Applied Mechanics and Materials Vol. 472

Abstract: Biodiesel from mungongo seeds oil (Schinziophyton rautanenii) was investigated in the present study to determine its suitability for use as substitute of petro diesel. The fuel properties of Mungongo Oil Methyl ester (MOME) such as cetane number, kinematic viscosity, oxidative stability, lubricity, cloud point, pour point, cold filter plugging point, flash point, acid value, density, higher heating value, free and total glycerol were determined and compared with global biodiesel standards such as ASTM 6751 and EN 14214. Most of the determined fuel related properties of MOME fulfilled the minimum requirements of ASTM D6751 and EN 14214 biodiesel standards except oxidation stability. The stability of biodiesel is very critical and biodiesel requires antioxidant to meet storage requirements and to ensure fuel quality at all points along the distribution chain. Therefore, three antioxidants; 1, 2, 3 tri-hydroxy benzene (Pyrogallol, PY), 3, 4, 5-tri hydroxy benzoic acid (Propyl Gallate, PG) and 2-tert butyl-4-methoxy phenol (Butylated Hydroxyanisole, BHA) were investigated. The result showed that, PY and PG were more effective antioxidants than BHA.

Abstract: Several Eucalyptus cultivars has been introduced and cultivated for millions of hectares afforestation in subtropical China, whose woods were mainly used in papermaking industry and whose water essential oils were used mainly in aroma and medical industry. However, the potential biomedical components of organic essential oils were still uncovered. In order to reveal constituent characteristic and biomedical potentials of organic essential oils from leaves of four Eucalyptus cultivars (E. camaldulensis, E. tereticornis, E. citriodora and E. dunnii) in China, their components were efficiently extracted by improved solvents extracting condition, which were identified by optimal gas chromatography / mass spectrometry (GC/MS). The functional analytical results suggested that these four Eucalyptus cultivars possess large numbers of common components, especially including Eucalyptol, 1-Eicosanol, (+)-Longifolene, (+)-Aromadendrene, Phytol and (-)-Alloaromadendrene, which are good materials for aroma and biomedical industry. The contents of common components of four Eucalyptus cultivars are as high as 68.97%, 81.81%, 60.64% and 64.29%, respectively. Moreover, each Eucalyptus organic essential oil also has specific components with potentials in aroma industry or biomedical industry.

Abstract: To research ultrastructure changes of rat skeletal muscle in the process of repetition eccentric exercise, Wistar rats were divided into normal control group, one eccentric exercise group, repeated eccentric exercise group. The ultrastructure and proteome changes made by downhill run and repetitive downhill run after a week in rats were observed in instant, 24h, 48h, 72h and 168h after one and repeated bout of exercise rats. The results showed that the most serious injuries of sarcomere in 48 hours after exercise, sarcomere disordered or disappeared, Z-line fractured and myofilament decomposed. From 24h to 48h, mitochondria was severely damaged, which structure gradually restored within 72 hours, the muscle fiber reconstructed, but mitochondrial number, structure and function had not yet been fully restored, the muscle cells in aerobic capacity have not yet fully been restored. At the same time, the injury severity of repeated exercise group was palliative compared to that of the first exercise, which may be related to recovery rate of mitochondrial damage. Therefore, repetitive motion can change the mitochondria's own repair speed, stimulate muscle to adapt the density of exercise, and reduce the extent of skeletal muscle micro-injury. Repeated eccentric exercise may promote key enzyme expression of energy metabolism and energy supply for damage cell, accelerate skeletal muscle contraction protein degradation and cell swallow, and scavenge free radicals and slow inflammatory reaction during 24-48h to speed up the skeletal muscle damage repair. Keywords: Eccentric Exercise, Repetitive Exercise, Skeletal Muscle, Ultrastructure, Peoteome

Abstract: The Zanthoxylum avicennae 95% EtoH extracts after concentration were dissolved in H₂O and extracted with EtoAc and n-BuOH Successively. The n-BuOH layer was added to Diaion HP-20 macroporous resin column, then the resin was washed by distilled water to get rid of impurity, then washed by 20%, 40% and 60% methanol individually, and obtained M₂₀, M₄₀ and M₆₀ respectively. And antioxidant activity was assessed using three methods: DPPH radical-scavenging activity, ABTS⁺ radical-scavenging activity, ferric reducing antioxidant power (FRAP) assay. The results indicate that TEAC value of M₄₀ were higher than other part extracted from Zanthoxylum avicennae 95% EtoH extracts during three methods .The results of the experiments also can find M₄₀ is the strongest antioxidant activity part in Zanthoxylum avicennae 95% EtoH extracts and provide reference for further isolating the part M₄₀.

