mehdi shahraki

Adsorption of some nitrophenols as significant environmental pollutants was investigated on pristine graphene and functionalized graphene sheets with O–H···F groups via quantum mechanical calculations, molecular dynamics, and Monte Carlo simulations. Energy data, structural parameters, electronic properties, electron charge densities, molecular electrostatic potential maps, charge transfer, density of states plots, non-covalent interactions, and adsorption isotherms were surveyed to get the possibilities of the selected adsorbents for the adsorption of nitrophenols. Molecular dynamics simulations disclosed that the hydrogen bonding and van der Waals interactions effectively assist to stability of the adsorbate-adsorbent pairs. Average binding energy of the pairs includes nitrophenols in closed and open form with adsorbents is 21.45 and 38.19 kcal mol-1, respectively. Also, sum of electron charge density values at bond critical points that formed between nitrophenols in closed and open form with adsorbents is 42.03 and 43.54 au, respectively. The aromaticity of the central rings of the graphene and functionalized graphene is 0.0487 and 0.0482 au, respectively. Decrease of aromaticity at central rings of both adsorbates and adsorbents is followed by increase of binding energy values of the pairs. Energy decomposition analysis indicate that average electrostatic energy of the pairs include nitrophenols in closed and open form with adsorbents is -14.08 and -14.32 kcal mol-1, respectively. Results suggested that the pristine graphene and functionalized graphene would be suitable adsorbents for adsorption of nitrophenols.

Chlorofluorocarbons (CFCs) are among the environmental pollutants that destroy the ozone layer, and it is necessary to explore materials with good ability for adsorption of them. In this study, the structure of armchair graphene (3,3) with a length of 10 Å was optimized using quantum mechanical calculations, and then it was functionalized with hydroxyl and fluorine groups to interact with environmental pollutants such as methane, chlorofluoromethane (R-31) and chlorodifluoromethane (R-22). Adsorption of these substances comprehensively on graphene functionalized with O-H···F groups and virgin graphene from It was investigated through quantum mechanical calculations, molecular dynamics, and Monte Carlo simulations. Energy data, structural parameters, electronic properties, electron charge density, molecular electrostatic potential maps, charge transfer, density of states diagrams, and non-covalent interactions were were analyzed to evaluate adsorption potential. The adsorption sites with the lowest energy value ​​and possible configurations were identified by tracking the Metropolis Monte Carlo probes from the location of the configuration of the absorber-adsorber pairs. Using adsorption isotherms, adsorption energy, binding energies, and isosteric heat values, adsorption effectiveness was considered. The obtained structures showed suitability after the equilibrium and product steps for structural, dynamic, and statistical properties calculations.

In recent years, engineers have faced many structural problems, such as buckling, corrosion and excessive loading in damaged steel structures. The labor force's mistakes during welding and the destruction of the weld are among the many problems in steel structures. Therefore, strengthening and repairing the welding place in steel structures is inevitable. In this article, the influence of polymers reinforced with carbon fibers for strengthening steel studded double columns with defects caused by welding has been investigated. For this purpose, seven steel columns were modelled in Abaqus finite element software. A CONTROL column was modelled as the first sample with no defects and welded all over. The rest of the defective samples were reinforced using CFRP fibers. On the other hand, strengthening using CFRP fibres to improve the location of the defect was investigated in detail for three samples. Reinforcement of these sections using CFRP fibers is not only an effective method to increase the maximum axial force in these columns, but it has also helped to improve resistance and delay local buckling in them. According to the results, it was observed that among all the samples, the maximum bearing capacity is related to the 2UW3 model, and it has increased by 29.9% and 21.7% in the laboratory sample and numerical modelling, respectively, compared to the 2UW3C1 sample. In addition, 2UW3C1 and 2UW1C1 samples have the highest hardness among laboratory and numerical modelling samples, respectively.

