Search results for: Tony J. Prescott

Authors: Wenfa Yu, Thuva Gnanasampanthan, John Finlay, Jessica Clarke, Charlotte Anderson, Tony Clare, Axel Rosenhahn

Abstract:

Marine biofouling is a worldwide problem at vast economic and ecological costs. Historically it was combated with toxic coatings such as tributyltin. As those coatings being banned nowadays, finding environmental friendly antifouling solution has become an urgent topic. In this study antifouling coatings consisted of natural occurring polysaccharides hyaluronic acid (HA), alginic acid (AA), chitosan (Ch) and polyelectrolyte polyethylenimine (PEI) are constructed into polyelectrolyte multilayers (PEMs) in a Layer-by-Layer (LbL) method. LbL PEM construction is a straightforward way to assemble biomacromolecular coatings on surfaces. Advantages about PEM include ease of handling, highly diverse PEM composition, precise control over the thickness and so on. PEMs have been widely employed in medical application and there are numerous studies regarding their protein adsorption, elasticity and cell adhesive properties. With the adjustment of coating composition, termination layer charge, coating morphology and cross-linking method, it is possible to prepare low marine biofouling coatings with PEMs. In this study, using spin coating technology, PEM construction was achieved at smooth multilayers with roughness as low as 2nm rms and highly reproducible thickness around 50nm. To obtain stability in sea water, the multilayers were covalently cross-linked either thermally or chemically. The cross-linking method affected surface energy, which was reflected in water contact angle, thermal cross-linking led to hydrophobic surfaces and chemical cross-linking generated hydrophilic surfaces. The coatings were then evaluated regarding its protein resistance and biological species resistance. While the hydrophobic thermally cross-linked PEM had low resistance towards proteins, the resistance of chemically cross-linked PEM strongly depended on the PEM termination layer and the charge of the protein, opposite charge caused high adsorption and same charge low adsorption, indicating electrostatic interaction plays a crucial role in the protein adsorption processes. Ulva linza was chosen as the biological species for antifouling performance evaluation. Despite of the poor resistance towards protein adsorption, thermally cross-linked PEM showed good resistance against Ulva spores settlement, the chemically cross-linked multilayers showed poor resistance regardless of the termination layer. Marine species adhesion is a complex process, although it involves proteins as bioadhesives, protein resistance its own is not a fully indicator for its antifouling performance. The species will pre select the surface, responding to cues like surface energy, chemistry, or charge and so on. Thus making it difficult for one single factors to determine its antifouling performance. Preparing PEM coating is a comprehensive work involving choosing polyelectrolyte combination, determining termination layer and the method for cross-linking. These decisions will affect PEM properties such as surface energy, charge, which is crucial, since biofouling is a process responding to surface properties in a highly sensitive and dynamic way.

Keywords: hyaluronic acid, polyelectrolyte multilayers, protein resistance, Ulva linza zoospores

Procedia PDF Downloads 163

Authors: Tony Wilson

Abstract:

This paper sets out a practices perspective or practices theory, which has become pervasive from business to sociological studies. In doing so, it locates the perspective historically (in the work of the philosopher Heidegger) and provides a contemporary illustration of its application to communication, consumer and cultural studies as central to this conference theme. The structured account of practices (as articulated in eight ‘axioms’) presented towards the conclusion of this paper is an initial statement - planned to encourage further detailed qualitative and systematic research in areas of interest to the conference. Practice theories of equipped and situated construction of participatory meaning (as in media and marketing consuming) are frequently characterized as lacking common ground, or core principles. This paper explores whether by retracing a journey to earlier philosophical underwriting, a shared territory promoting new research can be located as current philosophical hermeneutics. Moreover, through returning to hermeneutic first principles, the paper shows that a series of spatio-temporal metaphors become available - appropriate to analyzing communication as a process across disciplines in which it is considered. Thus one can argue, for instance, that media users engage (enter) digital text from their diverse ‘horizons of expectation’, in a productive enlarging ‘fusion’ of horizons of understanding, thereby ‘projecting’ a new narrative, integrated in a ‘hermeneutic circle’ of meaning. A politics of communication studies may contest a horizon of understanding - so engaging in critical ‘distancing’. Marketing’s consumers can occupy particular places on a horizon of understanding. Media users pass over borders of changing, revised perspectives. Practices research can now not only be discerned in multiple disciplines but equally crosses disciplines. The ubiquitous practice of media use by managers and visitors in a shopping mall - the mediatization of malls - responds to investigating not just with media study expertise, but from an interpretive marketing perspective. How have mediated identities of person or place been changed? Emphasizing understanding of entities in a material environment as ‘equipment’, practices theory enables the quantitative correlation of use and demographic variable as ‘Zeug Score’. Human behavior is fundamentally habitual - shaped by its tacit assumptions - occasionally interrupted by reflection. Practices theory acknowledges such action to be minimally monitored yet nonetheless considers it as constructing narrative. Thus presented in research, ‘storied’ behavior can then be seen to be (in)formed and shaped from a shifting hierarchy of ‘horizons’ or of perspectives - from habituated to reflective - rather than a single seamless narrative. Taking a communication practices perspective here avoids conflating tacit, transformative and theoretical understanding in research. In short, a historically grounded and unifying statement of contemporary practices theory will enhance its potential as a tool in communication, consumer and cultural research, landscaping interpretative horizons of human behaviour through exploring widely the culturally (in)formed narratives equipping and incorporated (reflectively, unreflectively) in people’s everyday lives.

