Abstract
The core idea of Pragma-dialectical Theory is critical discussion which means resolving disagreement via argumentative dialogues. The Pragmatic-dialectic Model describing critical discussion ...has not only reasonableness and validness in logic, but also rhetorical effectiveness and pragmatic properties in intra-cultural context. However, the model cannot appropriately describe intercultural discussion since the discussants try to negotiate both in meaning and in divergence. People from different cultures do not necessarily behave pragmatically in the same way. In order to better describe the process of intercultural discussion, an exploratory approach was taken to first propose modifications of the model and then to confirm the modified model in a case study. The modifications include two aspects: first, its rhetorical and pragmatic properties can be expanded by taking Burke’s “Identification” and by replacing “speech acts” with more comprehensive “pragmatic acts”; second, the
argumentation stage
can be explored further with “motivation” and “mediation” added to the model. The case study reveals that the discussants with the motivation to seek common substances could take proper pragmatic acts to negotiate on certain substances, and that the mediation by the third party and by the discussants exerted influence both on the motivation and on the pragmatic acts. The modified model is expected to broaden the application scope of Pragma-dialectical theory to intercultural communication, and to better explain many kinds of intercultural discussions.
The increasing consumption of fresh-like food products requires the development of mild processing technologies without loss of nutritional value and sensory quality of foods. Non-thermal plasma ...(NTP) is an emerging and promising technology for extending the shelf-life of food products. However, the further development of a novel preservation technology should base on the adequate understandings of the effects on microbial behaviors. Therefore, the aim of this review is to provide an overview of the inactivation mechanisms of NTP technology on microbes. Topics covered are the basic introduction of NTP, the intrinsic and extrinsic factors affecting microbial inactivation effect and the probable mechanisms for microbial inactivation. Many factors, including processing parameters, environmental conditions and microbial properties have been shown to influence the bactericidal effect of NTP. According to previous research, the inhibitory activity of NTP against microbes includes biological and physical scenarios, though the exact mechanisms still remain unknown, requiring more investigations in the future.
•The intrinsic and extrinsic factors affecting bactericidal efficacy of non-thermal plasma were reviewed.•The probable inactivation mechanisms in biological and physical aspects by non-thermal plasma were summarized.•The non-thermal plasma induced microbial physiological alterations were shown.•The safe application of non-thermal plasma in the future for food industry was proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Ultrasonication was applied to the thawing process of bighead carp.•Differences of thawing methods on quality of slow/fast frozen bighead carp were compared.•Shorten thawing time by ultrasound was ...observed.•Fast frozen samples lost massive water after water immersion or ultrasonic thawing.•Freezing-thawing cycles did not affect the primary protein structure of fish samples.
Effects of ultrasound-assisted thawing (UAT), air thawing (AT) and water immersion thawing (WIT) on the quality of slow freezing (SF)/fast freezing (FF) bighead carp (Aristichthys nobilis) fillets were investigated. The thawing time of AT, WIT and UAT were 138, 30 and 12 min, respectively, indicating that UAT improved the thawing efficiency. UAT maintained the color and pH, and inhibited the lipid oxidation of SF/FF samples. For SF samples, thawing methods did not affect water retention and muscle structure. However, massive water loss and muscle destruction were observed in FF-WIT and FF-UAT samples. The AT did not produce any structural muscle damage; instead, it maintained the water retention in FF samples and prevented the FF fish fillets from massive water loss. No significant difference in the primary protein structure was observed among all samples. UAT can be an alternative strategy to the traditional thawing of SF fish fillets.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The influence of trophic status on the distribution of hydrophobic organic contaminants (HOCs) in different subtropical shallow waters at large spatial scales remains largely unknown. In this study, ...samples of surface sediments, water, total suspended particles, phytoplankton, and zooplankton were simultaneously collected from 83 sampling sites in 20 subtropical oligotrophic to hyper-eutrophic shallow lakes in China to investigate the influence of trophic status on the spatial distribution and sinking fluxes of 16 polycyclic aromatic hydrocarbons (PAHs). The total concentration of the 16 PAHs (ΣPAH16) in the water columns of these lakes varied from 0.22 to 5.81 μg L−1, and increased with the trophic state index (TSI) and phytoplankton biomass. Phytoplankton were the dominant reservoir for the PAHs in the water column. However, the fraction of ΣPAH16 in phytoplankton decreased with the TSI. The average sinking flux of ΣPAH16 of the individual lakes varied from 2257.1 to 261674.1 mg m−2 d−1, and increased with the TSI of the lakes. The concentration of ΣPAH16 in the surface sediments ranged from 385.77 to 3784.37 ng gdw−1, and increased with the TSI and the ratio of phycocyanin/sediment organic carbon. It suggested that cyanobacterial biomass affected by trophic status dominated the occurrence of the PAHs in the surface sediments of these lakes. Biomass dilution and the biological pump affected the accumulation of the PAHs in phytoplankton, and zooplankton, and had more influence on the PAHs with higher hydrophobicity. Both the bioconcentration factors and bioaccumulation factors of the PAHs decreased with the TSI. No biomagnification was observed for the PAHs from phytoplankton to zooplankton in these lakes in spring. Our study provided novel knowledge for the coupling between eutrophication and HOCs in 20 subtropical shallow lakes with different trophic status.
