教学课程资源库 更多>>

关键词： Residue incorporation   Saline-alkali soil improvement   Soil microorganisms   Residue decomposition  

摘要： Soil salinization is becoming increasingly serious, threatening the development of ecological agriculture that aims at high yield, high efficiency and closed-loop cycles. In this study, residues of Jerusalem artichoke were incorporated in three soils differing in salinity, and the physical and chemical properties of soil and soil microbial community were characterized over time. After residue incorporation, the soil pH fluctuated between 6.8 and 8, trending toward neutrality;the soil salinity decreased significantly. The total nitrogen content increased significantly, whereas the soil organic matter content increased initially and then decreased. Soil microbiome abundance and diversity increased, with a significant increase in the population of moderate halophiles and cellulose-decomposing bacteria in soil. Compared with the genera adapted to medium-to-high salt concentration, the abundance and diversity of the low-salt genera were higher. The degradation rate of residues increased with time, with cellulose degradation being strongest, followed by hemicellulose, and finally lignin. In summary, incorporation of Jerusalem artichoke residues can improve soil physical and chemical properties and the microbial community structure, which provides a theoretical basis for improving saline-alkali soils, rational utilization of crop residues and promoting sustainable development of modern agriculture.

关键词： Mannich base   Ciprofloxacin   Physicochemical properties   Antibacterial   Anticancer   Caspase 3  

摘要： The design, synthesis and identification of a novel series of Mannich bases of ciprofloxacin was reported. Naphthol derivatives 2a and 2b showed highly potent cytotoxic activity among the tested compounds. Compound 2a showed broad spectrum antiproliferative activity with GI(50) of 2.5-6.79 mu M with remarkable selectivity towards renal and prostate cancers with selectivity ratios ranging from 0.17 to 6.79. Independently, 2a showed outstanding activity against colon cancer HOP-92 cell lines with IC50 of 6.66 mu M while 2b showed highly potent activity against ovarian cancer cell lines with IC50 of 0.97 mu M. Results showed that 2b induced cell cycle arrest at G2/M phase and apoptosis;compound 2b showed over-expression of caspase-3 protein level (449.2 +/- 7.95) compared to doxorubicin (578.7 +/- 14.4 pg/mL). Meanwhile, compounds 2a and 2b experienced outstanding activity against both Gram-positive and Gram-negative microorganisms. Interestingly, compound 2j experienced high activity against Escherichia coli and Pseudomonas aeruginosa with MIC of 0.036 and 0.043, respectively. Compound 2d revealed 27 folds and 22 folds, respectively increasing of activity over ciprofloxacin against Staphylococcus aureus and MRSA(reference strain). Compound 2d showed high activity against Staphylococcus aureus, MRSA (reference strain) and MRSA (clinical strain) with MIC of 0.57, 0.52, 0.082 mu g/mL, respectively. Interestingly, the most active tested compounds were found to have promising physicochemical and drug likeness properties. The Mannich bases 2j, 2d and 2g showed promising antibacterial activities, while naphthols 2a and 2b showed promising antiproliferative and antibacterial activities that require further optimization.

关键词： Peach   Transportation   Vibration   Frequency   Physico-mechanical  

摘要： Loss in fresh fruit and vegetables during transportation occurs mainly due to their susceptibility to mechanical damage. The quality loss caused by this damage depends on the shock and vibration frequencies. In this study, the effect of different vibration frequencies (5 Hz, 10 Hz, and 15 Hz) on the physico-mechanical and physicochemical properties of peach was investigated. The parameters such as energy absorption, mechanical hysteresis, and deformation volume were increased whereas mean geometric diameter, surface area, volume, degree of elasticity, deformation energy, and modulus of elasticity were decreased. Regarding physicochemical properties, pH and total soluble solid parameters increased whereas lightness (L*) value of peach decreased. The highest level of damage and mold growth were observed on the peach treated with 15 Hz frequency followed by 10 Hz and 5 Hz, respectively. The effect of all the frequencies on the physico-mechanical and physico-chemical properties of peach was statistically different. The results indicated that the increase in the vibration frequency causes higher mechanical damage in peach.

关键词： Amberlyst   anion exchanger   direct dye   removal   resins   sorption   wastewaters  

摘要： Intensive development of many industries, including textile, paper or plastic, which consume large amounts of water and generate huge amounts of wastewater-containing toxic dyes, contribute to pollution of the aquatic environment. Among many known methods of wastewater treatment, adsorption techniques are considered the most effective. In the present study, the weakly basic anion exchangers such as Amberlyst A21, Amberlyst A23 and Amberlyst A24 of the polystyrene, phenol-formaldehyde and polyacrylic matrices were used for C.I. Direct Yellow 50 removal from aqueous solutions. The equilibrium adsorption data were well fitted to the Langmuir adsorption isotherm. Kinetic studies were described by the pseudo-second order model. The pseudo-second order rate constants were in the range of 0.0609-0.0128 g/mg center dot min for Amberlyst A24, 0.0038-0.0015 g/mg center dot min for Amberlyst A21 and 1.1945-0.0032 g/mg center dot min for Amberlyst A23, and decreased with the increasing initial concentration of dye from 100-500 mg/L, respectively. There were observed auxiliaries (Na2CO3, Na2SO4, anionic and non-ionic surfactants) impact on the dye uptake. The polyacrylic resin Amberlyst A24 can be promising sorbent for C.I. Direct Yellow 50 removal as it is able to uptake 666.5 mg/g of the dye compared to the phenol-formaldehyde Amberlyst A23 which has a 284.3 mg/g capacity.

