252 research outputs found
AIDS And The Funeral Industry In Southeastern Africa
This paper examines the impact of AIDS on the Funeral Industry in Southeastern Africa. It first presents an overview of AIDS in Southeastern Africa and then it delves into an examination of family funeral customs in select countries and how they have been affected by the AIDS epidemic. These countries include: Zimbabwe, Malawi, Zambia, South Africa, Botswana, and Uganda. Next, this paper takes a look at the impact of AIDS on hospital mortuaries in Zimbabwe. This is followed by an examination of the rise in the number of orphans along with the effect of AIDS on the classroom setting. Finally, four suggestions for fighting the disease are presented
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The Onset of H + Ketene Products from Vinoxy Radicals Prepared by Photodissociation of Chloroacetaldehyde at 157 nm
We investigate the unimolecular dissociation of the vinoxy radical (CH2CHO) prepared with high internal energy imparted from the photodissociation of chloroacetaldehyde (CH2ClCHO) at 157 nm. Using a velocity map imaging apparatus, we measured the speed distribution of the recoiling chlorine atoms, Cl(2P3/2) and Cl(2P1/2), and derived from this the resulting distribution of kinetic energy, P(ET), imparted to the Cl + vinoxy fragments upon dissociation. Using conservation of energy, the distribution of kinetic energy was used to determine the total internal energy distribution in the radical. The P(ET) derived for the C–Cl bond fission presented in this work suggests the vinoxy radicals are mostly formed in the à state. We also took ion images at m/z = 42 and m/z = 15 to characterize the branching between the unimolecular dissociation channels of the vinoxy radical to H + ketene and methyl + CO products. Our results show a marked change in the branching ratio between the two channels from the previous study on the photodissociation of chloroacetaldehyde at 193 nm by Miller et al. (J. Chem. Phys., 2004, 121, 1830) in that the production of ketene is now favored over the production of methyl. To help analyze the data, we developed a model for the branching between the two channels that takes into account how the change in rotational energy en route to the products affects the vibrational energy available to surmount the barriers to the channels. The model predicts the portion of the C–Cl bond fission P(ET) that produces dissociative vinoxy radicals, then predicts the branching ratio between the H + ketene and CH3 + CO product channels at each ET. The model uses Rice–Ramsperger–Kassel–Marcus rate constants at the correct sums and densities of vibrational states while accounting for angular momentum conservation. We find that the predicted portion of the P(ET) that produces H + ketene products best fits the experimental portion (that we derive by taking advantage of conservation of momentum) if we use a barrier height for the H + ketene channel that is 4.0 ± 0.5 kcal/mol higher than the isomerization barrier en route to CH3 + CO products. Using the G4 computed isomerization barrier of 40.6 kcal/mol, this gives an experimentally determined barrier to the H + ketene channel of 44.6 kcal/mol. From these calculations, we also predict the branching ratio between the H + ketene and methyl + CO channels to be ∼2.1:1
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A study of glycaemic effects following acute anthocyanin-rich blueberry supplementation in healthy young adults
The postprandial response to ingested carbohydrate is recognised as a marker of metabolic health. Postprandial hyperglycaemia is observed in type 2 diabetes mellitus and is a significant risk factor for cardiovascular disease. Cognitive deficits are also associated with type 2 diabetes. Therefore interventions which moderate postprandial glucose profiles are desirable. Here we investigated the impact of anthocyanin-rich wild blueberries on postprandial glucose response. Seventeen healthy young adults consumed a range of doses of freeze-dried wild blueberry powder, in smoothie form, in both sugar-matched and no-added-sugar conditions. Plasma glucose was determined by a capillary sampling method at baseline and at regular intervals up to 2.5 hours postprandially. Blueberries were observed to significantly extend the postprandial glucose response beyond the period observed for a sugar-matched control,
characteristic of a beneficial glycaemic response. Furthermore, blueberries were observed to reduce peak
postprandial glucose levels, although statistical significance was not achieved. The findings suggest a tempering of the postprandial glucose response in the presence of anthocyanin-rich blueberry, and are discussed
with reference to likely glucoregulatory mechanisms of action and their implications for cognitive and type 2 diabetes research
