Nd:YAG end-pumped zigzag multi-pass slab amplifier optimization: numerical and experimental study regarding the saturation effects.

A numerical modeling of Nd:YAG end-pumped zigzag multi-pass slab amplifier is developed. Spatial dependent rate equations have been solved taking into consideration the pump and laser beam saturation effects with regard to overlap correction of the signal path through gain medium. Based on our results, efficient amplifier structure with optimized output power could be designed with respect to the change in the number of signal beam-pass, doping concentration and slab length. In order to verify our modeling an experimental setup is designed.

WITHDRAWN: Incidence and mortality of COVID-19 in Iranian multiple sclerosis patients treated with disease-modifying therapies.

This article has been withdrawn at the request of the authors and editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.

Weak reversible cross links may decrease the strength of aligned fiber bundles.

Reversible cross-linking is an effective strategy to specifically tailor the mechanical properties of polymeric materials that can be found in a variety of biological as well as man-made materials. Using a simple model in this paper the influence of weak, reversible cross-links on the mechanical properties of aligned fiber bundles is investigated. Special emphasis in this analysis is put on the strength of the investigated structures. Using Monte Carlo methods two topologies of cross-links exceeding the strength of the covalent backbone are studied. Most surprisingly only two cross-links are sufficient to break the backbone of a multi chain system, resulting in a reduced strength of the material. The found effect crucially depends on the ratio of inter- to intra-chain cross-links and, thus, on the grafting density that determines this ratio.

Effects of probiotic yogurt consumption on metabolic factors in individuals with nonalcoholic fatty liver disease.

The aim of this study was to investigate the effects of probiotic yogurt consumption on some metabolic factors in nonalcoholic fatty liver disease (NAFLD) patients. This double-blind, randomized, controlled clinical trial was conducted on 72 patients with NAFLD (33 males and 39 females) aged 23 to 63 yr. Subjects in the intervention group (n=36) consumed 300 g/d of probiotic yogurt containing Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12 and those in the control group (n=36) consumed 300 g/d of conventional yogurt for 8 wk. Fasting blood samples, anthropometric measurements, and dietary records (24h/d for 3 d) were collected at baseline and at the end of the trial. Probiotic yogurt consumption resulted in reductions of 4.67, 5.42, 4.1, and 6.92% in serum levels of alanine aminotransferase, aspartate aminotransferase, total cholesterol, and low-density lipoprotein cholesterol, respectively, compared with control group. No significant changes were observed in levels of serum glucose, triglycerides, or high-density lipoprotein cholesterol in either group. Probiotic yogurt consumption improved hepatic enzymes, serum total cholesterol, and low-density lipoprotein cholesterol levels in studied subjects and might be useful in management of NAFLD risk factors.

Sensitivity analysis of natural convection in a porous cavity filled with nanofluid and equipped with horizontal fins using various optimization methods and MRT-LB.

In the present study, natural convection heat transfer is investigated in a porous cavity filled with Cu/water nanofluid and equipped with horizontal fins. Optimization and sensitivity analysis of the fin's geometry, porous medium and nanofluid properties to maximize heat transfer rate is the aim of this work. To achieve this purpose, a design space is created by input parameters which include length, number of fins, distance between fins, porosity, Darcy number and volumetric fraction of the nanoparticles. Several tools have been used to implement optimization methods including the Taguchi method (TM) for design points generation, sensitivity analysis of design variables by using signal-to-noise ratio (SNR) and analysis of variance (ANOVA), response surface method (RSM) for interpolation and regression by using nonparametric regression, and genetic algorithm (GA) for finding optimum design point. The double multi-relaxation time lattice Boltzmann method (MRT-LBM) is used to analyze and simulate the flow field and heat transfer in each design point. The results show that the optimal configuration leads to an average Nusselt number of 5.56. This optimal configuration is at the length of fins L/2, the number of fins 2, the distance between fins L/12, porosity 0.8, Darcy number 0.1, and the volumetric fraction of the nanoparticles 0.02. By using the SNR results, the Darcy number and the number of fins have the most and the least effect in maximizing the average Nusselt number, respectively. The ANOVA results and global sensitivity analysis (GSA) findings further validated this conclusion.

Antidepressant activity of Hibiscus esculentus L.

