89 research outputs found
Correction to: Indoor and outdoor concentrations of BTEX and formaldehyde in Tehran, Iran: effects of building characteristics and health risk assessment (Environmental Science and Pollution Research, (2018), 10.1007/s11356-018-2794-4)
The original publication of this paper contains a mistake. The correct name and affiliation of the 3rd Author is presented in this paper. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature
Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing
No abstract available
A systematic review and meta-analysis of human biomonitoring studies on exposure to environmental pollutants in Iran
Population exposure to environmental contaminants can be precisely observed through human biomonitoring studies. The present study aimed to systematically review all the biomonitoring studies conducted in Iran on some selected carcinogen environmental pollutants. In this systematic review study, 11 carcinogen agents were selected including arsenic, cadmium, chromium, nickel, lindane, benzene, trichloroethylene (TCE), pentachlorophenol (PCP), radon-222, radium-224, � 226, � 228, and tobacco smoke. The Web of Science, PubMed, and Scopus databases were searched for peer-reviewed articles published in English. After several screening steps, data were extracted from the studies. Meta-analyses (a random-effect model using the DerSimonian-Laired method) were performed only for the biomarkers with more than three eligible articles, including cadmium in blood and breast milk, and arsenic in breast milk. Methodological quality of the studies was assessed using the Newcastle-Ottawa Quality Assessment Scale adapted for cross-sectional studies. Of the 610 articles found in the database search, 30 studies were eligible for qualitative review, and 13 were included in the meta-analysis (cadmium in blood (n = 3), cadmium in breast milk (n = 6), and arsenic in breast milk (n = 4)). The overall pooled average concentrations (95 CI) of cadmium in blood, cadmium in breast milk, and arsenic in breast milk were 0.11 (95 CI: 0.08, 0.14), 5.38 (95 CI: 3.60, 6.96), and 1.42 (95 CI: 1.02, 1.81) µg/L, respectively. These values were compared with the biomarker concentrations in other countries and health-based guideline values. This study showed that there is a need for comprehensive action plans to reduce the exposure of general population to these environmental contaminants. © 202
Changing expression of vertebrate immunity genes in an anthropogenic environment: a controlled experiment
Background: The effect of anthropogenic environments on the function of the vertebrate immune system is a problem of general importance. For example, it relates to the increasing rates of immunologically-based disease in modern human populations and to the desirability of identifying optimal immune function in domesticated animals. Despite this importance, our present understanding is compromised by a deficit of experimental studies that make adequately matched comparisons between wild and captive vertebrates.
Results: We transferred post-larval fishes (three-spined sticklebacks), collected in the wild, to an anthropogenic (captive) environment. We then monitored, over 11 months, how the systemic expression of immunity genes changed in comparison to cohort-matched wild individuals in the
originator population (total n = 299). We found that a range of innate (lyz, defbl2, il1r-like, tbk1)and adaptive (cd8a, igmh) immunity genes were up-regulated in captivity, accompanied by an increase in expression of the antioxidant enzyme, gpx4a. For some genes previously known to show seasonality in the wild, this appeared to be reduced in captive fishes. Captive fishes tended to express immunity genes, including igzh, foxp3b, lyz, defbl2, and il1r-like, more variably. Furthermore, although gene co-expression patterns (analyzed through gene-by-gene correlations and mutual information theory based networks) shared common structure in wild and captive fishes, there was also significant divergence. For one gene in particular, defbl2,
high expression was associated with adverse health outcomes in captive fishes.
