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1.
Food Res Int ; 188: 114531, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38823850

RESUMEN

Different emulsion gel systems are widely applied to deliver functional ingredients. The effects and mechanisms of ultrasound-assisted emulsification (UAE) treatment and carboxymethyl cellulose (CMC) modifying the curcumin delivery properties and in vitro digestibility of the myofibrillar protein (MP)-soybean oil emulsion gels were investigated. The rheological properties, droplet size, protein and CMC distribution, ultrastructure, surface hydrophobicity, sulfhydryl groups, and zeta potential of emulsion gels were also measured. Results indicate that UAE treatment and CMC addition both improved curcumin encapsulation and protection efficiency in MP emulsion gel, especially for the UAE combined with CMC (UAE-CMC) treatment which encapsulation efficiency, protection efficiency, the release rate, and bioaccessibility of curcumin increased from 86.75 % to 97.67 %, 44.85 % to 68.85 %, 18.44 % to 41.78 %, and 28.68 % to 44.93 % respectively. The protein digestibility during the gastric stage was decreased after the CMC addition and UAE treatment, and the protein digestibility during the intestinal stage was reduced after the CMC addition. The fatty acid release rate was increased after CMC addition and UAE treatment. Apparent viscosity, storage modulus, and loss modulus were decreased after CMC addition while increased after UAE and UAE-CMC treatment especially the storage modulus increased from 0.26 Pa to 41 Pa after UAE-CMC treatment. The oil size was decreased, the protein and CMC concentration around the oil was increased, and a denser and uniform emulsion gel network structure was formed after UAE treatment. The surface hydrophobicity, free SH groups, and absolute zeta potential were increased after UAE treatment. The UAE-CMC treatment could strengthen the MP emulsion gel structure and decrease the oil size to increase the curcumin delivery properties, and hydrophobic and electrostatic interaction might be essential forces to maintain the emulsion gel.


Asunto(s)
Carboximetilcelulosa de Sodio , Curcumina , Digestión , Emulsiones , Geles , Interacciones Hidrofóbicas e Hidrofílicas , Reología , Curcumina/química , Emulsiones/química , Carboximetilcelulosa de Sodio/química , Geles/química , Proteínas Musculares , Aceite de Soja/química , Viscosidad , Tamaño de la Partícula , Miofibrillas/química , Miofibrillas/metabolismo , Ondas Ultrasónicas
2.
J Agric Food Chem ; 72(4): 2178-2192, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38259150

RESUMEN

In our previous study, yeast-derived peptide Tyr-Pro-Leu-Pro (YPLP) was found to prolong treadmill time and relieve muscle fatigue in ICR mice. The present study aimed to further investigate the antifatigue mechanism of YPLP. Three doses of YPLP (10, 25, and 50 mg/kg·d) were given to exercise mice for 4 weeks. Results showed that YPLP reduced the oxidative response via the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway and promoted energy metabolism through the AMP-activated protein kinase (AMPK) pathway. Label-free proteomics results showed that 81 differential abundance proteins (DAPs) were regulated by high-dose YPLP. These DAPs belonged to proteasome, mitochondrial, and muscle proteins. YPLP was mainly involved in proteasome, aminoacyl-tRNA biosynthesis, focal adhesion, and MAPK signal pathways to enhance muscle endurance. Furthermore, real-time quantitative PCR and Western blotting results proved that YPLP upregulated Psmd14 expression and downregulated p38 MAPK expression. Overall, this study revealed the mechanism behind YPLP to alleviate exercise fatigue.


Asunto(s)
Dipéptidos , Complejo de la Endopetidasa Proteasomal , Proteómica , Animales , Ratones , Complejo de la Endopetidasa Proteasomal/genética , Ratones Endogámicos ICR , Proteínas Quinasas Activadas por AMP/genética , Proteínas Quinasas Activadas por AMP/metabolismo
3.
Ultrason Sonochem ; 101: 106697, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37984208

RESUMEN

In this study, the effects of ultrasound-assisted enzymatic hydrolysis on the extraction of anti-inflammatory peptides from porcine bone collagen were investigated. The results showed that ultrasound treatment increased the content of α-helix while decreased ß-chain and random coil, promoted generation of small molecular peptides. Ultrasound-assisted enzymatic hydrolysis improved the peptide content, enhanced ABTS+ radical scavenging and ferrous ion chelating ability than non-ultrasound group. At the ultrasonic power of 450 W (20 min), peptides possessed significant anti-inflammatory activity, where the releasing of interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) was all suppressed in lipopolysaccharide (LPS) induced RAW264.7 cells. After the analysis with LC-MS/MS, eight peptides with potential anti-inflammatory activities were selected by the PeptideRanker and molecular docking. In general, the ultrasound-assisted enzymatic hydrolysis was an effective strategy to extract the bioactive peptides from porcine bone, and the inflammatory regulation capacity of bone collagen sourced peptides was firstly demonstrated.


