教学课程资源库 更多>>

关键词： Fish collagen   tilapia skin   hybrid catfish skin   ACE inhibitory peptides  

摘要： The objectives of this study were to characterize physicochemical properties of two collagens, tilapia skin (TS) and hybrid catfish skin (HS). Angiotensin-converting enzyme (ACE) inhibitory peptides from extracted TS and HS collagen using pepsin were also determined. HS collagen had a higher amount of imino acid than TS collagen, while TS contained higher amounts of tyrosine (Tyr) and lysine (Lys). Fourier-transform infrared spectra of both collagens showed predominant helix structure. The HS collagen hydrolysate prepared by pepsin was fractionated using sequential ultrafiltration membranes, and the fraction with molecular weight (MW) <5 kDa showed the highest ACE inhibitory activity (p< .05). After cation exchange and two steps size exclusion chromatography, peptides showed ACE inhibitory activity of 72.06%. This study revealed that ACE inhibitory peptides derived from HS collagen could be developed as a functional food with potential antihypertensive properties.

关键词： Blue catfish   chesapeake Bay   physicochemical properties   protein quality  

摘要： Physicochemical attributes of Chesapeake Bay's blue catfish and quality of muscle protein isolates (PIs) as influenced by storage condition and extraction methods were investigated. All fish were within the maximum consumable size limit. Those obtained during the autumn/winter and in Year 2 were larger with firmer fillets than their counterparts during the spring/summer and in Year 1. Protein was the predominant nutrient component. Protein extraction yield ranged from 35.3 +/- 1.4% to 47.0 +/- 5.1%, and beta-sheet was the predominant secondary structure for all fish PIs. Salt-extracted PIs were whiter and had higher water holding capacity at neutral and alkali environments. The results of this study support the use of Chesapeake Bay blue catfish and muscle protein for potential value-added application.

关键词： Cobalt   lead   oxygen uptake rate   polycyclic aromatic hydrocarbon   toxicity tests  

摘要： Underground storage tanks used for auto oil spill waste contain many hazardous materials, including polycyclic aromatic hydrocarbons (PAHs) trace elements. These compounds pose a significant threat to the environment and affect negatively human health. The aim of this study was to characterize the soil of a former auto scrap yards in which oil spill tank leakage occurred in Sweden. The soil samples were collected from an area of 5 m(2)around an oil the tank which was highly contaminated with petroleum hydrocarbons (PHC) and trace elements (cobalt and lead). Another soil samples were collected from a nearby area that was not contaminated by PHC and they were considered as controls. The characterization of these soil samples was performed using two approaches. Analysis of the relevant physico-chemical soil properties included texture, organic matter, contaminant concentration and pH, while biological analyses were performed using three independent ecotoxicological tests with plant (Lepidium sativum), earthworm (Eisenia fetida) and soil microorganisms. Toxicity tests showed that contaminants had strongly negative effects on earthworm's development andL. sativumshoots dry biomass in both PHC contaminated and control soils. These two parameters were the most sensitive in reflecting toxicity of study soils. Oxygen uptake rate (OUR) in aqueous phase was four times higher than that of the solid phase even though a similar trend was observed in both phases (aqueous and solid). Moreover, microorganism's respiration was high in PHC contaminated soils in comparison to control soils due to the mineralization of readily available OM and/or organic pollutants as well as the inhibitory effect of TE on soil respiration. The results clearly demonstrated that combination of chemical analyses with three toxicity tests was appropriate to characterize mixed PHC and TE contaminated soils.

关键词： Biocompatibility  

摘要： Biomedical scientists use chemistry-driven processes found in nature as an inspiration to design biomaterials as promising diagnostic tools, therapeutic solutions, or tissue substitutes. While substantial consideration is devoted to the design and validation of biomaterials, the nature of their interactions with the surrounding biological microenvironment is commonly neglected. This gap of knowledge could be owing to our poor understanding of biochemical signaling pathways, lack of reliable techniques for designing biomaterials with optimal physicochemical properties, and/or poor stability of biomaterial properties after implantation. The success of host responses to biomaterials, known as biocompatibility, depends on chemical principles as the root of both cell signaling pathways in the body and how the biomaterial surface is designed. Most of the current review papers have discussed chemical engineering and biological principles of designing biomaterials as separate topics, which has resulted in neglecting the main role of chemistry in this field. In this review, we discuss biocompatibility in the context of chemistry, what it is and how to assess it, while describing contributions from both biochemical cues and biomaterials as well as the means of harmonizing them. We address both biochemical signal-transduction pathways and engineering principles of designing a biomaterial with an emphasis on its surface physicochemistry. As we aim to show the role of chemistry in the crosstalk between the surface physicochemical properties and body responses, we concisely highlight the main biochemical signal-transduction pathways involved in the biocompatibility complex. Finally, we discuss the progress and challenges associated with the current strategies used for improving the chemical and physical interactions between cells and biomaterial surface.