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Stereopsis in end-stage renal disease (ESRD)
We investigated an effect of end-stage renal disease (ESRD) on the visual system by measuring the ability of 21 patients to perceive depth in the random dot stereograms and circles of the Randot Test. To control for other factors which might influence performance on the tests of stereopsis, patients were compared with healthy controls matched for age, years of education, IQ, and general cognitive ability. Vernier acuity (thought to reflect mainly central processing) and Landolt acuity (more sensitive to retinal and optical abnormalities) were also measured, but the study did not include a formal ophthalmological examination. All controls could perceive depth in random dot stereograms, whereas 9/21 patients could not. Patients who could perceive depth had worse stereoacuity than did their matched controls. The patient group as a whole had worse Vernier and Landolt acuities than the controls. The stereoblind patient subgroup had similar Vernier acuity to the stereoscopic subgroup, but worse Landolt acuity, and were more likely to have peripheral vascular disease. We conclude that ESRD had affected structures both within the eye, and within the visual brain. However, the similarity of Vernier acuity and difference of Landolt acuity in the stereoblind and stereoscopic patient subgroups suggest that the differences in stereoscopic ability arise from abnormalities in the eyes rather than in the brain
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Latent learning in end stage renal disease (ESRD)
Cognitive functions such as attention and memory are known to be impaired in End Stage Renal Disease (ESRD), but the sites of the neural changes underlying these impairments are uncertain. Patients and controls took part in a latent learning task, which had previously shown a dissociation between patients with Parkinson’s disease and those with medial temporal damage. ESRD patients (n=24) and age and education-matched controls (n=24) were randomly assigned to either an exposed or unexposed condition. In Phase 1 of the task, participants learned that a cue (word) on the back of a schematic head predicted that the subsequently seen face would be smiling. For the exposed (but not unexposed) condition, an additional (irrelevant) colour cue was shown during presentation. In Phase 2, a different association, between colour and facial expression, was learned. Instructions were the same for each phase: participants had to predict whether the subsequently viewed face was going to be happy or sad. No difference in error rate between the groups was found in Phase 1, suggesting that patients and controls learned at a similar rate. However, in Phase 2, a significant interaction was found between group and condition, with exposed controls performing significantly worse than unexposed (therefore demonstrating learned irrelevance). In contrast, exposed patients made a similar number of errors to unexposed in Phase 2. The pattern of results in ESRD was different from that previously found in Parkinson’s disease, suggesting a different neural origin
Flavonoid-Rich Mixed Berries Maintain and Improve Cognitive Function Over a 6h Period in Young Healthy Adults
Research with young adults has previously indicated flavonoid-rich berry interventions facilitate improved executive function (EF) and positive affect 20 min–2 h post-dosing. There has been little consideration of the impact of a berry intervention over a working day and interventions have also tended to consider only a single berry type. This study investigated the temporal profile of EF and mood changes over a 6 h period following a mixed-berry intervention. We hypothesized berry-related benefits would be most evident when participants were cognitively compromised on demanding elements of the task or during periods of fatigue. The study employed a single-blind, randomized, placebo controlled, between-subjects design. Forty participants aged 20–30 years consumed a 400 mL smoothie containing equal blueberry, strawberry, raspberry, and blackberry (n = 20) or matched placebo (n = 20). Mood was assessed using the Positive and Negative Affect Schedule; EF was tested using the Modified Attention Network (MANT) and Task Switching (TST) Tasks. Testing commenced at baseline then 2, 4 and 6 h post-dosing. As expected, following placebo intervention, performance decreased across the day as participants became cognitively fatigued. However, following berry intervention, participants maintained accuracy on both cognitive tasks up to and including 6 h, and demonstrated quicker response times on the MANT at 2 and 4 h, and TST at 6 h. This study demonstrates the efficacy of flavonoid rich berries in maintaining or improving cognitive performance across the 6 h day
