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1
Dark-Freudeman, Alissa. "Memory-related possible selves exploring age-related differences /". [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0005642.
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2
van, Otterdijk Sanne Dorien. "The role of age-related DNA methylation in the development of age-related disease". Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/2337.
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Alterations in DNA methylation can have dramatic effects on gene transcription, and in particular, hypermethylation of promoter associated CpG islands is known to lead to gene inactivation. Altered patterns of DNA methylation play a key role in the development of cancer and may also play important roles in many other diseases. However, the mechanisms which lead to these changes in DNA methylation are unknown. DNA methylation patterns have also been found to change during normal ageing and these changes have similarities to those that occur during the development of cancer. This suggests that for some age-related diseases, most notably cancer, altered patterns of methylation may be an early initiating event and that disease may develop in cells which already possess changes in their DNA methylation landscape. Therefore, this study was designed to examine how methylation levels at a group of genes alters over the life-course and how these relate to methylation changes observed in major age-related diseases (cancer, specifically acute lymphoblastic leukaemia (ALL) and Hereditary Nonpolyposis Colorectal Cancer (HNPCC) patients, and atherosclerosis). DNA was collected from healthy volunteers from different ages and from ALL, HNPCC and atherosclerosis patients. Methylation was quantified using pyrosequencing. The study produced a number of findings: 1) Genes exhibiting variable methylation in PBL samples from healthy volunteers are also highly methylated in leukaemia, suggesting a common underlying mechanism. 2) Increased methylation levels were observed in lymphoid compared to myeloid cells, in healthy individuals, mirroring the patterns seen in leukaemia. 3) A subset of genes exhibiting variable methylation in PBL samples from healthy volunteers and that are highly methylated in leukaemia are aberrantly methylated in HNPCC patients and atherosclerosis patients, suggesting shared risk factors. 4) While methylation levels increase during ageing, a substantial proportion of methylation is already present at birth and may thus alter disease susceptibility throughout life. 5) Blood samples from ALL patients in remission exhibit increased methylation levels (versus controls), not directly related to their leukaemic clone, and the extent of methylation correlates with overall survival. The studies to date are compatible with a hypothesis in which altered methylation of disease-related genes pre-exists in a subset of haematopoietic cells and that these cells may be at a significantly increased risk of progression to age-related diseases. Furthermore, monitoring DNA methylation may be a valuable tool for early diagnosis of these diseases, as well as for monitoring disease progression in patients.
3
Patil, Parag Ramchandra. "Age related effects of SSRIs". Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442260.
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4
Koszyca, Barbara. "Age-related changes within the knee /". Title page, contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phk86.pdf.
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Thesis (Ph. D.)--University of Adelaide, Dept. of Pathology, 1993.Attempts to understand the effects of ageing on the condition of a synovial joint. Knee joints of individuals with no known history of joint disease were examined and the pattern of cartilage damage was mapped macroscopically in a manner that allowed quantitation of the affected areas. Includes bibliographical references (leaves 267-277).
5
Despriet, Dominiek Denise Gasparine. "Genetics of age-related macular degenreation". [S.l.] : Rotterdam : [The Author] ; Erasmus University [Host], 2008. http://hdl.handle.net/1765/11512.
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6
Aydin, Senay. "Age-related deficits in perceptual stability". Thesis, Glasgow Caledonian University, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555684.
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The world's population is ageing, which represents challenges and opportunities concerning different aspects of life. Some older people exhibit various perceptual and cognitive declines, which are related to their inability to construct a stable representation of the external world, it being usually ambiguous and degraded. These declines require thorough research in order to understand their cortical mechanisms. Changes in perceptual stability as a function of ageing were explored in this PhD work using methods of psychophysics, visual evoked potentials, and eye- movement recordings. Specifically studied were attentional control in perceptual rivalry, the ability to construct a stable and efficient internal representation of degraded words and finally, saccadic suppression as an important contributory factor to the underlying perceptual stability of the visual world during saccadic eye movements. Perceptual rivalry, produced by an ambiguous Rubin vase-faces figure, was slower in older people during passive viewing than in young participants. Additionally, older adults, in contrast to young adults, were unable to hold the dominant percept longer than in passive viewing. Using current models of perceptual rivalry and studies of age-related changes in cortical activity, the increased response gain in older adults might be a possible factor leading to prolonged dominance durations in older people during passive viewing as well as impaired ability to hold the dominant percept longer. Visual evoked potentials, elicited by frequency-tagged stimulation, showed that perceptual rivalry under passive viewing caused in both age group suppression of visual evoked potentials to a contrast-modulated pattern. This finding is only true for the vase percept, when the vase percept was not dominant. Thus, the mechanism, underlying perceptual rivalry under passive viewing in early visual cortical areas, could be inhibition of neuronal populations associated with the non-dominant percept, rather than excitation of neuronal populations, corresponding to the dominant percept. Attentional control of holding the dominant percept caused an enhancement of the visual evoked potentials, representing the dominant percept, in young subjects but not in older people. Holding and switching the dominant percept also produced enhancement of gamma activity, recorded with electrodes over the occipital and parietal cortices, only in young adults. These results could be related to age-related deficits in top-down modulated attentional and figure-ground segregation processes. A novel paradigm for recognising words embedded in positional letter noise and a model for estimating internal noise components were developed. Older people showed noise-exclusion deficits when reading normal words and reversed words, but not when reading nonwords. These deficits suggest that older people may experience perceptual instability of words due to inefficient noisy perceptual representations of words. This method has the potential for use as a tool in the clinical testing of noise- exclusion deficits in normal and pathological ageing and in children with reading dysfunctions. Investigation of age-related changes in saccadic suppression revealed for the first time that older adults experienced reduced and delayed saccadic suppression compared to young adults. This could result in perceiving instability of the external world and thus affect their mobility and performance in everyday environments. The results of this thesis provide evidence of age-related deficits in the ability of older people to voluntarily perceive a stable dominant percept during perceptual rivalry, to efficiently exclude positional noise during reading degraded words and to suppress visual information during saccadic eye movements. Although these deficits involve different cortical mechanisms, the underlying cause for them could be related to impairments in inhibitory mechanisms at various cortical processing stages.
7
Scott, Jenny Louise. "Age-related changes in osteoarthritic chondrocytes". Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501074.
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Age is the most important risk factor in the development of osteoarthritis (OA). Numerous studies have now demonstrated that age-related changes occur in both the extracellular matrix and chondrocytes of OA cartilage and such changes are proposed to alter the tissue's biomechanical properties, thus predisposing to OA onset. The study presented here describes further investigation of two such age-related changes, cellular senescence and oxidative stress.
8
Badham, S. P. "Age-related changes in associative memory". Thesis, University of Warwick, 2011. http://wrap.warwick.ac.uk/50837/.
