Antioxidative Properties of Crude Polysaccharides from Inonotus obliquus

The mushroom Inonotus obliquus has been widely used as a folk medicine in Russia, Poland and most of the Baltic countries. In this study, water-soluble and alkali-soluble crude polysaccharides (IOW and IOA) were isolated from I. obliquus, and the carbohydrate-rich fractions IOW-1 and IOA-1 were obtained respectively after deproteination and depigmentation. Their contents, such as neutral carbohydrate, uronic acid and protein, were measured. Their antioxidant properties against chemicals-induced reactive species (ROS) including 1,1'-Diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical and superoxide anion radical, as well as their protective effects on H(2)O(2)-induced PC12 cell death were investigated. Results showed that I. obliquus polysaccharides can scavenge all ROS tested above in a dose-dependent manner. IOA and its product IOA-1 could rescue PC12 cell viability from 38.6% to 79.8% and 83.0% at a concentration of 20μg/mL. Similarly, IOW and its product IOW-1 at the same dose, can also increase cell viability to 84.9% and 88.6% respectively. The antioxidative activities of water-soluble and alkali-soluble polysaccharide constituents from I. obliquus might contribute to diverse medicinal and nutritional values of this mushroom.     

Synthesis and Properties of a Ferrocene-based Metallomesogenic Polymer Containing Bis(4-hydroxyoctoxyphenyl)sulfone

Poly[bis(4-hydroxyoctoxyphenyl)sulfone 1,1′-ferrocene dicarboxylate] (PHOSFD) was synthesized by solution polycondensation reaction of bis(4-hydroxyoctoxyphenyl)sulfone with 1,1′-ferrocenyl chloride. The synthesized polymer was characterized via the measurement of its ¹H NMR spectrum, UV–Vis spectrum and FTIR spectrum. X-ray diffraction pattern was measured to investigate the crystallinity of the synthesized polymer and it was found that the polymer is mostly amorphous. The molecular weight of the polymer was determined by gel permeation chromatography. In addition, the electrochemical, the thermal, and the liquid crystalline properties of the synthesized polymer were examined and compared with the properties of poly(diethyleneglycol 1,1′-ferrocene dicarboxylate) (PDEFD) that was synthesized in our earlier study. The electrochemical processes of PHOSFD in CH₂Cl₂ were confirmed neither to be totally reversible nor completely irreversible. Generally, the electrochemical properties of PHOSFD and PDEFD were found to be similar to each other. PHOSFD was found to be thermally stable but its thermal stability is lower than that of PDEFD. Both of PHOSFD and PDEFD showed liquid crystalline properties and they possessed nematic phase textures with schlieren disclinations during heating and cooling.     

A review on operating parameters for optimum liquid oil yield in biomass pyrolysis

Pyrolysis is one of the potential routes to harness energy and useful chemicals from biomass. The major objective of biomass pyrolysis is to produce liquid fuel, which is easier to transport, store and can be an alternative to energy source. The yield and composition of pyrolysis oil depend upon biomass feedstock and operating parameters. It is often necessary to explore about the effect of variables on response yield and instinct about their optimization. This study reviews operating variables from existing literature on biomass pyrolysis. The major operating variables include final pyrolysis temperature, inert gas sweeping, residence times, rate of biomass heating, mineral matter, size of biomass particle and moisture contents of biomass. The scope of this paper is to review the influence of operating parameters on production of pyrolysis oil.     

Immediate release three-layered chewing gum tablets of fenoprofen calcium: preparation, optimization and bioavailability studies in healthy human volunteers

A three-layered gum tablet (1800 mg), containing 200 mg of Fenoprofen Calcium (Fn) with an inner core containing the drug, and two external layers containing antiadherent lubricant, has been prepared using direct compression. A 2(3) factorial plan has been designed to evaluate the effect of formulation variables namely, Pharmagum(?) M concentration, Maltodextrin type, and Co-adjuvant type on the release characteristics of Fn from the prepared tablets. The formula consisting of 65% Pharmagum(?) M, 75% Maltodextrin DE 39 and 5% Talc comparatively exhibited the highest release (66.59% ± 2.39) in the mouth after 5 min of chewing. Binary and ternary β-cyclodextrin (β-CD) complexation was adopted to enhance the release of Fn from the selected gum tablet. The highest significant release (p < 0.05) was achieved from the lyophilized ternary complex containing 100 mg of Fn in presence of polyvinylpyrrolidone (PVP K(25)), exhibiting a release of 88.25% ± 0.93 after 5 min of chewing. The relative bioavailability of the selected gum tablet was found to be 166.06% compared to Nalfon(?) 200 mg capsules. Reduction of the dose to 100 mg exhibited faster absorption rate than Nalfon(?) capsules. The obtained results suggest the possibility of reducing the dose of Fn in chewing gum.     

