Objective(s): Quince seed mucilage (QSM) serves as a new source of hydrocolloid which extracted from outer pericarp of Cydonia oblonga seeds upon wetting. It has been traditionally used for the treatment of diseases such as pharyngeal disorder, common cold, colic ulcer, and diarrhea. The aim of the present study was to evaluate the physico-mechanical and antimicrobial properties of quince seed mucilage supplemented with titanium dioxide (TiO2) and Silicon dioxide (SiO2) nanoparticles. Methods: The antimicrobial property of designated QSM against Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Listeria monocytogenes, Salmonella typhimurium, and Escherichia coli O157: H7 was determined using agar disk diffusion and broth micro-dilution assays. Thickness, tensile strength (TS), puncture force (PF), puncture deformation (PD), swelling index (SI), and color of active QSMs were evaluated using analytical instruments. Results: The films containing TiO2 and SiO2 nanoparticles exhibited good antimicrobial effects against S. aureus, B. subtilis, B. cereus, L. monocytogenes, S. typhimurium, and E. coli O157: H7 ranged 0. 82-6. 88 mm and-2. 78--0. 28 log differences in population (DP) regarding agar disk diffusion and broth microdilution assays, respectively. The presented values, including TS, PF, and PD of QSM films, were in the ranges of 22. 45-35. 81 MPa, 10. 42-15. 49 N, and 15. 53-18. 45 mm, respectively. Conclusions: Application of TiO2 and SiO2 nanoparticles greatly improved the antimicrobial and physico-mechanical properties of the prepared films.

Background and Objectives: Heavy metals such as cadmium causing numerous adverse effects on the aqueous solutions. So the presence of heavy metals in surface water and ground water has become a major inorganic contamination problem. There are several method to remove the heavy metals from aqueous solutions that adsorption is one of the best method. The aim of this study was to evaluate the efficiency of Silicon dioxide nanoparticles modified by 2-aminopyridin and EDTA as adsorbent for the removal of Cd2+ ions from aqueous solutions. Materials and Methods: Silicon dioxide nanoparticles with toluene put in ultrasonic bath. Then mixture of 2-aminopyridin and EDTA with ratio of 1: 1 added to primary solution. After 24 hours reflux on oil bath and 10 minutes centrifuging, sample rinsed by chloroform, ethanol and deionized water. In the end, the product prepared after drying at 100 oC for 24 hours. Experiments were conducted to study the effect of solution pH, temperature, contact time, absorbent amount and initial metal concentration. Experiment conducted in bath system with three replicate. The test solutions of various concentrations were prepared from the stock solution. The solution pH was adjust using 0. 1 M HNO3 and 0. 1 M NaOH at the beginning of the experiment and not controlled afterwards. Solution containing adsorbate and adsorbent was taken in 250 mL capacity conical flask and agitated at 120 rpm in a shaker at predetermined time intervals. Samples putted on the centrifuge with 4000 rpm for 5 minutes. Lead ions were determined spectrophotometrically by atomic absorption spectrophotometer. Finally for determination of adsorption mechanism, adsorption isotherm models and kinetic models were studied. Results was analyzed by Excel software. Results: The Results showed that, the highest uptake and optimum conditions was observed in pH=4, contact time 35 minutes and temperature 25 oC. The Analysis of Langmuir isotherm (R2=0. 93) and Freundlich isotherm (R2=0. 94) show that, experimental data were fitting match by both isotherm but it is more fitting match with Freundlich isotherm. Kinetic studies showed that, kinetic of adsorption according to pseudo second order equation (R2=0. 99). Conclusion: Base on the results it can conclude that, modified silicon dioxide nanoparticles could be used as a best adsorbent for the removal of heavy metals from aqueous solutions especially for the industrial wastewaters because of the cost, easy to use, renewable, suitable and environmental friendly. Comparing with other similar studies these were found to be the excellent adsorbents and can be successfully used by Industries for heavy metal removal.

Osteoarthritis (OA) is the most common type of arthritis and although there is no definitive cure for it, there are treatments for symptom management. The present study was conducted to evaluate the effects of silicon dioxide (SiO2) on clinical symptoms of knee OA and compare it with avocado soybean unsaponifiable (ASU) and placebo. This study is a double-blind randomized clinical trial on 104 patients with knee OA referred to Rheumatology Clinic, Rasoul Akram Hospital, Tehran. Patients were randomly divided into three groups, including patients treated with ASU, SiO2, and placebo for 3 months. Subsequent referral was performed at weeks 4, 8, and 12, and the stiffness, physical function, and pain scores were recorded based on the WOMAC questionnaire. In this study, the effect of treatment of placebo and SiO2 and ASU in patients with knee OA based on WOMAC questionnaire showed a significant reduction in terms of pain, joint stiffness, physical function, and total scores of WOMAC in the cases of the SiO2 group compared with the other two groups. The findings of this study showed that the therapeutic effects of SiO2 in patients with knee OA in terms of pain and stiffness and physical function scores were more than the ASU and placebo groups.

