19 resultados para Vitreous humor.
em Queensland University of Technology - ePrints Archive
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In an attempt to generate supramolecular assemblies able to function as self-healing hydrogels, a novel ureido-pyrimidinone (UPy) monomer, 2-(N ′-methacryloyloxyethylureido)-6-(1-adamantyl)-4[1H]-pyrimidinone, was synthesized and then copolymerized with N,N-dimethylacrylamide at four different feed compositions, using a solution of lithium chloride in N,N-dimethylacetamide as the polymerization medium. The assembling process in the resulting copolymers is based on crosslinking through the reversible quadruple hydrogen bonding between side-chain UPy modules. The adamantyl substituent was introduced in order to create a “hydrophobic pocket” that may protect the hydrogen bonds against the disruptive effect of water molecules. Upon hydration to equilibrium, all copolymers generated typical hydrogels when their concentration in the hydrated system was at least 15%. The small-deformation rheometry showed that all hydrated copolymers were hydrogels that maintained a solid-like behavior, and that their extrusion through a syringe needle did not affect significantly this behavior, suggesting a self-healing capacity in these materials. An application as injectable substitutes for the eye's vitreous humor was proposed
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Development of an effective preservation strategy to fulfill off-the-shelf availability of tissue-engineered constructs (TECs) is demanded for realizing their clinical potential. In this study, the feasibility of vitrification, ice-free cryopreservation, for precultured ready-to-use TECs was evaluated. To prepare the TECs, bone marrow-derived porcine mesenchymal stromal cells (MSCs) were seeded in polycaprolactone-gelatin nanofibrous scaffolds and cultured for 3 weeks before vitrification treatment. The vitrification strategy developed, which involved exposure of the TECs to low concentrations of cryoprotectants followed by a vitrification solution and sterile packaging in a pouch with its subsequent immersion directly into liquid nitrogen, was accomplished within 11min. Stepwise removal of cryoprotectants, after warming in a 38 degrees C water bath, enabled rapid restoration of the TECs. Vitrification did not impair microstructure of the scaffold or cell viability. No significant differences were found between the vitrified and control TECs in cellular metabolic activity and proliferation on matched days and in the trends during 5 weeks of continuous culture postvitrification. Osteogenic differentiation ability in vitrified and control groups was similar. In conclusion, we have developed a time- and cost-efficient cryopreservation method that maintains integrity of the TECs while preserving MSCs viability and metabolic activity, and their ability to differentiate.
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During the coverage of breaking news and broadcasts on social media, journalists and audiences alike share links, comments, and opinions in response to new developments. On Twitter, such content can gain increased visibility by receiving retweets from other users, through automated functions, or by manually republishing and modifying comments. This article studies tweeted coverage of the doping scandal involving Lance Armstrong in 2012 and 2013. Humorous framing is found to be popular in this discussion, and such comments experience different longevity to breaking news tweets. With these patterns come new opportunities for users to modify and appropriate punch lines in attempts to receive increased attention—and for the serendipitous creation of similar jokes—which raise questions of authorship and attribution.
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This study sought to improve understanding of the persuasive process of emotion-based appeals not only in relation to negative, fear-based appeals but also for appeals based upon positive emotions. In particular, the study investigated whether response efficacy, as a cognitive construct, mediated outcome measures of message effectiveness in terms of both acceptance and rejection of negative and positive emotion-based messages. Licensed drivers (N = 406) participated via the completion of an on-line survey. Within the survey, participants received either a negative (fear-based) appeal or one of the two possible positive appeals (pride or humor-based). Overall, the study's findings confirmed the importance of emotional and cognitive components of persuasive health messages and identified response efficacy as a key cognitive construct influencing the effectiveness of not only fear-based messages but also positive emotion-based messages. Interestingly, however, the results suggested that response efficacy's influence on message effectiveness may differ for positive and negative emotion-based appeals such that significant indirect (and mediational) effects were found with both acceptance and rejection of the positive appeals yet only with rejection of the fear-based appeal. As such, the study's findings provide an important extension to extant literature and may inform future advertising message design.