关键词： Ethers  

摘要： Correction for 'The effects of the position of the ether oxygen atom in pyrrolidinium-based room temperature ionic liquids on their physicochemical properties' by Kazuki Yoshiiet al.,Phys. Chem. Chem. Phys., 2020, DOI:;10.1039/d0cp02662j.

关键词： animal models   bioavailability   lipid based formulations   lymphatic absorption   lymph duct cannulation  

摘要： Purpose To provide a comprehensive and up-to-date overview focusing on the extent of lymphatic transport of drugs following intestinal absorption and to summarize available data on the impact of molecular weight, lipophilicity, formulation and prandial state. Methods Literature was searched forin vivostudies quantifying extent of lymphatic transport of drugs after enteral dosing. Pharmacokinetic data were extracted and summarized. Influence of molecular weight, log P, formulation and prandial state was analyzed using relative bioavailability via lymph (F-RL) as the parameter for comparison. The methods and animal models used in the studies were also summarized. Results Pharmacokinetic data on lymphatic transport were available for 103 drugs. Significantly higher F-RL[median (IQR)] was observed in advanced lipid based formulations [54.4% (52.0)] and oil solutions [38.9% (60.8)] compared to simple formulations [2.0% (27.1)],p < 0.0001 andp = 0.004, respectively. Advanced lipid based formulations also provided substantial F(RL)in drugs with log P < 5, which was not observed in simple formulations and oil solutions. No relation was found between F(RL)and molecular weight. There were 10 distinct methods used forin vivotesting of lymphatic transport after intestinal absorption so far. Conclusion Advanced lipid based formulations provide superior ability to increase lymphatic absorption in drugs of various molecular weights and in drugs with moderate to low lipophilicity.

关键词： beta-carotene emulsion   beta-lactoglobulin   chitosan-ferulic acid conjugate   laccase induction   physicochemical stability  

摘要： The purpose of the present work is to fabricate emulsions with excellent stability to deliver beta-carotene using a novel biomacromolecule. beta-Lactoglobulin-ferulic acid-chitosan ternary conjugate (BFCC), which was synthesized based on the carbodiimide-mediated coupling reaction and laccase induction, was confirmed by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectra. Also, BFCC was used to stabilize beta-carotene emulsions. The results indicated that the concentration of BFCC affected the physical stability of beta-carotene emulsions. Compared with the emulsions stabilized by beta lactoglobulin (beta-LG), chitosan-ferulic acid conjugate (CFC), and beta-LG-CFC mixture (BFCM), the emulsion stabilized by BFCC exhibited better stability under various environmental stresses. Moreover, the emulsion stabilized by BFCC had higher beta-carotene retention during storage at 25 and 55 degrees C or under ultraviolet (UV) light exposure. The knowledge acquired in the current research offered an effective way to develop novel biomacromolecular emulsifiers and could find potential in fabricating delivery systems for bioactive compounds with markedly enhanced physiochemical properties.

关键词： Polyaniline   UV curing   Acrylic conducting composite   3D printing   Vat polymerization  