OBJECTIVES: Hibiscus (H.) esculentus L. (Okra) is distributed from Africa to Asia, Southern European and America and widely used as food. The aim of present study was to investigate antidepressant activity of Okra seeds and leaves. MATERIALS AND METHODS: Antidepressant activity of methanolic extracts were evaluated by forced swimming test (FST) and tail suspension tests (TST). Also, total phenol and flavonoid contents were measured by Folin Ciocalteau and AlCl3 assays, respectively. RESULTS: Phenol and flavonoid contents of extracts were determined as gallic acid and quercetin equivalents from a calibration curve, respectively. Extracts showed good antidepressant activity in both FST and TST. The extracts shortened remarkably the immobility period in FST and TST and exhibited a dose dependent activity. Seeds extract in 250, 500 and 750 mg kg-1 showed significant activity as compared to control (p < 0.001). Both extracts at 750 mg kg-1 showed similar activity as imipramine 15 mg kg-1 (p > 0.05) in TST. Extracts contained high amount of phenol and flavonoids. No mortality has been observed up to 2 g kg-1 for seeds and 2.5 g kg-1 for leaves. CONCLUSIONS: These results introduced H. esculentus seeds and leaves as an easily accessible and edible source of natural antidepressant.

Antihemolytic activity and mineral contents of Juglans regia L. flowers.

OBJECTIVES: Juglans (J.) regia L. is known to possess many biological properties. In this study, antihemolytic activity of methanol extract of Juglans regia L. flower were investigated. MATERIALS AND METHODS: Antihemolytic activities of Juglans regia L. flowers were evaluated by various in vitro assays. In addition, scavenging of hydrogen peroxide and mineral contents of flowers were determined using atomic absorption spectroscopy. RESULTS: Extract showed good antihemolytic activity against H2O2 and CuOOH induced hemolysis in comparison with control. Extract was capable of scavenging H2O2 in a concentration dependent manner. IC50 for H2O2 scavenging activity was 311±12.8 µg ml-1. The amount of eight elements was determined and was in the order: Mn > Cu > Fe > Zn. CONCLUSIONS: Our study indicate that J. regia flower has remarkable antihemolytic activity, which maybe result of its high phenol and flavonoid contents, especially quercetin.

Anticonvulsant activity of Hypericum scabrum L.; possible mechanism involved.

OBJECTIVES: Hypericum (H.) spp. has been used in traditional medicine for their anticonvulsant effect for many years. In spite of many works on this genus, little is known about H. scabrum. In this work, anticonvulsant activity of H. scabrum was investigated. MATERIALS AND METHODS: Anticonvulsant activity of aqueous extract was evaluated by pentylenetetrazole (PTZ) induced convulsion and picrotoxin induced convulsion. Also, nitric oxide radical scavenging was investigated as a possible mechanism involved. RESULTS: Extract (125-500 mg kg-1, i.p.) significantly delayed the onset of PTZ induced convulsion. At 500 mg kg-1, 100% protection against mortality was observed. At this dose, it significantly prolonged the onset of picrotoxin induced convulsion in mice, too. It showed significant nitric oxide radical scavenging activity. CONCLUSIONS: Mechanism of anticonvulsant activity may be through GABA and/or nitric oxide pathway.

Antioxidant and antihemolytic activities of flavonoid rich fractions of Artemisia tschernieviana Besser.

OBJECTIVES: Artemisia (Asteraceae) contains more than 400 species. Many of the plants belonging to this genus are known to possess biological properties. In this study, antioxidant and antihemolytic activities of flavonoid rich fractions of A. tschernieviana Besser were evaluated. MATERIAL AND METHODS: Plant aerial parts were extracted with 60% acetone. Extract was fractionated sequentially with hexane (HE), ethyl acetate (EA) and water (AQ). Antioxidant and antihemolytic activities of these fractions were assessed. Their antihemolytic activity was determined by H2O2 and cumene hydroperoxide induced hemolysis models. RESULTS: AQ fraction showed very powerful activity in 1,1-disphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity with IC50 = 0.12 +/- 0.01 microg ml(-1) that was better than controls (vitamin C, quercetin and butylated hydroxyanisole (BHA)). This fraction showed very powerful reducing power assay that was better than vitamin C (p < 0.01). EA fraction showed higher activity in scavenging nitric oxide with IC50 = 0.14 +/- 0.04 microg ml(-1). In iron chelating activity HE fraction showed the best activity (IC50 = 162.2 +/- 8.7 microg ml(-1)). In scavenging of hydrogen peroxide, AQ fraction showed better activity than control group. This fraction had higher phenol and flavonoid contents. EA fraction showed higher antihemolytic activity with IC50 = 728.8 +/- 29 microg ml(-1). CONCLUSIONS: The fractions show very good activities in studied models. Aqueous fractions showed better activity than the others in nearly all tested models. These results can be useful as a starting point of view for further applications of A. tschernieviana aerial parts or its constituents in pharmaceutical preparations after performing clinical in vivo researches.