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Older adults suffer from many cognitive impairments relative to young adults and one of the most established types of age-related cognitive decline is a reduction in memory performance. Memory for single units of information (item memory) have been shown to be less susceptible to cognitive ageing than memory for associations among units of information (associative memory). An associative deficit hypothesis has been used to describe these observations as an age-related impairment in forming links between single units of information. The thesis elucidated specific differences between item and associative memory and evaluated how such differences correspond to their differential susceptibility to the effects of cognitive ageing. This indicated links between the associative deficit hypothesis and other theories of age-related memory decline, in particular, to the notion of age deficits in memory resulting from age deficits in self-initiated processing (in the absence of environmental support). Experiments 1-3 considered associative memory where the processing of associations was encouraged by distinctiveness of memory stimuli. Environmental support provided by distinctiveness was shown to improve associative memory in older adults. Experiments 4-7 considered how item and associative memory differ in their support from preexisting knowledge. Experimentally equating preexisting knowledge for item and associative memory tests eliminated the age-related associative deficit. Furthermore, it was found that preexisting knowledge could be used to enhance associative memory performance in older adults by providing support to encoding and/or retrieval processes. Experiment 8 established that item and associative memory processes were equally disrupted by a concurrent task, which indicated that both memory types are similarly affected by levels of available cognitive resources. In general, age-related associative deficits were considered to result from differing levels of environmental support for item and associative memory as opposed to a differential decline of item and associative memory processes.
9
Gu, Jiayin. "Biomarkers for Age-Related Macular Degeneration". Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1225388164.
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10
Feigl, Beatrix Karoline. "Age-related Maculopathy: A Multifocal Approach". Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16026/1/Beatrix_Feigl_Thesis.pdf.
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Age-related maculopathy (ARM) is a central retinal disease with unclear pathogenesis. It is the major cause of permanent vision loss in adults over 50 years and is increasing in prevalence and incidence, faster than the aging population would suggest. Early in the disease process (early ARM) there is little or no vision loss and there are only slight retinal changes with abnormal deposits within Bruch's membrane. As the disease progresses (late ARM or age-related macular degeneration, AMD) vision loss may be quite severe due to atrophy (dry AMD) or the development of chorioretinal neovascularisation (CNV, wet AMD). It is hard to predict from conventional eye examinations and clinical vision tests which cases will progress to the severe, dry or wet forms of the disease. Moreover, most of the conventional clinical tests are based upon subjective vision measures. Objective tests which detect ARM earlier would be a useful aid to diagnosis and to monitoring progression.
The multifocal electroretinogram (mfERG) is a relatively new clinical tool which enables the recording of electrical potentials from multiple, small areas of the central retina and thus assesses function from specific retinal locations. It is therefore useful in detecting focal retinal diseases such as hereditary or acquired maculopathies or in monitoring retinal laser or surgical treatment effects.
There is cone and rod impairment in ARM and histopathological and psychophysical evidence for a preferential vulnerability of rods compared to cones. This research project investigated if an objective tool such as the mfERG could detect early ARM,its progression and the treatment effects of multiple photodynamic therapies (PDT) on retinal function in late ARM, prior to a battery of subjective vision measures.
For comparison purposes a subjective assessment of central retinal function was performed using high and low contrast distance visual acuities (VA), near VA, low luminance VA (SKILL cards), contrast sensitivity (Pelli-Robson, P-R), saturated and desaturated Panel D-15 (sat Panel D-15, desat Panel D-15) and central visual fields (Humphrey 10-2, mean sensitivity, MS and mean defects, MD). As an objective assessment of central retinal function the cone- and rod-mediated multifocal electroretinograms were recorded.
Subjective and objective tests of retinal function were compared in early ARM and an age-matched control group (chapter 3). Seventeen eyes of seventeen subjects with early ARM and twenty control subjects with normal vision were measured. For the cone-mediated mfERG responses conventional averaging methods were used and results were correlated with subjective vision tests. The conventional cone-mediated mfERG failed to distinguish between the early ARM and control subjects whereas subjective vision measures such as HC- and LC-VA, desat Panel D-15, MS, P-R were significantly reduced in the ARM group. However, there were significant correlations between the cone-mediated mfERG and the desat Panel D-15 results in the ARM group. This suggests that the mfERG measures similar retinal processes that detect colour vision deficiency under desaturated conditions. There was no significant correlation between cone-mediated mfERG measures and funduscopic changes. The conclusion from this study was that the subjective vision tests detected early ARM better than the objective cone-mediated mfERG. Thus the aim of detecting early ARM objectively was not met by the cone-mediated mfERG suggesting the need to develop other objective tests such as a rod-mediated mfERG.
Whether the preferential rod vulnerability others have reported in early ARM could be detected by the rod-mediated mfERG was determined in the next study (chapter 4). A protocol for recording rod-mediated mfERG responses was developed by determining the optimal testing luminance to reduce the effect of stray light and elicit maximal rod-mediated responses. Sixteen of the seventeen ARM subjects and seventeen control subjects from the previous study were tested. For analysis, a customized computer template fitting method was developed in MATLAB (Mathworks, Natick, MA, USA). This method has been shown to be useful for low signal-to-noise ratio responses that characterize the rod-mediated mfERG. Significantly delayed rod-mediated mfERG responses were found whereas cone-mediated mfERG responses were within the normal range. This suggested that the effect of ARM on the rod system could be detected objectively with the rod-mediated mfERG before changes in the cone-mediated mfERG.
Which of the tests best detected progression of vision loss was investigated in chapter 5. Visual function of 26 (13 ARM and 13 control subjects) of the original 37 subjects (17 ARM and 20 control subjects) had cone- and rod-mediated mfERG and the subjective vision measures repeated after one year. The main purpose was to determine which of the tests best detected progression of vision loss. The mfERG results were analysed by using both averaged and local responses and by using the computer template fitting procedure. On average no significant worsening of either objective or subjective function measures was evident after one year. These results reinforce the slow progression of the disease. With a longer follow-up period progression of ARM may translate into measurable changes in the mfERG and the other visual function tests.
The effect of multiple photodynamic therapies (PDT) on cone- and rod-mediated function was assessed with the mfERG in the last study (chapter 6). The cumulative treatment effects of PDT in five subjects with late ARM were determined. Having demonstrated that the rod-mediated mfERG was applicable in early ARM, this study also aimed to investigate how useful it was in late ARM where there is substantially greater rod loss. Cone- and rod-mediated mfERGs, visual acuities, contrast sensitivities and central visual fields were investigated a week before treatment began and then one month after each PDT treatment. The subjects received three treatments each over an average period of five and a half months. In some subjects there were significant transient reductions in cone- and rod-mediated amplitudes possibly reflecting alterations in choroidal hypoperfusion dynamics one month after treatment. Further, b-wave component of the mfERG became increasingly misshapen after each PDT treatment suggesting an ischemic insult mainly targeting post-receptoral sites. However, objective and subjective function was stabilized after multiple PDT treatments in most of the subjects. This pilot study of five cases showed that there was no additional damage to cone- and rod-mediated outer retinal function after three PDT treatments.
One of the novel findings of this research was that the rod-mediated function measured with the mfERG was impaired in early ARM. This finding supports histopathological and psychophysical evidence of rod vulnerability in early ARM.
The results of these studies also suggest that early ARM affects different aspects of visual function which is reflected by different outcomes from objective and subjective vision tests. A model (chapter 7) based upon the results was developed proposing a hypoxic insult with a preferential alteration of post-receptoral sites in early ARM.
The cone-mediated mfERG documented the retinal damage and possible treatment effects on outer retinal function of the multiple PDTs which did not further deteriorate. Thus, this technique might assist in the development of optimal treatment modalities for ARM, especially in retreatment regimes. Greater variability was found for the rod-mediated mfERG and its clinical use in PDT treatment regimes still needs to be investigated.
In conclusion, this research has provided a better understanding of the disease process and treatment effects in ARM and might contribute to improvements in diagnosis and treatment of ARM.
