First Year Of Exposure Research Articles

Corrosion behaviour of Ni and nickel aluminide coatings exposed in a biomass fired power plant for two years

Ni and Ni2Al3 coatings were applied to superheater tubes that were built into a wood-fired boiler with an outlet steam temperature of 520 °C. The present paper evaluates the performance of the coatings after two years of service. The corrosion performance of the coatings is discussed with respect to the temperature histograms and deposit composition and compared to the performance of the coatings after the first year. The Ni coatings showed extremely protective behaviour for 1 year however after 2 years exposure, the Ni coating was chemically attacked, thick NiO was formed and sulphur containing precipitates were present at the base of the Ni layer indicating grain boundary ingress of corrosive species. For the Ni2Al3 coatings, localized attack was observed after the first year of exposure, but after two years no intact nickel aluminide coatings were observed.

Optimum selection of zinc-coated cable trunking systems for electrical installations based on atmospheric corrosion prediction

The study presents a methodology for the optimum selection of the most suitable zinc-based coatings in metallic trunking systems to fulfill the requirements related to atmospheric corrosion resistance. The current methodologies are based on heuristic procedures that do not consider the influence of the in situ atmospheric conditions, which are the main cause of most of the corrosion problems. The effect of corrosion over time is generally estimated using a logarithmic function, which depends on corrosion during the first year of exposure, as well as on environmental parameters (e.g. temperature, humidity, pollutants, etc.). Different mathematical models for the prediction of corrosion during the first year of exposure were analyzed. Ten of these models were selected and compared with actual tests determining the model that best fitted the actual values. From this first-year corrosion value, the long-term corrosion function was calculated for each relevant commercial coating. Finally, a case study was analyzed by means of the proposed methodology. The results show the importance of the corrosion function and its influence in the selection of the coating to minimize costs.

The Diesel Exhaust in Miners Study provides no evidence for an increase in risk for lung cancer in miners exposed to diesel engine emissions

The Diesel Exhaust in Miners Study is unquestionably the most suitable data material to date to examine a possible link between diesel engine emissions and lung cancer risk. But the results do not appear to be consistent in themselves. The crucial methodological problem in this study, however, has yet to be discovered, to which the lack of any description of age related information (year of birth, year of hire, year of first exposure, year of death) for the cohort as well as for the cases might have contributed. This information is important to understand the flaws in the analysis. It turns out that the year of birth is associated with the exposure, i.e. with the chance to be exposed over a certain period of time as well as with the chance to be an ever-smoker. A further important issue for the interpretation of the results is the validity of the data on smoking, which are mainly obtained from next of kin for decedents up to 50 years after death. Taking all these aspects into account, it can be concluded that only the SMR-analysis can be considered from all published results.

On the Use of Location and Occupancy Factors for Estimating External Exposure From Deposited Radionuclides.

Providing a dose estimate for the exposed population is crucial in the case of deposition of a known radioactive material, either through an accident or during routine operations. In the absence of detailed information on each individual, knowing the demographics of the affected population concerning occupational habits and housing allows the determination and use of appropriate location and occupancy factors required for exposure and dose calculations. The previous approach in the United Nations Scientific Committee on the Effects of Atomic Radiation 2013 report, published in 2014, used time-dependent location factors and occupancy factors based on age and occupation. The newly published methodology in the United Nations Scientific Committee on the Effects of Atomic Radiation 2016 report (2017) is simplified, using a single time-independent location factor for indoor occupancy, as well as a single occupancy factor that is independent of the age and occupation of the population considered. In this work the two approaches are compared for different population groups and housing types in the case of both a short-lived and a long-lived radionuclide. It was found that the new simplified methodology, while overestimating the integrated effective dose over 100 y for Cs and Cs, also underestimates the dose on short timescales, especially for the shorter-lived Cs. Additionally, the dose rate is significantly underestimated for certain types of buildings with higher location factors. This was found for both radionuclides in the first year of exposure. In the case of short-lived Cs, the integrated effective dose after 100 y is also underestimated in certain cases. It can be concluded that, while the simplified methodology can reasonably and successfully be applied in cases where dose due to deposition (1) is not the dominant pathway and (2) is part of multistep calculations, caution must be exercised in more complex exposure situations, especially when performing dose assessment in response to an accident.

