| 1. |
- Riņķevič, Kaspars, et al.
(författare)
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Equality in cumulative voting : A systematic review with an improvement proposal
- 2013
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Ingår i: Information and Software Technology. - : Elsevier. - 0950-5849 .- 1873-6025. ; 55:2, s. 267-287
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Tidskriftsartikel (refereegranskat)abstract
- Context: Prioritization is an essential part of requirements engineering, software release planning and many other software engineering disciplines. Cumulative Voting (CV) is known as a relatively simple method for prioritizing requirements on a ratio scale. Historically, CV has been applied in decision-making in government elections, corporate governance, and forestry. However, CV prioritization results are of a special type of data-compositional data. Objectives: The purpose of this study is to aid decision-making by collecting knowledge on the empirical use of CV and develop a method for detecting prioritization items with equal priority. Methods: We present a systematic literature review of CV and CV analysis methods. The review is based on searching electronic databases and snowball sampling of the found primary studies. Relevant studies are selected based on titles, abstracts, and full text inspection. Additionally, we propose Equality of Cumulative Votes (ECVs)-a CV result analysis method that identifies prioritization items with equal priority. Results: CV has been used in not only requirements prioritization and release planning but also in e.g. software process improvement, change impact analysis and model driven software development. The review presents a collection of state of the practice studies and CV result analysis methods. In the end, ECV was applied to 27 prioritization cases from 14 studies and identified nine groups of equal items in three studies. Conclusions: We believe that the analysis of the collected studies and the CV result analysis methods can help in the adoption of CV prioritization method. The evaluation of ECV indicates that it is able to detect prioritization items with equal priority and thus provide the practitioner with a more fine-grained analysis.
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| 2. |
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| 3. |
- Alafuzoff, Irina, et al.
(författare)
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The need to unify neuropathological assessments of vascular alterations in the ageing brain : Multicentre survey by the BrainNet Europe consortium
- 2012
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Ingår i: Experimental Gerontology. - : Elsevier BV. - 0531-5565 .- 1873-6815. ; 47:11, s. 825-833
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Tidskriftsartikel (refereegranskat)abstract
- Here, we summarise the results after carrying out a large survey regarding the assessment of vascular alterations, both vessel changes and vascular lesions in an inter-laboratory setting. In total, 32 neuropathologists from 22 centres, most being members of BrainNet Europe (BNE), participated by filling out a questionnaire with emphasis on assessment of common vascular alterations seen in the brains of aged subjects. A certain level of harmonisation has been reached among BNE members regarding sectioning of the brain, harvesting of brain tissue for histology and staining used when compared to the survey carried out in 2006 by Pantoni and colleagues. The most significant variability was seen regarding the assessment of severity and of clinical significance of vascular alterations. Two strategies have recently been recommended regarding the assessment of vascular alterations in aged and demented subjects. The National Institute on Aging - Alzheimer's Association (NIA-AA) recommends the assessment of hippocampal sclerosis, vascular brain injury and microvascular lesions in 12 regions. Although this strategy will be easy to follow, the recommendations do not inform how the load of observed alterations should be assessed and when the observed lesions are of significance. Deramecourt and his colleagues recommend an assessment and semiquantitative grading of various pathologies in 4 brain regions. This strategy yielded a total score of 0 to 20 as an estimate of pathology load. It is, however, not clear which score is considered to be of clinical significance. Furthermore, in several BNE trials the semiquantitative assessment has yielded poor agreement rates; an observation that might negatively influence the strategy proposed by Deramecourt and his colleagues. In line with NIA-AA, a dichotomised approach of easily recognisable lesions in a standardised set of brain regions harvested for neuropathological assessment and applying reproducible sampling and staining strategies is recommended by BNE. However, a simple strategy regarding assessment of load of alteration is urgently needed to yield reproducible, and at the same time, comparable results between centres.
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| 4. |
- Alderman, J. McKee, et al.
