845 research outputs found
Diagnosis and management of transient ischaemic attack and ischaemic stroke in the acute phase
Time spent at home poststroke: “home-time” a meaningful and robust outcome measure for stroke trials
<p><b>Background and Purpose:</b> Stroke outcome assessment requires some measure of functional recovery. Several instruments are in common use but all have recognized limitations. We examined duration of stay in the patient’s own home over the first 90 days since stroke—"home-time"—as an alternative outcome likely to show graded response with improved reliability.</p>
<p><b>Methods:</b> We examined prospectively collected data from the GAIN International trial using analysis of variance with Bonferroni contrasts of adjacent modified Rankin scale score categories.</p>
<p><b>Results:</b> We had full outcome data from 1717 of 1788 patients. Increasing home-time was associated with improved modified Rankin scale scores (P<0.0001). The relationship held across all modified Rankin scale grades except 4 to 5.</p>
<p><b>Conclusions:</b> Home-time offers a robust, useful, and easily validated outcome measure for stroke, particularly across better recovery levels.</p>
Deriving modified rankin scores from medical records
<p><b>Background and Purpose:</b> Modified Rankin score (mRS) is traditionally graded using a face-to-face or telephone interview. Certain stroke assessment scales can be derived from a review of a patient’s case-record alone. We hypothesized that mRS could be successfully derived from the narrative within patient case-records.</p>
<p><b>Methods:</b> Sequential patients attending our cerebrovascular outpatient clinic were included. Two independent, blinded clinicians, trained in mRS, assessed case-records to derive mRS. They scored “certainty” of their grading on a 5-point Likert scale. Agreement between derived and traditional face-to-face mRS was calculated using attribute agreement analysis.</p>
<p><b>Results:</b> Fifty patients with a range of disabilities were included. Case-record appraisers were poor at deriving mRS (k=0.34 against standard). Derived mRS grades showed poor agreement between observers (k=0.33). There was no relationship between certainty of derived mRS and proportion of correct grades (P=0.727).</p>
<p><b>Conclusion:</b> Accurate mRS cannot be derived from standard hospital records. Direct mRS interview is still required for clinical trials.</p>
Concrete pavements as a source of heating and cooling
There is great potential to use the large open space of pavement structures, equipped with an embedded pipe network, in conjunction with a heat pump, to provide heating and cooling for adjacent buildings, e.g. airport terminals, shopping centres etc, here termed a Pavement Source Heat Pump (PSHP). Due to the high thermal mass of pavement materials, seasonal temperature fluctuation under the pavement is much less than the temperature fluctuation of ambient air. Therefore, pavements can be utilised as a low grade heat source during winter and as a heat sink during summer. Airports, for example, provide a key potential application as they are very large consumers of energy, typically have very high cooling demands, have a large amount of adjacent pavement area, and are of a similar arrangement throughout the world. In this paper, the temperature distribution into pavements with different thermo-physical properties was modelled in order to evaluate their effects on depth of seasonal temperature fluctuation. The results show that there is a linear relationship between the thermal diffusivity and depth of seasonal temperature fluctuation and it decreases in relation to the thermal diffusivity of the pavement
Allopurinol use yields potentially beneficial effects on inflammatory indices in those with recent ischemic stroke: a randomized, double-blind, placebo-controlled trial
<p><b>Background and Purpose</b>: Elevated serum uric acid level is associated with poor outcome and increased risk of recurrent events after stroke. The xanthine oxidase inhibitor allopurinol lowers uric acid but also attenuates expression of inflammatory adhesion molecules in murine models, reduces oxidative stress in the vasculature, and improves endothelial function. We sought to investigate whether allopurinol alters expression of inflammatory markers after acute ischemic stroke.</p>
<p><b>Methods</b>: We performed a randomized, double-blind, placebo-controlled trial to investigate the safety, tolerability, and effect of 6 weeks’ treatment with high- (300 mg once a day) or low- (100 mg once a day) dose allopurinol on levels of uric acid and circulating inflammatory markers after ischemic stroke.</p>
<p><b>Results</b>: We enrolled 50 patients with acute ischemic stroke (17, 17, and 16 in the high, low, and placebo groups, respectively). Mean (±SD) age was 70 (±13) years. Groups had similar characteristics at baseline. There were no serious adverse events. Uric acid levels were significantly reduced at both 7 days and 6 weeks in the high-dose group (by 0.14 mmol/L at 6 weeks, P=0.002). Intercellular adhesion molecule-1 concentration (ng/mL) rose by 51.2 in the placebo group, rose slightly (by 10.6) in the low-dose allopurinol group, but fell in the high-dose group (by 2.6; difference between groups P=0.012, Kruskal-Wallis test).</p>
<p><b>Conclusion</b>: Allopurinol treatment is well tolerated and attenuates the rise in intercellular adhesion molecule-1 levels seen after stroke. Uric acid levels were lowered with high doses. These findings support further evaluation of allopurinol as a preventive measure after stroke.</p>
Association between disability measures and healthcare costs after initial treatment for acute stroke
<p><b>Background and Purpose:</b> The distribution of 3-month modified Rankin scale (mRS) scores has been used as an outcome measure in acute stroke trials. We hypothesized that hospitalization and institutional care home stays within the first 90 days after stroke should be closely related to 90-day mRS, that each higher mRS category will reflect incremental cost, and that resource use may be less clearly linked to the National Institutes of Health Stroke Scale (NIHSS) or Barthel index.</p>