Abstract: The paper is to study the mechanism of antioxidation-endocrine-immune network through exercise with rice after PM_2.5 been exposed. The 40 male Wistar SPF rats were randomly divided into the QC, EC, LPE, MPE, HPE. the serum GSTs, T-AOC, GSH-Px, NE, T, C, FT, TNF-α, IL-1β were tested.The results showed that the activity of GST, C, NE, IL-1β have upward trend but the T-AOC, GSH-Px and T declined compared with the QC; compared with the EC group, all PM_2.5 exposed+exerxise have the same upward oe downward trend compared with EC. Conclusion: PM_2.5 exposure can destroy the antioxidant and immune defence, it has dose-response ralationships with the PM_2.5 doses concentration; the negtive influence of PM_2.5 to antioxidation-endocrine-immune network may be one of the mechanism of sports ability decline in the air pollution environment.

Abstract: SPI/PVA films were successfully prepared with complex plasticizers containing urea and trethanolamin (TEA) by casting and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), ultraviolet (Uv-vis), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile testing. The results indicated that SPI/PVA films with the content of 40% complex plasticizers possessed better optical transmittance. All of the films exhibited only one T_g in DSC curves. Moreover, the SPI/PVA films with complex plasticizers had higher thermal stability and mechanical properties, as a result of the strong interaction between complex plasticizers and SPI/PVA. The SPI/PVA materials will be promising for the application in the field of package and container, substituting for the nongreen polymers.

Abstract: Polylactic acid (PLA), the biodegradable materials, mainly using biobase as raw materials, is the biodegradable polyester manufactured with fermentation and chemical synthesis, or polymerization of monomers from petrochemical products. The polymer usually made with the renewable resources, such as microorganism, plants and animals, will be decomposed into water and carbon dioxide if the natural landfill or compost environment has sufficient moisture, temperature, oxygen and suitable microorganism. Therefore, this paper aims to improve the hydrolysis rate of the PLA during the whole decomposition process and to increase the decomposition rate of PLA in the natural environment. In this paper, Taguchi method was used for the parameter design of PLA hydrolysis and focusing on choosing the conditions that would affect PLA hydrolysis as control factors, for example, temperature, bacteria, ventilation degree and nutrient. Meanwhile, the experiment was conducted with L8 orthogonal array and analysis of variance to find out the significant factor and the optimal conditions of PLA hydrolysis. We found the temperature and bacteria are signify factors by the variance. Lastly, confirmation experiments verified the reproducibility of this experiment. Confirmed by the experiments, results showed that the obtained SN ratios were greater than the rate of eight PLA hydrolysis experiments and this means the experiment is reliable.

Abstract: Among medicinal plants, flower and fruit plants take up a large proportion. This paper analyses ecological environment conditions such as temperature, light, water and soil nutrients having influence on growth of these kinds of medicinal plants. Furthermore, it discusses the relationships among three dormancy regulation and control factors i.e. bud and branch, underground and overground, and reproductive growth and vegetative growth. Lastly, it summarizes technical points of cultivation and management of these kinds of medicinal plants and key control measures, which provide significant theoretical basis for the improvement of yield and quality of these kinds of medicinal plants and the change from wild species to cultivated species.

Abstract: Antioxidants are the chemical substances that reduce or prevent oxidation. The present study aimed to assess in vitro antioxidant activities of ethanol extracts Hyptis rhomboidea. DPPH, ABTS and FRAP assays were used for characterization of antioxidant activities of several extracts. Eventually, the promising extract was the ethyl acetate (EAc) extract, The analyzed extracts exhibited that antioxidant activities varied considerably as function of extracts. The highest DPPH• scavenging ability was found in Y_6-8，which was divided from EAc by silica column, the lowest IC₅₀ value (6.9μg/ml), followed by Y_6-9 (11.7μg/ml) and the TEAC of Y_6-8 and Y_6-9were greater than positive control trolox. The same tendency was observed using ABTS and FRAP assays. These results suggest that the H. rhomboidea shows a better antioxidant activity, especially in the EAc extract and these results would be a guide in the selection of potential cultivars which are used in food and chemical industry and fresh market.

Abstract: Silver-deposited zinc oxide whisker (Ag/ZnOw) composites with different Ag/Zn molar ratios (MRs) were successfully synthesized by a simple method. Subsequently, the structure and properties of these composites were characterized using various tests. It is found that the silver nanoparticles are located on the root of ZnOw, which is beneficial for the antibacterial and photocatalytic performance of ZnOw. The Ag/ZnOw composite exhibits better antibacterial and photocatalytic activities than that of the pure ZnOw, and the efficiency of both properties increase with increasing molar ratio of Ag/Zn. Moreover, the mechanism which governs the photocatalytic property of the composite has also been discussed thoroughly.