Measurements of Fungal Activity as a Function of Relative Humidity by Isothermal Microcalorimetry

The heat produced by the metabolism of a mould fungus (Penicillium brevicompactum) growing on softwood was measured by isothermal calorimetry under different relative humidity (RH) levels during desorption (from 95% to 65% RH) and absorption (from 65% to 95% RH). The humidification method was successful and it was possible to decrease and increase the relative humidity and moisture content in small steps. The calorimetric measurements were difficult to interpret as the thermal power was not constant at most levels. However, a general trend with lowered activity at lower relative humidity was seen. Calorimetry can possibly be used in mapping dynamic mould activity under changing environmental conditions and can therefore be applied in predicting the risk of mould in buildings

Airborne Advanced Reconfigurable Computer System (ARCS)

A digital computer subsystem fault-tolerant concept was defined, and the potential benefits and costs of such a subsystem were assessed when used as the central element of a new transport's flight control system. The derived advanced reconfigurable computer system (ARCS) is a triple-redundant computer subsystem that automatically reconfigures, under multiple fault conditions, from triplex to duplex to simplex operation, with redundancy recovery if the fault condition is transient. The study included criteria development covering factors at the aircraft's operation level that would influence the design of a fault-tolerant system for commercial airline use. A new reliability analysis tool was developed for evaluating redundant, fault-tolerant system availability and survivability; and a stringent digital system software design methodology was used to achieve design/implementation visibility

Integrated effect of thermal ageing and low flux irradiation on microstructural evolution of the ferrite of welded austenitic stainless steels

With the purpose to quantify microstructural changes with respect to ageing degradation, the microstructure of aged type 308 stainless steel welds with a ferrite content of 5-7% has been analysed using atom probe tomography. The weld metal of the core barrel of a decommissioned light water reactor, irradiated during operation of the reactor to 0.1 dpa, 1 dpa and 2 dpa at 280-285\ub0C (231,000 h), are compared to two similar thermally aged welds. In the ferrite of the irradiated welds, there is spinodal decomposition into Cr-rich α’ and Fe-rich α, with a similar degree of decomposition for all investigated doses, amplitudes of 21-26% and wavelengths between 6 and 9 nm. The ferrite of the thermally aged material showed evidence of decomposition when aged at 325\ub0C (an amplitude of 13-14% and wavelength of 5 nm), but not when aged at 291\ub0C, thus the irradiation significantly increases the rate of spinodal decomposition. There is G-phase (Ni Si Mn ) precipitation in the ferrite of all the weld metals except the one that was thermally aged at the lowest temperature. After irradiation to 1 and 2 dpa, the G-phase is considerably more well developed than after 0.1 dpa or thermal ageing

Development of a sensitive and rapid method for the measurement of total microbial activity using fluorescein diacetate (FDA) in a range of soils

Fluorescein diacetate (FDA) hydrolysis is widely accepted as an accurate and simple method for measuring total microbial activity in a range of environmental samples, including soils. Colourless fluorescein diacetate is hydrolysed by both free and membrane bound enzymes, releasing a coloured end product fluorescein which can be measured by spectrophotometry. The current method for measuring FDA hydrolysis in soils is limited in its application. FDA activity was very low in sandy and clayey soils. The low activity observed for these soil types was made difficult to measure by the original authors choice of solvent for terminating the hydrolysis reaction. Acetone (50% v/v) was found to be most efficient at stopping the hydrolysis reaction. During this study acetone (50% v/v) was found to cause a decrease of approximately 37% in the absorbance of fluorescein produced by the soil samples measured. Although this colour loss is independent of initial fluorescein concentration, it makes the measurement of FDA hydrolytic activity extremely difficult in soils with low microbial activity i.e. sandy and/or clayey soils. Chloroform/methanol (2:1 v/v) was found to successfully stop the hydrolysis reaction for up to 50 min in a range of soil samples without causing the loss of colour observed with acetone. By changing the solvent used for terminating the hydrolysis reaction, low activity soils could be measured successfully. Other parameters of the hydrolysis reaction were optimised for the measurement of soil samples including effect of pH. optimum temperature of incubation, amount of soil, time of incubation, amount of substrate and preparation of suitable standards. A new, more sensitive method is proposed adapted from the original method, which provides a more accurate determination of FDA hydrolysis in a wide range of soils

Risk of myocardial infarction at specific troponin T levels using the parameter predictive value among lookalikes (PAL)

AbstractBackgroundMyocardial infarction is more likely if the heart damage biomarker cardiac troponin T (cTnT) is elevated in a blood sample, indicating that cardiac damage has occurred. No method allows the clinician to estimate the risk of myocardial infarction at a specific cTnT level in a given patient.MethodsPredictive value among lookalikes (PAL) uses pre-test prevalence, sensitivity and specificity at adjacent cTnT limits based on percentiles. PAL is the pre-test prevalence-adjusted probability of disease between two adjacent cTnT limits. If a chest pain patient's cTnT level is between these limits, the risk of myocardial infarction can be estimated.ResultsThe PAL based on percentiles had an acceptable sampling error when using 100 bootstrapped data of 18 different biomarkers from 38,945 authentic lab measurements. A PAL analysis of an emergency room cohort (n=11,020) revealed that the diagnostic precision of a high-sensitive cTnT assay was similar among chest pain patients at different ages. The higher incidence of false positive results due to non-specific increases in cTnT in the high-age group was counterbalanced by a higher pre-test prevalence of myocardial infarction among older patients, a finding that was missed when using a conventional ROC plot analysis.ConclusionsThe PAL was able to calculate the risk of myocardial infarction at specific cTnT levels and could complement decision limits