<p><b>Methods:</b> We examined resource use data from the GAIN International trial comparing 90-day mRS with total length of stay in hospital or other institutions during the first 90 days. We repeated analyses using NIHSS and Barthel index scores. Relationships were examined by analysis of variance (ANOVA) with Bonferroni contrasts of adjacent score categories. Estimated costs were based on published Scottish figures.</p>
<p><b>Results:</b> We had full data from 1717 patients. Length of stay was strongly associated with final mRS (P<0.0001). Each mRS increment from 0 to 1–2 to 3–4 was significant (mean length of stay: 17, 25, 44, 58, 79 days; P<0.0005). Ninety-five percent confidence limits for estimated costs (£) rose incrementally: 2493 to 3412, 3369 to 4479, 5784 to 7008, 7300 to 8512, 10 095 to 11 141, 11 772 to 13 560, and 2623 to 3321 for mRS 0 to 5 and dead, respectively. Weaker relationships existed with Barthel and NIHSS.</p>
<p><b>Conclusions:</b> Each mRS category reflects different average length of hospital and institutional stay. Associated costs are meaningfully different across the full range of mRS outcomes. Analysis of the full distribution of mRS scores is appropriate for interpretation of treatment effects after acute stroke and more informative than Barthel or NIHSS end points.</p>
The environmental context of the Neolithic monuments on the Brodgar Isthmus, Mainland, Orkney
This work was funded in part by Historic Environment Scotland.The World Heritage Sites of Orkney, Scotland contain iconic examples of Neolithic monumentality that have provided significant information about this period of British prehistory. However, currently, a complete understanding of the sites remains to be achieved. This is, in part, because the monuments lack an adequate context within the broader palaeolandscape. Recent investigations (seismic geophysical survey, microfossil analysis and 14C dating) in and around the Brodgar Isthmus, both onshore and offshore, are used to reconstruct the landscapes at a time when sea-level, climate and vegetation were different to that experienced today. Results show that in the early Neolithic the isthmus between the Ring of Brodgar and Stones of Stenness was broader with a smaller loch to the west. Furthermore this landscape contained sandstone outcrops that would have provided a potential source of stone for monument construction. Microfossil analysis and radiocarbon dates demonstrate that the Loch of Stenness was transformed from freshwater to brackish during the early Neolithic, perhaps immediately preceding construction of the major monuments. Finally, the analysis of our data suggests that sediment influx to the loch shows a tenfold increase coincident with widespread vegetation change that straddles the Mesolithic/Neolithic transition at c. 8 ka cal. B.P. These results provide, for the first time, a landscape context for the Neolithic sites on the isthmus.PostprintPeer reviewe
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Bed material agglomeration during fluidized bed combustion. Technical progress report, April 1, 1995--June 30, 1995
During this quarter, agglomeration tests were conducted in a laboratory-scale fluidized bed combustor using coal and {open_quotes}model{close_quotes} components which allowed controlled amounts of clays and pyrites to be added during the test. These tests permitted a more direct evaluation of the interaction between iron compounds and aluminosilicates. With additional clay and pyrite (under simulated local reducing conditions found at coal feed locations) large agglomerates formed. The agglomerates were many times larger than those formed with a standard coal feed. When only clay was added to the fuel (no additional pyrite), agglomerates formed but they were much smaller and very friable. These tests support the hypothesis that local reducing conditions promote the interaction of iron in a +2 state and aluminosilicate material in the coal which leads to agglomeration during fluidized bed combustion. Also during this quarter, a deposit which formed in a fluidized bed boiler of a Texas-New Mexico Power Company was analyzed to determine the chemical and mineralogic mechanisms responsible for deposit formation. Mineral phases were determined by x-ray diffraction (XRD). Bulk chemical composition was determined by x-ray fluorescence spectroscopy (XRF). Polished sections of the deposit were made for optical and scanning electron microscopy
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Bed material agglomeration during fluidized bed combustion. Final report
The purpose of this project is to determine the physical and chemical reactions which lead to the undesired agglomeration of bed material during fluidized bed combustion of coal and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed combustors (FBCs) indicate that at least five boilers were experiencing some form of bed material agglomeration. Deposit formation was reported at nine sites with deposits most commonly at coal feed locations and in cyclones. Other deposit locations included side walls and return loops. Three general types of mineralogic reactions were observed to occur in the agglomerates and deposits. Although alkalies may play a role with some {open_quotes}high alkali{close_quotes} lignites, we found agglomeration was initiated due to fluxing reactions between iron (II) from pyrites and aluminosilicates from clays. This is indicated by the high amounts of iron, silica, and alumina in the agglomerates and the mineralogy of the agglomerates. Agglomeration likely originated in the dense phase of the FBC bed within the volatile plume which forms when coal is introduced to the boiler. Secondary mineral reactions appear to occur after the agglomerates have formed and tend to strengthen the agglomerates. When calcium is present in high amounts, most of the minerals in the resulting deposits are in the melilite group (gehlenite, melilite, and akermanite) and pyroxene group (diopside and augite). During these solid-phase reactions, the temperature of formation of the melilite minerals can be lowered by a reduction of the partial pressure of CO{sub 2} (Diopside + Calcite {r_arrow}Akermanite)
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