Development and validation of an ultrasensitive fluorescence planar waveguide biosensor for the detection of paralytic shellfish toxins in marine algae

Marine dinoflagellates of the genera Alexandrium are well known producers of the potent neurotoxic paralytic shellfish toxins that can enter the food web and ultimately present a serious risk to public health in addition to causing huge economic losses. Direct coastal monitoring of Alexandrium spp. can provide early warning of potential shellfish contamination and risks to consumers and so a rapid, sensitive, portable and easy-to-use assay has been developed for this purpose using an innovative planar waveguide device. The disposable planar waveguide is comprised of a transparent substrate onto which an array of toxin-protein conjugates is deposited, assembled in a cartridge allowing the introduction of sample, and detection reagents. The competitive assay format uses a high affinity antibody to paralytic shellfish toxins with a detection signal generated via a fluorescently labelled secondary antibody. The waveguide cartridge is analysed by a simple reader device and results are displayed on a laptop computer. Assay speed has been optimised to enable measurement within 15 min. A rapid, portable sample preparation technique was developed for Alexandrium spp. in seawater to ensure analysis was completed within a short period of time. The assay was validated and the LOD and CCß were determined as 12 pg/mL and 20 pg/mL respectively with an intra-assay CV of 11.3% at the CCß and an average recovery of 106%. The highly innovative assay was proven to accurately detect toxin presence in algae sampled from the US and European waters at an unprecedented cell density of 10 cells/L. © 2012 Elsevier B.V. All rights reserved.

Development and application of a multiple linear regression model to consider the impact of weekly waste container capacity on the yield from kerbside recycling programmes

The paper describes the development and application of a multiple linear regression model to identify how the key elements of waste and recycling infrastructure, namely container capacity and frequency of collection affect the yield from municipal kerbside recycling programmes. The overall aim of the research was to gain an understanding of the factors affecting the yield from municipal kerbside recycling programmes in Scotland. The study isolates the principal kerbside collection service offered by 32 councils across Scotland, eliminating those recycling programmes associated with flatted properties or multi occupancies. The results of a regression analysis model has identified three principal factors which explain 80% of the variability in the average yield of the principal dry recyclate services: weekly residual waste capacity, number of materials collected and the weekly recycling capacity. The use of the model has been evaluated and recommendations made on ongoing methodological development and the use of the results in informing the design of kerbside recycling programmes. The authors hope that the research can provide insights for the ongoing development of methods to optimise the design and operation of kerbside recycling programmes.

Development and characterization of a lux-modified 2,4-dichlorophenol-degrading Burkholderia sp. RASC

lux-marked biosensors for assessing the toxicity and bioremediation potential of polluted environments may complement traditional chemical techniques. luxCDABE genes were introduced into the chromosome of the 2,4-dichlorophenol (2,4-DCP)-mineralizing bacterium, Burkholderia sp. RASC c2, by biparental mating using the Tn4431 system. Experiments revealed that light output was constitutive and related to cell biomass concentration during exponential growth. The transposon insertion was stable and did not interrupt 2,4-DCP-degradative genes, and expression of luxCDABE did not constitute a metabolic burden to the cell. A bioluminescence response was detectable at sublethal 2,4-DCP concentrations: at <10.26 microg ml(-1), bioluminescence was stimulated (e.g. 218% of control), but at concentrations >60 microg ml(-1) it declined to <1%. Investigating the effect of [14C]-2,4-DCP concentration on the evolution of 14CO2 revealed that, for initial concentrations of 2.5-25 microg ml(-1), approximately equals 55% of the added 14C was mineralized after 24 h compared with

The physical activity loyalty card scheme:Development and application of a novel system for incentivizing behaviour change

In the Public Health White Paper "Healthy Lives, Healthy People" (2010), the UK Government emphasised using incentives and "nudging" to encourage positive, healthy behaviour changes. However, there is little evidence that nudging is effective, in particular for increasing physical activity. We have created a platform to research the effectiveness of health-related behaviour change interventions and incentive schemes. The system consists of an outward-facing website, incorporating tools for incentivizing behaviour change, and a novel physical activity monitoring system. The monitoring system consists of the "Physical Activity Loyalty Card", which contains a passive RFID tag, and a contactless sensor network to detect the cards. This paper describes the application of this novel web-based system to investigate the effectiveness of non-cash incentives to "nudge" adults to undertake more physical activity. © 2012 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering.

