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Background: Acinetobacter baumannii is a gram-negative pathogen that is highly resistant to antibiotics. This bacterium can cause severe systemic infections, especially in hospitalized patients. Recently, antimicrobial-resistant Acinetobacter baumannii has become a life-threatening pathogen in Iran and around the world.
Materials & Methods: In this study, several Iranian and English databases were systematically searched to find all original and review articles investigating the prevalence of imipenem resistance in their sample size, while mentioning the source of clinical isolates, as well as the prevalence of antimicrobial resistance genes.  
Findings: Among genes, blaOXA-23 with a prevalence of 31% to 100% was responsible for global outbreaks of imipenem-resistant Acinetobacter baumannii and was presented in most of the hospital isolates. Our meta-analysis also revealed that 74.2% of Acinetobacter baumannii were resistant to imipenem in 122 clinical studies.
Conclusion: Our study highlighted a rapid increase in the rate of imipenem resistance in clinical isolates of Acinetobacter baumannii in Iran. The need for periodic antibiotic care system programs to monitor the administration and use of antibiotics

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Aims: Invertase is an enzyme that is widely used in industries. The main source of industrial production of invertase is yeast Saccharomyces cerevisiae (S. cerevisiae). Increasing thermal stability makes an important contribution to improving productivity in related production. The aim of this study was increasing thermal stability of Saccharomyces cerevisiae recombinant protein invertase by site-directed mutagenesis.
Materials and Methods: In the present experimental study, using invertase enzyme from thermophilic bacteria, Thermotoga maritima as template, it was decided to replace the threonine 345 and asparagine 349 amino acid with alanine, using site-directed mutagenesis and in Pichia pastoris, cloning was performed with the SOEing polymerase chain reaction. The activity of natural and mutant recombinant invertase enzymes at different temperatures, different pHs, stability duration, and thermal-performance stability, and Michaelis–Menten kinetics were drawn.
Findings: The thermal-structural stability of the natural and mutant invertease enzymes at 55°C showed that the mutant enzyme had a higher thermal stability at 55°C compared with the natural enzyme. Both natural and mutant enzymes exhibited a similar trend in functional stability. Reduction of K_m and increase of V_max in sucrose substrate and 5-fold increase in K_cat/K_m ratio of mutant enzyme was observed.
Conclusion: Site-directed mutagenesis has no negative effect on the amount of production as well as the secretion of recombinant protein invertase and increases enzyme activity. The mutant enzyme has a higher structural stability than the natural enzyme without altering its functional stability.

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Plant endophytes deployment at the field level affects the productivity of agricultural products. Savory Satureja khuzestanica Jamzad is a valuable medicinal plant native to Iran. In this study, in order to improve the quantitative and qualitative yield of the plant, the development of a suitable method for inoculation of native fungal endophytes to S. khuzestanica is surveyed. Three fungal endophytes (P.I.S.7, D.2.F.1 and D.1.S.1), isolated from savory plants, were inoculated on S. khuzestanica using four different methods (stem injection, foliar spray, soil drench and adding fungi to the soil in granular form) and their impact on plant's growth and its physiological response was analyzed. All inoculation methods, except adding granular form of fungi to the soil, resulted in endophytic colonization of the savory tissues. However, P.I.S.7 isolate was not established in these plants using any inoculated methods. Extent of fungal colonization showed a significant difference with the inoculation method, such that foliar spray had the highest colonization level, followed by stem injection and root drench. The highest rate of fungal colonization belonged to D.1.S.1. isolate. Spraying leaves and stem injection with endophytic fungi, especially in the case of D.1.S.1, significantly enhanced the morphological and physiological characteristics of host plants and the percentage of essential oil yields in these plants. All in all, using the D.1.S.1 isolate and foliar spray method led to savory plants' improved quantitative and qualitative product.