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Effects of High Angular Momentum on the Unimolecular Dissociation of CD<sub>2</sub>CD<sub>2</sub>OH: Theory and Comparisons with Experiment
This paper explores the dynamics of a highly rotationally and vibrationally excited radical, CD2CD2OH. The radical is produced from the 193 nm photodissociation of 2-bromoethanol-d4, so it is imparted with high angular momentum and high vibrational energy and subsequently dissociates to several product channels. This paper focuses on characterizing its angular momentum and modeling its effect on the product channels, including the HOD + vinyl-d3 product channel resulting from a frustrated dissociation of the radical originally en route to OH + ethene-d4 that instead results in D atom abstraction. Our impulsive model of the initial photodissociation shows that, for some cases, upward of 200 au of angular momentum is imparted, which greatly affects the dynamics of the competing product channels. Using a permutationally invariant potential energy surface and quasiclassical trajectories, we simulated the dissociation dynamics of CD2CD2OH and compared these results to those of Kamarchik et al. (J. Phys. Chem. Lett.2010, 1, 3058–3065), who studied the dynamics of CH2CH2OH with zero angular momentum. We found that the recoil translational energy distribution for radicals that dissociated to OH + C2D4 matched experiment closely only when high angular momentum of the initial radical was explicitly included in the trajectory calculations. Similarly, the rate constant for dissociation changes when rotational energy was added to the vibrational energy in the initial conditions. Lastly, we applied the sketch-map dimensionality reduction technique to analyze mechanistic information leading to the vinyl + water product channel. Projecting the ab initio intrinsic reaction coordinates onto the lower dimensional space identified with sketch map offers new insight into the dynamics when one looks at the simulated trajectories in the lower dimensional space. Further analysis shows that the transition path resembles a frustrated dissociation of the OH + ethene radical adduct, followed instead by branching to vinyl + water when the leaving OH group encounters a nearby D atom on the ethene moiety. This characterization is in accord with the one made previously. We show that the transition path bifurcation between the two similar channels occurs at carbon–oxygen distances and oxygen-abstracted deuterium distances of 2–2.5 Å controlled by the C–O–D bond angle with large angles preferentially branching to the water plus vinyl product state. The experimental branching ratios were not reproduced by theory, however, due partly to the insufficient quality of the fitted potential surface. We also have evidence of a minor product channel, HD + vinoxy-d3, from our molecular dynamics simulations that allows us to assign the HD signal in prior experimental work
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A potential barrier to adherence? Memory for future intentions is impaired in hemodialysis patients
Introduction: End-stage renal disease (ESRD) has been associated with a range of cognitive deficits, including impaired retrospective memory and attention. Prospective Memory (PM) is memory for future intentions, such as remembering to take medication on time. PM has not been examined in any ESRD patients, yet the implications upon diet and medication management could have potentially detrimental effects on patient welfare. This is the first study to examine PM in ESRD patients being treated with hemodialysis (HD).
Methods: HD patients (n=18) were compared to age and education-matched controls (n=18) on a boardgame task that emulates a typical week of activities (i.e. grocery shopping, meetings with friends), requiring the participant to remember a series of upcoming tasks. Other measures were also examined, including general cognitive decline, measures of independent living, IQ and mood.
Findings: Patients recalled significantly fewer upcoming events than the control group, suggesting an impairment of PM. No significant relationship was found between PM performance and any other measures, suggesting the difference between groups is likely due to the effects of ESRD, HD treatment or some associated comorbidity.
Discussion: This is the first study to demonstrate a PM deficit in patients undergoing HD treatment. This finding contributes to the current knowledge of the cognitive profile of patients undergoing HD, whilst also highlighting the implications that a PM deficit may have on patient quality of life. The finding may go some way to explaining variances in patients’ ability to monitor and adhere to medication and dietary regimes, and ultimately, to live independently. The study also highlights the necessity of viewing treatment for ESRD as a holistic process to maximise patient wellbeing
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