Seaweeds are ecologically important and have many applications economically. Inorganic carbon, nitrogen and phosphorus are the main elements needed for photosynthesis and growth of seaweed. Different concentrations of urea and phosphate as fertilizers with the ratio of 1:10 urea to phosphate (P: N = treatment one = 0.2: 2, treatment two = 0.4: 4, treatment three = 6: 0.6 and treatment four = 0.8: 8 mg/l) made treatments and compared to control (without nutrient, as fifth treatment), and their effects on growth of red macro algae, Hypnea musciformis were evaluated in triplicates. Algae sampled from the tidal area of the Oman Sea offshore at the time of the maximum tide and cultured to get optimum biomass for running the experiment. The algae were inoculated into experimental units and cultured for 45 days. A transparent plastic tank containing 40 liters of filtered seawater considered as the experimental unit. At the end of the experiment, the highest and lowest daily growth rate recorded in treatments 2 and control at the rates of 3.3±0.04 and 2.19 ± 0.02 g/day, respectively (p <0.05). These rates in third and fourth treatments were 2.87 ± 0.01 and 2.8 ± 0.01 g/day, respectively, and had a significant increase on growth of algae in comparison to the control (p <0.05). The results indicated that the concentrations of urea and phosphate rates and their ratios in the medium affecting on growth of this alga under outdoor conditions, and at the concentration of 0.4: 4 mg/l and ratio of 1/10 of phosphate to urea algae had the highest growth.

Achieving environmentally sustainable development goals requires identifying new sources of environmental degradation. Therefore, in this study, the impact of shadow economy, information globalization, trade and market size on emissions during the years 1990-2020 in developing countries has been investigated using the Threshold (TAR) model. The results showed that in the short and long term, the shadow economy has a negative impact on environmental pollution in developing countries. In the long run, the co-integration results showed a long-term relationship between the variables in the study. The existence of a long-term relationship between the variables showed that with the increase of the shadow economy, the emission of polluting gases also increased. In the long run, policymakers can use the shadow economy as a tool to influence environmental pollution. In addition, the effect of the threshold index of globalization, trade, market size and shadow economy were estimated in four models. In general, the results of the estimation showed that the shadow economy (SE) has more weight in the output and the emission of pollutant gases increases. Therefore, environmental policymakers and planners to reduce emissions should consider informal and covert activities to make regulations more effective for the environment, as well as the globalization of information and trade to improve the performance of companies and individuals.

Circulation in the fetus has some anatomical features which is of clinical importance. The present study was carried out to investigate the great vessels and duct in the circulatory system of fetal sheep by three techniques of rhodopas cast, angiography, and dissection techniques. Thirty-six male and female fetuses were studied. The age estimation of fetuses was calculated through Crown Rump Length (CRL) measurements and by use of formula for sheep fetus. All fetuses were divided in three groups; group 1 (CRL=12.54±0.52 Cm, Age= 62.08±2.08 days), group 2 (CRL=22±1.31 Cm, Age= 81.9± 5.7 days) and group 3 (CRL=34.6±1.19 Cm, Age= 108.5± 5.38 days), respectively. The structure of the umbilical cord, course of the umbilical vein and arteries, portal vein, ductus venosus, caudal vena cava, aorta, pulmonary trunk, ductus arteriosus, and great arteries and veins of the neck, thoracic and abdominal cavity were studied. The results showed, the vessels and duct of arabian fetal sheep are similar to other ruminants, but there were some differences in arrangment of umblical cord and ductus venosus with equines, dromedary camel and human. Also the fetal sex and age had no effect on the arrangement of vessels and ducts. On the other hand, the results showed that all of the mentioned techniques are capable of assessing the blood vessels and ducts, but are complementary to each other.

 Malaria is one of the most serious parasitic diseases and the major health issue in tropical and subtropical countries.

 This study aimed to investigate the type of infection of female Anopheles mosquitoes to sporozoites of Plasmodium species (Plasmodium vivax and Plasmodium falciparum), using nested polymerase chain reaction (PCR) in southeastern Iran.