Asunto(s)
Péptidos , Espectrometría de Masas en Tándem , Animales , Porcinos , Hidrólisis , Cromatografía Liquida , Simulación del Acoplamiento Molecular , Péptidos/farmacología , Péptidos/química , Antioxidantes/química , Colágeno/farmacología , Colágeno/química , Antiinflamatorios/farmacología , Antiinflamatorios/química
4.
J Agric Food Chem ; 71(42): 15522-15537, 2023 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-37807259

RESUMEN

In our previous study, the antioxidant peptides (XHY69AP, AP-D, YPLP, and AGPL) were obtained from potential probiotic yeast (Yamadazyma triangularis XHY69), which was selected by our lab from dry-cured ham. This work aimed to explore the effects of yeast-derived peptides on skeletal muscle function and muscle fatigue. Results showed that yeast-derived peptides up-regulated slow-twitch fiber expression and down-regulated fast-twitch fiber expression in C2C12 cells (p < 0.05). The peptides improved mitochondrial membrane potential, adenosine triphosphate generation, and expression of cytochrome-relative genes, thus promoting mitochondrial function. Among these peptides, YPLP up-regulated the relative gene expression of the AMP-activated protein kinase (AMPK) pathway and activated AMPK by phosphorylation. Moreover, YPLP could prolong treadmill time, increase muscle and liver glycogen contents, reduce lactic acid and urea nitrogen contents, and alleviate muscle tissue injury in ICR exercise mice. These results demonstrate that yeast-derived peptides could change the muscle fiber composition, improve muscle function, and relieve muscle fatigue.


Asunto(s)
Proteínas Quinasas Activadas por AMP , Saccharomyces cerevisiae , Ratones , Animales , Saccharomyces cerevisiae/metabolismo , Ratones Endogámicos ICR , Proteínas Quinasas Activadas por AMP/genética , Proteínas Quinasas Activadas por AMP/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo
5.
Ultrason Sonochem ; 98: 106490, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37343395

RESUMEN

Our previous study has found that ultrasonic application on raw meat could improve the flavor of unsmoked bacon. For comprehensively evaluating the impacts of ultrasonic pretreatment (0, 250, 500 or 750 W, 20 kHz) on the overall quality of unsmoked bacon during processing, the following indicators were determined including salt and water content, pH, shear force, color, water distribution, texture and myofibril microstructure. Results manifest that ultrasonic pretreatment could significantly improve the salt and water content, pH and redness of unsmoked bacon. The water retention capacity was obviously enhanced by ultrasonic pretreatment proved by increased immobile water and decreased free water. Meanwhile, the shear force, the hardness and the chewiness were notably ameliorated after ultrasonic pretreatment, suggesting a better tenderness verified by the observation results of transmission electron microscope. However, no significant differences were found on the brightness, yellowness, springiness, cohesiveness and resilience of unsmoked bacon after ultrasonic pretreatment. Consequently, ultrasound could be considered as a potential tool for the overall-quality improvement of unsmoked bacon.


Asunto(s)
Carne de Cerdo , Animales , Ultrasonido , Carne de Cerdo/análisis , Culinaria , Cloruro de Sodio Dietético , Concentración de Iones de Hidrógeno , Color
6.
Carbohydr Polym ; 309: 120679, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-36906362

RESUMEN

Improving the qualities of vegetable oil replaced animal fat meat products is particularly fascinating for the development of healthy meat products. This work was designed to investigate the effects of different carboxymethyl cellulose (CMC) concentrations (0.01 %, 0.05 %, 0.1 %, 0.2 %, and 0.5 %) on the emulsifying, gelation, and digestive properties of myofibrillar protein (MP)-soybean oil emulsions. The changes in MP emulsion characteristics, gelation properties, protein digestibility, and oil release rate were determined. Results demonstrated that CMC addition decreased the average droplet size and increased the apparent viscosity, storage modulus, and loss modulus of MP emulsions, and a 0.5 % CMC addition significantly increased the storage stability during 6 weeks. Lower CMC addition (0.01 % to 0.1 %) increased the hardness, chewiness, and gumminess of emulsion gel especially for the 0.1 % CMC addition, while higher CMC (0.5 %) content decreased the texture properties and water holding capacity of emulsion gels. The addition of CMC decreased protein digestibility during the gastric stage, and 0.01 % and 0.05 % CMC addition significantly decreased the free fatty acid release rate. In summary, the addition of CMC could improve the stability of MP emulsion and the texture properties of the emulsion gels, and decrease protein digestibility during the gastric stage.