Biological activities of flavonoid-rich fraction of Eryngium caucasicum Trautv.

OBJECTIVES: Eryngium (E.) caucasicum was found as a new cultivated vegetable plant in northern Iran and used in several local foods. Little information is available on biological properties of E. caucasicum. In this work antioxidant activity of flavonoid-rich fraction of this plant was investigated by eight in vitro assay systems. MATERIALS AND METHODS: 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), nitric oxide and hydrogen peroxide scavenging activities, Fe2+ chelating ability, reducing power and hemoglobin-induced linoleic acid peroxidation were used to evaluate antioxidant activities. Antihemolytic activities were evaluated against CuOOH and H2O2 induced hemolysis in rat erythrocyte. RESULTS: IC50 for DPPH scavenging activity was 391.2 +/- 14.9, 706.6 +/- 22.3 and 779.7 +/- 16.7 microg ml(-1) for aqueous (AQ), ethyl acetate (EA) and n-hexane (HE) fractions, respectively. There was no difference between reducing power of AQ fraction activity and vitamin C (p > 0.05). IC50 for NO radical-scavenging activity was in order of AQ (133.5 +/- 6.2 microg ml(-1)) > EA (350.1 +/- 14.8 microg ml(-1)) > and HE (639.9 +/- 21.7 microg ml(-1)) fractions, respectively. Extracts showed weak Fe2+ chelating ability. HE fraction showed better activity (173.5 +/- 9.6 microg ml(-1)). Extracts exhibited weak hydrogen peroxide scavenging activity but exhibited very good antioxidant activity against the hemoglobin-induced linoleic acid peroxidation. There was no significant difference between AQ fraction and vitamin C (p > 0.01). Fractions delayed the onset of the CuOOH induced hemolysis. AQ fraction showed very high total phenol and flavonoid contents which was higher than other fractions. High phenol and flavonoid content of AQ fraction may lead to its better antioxidant activity. CONCLUSIONS: E. caucasicum fractions exhibited different levels of antioxidant and antihemolytic activities in all tested models. These results can be useful as a starting point of view for further applications of E. caucasicum aerial parts or its constituents in pharmaceutical preparations.

Hepatoprotective activity of Allium paradoxum.

OBJECTIVE: Recent studies show that free radicals are important mediators of hepatic injury induced by carbon tetrachloride. Allium (A.) paradoxum showed antioxidant and antihemolytic activities. This work was conduct to determine the possible protective effect of this plant against hepatotoxicity. MATERIALS AND METHODS: Subcutaneous injection of 3 ml/kg carbon tetrachloride diluted in olive oil (1:1 dilution) was employed for inducing acute liver toxicity. The protective effect of aerial parts and bulbs of A. paradoxum at flowering stage were determined. RESULTS: Both aerial parts and bulbs extracts at the doses 500 and 750 mg/kg, i.p. offered significant hepatoprotective effect by reducing the serum marker enzymes, serum aspartate aminotransferase (AST) and alkaline phosphatase (ALP). Histopathological studies further confirmed the hepatoprotective activity of aerial parts and bulbs extracts when compared with the CCl4 treated groups. CONCLUSION: Extracts of A. paradoxum showed significant hepatoprotective activity compared with control group.

In vitro antioxidant activity of flower, seed and leaves of Alcea hyrcana Grossh.