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•ΣPAH16 in the water column significantly increased with lake trophic state index.•Phytoplankton were the dominant reservoir for the PAHs in the lake water column.•Cyanobacterial biomass affected the occurrence of the PAHs in surface sediments.•Biomass dilution and biological pump dominated the accumulation of PAHs by plankton.•BCF and BAF of the PAHs accumulated by plankton decreased with trophic state index.
Trophic status affected the occurrence of 16 PAHs in the water columns and surface sediments, and their bioaccumulation in plankton food webs of twenty Chinese lakes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Microfluidization and ultrasonication were utilized to modify pectin.•Modified pectin showed lower particle size, molecular weight and polydispersity.•Modified pectin owned higher DPPH radical ...scavenging capacity and lower viscosity.•Modified pectin showed higher emulsion stability and interfacial loading.•Modified pectin improved encapsulation functionality to protect vitamin D3.
In this study, modified citrus pectin treated with a combination of microfluidization and ultrasonication was compared to the original and ultrasonication treated pectin on hydrodynamic diameter, molecular weight, polydispersity, zeta potential, apparent viscosity, Fourier-transform infrared spectroscopy (FTIR), 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging capacity, scanning electron microscope (SEM), atomic force microscopy (AFM), their emulsifying properties and encapsulation properties. Modified pectin treated with a combination of microfluidization and moderate ultrasonication (MUB) was found to have lowest hydrodynamic diameter (418 nm), molecular weight (237.69 kDa) and polydispersity (0.12), and relatively low apparent viscosity among all pectin samples. Furthermore, it showed significantly higher DPPH radical scavenging capacity than the original pectin although only slightly higher than that of ultrasonication treated one (UB). MUB showed a thin fibrous morphology and decreased degree of branching from SEM and AFM. Emulsion stabilized by MUB had highest centrifugal and thermal stability compared to emulsions stabilized by UB and the original pectin. This could be attributed to higher interfacial loading of MUB (17.90 mg/m2) forming more compact interfacial layer observed by confocal laser scanning microscopy (CLSM). Moreover, both MUB and UB exhibited improved encapsulation functionality to protect cholecalciferol (vitamin D3) from UV degradation compared to the original pectin.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Domestic cooking methods on phytochemicals and antioxidant activity were systemic evaluated.•Stir-frying and air frying on phytochemicals and antioxidant were first studied.•Antioxidant activity was ...well accordance with total phenolic while showed least accordance with vitamin C.
The effects of domestic cooking methods (boiling, baking, steaming, microwaving, frying, and stir-frying) and a new cooking method (air-frying) on the composition of phytochemicals (phenolics, anthocyanins, and carotenoids) and the antioxidant activity in purple-fleshed potatoes were investigated. Compared with raw potatoes, reductions of 23.59–90.42%, 7.09–72.44%, 7.45–83.15%, and 20.15–76.16% in the vitamin C, total phenolic, anthocyanin and carotenoid contents, respectively, was observed after cooking. Decreases of 7.88%, 21.55%, 22.48, 6.31%, and 61.38% in DPPH radical-scavenging activity was also observed after boiling, steaming, baking, microwaving and stir-frying, respectively, whereas an increase of 30.52% was noted after air-frying. A correlation analysis revealed that the antioxidant activity was in accordance with the total phenolic content and that this activity showed the lowest correlation with the vitamin C content. Among all of the cooking methods investigated in this study, stir-frying retained only slight levels of the phytochemicals and antioxidant activity observed in raw potatoes, whereas steaming and microwaving were able to retain most of the health-promoting compounds found in raw potatoes and may thus be suitable methods for cooking potatoes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
As a nonthermal sterilization technique, ultrasound has attracted great interest in the field of food preservation. In this study, flow cytometry and transmission electron microscopy were employed to ...investigate ultrasound-induced damage to Escherichia coli and Staphylococcus aureus. For flow cytometry studies, single staining with propidium iodide (PI) or carboxyfluorescein diacetate (cFDA) revealed that ultrasound treatment caused cell death by compromising membrane integrity, inactivating intracellular esterases, and inhibiting metabolic performance. The results showed that ultrasound damage was independent of initial bacterial concentrations, while the mechanism of cellular damage differed according to the bacterial species. For the Gram-negative bacterium E. coli, ultrasound worked first on the outer membrane rather than the cytoplasmic membrane. Based on the double-staining results, we inferred that ultrasound treatment might be an all-or-nothing process: cells ruptured and disintegrated by ultrasound cannot be revived, which can be considered an advantage of ultrasound over other nonthermal techniques. Transmission electron microscopy studies revealed that the mechanism of ultrasound-induced damage was multitarget inactivation, involving the cell wall, cytoplasmic membrane, and inner structure. Understanding of the irreversible antibacterial action of ultrasound has great significance for its further utilization in the food industry.