Conclusion: Taken together, these results demonstrate widespread regulatory changes in the immune system in captive populations, and that the expression of immunity genes is more constrained in the wild. An increase in constitutive systemic immune activity, such as we
observed here, may alter the risk of immunopathology and contribute to variance in health in vertebrate populations exposed to anthropogenic environments
Burden of disease scenarios for 204 countries and territories, 2022–2050: a forecasting analysis for the Global Burden of Disease Study 2021
Background: Future trends in disease burden and drivers of health are of great interest to policy makers and the public at large. This information can be used for policy and long-term health investment, planning, and prioritisation. We have expanded and improved upon previous forecasts produced as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) and provide a reference forecast (the most likely future), and alternative scenarios assessing disease burden trajectories if selected sets of risk factors were eliminated from current levels by 2050. Methods: Using forecasts of major drivers of health such as the Socio-demographic Index (SDI; a composite measure of lag-distributed income per capita, mean years of education, and total fertility under 25 years of age) and the full set of risk factor exposures captured by GBD, we provide cause-specific forecasts of mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) by age and sex from 2022 to 2050 for 204 countries and territories, 21 GBD regions, seven super-regions, and the world. All analyses were done at the cause-specific level so that only risk factors deemed causal by the GBD comparative risk assessment influenced future trajectories of mortality for each disease. Cause-specific mortality was modelled using mixed-effects models with SDI and time as the main covariates, and the combined impact of causal risk factors as an offset in the model. At the all-cause mortality level, we captured unexplained variation by modelling residuals with an autoregressive integrated moving average model with drift attenuation. These all-cause forecasts constrained the cause-specific forecasts at successively deeper levels of the GBD cause hierarchy using cascading mortality models, thus ensuring a robust estimate of cause-specific mortality. For non-fatal measures (eg, low back pain), incidence and prevalence were forecasted from mixed-effects models with SDI as the main covariate, and YLDs were computed from the resulting prevalence forecasts and average disability weights from GBD. Alternative future scenarios were constructed by replacing appropriate reference trajectories for risk factors with hypothetical trajectories of gradual elimination of risk factor exposure from current levels to 2050. The scenarios were constructed from various sets of risk factors: environmental risks (Safer Environment scenario), risks associated with communicable, maternal, neonatal, and nutritional diseases (CMNNs; Improved Childhood Nutrition and Vaccination scenario), risks associated with major non-communicable diseases (NCDs; Improved Behavioural and Metabolic Risks scenario), and the combined effects of these three scenarios. Using the Shared Socioeconomic Pathways climate scenarios SSP2-4.5 as reference and SSP1-1.9 as an optimistic alternative in the Safer Environment scenario, we accounted for climate change impact on health by using the most recent Intergovernmental Panel on Climate Change temperature forecasts and published trajectories of ambient air pollution for the same two scenarios. Life expectancy and healthy life expectancy were computed using standard methods. The forecasting framework includes computing the age-sex-specific future population for each location and separately for each scenario. 95% uncertainty intervals (UIs) for each individual future estimate were derived from the 2·5th and 97·5th percentiles of distributions generated from propagating 500 draws through the multistage computational pipeline. Findings: In the reference scenario forecast, global and super-regional life expectancy increased from 2022 to 2050, but improvement was at a slower pace than in the three decades preceding the COVID-19 pandemic (beginning in 2020). Gains in future life expectancy were forecasted to be greatest in super-regions with comparatively low life expectancies (such as sub-Saharan Africa) compared with super-regions with higher life expectancies (such as the high-income super-region), leading to a trend towards convergence in life expectancy across locations between now and 2050. At the super-region level, forecasted healthy life expectancy patterns were similar to those of life expectancies. Forecasts for the reference scenario found that health will improve in the coming decades, with all-cause age-standardised DALY rates decreasing in every GBD super-region. The total DALY burden measured in counts, however, will