OBJECTIVES: Alcea hyrcana Grossh (A. hyrcana Grossh) (malvacea), is native to northern of Iran. Many of the plants belonging to the genus Alcea are known to possess ethnomedical and biological properties. In this study, antioxidant activities of methanolic extracts of flower, seed and leaves of Alcea hyrcana Grossh were evaluated by various antioxidant assays. MATERIAL AND METHODS: 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), nitric oxide and hydrogen peroxide scavenging activities, Fe2+ chelating ability, reducing power and hemoglobin-induced linoleic acid peroxidation test were used to evaluate antioxidant activities. The total amount of phenolic compounds was determined as gallic acid equivalents and total flavonoid contents were calculated as quercetin equivalents from a calibration curve. Total phenolic and flavonoid contents also have been determined. RESULTS: All extracts showed good antioxidant activities. The A. hyrcana Grossh leaves extract exhibited strong ferrous chelating activity with IC50 = 0.11 +/- 0.01 mg ml(-1), nitric oxide radical scavenging with IC50 = 0.45 +/- 0.01 mg ml(-1) and better reducing power activity than other extracts. The seeds extract showed high scavenging activity against free radicals, including both the hydrogen peroxide and DPPH radicals. Only leaves extract had good activity in linoleic acid model. Seeds extract had significant higher total phenol (68.9 +/- 3.7 mg gallic acid equivalent/g of extract powder) and leaves had higher flavonoids contents (28.3 +/- 2.6 mg quercetin equivalent/g of extract powder) than other parts. CONCLUSIONS: The leaves, seed and flower extracts of A. hyrcana Grossh exhibited good but different levels of antioxidant activity in all the models studied. The extracts had good iron chelation, H2O2 and nitric oxide scavenging activities. Antioxidant activities may be attributed, at least in part, to the presence of phenols and flavonoids.

Antioxidant activity of hydroalcholic extract of Ferula gummosa Boiss roots.

OBJECTIVES: Ferula gummosa Boiss is native to central Asia. This plant has traditionally been used in the treatment of many diseases. The antihypoxic and antioxidant activities of Ferula gummosa roots were investigated. MATERIAL AND METHODS: 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), nitric oxide and hydrogen peroxide scavenging activities, Fe2+ chelating ability, reducing power and hemoglobin-induced linoleic acid peroxidation were used to evaluate antioxidant activities. Antihemolytic activity was evaluated by H2O2 induced hemolysis in rat erythrocytes. The total amount of phenolic compounds was determined as gallic acid equivalents and total flavonoid contents were calculated as quercetin equivalents from a calibration curve. RESULTS: The extracts showed moderate antioxidant activity in some models. IC50 for DPPH radical-scavenging activity was 579.6 +/- 19.4 microg/ml. The extracts showed weak nitric oxide-scavenging activity between 0.1 and 1.6 mg ml(-1) but showed good Fe2+ chelating ability. IC50 was 895.5 +/- 24.1 microg/ml. The extract also exhibited low antioxidant activity in the linoleic acid model but were capable of scavenging hydrogen peroxide in a concentration dependent manner. Tested extract show moderate activity in H2O2 induced hemolysis in rat erythrocytes which was not comparable with vitamin C. CONCLUSIONS: F. gummosa Boiss root showed different level antioxidant and antihemolytic activities. Biological effects may be attributed, at least in part, to the presence of phenols and flavonoids in the extract.

Antioxidant and antihaemolytic activities of Ferula foetida regel (Umbelliferae).

OBJECTIVES: The Ferula genus (Umbelliferae) is a rich source of gum-resin and is much utilized in folklore medicine. This study is designed to examine antioxidant and antihaemolytic activities of Ferula foetida regel flower, stem and leaf extracts. MATERIALS AND METHODS: 1,1-Diphenyl-2-picryl hydrazyl radical (DPPH), nitric oxide and H2O2 scavenging activities, Fe2+ chelating ability, reducing power and hemoglobin-induced linoleic acid peroxidation were used to evaluate antioxidant activities. Antihaemolytic activity was evaluated by H2O2 induced hemolysis in rat erythrocyte. Total phenolic compounds were determined as gallic acid equivalents and total flavonoid contents were calculated as quercetin equivalents from a calibration curve. RESULTS: The leaf aqueous-ethanol extract showed the highest activity in DPPH radical scavenging activity. All extracts showed weak nitric oxide scavenging activity. The stem extract had better activity in nitric oxide scavenging model than the other extracts (IC50 = 896.9 +/- 21.9 microg ml(-1)), but it was not comparable to quercetin (p < 0.001). The leaf extract exhibited better H2O2 scavenging and Fe2+ chelating activity than the other parts. The extracts exhibited good antioxidant activity in linoleic acid peroxidation test but were not comparable to vitamin C (p < 0.001). Extracts showed weak reducing power activity. The stem extract showed better antihaemolytic activity than the flower and leaf. The flower extract had higher phenolic contents. The extracts exhibited different levels of antioxidant and antihaemolytic activities in all tested models. CONCLUSIONS: This study showed remarkable antioxidant and antihemolytic activities in Feruia foetida. Biological effects may be attributed to the presence of phenols and flavonoids in the extract. It is very promising for further biochemical experiments.

