2,039 research outputs found
Mathematical Modeling of the Effect of Meanders Removal on Changes in Erosion Rate: A Case Study in Karun River's Gangieh Meander
One of the nonstructural methods of increasing aqueduct and decreasing flood balance in rivers is to create a shortcut to remove steeped arches. With regard to the dynamic system of river, any type of change in the stable structure of the river may lead to possible changes in the river morphology and creates new problems. In this study, after removing Ganjieh meander in downstream Ahvaz with the aim of organizing and increasing Karun River's aqueduct around Ahvaz city, hydraulic changes of flow and erosion and sediment level after removing meander were modeled using Hec-Ras4 mathematic model. This model was conducted in Karun River in an interval of 16 kilometers around Zargan – Farsiat for 25 years. Results of this research showed that, in the first 16 kilometers, in low to medium discharges of Karun in upstream meander, the water surface balance was high and decreases over time and in high water, discharge does not change significantly over time. In downstream meanders, in medium to high water, discharges, after removing meander water level balance increase compared to conditions before remove. Overall, before and after removing meander, in 16 to 18 kilometer as well as 35 to 40 kilometers, the cumulative weight of erosion and or sedimentation has the maximum value and their density increases over time
Mathematical Modeling of the Effect of Meanders Removal on Changes in Erosion Rate: A Case Study in Karun River's Gangieh Meander
One of the nonstructural methods of increasing aqueduct and decreasing flood balance in rivers is to create a shortcut to remove steeped arches. With regard to the dynamic system of river, any type of change in the stable structure of the river may lead to possible changes in the river morphology and creates new problems. In this study, after removing Ganjieh meander in downstream Ahvaz with the aim of organizing and increasing Karun River's aqueduct around Ahvaz city, hydraulic changes of flow and erosion and sediment level after removing meander were modeled using Hec-Ras4 mathematic model. This model was conducted in Karun River in an interval of 16 kilometers around Zargan – Farsiat for 25 years. Results of this research showed that, in the first 16 kilometers, in low to medium discharges of Karun in upstream meander, the water surface balance was high and decreases over time and in high water, discharge does not change significantly over time. In downstream meanders, in medium to high water, discharges, after removing meander water level balance increase compared to conditions before remove. Overall, before and after removing meander, in 16 to 18 kilometer as well as 35 to 40 kilometers, the cumulative weight of erosion and or sedimentation has the maximum value and their density increases over time
Annotating Privacy Policies in the Sharing Economy
Applications (apps) of the Digital Sharing Economy (DSE), such as Uber,
Airbnb, and TaskRabbit, have become a main enabler of economic growth and
shared prosperity in modern-day societies. However, the complex exchange of
goods, services, and data that takes place over these apps frequently puts
their end-users' privacy at risk. Privacy policies of DSE apps are provided to
disclose how private user data is being collected and handled. However, in
reality, such policies are verbose and difficult to understand, leaving DSE
users vulnerable to privacy intrusive practices. To address these concerns, in
this paper, we propose an automated approach for annotating privacy policies in
the DSE market. Our approach identifies data collection claims in these
policies and maps them to the quality features of their apps. Visual and
textual annotations are then used to further explain and justify these claims.
The proposed approach is evaluated with 18 DSE app users. The results show that
annotating privacy policies can significantly enhance their comprehensibility
to the average DSE user. Our findings are intended to help DSE app developers
to draft more comprehensible privacy policies as well as help their end-users
to make more informed decisions in one of the fastest growing software
ecosystems in the world
An Evaluation of the Influence of Royal Jelly on Differentiation of Stem Cells into Neuronal Cells Invitro
ABSTRACT
BACKGROUND AND OBJECTIVE: P19 carcinoma stem cells are able to differentiate into embryonic cells with
three germ layers. Given the fact that differentiated cells can reduce complications associated with degenerative
diseases of the nervous system, in this study, we aimed to investigate the differentiation of P19 stem cells into neuronal
cells under the influence of royal jelly.