Application of growth rings and scars in exposed roots of Schizolobium parahyba as a tool for dating geomorphic processes in the State of São Paulo, Brazil

Water erosion is an important degradation process, which results in loss of soil, reduction in agricultural productivity, and causes severe environmental impact. Dendrogeomorphology has methods in which the structure of the wood of the stem and roots of tree and shrub species affected by sediment deposition or by root exposure is analysed, to establish the chronology of erosive events. The objective of the present work was to describe the modifications and scar formation in Schizolobium parahyba growth rings, attributed to the effect of roots exposure for determining the first year of exposure. The study area presents erosion features, such as gullies, with the consequent exposure of tree roots. The growth rings and the scars formed by the flow of water and soil particles were analysed in cross-sections of exposed roots to date the erosion processes. This paper demonstrates the potential of S. parahyba for dendrogeomorphological studies, validating dendrogeomorphology as a research tool in tropical climate. Scars used for erosion dating in cross-sections have been proven as good indicators of geomorphic processes. The relevance of this work is to become the first attempt in tropical regions to date erosion processes using dendrogeomorphological techniques on exposed roots.

Antimicrobial resistance mechanisms and potential synthetic treatments.

Since the discovery of antibiotics by Sir Alexander Fleming they have been used throughout medicine and play a vital role in combating microorganisms. However, with their vast use, development of resistance has become more prevalent and their use is currently under threat. Antibiotic resistance poses a global threat to human and animal health, with many bacterial species having developed some form of resistance and in some cases within a year of first exposure to antimicrobial agents. This review aims to examine some of the mechanisms behind resistance. Additionally, re-engineering organisms, re-sensitizing bacteria to antibiotics and gene-editing techniques such as the clustered regularly interspaced short palindromic repeats-Cas9 system are providing novel approaches to combat bacterial resistance. To that extent, we have reviewed some of these novel and innovative technologies.

Ten-year field study of wood plastic composites in Santiago, Chile: biological, mechanical and physical property performance

Outdoor durability of wood plastic composites is a major focus of research and development efforts toward development of more robust building materials. Exterior exposure of wood plastic composites can result in weathering, moisture absorption, fungal and termite attack to various levels of severity depending on the composite formulation. Long-term (> 6 years) field exposure studies of wood plastic composites are lacking in the scientific literature. It is the overall goal of this paper to report on a ten-year field study of wood plastic composites performed in Santiago, Chile. The wood plastic composite formulations were comprised of polypropylene, wood flour, and various additives. Qualitative measurements were made on the stakes each year including the determination of decay and termite ratings on a scale of 1 to 10 as specified in American Wood Preservers’ Association Standards. Surface weathering or discoloration, surface fungi colonization, presence of mold, and/or lichen was noted. The amount of dimensional change (swelling) of the samples in ground contact was determined. Determination of flexural properties of the control and 10-year exposed wood plastic composite stakes were conducted. All the wood plastic composite stake formulations maintained excellent performance ratings after the 10-year field exposure with ratings of 10 for decay and 10 for termites. The wood plastic composites stakes experienced swelling in contact with the soil with the majority of swelling occurring during the first year of exposure. Although the wood plastic composite stakes did well regarding decay and termite performance, the portion of the stakes exposed above ground exhibited various amounts of weathering, surface fungal colonization, and mold and mildew depending on the formulation. Flexural properties of the wood plastic composite stakes decreased or were maintained for the 10-year exposure depending on the composite formulation.

