教学课程资源库 更多>>

关键词： iCVD   Janus membrane   membrane distillation   physicochemical inhibition   wettability  

摘要： Membranes with asymmetric wettability-Janus membranes-have recently received considerable attention for a variety of critical applications. Here, we report on a simple approach to introduce asymmetric wettability into hydrophilic porous domains. Our approach is based on the physicochemical-selective deposition of polytetrafluoroethylene (PTFE) on hydrophilic polymeric substrates. To achieve selective deposition of PTFE, we inhibit the polymerization reaction within the porous domain. We prefill the substrates with glycerol, containing a known amount of free radical inhibitor, and utilize initiated chemical vapor deposition (iCVD) for the polymerization of PTFE. We show that the glycerol/inhibitor mixture hinders the deposition of PTFE within the membrane pores. As a result, the surface of the substrates remains open and porous. The fabricated Janus membranes show stable wetting-resistant properties, evaluated through sessile drop contact angle measurements and direct contact membrane distillation (DCMD).

关键词： Wheat starch   Fine structure   Physicochemical properties   Size exclusion chromatography   Noodles  

摘要： The relationship between wheat-starch molecular structures (obtained by size-exclusion chromatography), physicochemical properties (swelling power (SP), pasting and thermal properties) and noodle eating qualities were examined. SP was negatively correlated with amylose content and positively correlated with the amounts of amylose long chains and short amylopectin chains. Peak viscosity (PV) was negatively correlated with amylose content and the amount of long amylopectin chains, but positively correlated with the lengths of long amylopectin chains and the amount of short amylopectin chains. Noodles adhesiveness was negatively correlated with the amount of short amylose chains, short amylopectin chains, PV and final viscosity (FV). Noodles hardness was positively correlated with amylose content and long amylopectin chains, but negatively correlated with short amylopectin chains, SP, PV, and FV. All these observations are explained in terms of molecular mechanisms. This provides the first associations between starch molecular fine structures (instead of only amylose content) responsible for starch properties of importance in making noodles.

关键词： Carica papaya leaves extract   Virgin coconut oil   Whey protein   Edible emulsion   Sensory acceptability   Alternative natural remedies  

摘要： Carica papaya Linnaeus commonly known as papaya is widely grown in Malaysia as a herbaceous plant with phytochemicals for a variety of use, particularly in the medical field. The therapeutic medicinal way of treating dengue fever using papaya leave extract mainly involves consumption a raw concoction and is very distasteful. Therefore, a study was carried out to develop stable emulsion with an acceptable taste through a ternary phase diagram system (TPDS), which comprised virgin coconut oil (VCO), isolated whey protein (WPI) and Carica papaya leaves extract (CPLE). The TPDS was developed using Chemix Software version 3.6 to identify the existence of homogenous phase region. In the first phase, a total of 11 selected samples (named as A to K) with concentrations ranging from 20% to 30% (w/w) of WPI from the homogenous phase region were used to select the best emulsion selection. Sample I with a composition of 25, 30 and 45% (w/w) comprising VCO, WPI and CPLE was selected and considered as the best and stable emulsion. In the second phase, sample I (renamed as sample M) underwent an addition of + 2% (sample L) and reduction of -2% (sample N) VCO. Analysis was carried out such as emulsion stability test (creaming index), pH value, viscosity, color and storage stability (4, 28 and 45 degrees C). The control sample was CPLE without any VCO or WPI. Sensory evaluation was also conducted to handpick the best formulation favored by 30 panellists. The sensory evaluation was conducted on samples L, M, N and CPLE using 7-point hedonic scale for preference on color, viscosity, odor, bitterness and overall acceptance attributes. The results showed that centrifugation test exhibited a stable emulsion for all the three samples (p > 0.05) L, M and N. In fact, there were differences between all the samples (p < 0.05) for pH, viscosity, and coloration of L* and b* values. For the storage stability test, all formulations were stable at 4 degrees C and there were no creaming layer and c

关键词： Nanofibrous composite scaffold   Electrospinning   Magnetic properties   Cobalt-zinc ferrite  

摘要： In the current research, a novel poly(epsilon-caprolactone) nanofibrous composite scaffold including CZF-NPs1 (cobalt-zinc ferrite nanoparticles) was investigated to study the physical, mechanical and biological properties of new magnetic nanofibrous materials and then to evaluate the effect of applied electromagnetic field on biological properties of these scaffolds. It was observed that the incorporation of CZF-NPs up to 3 wt.% leads to decrease in nanofibers' diameter to 466 nm. By raising the content of CZF-NPs, hydrophilicity and biodegradation of magnetic nanofibrous scaffolds improved significantly. In addition, the mechanical properties of nanofibers such as stress at break point was interestingly increased in the sample with 3 wt.% of CZF-NPs. The results of biocompatibility, cell adhesion and cell staining assays with L929 cells are much more improved in nanofibers embedded with CZF-NPs in the presence of external electromagnetic field (EMF). According to this study, magnetic nanofibrous scaffolds composed of PCL/CZF-NPs could be considered as a promising candidate to regenerate damaged tissues.