Assessment of a multi-marker risk score for predicting cause-specific mortality at three years in older patients with heart failure and reduced ejection fraction

Background: Due to increasing co-morbidity associated with aging, heart failure (HF) has become more prevalent and heterogeneous in older individuals, and non-cardiovascular (CV) mortality has increased. Previously, we defined a multi-marker modality that included cystatin C (CysC), troponin T (TnT), and age. Here, we validated this multi-marker risk score by evalu­ating its predictions of all-cause mortality and CV mortality in an independent population of older individuals with HF and reduced ejection fraction (HFrEF). Methods: This prospective cohort study included 124 patients, median age 73 years, that had HFrEF. We determined all-cause mortality and CV mortality at a 3-year follow-up. We com­pared the risk score to the N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) for predicting all-cause mortality and CV mortality. Results: High risk scores were associated with both all-cause mortality (HR 4.2, 95% CI 2.2–8.1, p < 0.001) and CV mortality (HR 3.6, 95% CI 1.7–8.0, p = 0.0015). Receiver ope­rating characteristics showed similar efficacy for the risk score and NT-proBNP in predicting all-cause mortality (HR 0.74, 95% CI 0.65–0.81 vs. HR 0.74, 95% CI 0.65–0.81, p = 0.99) and CV mortality (HR 0.68, 95% CI 0.59–0.76 vs. HR 0.67, 95% CI 0.58–0.75, p = 0.95). When the risk score was added to the NT-proBNP, the continuous net reclassification impro­vement was 56% for predicting all-cause mortality (95% CI 18–95%, p = 0.004) and 45% for predicting CV mortality (95% CI 2–89%, p = 0.040). Conclusions: In HFrEF, a risk score that included age, TnT, and CysC showed efficacy similar to the NT-proBNP for predicting all-cause mortality and CV mortality in an older population.

Decreased admissions and hospital costs with a neutral effect on mortality following lowering of the troponin T cutoff point to the 99th percentile

Background: The implementation of high-sensitivity cardiac troponin T (hs-cTnT) assays and a cutoff based on the 99th cTnT percentile in the evaluation of patients with suspected acute coronary syndrome has not been uniform due to uncertain effects on health benefits and utilization of limited resources. Methods: Clinical and laboratory data from patients with chest pain or dyspnea at the emergency de¬partment (ED) were evaluated before (n = 20516) and after (n = 18485) the lowering of the hs-cTnT cutoff point from 40 ng/L to the 99th hs-cTnT percentile of 14 ng/L in February 2012. Myocardial infarction (MI) was diagnosed at the discretion of the attending clinicians responsible for the patient. Results: Following lowering of the hs-cTnT cutoff point fewer ED patients with chest pain or dyspnea as the principal complaint were analyzed with an hs-cTnT sample (81% vs. 72%, p < 0.001). Overall 30-day mortality was unaffected but increased among patients not analyzed with an hs-cTnT sample (5.3% vs. 7.6%, p < 0.001). The MI frequency was unchanged (4.0% vs. 3.9%, p = 0.72) whereas admission rates decreased (51% vs. 45%, p < 0.001) as well as hospital costs. Coronary angiographies were used more frequently (2.8% vs. 3.3%, p = 0.004) but with no corresponding change in coronary interventions. Conclusions: At the participating hospital, lowering of the hs-cTnT cutoff point to the 99th percentile decreased admissions and hospital costs but did not result in any apparent prognostic or treatment benefits for the patients

Determination of fungal activity in modified wood by means of micro-calorimetry and determination of total esterase activity

Beech and pine wood blocks were treated with 1,3-dimethylol-4,5-dihydroxyethylen urea (DMDHEU) to increasing weight percent gains (WPG). The resistance of the treated specimens against Trametes versicolor and Coniophora puteana, determined as mass loss, increased with increasing WPG of DMDHEU. Metabolic activity of the fungi in the wood blocks was assessed as total esterase activity (TEA) based on the hydrolysis of fluorescein diacetate and as heat or energy production determined by isothermal micro-calorimetry. Both methods revealed that the fungal activity was related with the WPG and the mass loss caused by the fungi. Still, fungal activity was detected even in wood blocks of the highest WPG and showed that the treatment was not toxic to the fungi. Energy production showed a higher consistency with the mass loss after decay than TEA; higher mass loss was more stringently reflected by higher heat production rate. Heat production did not proceed linearly, possibly due to the inhibition of fungal activity by an excess of carbon dioxide