Modeling of Atmospheric Corrosion in the Tropical Climate of Vietnam

The kinetics of corrosion losses of carbon steel, copper, and zinc in the continental and coastal areas of Vietnam is studied by in situ testing. The dominant climate and aerochemical atmospheric factors are revealed with respect to the metals tested in different periods of their exposure. The mathematical models that characterize the relationship between the time of wetness of metal surface, atmospheric pollution, and corrosion rate are developed. Based on power law model M = At k , the values of constants A and k are calculated for each metal and test site, where parameter A characterizes corrosion losses of metal for the first year of exposure and k denotes the protective properties of a layer of corrosion products.

Species-specific sensitivity of dinoflagellate cysts to aerobic degradation: A five-year natural exposure experiment

Post-depositional sedimentary dinoflagellate cyst associations undergo species-selective degradation under oxic conditions. However, there is little known about the temporal relationship between oxygen concentration and bulk dinocyst degradation rate over the time scale of several years, and if this degradation is mainly microbial or chemical. Whilst the overall sensitivity of heterotrophic dinoflagellate cysts is well documented, sensitivity differences within this group have not been studied. Here we examine the rates of cyst degradation of heterotrophic species over short temporal scales across an anoxic–oxic gradient. Sediment with a known dinoflagellate cyst association largely dominated by heterotrophic dinoflagellates, were connected to trap arrays at two different locations, Cap Blanc (NW Africa) and Gotland Basin (central Baltic Sea) and exposed to four different ambient oxygen concentrations representing a complete oxic gradient from 5.1mL/L to sulphate bearing anoxic waters. Two treatments of either gauze or dialyse membrane in triplicate were established to investigate the effects of chemical or bacterial degradation. Cyst loss was significant at oxic settings, rapidly occurring within the first year of exposure (32%) whereas no significant degradation was observed for suboxic and anoxic exposures. Compiling the degradation rates of individual species under the different exposure settings reveals an overall species sensitivity ranking amongst cysts of heterotrophic species. Species of average resistance: Bitectatodinium spongium, Brigantedinium spp., Echinidinium spp., Echinidinium aculeatum, and Gymnodinium trapeziforme. Species more resistant than average: Stelladinium robustum and Trinovantedinium applanatum. We observe that oxic degradation of cysts of heterotrophic dinoflagellates is fast and selective with maximal cyst association changes during the first year of oxic exposure. These aspects have to be taken into account in palaeoenvironmental and palaeoceanographic reconstructions where bottom/pore water conditions of the upper sediments are oxygenated.

Reconstruction of soil erosion rates from exposed roots in southeast China

ABSTRACTSoutheast China, characterized by a humid subtropical climate, is dominated by dense evergreen broad-leaved forests with the exception for the Changting area, which is one of the most eroded areas in southern China. Various methods have been employed to investigate regional soil erosion dynamics, yet these studies are limited to short periods and few sites. Dendrogeomorphological methods can alleviate this problem due to the long duration of tree rings and easy implementation for many sites. We present the first tree-ring-based soil erosion study in southeastern China, based on 123 exposed roots from 85 Pinus massoniana trees at six sites in Changting. The distinct reduction of cell lumen area of earlywood tracheids of exposed roots is a good bio-indicator for the first year of exposure due to soil erosion for this hot and humid area. The reconstructed soil erosion rates ranged from 4.26 to 43.50 mm/year with an average of 14.14 ± 8.05 mm/year. Soil erosion rate is the highest at the slopes of 10°–30°. This is in line with previous findings using other methods over the study area. In addition, soil erosion in this area is found to be closely related to vegetation types and summer precipitation.

