Pacific Science Review A: Natural Science and Engineering最新文献

The purpose of this review article is to present to the readers a comprehensive progress report on the research performed on phenolics. Publications registered on the Scopus database from 2005 to 2015 were identified using various filters and keywords, and a critical analysis of the results was completed based on the publication trends. This review discusses and elucidates the intervention of phenolics in different disease areas with an emphasis on lifestyle diseases, occurrence of phenolics in different plant parts, methods used in extraction of phenolics, chromatographic techniques used in the detection of phenolics, and the standings of the top three countries based on research related to phenolics.

Traditionally, in Oman, the whole plant is used to treat the body, including treatment of anaemia, arthritis and skin inflammation. Crude extracts were prepared from the leaves of Dodonea viscosa (D. viscosa) using different polarities of solvents to isolate flavonoid compounds from the highest activity crude extract of the selected plant species collected from AL-Jabal AL Akhdar, Nizwa. The plant samples were collected, processed and extracted with methanol using a hot extraction method. The prepared crude extract was dissolved in water and successively fractioned with different polarities of solvents to produce hexane, chloroform, ethyl acetate, butanol and water crude extracts. The chloroform crude extract was used for the isolation of flavonoid compounds by thin layer chromatography, column chromatography and preparative thin layer chromatography. The free radical scavenging activity of the isolated pure compound and the different polarities of crude extracts were determined using the 1,1-diphenyl-2-picrylhydrazyl method.

The highest antioxidant activity in crude extracts from the leaves of D. viscosa was in the hexane and chloroform crude extracts, and the lowest activity was in the water crude extract, followed by hexane > chloroform > ethyl acetate > methanol > butanol > water crude extracts. One new prenylated flavonoid along with one known compound were isolated from the chloroform crude extract of D. viscosa and were identified by their chemical structures using mass spectrometry, one and two dimension nuclear magnetic resonance. The isolated pure compound also showed significant antioxidant activity against DPPH. This is the first report of antioxidant compounds in the leaves of D. viscosa. The results obtained from this study might be a good natural antioxidant from the selected plant crude extracts.

The objective of this paper is to develop a new solution methodology for matrix games, in which goals are viewed as intuitionistic fuzzy sets (IFSs) and the elements of the pay-off matrix are represented by triangular intuitionistic fuzzy numbers (TIFNs). In this methodology, a suitable ranking function is defined to establish an order relation between two TIFNs, and the concept of intuitionistic fuzzy (I-fuzzy) inequalities is interpreted. Utilizing these inequality relations and ranking functions, a pair of linear programming models is derived from a pair of auxiliary intuitionistic fuzzy programming models. Based on the aspiration levels, this pair of linear programming models is solved to determine the optimal strategies for both players of the game. The proposed method in this paper is illustrated with a voting share problem to demonstrate the validity and applicability of the method.

The Lightweight Steel Framing (LSF) system has been proposed as an economical and earthquake resistant system. Due to the lightweight nature of LSF structures, the seismic performance of middle-rise buildings has been improved. Currently, various numerical-analytical methods have been proposed for seismic assessment of conventional structures. Providing a perfect seismic Health Safety Environment (HSE) index has always been regarded as one of the analytical passive points. In this research, an LSF building was selected as a case study for Finite Element (FE) modelling, in which non-linear time-history analyses were undertaken. Material properties were defined according to the performed experimental studies. A novel approach was presented for the seismic HSE index of LSF systems using the simultaneous incorporation of the non-linear analysis results and the correction coefficient describing the seismic geotechnical effects. The presented seismic HSE index accurately demonstrates the seismic performance of the LSF structures. Additionally, a two-layer perceptron Artificial Neural Network (ANN) was trained using the results of the FE model, and a non-linear relationship was obtained to predict the seismic damage index. Finally, the proposed seismic HSE index was validated using statistical analyses, indicating that the proposed method does not yield a significant difference compared to the ANN results.