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Aim: Recognition of habitat status and ecological responses of species to environmental variables are prerequisites for better management and providing the ecological needs of each species. This study assessed the current status and distribution of Viburnum lantana L. and described its ecological characteristics in the lowest limit of its distribution in the northern hemisphere, Arasbaran forests.
Materials and Methods: The presence sites of Viburnum lantana L. (wayfaring trees) were selected based on the field observations and library sources, then to collect data, the 114 circular samples with a radius of 17.84 m were laid systematically and randomly out. Within each sampling area the characteristics of each woody species including species name, diameter at the breast height (DBH) and the height of all wayfaring trees and other species were measured. The relative importance value (RIV) of species across all sample plots was calculated to describe the dominant species composition.
 

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In this study, the aerial parts of Pimpinella puberula were collected from Ramhormoz and Mashhad (Khuzestan and Khorasan Provinces) at the vegetative, flowering and seeding stages. Essential oils from the whole aerial parts as well as stem/leaf, inflorescence, unripe and ripe seeds, were isolated by hydro-distillation. The yields of essential oil obtained from the Ramhormoz samples were 0.49%, 0.31%, 3.81%, 6.01% and 1.80% w/w, and from those from Mashhad were 0.96%, 0.87%, 3.59%, 6.94% and 4.96% w/w, respectively. The oils from different parts of plant were also analyzed by GC and GC/MS. Limonene was the major constituent in all the oils (21.7%-82.4%), followed by pregeijerene (14.6%-55.4%) and geijerene (7.2%- 11.7%). Methyl eugenol and elemicine, however were only found in the Ramhormoz oil samples. The antimicrobial activity of the oils was determined using the disk diffusion method against Gram positive bacteria (Bacillus subtilis, Bacillus cereus, Micrococcus luteus and Staphylococcus aureus), Gram negative bacteria (Yersinia entrocolitica, Klebsiella oxytoca, Serratia marcescens, Escherichia coli and Pseudomonas aeruginosa) and yeast (Candida albicans). Results showed a significant difference between Gram positive and Gram negative bacteria in their susceptibility to the oil, although Gram positive bacteria were more susceptible to the antimicrobial activity of P. puberula oil. In addition, the antimicrobial activity of samples collected from Ramhormoz were more than of those from Mashhad.

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Aims: Stressful conditions can lead to increased emotional and mental distress. This study aimed to evaluate perceived stress and eating disorders among a sample of Iranian nurses.
Instrument & Methods: This cross-sectional study was conducted on 149 nurses from hospitals in Bojnurd City, Iran. Eating disorders and perceived stress were assessed using the valid Persian version of the Eating Disorders Scale and the valid Persian version of the Perceived Stress Scale, respectively.
Findings: The nurses exhibited moderate to high levels of perceived stress. Overall eating disorder and anorexia nervosa scores were higher among single individuals compared to married ones. Overall eating disorder scores were elevated in individuals without personal experiences of illness or without experiences of losing family members due to illness, while bulimia scores were higher in nurses who had experienced the loss of family members due to illness compared to those without such experiences. Significant correlations were observed between the overall eating disorder (r=0.20, p=0.01) and anorexia nervosa (r=0.38, p<0.001) and physical activity level and age.
Conclusion: The nurses demonstrate moderate to high levels of perceived stress, and their overall eating disorder is significantly correlated with their physical activity level and age.

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The incompressible Newtonian and non-Newtonian fluid flow in a tube with disk insert is studied numerically using finite volume and boundary fitted coordinate method. The non-Newtonian fluid is time independent purely viscous that is simulated by the power law model. The effects of power law index, thickness, aspect ratio, Prandtl number and the distance between insert tubes on heat transfer, pressure drop and overall enhancement ratio (OER) are investigated for the Reynolds numbers 500, 1000 and 1500. The results show that the effect of power law index on pressure drop and overall enhancement ratio is more than the other parameters.