11
Feigl, Beatrix Karoline. "Age-related Maculopathy: A Multifocal Approach". Queensland University of Technology, 2005. http://eprints.qut.edu.au/16026/.
Pełny tekst źródłaStreszczenie:
Age-related maculopathy (ARM) is a central retinal disease with unclear pathogenesis. It is the major cause of permanent vision loss in adults over 50 years and is increasing in prevalence and incidence, faster than the aging population would suggest. Early in the disease process (early ARM) there is little or no vision loss and there are only slight retinal changes with abnormal deposits within Bruch's membrane. As the disease progresses (late ARM or age-related macular degeneration, AMD) vision loss may be quite severe due to atrophy (dry AMD) or the development of chorioretinal neovascularisation (CNV, wet AMD). It is hard to predict from conventional eye examinations and clinical vision tests which cases will progress to the severe, dry or wet forms of the disease. Moreover, most of the conventional clinical tests are based upon subjective vision measures. Objective tests which detect ARM earlier would be a useful aid to diagnosis and to monitoring progression. The multifocal electroretinogram (mfERG) is a relatively new clinical tool which enables the recording of electrical potentials from multiple, small areas of the central retina and thus assesses function from specific retinal locations. It is therefore useful in detecting focal retinal diseases such as hereditary or acquired maculopathies or in monitoring retinal laser or surgical treatment effects. There is cone and rod impairment in ARM and histopathological and psychophysical evidence for a preferential vulnerability of rods compared to cones. This research project investigated if an objective tool such as the mfERG could detect early ARM,its progression and the treatment effects of multiple photodynamic therapies (PDT) on retinal function in late ARM, prior to a battery of subjective vision measures. For comparison purposes a subjective assessment of central retinal function was performed using high and low contrast distance visual acuities (VA), near VA, low luminance VA (SKILL cards), contrast sensitivity (Pelli-Robson, P-R), saturated and desaturated Panel D-15 (sat Panel D-15, desat Panel D-15) and central visual fields (Humphrey 10-2, mean sensitivity, MS and mean defects, MD). As an objective assessment of central retinal function the cone- and rod-mediated multifocal electroretinograms were recorded. Subjective and objective tests of retinal function were compared in early ARM and an age-matched control group (chapter 3). Seventeen eyes of seventeen subjects with early ARM and twenty control subjects with normal vision were measured. For the cone-mediated mfERG responses conventional averaging methods were used and results were correlated with subjective vision tests. The conventional cone-mediated mfERG failed to distinguish between the early ARM and control subjects whereas subjective vision measures such as HC- and LC-VA, desat Panel D-15, MS, P-R were significantly reduced in the ARM group. However, there were significant correlations between the cone-mediated mfERG and the desat Panel D-15 results in the ARM group. This suggests that the mfERG measures similar retinal processes that detect colour vision deficiency under desaturated conditions. There was no significant correlation between cone-mediated mfERG measures and funduscopic changes. The conclusion from this study was that the subjective vision tests detected early ARM better than the objective cone-mediated mfERG. Thus the aim of detecting early ARM objectively was not met by the cone-mediated mfERG suggesting the need to develop other objective tests such as a rod-mediated mfERG. Whether the preferential rod vulnerability others have reported in early ARM could be detected by the rod-mediated mfERG was determined in the next study (chapter 4). A protocol for recording rod-mediated mfERG responses was developed by determining the optimal testing luminance to reduce the effect of stray light and elicit maximal rod-mediated responses. Sixteen of the seventeen ARM subjects and seventeen control subjects from the previous study were tested. For analysis, a customized computer template fitting method was developed in MATLAB (Mathworks, Natick, MA, USA). This method has been shown to be useful for low signal-to-noise ratio responses that characterize the rod-mediated mfERG. Significantly delayed rod-mediated mfERG responses were found whereas cone-mediated mfERG responses were within the normal range. This suggested that the effect of ARM on the rod system could be detected objectively with the rod-mediated mfERG before changes in the cone-mediated mfERG. Which of the tests best detected progression of vision loss was investigated in chapter 5. Visual function of 26 (13 ARM and 13 control subjects) of the original 37 subjects (17 ARM and 20 control subjects) had cone- and rod-mediated mfERG and the subjective vision measures repeated after one year. The main purpose was to determine which of the tests best detected progression of vision loss. The mfERG results were analysed by using both averaged and local responses and by using the computer template fitting procedure. On average no significant worsening of either objective or subjective function measures was evident after one year. These results reinforce the slow progression of the disease. With a longer follow-up period progression of ARM may translate into measurable changes in the mfERG and the other visual function tests. The effect of multiple photodynamic therapies (PDT) on cone- and rod-mediated function was assessed with the mfERG in the last study (chapter 6). The cumulative treatment effects of PDT in five subjects with late ARM were determined. Having demonstrated that the rod-mediated mfERG was applicable in early ARM, this study also aimed to investigate how useful it was in late ARM where there is substantially greater rod loss. Cone- and rod-mediated mfERGs, visual acuities, contrast sensitivities and central visual fields were investigated a week before treatment began and then one month after each PDT treatment. The subjects received three treatments each over an average period of five and a half months. In some subjects there were significant transient reductions in cone- and rod-mediated amplitudes possibly reflecting alterations in choroidal hypoperfusion dynamics one month after treatment. Further, b-wave component of the mfERG became increasingly misshapen after each PDT treatment suggesting an ischemic insult mainly targeting post-receptoral sites. However, objective and subjective function was stabilized after multiple PDT treatments in most of the subjects. This pilot study of five cases showed that there was no additional damage to cone- and rod-mediated outer retinal function after three PDT treatments. One of the novel findings of this research was that the rod-mediated function measured with the mfERG was impaired in early ARM. This finding supports histopathological and psychophysical evidence of rod vulnerability in early ARM. The results of these studies also suggest that early ARM affects different aspects of visual function which is reflected by different outcomes from objective and subjective vision tests. A model (chapter 7) based upon the results was developed proposing a hypoxic insult with a preferential alteration of post-receptoral sites in early ARM. The cone-mediated mfERG documented the retinal damage and possible treatment effects on outer retinal function of the multiple PDTs which did not further deteriorate. Thus, this technique might assist in the development of optimal treatment modalities for ARM, especially in retreatment regimes. Greater variability was found for the rod-mediated mfERG and its clinical use in PDT treatment regimes still needs to be investigated. In conclusion, this research has provided a better understanding of the disease process and treatment effects in ARM and might contribute to improvements in diagnosis and treatment of ARM.
12
Collins, Michael J. "Glare recovery in age related maculopathy". Thesis, Queensland University of Technology, 1987. https://eprints.qut.edu.au/36714/6/36714_Digitised%20Thesis.pdf.
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This study has investigated the dynamics of the glare recovery process in a group of subjects with age related maculopathy (ARM) and pre-aqe related maculopathy (PARM), and compared the results of these groups with a group of age-matched controls. Glare recovery is significantly
prolonged in both age related maculopathy and pre-age related maculopathy groups in comparison to the controls. Other functional losses are also apparent in the ARM and PARM groups, including raised contrast thresholds, colour discrimination loss and a greater incidence of adaptation difficulties in changing light levels. Total glare recovery times were correlated with factors such as the presence
of pigmentary disturbance at the macula, Desaturated version of the Farnsworth Panel D-15 colour vision scores, visual acuity loss and subjective adaptation difficulties. The measurement of glare recovery is a sensitive indicator of early functional loss in the retina of subjects with early ARM and those thought to be at risk of developing
ARM (PARM).
