Thin natural gelatin/chitosan nanofibrous scaffolds for retinal pigment epithelium cells

Damage of the retinal pigmented epithelial cells causes various diseases such as age-related macular degeneration in retinal tissue. Nowadays, scientists are attempting to replace lost retinal cells with healthy and efficient cells that provide better conditions for recovering and preventing blindness. In this study, gelatin/chitosan nanofibrous scaffolds with mean diameters of 180?nm were fabricated for subretinal space through electrospinning. Thickness and morphology of the gelatin–chitosan scaffolds were analyzed by scanning electron microscopy (SEM). The results showed that the high rate of degradation, i.e., 90% damage was obtained after 1 month. The cell viability of gelatin/chitosan nanofibers were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The SEM results of cultured RPE on gelatin/chitosan scaffolds showed the appropriate adhesion of cells on the substrate. The results of the identity of RPE cells cultured on the scaffolds indicated that a large number of cells strongly expressed RPE65 and cytokeratin 8/18.     

Soluble soybean polysaccharide/TiO2 nanocomposites: Biological activity,release behavior,biodegradability, and biosafety

This study aimed to produce and characterize eco-friendly SSPS nanocomposites incorporated with various concentrations of TiO₂ nanoparticles (NPs) (1%, 3%, and 7%). The antimicrobial activity of the nanocomposite films against five strains of pathogenic bacteria was examined. Salmonella typhi PTCC 1609 was the most sensitive species to TiO₂ NPs at concentrations equal to the synthetic antibiotic. The migration of TiO₂ to ethanol and acetic acid, as two food simulants increased when the initial nano-TiO₂ content increased. The release profiles for TiO₂ in two simulants of ethanol and acetic acid indicated a non-Fickian release, and the release kinetics were concentration-dependent. SSPS/TiO₂ nanocomposites degraded easily and thus have the potential to be applied as an eco-friendly packaging system. Oral administration of doses of 1, 12.5, 25, 50, and 75 mg/kg TiO₂ revealed that the dose of 50 and 75 mg/kg increased malondialdehyde (p < .001) concentration in the liver tissue. In addition, it decreased glutathione (p < .001) concentration in the liver tissue.     

A new solution method for stochastic differential equations via collocation approach

The objective of this paper is to propose a novel solution method for Itô stochastic differential equations (SDEs). It is discussed that how the SDEs could numerically be solved as matrix problems. To improve the accuracy of this technique in contrast to the existing solvers, some non-uniform grids of points for discretizations along the time direction are applied. Finally, the high accuracy of approximated solutions in this way are illustrated by several experiments.     

Pan-heating of low-linolenic acid and partially hydrogenated soybean oils

Genetically modified low-linolenic acid soybean oil (LL-SBO) was compared to partially hydrogenated soybean oil (PH-SBO). Samples were heated on a Teflon pan at ∼180°C until a selected end point of ≥20% polymer content was reached. High-performance size-exclusion chromatography analysis indicated the PH-SBO contained >20% polymer after 20 min of heating, whereas the LL-SBO sample contained >20% polymer after 10 min. Supercritical fluid chromatography analysis indicated degradation rates of 0.161±0.011 min⁻¹ for LL-SBO and 0.086±0.004 min⁻¹ for PH-SBO. The volatile compounds were identified and quantitated with static head-space-GC-MS. 1-Heptene (239.9 ppm) and hexanal (1486.1 ppm) were present at the greates concentration among the volatile compounds in LL-SBO. The volatile compounds present in the greatest concentrations in heated PH-SBO were hexanal (376.9 ppm) and pentane (82.1 ppm). After 10 min of heating, the LL-SBO oil FFA value (2.66%), p-anisidine value (386.5 abs/g oil), Food Oil Sensor reading (18.75), and color intensity (Y=4.0, R=1.0) were significantly greater than those of PH-SBO after 14 min of heating (4.28%, 298.5 abs/g oil, 16.08, Y=1.0, R=0.1, respectively). There was a significant difference in the degradation rates between LL-SBO and PH-SBO (P<0.05). The PH-SBO was more stable than the LL-SBO.     

Trend Detection of Drought in Arid and Semi-Arid Regions of Iran Based on Implementation of Reconnaissance Drought Index (RDI) and Application of Non-Parametrical Statistical Method

Drought is known as one of the main natural hazards especially in arid and semi-arid regions where there are considerable issues in regard to water resources management. Also, climate changes has been introduced as a global concern and therefore, under conditions of climate change and global warming, the investigation of drought severity trend in regions such as Iran which is mainly covered by arid and semi-arid climate conditions is in the primary of importance. Therefore, in this study, based on the application of Reconnaissance Drought Index (RDI) for assessment drought severities, and also the implementation of non-parametric Mann- Kendall statistics and Sen’s slope estimator, the trends in different time series of RDI (3, 6, 9, 12, 18 and 24 monthly time series) were investigated. Results indicated the frequent decreasing trends in RDI time series particularly for long term time series (12, 18 and 24 monthly time series) than short term ones. Decreasing trend in RDI time series means the increasing trend in drought severities. Since the water resources especially ground water in most cases are affected by long term droughts, therefore, increasing trend in drought intensities in long term ones can be a threat for water resources management in surveyed areas.     