In this study, the validity and feasibility of UPT chaos for image encryption is demonstrated. This paper describes the design and implementation of a UPT chaotic signal generator for image encryption based on FPGA and Chua's system. In order to demonstrate the validity of the design, the signal generated by the chaotic signal generator is compared with Matlab simulations and used in an image encryption experiment. All of the experimental results indicate that using a UPT chaotic signal generator for image encryption is both practical and effective.

Plants are a good source for discovering new drugs for human benefit. The objective of this study was to determine the total phenolic and flavonoid contents and to probe the antimicrobial and cytotoxic activities of fruit extracts of Ficus sycomorus (F. sycomorus), which is native to the Sultanate of Oman. A study was conducted to measure the total phenolic and flavonoid contents of the methanol extract of this fruit and its derived fractions [n-hexane, chloroform, ethyl acetate, butanol and residual aqueous fractions] by in vitro chemical analyses using the Folin-Ciocalteu reagent assay (FCR) and the aluminium chloride (AlCl₃) method. The antimicrobial and cytotoxic activities were assessed using the slightly modified agar disc diffusion method and the brine shrimp lethality (BSL) method. The results of the analysis of the total phenolic content in different fruits extracts showed a significant amount of phenolic compounds, ranging from 1.48 to 213.79 mg of GAE/100 g of powder weight. However, the range of the total flavonoid content among the fruit extracts was found to be 0.100–0.527 mg QE/100 g of powder weight. The antimicrobial activity of the crude fruit extracts at different concentrations against four Gram-positive and Gram-negative bacterial strains, Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Haemophilus influenza (H. influenza), and Proteus spp (P. spp), showed strong activity in the range of 0–15 mm. The highest cytotoxic activity among the same extracts was that of the methanol extract, which had a LC₅₀ value of 1.48 μg/mL, followed by hexane, chloroform, butanol, water and ethyl acetate, with LC₅₀ values of 2.13, 3.16, 7.49, 133.04, and 213.79 μg/mL, respectively, in comparison to the control, DMSO. The findings of the present study suggest that the fruit extracts have significant amounts of total phenolic and flavonoid compounds with potential cytotoxic and antimicrobial activities.

In this paper, we define three operations on intuitionistic fuzzy graphs, viz. direct product, semi-strong product and strong product. In addition, we investigated many interesting results regarding the operations. Moreover, it is demonstrated that any of the products of strong intuitionistic fuzzy graphs are strong intuitionistic fuzzy graphs. Finally, we defined product intuitionistic fuzzy graphs and investigated many interesting results.

This paper introduces two newly developed near-maximum likelihood detectors, named pseudohexadecimal and modified pseudohexadecimal near-maximum likelihood detectors. These two detectors are tested against a pseudoquaternary near-maximum likelihood detector using data transmission at 9.6 kb/s over a telephone channel. Simulation results demonstrate that the performance of the pseudohexadecimal detector is better than the performance of the modified pseudohexadecimal detector, and the latter is better than the pseudoquaternary detector.

This paper presents a new modified algorithm of 16 kb/s ADPCM. The modification is related to the adaptive predictor rather than the adaptive quantiser. The purpose of this modification is to reduce the nonlinear distortion introduced by ADPCM when a high data rate signal passes through it. The performances of standard and modified algorithms are studied using a QAM signal at a data rate of 9.6 kb/s. The simulation results show that the performance of modified ADPCM is better than the standard ADPCM.

Service-oriented architecture assures the flexibility of enterprise application development to support agile reactions when businesses change. However, the method of developing a service by combining business and constraints consumes much effort because the entire combination of logic may be changed according to the business rule changes. To improve the current method, this paper applies the aspect-oriented approach to service system development. The rule concern is proposed, and the core and cross cutting concerns of the aspect-oriented approach are included. The rule concern is extracted from business rules included in business processes and services. The rule concern is classified into process rule aspects and service rule aspects according to the level of the rule. In the proposed approach, the system is modularized into core, cross cutting and rule concerns by the separation of concerns, and they are maintained independently. Therefore, the adaptability, reusability, and maintainability of the service system will be enhanced.