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Objective: Despite toxic effects of some essential oils, their use is not under control. With a view to increasing trend of utilisation of herbal products, some biological aspects of Thymus daenensis are repoted here for the first time. Materials and Methods: Antimicrobial properties using disk diffusion and dilution tests, nitric oxide radical scavenging by Marcocci et al method and cytotoxic properties employing dimethylthiazolyl diphenyltetrazolium bromide reduction test were carried out with Thymus daenensis and commercial Thyme essential oils and their main chemical compound, thymol. Results: The microbial sensitivity to the oils were in Candida albicans> E.coli> S.aureus> P. aeruginosa order. The minimum inhibitory and microbicidal concentrations were in the range of 0.04-10mg/ml. Nitric oxide radical scavenging was dose dependent with an IC50 of 5, 75, 863 µg, and total phenolics of 644.07±6.79, 16.94±2.55, 10.33±2.31µg Gallic acid equivalent per mg sample and total flavonoid content of 73.51±1.34, 0.56±0.02, 0.21±0.09 mg Catechin equivalent per gram T.daenensis oil, commercial thyme oil and thymol respectively. The concentrations from T.daenensis oil, commercial thyme oil and thymol required to exert 50% fatal effect (IC50) on healthy human normal lymphocytes and Hela cells were 1455, 12.10, 2867 and 4.95, 3.61, 1730 µg respectively. Conclusion: T. daenensis with its good antimicrobial property can prevent formation of toxic reactive oxygen species and as a good antioxidant, it can directly scavenge NO and O2−. With a view to cancerous cells killing properties of the oils at their lowest concentrations without fatal effect on normal healthy cells, feasibility of their application in combating cancerous cells may be promising.

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Gastric cancer is one of the most common cancers in the world. Its treatments are costly and can cause severe side effects. As a result, treatments with natural compounds, well-established therapeutics, or combinations of both groups may be effective alternatives. p-Coumaric acid (pCA) and metformin (Met) are among such anticancer treatments. Epithelial-mesenchymal transition (EMT) is a multi-purpose process that plays a critical role in gastric cancer. This process involves a complex network of biological markers participating in gastric cancer initiation and metastasis. Subsequently, the agents downregulating the expression of EMT markers may be potential anti-gastric cancer therapeutics. Because the effects of pCA, Met, and their combination on the expression of EMT markers ZEB1, Snail2, Vimentin, and VEGFA have not been inspected, the present study aimed at assessing these effects. MTT assay determined the cytotoxicity of pCA and Met on the AGS cells for 48 hours. Real-time PCR was used to evaluate the changes in the expression levels of these EMT genes after 48 hours. A combination of pCA and Met downregulated the expression of ZEB1 and Vimentin genes at low, non-cytotoxic concentrations. Therefore, they may be potential candidates for further investigations in fighting against gastric cancer.
 

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Many parameters affect essential oil yield and chemical composition of aromatic plants. For obtaining the highest quantity and quality of essential oil, it is necessary to know the proper methods of drying and distillation. The aim of this research was to investigate the influence of drying and extraction methods on the yield and chemical composition of the essential oil of Eucalyptus sargentii. The fresh leaves of Eucalyptus sargentii, cultivated in Kashan (central region of Iran), were collected in the middle of spring and dried by five different drying methods: sun-drying, shade-drying, and oven-drying at 30, 40 and 50°C. The essential oils of every treatment were obtained by hydro-distillation in three replication. In addition, the essential oil of shade-dried sample was obtained by two other distillation methods, namely, water- and steam-distillation and direct steam-distillation. The oils were analyzed by capillary GC and GC-MS. Statistical analysis showed significant difference between oil yield (w/w) of the shade-dried sample (3.39%) compared to oven-dried at 40°C (2.92%), sun-dried (2.66%), oven-dried at 30°C (2.59%) and oven-dried at 50°C (2.30%). The oil content of the shade-dried sample obtained by hydro-distillation (3.39%) was higher than those of the water and steam distillation (2.89%) and steam distillation (1.35%). Twenty-three components were identified in the oil of E. sargentii in the different drying methods, including 1,8-cineole (57.9-65.8%) and α-pinene (11.3-28.3%) as main components. Twenty-four compounds were characterized in the oils of different distillation methods, including 1,8-cineole (61.2-66.6%) and α-pinene (19.7-28.3%) as the major compounds. Among the different drying methods, shade-dried samples produced the highest oil yield and 1,8-cineole content, while in different distillation methods, hydro-distillation produced the highest oil yield, but the highest percentage of 1,8-cineole was obtained by water and steam distillation.