Development and Validation of a Forklift Truck Powertrain Simulation

Fuel economy has become an important consideration in forklift truck design, particularly in Europe. A simulation of the fuel consumption and performance of a forklift truck has been developed, validated and subsequently used to determine the energy consumed by individual powertrain components during drive cycles.
The truck used in this study has a rated lifting capacity of 2500kg, and is powered by a 2.6 litre naturally aspirated diesel engine with a fuel pump containing a mechanical variable-speed governor. The drivetrain consisted of a torque convertor, hydraulic clutch and single speed transmission.
AVL Cruise was used to simulate the vehicle powertrain, with coupled Mathworks Simulink models used to simulate the hydraulic and control systems and governor. The vehicle has been simulated on several performance and fuel consumption drive cycles with the main focus being the VDI 2198 fuel consumption drive cycle.
To validate the model, a truck was instrumented and measurements taken to compare the performance and instantaneous fuel consumption to simulated values. The fuel injector pump was modified and calibrated to enable instantaneous fuel flow to be measured.
The model has been validated to within acceptable limits and has been used to investigate the effect four different torque converters have on the fuel consumption and performance of the forklift truck. The study demonstrates how the model can be used to compare the fuel consumption and performance trade-offs when selecting drivetrain components.

The canadian longitudinal study on aging (CLSA)

Canadians are living longer, and older persons are making up a larger share of the population (14% in 2006, projected to rise to 20% by 2021). The Canadian Longitudinal Study on Aging (CLSA) is a national longitudinal study of adult development and aging that will recruit 50,000 Canadians aged 45 to 85 years of age and follow them for at least 20 years. All participants will provide a common set of information concerning many aspects of health and aging, and 30,000 will undergo an additional in-depth examination coupled with the donation of biological specimens (blood and urine). The CLSA will become a rich data source for the study of the complex interrelationship among the biological, physical, psychosocial, and societal factors that affect healthy aging. © 2009 Canadian Association on Gerontology.

Organizational assessment in paediatric primary care:Development and initial validation of the primary care organizational questionnaire

Primary care in the United States is undergoing many changes. Reliable and valid instruments are needed to assess the effects of these changes. The Primary Care Organizational Questionnaire (PCOQ), a 56-item 5-point Likert scale survey that evaluates interactions among members of the clinic/practice and job-related attributes, was administered to clinicians and staff in 36 primary care practices serving paediatric populations in Connecticut. A priori scales were reliable (Cronbach alpha =0.7). Analysis of variance (ANOVA) showed greater heterogeneity across clinics than within clinics for 13 of 15 a priori scales, which were then included in a principal component factor analysis with varimax rotation. Eigenvalue analysis showed nine significant factors, largely similar to the a priori scales, indicating concurrent construct validity. Further research will ascertain the utility of the PCOQ in predicting the effectiveness of primary care practices in implementing disease management programmes. © 2006 Royal Society of Medicine Press.

Development and Validation of a PulseNet Standardized Protocol for Subtyping Isolates of Cronobacter Species

Cronobacter (formerly known as Enterobacter sakazakii) is a genus comprising seven species regarded as opportunistic pathogens that can be found in a wide variety of environments and foods, including powdered infant formula (PIF). Cronobacter sakazakii, the major species of this genus, has been epidemiologically linked to cases of bacteremia, meningitis in neonates, and necrotizing enterocolitis, and contaminated PIF has been identified as an important source of infection. Robust and reproducible subtyping methods are required to aid in the detection and investigation, of foodborne outbreaks. In this study, a pulsed-field gel electrophoresis (PFGE) protocol was developed and validated for subtyping Cronobacter species. It was derived from an existing modified PulseNet protocol, wherein XbaI and SpeI were the primary and secondary restriction enzymes used, generating an average of 14.7 and 20.3 bands, respectively. The PFGE method developed was both reproducible and discriminatory for subtyping Cronobacter species.