13
Watson, Deborah J. "Colour perimetry in age related maculopathy". Thesis, Queensland University of Technology, 1994. https://eprints.qut.edu.au/36716/1/36716_Watson_1994.pdf.
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The effect of age, age related maculopathy (ARM)
and its precursor pre-age related maculopathy (PARM)
on the visual field for both white and coloured
stimuli was investigated. The visual fields were
plotted using a modified Goldmann perimeter. The
visual field was significantly reduced in size for
the white and short wavelength stimuli for the three
age groups tested. The decrease occured primarily in
the middle age group. There was no decrease in the
visual fields for the middle and long wavelength
stimuli for any of the age groups. The ARM subjects
showed no difference in visual field size for any of
the stimuli when compared to age-matched normal
subjects. The visual fields for the PARM subjects
showed no difference in visual field size for the
white, short wavelength and long wavelength
stimuli,however a decrease in visual field size for
the medium wavelength stimulus when compared with
age-matched normals was noted. The effect of pupil
size on the visual field size was also investigated.
However due to the restricted range of pupil sizes in
our subject base no definite conclusions could be
made.
14
Khouri, Leila. "Age-related declines in auditory temporal processing". Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-142166.
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15
Hogervorst, Eva. "Age-related cognitive decline and cognition enhancers". Maastricht : Maastricht : Neuropsych Publishers ; University Library, Maastricht University [Host], 1998. http://arno.unimaas.nl/show.cgi?fid=6058.
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16
Renganathan, Kutralanathan. "Oxidative stress and age related macular degeneration". online version, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1193002743.
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17
Binns, Alison Mary. "Electrophysiological investigation of age-related macular degeneration". Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/55964/.
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Age-related macular degeneration (AMD) affects 12.7 million people in Europe and North America (Klein et al., 1995 Klein et al. 1999). As a combination of decreasing birth rate and increasing longevity alter the demographic of the population, the impact of this disease can only increase. This places an immense burden, not only on the individuals afflicted by the condition, but on the financial resources of society as a whole. Unfortunately, treatment for AMD is still very restricted, and even our understanding of the pathogenesis of the disease is far from complete One concern in tackling the growing problem of AMD is that methods used in the assessment of the condition are limited, usually based on fundus appearance and visual acuity. The aim of this study was to develop a battery of electrophysiological tests which would be sensitive to the most subtle changes in retinal function in AMD. Such tests may aid diagnosis, provide a more sensitive measure of disease progression, and allow an early identification of phenotypic subtypes. Protocols were included for the recording of the focal rod ERG, the focal cone ERG, the S-cone ERG and the dynamic focal cone ERG, along with psychophysical tests of colour vision and dark adaptation. These tests were then applied to 31 subjects with ARM (12 with bilateral ARM, 11 with unilateral wet AMD and 8 with unilateral dry AMD), and 28 controls. In the analysis of ERG amplitudes a ratio of focal to full-field amplitude was introduced as a novel means of reducing intersubject variability in response. This was found to increase the accuracy of all tests in distinguishing between subject groups. The greatest separation between ARM and control groups was provided by the dynamic tests of visual function i.e. rod-cone break time of the dark adaptation function, and time constant of recovery of the dynamic focal cone ERG. The time to rod-cone break also showed potential in identifying subjects at increased risk of exudative retinal changes. Subjects were assigned to groups in this study on the basis of fundus appearance. However, individuals within each subject group showed a range of retinal function which belied the homogeneity of retinal signs. This raises the question of whether 'form' or 'function' should form the basis of classification and assessment of individuals with ARM and AMD.
18
Al-Hosaini, Heba. "Age-related changes in retinal pigment epithelium". Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1444089/.
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The retinal pigment epithelium (RPE) is a monolayer of hexagonal organized cells located between the choriocapillaris and the neurosensory retina. As the RPE is implicated in a range of eye diseases, an understanding of its structure and ability for self renewal is critical for therapeutic strategies. Analysis of human RPE cells at the extreme periphery of the retina reveals a population larger in size than those in the centre, they are highly irregular and form an annulus of 4-5 mm. Although binucleation in humans is rare, 10% of these cells are binucleated. In the central region these large binucleated cells are only found adjacent to drusen, which are age-related lipid-rich deposits. Compared with humans, rat RPE is relatively homogeneous, however, the majority of its cells are binucleated, particularly in the central region. Human and rat RPE also shows different patterns of aging. In humans, the centre of the retina shows a significant reduction in RPE cell density with age, which was not observed in aged rats. The capacity of mature RPE cells to enter the cell cycle was investigated using a proliferative marker in rats. Here a subpopulation of mature peripheral RPE cells had the capacity to enter the cell cycle, and one-third of these cells completed cellular division. As RPE proliferation occur in response to retinal detachment, this was performed on rats and the patterns of gene expression in RPE examined. An increase was observed in nestin, PCNA and Ki67 expression, which was also confirmed at a protein level by immunohistochemistry. These results suggest that RPE cells have the capacity to proliferate and may possibly differentiate if subjected to appropriate stimuli in a normal retina.
19
Arena, Amanda. "Psychophysical correlates of age-related visual decline". Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/28385.
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Much of what we know about the physical world is afforded to us by vision. With age, our ability to perceive visual information can become compromised, affecting our autonomy and quality of life. Given the rapid aging of populations worldwide, it is imperative to develop a comprehensive understanding of the effects of age on visual function. Therefore, the aim of this thesis was to use psychophysical methods to examine the effects of 'healthy' aging on visual perception, with a particular emphasis on furthering our knowledge of age-related reductions in the perception of motion. In a series of experiments, observers ranging from 18-82 years of age were tested and compared on psychophysical tasks which measured orientation and direction sensitivity, first- and second-order global motion perception, contrast sensitivity, and visual attention as measured by the Useful Field of View. Four key findings are presented within this thesis: (1) older observers demonstrate reductions in orientation and direction sensitivity that can be attributed to increased internal noise in the aged motion pathway, (2) age related impairments in global motion perception are mediated by reductions in spatial integration, (3) older female populations may be particularly susceptible to age-related impairments in motion perception, and (4) there may be a selective impairment in the processing of second-order radial motion in the aged. The results of these experiments indicate that whilst some aspects of motion processing remain preserved with age, older observers demonstrate marked impairments on a number of motion tasks.
20
Strunk, Jonathan. "Age related changes in preparation of encoding". Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53385.
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A hallmark of aging is a decline in episodic memory. These memory impairments in older adults may be related to a shift away from proactive control strategies. Previous research, with young adults, suggests proactive processes can benefit memory encoding. The dual mechanisms of control model suggests changes in the recruitment of proactive and reactive control strategies will influence behavioral outcomes. The current study used EEG to investigated proactive control in episodic memory in aging. Both young and old adults completed a subsequent memory task with audio and visual items. Each item was preceded by a modality consistent cue. Participants also completed the AX-CPT, which is sensitive to the use of proactive strategies. We found both younger and older adults recruited proactive processes only for audio trials. Both groups exhibited proactive patterns of performance on the AX-CPT. Post-stimulus EEG suggests younger and older adults recruited different strategies for processing audio items. Visual items did not show subsequent memory effects in the pre-stimulus time period, but both groups showed post-stimulus effects. These results suggest younger and older adults are able to flexibly recruit proactive strategies that benefit memory performance.
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Gregory, D. J. "Age-related changes in inductive reasoning processes". Thesis, University of Aberdeen, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372614.