increase in every super-region, largely a function of population ageing and growth. We also forecasted that both DALY counts and age-standardised DALY rates will continue to shift from CMNNs to NCDs, with the most pronounced shifts occurring in sub-Saharan Africa (60·1% [95% UI 56·8–63·1] of DALYs were from CMNNs in 2022 compared with 35·8% [31·0–45·0] in 2050) and south Asia (31·7% [29·2–34·1] to 15·5% [13·7–17·5]). This shift is reflected in the leading global causes of DALYs, with the top four causes in 2050 being ischaemic heart disease, stroke, diabetes, and chronic obstructive pulmonary disease, compared with 2022, with ischaemic heart disease, neonatal disorders, stroke, and lower respiratory infections at the top. The global proportion of DALYs due to YLDs likewise increased from 33·8% (27·4–40·3) to 41·1% (33·9–48·1) from 2022 to 2050, demonstrating an important shift in overall disease burden towards morbidity and away from premature death. The largest shift of this kind was forecasted for sub-Saharan Africa, from 20·1% (15·6–25·3) of DALYs due to YLDs in 2022 to 35·6% (26·5–43·0) in 2050. In the assessment of alternative future scenarios, the combined effects of the scenarios (Safer Environment, Improved Childhood Nutrition and Vaccination, and Improved Behavioural and Metabolic Risks scenarios) demonstrated an important decrease in the global burden of DALYs in 2050 of 15·4% (13·5–17·5) compared with the reference scenario, with decreases across super-regions ranging from 10·4% (9·7–11·3) in the high-income super-region to 23·9% (20·7–27·3) in north Africa and the Middle East. The Safer Environment scenario had its largest decrease in sub-Saharan Africa (5·2% [3·5–6·8]), the Improved Behavioural and Metabolic Risks scenario in north Africa and the Middle East (23·2% [20·2–26·5]), and the Improved Nutrition and Vaccination scenario in sub-Saharan Africa (2·0% [–0·6 to 3·6]). Interpretation: Globally, life expectancy and age-standardised disease burden were forecasted to improve between 2022 and 2050, with the majority of the burden continuing to shift from CMNNs to NCDs. That said, continued progress on reducing the CMNN disease burden will be dependent on maintaining investment in and policy emphasis on CMNN disease prevention and treatment. Mostly due to growth and ageing of populations, the number of deaths and DALYs due to all causes combined will generally increase. By constructing alternative future scenarios wherein certain risk exposures are eliminated by 2050, we have shown that opportunities exist to substantially improve health outcomes in the future through concerted efforts to prevent exposure to well established risk factors and to expand access to key health interventions
Effects of Ramadan fasting on cardiovascular risk factors: a prospective observational study
Organic modification of montmorillonite for application in plasticized PVC nanocomposites
A new type of organic compound for modifying clay minerals suitable for use in plasticized polyvinyl chloride was selected and studied. The theory of Hansen solubility parameters was used to predict the miscibility between potential organomodifiers and polyvinyl chloride. In a series of systematic experiments using four very different solvents (i.e., water, ethanol, tetrahydrofuran and chloroform) and three different types of Mt (i.e., Mt-Na + , Mt-PGV and Mt-Ca ++ ), the importance of various parameters to the process of clay mineral intercalation was investigated. The effects of each combination were evaluated employing wide-angle X-ray diffraction and thermogravimetry. The results of swelling experiments on clay mineral in various solvents correlated well with the results of a theoretical preliminary study using Hansen solubility parameters. The extent of swelling followed the order H 2 O > EtOH > THF > chloroform. The d-spacing seemed to be little affected by the type of solvent used in the modification, while the type of Mt used was important to the intercalation results. Organomodification of Mt-Na + increased the d-spacing by nearly 0.7nm when tributyl citrate was used as a chelating agent. Similar modification of Mt-Ca ++ showed an increase of 0.3nm only. Furthermore, thermogravimetry and DTG curves showed significant structural differences between Mt-Na + and Mt-Ca ++
Study of Scour and Flow Patterns around Triangular-Shaped Spur Dikes