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Tumor induced angiogenesis is the bridge between benign and malignant tumor growth stages. In this process, growth and migration of endothelial cells build capillaries to supply the tumor with blood for its further growth. Regarding the importance of capillary formation and blood flow in angiogenesis, simulation of this phenomenon plays important role in tumor growth and cancer development studies. In this work, considering intracellular, cellular, and extracellular scales a mathematical model of tumor-induced angiogenesis is used to consider mechanical effects of extracellular matrix on growth and migration of endothelial cells. These effects are matrix density and its fiber length. In this study, to model cellular dynamics, a discrete lattice based Monte Carlo method is used. Results show that migration of endothelial cells and development of capillaries are possible in a specified range of matrix density and matrix fiber length. Based on the results, medium matrix densities and low fiber length provide a suitable environment for capillaries growth and development. The model is a promising tool for modeling tumor induced angiogenesis and is a base for development of models for loop formation and blood flow in capillaries around tumor.

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Nowadays, solid tumor modeling and simulation results are used to predict how therapeutic drugs are transported to tumor cells by blood flow through capillaries and fluid flow in tissues. This model involves processes such as fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. In this paper, a complete model of interstitial fluid flow in tumor and normal tissue is presented with considering multi scale of solution such as blood flow through a capillary (as the smallest scale) to interstitial flow (as the biggest scale). The advanced mathematical model is used to generate a capillary network induce by tumor with two parent vessel around the tumor for the first time. In the following, the blood flow is modeled through the network with considering the non-continuous behavior of blood rheology and adaptability of capillary diameter to hemodynamics and metabolic stimuli. This flow is simultaneously simulated with interstitial flow which is coupled to blood flow through capillary with extravascular flow. The results predict elevated interstitial pressure in tumor region and heterogeneous capillary network which are introduced as barriers to drug delivery.

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In the present study, the mixing fluids flow in the twin and circular mixers is investigated by using an improved robust weakly compressible Smoothed Particle Hydrodynamics method. In order to remove the Smoothed Particle Hydrodynamics complications and according to a predictive corrective scheme, a robust modified algorithm which uses the advanced second order discretization, pressure velocity decoupling, kernel gradient corrections and shifting algorithm is offered. After the verification and validation of the present algorithm for the moving boundary problems, the present algorithm is applied for investigation of the mixing behaviors of the two-blade circular and twin chamber mixers. By investigation of the mixing paths, the proper geometry for the two-blade mixers is proposed and examined. The effects of the rotation direction of the blades, geometry and Reynolds number on the mixing rate are investigated. The results show that the twin chamber mixer can improve the mixing performance over 60% in comparison with the circular chamber mixer while the case with circular chamber and same direction rotation of the blades has the weakest performance among the cases which have been examined.