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Evans, Jennifer Rosemary. "Age-related macular degeneration in the UK". Thesis, London School of Hygiene and Tropical Medicine (University of London), 2003. http://researchonline.lshtm.ac.uk/682315/.
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The aim of this thesis was to investigate the prevalence and impact of age-related macular degeneration (AMD) causing visual impairment in people aged 75 years and above in the UK. A secondary objective was to investigate a small number of potential risk factors for AMD. This was an add-on study to the MRC Trial of the Assessment and Management of Older People in the Community. The prevalence of AMD causing visual impairment was estimated at 3.7% (95% confidence interval 3.2% to 4.2%) in people aged 75 years and above. This prevalence increased sharply with age. There was a higher risk of AMD causing visual impairment in women. There were estimated to be approximately 192,000 people aged 75 years and above in the UK living in the community with visual impairment due to AMD (95% confidence interval 144,000 to 239,000) of whom 60,000 are aged 90 years or above. The prevalence of AMD causing visual impairment did not vary by socio-economic group or region. After controlling for appropriate confounding factors, compared to people not visually impaired, people visually impaired due to AMD were more likely to have functional difficulties, report poor health and be depressed. They were more likely to be in the worst quintile for the home management and mobility dimensions of the Sickness Impact Profile (SIP). After controlling for appropriate confounding factors including binocular acuity score, compared to people visually impaired due to other causes, people visually impaired due to AMD were more likely to have functional difficulties and report poor health and less likely to be in the worst quintile for SIP body care and movement dimension or die. There was an association between smoking status and risk of being visually impaired due to AMD. This effect was particularly strong in people aged 75-79 years of age. In these people there was a dose-response relationship between pack years of smoking and risk of AMD causing visual impairment. There were no statistically significant associations between alcohol consumption, cardiovascular disease and reproductive factors (in women) and AMD causing visual impairment.
23
Goverdhan, Srinivas. "Immunogenetic pathways in age related macular degeneration". Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/66006/.
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Renganathan, Kutralanathan. "Oxidative Damage and Age Related Macular Degeneration". Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1193002743.
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Wang, Yang. "Gene Discovery for Age-related Macular Degeneration". Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1228364622.
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NI, JIAQIAN. "Plasma Biomarkers for Age-Related Macular Degeneration". Cleveland State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1236700270.
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Cluny, Vasco Silva Oliveira. "Exploratory study of age related epigenomic patterns". Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17887.
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Mestrado em Biotecnologia MolecularSabe-se hoje que o genoma humano, para além da sua sequencia nucleotídica, revela várias alterações químicas no DNA, nomeadamente metilações das citosinas. Estas modificações estabelecem padrões específicos que podem ser transmitidos de uma geração para a seguinte e exercem controlo sobre os genes que são expressos a cada momento nas células, tecidos ou orgãos. Esta tese teve como objectivos: explorar as principais bases de dados que contêm dados epigenómicos relevantes; obter ficheiros fastq de bibliotecas bisulfite-seq aplicando métodos de data mining a dados reais de bases de dados públicas de sequenciação de segunda geração; alinhar e mapear estes ficheiros usando software adequado (Methy-Pipe); fazer uma análise comparative por forma obter características associadas ao envelhecimento saudável de indivíduos e á evolução do epigenoma ao longo da vida; finalmente é esperado que, após atingidos os objectivos anteriores, se perceba o contributo do epienoma no envelhecimento saudável das populações .
It is already known today, that the human genome, in addition to its nucleotide sequence, shows multiple chemical modifications at the DNA level, namely cytosine methylations. These modifications changes establish specific patterns that can be transmitted from generation to generation and exercise control over the genes that are expressed at every moment in the life of the cells / tissues / organs. This thesis aimed to: understand the contribution of the epigenome to a healthy lifestyle; to explore the main databases containing relevant epigenomic data; to obtain fastq files of bisulfite-seq libraries by applying data mining methods to real data from next generation public databases; to align and map these files using adequate software (Methy Pipe); to do a comparative analysis in order to identify features associable to a healthy aging of individuals and the evolution of the epigenome in humans throughout life.In doing so, it is expected that this work will contribute to the understanding of the contribution of the epigenome to a healthy lifestyle.
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Wu, Juan. "Dietary Determinants of Age-Related Macular Degeneration". Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:27201715.
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Age-related macular degeneration (AMD) is the most common cause of irreversible blindness in older Americans. There has been a long standing interest in the role of diet in the development of AMD. As early as the first National Health and Nutrition Examination Survey in the 1970s, higher intakes of fruits and vegetables were inversely correlated with the prevalence of AMD. Carotenoids and omega3 fatty acids are the most studied dietary factors due to strong biological plausibility. However, evidence from epidemiologic studies and clinical trials on the relations has been inconsistent.
Chapter I prospectively examined the intakes of lutein/zeaxanthin and other common carotenoids in relation to the risk of AMD over more than two decades of follow-up among two large US cohorts, the Nurses’ Health Study and Health Professionals Follow-Up Study. We assessed nutrient intakes by repeated food frequency questionnaires. We also computed bioavailable plasma carotenoid scores directly from food intake using validated regression models. Cox proportional hazards models were used to compute the associations. Higher intakes of bioavailable carotenoids (except lycopene) were inversely associated with advanced AMD but not intermediate AMD. Analyses based on bioavailable intakes resulted in stronger associations than conventional nutrient intakes.
Chapter II prospectively evaluated the marine long-chain omega3 fatty acids. We found that long-chain omega3 fatty acids were inversely associated with visually significant intermediate AMD. There was no association with advanced AMD; however, the totality of current evidence for advanced AMD is also discordant.
Chapter III further investigated the plant-derived omega3 fatty acids, α-linolenic acid (ALA). We found that higher intake of ALA was associated with intermediate AMD before 2002 but not after. This coincides with the same time period when trans ALA was found in our participants’ blood and in mayonnaise, a primary food source of ALA. Whether trans ALA mediates this positive association warrants further studies.
Although randomized trials are usually believed as the “gold standard”, dietary factors are hard to be adequately studied by randomized trials due to the complexities of diet and disease relations. Thus, findings in this thesis from large long-term prospective cohort studies provide the next best form of evidence.
29
Wang, Yang. "Gene discovery of age-related macular degeneration". Cleveland, Ohio : Case Western Reserve University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1228364622.
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Rosenzweig, Ephron. "Age-related changes in hippocampal map realignment". Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/289784.
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The activity of hippocampal pyramidal cells (place cells) is correlated with the position of a rat in a given environment, suggesting that the rat hippocampus may contain a cognitive map of the environment. Internally-generated information about the motion of the rat may be the strongest initial determinant of place-cell firing. With experience in a given environment, cues and landmarks may gain control over place-cell firing, allowing the correction of errors or drift in the self-motion information. This 'binding' of cues to the hippocampal map may involve long-term potentiation (LTP). Because hippocampal LTP is impaired in aged rats, cues and landmarks should be poorly bound to the hippocampal map in aged rats. To test this prediction, aged and adult rats were trained to run back and forth on a linear track. The position of the start box was changed from trial to trial, so that self-motion information (i.e., the distance of the rat from the start box) and visual-cue information (the position of the rat in the room) were mismatched. In this situation, self-motion information controls place-cell firing during the initial portion of each journey. At some point in each journey, however, the hippocampal map realigns, so that place-cell firing is controlled by visual-cue information. If age-related LTP deficits impair the binding of cues to the hippocampal map, this realignment should be delayed in aged rats. As predicted, the realignment occurred nearer to the end of the track in the aged rats. Moreover, the delayed realignment was correlated with the rats' ability to find a hidden goal at a position relative to the visual cues. The results suggest that some of the spatial-learning deficits observed in aged rats may be due to impaired binding of cues to the hippocampal map. In addition, despite the fact that the animals in the present study had never been trained with a stable start box (the anchor point for self-motion information), place-cell firing was controlled by self-motion information for a large portion of each outbound journey. This result supports a strong initial role of self-motion information in determining the hippocampal representation of a rat's position.