METHODS: In this basic-applied research, embryoid bodies, prepared in P19 cell suspension culture, were transferred
to gelatinized containers and classified in six groups, receiving 25, 50, 100, 150, 200, and 300 mg/ml of royal jelly,
respectively; five wells were allocated to each group of cells. Morphological evaluation of cell differentiation was
performed via cresyl violet staining. Also, immunofluorescence technique was used to track the expression of neuronal
marker proteins such as synaptophysin and β-tubulin III. Finally, the findings were analyzed.
FINDINGS: The present findings showed that cells exposed to royal jelly responded positively to specific staining of
nerve cells. In groups receiving different concentrations of royal jelly, the mean percentage of cell differentiation was
significantly higher than the negative control group (9±2.3). The highest percentage of cell differentiation was observed
in groups treated with 200 and 300 mg/ml of royal jelly, respectively (98±4.8 and 99.3±2.2, respectively) (p<0.05).
Based on the findings, the mean percentage of cell differentiation in the group receiving 200 mg/ml of royal jelly was
not significantly different from the group receiving a concentration of 300 mg/ml.
CONCLUSION: The results of the present study showed that P19 cells are able to differentiate into neuronal cells, and
therefore, they could be used in cell-based therapy for neurological disease
A Novel Protocol for Stevia Rebaudiana (Bert.) Regeneration
Stevia rebaudiana Bertoni has sweet substances (stevioside) in its leaves that are free of calories and their consumption is beneficial for diabetic patients and is also helpful in high blood pressure also. Because of low capability in seed germination, tissue culture is an appropriate method for propagation of this plant. In the current study, optimization of stevia in vitro cultivation via direct organogenesis with different explants, light intensities and plant hormones has been examined. These treatments included BAP (at 0.5, 1, 1.5 and 2mg/l) in combination with 2,4-D, IBA and NAA (each with concentrations of 0.1, 0.2 and 0.5mg/l) and different light intensities (Dark, 2000, 4000 and 6000 lux). MS was utilized as a basal medium. Results indicated the highest rate of organogenesis (85%) occurred on the axillary buds explants with a medium containing 1.5mg/l BAP + 0.1mg/l NAA under 6000 lux light intensity. Also, the highest range of primary organ per explant (42) with 0.3cm length was achieved at this condition. The most efficient medium for rhizogenesis i.e. 100% root production along with the highest root number (11 with approximately 7.13cm length) was obtained in presence of activated charcoal and 1mg/l of IBA. At the end of rhizogenesis experiments, the plantlet length and node multiplicity were 12.8cm and 7 respectively. Greenhouse cultivation of these plantlets was successful
Significance of physicochemical factors in the transmission of Escherichia coli and chloride
Background: Organic manures are the source of many pathogenic bacteria which could be dangerous
for human health. Bacterial transmission and retention in soil is important for processes ranging
from contaminant degradation during in situ bioremediation to transport of pathogenic bacteria into
groundwater.
Methods: The aim of this study was to evaluate the transport of Escherichia coli and chloride (Cl) in the
soil saturation conditions, considering the importance of preferential flow using synthetic macrospores
(different diameters of macrospores including 0, 1 and 2 cm) and HYDRUS-2D model. Also, the
effect of different salinity levels of water (including electrical conductivity of 1, 2 and 4 dSm-1) on the
transmission of E. coli was investigated. The preferential flow system was prepared and designed using
two sand sizes including fine sand and coarse sands in the columns.
Results: The results showed that the retention of E. coli increased with the ionic strength of the solution,
while the effect of E. coli in the fine sand was greater than that of the coarse sand. This bacterial transfer
behavior was well described by numerical simulations. The importance of preferential flow in bacterial
transfer showed that it increases at higher ionic strength, even if overall transmission is reduced.
Although the bacterial transmission is facilitated in salinity, the results of this study showed that with
increase of ionic strength of the soil solution, the amount of bacterial purification was increased that
could be effective in controlling groundwater contamination with saline water management.
Conclusion: According to the results, with increase of ionic strength of the soil solution, the amount of
bacterial purification was increased that could be effective in controlling groundwater contamination
with saline water management, so that the least transition has taken place and the conditions for the
use of unconventional water sources were also created, without the environmental problem of the risk
of groundwater pollution.