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This is a review of "Capitalism, socialism, and democracy", by Joseph A. Schumpeter, New York, Harper Perennial, 1942 (first Harper Colophon edition published 1975). "The public mind has by now so thoroughly grown out of humor with it as to make condemnation of capitalism and all its works a foregone conclusion – almost a requirement of the etiquette of discussion. Whatever his political preference, every writer or speaker hastens to conform to this code and to emphasize his critical attitude, his freedom from ‘complacency’, his belief in the inadequacies of capitalist achievement, his aversion to capitalist and his sympathy with anti-capitalist interests. Any other attitude is voted not only foolish but anti-social and is looked upon as an indication of immoral servitude." We might easily mistake this for a voice weary of contemplating the implications for neo-liberal nostrums of our current global financial crisis were it not for the rather formal, slightly arch, style and the gender exclusive language. It was in fact penned in the depths of World War II by Harvard economist Joseph Schumpeter, who fell off the map only to re-emerge from the 1970s as oil shocks and stagflation in the west presaged the decline of the Keynesian settlement, as east Asian newly industrialising economies were modelling on his insistence that entrepreneurialism, access to credit and trade were the pillars of economic growth, and as innovation became more of a watchword for post-industrial economies in general. The second coming was perhaps affirmed when his work was dubbed by Forbes in 1983 – on the occasion of the 100th anniversary of the birth of both men – as of greater explanatory import than Keynes’. (And what of our present resurgent Keynesian moment?)...
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Purpose: To investigate the influence of accommodation upon axial length (and a comprehensive range of ocular biometric parameters), in populations of young adult myopic and emmetropic subjects. Methods: Forty young adult subjects had ocular biometry measured utilizing a non-contact optical biometer (Lenstar LS 900) based upon the principle of optical low coherence reflectometry, under three different accommodation demands (0 D, 3 D and 6 D). Subjects were classified as emmetropes (n=19) or myopes (n=21) based upon their spherical equivalent refraction (mean emmetropic refraction -0.05 ± 0.27DS and mean myopic refraction -1.82 ± 0.84 DS). Results: Axial length changed significantly with accommodation, with a mean increase of 11.9 ± 12.3 µm and 24.1 ± 22.7 µm for the 3 D and 6 D accommodation stimuli respectively. A significant axial elongation associated with accommodation was still evident even following correction of the axial length data for potential error due to lens thickness change. The mean ‘corrected’ increase in axial length was 5.2 ± 11.2 µm, and 7.4 ± 18.9 µm for the 3 D and 6 D stimuli respectively. There was no significant difference between the myopic and emmetropic populations in terms of the magnitude of change in axial length with accommodation, regardless of whether the data were corrected or not. A number of other ocular biometric parameters, such as anterior chamber depth, lens thickness and vitreous chamber depth also exhibited significant change with accommodation. The myopic and emmetropic populations also exhibited no significant difference in the magnitude of change in these parameters with accommodation. Conclusions: The eye undergoes a significant axial elongation associated with a brief period of accommodation, and the magnitude of this change in eye length increases for larger accommodation demands, however there is no significant difference in the magnitude of eye elongation in myopic and emmetropic subjects.
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Teaching is emotional work. This is especially the case in the first years of teaching when new teachers are particularly vulnerable. By understanding changes in teacher emotions in the early years of teaching we hope to identify strategies that might ultimately reduce teacher attrition. As part of a larger study of the transition of new teachers to the profession, this ethnographic case study explores how a new science teacher produced and reproduced positive emotional interaction rituals with her students in her first year of teaching. We show how dialogical interactions were positive and satisfying experiences for the teacher, and how they were reproduced successfully in different contexts. We also illustrate how both teacher and students used humor to create a structure for dialogical interactions. During these successful interactions the students used shared resources to satisfy their teacher that they were engaging in the relevant science content. The implications of what we have learned for the professional development of new teachers are discussed in relation to an expanded understanding of teacher emotions.
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"Bollywood Extras" has been described as a bit like Vladimir Nabokov's "Lolita" (1955) meets Nathanael West's "Day of the Locust" (1939). Unlike those two classics, this new novel by Dr D. Bruno Starrs is set in 21st Century India's Hindi-language film industry epicenter known as 'Bollywood', Mumbai's answer to America's 'Hollywood'. And there is another major difference: the story (i.e. the narrative interaction between an American Extras Casting Agent, 'Dr Arden Pyle', an under-age wannabe Bollywood starlet, 'Chandy', and the despicable but wealthy Indian man who stalks her, 'Ishmail'), is all staged against a backdrop of rabid religious terrorism. Written with the unique black comedic and literary flair Dr D. Bruno Starrs is renown for, this, his 3rd full-length novel, boldly captures the feel of Mumbai and the small-time players in its big-time film industry, with style, humor and originality. Tom Flood, winner of the Miles Franklin Literary Award and founder of Flood Manuscripts, said this of the novel's second last draft: "What is best about 'Bollywood Extras' will likely be its albatross in the sliced bread world of mainstream publishing. Three strengths that make the work what it is - the length, the style, the intellectual capital - will be three strikes against it when it comes to the money. While I delight in rich language and agile invention, I've given you the reasons the trade ('legit') presses won't take 'Bollywood Extras'. Do I think you should you change it? No. I like it. Why ruin an interesting work for money?" As a professional assessor, Flood did, of course, offer many suggestions and these were duly implemented, although the author steadfastly adhered to the style he had already cemented, thus not changing in anyway what Flood refers to as its three strengths. Dr Starrs knew (having accessed Flood's professional services previously) that a 'Thumbs Up' from the best manuscript assessor in the country meant that Bollywood Extras was ready to be birthed. So, here it is: Dr Starrs has delivered his 3rd baby and 'christened' it "Bollywood Extras"!