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Hemphill, Mandy. "Vitamin D and Age-Related Macular Degeneration". ScholarWorks, 2017. https://scholarworks.waldenu.edu/dissertations/3448.
Pełny tekst źródłaStreszczenie:
Age-related macular degeneration (AMD) is the leading cause of vision loss in individuals aged 50 years and older and is estimated to affect as many as 11 million individuals in the United States. The purpose of this study was to examine the association between vitamin D and AMD disease progression. The life course epidemiology framework model was used to explore how vitamin D level as a risk factor may have an association to AMD disease through time. Data in the 2005-2008 National Health and Nutrition Examination Survey (NHANES) database were collected on vitamin D levels and identified stages of AMD level based on graded fundus eye exams from an available sample size of 5,604 participants. A quantitative cross-sectional study approach was used to address this gap in knowledge. A bivariate analysis was used to examine each independent variable (age, race/ethnicity, smoking status, and diabetes) to the dependent variable AMD from the 2005-2008 NHANES dataset. A multivariate logistic regression analysis was performed with AMD including each independent variable found to be significant. The findings from this study failed to suggest an association between vitamin D levels to AMD, with or without the covariates included in the model. There was not an association found between vitamin D level and presence of AMD. An association was found between age, smoking, and race to presence of AMD in each of the bivariate models. The findings from this study could be used for positive social change by encouraging medical and public health agencies to target screening programs at high-risk age, smoking, and race groups. There remains to be conflicting data in the literature. This study adds to the body of literature suggesting that higher levels of vitamin D are not necessarily beneficial as they pertains to AMD.
32
Whitmore, Steven Scott. "Molecular investigations of age-related macular degeneration". Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/1798.
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An estimated 170.38 million elderly adults suffer from some stage of age-related macular degeneration (AMD) worldwide, a vision defect that damages the macula, the central region of the retina required for sharp vision, such as reading, driving, and recognizing faces. Genetic factors strongly modify one's risk for developing AMD, and most of these genetic changes are found in genes of the alternative complement cascade, a component of the immune system. The lack of effective AMD prevention calls for the identification of druggable molecules and pathways.
In my research, I use microarrays and RNA sequencing to investigate the events occurring in early AMD, the reasons for macular susceptibility to AMD, and the events triggering aberrant blood vessel growth in late AMD. First, I found that genes associated with endothelial cells tend to be expressed at lower levels in human donors eyes affected by early AMD than in control eyes, concordant with previous studies indicating loss of choriocapillaris in early AMD. Second, I found that molecular signals across regions of the retina, retinal pigment epithelium, and choroid generally mirror the distribution of cell types in these regions. Third, I found that damage to cultured primate chorioretinal endothelial cells by the end product of complement activation, membrane attack complex, produces an environment conducive to choroidal neovascularization, a symptom of late-stage AMD. I propose a model that bridges genetic variants in the complement cascade genes with blood vessel loss in early AMD and the pathological growth of blood vessels in late AMD.
33
Swann, Peter G. "The visual field in age related maculopathy". Thesis, Queensland University of Technology, 1988. https://eprints.qut.edu.au/36726/1/36726_Swann_1988.pdf.
Pełny tekst źródłaStreszczenie:
Age-related maculopathy (ARM) is a leading cause of permanent vision
loss in elderly people. ARM therefore constitutes an important public
health problem which will increase in magnitude as the number of aged
people in the general population becomes greater. The consequences of
this condition are exacerbated by the fact that treatment, especially
of the geographic or dry form of the disease, is ineffective. While
laser photocoagulation may be helpful in the exudative, disciform or
wet form of ARM, there is often an inexorable progression towards
severe vision loss in these patients. Therefore considerable
attention needs to be paid to the aetiology of ARM with the potential
for its prevention or delayed onset, and its recognition th rough
functional disturbances.
This study addressed the character of visual field 1 oss in ARM and
compared the efficacy of the Friedmann Visual Field Analyser, Mark II
(FVFA), the Autoplot Tangent Screen and Amsler charts in the detection
of this loss. Data for a group of subjects with ARM were compared
with those for a group of subjects with pre-age related macul opathy
(PARM), (that is, ophthalmoscopically visible changes at the macula in
the presence of normal vision (6/6)), and also with groups of elderly
and young normal subjects.
The study has shown that the visual field defects in ARM are
predominantly paracentral with a relative sparing of foveal
sensitivity. PARM subjects did not show a significant visual field
disturbance with the FVFA or Auto plot, however, three PARM subjects
did have slight distortions with the standard Amsler chart test. Of
the methods used in this study, the Amsler charts may be the preferred
method of examination of PARM subjects. Alternatively, an examination
with a static, computerised perimeter using coloured stimuli may be
used.
In the presence of visual field loss in ARM subjects, the FVFA
compared well with the Autoplot tangent screen, and highly significant
carrel ati ons were found between FVFA neutral density filter settings and equivalent Auto plot target sizes. Similarly, the Amsler charts
are a very useful method of investigation of the central visual field
and a threshold method of presentation of the test may prove helpful.
In the future, most attention should be directed towards detecting
early functional disturbances in PARM subjects. Previous research and
this study have shown that an investigation of these subjects with
high and low contrast visual acuity charts, Amsler charts, the
Desaturated D-15 test, and glare recovery tests prove more effective
than examination with the FVFA or Auto plot tangent screen. The
usefulness of examining these subjects with a computerised perimeter
using appropriate stimuli and testing strategies should be thoroughly
investigated.
34
Davis, Craig A. "Psychosocial adjustment to age-related vision loss". Thesis, Queensland University of Technology, 1992. https://eprints.qut.edu.au/36809/1/T%28HS%29%2086_Digitised%20Thesis.pdf.
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Both the number and proportion of the elderly and people with chronic disability are increasing as a proportion of the entire population, particularly in the over 80 years age range. The most common cause of chronic visual disability in the elderly is age-related maculopathy (ARM). Chronic visual disability, manifested as functional limitations of activities of daily living, often results in psychosocial handicap due to ineffective coping skills. Both low vision services and low vision research have previously been oriented toward functional adjustment to disability, rather than psychosocial aspects of vision loss. Previous disability research has sought to explain psychosocial adjustment in terms of mediators of stress, such as involved in "stress and coping" theory. Recent research interest in measures of rehabilitation outcome have used psychosocial factors as key indicators of adjustment. This study investigates both mediators and measures of psychosocial adjustment to chronic vision loss using a modified stress and coping model.
The study consisted of two groups: thirty elderly people with vision loss due to age-related maculopathy (ARM), and thirty elderly people (controls), age-matched and sex-matched to the ARM group but with normal vision. Data were collected, in an interview format in subjects' homes, on four psychosocial scales (life satisfaction, daily hassles, social support, and self-esteem) and a measure of self-care. In addition, information on history of visual impairment, use of optical devices, use of rehabilitation resources, distance and near visual acuity, and demographic factors were also collected.