摘要： The design of novel photocurable conducive acrylic composites demands thorough research to find appropriate balance between the relative concentrations of monofunctional/ multifunctional monomers, photoinitiators and conducive filler, besides adjusting polymerization conditions. Likewise, when an intrinsically conducive polymer such as polyaniline (PANI) is selected as conducive filler, the homogeneous distribution of its nanometric aggregates is essential to prevent heterogeneous curing due to its strong UV absorption. In this work, the influence of PANI-HCl on the physical properties of acrylic composites based on Ethyleneglycolphenylether acrylate (EGPEA) and Diphenyl(2,4,6-trimethylbenzoyephosphine oxide (TPO), photoinitiator, was examined in the frame-work of the percolation model. Rheological testing combined with Scanning Electron Microscopy (SEM) were used for efficient control of the filler dispersion in order to better understand the electrical conductivity-structure behaviour. Infrared Spectroscopy probed the degree of monomer conversion and the filler interaction with the polymer matrix, whereas the thermal properties were evaluated with the aim of establishing the maximum working temperatures. Above the percolation threshold, the formulation with 4.8 wt% PANI was selected as the most suitable composition achieving maximum conductivity (10(-3) S cm(-1)) at the lowest PANI content. The problem of excessive aggregation of PANI clusters was tackled by the addition of a 15 wt% of the reactive diluent 1,6-hexanediol diacrylate (HDODA) to the previous formulation. The outcomes were improved dispersion and better integration of PANI nanorods within the acrylic matrix plus a smoother film surface, while retaining high electrical conductivity. The viscosity of the selected prepolymer formulations and penetration depth of UV photons gave encouraging results for the use of the developed compositions as anticorrosion coatings, digital light processing (DLP) or piezo

关键词： enzymatic esterification   diglycerides   molecular distillation   deodorization   silica gel column chromatography   acylglycerol composition   structured lipid  

摘要： Medium-chain diacylglycerol (MCD), medium-long-chain diacylglycerol (MLCD), and long-chain diacylglycerol (LCD) were prepared through enzymatic esterification using different conditions at temperatures of 55-70 degrees C and reaction times of 1.5-5 h and in the presence of 5-6% Novozym 435. Subsequently, purification was performed using three different techniques, namely, molecular distillation (MD), deodorization (DO), and silica gel column chromatography (SGCC). Variations in terms of the physicochemical and thermodynamic properties, crystallization properties, and kinetics of the diacylglycerols (DAGs) before and after purification were determined. Irrespective of the DAG chain lengths, SGCC was able to produce samples with high DAG purity (96-99 wt %), followed by MD (58-79 wt %) and DO (39-59 wt %). A higher 1,3-DAG/1,2-DAG ratio was recorded for all samples, with the highest ratio recorded for SGCC purified samples. Regardless of the purification techniques used, the solid fat content (SFC) profiles of crude samples with steep curves were altered post-purification, showing a gradual increment in SFC along with increasing temperature. Modification of the Avrami constant and coefficient suggested the modification of the crystal growth mechanism post-purification. Crystallization and melting temperatures of products with a higher DAG purity were shifted to a higher temperature region. Variations were also reflected in terms of the crystal polymorphism, whereby the alpha and beta' crystals transitioned into the more stable beta form in purified samples accompanied by modification in the microstructures and crystal sizes. However, there was insignificant change in the morphology of MLCD crystal after purification, except for the decrease in crystal sizes. In conclusion, synthesis of MCD, MLCD, and LCD comprising different DAG purities had distinctive SFC profiles, thermodynamic properties, crystallization kinetics, and crystal morphologies, which can be further inc

关键词： Microbial bio-fertilizers   Azotobacter chroococum   Azotobacter vinelandii   irrigation level   aggregate stability   soil fertility   eggplant  

摘要： The aims of this research were to investigate the effects of microbial bio-fertilizer (BF) application on physicochemical properties of sandy-clay-loam (SCL) soil under three different soil moisture regimes in greenhouse-grown eggplant (Solanum melongena L.). Correlations between the physicochemical soil properties in a greenhouse condition were determined. The microbial bio-fertilizers includedAzotobacter chroococumandAzotobacter vinelandii. Experiments were conducted in randomized plots design with three replications. Three different irrigation levels (100% (I100), 60% (I60) and 40% (I40) of field capacity-FC) were applied. Post-harvest soil samples were analyzed for soil physical and chemical characteristics. Bio-fertilizers had positive impacts on physicochemical soil properties. Bio-fertilizers accelerated mineralization of organic residues, thus improved the availability of macronutrients (N, P, K, Ca, and Mg) and micronutrients (Fe, Mn, Zn, and B). The highest total N value (0.143%) was observed in I100 treatment of bio-fertilizer (BF+I100) and the lowest total N (0.087%) was observed in I40 treatment without bio-fertilizer. Bio-fertilizers improved aggregate stability, total porosity, moisture-retention capacity and infiltration rate, and decreased bulk density of the soils. Bio-fertilizers increased water uptake and decreased drought susceptibility of the plants. It was concluded that bio-fertilizers could reliably be used to improve soil physical and chemical characteristics under different irrigation levels.