关键词： Soy protein isolate   Acidified gel   Fat   Gelation behaviour   Tribology   Confocal laser scanning microscopy  

摘要： The effect of different types of fat (anhydrous milk fat, palm stearin, soybean oil) and concentrations (0.5, 1, and 2%) in soy protein isolate (SPI) gel on their gelation behaviour (acidification, cooling, annealing and heating step), tribological, microstructure and textural properties were investigated. SPI gels made from soy protein isolate added with different fat types showed different gelation behaviour compared to control (without fat) by modulating the acidification time. Among all the gels, incorporating anhydrous milk fat into soy protein produced stronger and firmer gels (0.66-0.73 N) followed by palm stearin (0.64-0.68 N) and soybean oil (0.60-0.62 N). The apparent viscosity for all samples showed a shear thinning behaviour. The lowest coefficient of friction were observed from SPI gels added with 2% of anhydrous milk fat which indicating better lubrication properties. The gel particle sizes of all the samples were also not significantly different, although from microscopic images the soy protein with soybean oil showed smaller fat globules and more compact protein network. These results demonstrated that the presence of fats as a filler affects the firmness and gelling properties of SPI gel. The highest G' (similar to 1.4 kPa) and the lowest friction coefficient (0.24) of SPI gel obtained from 2% of anhydrous milk fat addition suggested the potential of incorporating anhydrous milk fat to provide desirable texture and pleasant mouthfeel in SPI gel.

关键词： Lubricants   oxidation   wear   coefficient of friction   chaulmoogra   cyclic fatty acids  

摘要： Due to environmental concerns, natural oils are increasingly being used as an alternative to mineral oil-based products such as lubricants. However, the use of edible oil for industrial application adversely affects their availability for edible purposes. Chaulmoogra oil is a non-edible oil obtained from the seeds of chaulmoogra tree that grows in wastelands. The fatty acid constituents of vegetable oils determine their properties. Presence of long-chain cyclic fatty acids like chaulmoogric acid, hydnocarpic acid and gorlic acid distinguishes chaulmoogra oil from other oils. Research on how cyclic fatty acids influence the properties of vegetable oils and affect their efficacy as base oils for lubricants is scarce in the literature. This paper presents a preliminary evaluation of the physicochemical, viscometric, oxidative and tribological properties of chaulmoogra oil as a lubricant base stock. Gas chromatography-mass spectroscopy, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy methods were used for structure elucidation. The viscometric analysis was conducted by using Brookfield viscometer. The tribological performance was evaluated by a four-ball apparatus as per ASTM D4172-94. Thermal and oxidative stabilities were evaluated by thermogravimetric/differential thermal analysis in nitrogen and oxygen environments. Pour point was assessed by ASTM D97 method and differential scanning calorimetry. Chaulmoogra oil has a viscosity of 9.2 cSt at 100 celcius and a viscosity index of 166. Though the coefficient of friction was better than a commercial lubricant of similar viscosity range (SAE 20W40), the wear scar diameter was comparatively higher. Addition of antiwear additive zinc dialkyl dithiophosphate showed considerable improvement in the wear performance of chaulmoogra oil. Chaulmoogra oil showed a high pour point value around 15 celcius which needs to be improved by appropriate pour point depressants. Environmental advantage, co

关键词： Nanostructures   Colloidal dispersions   Volatile oils   Nutmeg   Lavander  

摘要： Essential oils are characterized as complex compound mixtures with important pharmacological properties, yet they are sensitive to high temperatures, light, and the presence of oxygen. Nanotechnology is therefore used to improve stability, securing both quality and efficacy. To evaluate the stability of Lavandula dentata Linnaueus and Myristica fragrans Houtt essential oils when associated with nanostructures, nanoemulsions containing 5% essential oil with hydrophilic and lipophilic surfactants were developed through emulsification under high agitation. Fabrication of the formulations did not qualitatively or quantitatively affect the majority of the essential oil compounds being identificates by gasose cromatografy as main constituents (-) beta-pinene (24-31 %), 1-terpinen-4-ol (14-15 %), L alpha-pinene (13 %) and sabinene (10-15 %), in M. fragrans;e 1.8 cineol (50-52 %), fenchone (17-16 %) and camphor (15-13 %) for L. dentata. The systems were characterized in terms of average droplet size, polydispersity index, pH, zeta potential, and each essential oil's chemical composition (upon preparation), and for 90 days under the following storage conditions: refrigeration temperature, room temperature, and a controlled climatic chamber. After preparation: the droplet size of M. fragrans esential oil-loaded nanoemulsion (NE-MO) was 87.06 rim, its polydispersity index (PDI) was 0.17, the zeta potential value was-14.8 mV, and the pH was 5.62;L. dentata esential oil-loaded nanoemulsion (NE-LO) droplet size was 64.99 rim, its polydispersity index (PDI) was 0.26, zeta potential value was -11.1 mV, and the pH was 4.95. Investigation of these physicochemical response (particle size and polydispersity index) suggests that NE-MO presented intended responses and good stability over 3 months' and 15 days storage at refrigeration and room temperature, respectively;being that the pH of formulation was maintained unaltered in the three conditions. Produced nanoemulsions with essential