 To determine the infections and Plasmodium species using the nested PCR in Sistan and Baluchestan Province (southeastern Iran), 360 female Anopheles mosquitoes were collected from the control villages of Chabahar and Konarak counties and examined by entomology check stations affiliated with Zahedan University of Medical Sciences in the second half of 2018. The mosquitos were caught manually from indoor places (humans and animals) as well as natural and artificial sites, i.e., pit-shelters. After DNA extraction, the molecular analysis was performed by nested PCR.

 Of 200 species collected from Daregas, Owraki, and Bahu Kalat in Chabahar, four Anopheles stephensi (2%) were infected with P. vivax, and of 160 samples collected from the rural districts of Konarak, including Zarabad, Heyan, Islamabad, and Joholu, two An. stephensi (1.25%) were infected with P. falciparum. In this study, no mixed infection of Plasmodium vivax and Plasmodium falciparum were observed.

 The present study showed that the only species infected with Plasmodium in the aforementioned regions was An. stephensi, which was the most frequent species of Anopheles among other species as well. The nested PCR could be the most suitable method for detecting Plasmodium parasites in malaria vectors, among other diagnostic methods.

< p>The Minnesota functionalM062xwith 6-31+G(d, P) basis set has been employed to study interconversions among all-E-, 9Z-, 13Z- and 15Z-β-carotene isomers. Calculations provided essential data concerning the thermodynamic stabilities, the rate constants, activation energies, and HOMO and LUMO of all E⇆Z interconversions of β-carotene. The rate constants for the E⇆Z interconversions have been obtained with the transition-state theory based on the potential energy surface. In terms of energy, all-E-isomer was more stable than the Z-isomers, and the formation of the 9Z-isomer was the slowest interconversion, and raising the temperature increased the rate of interconversions. The tunnelling effect was negligible, and it was not taken into account in determining the rate constant of the E⇆Z interconversions.

This study evaluated the kinetics of mitoxantrone (MTX) releases from Fe3O4-PEG-HA NPs as a drug delivery system in the presence of sodium citrate buffer (pH=5.0) into a dialysis bags at 37 °C using both the UV-vis spectrophotometry technique and statistical patterns. The formal empirical absorbance plot (dotted line) against time was properly fitted by the first-order fitting plot.  To ascertain the best fitted model recognition of character in drug liberation, we calculated several statistical quantities as error standard functions. The release of MTX from the titled was considered with respect to the statistical kinetic patterns of Ritger-Peppas, Sahlin-Peppas, first-order kinetics, Higuchi, and Hixson-Crowell equations. According to the correlation constraint R2 value that emerged from statistical patterns, the first-order model was found as a more comprehensive description than the other patterns for chemical kinetics in drug liberation and the rate of drug release depends on drug concentration.

Health is one of the factors affecting human capital, economic growth and development. Considering the importance of the effect of public health expenditures on health, as well as the increase of the share of public health expenditure on GDP, the aim of this study was to investigate the causality relationship between public health expenditure and health status in upper middle income countries.

The present analytical and causal study was conducted internationally for upper middle income countries. Annual time series data were extracted from the World Bank database for the years 1990–2017. The panel vector self-regression model was estimated and the required tests were performed in Eviews 10 software.

The results show that there is a bidirectional causal relationship between public health spending and health status. Increasing public and private health spending, gross national income, and education spending have a positive effect on increasing life expectancy.

Increasing public health spending leads to improved health and better health results in lower public health spending, so governments' investment in health will lead to improved health, thus adopting policies to increase investment in health infrastructure and technologies, increase services. Public health, subsidies, and national health insurance can help improve the health of society.