Keywords: Escherichia coli, Soil, Water pollutio
Effect of intraradicular reinforcement strategies on the fracture strength of endodontically treated anterior teeth with overflared canals
This study is done to evaluate the effect of different reinforcement techniques of overflared root canals with fiber posts on the fracture resistance of endodontically treated anterior teeth. It also introduces a new technique for simultane
Removal of Pb(II) from Aqueous Solutions Using Magnetic Mesoporous Silica Nanocomposites: Modeling and Optimization Based on Response Surface Methodology
In the adsorption process of heavy metals, a major challenge is to design and develop adsorbent materials in an abundance of accessible adsorption sites with high affinity to achieve both fast adsorption kinetics and increased adsorption capacity for toxic contaminants. The removal of pollutants by mesoporous silica adsorbents is now in the limelight due to the nontoxicity and biocompatibility of these materials with the environment. In this study, a fibrous core-shell magnetic mesoporous composite (Fe3O4/SiO2/KCC-1) was successfully synthesized and used as a nano-adsorbent to remove Pb(II) from an aqueous solution. The adsorbent was characterized by employing TEM, SEM, FTIR, VSM, XRD, and N2 adsorption–desorption techniques. According to the results, Fe3O4/SiO2/KCC-1 was successfully synthesized with an average pore diameter of 7.94 nm, a surface area of 813.07 m2 g-1, and a pore volume of 1.41 cm3 g-1. The response surface methodology (RSM) was then adopted in the central composite design (CCD) to optimize parameters of the adsorption process. The optimal conditions for Pb(II) adsorption were then determined at a temperature of 80 °C, an adsorption dosage of 0.04 g L-1, a pH 5.6, and the contact time of 38 min. The removal rate of Pb(II) was 90%. Studies of equilibrium and kinetics indicated that the adsorption process followed Langmuir’s isotherm and the pseudo-first-order model with correlation coefficients of 0.98 and 0.99, respectively. The maximum adsorption capacity of Fe3O4/SiO2/KCC-1 was reported 574.4 mg g-1. Moreover, the thermodynamic parameters known as enthalpy (ΔH° = +5.84 kJ mol-1), negative Gibbs free energy (∆G°) values, and entropy (ΔS° = +23.42 kJ mol-1 K-1) indicated that the adsorption was endothermic and spontaneous with the increased disorder at the solid–liquid interphase
Hydrology and hydrobiological study of the Iranian waters in the Oman Sea
In this survey, hydrology and hydrobiologycal studies in the northern part of the Oman Sea and Strait of Hormuz within the Iranian waters were conducted during 2007 and 2009.The project was implemented using Ferdous research vessel.The sampling area included the whole stretch of the Iranian waters along the northern part of the Oman Sea from the northeast of the Iranian marine border of 30 miles Bay of Chabahar to the mouth of the Hormuz Strait in Hormuzgan province. Along this stretch 10 equally distributed transects at a distance of 30 miles away from each other were designated, 4 main sampling stations at a distance of 10 miles from one another were fixed at each transect. Sampling was conducted twice a year (spring and autumn 2007 and 2009). According to achieved results; we can point out to the following outlines below: permanent thermocline exists annually in this body of water; where only the point of start, and the fracture width of thermocline layer; alter with alteration of seasons. Horizontal and vertical distribution of electrical conductivities, obey exactly from thermal degree structure.Level of salinity increase from east to west, but it decrease; from surface to deeper layers. In deeper regions, especially in the midway east of the Oman Sea; the level of salinity in the deeper waters from 150-300m, there is a considerable increase observed in salinity, due to very high salinity waters of The Persian Gulf; that are entering the Sea of Oman, via the Striate of Hormouz from the bottom; where they are having their effect following the whole length of the Sea of Oman; through their path. The level of water density from offshore to onshore, and from surface to deeper levels increase in such a way that. The level of Chlorophyll-a in surface waters, in the northeastern midway; is higher than the northwestern midway of the Sea of Oman, and it decreases from inshore to offshore waters, but its vertical distribution; has caused somehow in a way, that the highest distribution and concentration of chlorophyll-a; to be formed in deeper layers, between about 10-40m depths. Then by the increase in water depth, its concentration decreases drastically; reaching zero in