68 research outputs found

    Applications of SSAFT EOS for determination of the solubilities of solid compounds in supercritical CO2.

    Get PDF
    Using statistical thermodynamics such as Simplified SAFT equation of state (SSAFTEoS) for estimating phase equilibrium and fluid properties of different materials have been used widely. SSAFT EoS has been developed for associative and non-associative compounds. At high pressure inter molecular forces are very important, on the other hand, in spite of the fact that SSAFT EoS has strength theoretical foundation, it can predict the behavior of high pressure systems. In this research, four solid solubility of benzoic acid, naphthalene, pyrene and Phenanthrene in supercritical carbon dioxide have been studied, SSAFT EoS has been used for modeling. At the end the results have been compared with experimental data. The highest and the absolute average deviation error (AAPD), for carbon dioxide - Phenanthrene and benzoic acid - carbon dioxide systems have been reported 2.22 and 4.43 respectively.Keywords: SSAFT EoS; Supercritical carbon dioxide; Solid compounds; Solubility

    Effects of environmental factors on the growth and development of Astacous leptodactylous in Aras River and its Reservoir

    Get PDF
    In order to study plankton population composition and species diversity in different regions of Aras Rivers and the evident reservoir sampling was performed monthly from determined sampling sites from April 2007 to March 2008. Sampling was conducted in Reservoir Lake by a PVC pipe with 2.25 m length and 5 cm diameter by columnar method. Besides, in more dipper (>5 m) sites, sampling conducted from bottom to surface with 1-m intervals (layer sampling) by a 2-liter Ruttner type sampler. In river due to water flow sampling was conducted by a scaled measure. Phytoplankton sampling was performed by 1-liter bottles. Zooplankton was sampled by filtering of 30 L through 55- micron plankton net. These samples were then transferred into bottles and sampling date and the name of station were attached on the bottles. Then, the samples were fixed immediately and transported to laboratory. It should be mentioned some physical parameters were determined in situ. Also, a 1liter and another 2-liter water were collected to determine chlorophyll a and chemical factors respectively. Samples were preserved in dark and cold place for a week. The upper layers (without phytoplankton) were removed and the lower layer (with phytoplankton) was sampled into 5-ml chambers. The enumeration and identification was performed by a Nikon TS100 inverted microscope with ×400 (Phytoplankton) and ×200 (Zooplankton) magnification according to Utermohl (1958) method. About 50 fields were enumerated for each sample. The comparison of physicochemical and biological factors with standard criterion indicated that the presence of a fertile plain, agricultural growth, drought and higher water demand in recent years, as well as, higher population density, the Nakhjavan city location and sewage water flows into the Aras reservoir, the lake is going to be an eutroph lake. Sampling of crayfish was performed from 5 sampling sites seasonally. Aras reservoir freshwater crayfish biomass was sampled in 1391, by putting 100 funnel-shaped nets. At each site one row nets composed of 20 nets were put by rocks, connecting robe and boat. Twenty four hours later, total freshwater cray fish was sampled (at least 300 crayfish was randomly sampled from each site). The samples were transported to laboratory and their sex, sex percentage, biometric characteristics including length, weight were recorded. Length and weight groups were estimated totally and for males and females in each season. The average total length and weight were 106.43 ± 7.94 mm and 35.81 ± 10.86 gr respectively which both are lower than West-Azarbaijan fisheries criterion. In this study only 18.99 percent contained a length higher than exporting level (120 mm). Yet, only 16.46 percent of harvesting had higher than 50 g (exporting level). With regard to data, freshwater shrimp (Astacus leptodactylus) in Aras dam reservoir stock has reduced. In general, male-female ratio was high. The comparison of growth equations confirms that males had higher weights than equal females. In recent years, the freshwater crayfish harvesting has been declined due to increased harvesting and over loading of nutrients into the lake

    Limnological of Bukan Dam Reservoir

    Get PDF
    In order to limnological study of Bukan Dam reservoir, sampling was performed monthly from determined sampling sites from April 2013 to March 2014. Sampling was conducted in reservoir lake by a PVC pipe with 2.25 m length and 5 cm diameter by columnar method. Besides, in more dipper (>5 m) sites, sampling conducted from bottom to surface with 1-m intervals (layer sampling) by a 2-liter Ruttner type sampler. In rivers due to water flow sampling was conducted by a scaled measure. Phytoplankton sampling was performed by 1-liter bottles. Zooplankton was sampled by filtering of 30 L through 55- micron plankton net. These samples were then transferred into bottles and sampling date and the name of station were attached on the bottles. Then, the samples were fixed immediately and transported to laboratory. It should be mentioned some physical parameters were determined in situ. Also, a 2-liter and another 1-liter water were collected to determine chlorophyll a and chemical factors respectively. Samples were preserved in dark and cold place for a week. The upper layers (without phytoplankton) were removed and the lower layer (with phytoplankton) was sampled into 5-ml chambers. The enumeration and identification was performed by a Nikon TS100 inverted microscope with ×400 (Phytoplankton) and ×200 (Zooplankton) magnification according to Utermohl (1958) method. About 50 fields were enumerated for each sample. The comparison of physicochemical and biological factors with standard criterion indicated that the presence of a fertile plain, agricultural growth, drought and higher water demand in recent years, as well as, higher population density, the Saghez city which is the main source of pollution in Bukan dam reservoir has caused that Bukan dam is in the transit state from mesotrophy to eutrophy. The results of the present study suggested that higher trophy in Bukan dam reservoir together with algal high density has negatively affected the Fish life and has reduced the stock in the lake. However, complementary studies should be performed prior to releasing. In this way the problems of other ecosystems should be prevented