关键词： Theobromacacao   Cocoafermentation   Ecologicalsuccession   Microbiome   Starterinoculum   Chocolate  

摘要： Cocoa beans used for chocolate production are fermented seeds of Theobroma cacao obtained by a natural fermentation process. The flavors and chemical compounds produced during the fermentation process make this step one of the most important in fine chocolate production. Herein, an integrative analysis of the variation of microbial community structure, using a shotgun metagenomics approach and associated physicochemical features, was performed during fermentation of fine cocoa beans. Samples of Forastero variety (FOR) and a mixture of two hybrids (PS1319 and CCN51) (MIX) from Bahia, Brazil, were analyzed at 7 different times. In the beginning (0 h), the structures of microbial communities were very different between FOR and MIX, reflecting the original plant-associated microbiomes. The highest change in microbial community structures occurred at the first 24 h of fermentation, with a marked increase in temperature and acetic acid concentration, and pH decrease. At 24-48 h both microbial community structures were quite homogenous regarding temperature, acetic acid, succinic acid, pH, soluble proteins and total phenols. During 72-96 h, the community structure resembles an acidic and warmer environment, prevailing few acetic acid bacteria. Taxonomic richness and abundance at 72-144 h exhibited significant correlation with temperature, reducing sugars, succinic, and acetic acids. Finally, we recommend that dominant microbial species of spontaneous fine cocoa fermentations should be considered as inoculum in accordance with the farm/region and GMP to maintain a differential organoleptic feature for production of fine chocolate. In our study, a starter inoculum composed of Acetobacter pausterianus and Hanseniaspora opuntiae strains is indicated.

关键词： camel milk   fermented   culture bacteria   probiotic bacteria   monk fruit sweetener  

摘要： Camel milk, similar to cow milk, contains all of the essential nutrients as well as potentially health-beneficial compounds with anticarcinogenic, antihypertensive, and antioxidant properties. Camel milk has been used for the treatment of allergies to cow milk, diabetes, and autism. Camel milk helps decrease cholesterol levels in blood and improves metabolism. One of the most desirable food tastes is sweetness. However, the excessive ingestion of sugar negatively affects human health. Monk fruit sweetener is a natural, 0-calorie sweetener with many health-beneficial functions. Monk fruit sweetener helps decrease symptoms of asthma and diabetes, prevents oxidation and cancer, protects the liver, regulates immune function, and lowers glucose levels. Monk fruit sweetener is 100 to 250 times sweeter than sucrose. The objective of this study was to examine the influence of different concentrations of monk fruit sweetener on the physicochemical properties and microbiological counts of drinking yogurt made from camel milk. Camel milk drinking yogurt was produced with 0, 0.42, 1.27, and 2.54 g/L of monk fruit sweetener and stored for 42 d. The physicochemical characteristics and microbiological counts of yogurts were measured at d 1, 7, 14, 21, 28, 35, and 42. For the physicochemical characteristics, pH, titratable acidity, viscosity, and color [lightness-darkness (L*), red-green axis (a*), yellow-blue axis (b*), chroma (C*), and hue angle (h*)] values were evaluated. The counts of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus, conforms, and yeast and mold were determined. Three replications were conducted. The sweetener addition significantly influenced pH, viscosity, and color (a*, b*, C*, and h*) values. Control samples had significantly higher pH values, lower viscosity, lower b* and C* values, and higher h* values than the samples with 1.27 and 2.54 g/L of monk fruit sweetener. Growth of S. thermophilus, L. bulgaricus, and probiotic cu

关键词： IBMWP   QBR   IHF   Water quality   Oued Martil   Morocco  

摘要： An assessment of the water quality of the Oued Martil River basin (in northern Morocco) which is under natural and anthropogenic pressures was carried out over an annual cycle (spring, summer, autumn 2017 and winter 2018) at 20 sampling stations within the watershed. This assessment was conducted using biotic indices including the IBMWP (Iberian Biological Monitoring Working Party index), the QBR (Index of Riparian Quality) and the IHF (Fluvial Habitat Index). Physicochemical and bacteriological quality was also assessed based on twelve parameters (temperature, pH, electrical conductivity, dissolved oxygen, biological oxygen demand, chemical oxygen demand, suspended matter, sulphate, nitrite, nitrate, faecal coliforms, and faecal streptococci) of the surface waters of Oued Martil River basin. The scores of the biotic indices as well as the measurements of the physico-chemical and microbiological parameters classified the waters of the upstream reaches of the Oued Martil River as good quality while those of the downstream reaches were classified as poor quality.