magnitude. Concentration of dissolved oxygen is higher in spring in comparison to that of autumn, and the highest level is achieved in water layers located at 10-40m depth (where the level of chlorophyll-a is higher). In addition to which, that its vertical structure; shows the existence of a permanent oxycline layer at this region, in a way that; by seasonal alterations (similar to that of thermocline layer), only the point of start and that of the thickness of oxycline layer changes.pH level decreased from water surface, and its vertical alteration trend; obeyed to that of the same for temperature and chlorophyll-a vertical structure, especially for dissolved oxygen parameter, where the maximum decrease was recorded coinciding with formation of oxycline layer.Nutrient levels increased; at surface water layers from offshore to inshore, and from west to east, for the same body of water. In addition to that, concentration of nutrients in autumn (after monsoon); were more than that of, spring season (before monsoon), where; concentration of their vertical structure increase from water surface toward deeper sections. In this survey six phylum of phytoplankton including in Bacillariophyta (88) Pyrophyta (111), Cyanophyta (6), Chropmophyta (2), Euglenaphyta and silicoflagellate (1) were identified. A result showed that density decreased in most transects from inshore toward sea and maximum density was in photic layer (0-25m). Phytoplankton densities (without Cochlodinium density) in post-monsoon were recorded higher than pre-monsoon, furthermore phytoplankton density in 2009 was more than 2007(6073±1038) Species richness was indexed in the pre-monsoon and post-monsoon 2007 (0.337-0.519), (0.296-0.396) respectively and to (0.967-1.525), (1.407-1.531) for 2009. Zooplankton population in this study is characterized by eight phyla, eight classes, 15 orders, 35 families and 78 genus. In 2007, the pre-monsoon percentage of groups were frequently as following: Copepoda with stages of Nauplius and Copepeditide were 78%, Ciliphora 8%, Sarcomastigophora 4% and Hemichordata 6%. In post-monsoon order of frequency Copepoda 80%, Ciliophora 6%, Coelenterata 5%. Copepoda was the most abundant group of zooplankton.In 2009, The pre-monsoon Copepoda (82%), Cilillophora(9%), Sacromastigophora(4%) and Hemichordata (2%) in post-monsoon Copepoda(70%), Ciliophora (20%),Sarcomastigophora(4%) and Hemichordat (2%) dominante group were respectively. The static result showed significance betweendifferent transects and layers.We were recorded 31 ichthyoplankton families with different density and distribution during 2 years. Among benthic invertebrate polychaete with average 800 ind-2 and then amphipods and gastropods were the most abundance.Yearly density of macrobenthos showed polychaete with the average of 500 ind.-2 in 2007 and 1000 ind.-2 in 2009 was the most abundance . Macrobenthos density in postmonsoon was more than premonsoon.p0.05.There was a negative regression between macrobentos density and depth(p<0.05) and positive rsgresion between macrobenthos and oxygen concentration and temperature.(p<0.05).There was also a significant relationship between macrobenthos ,coppepda and polychaete density with organic carbon.p<0.05.Bimass changed from strait to Golf and coast to depth increasingly.p<0.05. The results of the measurement of heavy metals in water and Sea bed showed that the Concentration of heavy metals in surface layers in waters of the northern half of Oman Sea and Strait of Hormuz in spring (pre-monsoon) is more than autumn (after monsoon), and Degree of pollution in these areas are low compared to the global scale, Also, The results of the degree of contamination of sediments across the northern half of Oman Sea and comparison Global indicators of environmental quality assessment, it was found that the degree of contamination in the area in spring and autumn are low pollution. Comparison of the TPAH concentration of in Iranian waters of the Gulf of Oman, with other parts of the world indicate that degree of pollution of the waters in the spring 86 in the other seasons too low to medium level is low; but the degree of contamination in sediments, both in spring and in the autumn is much less; It means that the current risk on behalf of these contaminants, does not threaten the fish and benthos. The results of the risk assessment (THQ) of heavy metals in consumer, for yields Sangsar fish and fish Gish showed that the risk for both all the heavy metals, significantly lower than the one(1<) and This means that urban communities in the province does not present any danger of feeling threatened
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