    Stock assessment of freshwater crayfish (Astacus leptodactylus) in Aras reservoir

    Get PDF
    360 funnel traps were prepared as 30 in one row. They were bitted and located in different depths in sampling sites. Two rows each composed of 30 traps were located by stone, linking rope and boat with 50 m distance in sampling stations. The results showed that the average of total length of caught crayfish was 106.26±12.89 mm and their mean weight was 38.79 ± 15.54 gr. The largest crayfish had 171 mm length and 216 g weight. Also mean of total CPUE was 9.72±4.49 individuals in the study period. The evaluation by Schnabel approach indicated that fluctuation range of freshwater crayfish biomass with more than 120mm length was 131-313 with an average of 212.59 ±30.23 kilograms per ha. In this study freshwater crayfish biomass with more than 120mm length was 247 × 10^3 kilograms. The Maximum Sustainable Yield (MSY) was estimated 83 × 10^3 kilograms. In this study ّFecundity and biometry of crayfish (Astacus leptodactylus) was investigated during 2012-2013. The results showed that the average of total length of caught crayfish was 106.26±12.89 mm and their mean weight was 38.79 ± 15.54 gr. The largest crayfish had 171 mm length and 216 g weight. Mean number of ovarian and pleopodal eggs were estimated at 286 ± 82 and 246.31 ± 80.41 eggs (with 95% confidence limits), respectively. In this research, male to female ratio was obtained 1.21:1. The time of male moulting at 16°C was started from April and was ended in the late May, when the water temperature reached to 18° C. The second moulting of males and the first moulting of females was performed simultaneously in 18°C water temperature at September. Reproduction of freshwater crayfish was started from November and continued to May of the next year. Harvesting period was from May to late November

    The Effects of Oral Consumption of Selenium Nanoparticles on Chemotactic and Respiratory Burst Activities of Neutrophils in Comparison with Sodium Selenite in Sheep

    Get PDF
    The present study was designed to compare the effects of nano-selenium and of sodium selenite on the chemotactic and respiratory burst activities of neutrophils in sheep. Fifteen sheep were randomly divided into three groups. Groups 1 and 2 received selenium nanoparticles (1 mg/kg) or sodium selenite (1 mg/kg) orally, respectively, for ten consecutive days, and the third group was considered as the control. To determine the chemotactic and respiratory burst activities of the neutrophils, the leading front assay and the NBT test were used on heparinized blood samples that were collected at different intervals (days 0, 10th, 20th, and 30th). The results obtained showed that the chemotactic activities in groups 1 and 2 increased significantly on the 10th, 20th, and 30th day, compared to day 0, and on the 20th day in comparison with the 10th day, while in group 2, there was a significant decrease on the 30th day compared to the 20th day. The chemotactic activities in group 1 were significantly higher than in group 2 on the 10th day and in the control group on the 10th, 20th, and 30th day, but the chemotactic activities in group 2 were significantly higher than those in the control group only on the 20th day. On the 30th day into the experiment, the respiratory bursts in groups 1 and 2 were significantly stronger in comparison with those at day 0. Overall, nano-selenium increased the chemotactic and respiratory burst activities more significantly than sodium selenite, which is suggestive of a stronger stimulatory effect of the Se nanoparticles on intracellular activities

    Diminishing benefits of urban living for children and adolescents’ growth and development

    Get PDF
    Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified

    Repositioning of the global epicentre of non-optimal cholesterol

    Get PDF
    High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol—which is a marker of cardiovascular risk—changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million–4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world

    Global variation in diabetes diagnosis and prevalence based on fasting glucose and hemoglobin A1c

    Get PDF
    Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) are both used to diagnose diabetes, but these measurements can identify different people as having diabetes. We used data from 117 population-based studies and quantified, in different world regions, the prevalence of diagnosed diabetes, and whether those who were previously undiagnosed and detected as having diabetes in survey screening, had elevated FPG, HbA1c or both. We developed prediction equations for estimating the probability that a person without previously diagnosed diabetes, and at a specific level of FPG, had elevated HbA1c, and vice versa. The age-standardized proportion of diabetes that was previously undiagnosed and detected in survey screening ranged from 30% in the high-income western region to 66% in south Asia. Among those with screen-detected diabetes with either test, the age-standardized proportion who had elevated levels of both FPG and HbA1c was 29-39% across regions; the remainder had discordant elevation of FPG or HbA1c. In most low- and middle-income regions, isolated elevated HbA1c was more common than isolated elevated FPG. In these regions, the use of FPG alone may delay diabetes diagnosis and underestimate diabetes prevalence. Our prediction equations help allocate finite resources for measuring HbA1c to reduce the global shortfall in diabetes diagnosis and surveillance

    Repositioning of the global epicentre of non-optimal cholesterol

    Get PDF
    High blood cholesterol is typically considered a feature of wealthy western countries(1,2). However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world(3) and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health(4,5). However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular riskchanged from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.Peer reviewe

    Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

    Get PDF
    Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For schoolaged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median). Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesit
    corecore