Comparison of a low-linolenic and a partially hydrogenated soybean oil using pan-fried hash browns

Hash browns (HB) were fried (Teflon-coated pan, ∼180°C) with low-linolenic acid (LL-SBO) and creamy partially hydrogenated soybean oils (PH-SBO). High-performance size-exclusion chromatography of the oil extracted before heating indicated a relatively low polymer content (LL-SBO, 3.8%; PH-SBO, 1.6%), although the oil remaining in the pan after frying had a much greater polymer content (38.8%, LL-SBO; 17.5%, PH-SBO). The percentage of altered TAG in the LL-SBO sample (extracted from HB) was 34.4% after frying, whereas the PH-SBO had 33.2% altered TAG (as determined by supercritical fluid chromatography). In the LL-SBO pan-fried HB samples (not the extracted oil), 2-pentanone, hexanal, 2-hexenal, trans-2-heptenal, 2-pentylfuran, and trans-2-octenal were found, whereas the major volatile compounds in the HB fried with PH-SBO included hexanal, trans-2-hexenal, and trans-2-heptenal. Hexanal was the most abundant volatile compound in both HB samples (LL-SBO, 2.7 ppm; PH-SBO, 0.3 ppm). There were significant differences in the polymer content, hexanal content, p-anisidine values, and Foodoil sensor readings between LL-SBO and PH-SBO (P<0.05). The PH-SBO sample was more stable than the LL-SBO sample. Moreover, the LL-SBO oil sample in the pan after frying had the greater increase in polymer content.     

A modified model reference adaptive control with application to MEMS gyroscope

Micro electro-mechanical systems (MEMS) are increasingly being used in measurement and control problems due to their small size, low cost, and low power consumption. The vibrating gyroscope is a MEMS device that will have a significant impact on stability control systems in the transportation industry. This paper investigates the application of a modified model reference adaptive control for MEMS gyroscope. Using this adaptive control algorithm, an estimation of the angular velocity and the damping and stiffness coefficients in real time is easily computable. Changing the conventional model reference input makes it feasible to utilize a low pass filter to remove unwanted oscillations caused by high adaptation gain. This new adaptive control technique enables quick compensation for large changes in the system dynamics, providing consistent estimation of gyroscope parameters including angular velocity and large robustness to parameter variations and external disturbances. The asymptotic stability of the mentioned adaptive controller is guaranteed using the Lyapunov direct method. Numerical simulation is presented to verify the effectiveness of the proposed control scheme.     

Application of variational mesh generation approach for selecting centers of radial basis functions collocation method

In this paper, a two-dimensional variational mesh generation method is applied to obtain adaptive centers for radial basis functions (RBFs). At first, a set of uniform centers is distributed in the domain, then mesh generation differential equations are used to move the centers to region with high gradients. An iterative algorithm is introduced to solve steady-state mesh generation differential equations with RBFs. Functions with steep variation in the domains are used to validate the adaptive centers generation method. In addition to the centers adaption process is applied to solve elliptic partial differential equations via RBFs collocation method. Numerical results of Helmholtz differential equation show a clear reduction in the error, when the adaptive centers are used for RBFs.     

A new hybrid denoising model based on PDEs

In this paper, a novel denoising algorithm based on the denoising methods of partial differential equations is presented. The proposed algorithm is obtained by using a stochastic algorithm for combining two denoising methods based on partial differential equations. The model provides a new approach for solving the contradiction in the image restoration. The new hybrid model has more ability to restore the image in terms of peak signal to noise ratio, blind/referenceless image spatial quality evaluator and visual quality, compared with each of denoising methods separately used. Experimental results show that our approach is more efficient in image denoising than the used denoising methods.     

Deacidification of Soybean Oil Using Membrane Processing and Subcritical Carbon Dioxide

Vegetable oils have been deacidified using supercritical carbon dioxide and membrane processing. However, the pressures required are substantially greater than those used in industry. Therefore, the feasibility of using subcritical carbon dioxide (at much lower pressures) and membrane processing to separate free fatty acids (FFA) from triacylglycerols (TAGs) was examined. First, FFA/TAG solubility tests were completed (10–25 °C and 68–136 atm). The oil samples were separated using a FilmTec NF90 or a FilmTec BW30 membrane in a dead-end type cell. Within the range examined, the greatest solubility for oleic acid was at 25 °C and 136 atm. For soybean oil TAGs, the greatest solubility was at 20 °C and 136 atm. However, for the separation of the two components, 20 °C and 68 atm was best among the condition combinations examined. The solubility of oleic acid ranged from 0.294 to 0.455 mg/mL in subcritical carbon dioxide, while the solubility of triacylglycerols ranged from 0.066 to 0.139 mg/mL. The FilmTec BW30 membrane provided significantly better separation of FFAs from TAGs than did the NF90 membrane. Both membranes were selective for oleic acid, although the BW30 had greater selectivity for oleic acid (β _{oleic acid} = 2.12, β _TAGs = 0.24) than the NF90 membrane (β _{oleic acid} = 1.26, β _TAGs = 0.81).