Keywords: communication, consumer, cultural practices, hermeneutics

Procedia PDF Downloads 268

Authors: May Bazzi, Shafik Tokmaj, Younes Saberi, Mats Geijer, Tony Jurkiewicz, Patrik Sund, Anna Bjällmark

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Mobile radiography, employing portable X-ray equipment, has become a routine procedure within hospital settings, with chest X-rays in intensive care units standing out as the most prevalent mobile X-ray examinations. This approach is not limited to hospitals alone, as it extends its benefits to imaging patients in various settings, particularly those too frail to be transported, such as elderly care residents in nursing homes. Moreover, the utility of mobile X-ray isn't confined solely to traditional healthcare recipients; it has proven to be a valuable resource for vulnerable populations, including the homeless, drug users, asylum seekers, and patients with multiple co-morbidities. Mobile X-rays reduce patient stress, minimize costly hospitalizations, and offer cost-effective imaging. While studies confirm its reliability, further research is needed, especially regarding image quality. Recent advancements in lightweight equipment with enhanced battery and detector technology provide the potential for nearly handheld radiography. The main aim of this study was to evaluate a new lightweight mobile X-ray system with two different detectors and compare the image quality with a modern stationary system. Methods: A total of 74 images of the chest (chest anterior-posterior (AP) views and chest lateral views) and pelvic/hip region (AP pelvis views, hip AP views, and hip cross-table lateral views) were acquired on a whole-body phantom (Kyotokagaku, Japan), utilizing varying image parameters. These images were obtained using a stationary system - 18 images (Mediel, Sweden), a mobile X-ray system with a second-generation detector - 28 images (FDR D-EVO II; Fujifilm, Japan) and a mobile X-ray system with a third-generation detector - 28 images (FDR D-EVO III; Fujifilm, Japan). Image quality was assessed by visual grading analysis (VGA), which is a method to measure image quality by assessing the visibility and accurate reproduction of anatomical structures within the images. A total of 33 image criteria were used in the analysis. A panel of two experienced radiologists, two experienced radiographers, and two final-term radiographer students evaluated the image quality on a 5-grade ordinal scale using the software Viewdex 3.0 (Viewer for Digital Evaluation of X-ray images, Sweden). Data were analyzed using visual grading characteristics analysis. The dose was measured by the dose-area product (DAP) reported by the respective systems. Results: The mobile X-ray equipment (both detectors) showed significantly better image quality than the stationary equipment for the pelvis, hip AP and hip cross-table lateral images with AUCVGA-values ranging from 0.64-0.92, while chest images showed mixed results. The number of images rated as having sufficient quality for diagnostic use was significantly higher for mobile X-ray generation 2 and 3 compared with the stationary X-ray system. The DAP values were higher for the stationary compared to the mobile system. Conclusions: The new lightweight radiographic equipment had an image quality at least as good as a fixed system at a lower radiation dose. Future studies should focus on clinical images and consider radiographers' viewpoints for a comprehensive assessment.