•Ultrasound induced fissures and pores on rice granule surface.•Amorphous region of starch was destroyed by ultrasound rather than crystalline region.•Ultrasound treatments improved the uniformity of ...starch particle size.•Ultrasound-treated starch showed a similar pasting profiles to the native starch.
To further investigate how controlled ultrasound treatments affect the morphology, physical property and fine structure of rice starch granules, the starch suspended in water was treated with different ultrasonic power levels (150, 300, 450 and 600 W) at 25 °C for 20 min. XRD, FT-IR and Raman spectroscopy were performed to characterise the long-range and short-range ordered structure of starch granules. Results indicated that ultrasound slightly destroyed the amorphous region of starch granules, while the A-type crystalline pattern remained unchanged. The result of chain length distributions showed that the fine structure of rice starch was not significantly changed by ultrasound treatment. SEM and particle size distribution demonstrated that ultrasound induced fissures and pores on the granule surface and elevated the homogeneity of granules, with minimum effect on the granule size. In addition, the thermal and pasting properties of rice starch were also measured by DSC and RVA. Results showed that after ultrasound treatments, the peak and breakdown viscosity increased, while the peak time, pasting temperature and gelatinisation enthalpy decreased. Overall, controlled ultrasound treatments dominantly modified the morphology and physical property of rice starch rather than the fine structure, providing additional information for the application of ultrasound on starch modification.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
► The effects of ultrasound on the molecular weight, structure and rheological properties of apple pectin were investigated. ► The degradation products had a uniform and narrow distribution of ...molecular weight. ► Degradation kinetics model of apple pectin fitted to 1/Mt−1/M0=kt from 5 to 45°C. ► Ultrasound treatment could not alter the primary structure properties of apple pectin. ► The viscosity of apple pectin decreased after ultrasound treatment.
The effects of ultrasound on the molecular weight of apple pectin were investigated. The structure and rheological properties of the degradation products were also tentatively identified by High Performance Liquid Chromatography–Photodiode Array Detector (HPLC–PAD), Infrared spectroscopy (IR), Nuclear Magnetic Resonance spectroscopy (NMR) and Rheometer. The results indicated that the weight-average molecular weight of apple pectin decreased obviously after ultrasound treatment. The molecular weight of degradation products had a uniform and narrow distribution. Ultrasound intensity and temperature play an important role in the degradation reaction. Degradation kinetics model of apple pectin fitted to 1/Mt−1/M0=kt from 5 to 45°C. The degree of methylation of apple pectin reduced according to IR analysis when ultrasound was applied. Ultrasound treatment could not alter the primary structure of apple pectin according to the results determined by HPLC, IR and NMR. Meanwhile, the viscosity of apple pectin was 103 times as large as that of ultrasound-treated apple pectin. The ultrasound-treated apple pectin showed predominantly viscous responses (G′<G″) over the same frequency range. The results suggested that ultrasound provided a viable alternative method for the modification of pectin.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
To argue tactfully is a goal in argumentative writing, which entails balanced argumentation schema. Although computer-supported collaborative learning (CSCL) has been widely acknowledged as language ...learning mediation, especially in writing, few studies investigate its effectiveness in activating the balanced argumentation schema. This study explores the effectiveness of QQ group discussion, a kind of CSCL mediation most popular in China, in argumentative writing by means of quasi-experiment and interview. Fifty-six second-year college students in an English Department participated in this study. The experimental group were asked to have a pre-writing QQ group discussion on a disputable topic while the control group had an in-class face-to-face discussion (a regular teaching method for English majors). Content analysis of the essays was made to investigate the use of Counterargument elements, Qualifier and Concession. The results show that the two groups had no difference in the use of Counterargument-claim and Rebuttal. However, the experimental group surpassed the control group in Counterargument-data, Concession and Qualifier, which signifies more argumentativeness and tactfulness. In the delayed post-test this group still performed better. The interview transcriptions were coded and analyzed by inductive content analysis with the functions of QQ discussion as the themes. The result not only supported that of the experiment, but also revealed why and how QQ mediation could help activate the balanced argumentation schema. It is suggested that CSCL mediation should be promoted in argumentative writing instruction so that the students could write argumentatively and tactfully.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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