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For decades the prevailing idea in B2B marketing has been that buyers are motivated by product/service specifications. Sellers are put on approved supplier lists, invited to respond to RFPs, and are selected on the basis of superior products, at the right price, delivered on time. The history of B2B advertising is filled with the advice “provide product specifications” and your advertising will be noticed, lead to sales inquiries, and eventually result in higher sales. Advertising filled with abstractions might work in the B2C market, but the B2B marketplace is about being literal. What we know about advertising — and particularly the message component of advertising — is based on a combination of experience, unproven ideas and a bit of social science. Over the years, advertising guidelines produced by the predecessors of BMA (National Industrial Advertising Association, Association of Industrial Advertising, and the Business/Professional Advertising Association) stressed emphasizing product features and tangible benefits. The major publishers of B2B magazines, e.g., McGraw-Hill, Penton Publishing, et al. had similar recommendations. Also, B2B marketing books recommend advertising that focuses on specific product features (Kotler and Pfoertsch, 2006; Lamons, 2005). In more recent times, abstraction in advertising messages has penetrated the B2B marketplace. Even though such advertising legends as David Ogilvy (1963, 1985) frequently recommended advertising based on hard-core information, we’ve seen the growing use of emotional appeals, including humor, fear, parental affection, etc. Beyond the use of emotion, marketers attempt to build a stronger connection between their brands and buyers through the use of abstraction and symbolism. Below are two examples of B2B advertisements — Figure 1A is high in literalism and Figure 1B is high in symbolism. Which approach — a “left-brain” (literal) or “right brain” (symbolic) is more effective in B2B advertising? Are the advertising message creation guidelines from the history of B2B advertising accurate? Are the foundations of B2B message creation (experience and unproven ideas) sound?
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It is well known that a broad range of ocular anatomical and physiological parameters undergo significant diurnal variation. However, the natural diurnal variations that occur in the length of the human eye (axial length) and their underlying causes have been less well studied. Improvements in optical methods for the measurement of ocular biometrics now allow more precise and comprehensive measurements of axial length to be performed than has previously been possible. Research from animal models also suggests a link between diurnal axial length variations and longer term myopic eye growth, and that retinal image defocus can disrupt these diurnal rhythms in axial length. This research programme has examined the diurnal variations in axial length in young normal eyes, the contributing components and the influence of optical stimuli on these changes. In the first experiment, the normal pattern and consistency of the diurnal variations in axial length were examined at 10 different times (5 measurements each day, at ~ 3-hour intervals from ~ 9 am to ~ 9 pm) over 2 consecutive days on 30 young adult subjects (15 myopes, 15 emmetropes). Additionally, variations in a range of other ocular biometric measurements such as choroidal thickness, intraocular pressure, and other ocular biometrics were also explored as potential factors that may be associated with the observed variations in axial length. To investigate the potential influence of refractive error on diurnal axial length variations, the differences in the magnitude and pattern of diurnal variations in axial length between the myopic and emmetropic subjects were examined. Axial length underwent significant diurnal variation that was consistently observed over the 2 consecutive days of measurements, with the longest axial length typically occurring during the day, and the shortest at night. Significant diurnal variations were also observed in choroidal thickness, IOP and other ocular biometrics (such as central corneal thickness, anterior chamber depth and vitreous chamber depth) of the eye. Diurnal variations in vitreous chamber depth, IOP (positive associations) and choroidal thickness (negative association) were all significantly correlated with the diurnal changes in axial length. Choroidal thickness was found to fluctuate approximately in antiphase to the axial length changes, with the average timing of the longest axial length coinciding with the thinnest choroid and vice versa. There were no significant differences in the ocular diurnal variations associated with refractive error. Given that the diurnal changes in axial length could be associated with the changes in the eye’s optical quality, whether the optical quality of the eye also undergoes diurnal variation in the same cohort of young adult myopes and emmetropes over 2 consecutive days was also examined. Significant diurnal variations were observed only in the best sphere refraction (power vector M) and in the spherical aberration of the eye over two consecutive days of testing. The changes in the eyes lower and higher order ocular optics were not significantly associated with the diurnal variations in axial length and the other measured ocular biometric