(författare)
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Neuroendocrine inhibition of glucose production and resistance to cancer in dwarf mice
- 2009
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Ingår i: Experimental Gerontology. - : Elsevier BV. - 0531-5565 .- 1873-6815. ; 44:1-2, s. 26-33
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Tidskriftsartikel (refereegranskat)abstract
- Pit1 null (Snell dwarf) and Proph1 null (Ames dwarf) mutant mice lack GH, PRL and TSH. Snell and Ames dwarf mice also exhibit reduced IGF-I, resistance to cancer and a longer lifespan than control mice. Endogenous glucose production during fasting is reduced in Snell dwarf mice compared to fasting control mice. In view of cancer cell dependence on glucose for energy, low endogenous glucose production may provide Snell dwarf mice with resistance to cancer. We investigated whether endogenous glucose production is lower in Snell dwarf mice during feeding. Inhibition of endogenous glucose production by glucose injection was enhanced in 12 to 14 month-old female Snell dwarf mice. Thus, we hypothesize that lower endogenous glucose production during feeding and fasting reduces cancer cell glucose utilization providing Snell dwarf mice with resistance to cancer. The elevation of circulating adiponectin, a hormone produced by adipose tissue, may contribute to the suppression of endogenous glucose production in 12 to 14 month-old Snell dwarf mice. We compared the incidence of cancer at time of death between old Snell dwarf and control mice. Only 18% of old Snell dwarf mice had malignant lesions at the time of death compared to 82% of control mice. The median ages at death for old Snell dwarf and control mice were 33 and 26 months, respectively. By contrast, previous studies showed a high incidence of cancer in old Ames dwarf mice at the time of death. Hence, resistance to cancer in old Snell dwarf mice may be mediated by neuroendocrine factors that reduce glucose utilization besides elevated adiponectin, reduced IGF-I and a lack of GH, PRL and TSH, seen in both Snell and Ames dwarf mice. Proteomics analysis of pituitary secretions from Snell dwarf mice confirmed the absence of GH and PRL, the secretion of ACTH and elevated secretion of Chromogranin B and Secretogranin II. Radioimmune assays confirmed that circulating Chromogranin B and Secretogranin II were elevated in 12 to 14 month-old Snell dwarf mice. In summary, our results in Snell dwarf mice suggest that the pituitary gland and adipose tissue are part of a neuroendocrine loop that lowers the risk of cancer during aging by reducing the availability of glucose.
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| 5. |
- Benedict, Christian, et al.
(författare)
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Intranasal insulin as a therapeutic option in the treatment of cognitive impairments
- 2011
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Ingår i: Experimental Gerontology. - : Elsevier BV. - 0531-5565 .- 1873-6815. ; 46:2-3, s. 112-115
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Tidskriftsartikel (refereegranskat)abstract
- The brain is a major target of circulating insulin. Enhancing central nervous insulin action has been shown to improve memory functions in animals as well as in humans, benefitting in particular hippocampus-dependent (declarative) memory. As Alzheimer's disease (AD) is associated with reduced central nervous insulin signaling and attenuated permeation of blood-borne insulin across the blood-brain-barrier, the cognitive decline in AD patients may at least in part be derived from impaired brain insulin signaling. Thus, therapeutic strategies to overcome central nervous system insulin deficiency and resistance might be an attractive option in the treatment of cognitive impairments like AD. Insulin can be effectively delivered directly to the brain via the intranasal route that enables the hormone to bypass the blood-brain barrier and modulate central nervous functions. This review summarizes a series of studies demonstrating beneficial effects of intranasal insulin on memory functions both in healthy humans and in patients with cognitive impairments such as AD. These experiments in humans consistently indicate that enhancing brain insulin signaling by intranasal administration of the hormone improves hippocampus-dependent memory in the absence of adverse side effects. Considering that insulin also acts as a neuroprotective signal, up-regulating brain insulin levels by intranasal insulin administration appears to be a promising approach in the treatment and prevention of central nervous system insulin deficiency and resistance as found in AD.
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| 6. |
- Boussard, Annika, et al.
(författare)
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The link between relative brain size and cognitive ageing in female guppies (Poecilia reticulata) artificially selected for variation in brain size
- 2021
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Ingår i: Experimental Gerontology. - : Elsevier BV. - 0531-5565 .- 1873-6815. ; 146
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Tidskriftsartikel (refereegranskat)abstract
- Cognitive ageing is the general process when certain mental skills gradually deteriorate with age. Across species, there is a pattern of a slower brain structure degradation rate in large-brained species. Hence, having a larger brain might buffer the impact of cognitive ageing and positively affect survival at older age. However, few studies have investigated the link between relative brain size and cognitive ageing at the intraspecific level. In particular, experimental data on how brain size affects brain function also into higher age is largely missing. We used 288 female guppies (Poecilia reticulata), artificially selected for large and small relative brain size, to investigate variation in colour discrimination and behavioural flexibility, at 4-6, 12 and 24 months of age. These ages are particularly interesting since they cover the life span from sexual maturation until maximal life length under natural conditions. We found no evidence for a slower cognitive ageing rate in large-brained females in neither initial colour discrimination nor reversal learning. Behavioural flexibility was predicted by large relative brain size in the youngest group, but the effect of brain size disappeared with increasing age. This result suggests that cognitive ageing rate is faster in large-brained female guppies, potentially due to the faster ageing and shorter lifespan in the large-brained selection lines. It also means that cognition levels align across different brain sizes with older age. We conclude that there are cognitive consequences of ageing that vary with relative brain size in advanced learning abilities, whereas fundamental aspects of learning can be maintained throughout the ecologically relevant life span.
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| 7. |
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| 8. |
- Bruno, Davide, et al.