Pharmacological activities of Hypericum scabrum L.

OBJECTIVES: Hypericum spp. (H.) has been used in traditional medicine for their sedative effect for many years. In spite of many works on this genus, little is known about H. scabrum. In this work antidepressant and its protective effect against hypoxia-induced lethality were evaluated. MATERIALS AND METHODS: Antidepressant and its protective effects against hypoxia-induced lethality were evaluated. Antidepressant activity was determined by forced swimming test (FST) and tail suspension test (TST). Antihypoxic activities were determined by asphytic, haemic and circulatory hypoxia models in mice. Also, hydrogen peroxide scavenging activity and cumene hydroperoxide (CuOOH) induced hemolysis also were investigated. RESULTS: At all tested doses H. scabrum significantly and dose dependently reduced the immobility periods in FST and TST. Also, extract showed statistically significant antihypoxic activities in three asphytic, haemic and circulatory hypoxia models in mice. The extract showed moderately good scavenging activity with IC50 = 518.8 +/- 20.7 microg ml(-1). Extract inhibited significantly CuOOH induced hemolysis in red blood cells (RBC). CONCLUSIONS: H. scabrum aqueous extract showed remarkable antihypoxic and antidepressant effects thus, lend pharmacological justification to the use of the plant extract by traditional medicine practitioners. Mechanism of antidepressant activity of extract may be through nitric oxide pathway.

Antihemolytic and antioxidant activities of Biebersteinia multifida.

OBJECTIVES: Biebersteinia multifida is a common herb known in Iran. Its roots have been used locally in folk medicine of western region of Iran in the treatment of many diseases. The antioxidant activity and its inhibition of erythrocyte hemolysis were investigated. MATERIAL AND METHODS: 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), nitric oxide and hydrogen peroxide scavenging activities, Fe2+ chelating ability, reducing power and hemoglobin-induced linoleic acid peroxidation were used to evaluate antioxidant activities. Antihemolytic activity was evaluated by H2O2 induced hemolysis in rat erythrocyte. The total amount of phenolic compounds was determined as gallic acid equivalents and total flavonoid contents were calculated as quercetin equivalents from a calibration curve. RESULTS: Root had higher phenol contents (80.1 +/- 3.1 mg ml(-1)) and showed highest activity in DPPH radical-scavenging activity (95.9 +/- 3.2 microg ml(-1)). It also showed better reducing power than other parts. In Fe2+ chelating, leaf extract was the most potent (789 +/- 33 microg ml(-1)). Extracts exhibited good H2O2 scavenging in a concentration dependent manner. All extracts exhibited good protection against hemoglobin-catalyzed peroxidation linoleic acid system. In nitric oxide scavenging model, root extract showed the best activity (696 +/- 2.7 microg ml(-1)). Root and leaf extracts contained total phenol and flavonoids contents than other extracts. Tested extracts show weak activity in H2O2 induced hemolysis in rat erythrocyte which was not comparable with vitamin C. CONCLUSIONS: Biebersteinia multifida extracts exhibited different levels of antioxidant and antihemolytic activities in all tested models. Biological effects may be attributed, at least in part, to the presence of phenols and flavonoids in the extracts.

Protective role of Pleurotus porrigens (Angel's wings) against gentamicin-induced nephrotoxicty in mice.

OBJECTIVES: This study was conducted to quantitatively evaluate the recovery effects of methanolic fraction Angel's wings on gentamicin (GM)-induced nephrotoxicity. MATERIAL AND METHODS: Renal injury was achieved by injecting 100 mg/kg, intraperitoneally of GM in normal saline. Extract were administrated intraperitoneally at doses 200 and 400 mg/kg. Blood samples were examined for serum creatinine, serum urea, and blood urea nitrogen after the 10 consecutive days of treatment. RESULTS: Results show that GM-induced nephrotoxic animal model was successfully prepared. Methanolic fraction of Angel's wings attenuated the gentamicin-induced increase in level of serum creatinine, serum urea, and blood urea nitrogen. CONCLUSIONS: The present study shows that the extract at the doses 200 and 400 mg/kg, intraperitoneally offered significant nephroprotective action that is comparable with control group.