River bank erosion can upset the balance of the river and its aquatic habitat, as well as the lands and facilities adjacent to the river. As hydraulic structures, spur dikes are constructed perpendicularly to erodible river banks in an attempt to divert the flow toward the middle of the channel as a measure for reducing and controlling river bank erosion. The expansion of the scour hole at the tip of the spur dike can lead to structure failure. Inclining the horizontal crest of the rectangular spur dikes (called triangular-shaped spur dike) can reduce the scouring at their tips. There are limitations on the design criteria for this newly-introduced structure. In the present study, the scour patterns developed around triangular spur dikes were examined under different hydraulic conditions and compared these patterns with those obtained for common type of spur dikes (rectangular spur dikes). The three-dimensional velocity components around triangular and rectangular spur dikes were also measured. According to the results, maximum scour hole depth and volume were smaller in the triangular spur dikes than in their rectangular counterparts. Quantitatively, on average, maximum scour hole depth and volume in the former were, respectively, 44% and 70% less than those in the latter. Based on the analyzed the flow patterns, it is recommended that the spacing between the triangular spur dikes should not exceed 5.5 times the effective length of the structure
Fixed precision Sequential Sampling of Aphids on Wheat fields in Ahvaz
Introduction: Aphids are secondary pests in cereal fields but sometimes they outbreak and cause considerable damage to wheat and barley. Integrated pest management is one of the most important strategy in insect ecology and estimating population can be used to employ the strategy. Sampling of population is the most basic outdoor activities in ecology and as time goes need to fast and reliable sampling methods be felt more. Dispersion can be quantified by the comparison of observed frequency distribution data (based on a common sample unit) with mathematical models used to describe possible spatial distributions. Knowledge about dispersion pattern of an organism is required for understanding population biology, resource exploitation and dynamics of biological control agents. Moreover determination the dispersion pattern of a species is essential for developing an effective pest management program. . The degree of aggregation can be expressed by several indices of dispersion. Taylor's power law and Iwao's patchiness regression are two main models that also depend on the relationship between the sample mean and the variance of insect numbers per sampling unit. The slope of the regression model is used as an index of aggregation. Usually, sampling of insects is from the estimatation of some population parameter for research purposes or to make a pest control decision. However, the often large, fixed sample size necessary for research may be inappropriate where frequent and rapid monitoring is required to make a control decision. In such cases the sequential sampling method may be a better alternative as it characteristically has a variable sample number and can serve to classify a population in relation to a treatment level rather than provide actual estimates of population density. Designing sampling plans based on these indicators has been reported to reduce sampling effort, cost and minimize variation of sampling precision. As there were no any information about the spatial distribution and sequential sampling program of cereal aphids in Khuzestan province, this study was undertaken to determine dispersion pattern of cereal aphids in order to develop a suitable sampling plan for these pests.
Material and Methods: In order to assess the distribution pattern and density of aphid species on wheat the mixed population of aphids was sampled during 2012-2013 at three pesticide-free wheat fields (two wheat fields in Ahvaz and one in Mollasani) in Khuzestan province, southwestern of Iran. Each field was sampled twice a week throughout the growing season from initiation of tillering to grain ripening stage. Each sample included 25 plant, which were chosen randomly and the number of aphids was counted. Tillers were collected by traveling an X-shaped procedure. Spatial distribution of different developmental stages of wheat aphids were described by calculating dispersion indices (Taylor’s and Iwao’s indices of dispersion). A sequential sampling plan was also developed using the fixed precision method of Green for estimating the density of adults, Nymphs and total population.
Result and Discussion: Analysis of spatial distribution pattern using Taylor’s power law and Iwao’s regression model showed that Taylor's power law provides a better description of the aphids spatial distribution and based on this model dispersion pattern of wheat aphids population was aggregated for nymph and the total of life stage, but was random for adult life stage. Green’s fixed precision sequential sampling plan at precision levels of 0.25 and 0.10 was designed for estimating the density of the adult, nymph and total population. The results showed that the required sample size increased dramatically with increasing levels of precision, and generally ranged from 1 to 34 and 8 to 210 tillers at the precision levels of 0.25 and 0.10 respectively, and the optimum sample size for the estimation of mean aphid density decreased approximately between 44% - 83%
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