scholarly journals Formulation and optimization of astaxanthin nanoemulsions with marine phospholipids derived from large yellow croaker (Larimichthys crocea) roe

2021 ◽  
Vol 33 (3) ◽  
pp. 1-13
Author(s):  
Luyao Huang ◽  
Lingyun Zhang ◽  
Ruifen Li ◽  
Peng Liang

The aim of this work was to investigate the emulsifying capacity of marine phospholipids derived from large yellow croaker roe (LYCRPLs). Initially, conditions for preparing astaxanthin (1% w/w) nanoemulsions with LYCRPLs were optimized based on single-factor experiments, including homogenization pressure, homogenization cycle, emulsifier concentration and corn oil concentration via the response surface methodology. The optimal homogenization pressure was 60 MPa, the optimal number of homogenization cycles was nine, the optimal emulsifier concentration was 4.7%, and the optimal oil concentration was 20%. Under these conditions, the stability, particle size and polydispersity index of nanoemulsions were 0.018 ± 0.0016, 247 ± 4.5 nm and 0.215±0.019, respectively. The droplets of nanoemulsions were characterized by transmission electron microscopy, which revealed that all the droplets were more or less spherical and nonaggregated. In addition, the storage experiments indicated that the nanoemulsions were stable at different temperatures. Therefore, LYCRPLs could be explored as carriers for the delivery of insoluble bioactive compounds in the food industry.

2015 ◽  
Vol 60 (3) ◽  
pp. 2131-2137 ◽  
Author(s):  
M. Gruber ◽  
S. Ploberger ◽  
G. Ressel ◽  
M. Wiessner ◽  
M. Hausbauer ◽  
...  

Abstract The stability of austenite is one of the most dominant factors affecting the toughness properties of high Co-Ni steels such as Aermet 100 and AF1410. Thus, the aim of this work was to get a deeper understanding on the impact of combined heat and cryogenic treatment on the stability of retained and reverted austenite. In order to characterize the evolution of the phase fraction of austenite during tempering at different temperatures and times, X-ray diffraction analyses were carried out. The stability of austenite, which was formed during tempering, was analyzed with dilatometric investigations by studying the transformation behavior of the austenite during cooling from tempering temperature down to −100°C. Additionally, transmission electron microscopy investigations were performed to characterize the chemical composition and phase distribution of austenite and martensite before and after tempering.


2021 ◽  
Vol 2 ◽  
Author(s):  
Emanuele Smecca ◽  
Ajay Kumar Jena ◽  
Ioannis Deretzis ◽  
Salvatore Valastro ◽  
Salvatore Sanzaro ◽  
...  

Hybrid perovskites are one of the most popular materials nowadays due to their very exclusive properties. To mitigate costs, complexity, and environmental impact, in this work, we have prepared methylammonium lead iodide (MAPbI3) films by a two-step Low-Vacuum Proximity-Space-Effusion (LV-PSE). The LV-PSE method exploits the low vacuum and the short diffusion path from the precursor source to have high thermal energy and partial pressure of the sublimated species close to the substrate. To this aim, the substrate is located at a medium distance (∼2 cm) from the melting pots in a low-vacuum chamber at ∼4 × 10−2 mbar. In the first step, a PbI2 film is deposited on a substrate; in the second step, the conversion into MAPbI3 occurs via an adsorption-incorporation-migration mechanism through the evaporation of methylammonium iodide (MAI) reagents. To exploit the potential of the conversion reaction, 190 nm MAPbI3 layers are deposited on TiO2 substrates. The layers were characterized in terms of crystal structure by X-ray diffraction (XRD) analyses, which showed the exclusive presence of MAPbI3 confirming the complete conversion of the PbI2 film. Scanning Electron Microscopy (SEM) analyses revealed a flat uniform pinhole-free coverage of the substrates and good conformational coverage of the TiO2 underlayer. Transmission Electron Microscopy (TEM) analyses addressed the formation of the tetragonal phase and the absence of the amorphous phase in the film. Spectroscopic ellipsometry (SE) analyses were used to explore the optical properties and the stability of the MAPbI3 layer at different temperatures and ambient conditions. As proof of concept, solar cell architectures were prepared using TiO2 as Electron Transporting Layer (ETL), Spiro-OMeTAD as Hole Transporting Layer (HTL), and Au as a contact to exploit the new up-scalable and clean deposition method. Using just ∼190 nm thick layers, the best efficiency reached with this architecture was 6.30%.


Author(s):  
S. Shinozaki ◽  
J. W. Sprys

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.


Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.


1997 ◽  
Vol 3 (S2) ◽  
pp. 51-52
Author(s):  
B.J. Cornell ◽  
A. Singh ◽  
I. Chu

Polyhalogenated aromatic compounds such as polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins (PCDDs) continue to be environmental contaminants because of their bioaccumulation in the food chain and high resistance to biodegradation. The current study was undertaken to determine if a mixture of PCB congeners (WHO-IPCS) were interactive with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in producing morphological changes in the rat liver. Both compounds are known to produce a broad range of biochemical and morphological alterations including enzyme induction.Groups (N=5) of female Sprague-Dawley rats were administered TCDD (0, 2.5, 25, 250, 1000 ng/kg bw/day) or PCB (0, 2, 20 μg/kg bw/day) alone, or in combination with each concentration of both compounds. Incorrect concentrations were published in a previous abstract. The test substance was mixed with corn oil and given by gavage at 2 ml/kg daily for 28 days. At the end of the experiment, the rats were killed and liver samples were prepared for transmission electron microscopy.


Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1089
Author(s):  
Muhammad T. Sajjad ◽  
Ashu K. Bansal ◽  
Francesco Antolini ◽  
Eduard Preis ◽  
Lenuta Stroea ◽  
...  

Many displays involve the use of color conversion layers. QDs are attractive candidates as color converters because of their easy processability, tuneable optical properties, high photoluminescence quantum yield, and good stability. Here, we show that emissive QDs with narrow emission range can be made in-situ in a polymer matrix, with properties useful for color conversion. This was achieved by blending the blue-emitting pyridine based polymer with a cadmium selenide precursor and baking their films at different temperatures. To achieve efficient color conversion, blend ratio and baking temperature/time were varied. We found that thermal decomposition of the precursor leads to highly emissive QDs whose final size and emission can be controlled using baking temperature/time. The formation of the QDs inside the polymer matrix was confirmed through morphological studies using atomic force microscopy (AFM) and transmission electron microscopy (TEM). Hence, our approach provides a cost-effective route to making highly emissive color converters for multi-color displays.


Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1637
Author(s):  
Yunjiao Zhao ◽  
Rui Liu ◽  
Cuiping Qi ◽  
Wen Li ◽  
Mohamed Rifky ◽  
...  

The active components in garlic essential oil are easily degradable, which limits its application in the food industry. Vegetable oils (VOs) were used to improve the stability of garlic essential oil (GEO) emulsion. The volatile compounds of GEO and its mixtures with vegetable oils (VOs), including corn oil (CO), soybean oil (SO), and olive oil (OO) indicated that GEO-VO mixtures had a higher percentage of Diallyl disulfide and Diallyl trisulfide than pure GEO. Adding an appropriate amount of VOs promoted the GEO emulsion (whey protein concentrate and inulin as the wall materials) stability in order of CO > SO > OO. Evaluation of the encapsulation efficiency, controlled release, and antimicrobial activity of GEO-VO microcapsules showed that the GEO was successfully entrapped and slowly released with active antibacterial activities on both E. coli and S. aureus. Collectively, these results implied that VOs, especially for 20% CO, improved the stability of GEO emulsions and the encapsulation efficiency of GEO microcapsules. The mechanism might be related to (1) the regulating effect of density difference between oil and water phases on prevention to gravitational separation, (2) the promotion to the compatibility of GEO and VOs to inhibit the phase separation caused by Ostwald ripening.


Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.


1971 ◽  
Vol 125 (4) ◽  
pp. 1009-1018 ◽  
Author(s):  
R. E. Chambers ◽  
J. R. Clamp

The stability of monosaccharides in methanolic hydrochloric acid of different strengths and at different temperatures was determined. They are generally stable for 24h in methanolic 1m- and 2m-hydrochloric acid at both 85°C and 100°C, but undergo considerable destruction in methanolic 4m- and 6m-hydrochloric acid at 100°C. Analysis of glycopeptides and oligosaccharides of known composition showed that release of carbohydrate was complete within 3h in methanolic 1m-hydrochloric acid at 85°C. Removal of methanolic hydrochloric acid by rotary evaporation resulted in considerable losses of monosaccharides, which could be prevented by prior neutralization. Methanolysis caused extensive de-N-acetylation of acetamidohexoses, so that a re-N-acetylation step is necessary in the analytical procedure. The addition of acetic anhydride for this purpose also prevented loss of internal standard by adsorption on the insoluble silver salts used in neutralization. Several trimethylsilylating agents were studied and suitable conditions are recommended. The effects on the analytical system of water and some common organic and inorganic contaminants are assessed.


Author(s):  
Josep Miquel Bauça ◽  
Andrea Caballero ◽  
Carolina Gómez ◽  
Débora Martínez-Espartosa ◽  
Isabel García del Pino ◽  
...  

AbstractObjectivesThe stability of the analytes most commonly used in routine clinical practice has been the subject of intensive research, with varying and even conflicting results. Such is the case of alanine aminotransferase (ALT). The purpose of this study was to determine the stability of serum ALT according to different variables.MethodsA multicentric study was conducted in eight laboratories using serum samples with known initial catalytic concentrations of ALT within four different ranges, namely: <50 U/L (<0.83 μkat/L), 50–200 U/L (0.83–3.33 μkat/L), 200–400 U/L (3.33–6.67 μkat/L) and >400 U/L (>6.67 μkat/L). Samples were stored for seven days at two different temperatures using four experimental models and four laboratory analytical platforms. The respective stability equations were calculated by linear regression. A multivariate model was used to assess the influence of different variables.ResultsCatalytic concentrations of ALT decreased gradually over time. Temperature (−4%/day at room temperature vs. −1%/day under refrigeration) and the analytical platform had a significant impact, with Architect (Abbott) showing the greatest instability. Initial catalytic concentrations of ALT only had a slight impact on stability, whereas the experimental model had no impact at all.ConclusionsThe constant decrease in serum ALT is reduced when refrigerated. Scarcely studied variables were found to have a significant impact on ALT stability. This observation, added to a considerable inter-individual variability, makes larger studies necessary for the definition of stability equations.


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