1,585 research outputs found
The Removal of Ions by Functionalized Carbon Nanotube: Equilibrium, Isotherms and Thermodynamic Studies
In this studies removal of some ions such as Pb(II), Cd(II) and Cu(II) by single walled carbon nanotubes (SWCNTs) and carboxylate functionalized (SWCNTs-COOH) from aqueous solution were studied. The effect of pH, contact time, initial concentration, ionic strength, temperature, equilibrium, models and thermodynamic parameters on the removal of ions was investigated. The results indicated that Langmuir fits adsorption isotherm data better than Freundlich model. The results also demonstrated that SWCNTs-COOH can remove
ions more effectively. Maximum adsorption capacities for Pb(II), Cu(II) and Cd(II) ions on SWCNTs-COOH were obtained as 96.02, 77.00 and 55.89 mg g–1, respectively and by SWCNTs, as 33.55, 24.29 and 24.07 mg g–1, respectively. Thermodynamic parameters
values showed that the adsorption of ions on SWCNTs-COOH and SWCNTs at 283–313 K are spontaneous and endothermic. Further, adsorption of ions by SWCNTs-COOH and SWCNTs are chemisorption and physisorption processes, respectively
The Removal of Ions by Functionalized Carbon Nanotube: Equilibrium, Isotherms and Thermodynamic Studies
In this studies removal of some ions such as Pb(II), Cd(II) and Cu(II) by single walled carbon nanotubes (SWCNTs) and carboxylate functionalized (SWCNTs-COOH) from aqueous solution were studied. The effect of pH, contact time, initial concentration, ionic strength, temperature, equilibrium, models and thermodynamic parameters on the removal of ions was investigated. The results indicated that Langmuir fits adsorption isotherm data better than Freundlich model. The results also demonstrated that SWCNTs-COOH can remove
ions more effectively. Maximum adsorption capacities for Pb(II), Cu(II) and Cd(II) ions on SWCNTs-COOH were obtained as 96.02, 77.00 and 55.89 mg g–1, respectively and by SWCNTs, as 33.55, 24.29 and 24.07 mg g–1, respectively. Thermodynamic parameters
values showed that the adsorption of ions on SWCNTs-COOH and SWCNTs at 283–313 K are spontaneous and endothermic. Further, adsorption of ions by SWCNTs-COOH and SWCNTs are chemisorption and physisorption processes, respectively
A Comparison of Dysphonia Severity Index in Female Teachers With and Without Voice Complaints in Elementary Schools of Tehran, Iran
Background: Teachers are the greatest group of professional voice users. Prolonged, continuous speaking in a loud voice at school may entail a bad vocal health. It seems that their occupational circumstances make them more likely to develop voice disorders in comparison with other groups.
Objectives: The purposes of this study are 1) to compare teachers with and without voice complaint on the Dysphonia Severity Index and 2) to compare component measures that establish Dysphonia Severity Index.
Materials and Methods: This study included 40 female teachers with voice complaint and 40 female teachers without voice complaint between the ages of 30 and 50 years who were teaching in elementary schools of Tehran city. Simple non-random sampling was done for selected teachers in two groups. The examinees were asked to produce the vowel /a/ three times for calculating any variables, then measures of maximum phonation time, jitter, highest phonational frequency, and lowest intensity were obtained for each subject with Praat and Phonetogram softwares and incorporated into multivariate Dysphonia Severity Index formula. Kolmogoro- Smirnov one sample test and independent sample T-Test was used, the significance level was set at P < 0.05.
Results: Results indicate that female teachers without voice complaint have significantly higher Dysphonia Severity Index scores than female teachers with voice complaint (mean Dysphonia Severity Index: 3.58 vs. 1.05, respectively), also significant differences are observed between groups of with and without complaint for four of components of the DSI (F0 high, I low, jitter and maximum phonation time) (P value = 0.001).