Role of vascular endothelial growth factor and placental growth factors during retinal vascular development and hyaloid regression

PURPOSE. Vascular endothelial growth factor (VEGF)-A and placental growth factor (PIGF) are members of a large group of homologous peptides identified as the VEGF family. Although VEGF-A is known to act as a potent angiogenic peptide in the retina, the vasoactive function of PIGF in this tissue is less well defined. This study has sought to elucidate the expression patterns and modulatory role of these growth factors during retinal vascular development and hyaloid regression in the neonatal mouse. METHODS. C57BL6J mice were killed at postnatal days (P)1, P3, P5, P7, P9, and P11. The eyes were enucleated and processed for in situ hybridization and immunocytochemistry and the retinas extracted for total protein or RNA. Separate groups of neonatal mice were also injected intraperitoneally daily from P2 through P9 with either VEGF-neutralizing antibody, PIGF-neutralizing antibody, isotype immunoglobulin (Ig)-G, or phosphate-buffered saline (PBS). The mice were then perfused with fluorescein isothiocyanate (FITC)-dextran, and the eyes were subsequently embedded in paraffin wax or flat mounted. RESULTS. Quantitative (real-time) reverse transcription-polymerase chain reaction (RT-PCR) demonstrated similar expression patterns of VEGF-A and PIGF mRNA during neonatal retinal development, although the fluctuation between time periods was greater overall for VEGF-A. The localization of VEGF-A and PIGF in the retina, as revealed by in situ hybridization and immunohistochemistry, was also similar. Neutralization of VEGF-A caused a significant reduction in the hyaloid and retinal vasculature, whereas PIGF antibody treatment caused a marked persistence of the hyaloid without significantly affecting retinal vascular development. CONCLUSIONS. Although having similar expression patterns in the retina, these growth factors appear to have distinct modulatory influences during normal retinal vascular development and hyaloid regression.

Accumulation of Maillard reaction products in skin collagen in diabetes and aging

To investigate the contribution of glycation and oxidation reactions to the modification of insoluble collagen in aging and diabetes, Maillard reaction products were measured in skin collagen from 39 type 1 diabetic patients and 52 nondiabetic control subjects. Compounds studied included fructoselysine (FL), the initial glycation product, and the glycoxidation products, N epsilon-(carboxymethyl) lysine (CML) and pentosidine, formed during later Maillard reactions. Collagen-linked fluorescence was also studied. In nondiabetic subjects, glycation of collagen (FL content) increased only 33% between 20 and 85 yr of age. In contrast, CML, pentosidine and fluorescence increased five-fold, correlating strongly with age. In diabetic patients, collagen FL was increased threefold compared with nondiabetic subjects, correlating strongly with glycated hemoglobin but not with age. Collagen CML, pentosidine and fluorescence were increased up to twofold in diabetic compared with control patients: this could be explained by the increase in glycation alone, without invoking increased oxidative stress. There were strong correlations among CML, pentosidine and fluorescence in both groups, providing evidence for age-dependent chemical modification of collagen via the Maillard reaction, and acceleration of this process in diabetes. These results support the description of diabetes as a disease characterized by accelerated chemical aging of long-lived tissue proteins.

Effect of diabetes and aging on carboxymethyllysine levels in human urine

Carboxymethyllysine (CML) has been identified as a modified amino acid that accumulates with age in human lens proteins and collagen. CML may be formed by oxidation of fructoselysine (FL), the Amadori adduct formed on nonenzymatic glycosylation of lysine residues in protein, or by reaction of ascorbate with protein under autoxidizing conditions. We proposed that measurements of tissue and urinary CML may be useful as indices of oxidative stress or damage to proteins in vivo. To determine the extent to which oxidation of nonenzymatically glycosylated proteins contributes to urinary CML, we measured the urinary concentrations of FL and CML in diabetic (n = 26) and control (n = 28) patients. The urinary concentration of FL correlated strongly with HbA1 measurements and was significantly higher in diabetic compared with control samples (9.2 +/- 6.5 and 4.0 +/- 2.8 micrograms/mg creatinine, respectively; P less than 0.0001). There was also a strong correlation between the concentrations of CML and FL in both diabetic and control urine (r = 0.67, P less than 0.0001) but only a weakly significant increase in the CML concentration in diabetic compared with control urine (1.2 +/- 0.5 and 1.0 +/- 0.3 micrograms/mg creatinine, respectively; P = 0.05). The molar ratio of CML to FL was significantly lower in diabetic compared with control patients (0.25 +/- 0.12 and 0.43 +/- 0.16, respectively; P less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)