(författare)
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Levels of cerebrospinal fluid neurofilament light protein in healthy elderly vary as a function of TOMM40 variants.
- 2012
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Ingår i: Experimental gerontology. - : Elsevier BV. - 1873-6815 .- 0531-5565. ; 47:5, s. 347-52
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Tidskriftsartikel (refereegranskat)abstract
- Neurofilament light (NFL) proteins in cerebrospinal fluid (CSF) are a marker of neuronal damage, especially subcortical axonal injury and white matter disease. Subjects with Alzheimer's disease (AD) have shown elevated levels of CSF NFL as compared to controls. However, the presence of the APOE ε4 allele, an established risk factor for AD, was not found to associate with higher CSF NFL concentrations. We examined whether TOMM40 variants, which have been reported to influence age of onset of AD and are in linkage disequilibrium with APOE, have an effect on CSF NFL levels, in 47 healthy, cognitively intact individuals with or without APOE ε4. Our results show that the presence of APOE ε4 alone does not affect CSF NFL levels significantly; however APOE and TOMM40 appear to interact. Subjects with APOE ε4 have higher CSF NFL levels than non-ε4 carriers, only when they do not carry a short poly-T variant of TOMM40, which is associated with later age of onset of AD, and may act as protective against the dose effect of ε4.
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| 9. |
- Buerger, Katharina, et al.
(författare)
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Validation of Alzheimer's disease CSF and plasma biological markers: the multicentre reliability study of the pilot European Alzheimer's Disease Neuroimaging Initiative (E-ADNI).
- 2009
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Ingår i: Experimental gerontology. - : Elsevier BV. - 1873-6815 .- 0531-5565. ; 44:9, s. 579-85
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Alzheimer's Disease Neuroimaging Initiatives ("ADNI") aim to validate neuroimaging and biochemical markers of Alzheimer's disease (AD). Data of the pilot European-ADNI (E-ADNI) biological marker programme of cerebrospinal fluid (CSF) and plasma candidate biomarkers are reported. METHODS: Six academic EADC centres recruited 49 subjects (healthy controls, subjects with mild cognitive impairment (MCI) and AD). We measured CSF beta-amyloid 42 (CSF Abeta42), total tau-protein (t-tau), phosphorylated tau-proteins (P-tau181, P-tau231), plasma beta-amyloid 40 and 42 (Abeta40/Abeta42). Immediate fresh shipment was compared to freezing and later shipment on dry ice. RESULTS: CSF T-tau (fresh samples) was increased in AD versus controls (p=0.049), CSF Abeta42 (frozen samples) was decreased in MCI and AD (p=0.02), as well as plasma Abeta40 (fresh and frozen samples) in AD (p=0.049 and p=0.016). Pooled values of neurochemical parameters and ratios thereof were different between centres (p<0.005). Analysis of frozen samples yielded higher diagnostic accuracy than immediate fresh shipment with 100% (fresh: 100%) correctly classified in control subjects, 100% (78%) in MCI, 91% (91%) in AD. CONCLUSION: The use of frozen rather than fresh samples renders higher diagnostic accuracy within a multicentre context. We confirmed the feasibility of a multicentre AD biomarker programme for future clinical trials.
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| 10. |
- Cacciani, Nicola, et al.
(författare)
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Age related differences in diaphragm muscle fiber response to mid/long term controlled mechanical ventilation
- 2014
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Ingår i: Experimental Gerontology. - : Elsevier BV. - 0531-5565 .- 1873-6815. ; 59, s. 28-33
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Critically ill intensive care patients are subjected to controlled mechanical ventilation (CMV) which has an important association in triggering the impaired muscle function and the consequent delayed weaning from the respirator. AIM: The main aim of this study was to measure the effects of age and CMV over a period up to 5days on rat diaphragm muscle fibers, more specifically focusing on the changes in fiber structure and function. METHODS: Diaphragm muscle fiber cross-sectional area (CSA) and force generating capacity were measured in young (6months) and old (28-32months) rats in response to five days of CMV. To investigate the biological age of the old rats in this rat strain (F344 BN hybrid), a second set of experiments comparing muscle fiber size and specific force (maximum force normalized to CSA) was investigated in fast- and slow-twitch distal hind limb muscles in 3 different age groups: young adults (6months), middle aged (18months) and old rats (28months). RESULTS: This study shows an unexpected response of the diaphragm fibers to 5days CMV, demonstrating an increased CSA (p<0.001) in both young and old animals. Furthermore, an observed decreased maximum force of 39.8-45.2% (p<0.001) in both young and old animals compared with controls resulted in a dramatic loss of specific force. We suggest that this increase in CSA and decrease in specific force observed in both the young and old diaphragm fibers is an ineffective compensatory hypertrophy in response to the CMV. These results demonstrate an important mechanism of significant importance for the weaning problems associated with mechanical ventilation.
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