The kinetics of reaction between 4-methylaniline (1), dimethyl acetylenedicarboxylate (2) and formaldehyde (4) has been theoretically investigated to gain further insight into the reaction mechanism. The results of theoretical calculations were achieved using the ab initio method at the HF/6-311g (d, p) level of theory in gas phase. The mechanism of this reaction had 5 steps. Theoretical kinetic data (k and Ea), activation parameters (∆G#, ∆S# and ∆H#) and thermodynamic parameters (∆G̊, ∆S̊ and ∆H̊) were calculated for each step and overall reaction. Step 2 of the mechanism was identified as the rate determining step. Also, the method of calculations was improved to B3LYP/6-311g (d, p) level of theory and the reaction mechanism was investigated for all steps of this reaction, again kinetic data and thermodynamic parameters were recalculated at this level of the theory. Improved data at this level was in a good agreement with the HF/6-311g (d, p) level of theory. Theoretical results, altogether were compatible with the literature's reports. As expected, step1 and step3 were recognized as the fast and fastest steps among the other steps. The overall reaction was enthalpy-controlled and proceeded chemically-controlled. In addition, step4 was recognized as a relatively slow, due to the five-membered ring formation in this step was inherently an energetically unfavorable.

The kinetics and mechanism of the reaction between benzaldehyde 1, malononitrile 2 and dimedone 3 in a mixture of ethanol and water as solvents in the presence of fructose as a biodegradable catalyst has been studied by the spectroscopic method (UV-Vis spectrophotometry method). The influence of various parameters (temperature, solvent and concentration) was studied on the reaction by means of the pseudo-first order kinetic model. Based on the experimental data, the overall order of the formation reaction of tetrahydrobenzo[b]pyran followed the second-order kinetics and under pseudo-order conditions the partial orders with respect to 1, 2 and 3 were one, one and zero, respectively. Kinetic values (k and Ea), associated with the activation parameters (ΔH‡, ΔS‡ and ΔG‡) of the reaction were calculated using the Eyring equation from variable temperature in kinetic studies. The initial step of the presented mechanism was determined as a rate-determining step (k1) and t was confirmed using the steady state approximation.

A one-pot synthesis of pyrrole derivatives via reaction between activated carbonyl compounds, primary amines and 1,3-dicarbonyls under solvent-free conditions is described‎.

Sucrose is applied as an efficient catalyst for the three-component reaction consisting of aromatic aldehydes, malononitrile and resorcinol in a mixture of water and ethanol media as green solvents. The advantages of this method are excellent yeild, inexpensive catalyst and more environmentally friendly. Mechanistic insight into the synthesis of 2-amino-4H-chromene included spectral kinetics approaches is revealed. From the temperature, concentration and solvent studies, the activation energy (Ea=102 kJmol-1) and the related kinetic parameters (ΔGǂ=41 kJmol-1, ΔSǂ=195 Jmol-1 and ΔHǂ=99 kJ mol-1) are calculated. The first step of proposed mechanism is recognized as a rate-determining step (k1) and this is confirmed based upon the steady-state approximation.

Acetic acid has been applied as an efficient catalyst and a green solvent for the two–component condensation reaction consisting of benzaldehyde, 2-amino-benzamide. The advantages of this protocol was excellent yield, short reaction time, mild reaction conditions, higher availability, low costs, more environmentally friendly, lack of need for column chromatography and simple work-up procedure. In addition, based on the spectral data, the partial order with respect to each reactant was one. Furthermore, useful information regarding the mechanism of the reaction was obtained from studies of the effect of solvent, concentration and catalyst on the rate of the reaction. The results showed that the first step of the mechanism was a rate-determining step. In the studied temperature range, the second order rate constant (lnk1, lnk1/T) depended on reciprocal temperature was in good agreement with the Arrhenius and Eyring equations. These data provided the suitable plots for calculating the activation energy (Ea = 52.80 kJmol-1) and the related kinetic parameters (ΔG‡ = 63.74 kJmol-1, ΔS‡ = -54.22 Jmol-1 and ΔH‡ = 50.28 kJmol-1) of the reaction.

one-pot synthesis of pyrrole derivatives via reaction between activated carbonyl compounds, primary amines and 1,3-dicarbonyls under solvent-free conditions is described‎.