In terms of the model presented, psychosocial results confirmed several, but not all relationships defined within the model and it appears to serve as a useful framework with which to understand the mediating factors in psychosocial adjustment to age-related vision loss. The results tend to suggest that people with chronic age-related vision loss report poorer psychosocial adjustment (as indicated by significantly poorer life satisfaction and greater stress) than age- and sex-matched controls, perhaps as a result of poorer perceptions of social support, despite rehabilitative attention.
Several results have implications for the functional rehabilitation of ARM. ARM subjects were found to have significantly poorer mobility and fewer daily activities than control subjects. Reading, recognised as important for both survival and recreational activities for many people with ARM, requires regular follow-up, as indicated by results showing gradual deterioration in vision in the ARM group being associated with poor satisfaction with prescribed reading devices, despite the majority of subjects still using the device daily. People with ARM would therefore seem to prefer to persevere with a coping strategy that is unsatisfactory in order to retain some independence in functioning.
Despite several of the individual psychosocial measures used demonstrating their usefulness as measures of psychosocial adjustment, the validity of each of the measures used is questioned. Although the methodology herein does not allow interpretation as to predictors of psychosocial adjustment following onset of vision loss (or indeed following rehabilitation services), interpretation can be made regarding factors important in the adjustment process and inter-relationships between factors. From a clinical perspective therefore, results indicate that effective low vision rehabilitation should include programs that incorporate both psychosocial adjustment and functional adjustment services. Future research is recommended to develop new measures of psychosocial adjustment to age-related vision loss.
35
Cameli, Luisa. "Age-related differences in semantic priming : evidence from event-related brain potentials". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0005/MQ43618.pdf.
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Knoefel, Mark-Ulrich. "Age-related morphological changes in fifth cervical vertebrae". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0018/MQ47050.pdf.
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Svoboda, Eva-Maria. "Autobiographical interview, age-related differences in episodic retrieval". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58879.pdf.
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Lindahl, Lisbeth B. "Gender and age related developmental processes during infancy". Göteborg, 1998. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=008620427&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Corder, Erin E. "Age-related changes in oro-facial motor performance". Thesis, Wichita State University, 2012. http://hdl.handle.net/10057/5525.
Pełny tekst źródłaStreszczenie:
Older adults speak 20-30% slower than younger adults. A decline in articulatory speed capacity has often been suggested; however, direct investigations on speech motor performance have rarely been conducted. Therefore, this study sought to determine if jaw speed capacity is reduced in older adults. This study included 36 female participants in four age groups: young adult, middle-aged, young-old, and very old. Each participant completed a jaw oscillation task at seven metronome paces. Similar to previous studies on upper limb speed capacity, participants were asked to tap a fixed target with their jaw at each metronome beat. The metronome pace determined the jaw movement duration and the target determined the jaw movement excursions during the experimental conditions. Jaw peak speeds, excursion, and movement durations during the jaw closing strokes were compared between the four age groups. Study outcomes showed that jaw speed capacity was significantly lower in the youngest age group relative to all other age groups. Jaw speed capacity did not significantly differ between middle-aged, young-old, and very old adults. These findings contrasted previous reports of aging studies on limb speed capacity. Further, these findings on jaw speed capacity suggested that jaw peak speed may not be a factor that contributes to a slowed speaking rate in older adults. In the future, jaw speed capacity of male speakers needs to be investigated. Further, aging-related changes in tongue and lip speed capacities also should be determined to gain more comprehensive insights in physiologic factors that may affect speaking rates of older adults.Thesis (M.A.)--Wichita State University, College of Health Professions, Dept. of Communication Sciences and Disorders
40
Moffatt, Karyn Anne. "Addressing age-related pen-based target acquisition difficulties". Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/19189.
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Technology is increasingly being promoted as a means of addressing age-related cognitive and sensory impairments and enabling seniors to live more independently. Pen-based devices such as Personal Digital Assistants and Tablet PCs are
appealing platforms for these endeavors because they are small, mobile, and powerful. Relative to the mouse, pen-based devices have been shown to be particularly beneficial for older adults. However, in terms of garnering wide-spread adoption, the mouse has historically dominated, leading researchers to focus chiefly on identifying and addressing its age- and motor-related limitations. In contrast, pen-based limitations for older users have been relatively unexplored. This thesis begins to fill that gap in the literature.
Our first experiment, an empirical evaluation of pen-based target acquisition across the adult lifespan, identified three main sources of pen-based target acquisition difficulty—missing-just-below, slipping, and drifting—and demonstrated how these difficulties vary across task situation and age. In addition, this work showed that including older adults as participants can help uncover general pen-interaction problems: the missing-just-below and drifting difficulties were evident in both younger and older users alike.
We next developed seven new target acquisition techniques to improve pen-based interaction, specifically addressing the three difficulties identified, and particularly targeting older adults. Our techniques built upon existing mouse-based techniques developed for older users and pen techniques for younger users. In
total, we conducted three experiments to evaluate the seven new pen-based techniques: Reassigned and Deactivated (for missing-just-below), Tap and Glide (for drifting), and Steady, Bubble, and Steadied-Bubble (for slipping). Through these evaluations, we established where our proposed designs were successful at reducing errors, and where further refinement is needed.
Finally, we reflected on our findings across studies to identify age-related, contextual, and technological factors which contributed to our results. These factors help illuminate the underlying reasons for pen-based targeting difficulties and shed light onto areas still needing attention. Overall, the results of this research support our main thesis that the accessibility of pen-based interfaces can be improved for older adults by first examining the sources of age-related acquisition difficulty, and
then using the results of this examination to develop improved techniques.
41
Pollard, Andrews John. "Age-related changes in immunity to Neisseria meningitidis". Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314059.
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Gaffney, Allannah J. "Characterising adaptational dysfunction in age-related macular degeneration". Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/41072/.
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Age-related macular degeneration (AMD) is the leading cause of visual impairment in the developed world. The prevalence of this disease will continue to increase over the coming decades as the average age of the global population rises. There is consequently an urgent need to develop tests that are sensitive to early visual dysfunction, in order to identify individuals that have a high risk of developing AMD, to identify patients that would benefit from treatment, to assess the outcomes of that treatment and to evaluate emerging treatment strategies. An emerging body of evidence suggests that dark adaptation is a sensitive biomarker for early AMD. Cone dark adaptation is of particular interest to clinicians, as it can identify patients with early AMD in a relatively short recording period. Consequently, this thesis aimed to optimise psychophysical and electrophysiological techniques for the assessment of cone dark adaptation in early AMD, in order to maximise its diagnostic potential. A range of psychophysical methods were shown to be capable of monitoring the rapid changes in threshold that occur during cone dark adaptation. An optimal psychophysical protocol for the assessment of cone dark adaptation in early AMD was developed based on the results of a systematic evaluation of the effect of stimulus parameters and pre-adapting light intensity on the diagnostic potential of cone dark adaptation in early AMD. When compared to the focal cone ERG photostress test, both techniques were shown to be similarly diagnostic for early AMD. In addition, the time constant of cone recovery was shown to be significantly correlated with age, hence the sensitivity and specificity of cone dark adaptation as a biomarker for early macular disease may be further improved by considering these age-related changes. In conclusion, this thesis has confirmed that cone dark adaptation is a sensitive functional biomarker for early AMD. However, as cross-sectional studies are unable to determine the true diagnostic potential of a biomarker, longitudinal investigations are needed to explore the long-term potential of cone dark adaptation and other visual functions as biomarkers for early AMD.