Conclusions: The findings of this study indicate that there is a significant difference in Vocal Quality between teachers with and without voice complaint. This finding may indicate teachers with voice complaint have worse vocal quality that means they are at risk for voice problems. This information may be very important for voice professionals and, speech and language pathology to advice teachers with voice complaint and manage to advocate "good vocal health”
Effect of salinity on nodulation, glutamine synthetase and glutamate synthase activity in nodules of alfalfa (Medicago sativa L.)
Bami cultivar of alfalfa
(Medicago sativa) was inoculated with salttolerant
Sinorhizobium meliloti in solution
culture with different salt concentrations (0,
50, 75 and 100 mmoles l-1NaCl) added
immediately at the time of inoculation. The
results indicated that S. meliloti formed an
infective and effective symbiosis with
alfalfa under saline and nonsaline
conditions. Salinity significantly decreased
shoot and root dry weight, nodule weight
and mean nodule weight. Roots were more
sensitive than shoots, and N2 fixation was
more sensitive to salinity than was plant
growth. Analyses of ammonium
assimilating enzymes in the nodule showed
that glutamine synthetase appeared to be
more tolerant to salinity than glutamate
synthase, and that it limits ammonium
assimilation under saline stress
Effect of different priming methods on germination and seedling establishment of two medicinal plants under salt stress conditions
Priming is one of the seed
enhancement methods that might be resulted
in increasing seed performance (germination
and emergence) under stress conditions,
such as salinity. Salinity is a major
environmental stress which adversely
affects germination and seedling
establishment in a wide variety of crops.
The experiment was arranged as a factorial
in completely randomized design (CRD) at
Seed Research Laboratory of College of
Agriculture, University of Tehran, Iran. The
objective of this research was to evaluate
the effect of different priming methods on
seed germination of two medicinal plants
including lemon balm (Melissa officinalis
L.) and cumin (Cuminum cyminum L.)
under salinity stress. Treatments were
combinations of two levels of salinity stress
(0 and 10 dsm-1) and five levels of priming
(control = non-priming), GA3, manitol,
NaCl and distilled water) with three
replications. Seeds of lemon balm and
cumin were primed for 24 h at 25°C.
Results revealed that different growth traits
(including germination percentage,
germination rate, seedling dry weight,
plumule and radical length) significantly
(p=0.05) decreased with applying salinity.
However, priming of seeds with different
materials particularly GA3 was useful for
alleviating salt stress effects and improving
germination and seedling establishment
under salt stress. Under salinity condition,
primed seeds possessed more germination
and emergence than control. The result of
this experiment is consistent with the
hypothesis that under salinity stress, priming
can prepare a suitable metabolic reaction in
seeds and can improve seed germination
performance and seedling establishment
Phase and amplitude evolution in the network of triadic interactions of the Hasegawa-Wakatani system
The Hasegawa-Wakatani system, commonly used as a toy model of dissipative drift waves in fusion devices, is revisited with considerations of phase and amplitude dynamics of its triadic interactions. It is observed that a single resonant triad can saturate via three way phase locking, where the phase differences between dominant modes converge to constant values as individual phases increase in time. This allows the system to have approximately constant amplitude solutions. Non-resonant triads show similar behavior only when one of its legs is a zonal wave number. However, when an additional triad, which is a reflection of the original one with respect to the y axis is included, the behavior of the resulting triad pair is shown to be more complex. In particular, it is found that triads involving small radial wave numbers (large scale zonal flows) end up transferring their energy to the subdominant mode which keeps growing exponentially, while those involving larger radial wave numbers (small scale zonal flows) tend to find steady chaotic or limit cycle states (or decay to zero). In order to study the dynamics in a connected network of triads, a network formulation is considered, including a pump mode, and a number of zonal and non-zonal subdominant modes as a dynamical system. It was observed that the zonal modes become clearly dominant only when a large number of triads are connected. When the zonal flow becomes dominant as a "collective mean field,"individual interactions between modes become less important, which is consistent with the inhomogeneous wave-kinetic picture. Finally, the results of direct numerical simulation are discussed for the same parameters, and various forms of the order parameter are computed. It is observed that nonlinear phase dynamics results in a flattening of the large scale phase velocity as a function of scale in direct numerical simulations