Keywords: mobile x-ray, visual grading analysis, radiographer, radiation dose

Procedia PDF Downloads 64

Authors: Keyvan Molanorouzi, Selina Khoo, Tony Morris

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In recent years, there has been a decline in physical activity among adults. Motivation has been shown to be a crucial factor in maintaining physical activity. The purpose of this study was to whether PA motives measured by the Physical Activity and Leisure Motivation Scale PALMS predicted actual amount of PA at a later time to provide evidence for the construct validity of the PALMS. A quantitative, cross-sectional descriptive research design was employed. The Demographic Form, PALMS, and International Physical Activity Questionnaire Short form (IPAQ-S) questionnaires were used to assess motives and amount for physical activity in adults on two occasions. A sample of 640 (489 male, 151 female) undergraduate students aged 18 to 25 years (mean ±SD; 22.30±8.13 years) took part in the study. Male participants were divided into three types of activities, namely exercise, racquet sport, and team sports and female participants only took part in one type of activity, namely team sports. After 14 weeks, all 640 undergraduate students who had filled in the initial questionnaire (Occasion 1) received the questionnaire via email (Occasion 2). Of the 640 students, 493 (77%; 378 males, 115 females) emailed back the completed questionnaire. The results showed that not only were pertinent sub-scales of PALMS positively related to amount of physical activity, but separate regression analyses showed the positive predictive effect of PALMS motives for amount of physical activity for each type of physical activity among participants. This study supported the construct validity of the PALMS by showing that the motives measured by PALMS did predict amount of PA. This information can be obtained to match people with specific sport or activity which in turn could potentially promote longer adherence to the specific activity.Methods: A quantitative, cross-sectional descriptive research design was employed. The Demographic Form, PALMS, and International Physical Activity Questionnaire Short form (IPAQ-S) questionnaires were used to assess motives and amount for physical activity in adults on two occasions. A sample of 640 (489 male, 151 female) undergraduate students aged 18 to 25 years (mean ±SD; 22.30±8.13 years) took part in the study. Male participants were divided into three types of activities, namely exercise, racquet sport, and team sports and female participants only took part in one type of activity, namely team sports. After 14 weeks, all 640 undergraduate students who had filled in the initial questionnaire (Occasion 1) received the questionnaire via email (Occasion 2). Of the 640 students, 493 (77%; 378 males, 115 females) emailed back the completed questionnaire. Results: The results showed that not only were pertinent sub-scales of PALMS positively related to amount of physical activity, but separate regression analyses showed the positive predictive effect of PALMS motives for amount of physical activity for each type of physical activity among participants. This study supported the construct validity of the PALMS by showing that the motives measured by PALMS did predict amount of PA. Conclusion: This information can be obtained to match people with specific sport or activity which in turn could potentially promote longer adherence to the specific activity.

Keywords: physical activity, motivation, level of physical activity, type of physical activity

Procedia PDF Downloads 469

Authors: Mohamed Ahmed Tony, Mohamed Hamoud

Abstract:

The present study was conducted to determine the effect of commercially coated slow-release sodium butyrate (CM3000®) as a feed additive on zootechnical performance, immune status and Clostridium perfringens severity after experimental infection. Three hundred 1-d-old broiler chicks (Cobb 500) were randomly distributed into 3 treatment groups (4 replicates each) using 25 chicks per replicate on floor pens. Control (C) birds were offered non-supplemented basal diets. Treatments 1 and 2 (T1 and T2) were fed diets containing CM3000® at 300 and 500 g/ton feed, respectively, during the entire experimental period (35 days). Feed and water were offered ad-libitum. Feed consumption and body weight were recorded weekly to calculate body weight gain and feed conversion. Blood samples were collected to evaluate the immune status of the birds against Newcastle disease vaccines using HI test. At the end of the experimental period, 20 birds were chosen randomly from each group (5 birds from each pen) to compare carcass yield. At day 16 of age 20 birds from each group (5 birds/replicate) were bacteriologically examined and proved to be free from Clostridium perfringens. The isolated birds were challenged orally with 1 ml buffer containing 106 CFU/ml Clostridium perfringens local isolate and prepared from necrotic enteritis (NE) diseased farms. Birds were observed on a regular basis daily for any signs of NE. Birds that died in the challenged group were necropsied to determine the cause of death. On day 28 of age, the surviving chickens were killed by cervical dislocation and necropsied immediately. Intestinal tracts were removed and intestinal lesions were scored. Tissue samples of the duodenum, jejunum, ileum and cecum for histopathological examination were collected. All collected data were statistically analyzed using IBM SPSS® version 19 software for personal computers. Means were compared by one-way ANOVA (P<0.05) followed by the Duncan Post Hoc test. The results revealed that body weight gain was significantly (P<0.05) improved in chicks fed on both doses of CM3000® compared to the control one. Final body weight gain in T1 and T2 were 2064.94 and 2141.37 g/bird, respectively, while in the control group, the weight gain showed 1952.78 g/bird. In addition, supplementation of diets with CM3000® increased significantly feed intake (P<0.05). Total feed intake in T1 and T2 were 3186.32 and 3273.29 g/bird, respectively; however, feed intake in the control group recorded 3081.95 g/bird. The best feed conversion was recorded in T2 group (1.53). Feed conversion in the control and T1 groups were 1.58 and 1.54, respectively. Dressing percentage, liver weights and the other carcasses yields were not different between treatments. The butyrate significantly enhanced immune responses measured against Newcastle disease vaccines. Sodium butyrate significantly reduced NE lesions and healthy improved the intestinal tissues in the samples collected from T1 and T2-challenged chickens versus those collected from the control group. In conclusion, exogenous administration of slow-release butyrate (CM3000®) is capable of improving performance, enhancing immunity and NE disease resistance in broiler chickens.

Keywords: sodium butyrate, broiler chicken, zootechnical performance, immunity, necrotic enteritis

Procedia PDF Downloads 81