关键词： Hydrolysis of Schiff bases   4-(phenylethynyl)benzaldehyde as AIEgens   Cytotoxicity of IRAs  

摘要： A series of new Schiff bases containing the phenyl-ethynyl-phenyl system was synthesized and their thermal stability, photophysical and electrochemical properties were investigated. Moreover, DFT calculations were performed to obtain the optimized ground-state geometry and distribution of the HOMO and LUMO levels as well as IR spectra of the prepared compounds. It was found that, the photoluminescence of synthesized imines was negligible in all investigated organic solvents except for the PBS/ACN mixture. As was proved in further studies, this phenomenon was related to the partial hydrolysis of imines, which is the source of the fluorogenic aldehyde causing the aggreggacion incrased-emision effect. In further research, due to the susceptibility of the azomethines to partial hydrolysis, the biological activity of 2-{(E)-[4-(phenylethynyl) phenyl]imino}phenol (1b), substrate (2-aminophenol) and Cu(II)-1b complex was analyzed. The biological tests showed, that 1b (as example of imine resveratrol analogue), demonstrated its increased cytostatic activity in prostate cancer cellular system. It was proved that the non-hydrolyzed imine was crucial for the cytotoxic effect. This activity could be ascribed to its Cu(II) complexing capability as showed in our previous research.

关键词： dragon bamboo   planting pattern   slope type   soil physicochemical properties   soil microbial community  

摘要： Dragon bamboo (Dendrocalamus giganteus) is a giant sympodial bamboo species widely distributed in Asia. However, it remains unclear how dragon bamboo and soil microbes interact to affect soil properties. In this study, we investigated the planting patterns (semi-natural and artificial) on different slopes (sunny and shady) to determine the effects on soil properties and microbial community. The results showed that the soil in which dragon bamboo was grown was acidic, with a pH value of similar to 5. Also, the soil organic matter content, nitrogen hydrolysate concentration, total nitrogen, available potassium, and total potassium of the dragon bamboo semi-natural forest significantly improved, especially on the sunny slope. In contrast, the available phosphorus level was higher in the artificial bamboo forest, probably owing to the phosphate fertilizer application. The bacterial and fungal diversity and the bacterial abundance were all higher on the sunny slope of the semi-natural forest than those in the other samples. The microbial operational taxonomic units (OTUs) shared between the shady and sunny slopes accounted for 47.8-62.2%, but the core OTUs of all samples were only 24.4-30.4% of each sample, suggesting that the slope type had a significant effect on the microbial community. Some acido-philic microbes, such as Acidobacteria groups,StreptomycesandMortierella, became dominant in dragon bamboo forest soil. A PICRUSt analysis of the bacterial functional groups revealed that post-translational modification, cell division, and coenzyme transport and metabolism were abundant in the semi-natural forest. However, some microorganisms with strong stress resistance might be activated in the artificial forest. Taken together, these results illustrated the influence of dragon bamboo growth on soil physicochemical property and microbial community, which might help understand the growth status of dragon bamboo under different planting patterns.

关键词： Pulsed electric fields   Carrot   Vacuum drying   Rehydration   Color  

摘要： The effect of pulsed electric fields (PEF) on the kinetics of vacuum drying (VD) and rehydration of carrot tissue was studied. The intensity of PEF treatment was E = 0.6 kV/cm and the total PEF treatment duration was tpEF = 0.1 s. The VD was performed at sub-atmospheric pressure p = 3.03 x 10(4) Pa for different temperatures T-d = 25 degrees C and 90 degrees C. During VD, the kinetics of moisture removal and temperature evolution inside of untreated and PEF pretreated samples were studied. The color and structure of the samples were also investigated. PEF pretreatment enhanced VD kinetics at different studied temperatures. However, its effect on VD was more evident at lower drying temperatures. With the PEF pretreatment, the drying time was reduced by 55% and 33% at 25 degrees C and 90 C respectively. After the drying and rehydration process, the change in color of PEF pretreated samples was less significant compared to untreated ones. After rehydration, the untreated and PEF pretreated samples were nearly restored to their initial form and size.

