Current Approaches in Improving Hemocompatibility of Polymeric Membranes for Biomedical Application

Suitable membranes for blood‐contacting medical applications need to be resistant in confrontation with blood proteins and cells, while possessing high blood compatibility and permeability at the same time. Herein, an overview of the recent advances and strategies that have been used to enhance the hemocompatibility of polymeric membranes is provided. The review focuses on two modification strategies: (i) physical modifications and (ii) chemical modifications. It also highlights the current progress in the design of hemocompatible‐functionalized membranes for biomedical applications. Subsequently, the commonly applied biocompatibility tests are also discussed and finally the future perspectives of the application of polymeric membranes in the biomedical field are presented.

     

A study on siro,solo, compact,and conventional ring-spun yarns. Part III: modeling fiber migration using modular adaptive neuro-fuzzy inference system

The importance of fiber migration in spun yarns as a means of securing cohesion and strength has been emphasized in the literature. However, analyzing migration behavior of fibers is a time-consuming and tedious task. A three-stage hybrid model was developed to estimate yarn migratory properties based on some physical and mechanical properties of spun yarns. Achieving the objectives of this research, general physical, mechanical, and structural properties of spun yarns together with existing standards were thoroughly studied. At the first stage, using stepwise regression analysis, key variables were selected. At the second stage, data-set was clustered into subpopulations by means of K-means in order to decrease effects of noise, rebate complexity of the patterns, and develop a modular model. At the third stage, using adaptive neuro-fuzzy inference system, the target value was predicted. Finally, evaluation of the proposed model was carried out by applying it on the test set.     

Effects of Different Boron Compounds on the Corrosion Resistance of Andalusite-Based Low-Cement Castables in Contact with Molten Al Alloy

Interfacial reactions between Al alloy and andalusite low-cement castables (LCCs) containing 5 wt pct B₂O₃, B₄C, and BN were analyzed at 1123 K and 1433 K (850 °C and 1160 °C) using the Alcoa cup test. The results showed that the addition of boron-containing materials led to the formation of aluminoborate (9Al₂O₃.2B₂O₃) and glassy phase containing boron in the prefiring temperature (1373 K [1100 °C]), which consequently improved the corrosion resistance of the refractories. The high heat of formation of the aluminoborate phase (which increased its stability to reactions with molten Al alloy) and the low solubility of boron in molten Al were the major factors that contributed to the improvement in the corrosion resistance of B-doped samples.     

Preparation of mullite from alumina/aluminum nitrate and kaolin clay through spark plasma sintering process

In the present study, the in-situ synthesized mullite has been prepared successfully by mixing kaolinite with alumina and aluminum nitrate nonahydrate (ANN) powders through high energy milling followed by spark plasma sintering (SPS). Using a high-energy ball-mill, the stoichiometric compositions of the starting powders, considering their final transformation to Al₂O₃ and SiO₂, have been mixed. The SPS process has been performed at 1400 and 1375?°C for the specimens containing Al₂O₃ and ANN, respectively. XRD patterns of the milled powders after 30?h showed the formation of quartz from kaolinite for both starting batches. The displacement-temperature-time (DTT) curves and the corresponded vacuum changes indicated the dehydration and phase transformation of ANN and kaolinite at different stages of the sintering process. The XRD patterns of the sintered samples revealed the formation of mullite alongside un-reacted Al₂O₃ and crystobalite for the batches containing Al₂O₃ and ANN, respectively. The results of the physical and mechanical properties tests showed higher amounts of bending strength (397?±?18?MPa), Vickers hardness (16.32?±?0.21?GPa) and fracture toughness (3.81?±?0.24?MPa?m^?1/2) alongside a lower porosity (0.070?±?0.02%) for the prepared sample containing Al₂O₃, than those of the sample containing ANN.     