Risk of serious infections, cutaneous bacterial infections, and granulomatous infections in patients with psoriasis treated with anti–tumor necrosis factor agents versus classic therapies: Prospective meta-analysis of Psonet registries

Anti-tumor necrosis factor (TNF) therapy in psoriasis has been associated with an increased risk of serious infections compared with nonbiologic systemic therapies. We sought to quantify the risk of: (1) serious infections (leading to hospitalization, sequelae, or death); and (2) "any infection," bacterial cutaneous infections, and granulomatous infections among patients receiving anti-TNF therapy compared with nonbiologics (acitretin, methotrexate, cyclosporine). We used prospective meta-analysis to combine data from the Psocare registry (Italy), Biobadaderm registry (Spain), and Clalit Health Services database (Israel), including 17,739 patients and 23,357.5 person-years of follow-up. For serious infections, age, gender, and Charlson morbidity index adjusted hazard ratio of exposure to anti-TNFs compared with nonbiologics was 0.98 (95% confidence interval 0.80-1.19), for bacterial cutaneous infections it was 1.00 (95% confidence interval 0.62-1.61), and for granulomatous infections it was 1.23 (95% confidence interval 0.82-1.84). Using methotrexate as comparator and comparing first year of exposure with later exposure did not modify the results. For any infectious episode, risks and relative risks were heterogeneous among registries, probably because of different definitions of outcome. There was lack of power to describe risk of single drugs. In current clinical practice, treatment with anti-TNF drugs was not associated with a higher risk of serious infections than treatment with nonbiologic systemic therapy.

Relationship between the Asbestos Cumulative Exposure Index (ACEI) and the Latency Period of Asbestos Related Diseases (ARD) within an Italian Study Group of Ex-Asbestos Workers

Objectives: The association between asbestos exposure, measured by mean of Asbestos Cumulative Exposure Index (ACEI) and the latency period of non-malignant asbestos-related diseases (ARD) diagnosed according to the American Thoracic Society (ATS) criteria was studied. Methods: 306 exposed asbestos workers in Bari, Italy, were included in a health surveillance program. By means of a standardized questionnaire we assessed asbestos exposure through ACEI. Latency period of Asbestos Related Diseases (ARD) was also assessed. Results: We found a significant inverse correlation between latency and ACEI increasing with ARD severity. ACEI and 30-35 years of age at time of first exposure were inversely associated with the latency period. The risk of ARD increased from baseline to the 2nd follow-up and among subjects exposed for the first time before 1960. Conclusions: The most important factors that caused a reduction in the latency period were the year of first exposure and the ACEI score while smoking habits did not show to play a significant role.

Combining terrestrial laser scanning and root exposure to estimate erosion rates

This paper aims to analyze the reliability of exposed roots oriented perpendicular to the slope to quantify sheet erosion rates based on accurate reconstruction of topography using terrestrial laser scanner (TLS). The study was performed in an experimental sandy badland located in Central Spain. Sampling procedures were conducted in three different homogenous hydrological response units (HRU). We derived eroded soil thickness from by obtaining accurate microtopographic data using TLS. In addition, dendrogeomorphic procedures, based on anatomical changes in root rings, were used to determine the first year of exposure of 46 Pinus pinaster roots. Results indicate that medium-term (±30 year) erosion rates obtained from roots growing perpendicular to the slope were significantly different from those obtained from exposed roots growing parallel to the slope (p-value <0.05). However, at short term (up to 5 years), result agree with those obtained from erosion pin monitoring at the study site, which confirms the potential of reconstructions based on perpendicular roots. The utility of exposed perpendicular roots coupled with accurate eroded soil estimation has been proved. It allows the extension of the applicability of dendrogeomorphic approaches, particularly for ungauged badlands where instrumental data is scarce or completely missing.

A brief review on the atmospheric corrosion of mild steel in Iran

AbstractThis paper presents a review on the atmospheric corrosion of steel, at three sites, in Iran. Corrosion rate values, time of wetness, and the level of pollutants, namely of SO2 and chlorides were determined for the first year of exposure in order to establish the aggressiveness of the atmospheres. The results obeyed well with the empirical kinetics equation of the form C = Ktn.

The role of phonological structure and experience in bilingual children's nonword repetition performance.