Opioid use among women on a stable methadone dose
Copyright © 2017, Iranian Journal of Psychiatry and Behavioral Sciences. Background: Opioid use on a stable methadone dose is a health concern in Iran, the most populous Persian Gulf country. However, the underlying reasons associated with opioid use have not been studied. Objectives: The study aimed to explore the reasons associated with opioid use among a group of Persian methadone-maintained women. The other aim was to explore effective interventions to stop this problem. Methods: The current qualitative study was conducted between June 2008 and December 2009. The study sites included ten large methadone treatment clinics in Tehran. The study employed semi-structured interviews with 50 women. Six roundtable meetings were conducted with nine key informants. NVivo 10 was used to thematically analyze the data. Results: Women were on a stable methadone dose of 45 - 115 mg for at least six months. Opioid availability, an opioid-dependent lifestyle, peer pressure and self-treatment were the reasons of opioid use. The provision of cognitive-behavioral therapy, life skills, observational learning, and mental health services were the suggested interventions to stop opioid use. Conclusions: Opioid use on a stable methadone dose had been facilitated by some factors which should be considered in methadone treatment. The suggested interventions should be considered in increasing methadone treatment outcomes
Federated learning for performance prediction in multi-operator environments
Telecom vendors and operators deliver services with strict requirements on performance, over complex and sometimes partly shared network infrastructures. A key enabler for network and service management in such environments is knowledge sharing, and the use of data-driven models for performance prediction, forecasting, and troubleshooting. In this paper, we outline a multi-operator service metrics prediction framework using federated learning that allows privacy-preserved knowledge-sharing across operators for improved model performance, and also reduced requirements on data transfer within an operator network. Federated learning is compared against local and central learning strategies for multi-operator performance prediction, and it is shown to balance the requirements on data privacy, model performance, and the network overhead. Further, the paper provides insights on how data heterogeneity affects model performance, where the conclusion is that standard federated learning has certain robustness to data heterogeneity. Finally, we discuss the challenges related to training a federated learning model with a limited budget on the communication rounds. The evaluation is performed using a set of realistic publicly available data traces, that are adapted specifically for the purpose of studying multi-operator service performance prediction
Effect of green cardamom on lipoproteins, glycemic control and anthropometric parameters: A meta-analysis of randomized clinical trials
Introduction: The aim of this systematic review and meta-analysis was to summarize all the existing randomized controlled trials (RCTs) evidence and to evaluate the effects of green cardamom on lipoproteins, glycemic control and anthropometric parameters in healthy and/or with disease types compared with the control. Method: Two independent authors systematically searched online databases including EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science from inception until 30th July 2019. RCTs complying with the following criteria were included in this meta-analysis: human trials with either cross-over design or parallel design, trials with data on the effects of green cardamom on serum lipoproteins and glycemic control and anthropometric parameters with standard deviation and related 95 confidence interval for the both intervention and placebo groups. The heterogeneity among the included studies was assessed using Cochrane's Q test and I-square (I2) statistic. Data were pooled using a random-effects model and weighted mean difference (WMD) was considered as the overall effect size. Result: Seven trials were included in this meta-analysis. Triglycerides were significantly reduced after cardamom supplementation when compared with the control group. Cardamom intake from 3 small studies resulted in a significant increase in BMI when compared with the control group. However, cardamom supplementation did not have any significant effect on total cholesterol, LDL-cholesterol, HDL-cholesterol, fasting plasma glucose and body weight when compared with the control group. Conclusion: This meta-analysis demonstrated that green cardamom intake significantly reduced triglycerides levels which may have played an indirect role in improved clinical symptoms in diseases with metabolic disorders. © 2020 European Society for Clinical Nutrition and Metabolis
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