Antiinflammatory and antioxidant activities of gum mastic.

OBJECTIVES: Pistacia lentiscus has traditionally been used in the treatment of many diseases. Its resin was investigated for its mineral contents, anti-inflammatory and antioxidant activities in rats. MATERIAL AND METHODS: Inhibition of carrageenan induced edema was used to evaluate anti-inflammatory activity. Fe2+ chelating ability, 1,1-diphenyl-2-picryl hydrazyl radical (DPPH) and nitric oxide scavenging activities were used to evaluate antioxidant activities and mineral contents were determined by atomic absorption spectroscopy. Gallic acid content was determined by HPLC. RESULTS: Resin produced statistically significant inhibition of edema at all doses when compared to the control groups. A 100% inhibition of inflammation was observed at 800 mg/kg i.p. Resin exhibit no toxicity up to 3 g/kg body weights i.p. in mice. Weak DPPH and nitric oxide scavenging activities were observed but showed good Fe2+ chelating ability (IC50 = 162 microg ml(-1)). The amount of elements was decreased in the order: Cu > Fe, Zn > Mn > Ni, Cd. Gallic acid content was 0.1 mg/g resin. CONCLUSIONS: These experimental data support the use of Pistacia lentiscus resin as an antiinflammatory and antioxidant agent.

A novel method for automatic determination of different stages of multiple sclerosis lesions in brain MR FLAIR images.

It is very important to detect stages of multiple sclerosis (MS) lesions in order to exactly quantify involved voxels. In this paper, a novel method is proposed for automatic detection of different stages of MS lesions in the brain magnetic resonance (MR) images, in fluid attenuated inversion recovery (FLAIR) studies. In the proposed method, firstly, MS lesion voxels are segmented in FLAIR images based on adaptive mixtures method (AMM) and Markov Random Field (MRF) model. Then, signal intensity of each lesion voxel is modeled as a linear combination of signals related to the normal and also abnormal parts, in the voxel. By applying an optimal threshold, voxels with new intensities are primarily classified into two stages: previously destructed (chronic) and on going destruction (acute) lesions. Finally, the acute lesions, according to their activities, are classified, by another optimal threshold, into two new stages, early and recent acute. Evaluation of the proposed method was performed by manual segmentation of chronic and enhanced (early) acute lesions in gadolinium enhanced T1-weighted (Gad-E-T1-w) images by studying T1-weighted (T1-w) and T2-weighted (T2-w) images, using similarity criteria. The results showed a good correlation between the lesions segmented by the proposed method and by experts manually. Thus, the suggested method is useful to reduce the need for paramagnetic materials in contrast enhanced MR imaging which is a routine procedure for separation of acute and chronic lesions.

A Quantitative Investigation on the Effect of Edge Enhancement for Improving Visual Acuity at Different Levels of Contrast.

BACKGROUND: The major limitation in human vision is refractive error. Auxiliary equipment and methods for these people are not always available. In addition, limited range of accommodation in adult people when switching from a far point to a near point is not simply possible. In this paper, we are looking for solutions to use the facilities of digital image processing and displaying to improve visual acuity when using digital display devices. We quantitatively investigate the effect of edge enhancement on improving the visual acuity at different levels of contrast. We can improve visual acuity for people such as emmetropia, myopia and hyperopia when they utilize display devices. MATERIALS AND METHODS: According to the objective of this research, 24 visual acuity optical charts were designed using MATLAB software, based on logMAR standard. The charts have different levels of contrast with enhanced edges of optotypes at two brightness levels: 0 and 255. The proposed patterns were tested on 20 human subjects. The obtained results for each chart were analyzed in SPSS software. RESULTS: The results show that at all contrast levels, edge enhancement improves visual acuity. The degree of improvement where the edges have brightness level of 0 is higher than where the edges have brightness level of 255. CONCLUSION: Based on the results, enhancing the edges of optotypes in the background image improves visual acuity by about 16.1% on logMAR scale.