Objective: Silicon has beneficial effects on a wide range of plant species under abiotic stresses. For this reason, investigating the role of silicon in improving the growth of crops under stress has always been of interest.Methods: This study aimed to investigate the effect of silicon dioxide on seedlings of bread wheat, Pishtaz cultivar. After sterilizing wheat seeds with 70% ethanol, the seeds were planted in pots filled with perlite. The experiment was arranged as factorial based on a randomized complete block design. At the two-leaf stage, silicon dioxide was applied at four levels (0, 15, 30, and 45 mg/l). After one week, salinity stress was applied at two levels of 0 and 100 mM. After one week of applying salt stress, different morphophysiological traits including root and shoot length, root and shoot fresh and dry weight, and content of chlorophyll a, b, carotenoids, sodium, potassium, and iron were measured.Results: The results showed that salinity has a negative effect on morphophysiological traits, and on the contrary, silicon, especially at a concentration of 45 mg/liter, improves these traits under salt stress. Also, the sodium content in the presence of silicon decreased strongly in the wheat seedlings under salinity, and on the contrary, the K/Na increased. Silicon also had a positive effect on the content of iron and chlorophyll of seedlings under salt stress.Conclusion: These results show that silicon improves the growth of bread wheat seedlings by facilitating the absorption of mineral elements, homeostasis of nutrients, and preventing the destruction of chlorophyll.

The X-ray fluorescence spectrometry and the MA. BM. 006 reference spectrophotometric methods were used to determine the content of SiO2 (%) in bauxites from different deposits. The treatment of samples prior to the analysis involved the following steps: annealing, melting using the borax method, and the formation of beads. Certified reference bauxite samples were used for the calibration curve. The calibration curve was produced with the correlation coefficient of r =0. 9999 and the standard error of S = 0. 0246. The average residual value between the content of SiO2 determined using the XRF method, and the reference method was 0. 045, with a standard deviation of 0. 068. The XRF method was statistically verified by the F-and t-tests (using the standard sample and the reference method). The values obtained in the tests show that the XRF method yields accurate results and that there are no standard errors.

Silicon dioxide (SiO2) in nanoscale had been detected as waste product in river water for the past two decades and it is recently proven to have adverse effects toward human and animal health, the ecosystem and water treatment system. The removal of SiO2 nanoparticles (NPs) from water still remains a challenge due to its small size and unknown interactions within the water body. In this study, dynamic light scattering (DLS) technique was applied to characterize SiO2 in terms of surface charge and particle size as a function of pH within the range of 2 to 11 to analyze the aggregation behavior and significance of the intermolacular interactions in deionized (DI) water and tap water. DLS analysis identified both pH values of the point of zero charge (pHPZC) of SiO2 NPs in DI water and tap water at pH 3. 2 and pH 2. 8 respectively. The initial pH was discovered at 7. 1 in tap water with a mean particle size of 346 nm and an average surface charge value of-27 mV compared to initial pH of DI water which was 5. 4 with mean particle size of 295 nm and an average surface charge value of-33 mV. It was found that both in DI water and tap water, SiO2 NPs aggregated and increased in particle size but reduced in surface charge when pH slowly decreased towards their respective pHPZC from the initial pH by adding 0. 25M of hydrochloric acid. The mean particle size at pHPZC in DI water is measured at 1750 nm larger compared to the mean particle size in tap water indicating that the presence of other ions in tap water suppressed the aggregation process. In conclusion, results suggests that pH does influence the surface charge of SiO2 NPs and affect the stability behavior and its interaction processes in aqueous suspensions.

Objective(s): Due to nanocomposites antimicrobial properties, one of the most extensive usages of nano-products is in packing industry. Thus, the production of packages with nanotechnology can effectively prevent against a variety of microorganisms.In this study, the silicon dioxide nanoparticles the poly (lactic acid) PLA films on antimicrobial and permeability was investigated.Methods: In order to measure the effect of antibacterial nano-covers, the direct contact of 1%, 3% and 5% silicon dioxide nanoparticles was used. Furthermore, the sample was contaminated with standard strains of gram-negative (Escherichia coli–code of 1399 (ATCC 25992)) and bacteria gram-positive (Staphylococcus aureus–code of 1431 (ATCC 25923)) provided. Diameters of inhibition zones were measured after 24 h incubation of plates at 37 °C, by using Digital Caliper. Also, the water vapor permeability was investigated according to ASTM E96 and oxygen standards according to ASTM D 3985 standard from film surface.Results: Comparison the mean diameter of the inhibition zone of Escherichia coli, PLA containing 3% silicon dioxide with PLA film containing 5% silica showed no significant difference between the two groups (P>0.05) as well as, the average diameter of Staphylococcusaureus (P>0.05). The results showed that the permeability compared to water vapor and oxygen vapor in pure PLA films with PLA containing 1%, 3% and 5% silicon dioxide showed a significant difference (P<0.05).Conclusion: PLA /nanocomposite SiO2 films have been identified as the most efficient cover in reducing the microbial load and have been useful as active antimicrobial nanopackaging.