43
Wood, Ashley. "Retinal structure and function in age-related maculopathy". Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/22429/.
Pełny tekst źródłaStreszczenie:
Age-related macular degeneration (AMD) is the principle cause of visual loss and blindness in the developed world. As new treatments and therapies are developed the need to better diagnose and then monitor outcomes of treatment has become more important. This thesis evaluates both structural and functional changes that occur in the early stage of AMD, known as age-related maculopathy (ARM), with the aim of determining their diagnostic potential. This thesis also explores the relationship between structural and functional parameters. Twenty four participants with ARM and 26 control participants were recruited. Retinal function was probed using four focal electroretinography (ERG) techniques: the focal cone ERG, focal flicker ERG, ERG photostress test and focal rod ERG. Long wavelength optical coherence tomography (OCT) was used to assess retinal structure, specifically retinal, choroidal and four intra-retinal layer thicknesses at 21 macular locations. These techniques were initially developed and optimised for the detection of AMD related changes. The ability of each parameter to diagnose ARM was assessed. Correlation and linear regression analyses were carried out to identify any relationships between retinal structure and function in healthy controls. Retinal thickness was reduced in participants with ARM at parafoveal locations (~2° eccentricity), but choroid thickness was unaffected. Diagnostically, focal ERG parameters provided better sensitivity and specificity to ARM than OCT measures, with the ERG photostress test providing the best diagnostic potential. No strong relationships were shown between any ERG parameter and any retinal or choroidal layer volume in control participants. Three ERG parameters were shown to be related to specific retinal features of ARM, but the strongest associations were between ERG photostress test recovery and focal cone ERG b-wave implicit time and a diagnosis of wet AMD in the contralateral eye. In conclusion the structural and functional parameters assessed appeared to provide independent information regarding disease status and severity. ERG parameters showed better diagnostic potential than OCT measures. The single most diagnostic parameter was the recovery time constant of the ERG photostress test.
44
Schiavone, Francesca. "Age related white matter changes and neuropsychological correlates". Thesis, St George's, University of London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511960.
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Szewczuk, Elizabeth. "Age-Related Infertility : A Tale of Two Technologies". Thesis, University of Essex, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517395.
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Blount, Daniel Graham. "Age-related immunological changes in labrador retriever dogs". Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436864.
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Robertson, Dorothy R. C. "Age-related changes in drug absorption and metabolism". Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295900.
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Imraish, Amer. "Age-related changes in the phenotype of microglia". Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/52934/.
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Microglia play a central role in immune surveillance and modulation of neuroinflammation as well as playing a role in neurodevelopment. Microglia involve in the development of pathological pain in adults but not early in life. However little detail is known about the changing phenotype of microglia during development. We examined age-related changes in microglia following activation with pathogen- and damage- associated molecular patterns (PAMPs/DAMPs). Microglial cultures were prepared from neonatal postnatal day (P1) and adult (P40) rat brains and spinal cords. Immunocytochemistry, qRT-PCR and functional assays were used to identify age-related differences. Adult microglia display a pro-inflammatory immune profile characterized by significantly increased IL-1β mRNA levels in response to PAMPs and DAMPs. In contrast, IL-1β mRNA in neonatal microglia showed a slight increase after stimulation with DAMPs. Anti-inflammatory gene expression was significantly increased in neonatal microglia relative to adult microglia. Compared to adult microglia, neonatal cells had increased phagocytic activity when unstimulated and following activation with LPS and ATP. Moreover, the nuclear receptor Nurr1 may play a major role in reducing pro-inflammatory signalling and promoting the anti-inflammatory phenotype in neonatal microglia. Nurr1 isoforms are differentially expressed in neonatal and adult microglia, with the Nurr1a isoform being significantly elevated in neonatal cells. Using lentiviral vector-mediated expression of Nurr1 isoforms, we also show that over-expression of TINUR, a splice variant of Nurr1, in neonatal and adult microglia attenuates inflammation by trans-repression the IL-1β expression and trans-activation the IL-10 gene expression following ATP exposure. Together, these data provide evidence for age-related difference in microglial function during postnatal development. In addition, these findings demonstrate insight into the mechanisms by which Nurr1 might act, and suggest potential therapeutic targets for the treatment of neuro-inflammatory diseases.
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Pushpoth, Sreekumari. "Use of metabolomics in age-related macular degeneration". Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8371/.
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Age-related macular degeneration (AMD) is a major cause of irreversible central sight loss in the elderly. Many factors affect disease onset and progression, and these include age, environmental stressors such as smoking, diet, inflammation and genetic polymorphisms, all of which are likely to influence metabolism. In some complex diseases, metabolomics, which involves the identification of a metabolic fingerprint in a biofluid or tissue, has been shown to discriminate metabolic changes associated with different disease processes and to identify specific phenotypes. We have applied metabolomics, in the first study of its kind, to analyse, using NMR spectroscopy, both serum and urine metabolic characteristics in patients with dry and wet AMD (n=104). NMR spectral analysis showed good clustering as well as separation among the serum and urine from dry and wet AMD patients. The results show that metabolite profiles can distinguish dry and wet AMD, but that the pathways involved, glycolysis, urea cycle and Kreb’s cycle, are involved in both forms of the disease. It is likely that the pathogenesis of dry and wet AMD is similar and that the severity of ocular damage and systemic inflammation would account for the distinguishing profiles. These data support the use of metabolomics in identifying biological pathways involved in pathogenesis of AMD, but not in the diagnosis or prognosis of disease.
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Dandekar, Samantha Sujata. "Detailed clinical phenotyping in Age-related Macular Degeneration". Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1444668/.
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Age-related Macular Degeneration (AMD) is a degenerative disorder that accounts for about 50% of blindness in England and Wales. At present there is no effective treatment. It occurs in genetically susceptible individuals exposed to environmental factors such as smoking but so far specific factors remain to be identified. For this descriptive study, 879 patients with Age-Related Maculopathy (ARM) and AMD and 44 spouses with normal maculae, to act as a comparison group, were recruited from a tertiary referral centre. The clinical phenotypes were analysed from fundus photographs, fluorescein angiography and autofluorescence (AF) images. Fundus features were characterised as they are thought to reflect the genes conferring risk in an individual and may allow greater understanding of disease mechanisms. These data demonstrated (1) A revised grading system shown to be reproducible for use with digital images (2) A moderate concordance rate for phenotype between eyes with end- stage AMD (kappa statistic=0.48 95% CI = 0.38-0.57, p0.001). (3) Distinct characteristics, including a larger area and higher counts of soft drusen with focal areas of increased AF, in fellow eyes of those with unilateral visual loss due to geographic atrophy (GA). (4) An increased susceptibility of the inferotemporal macula to GA. (5) Preserved integrity of the retinal pigment epithelium (RPE) in the initial stages of CNV development as identified from AF images. (6) Loss of scotopic rather than photopic function over areas of increased AF, as determined by fine matrix mapping, indicating the preferential vulnerability of rods. (7) No difference in smoking history between those with neovascular compared to non-neovascular AMD. Although AMD has been extensively investigated, this study extends our knowledge of retinal AF, the relative susceptibility of rods compared to cones at the macula and suggests both eyes of an individual are more discordant for late stages of AMD compared to drusen.