Preparation mullite/Si3N4 composites by reaction spark plasma sintering and their characterization

In the present study, in-situ mullite/Si₃N₄ composites were prepared successfully by reaction spark plasma sintering. For this purpose, 5, 10 and 15?wt% of Si₃N₄ were added to stoichiometric mullite made of mechanically milled mixture of alumina and kaolin clay to investigate the effect of reinforcement content on the final properties of the prepared composites. The sintering processes were performed at 1400?°C under the initial and final applied pressures of 10 and 30?MPa and the vacuum condition of 17?Pa. The XRD patterns revealed the mullite and Si₃N₄ peaks as the dominant crystalline phases. Microstructural investigations demonstrated a uniform distribution of Si₃N₄ inside mullite matrix for the composites containing 5 and 10?wt% of the reinforcement particles. Meanwhile, some agglomerates of Si₃N₄ were observed in the microstructure of the mullite-15?wt%Si₃N₄ composite. Moreover, no evidence of reaction between the starting materials was detected through XRD and FESEM analyses. The highest values of hardness, bending strength, and fracture toughness obtained for the composite containing 15?wt% of Si₃N₄ were 19.14?GPa, 481?MPa and 3.85?MPa?m^?1/2, respectively. The fracture toughness mechanisms were detected as crack branching, breaking and deflection, as well as particles pulling-out, all of which were observed in the mullite-15?wt%Si₃N₄ composite.     

Inspection interval optimization for complex equipment in automotive manufacturing under dependent failures

Forschung im Ingenieurwesen - Inspection activities in automotive manufacturing play a crucial role in diagnosing and preventing unexpected failures by adopting the well-planned intervals....     

A new method for layer 2 loop prevention in software defined networks

Telecommunication Systems - Broadcast storm refers to the bandwidth saturation caused by broadcast traffic flows when a loop exists and it can quickly lead to the network failure. In legacy...     

Dry reforming of methane over nano-Mo2C/Al2O3 catalyst: Effect of carburization conditions on excess carbon deposition

In this study, temperature-programmed carburization (TPC) has been used to prepare Mo₂C/Al₂O₃ catalyst for carbon dioxide reforming of methane. Also, the effect of carburization conditions has been examined on excess carbon formation over the prepared catalysts. Minimum excess carbon of 0.51 wt% was obtained in a flow of 12.5 vol% CH₄/H₂ gas mixture, final carburization temperature of 750°C, and Mo loading of 12.5 wt%. This catalyst exhibited better initial activity due to lower excess carbon and higher carbide dispersion compared with other examined catalysts. However, the results of time on stream performance in the dry reforming of methane (DRM) revealed an increase in durability with an increase in Mo loading.     

Quantitation of limonin in Iranian orange juice concentrates using high-performance liquid chromatography and spectrophotometric methods

Bitterness is a major problem in the citrus industry worldwide, and is mostly due to the presence of limonoid compounds, especially limonin. In this study, the limonin content of orange juice concentrates from three active factories in west Mazandaran province, after reconstitution, was assayed using high-performance liquid chromatography (HPLC) and spectrophotometric methods. With HPLC, employing acetonitrile/water (v/v) (32:68) with a flow rate of 0.9 ml/min at =207 nm, the limonin content was in the range 11.7–23.3 g/ml with a mean ± standard deviation (SD) of 18.5±3.6 g/ml. Spectrophotometric measurement of limonin at 503 nm with Burnham reagent gave a range of 9.9–21.8 g/ml with a mean ± SD of 17.16±4.1 g/ml. The correlation coefficients of the detector linear response for the limonin standard (0–50 g/ml) for HPLC and spectrophotometry were 0.995 and 0.989, respectively. The percentages of limonin recovery with and without sample addition were 101.02–111.40 and 93.0–100.8, respectively, for HPLC. The percentages of limonin recovery for the spectrophotometric method resulted in 95.6–101.8 for limonin-added samples. The precision factors for the two assay methods were ±2.10% and ±1.69, respectively. The correlation coefficient of the two methods was 0.84. Sensory evaluation of the reconstituted samples from the view point of bitterness confirmed 85% of the results of the analytical methods. This study recommends spectrophotometric analysis as a useful and suitable method for quantitation of limonin in the quality control laboratories of orange juice plants.     

An Evolutionary Game-Theoretic Approach for Base Station Allocation in Wireless Femtocell Networks

Wireless Personal Communications - A set of moving nodes communicating with each other without any infrastructure is considered a mobile ad hoc network (MANET). Stability is a big problem with this...