The current study examined the influence of phonological structure and language experience on the nonword repetition performance of bilingual children. Twenty-six Spanish-dominant and 26 English-dominant Spanish-English bilingual five-year-old children were matched on current exposure to the dominant language and year of first exposure to English. Participants repeated non-wordlike nonwords in English and Spanish. The Spanish-dominant group performed better than the English-dominant group for both Spanish and English nonwords. In addition, there was a main effect for test language, where Spanish nonwords were produced more accurately than English nonwords overall. The Spanish-dominant group advantage for nonwords is interpreted as emerging from the extra practice the dominant Spanish speakers had producing multisyllabic words.

Assessment of atmospheric dispersion and radiological impact from the Fukushima accident in a 40-km range using a simulation approach

In this study, radiation doses and lifetime attributable health risk to the members of public in a 40-km impact zone around the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) were assessed for the airborne releases that occurred during 11–31 March 2011 from the loss of coolant accident associated with the east Japan earthquake and tsunami event. High-resolution simulations with FLEXPART-WRF Lagrangian particle dispersion model were made using available source term estimates for four significant isotopes (Cs134, Cs137, I131, Xe133). Radiation risk models were adopted to estimate the health risk for leukemia, breast, thyroid, and all solid cancers using simulated distributed lifetime organ doses. The simulations indicate occurrence of hotspots in the spatial activity deposition and radiation dose distribution with high values in the northwest and south-southwest land sectors in a 40-km radius. Large activity depositions (106 to 108 Bq/m2 of Cs137 between 12 and 31 March 2011) and external air doses (10 to 100 μSv/h) are simulated in the above sectors. The simulated air dose rates are found to match with observed doses at 85 % of the monitor stations within a factor of 5. It is estimated that the groundshine and ingestion dose are the principal contributors of the effective dose. Simulated average effective dose during the first year of exposure varied as ~150 mSv in the first few kilometers to 2 mSv at 40 km. The risk incidence was estimated to be high for infants compared to the children and adult age group for all types of cancers. The first 0–20-km range of the FDNPP is characterized with high risk for all types of cancers, for example, 10 to 20 in 10,000 adults for leukemia. The analysis shows that the immediate implementation of countermeasures of evacuation in the 0–20-km zone, sheltering in the 20–40-km zone, and food restrictions by Japan actually reduced significant health risks to the population living near FDNPP. Simulated yearly distribution of total dose indicates that people of evacuated zone can be rehabilitated in about 16 years in the 5–10-km area and 7 years in the 10–20-km area with minimum risk, whereas the near reactor zone of 0–5 km and areas along the plume footprint up to 20 km in the northwest sector of FDNPP require special attention and reclamation measures for rehabilitation. This study demonstrates a total simulation-based approach for estimating the radiation risk for the Fukushima case and helps to assess the time attainment of low risk for inhabitation of the people in the affected areas.

273 The latency period of mesothelioma among a cohort of British asbestos workers (1978–2005)

ObjectivesTo investigate the hypothesis of an inverse relationship between intensity of asbestos exposure and mesothelioma latency among a cohort of asbestos workers in Britain.MethodsThe Great Britain (GB) Asbestos Survey recruited...

Cohort mortality study of garment industry workers exposed to formaldehyde: Update and internal comparisons

To further evaluate the association between formaldehyde and leukemia, we extended follow-up through 2008 for a cohort mortality study of 11,043 US formaldehyde-exposed garment workers. We computed standardized mortality ratios and standardized rate ratios stratified by year of first exposure, exposure duration, and time since first exposure. Associations between exposure duration and rates of leukemia and myeloid leukemia were further examined using Poisson regression models. Compared to the US population, myeloid leukemia mortality was elevated but overall leukemia mortality was not. In internal analyses, overall leukemia mortality increased with increasing exposure duration and this trend was statistically significant. We continue to see limited evidence of an association between formaldehyde and leukemia. However, the extended follow-up did not strengthen previously observed associations. In addition to continued epidemiologic research, we recommend further research to evaluate the biological plausibility of a causal relation between formaldehyde and leukemia.