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Weirs possess an essential role in dam safety and should spill floods with high return period. The designers can enhance the width of the weirs to increase the discharge capacity. But this has sometomes topography and economic limitations. Arced weirs can be considered as an alternative. A arced weir is a arcuate of a circle in plan-view that provides an increase in crest length for a given channel width that increas the flow capacity for the same head. Also when modification and capacity increase in existing spillways are necessary, this structure is recommended. In this paper, the hydraulic performance of arced weirs located in a reservoir has been studied experimentally. Firstly, dimensionless parameters affecting the performance of arced weirs is introduced using Buckingham π theorem. Then effect of arc angle (θ) and head water ratio (H0/P) on hydraulic performance of arced weirs was experimentally investigated and hydraulic performance of the tested arced weir geometries was compared with a linear configuration. For this purpose, Arches with different radius of curvature from linear to semi-circular configurations ( ) and various head water ratio Were studied. To simulate reservoir conditions, a reservoir simulator was designed and built. Laboratory observations show that the converging of flow over a arced weir causes a locally bulge in the downstream of the weir. This phenomenon was named as flow mound. Results show that arc angle (θ) and head water ratio (H0/P) have a direct effect on the flow mound and an increase in each of them leads to mound height rise. The head-discharge relationship for arced weirs was determined by using a general form of the rectangular weir equation. Data from physical models were used to determine discharge and upstream head for the flat crested weirs installed in the reservoir. from discharge curves, it was found that with increasing angle of weir, that provide an increase in crest length for a given channel width, flow capacity increases for a given upstream head. Discharge coefficients as a function of H0/P for arced weirs are also presented and is compared with linear configuration. The results show that with increasing H0/P, discharge coefficient is declined for each tested configuration. Also with increasingθ , that leads to greater convergence of flow passing over the weirs, discharge coefficient decreases. Efficiency parameter is defined as the ratio of discharge of arced weir to that of liner weir with a same width. From efficiency curves it can be understood that the semi-circular weir can improve efficiency up to about 45%. However for all tested weirs , efficiency decreases with increasing H0/P and it gets close to 1. Finally, based on the results and limitations of this study, a methodology for the design of arced weirs located in the reservoir is presented. By using this method, the geometric parameters if an arced weir that is able to pass a certain flow rate for a given hydraulic head, will be determined.

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In this present study, the mixing of two incompressible miscible fluids with different density and viscosity has been investigated in a two-dimensional microchannel equipped with an oscillating stirrer in different excitation frequency. Although most studies in the field of fluid mixing, have been studied the mixer performance when the two fluids were absolutely identical, but the mixing make sense when two fluids has been non-uniformity such as different temperature, concentration or properties. The aim of this study is to evaluating the effect of various properties of the fluids in mixer performance and mixing value. Simulation has been performed in Re=100 and Sc=10, between 0.1 to 1 strouhal number by using element based finite volume method by means of commercial code CFX. Mixer performance has been evaluated in three different modes: mixing of two identical fluids, mixing of two fluids with different density and mixing of two fluids with different viscosity. The results show that, mixing of the fluids with different properties leads to change in mixer performance, and has unique performance in each case. In comparison with similar properties fluids, mixing of fluids with different viscosity and density show lesser inclined in mixing. It has been shown that variation of strouhal number has lesser effect on mixing index changes. The ratio of maximum mixing index changes to base mixing index in the case of different density and viscosity is 54.01 and 51.15 percent, respectively, while the value is 577.94 percent for the mixing of similar fluids.

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The Nowadays the use of modified compartmental model in order to estimate the transmission of tracer to the cells or cancerous tissues is focused extensively. The modified compartmental model includes two compartments, one to predict the mass transfer from vessels and a compartment to describe metabolism occurring inside the tissue. In the modified compartmental model, the kinetic rate constants can be obtained by estimating the parameters between the compartments. The accurate calculation (estimation) of rate factors over the region under study has an important role in coinciding the time activity curve obtained by compartmental modeling and the curve resulted from experimental data which is the main tool to distinguish the cancerous and normal tissues. Today most of doctors us the standard uptake value to study the amount of tracer uptake in cancer suspicious regions in order to have a more accurate recognition of cancerous and normal tissues. In this paper the Patlak graphical analysis method and standard uptake value (SUV) method are used to predict the tracer uptake into the tissue. A comparison between the uptake parameter resulted from the two mentioned methods with the uptake parameter obtained by modified compartmental model in a rat shows the accuracy of the Patlak method in distinguishing the cancerous tissues from the normal ones.