Survey of grid-connected photovoltaic inverters and related systems

Grid-connected photovoltaic (PV) inverter technology has advanced since it first attracted the attention of policy makers. The objective of this article is to present a survey of grid-connected PV inverters and their present technology in Malaysia. Surveyed here are 186 PV inverter products from 22 manufacturers, their power factors, system THDs, efficiencies, power inputs (from PV array), costs, sizes, and protections investigated, and their datasheets collected from various manufacturers in Europe, North America, and Asia. The data are compared within regions and subject headings. Discussed are the lowering of cost, the raising of efficiency levels, and reliability improvement.     

Designing and analyzing of a piezoelectric energy harvester with tunable system natural frequency for WSN and biosensing applications

A new structure for PEH with actuation piezoelectric layer for shifting natural frequency of the system is proposed. Beams are consisted to be Si and AlN piezoelectric which is deposited on fixed–fixed beams that produces high stress points and generates more power in comparison to the other cantilever beam PEHs. This PEH with ability of shifting system natural frequency is designed to the size of 0.25 cm² using optimum available space. Actuation piezoelectric layers added on both sides of the beams provides possibility of continues reducing systems natural frequency to less than 10 Hz. Accomplished simulation also confirms theoretical calculation done by PDE method to estimate natural frequency of the system. The natural frequency of the system without actuation voltage is 58 Hz that with 1 g acceleration generated 4.27 V and 71 µW electrical power which can be used in WSN and biosensing applications.

     

Application of Taguchi Method for Characterization of Corrosion Behavior of TiO2 Coating Prepared by Sol‐Gel Dipping Technique

Titanium oxide (TiO₂) nanoparticle coatings were deposited on the 316L stainless steel substrates by sol‐gel method. The morphology, structure, and corrosion resistance of the coating were analyzed using SEM, AFM, X‐ray diffraction, and electrochemical techniques. The deposition parameters employed to realize the anticorrosion performance including calcinations temperature, polyethylene glycol (PEG) content, pH value, and number of dipping cycles were investigated. Taguchi statistical experiments were carried out to determine the influence of the deposition variables on anticorrosion properties and optimal conditions. The results indicated that a higher anticorrosion performance of TiO₂ films could be achieved using 1 g of PEG in a sol with pH in range of 7–9, six cycles of dipping, and calcination temperature at 400°C. The Tafel polarization measurements indicate that i_corr value decreases about 200 times and the R_corr value increases around 57 times compared with uncoated 316L stainless steel.     

Effect of Nanoparticles on Mechanical and Flame-retardant Properties of Polyether-Block-Polyamide Polymer Nanocomposites

In this study, polyester elastomer-based thermoplastic (TPEE) nanocomposites were fabricated for flame-retardant applications. Small amounts of graphene and nanoclay were added to the nanocomposites to investigate their effects on the mechanical and thermal properties of the nanocomposites. The addition of a phosphorous flame-retardant additive resulted in a significant improvement of the Young’s modulus and thus yield stress in the synthesized nanocomposites as compared to those made with the virgin TPEE. There was no synergistic improvement in mechanical properties with the addition of graphene and nanoclay to the nanocomposites. However, thermal properties, mainly the heat deflection temperature and fire performance (UL-94 V0), were improved significantly by the addition of graphene and nanoclay and a synergistic effect was observed. Heat distortion temperature and thermogravimetric analysis were used to analyze the thermal properties of the nanocomposites. The UL-94 testing method was used to investigate the fire performance of the nanocomposites. Scanning electron microscopy was used to observe the polymer fracture surface morphology. The dispersion of the graphene and nanoclay particles was confirmed by transmission electron microscopy analysis.     

Large-scale group decision-making (LSGDM) for performance measurement of healthcare construction projects: Ordinal Priority Approach

People with various skill sets and backgrounds are usually found working on projects and thus, group decision-making (GDM) is one of the most important functions within any project. However, when projects concern healthcare or other critical services for proletariat or general public (especially during COVID19), the importance of GDM can hardly be overstated. Measuring the performance of healthcare construction projects is a critical activity and should be gauged based on the input from a large number of stakeholders. Such problems are usually recognized as large-scale group decision-making (LSGDM). In the current study, we aim to propose a decision support system for measuring the performance of healthcare construction projects against a large number of experts using ordinal data. The study identifies several key indicators from literature and recorded the observations of a large number of experts about these indicators. After that, the acceptable range of complexity is specified, the Silhouette plot is provided to find the optimal number of clusters, and the ordinal K-means method is employed to cluster the experts’ opinions. Later, the confidence level is measured using a novel Weighted Kendall’s W for the optimal number of the clusters, and the threshold is checked. Finally, the conventional problem is solved using the Group Weighted Ordinal Priority Approach (GWOPA) model in multiple attributes decision making (MADM), and the performance of the projects is determined. The validity of the proposed approach is confirmed through a comparative analysis. Also, a real-world case is solved, and the performance of some healthcare construction projects in China is gauged with a comprehensive sensitivity analysis.