Application of Picea wilsonii roots to determine erosion rates in eastern Qilian Mountains, Northwest China

As a consequence of global change and human activities, processes of soil erosion are expected to increase in forested areas, resulting in exposed roots. Dendrogeomorphic research was conducted by analyzing exposed roots of Picea wilsonii subjected to continuous denudation along a main road in Tulugou National Forest Reserve, eastern Qilian Mountains, to reconstruct the local soil erosion dynamics. We determined the start of the exposure by examining the shifts in the ring-growth patterns from concentric to eccentric and by analyzing the detailed changes of wood anatomical features of exposed roots. We also find that the width of growth ring, the percentage of latewood and the average cell size of earlywood tracheids are all remarkable signs for soil lowering. According to the analysis of ANOVA (Fisher’s least significant difference method), the reduction of the cell size of earlywood tracheids is verified to be the key indicator for dating the first year of exposure and occurs prior to the other two indicators. Using 40 roots from 23 trees spread along the road, it has been found that erosion rates vary between 3.3 and 13.5 mm/year with an average value about 5.3 ± 2.1 mm/year. The intensity and occurrence of soil erosion may be influenced by the increase of human activities.

Phase IV Vision Study Evaluates Retinal Structure and Function in Adult Patients with Refractory Complex Partial Seizures Treated with Vigabatrin (P07.255)

Objective: To evaluate change in retina structure and function in vigabatrin-naive patients, we initiated a prospective, 1-year open-label trial in patients requiring vigabatrin treatment. Background An important safety issue for vigabatrin is risk of bilateral concentric constriction of visual fields. Design/Methods: ∼80 patients with rCPS for ≥1 year (with ≥2 seizures/month averaged over prior 3 months) will be enrolled at ∼25 US sites. Patients must have failed ≥3 prior therapies for lack of efficacy and must be receiving concomitant AEDs. Vigabatrin-naive patients ≥18 years of age will have visual static perimetry and optical coherence tomography (OCT) assessments at baseline, and 3, 6, 9, and 12 months following vigabatrin initiation. Key endpoints include change from reference value in field width (static perimetry), and change from reference value in retinal nerve fiber layer thickness (OCT and macular thickness OCT). After commencing vigabatrin, patients are assessed every 3 months through automated static perimetry (both standard 30-2 and horizontal meridian full field), OCT, and ancillary exploratory visual endpoints such as visual acuity, color vision, and visual fields by Tangent Corner Test. If deficits are discovered, investigators conduct benefit/risk assessments with patients. Results: By October 2011, 8 sites had been initiated. Screening was initiated for 8 patients. Five were screen failures, and three patients were enrolled. Of these three, two are ongoing study participants, and one was an early termination (seizures returned to baseline rate and patient was discontinued following benefit/risk assessment). One patient had abnormal baseline OCT results (before vigabatrin therapy), emphasizing that patients may have pre-existing afferent visual system conditions. Conclusions: This study is designed to provide a better definition of onset and progression of peripheral visual field defects, to assess the risk of developing vision loss during first year of exposure, and to evaluate OCT for monitoring retinal changes. Supported by: Lundbeck Inc. Disclosure: Dr. Sergott has received personal compensation for activities with Pfizer, Serono, Lundbeck, and Centocor as a speaker and consultant. Dr. Sergott has received personal compensation in an editorial capacity for Current Opinion in Neuro-Opthamology. Dr. Faught has received personal compensation for activities with Pfizer Inc, UCB Pharma, Ortho-McNeil Pharmaceutical, Inc., Valeant Pharmaceuticals, Ovation Pharmaceuticals, Inc., GlaxoSmithKline, Inc., Abbott Laboratories, Inc., and Novartis as a consultant or speaker. Dr. Faught has received research support from Eisai Inc., Marinus, Ortho-McNeil Pharmaceutical, Inc., and Schwarz Biosciences. Dr. Torri has received personal compensation for activities with Lundbeck Research USA as an employee. Dr. Wesche has received personal compensation for activities with Lundbeck Research USA, Inc as an employee.