关键词： Cassava   Starch   Physicochemical properties   Fine structure   Correlations  

摘要： Apparent amylose content (AAC), resistant starch (RS) content, pasting, gelatinization, retrogradation properties, and fine structural parameters amongst starches from five Thai cassava cultivars grown in two different locations were determined. Results indicated that significant differences among different varieties were found for most traits. The AAC, gelatinization onset (T-o) and peak temperature (T-p), the ratio of peak heights of amylopectin (h(AP2)/h(AP1)) and chain length distribution (CLD) of amylopectin fa, fb2, fb3 and average CLD ((X) over bar) were mainly affected by genotypic effects. The peak viscosity (PV), breakdown (BD), molecular size of amylose (R-h,R- AM) and amylopectin (R-h,R- AP), average molecular size ((R) over bar (h)), the position of amylopectin peak (X-AP1) and fb1 were mainly affected by environmental effects. The effects of the genotype x environment interaction were significant for BD, R-h,( AM), R-h,R- AP, h(AP2)/R-Ap1 and fb2 values. RS was negatively correlated with the amount of amylopectin fa chains. PV and BD were affected by R-h,R- AM, R-h,R- AP, X-AP1, X-AP2, and the amount of fb1 chains. T-o and T-p were affected by X-Ap1, X-Ap2, fb1 and fb2. These results enhance our understanding of the structure-function relations of starches and are useful for the application of starch in the food industry and for breeding programs to improve the cassava starch quality.

关键词： Wine   Physico-chemical indices   Aroma compounds   Varietal discrimination   Modeling  

摘要： Wine comprises a beloved food and human companion since the early times of humans on earth. In this study, wine samples of different type (red, white, and rose) and variety (Agiorgitiko, Augoustiatis, Cabernet Sauvignon, Syrah, Vlahiko, Assyrtiko, Chardonnay, Debina, Moschofilero, Vidiano, Syrah plus Mandilari, and Xinomavro) were subjected to physico-chemical and aroma compounds analyses, in an effort to characterize their identity and discriminate these samples according to variety using statistics. Results showed significant differences (p < 0.05) for wine samples of different variety in regard to the measured physico-chemical parameters (pH, electrical conductivity, total dissolved solids, salinity, L*, a*, b*, and Chroma*) and aroma compounds (alcohols, esters, phenolic compounds, pyran compounds, and terpenoids/norisoprenoids). Application of multivariate analysis of variance, linear discriminant analysis, and weighted least-squares regression analysis fired up the perfect varietal discrimination (similar to 100%) of wine samples and modeling of results, contributing to new information in the literature about the identity of these wine varieties.

关键词： Physicochemical property   Methyl benzoate   Microstructure   Hydrogen bond interaction  

摘要： Densities, speeds of sound, and viscosities of binary mixtures of methyl benzoate (MB) with ethanol, 1-propanol, and 1-butanol were measured at temperature ranging fromT = 293.2 to 313.2 K and refractive indices were determined atT = 303.2 K. Excess molar volumes,V-E, isentropic compressibility deviations increment kappa(s)and viscosity deviations, Delta eta, were obtained and fitted with the Redlich-Kister equation with satisfactory results. Based on the measured and derived physicochemical properties, the influence of the alkyl chain length of the alcohol on the molecular interactions of the studied mixtures was explored. The results show that both hydrogen bond interaction between carbonyl group of MB and hydroxyl group of alcohol and the packing efficiency, such as accommodation of alcohol in the interstice of MB, play an important role in the microstructure of the mixtures, which leads to the disruption of alcohol with the addition of MB. Moreover, by comparingV(E), increment kappa(s)and Delta eta values of MB (1) + alcohol (2) systems atT = 303.2 K, it is found that the strength of hydrogen bond interaction and the packing efficiency significantly weakens with increasing alkyl chain length of alcohol in going from ethanol to 1-butanol, resulting in theV(E)values of the studied systems gradually changing from a negative deviation to an S shape, the increment kappa(s)and Delta eta values have negative deviations, and the increment n(D)values have positive deviations. The obtained results will provide thermodynamic guidance for the industrial purification of methyl benzoate.