parameters. No significant differences were observed in the magnitude and timing of diurnal variations in lower-order and higher-order optics associated with refractive error. Since the small natural fluctuations in the eye’s optical quality did not appear to be sufficient to influence the natural diurnal fluctuations in ocular biometric parameters, in the next experiment, the influence of monocular myopic defocus (+1.50 DS) upon the normal diurnal variations in axial length and choroidal thickness of young adult emmetropic human subjects (n=13) imposed over a 12 hour period was examined. A series of axial length and choroidal thickness measurements (collected at ~3 hourly intervals, with the first measurement at ~9 am and the final measurement at ~9 pm) were obtained over three consecutive days. The natural diurnal rhythms (Day 1, no defocus), diurnal rhythms with monocular myopic defocus (Day 2, +1.50 DS spectacle lens over the right eye), and the recovery from any defocus induced changes (Day 3, no defocus) were examined. Significant diurnal variations over the course of the day were observed in both axial length and choroidal thickness on each of the three measurement days. The introduction of monocular myopic defocus led to significant reductions in the mean amplitude of diurnal change, and phase shifts in the peak timing of the diurnal rhythms in axial length and choroidal thickness. These defocus induced changes were found to be transient in nature and returned to normal the day following removal of the defocus. To further investigate the influence of optical stimuli on human diurnal rhythms, in the final experiment, the influence of monocular hyperopic defocus on the normal diurnal rhythms in axial length and choroidal thickness was examined in young adult emmetropic subjects (n=15). Similar to the previous experiment, the natural diurnal rhythms (Day 1, no defocus), diurnal rhythms with monocular hyperopic defocus (Day 2, -2.00 DS spectacle lens over the right eye), and the recovery from any defocus induced changes (Day 3, no defocus) were examined over three consecutive days. Both axial length and choroidal thickness underwent significant diurnal variations on each of the three days. The introduction of monocular hyperopic defocus resulted in a significant increase in the amplitude of diurnal change, but no change in the peak timing of diurnal rhythms in both parameters. The ocular changes associated with hyperopic defocus returned to normal, the day following removal of the defocus. This research has shown that axial length undergoes significant diurnal variation in young adult human eyes, and has shown that the natural diurnal variations in choroidal thickness and IOP are significantly associated, and may underlie these diurnal fluctuations in axial length. This work also demonstrated for the first time that exposing young human eyes to monocular myopic and hyperopic defocus leads to a significant disruption in the normal diurnal rhythms of axial length and choroidal thickness. These changes in axial length with defocus may reflect underlying mechanisms in the human eye that are involved in the regulation of longer term eye growth.
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Purpose: In animal models hemi-field deprivation results in localised, graded vitreous chamber elongation and presumably deprivation induced localised changes in retinal processing. The aim of this research was to determine if there are variations in ERG responses across the retina in normal chick eyes and to examine the effect of hemi-field and full-field deprivation on ERG responses across the retina and at earlier times than have previously been examined electrophysiologically. Methods: Chicks were either untreated, wore monocular full-diffusers or half-diffusers (depriving nasal retina) (n = 6-8 each group) from day 8. mfERG responses were measured using the VERIS mfERG system across the central 18.2º× 16.7º (H × V) field. The stimulus consisted of 61 unscaled hexagons with each hexagon modulated between black and white according to a pseudorandom binary m-sequence. The mfERG was measured on day 12 in untreated chicks, following 4 days of hemi-field diffuser wear, and 2, 48 and 96 h after application of full-field diffusers. Results: The ERG response of untreated chick eyes did not vary across the measured field; there was no effect of retinal location on the N1-P1 amplitude (p = 0.108) or on P1 implicit time (p > 0.05). This finding is consistent with retinal ganglion cell density of the chick varying by only a factor of two across the entire retina. Half-diffusers produced a ramped retina and a graded effect of negative lens correction (p < 0.0001); changes in retinal processing were localized. The untreated retina showed increasing complexity of the ERG waveform with development; form-deprivation prevented the increasing complexity of the response at the 2, 48 and 96 h measurement times and produced alterations in response timing. Conclusions: Form-deprivation and its concomitant loss of image contrast and high spatial frequency images prevented development of the ERG responses, consistent with a disruption of development of retinal feedback systems. The characterisation of ERG responses in normal and deprived chick eyes across the retina allows the assessment of concurrent visual and retinal manipulations in this model. (Ophthalmic & Physiological Optics © 2013 The College of Optometrists.)
