categorize cases, which could potentially result in a reduction in the quantity of antibiotics used to treat clinical cases of mastitis.     

Antecedents of flow in online shopping: a test of alternative models

Flow is an optimal state of experience that has been studied in various situations, including online environments. In such environments, it has been found to be positively related to exploratory behaviour, revisit and purchase intention, and positive attitude towards web sites. Based on flow theory, this study tests the complete structure of the flow model as it was originally formulated in an online shopping context. The role of the preconditions of flow is elaborated and the effect of web site complexity, an important interface design variable, on flow is examined. Results show that web site complexity affects flow through the mediating effects of the three preconditions of flow. Theoretical and practical implications of this finding are discussed.     

The effects of topical treatments with 6-pentyl-2-pyrone and structural analogues on stem end postharvest rots in kiwifruit due to Botrytis cinerea

The picking wounds in kiwifruit formed by breaking off the pedicels at harvest were treated topically with the naturally occurring lactones 6-pentyl-2-pyrone (6PP), decano-δ-lactone (DL) and 2-deceno-δ-lactone (massoialacetone: ML), and with the synthetic fungicide vinclozolin. 6PP was applied at rates from 0·4 to 4 mg, neat or diluted in oil, water or acetone. 6PP treatments consistently reduced the incidence of Botrytis cinerea storage rots to low levels in both inoculated and naturally infected fruit. For inoculated fruit, control was achieved even when treatment was delayed up to 2 days from inoculation. ML gave significant but lesser control than 6PP, while DL was not generally effective. DL was also less effective than ML or 6PP at suppressing B cinerea inoculum germination in vitro. Much lower rates of vinclozolin (8 or 70 μg) also gave significant control of storage rots. Such topical treatment methods permit control of storage diseases with similar application quantities to currently accepted preharvest fungicide treatments. © 1998 SCI.     

Thermal modelling using ASTEC3 software

This paper describes the application of ASTEC3, a general purpose analogue electronic circuit simulation package, to the analysis of thermal properties of given structures. The modelling of each system is considered for both conduction and convection mechanisms, radiation being assumed to play a very minor role in heat dissipation from most electrical circuits. A procedure is given for the modelling of one-, two- and three-dimensional thermal problems which is then used for the simulation of relatively simple examples. The results obtained with ASTEC3 are compared with results determined by using more traditional and independent techniques.     

Opposing Roles of GSK3α and GSK3β Phosphorylation in Platelet Function and Thrombosis

One of the mechanisms by which PI3 kinase can regulate platelet function is through phosphorylation of downstream substrates, including glycogen synthase kinase-3 (GSK3)α and GSK3β. Platelet activation results in the phosphorylation of an N-terminal serine residue in GSK3α (Ser21) and GSK3β (Ser9), which competitively inhibits substrate phosphorylation. However, the role of phosphorylation of these paralogs is still largely unknown. Here, we employed GSK3α/β phosphorylation-resistant mouse models to explore the role of this inhibitory phosphorylation in regulating platelet activation. Expression of phosphorylation-resistant GSK3α/β reduced thrombin-mediated platelet aggregation, integrin α_IIbβ₃ activation, and α-granule secretion, whereas platelet responses to the GPVI agonist collagen-related peptide (CRP-XL) were significantly enhanced. GSK3 single knock-in lines revealed that this divergence is due to differential roles of GSK3α and GSK3β phosphorylation in regulating platelet function. Expression of phosphorylation-resistant GSK3α resulted in enhanced GPVI-mediated platelet activation, whereas expression of phosphorylation-resistant GSK3β resulted in a reduction in PAR-mediated platelet activation and impaired in vitro thrombus formation under flow. Interestingly, the latter was normalised in double GSK3α/β KI mice, indicating that GSK3α KI can compensate for the impairment in thrombosis caused by GSK3β KI. In conclusion, our data indicate that GSK3α and GSK3β have differential roles in regulating platelet function.     

Liverpool Visual Assessment Team 1985-1989: 5 years on

An update of the work of the Liverpool Visual Assessment Team. This is a multi-disciplinary team for the assessment, remediation and management of severely visually impaired children in Liverpool and the surrounding region.