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The cavity problem always has been considered as a classic and fundamental problem. Specific materials like Bingham viscoplastic which is sort of Non-newtonian fluids shows resistance in a certain range of stress, calling yield stress, and almost acts like rigid body in this limited area. In case of increase applied stress, flows like fluid. Considering heat transfer in this type of material and investigate it, yield stress and viscosity variations with temperature as in practice we face will not be far-fetched. In the present work the numerical solution of the problem of Bingham material inside lid-driven cavity, investigating fluid flow and heat transfer in view of the changes in material properties has been done and results have shown with change in dimensionless numbers and parameters of Re=10-1000, Bn=1-2000, Pr=0.01-100 and E=5000-50000. In this study, using the finite volume method to discretize governing equations and the use of collocated grid, effect of viscosity and yield stress dependence to temperature compared with independence mode and then distribution of horizontal and vertical components of velocity, yield areas and flow inside cavity, center of vortex and then heat transfer due to the stream lines next to side walls, have been analyzed.

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In this article, the ghost fluid-lattice Boltzmann method, used to simulate the curved boundaries is combined with an extrapolation based refilling method to cope with the moving curved boundaries, where in each iteration some of the solid nodes step into the fluid domain. The refilling method is used to approximate the unknown density and internal energy distribution functions of such solid nodes. To examine the accuracy of the presented method, several case studies are considered. From those case studies, natural convection problem between to concentric and eccentric cylinders as well as heat transfer from a cylinder in a cross flow are considered to validate the ghost-fluid lattice Boltzmann method used to simulate the hydrodynamic and thermal conditions at the curved boundaries. To test the accuracy of the employed refilling method, sedimentation of a single isothermal cold particle in a vertical channel investigated. The results show that the presented ghost fluid-lattice Boltzmann method with refilling is capable of simulating the moving thermal curved boundaries with excellent accuracy.

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In this paper, a numerical algorithm based inverse method is used to estimate effective diffusion coefficient by using experimental tracer distribution. The Algorithm uses factitious experimental data which are produced by adding noise to numerical data obtained from direct problem. A comprehensive model (Diffusion-Convection-Reaction) is used to derive PET tracer distribution in tumor tissue with microvasculature network. This model was used because of considering all transport phenomena in tissue. In this work to achieve accurate distribution of tracer in tumor tissue, convection diffusion reaction equation which is a PDE is implemented. The proposed tracer in this work is Fluorodeoxyglucose (18F). Solution of inverse problem for estimating effective Diffusion Coefficient is based on minimization of least squares norm. In this work Levenberg-Marquardt technique is applied. Solution of parameter estimation problem require calculation of sensitivity matrix which elements are sensitivity coefficients. Sensitivity coefficients shows differentiation of Tracer concentration with respect to Effective Diffusion coefficient variation is calculated using first derivation of concentration equation. The equations of concentration distribution and sensitivity coefficients are solved using Finite volume method. The results show that the numerical algorithm is able to estimate the effective diffusion coefficient in tissue.

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Today by usage of the simulation of normal tissue and the process of material diffusion in body, the place of tumor can be predicted. By considering the tumor tissue, its growth can be evaluated. The fluid flow in the capillary, its effects on the adjacent tissue and the diffusion of molecules from capillary wall are considered in these kinds of simulation. Cancer cells due to the high rate of dividing cells, have a low level of oxygen. This lack of oxygen is called Hypoxia, so by using of different invasive and noninvasive manners, the amount of oxygen is measured in the body. The PET device indicates the oxygen distribution by use of special tracers in the several parts of body. In this essay by considering a real capillary network, the blood flow had been simulated, then by taking to the account of its effects on the tissue, oxygen pressure and the concentration of tracer had been simulated at the same time. At the end, the concentration of free and bind tracer is shown and its changes by the time is analyzed.