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The ways we assume, observe and model “presence” and its effects are the focus in this paper. Entities with selectively shared presences are the basis of any collective, and of attributions (such as “humorous”, “efficient” or “intelligent”). The subtleties of any joint presence can markedly influence potentials, perceptions and performance of the collective as demonstrated when a humorous tale is counterpoised with disciplined thought. Disciplines build on presences assumed known or knowable while fluid and interpretable presences pervade humor. Explorations in this paper allow considerations of collectives, causality and the philosophy of computing. Economics has long considered issues of collective action in ways circumscribed by assumptions about the presence of economic entities. Such entities are deemed rational but they are clearly not intelligent. To reach its potential, collective intelligence research needs more adequate considerations of alternate presences and their impacts.
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The world of classical ballet exerts considerable physical and psychological stress upon those who participate, and yet the process of coping with such stressors is not well understood. The purpose of the present investigation was to examine relationships between coping strategies and competitive trait anxiety among ballet dancers. Participants were 104 classical dancers (81 females and 23 males) ranging in age from 15 to 35 years (M = 19.4 yr., SD = 3.8 yr.) from three professional ballet companies, two private dance schools, and two full-time, university dance courses in Australia. Participants had a mean of 11.5 years of classical dance training (SD = 5.2 yr.), having started dance training at 6.6 years of age (SD = 3.4 yr.). Coping strategies were assessed using the Modified COPE scale (MCOPE: Crocker & Graham, 1995), a 48-item measure comprising 12 coping subscales (Seeking Social Support for Instrumental Reasons, Seeking Social Support for Emotional Reasons, Behavioral Disengagement, Planning, Suppression of Competing Activities, Venting of Emotions, Humor, Active Coping, Denial, Self-Blame, Effort, and Wishful Thinking). Competitive trait anxiety was assessed using the Sport Anxiety Scale (SAS: Smith, Smoll, & Schutz, 1990), a 21-item measure comprising three anxiety subscales (Somatic Anxiety, Worry, Concentration Disruption). Standard multiple regression analyses showed that trait anxiety scores, in particular for Somatic Anxiety and Worry, were significant predictors of seven of the 12 coping strategies (Suppression of Competing Activities: R2 = 27.1%; Venting of Emotions: R2 = 23.2%; Active Coping: R2 = 14.3%; Denial: R2 = 17.7%; Self-Blame: R2 = 35.7%; Effort: R2 = 16.6%; Wishful Thinking: R2 = 42.3%). High trait anxious dancers reported more frequent use of all categories of coping strategies. A separate two-way MANOVA showed no significant main effect for gender nor status (professional versus students) and no significant interaction effect. The present findings are generally consistent with previous research in the sport psychology domain (Crocker & Graham, 1995; Giacobbi & Weinberg, 2000) which has shown that high trait anxious athletes tend, in particular, to use more maladaptive, emotion-focused coping strategies when compared to low trait anxious athletes; a tendency which has been proposed to lead to negative performance effects. The present results emphasize the need for the effectiveness of specific coping strategies to be considered during the process of preparing young classical dancers for a career in professional ballet. In particular, the results suggest that dancers who are, by nature, anxious about performance may need special attention to help them to learn to cope with performance-related stress. Given the absence of differences in coping strategies between student and professional dancers and between males and females, it appears that such educational efforts should begin at an early career stage for all dancers.
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A 60-year-old male experienced a marked unilateral myopic shift of 20 D following attempted removal of intravitreal heavy silicone oil (HSO) used in the treatment of inferior proliferative vitreous retinopathy following retinal detachment. Examination revealed HSO adherent to the corneal endothelium forming a convex interface with the aqueous, obscuring the entire pupil, which required surgical intervention to restore visual acuity. This case highlights the potential ocular complications associated with silicone oil migration into the anterior chamber, which include corneal endothelial decompensation and a significant increase in myopia.
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Purpose The present study aimed to review the effect of dehydration during Ramadan fasting on the health and ocular parameters leading to changes in eye function. Methods Articles included in the study were taken from PubMed, Ovid, Web of Science and Google Scholar up to 2014. Related articles were also obtained from scientific journals on fasting and vision system. Results Dehydration and nutrition changes in Ramadan cause an increase in tear osmolarity, ocular aberration, anterior chamber depth, IOL measurement, central corneal thickness, retinal and choroidal thicknesses, and also a decrease in IOP, tear secretion, and vitreous thickness. Conclusion Much research related to the effect of dehydration on ocular parameters during Ramadan fasting exists. The findings reveal association with significant changes on ocular parameters. Thus, it seems requisite to have a comprehensive study on "fasting and ocular parameters”, which will be helpful in making decisions and giving plan to the patients.