Asunto(s)
Carboximetilcelulosa de Sodio , Aceite de Soja , Animales , Emulsiones , Proteínas Musculares , Geles
7.
Antioxidants (Basel) ; 12(3)2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36978854

RESUMEN

This present study aimed to investigate the effects of various cooking times (1 h, 1.5 h, 2 h, 2.5 h, named as JHBP-1, JHBP-1.5, JHBP-2, JHBP-2.5) on the antioxidant activity and peptide profile of Jinhua ham broth peptides (JHBP). The peptides extracted from uncooked ham were used as an uncooked group with the name of JHBP-0. The results revealed that the antioxidant efficacy in the four cooked groups changed dramatically compared to JHBP-0. After cooking, the DPPH radical scavenging activity, hydroxyl radical scavenging activity and superoxide anion radical scavenging activity decreased, except for the Fe2+ chelation and ABTS+ scavenging capacity which increased significantly. However, the cooked groups still showed a strong antioxidant capacity. In particular, the superoxide anion radical scavenging ability and the Fe2+ chelation action were significantly stronger compared to glutathione (GSH) and butylated hydroxytoluene (BHT) (p < 0.05). JHBP-1.5 also displayed stronger antioxidant capacity than the other three cooked groups, and its secondary structure and mass distribution changed significantly after cooking, specifically with an increased proportion of helix and <1 kDa peptides. Moreover, the constitution of free amino acids (FAAs) and the types of peptides released in the broth increased significantly with a longer cooking time. In total, 1306 (JHBP-0), 1352 (JHBP-1), 1431 (JHBP-1.5), 1500 (JHBP-2), and 1556 (JHBP-2.5) peptide sequences were detected using LC-MC/MC. The proportion of <1 kDa peptides also gradually increased as the cooking time extended, which is consistent with the molecular weight distribution measurements.

8.
Antioxidants (Basel) ; 11(10)2022 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-36290693

RESUMEN

The aim of this study was to select potential probiotic yeasts from dry-cured Xuanwei ham and investigate yeast-derived antioxidant peptides. The results showed that two strains (XHY69 and XHY79) were selected as potential probiotic yeasts and identified as Yamadazyma triangularis. The two yeasts showed tolerance under pH 2.5 and 1% bile salt, in addition to protease activity, auto-aggregation, antibacterial, and antioxidant activities. The peptide fraction (MW < 3 kDa) isolated from XHY69 fermentation broth, named XHY69AP, showed higher radical scavenging activities than glutathione at a concentration of 4.5 mg/mL (p < 0.05). The fraction (AP-D10) was purified from XHY69AP by gel filtration chromatography and reversed-phase high performance liquid chromatography, and then further identified by a UHPLC-LTQ-Orbitrap mass spectrometer. The molecular weight of all 55 purified sequences was distributed between 0.370 and 0.735 kDa. Among these seven novel peptides, Tyr-Pro-Leu-Pro (YPLP), Ala-Gly-Pro-Leu (AGPL), Gly-Pro-Phe-Pro (GPFP), and Ala-Pro-Gly-Gly-Phe (APGGF) were identified. All sequences were abundant in hydrophobic amino acids, especially proline residue. Among these novel peptides, YPLP possessed the highest ABTS scavenging rate (75.48%). The present work selects two new probiotic potential yeasts from dry-cured Xuanwei ham that are effective to yield novel antioxidant peptides.

9.
Front Nutr ; 9: 980204, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36118776

RESUMEN

This study aimed to investigate the effect of oxidized beef protein on colon health. C57BL/6 mice were fed diets containing in vitro oxidized beef protein (carbonyl content 5.83/9.02 nmol/mg protein) or normal beef protein (control group, carbonyl content 2.27 nmol/mg protein) for 10 weeks. Histological observations showed that oxidized beef protein diet induced notable inflammatory cell infiltrations in colon. The analysis of high-throughput sequencing indicated oxidized beef protein largely altered the composition of gut microbiota (GM) by increasing proinflammatory bacteria (Desulfovibrio, Bacteroides, Enterorhabdus) while reducing beneficial bacteria (Lactobacillus, Akkermansia). In addition, oxidized beef protein remarkably increased protein fermentation in the colon, which was evidenced by the elevated i-butyrate, i-valerate, and ammonia levels in feces. Furthermore, consuming oxidized beef protein destroyed colon barrier functions by decreasing tight junction proteins expression. These changes in colonic ecosystem activated the proinflammatory pathway of lipopolysaccharide/toll-like receptor-4/nuclear factor kappa B (LPS/TLR-4/NF-κB), eventually leading to colonic inflammatory damage in mice. Taken together, these results imply that consuming oxidized beef protein detrimentally regulates GM and impairs colon health.

10.
Foods ; 11(15)2022 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-35892761

RESUMEN

Lipid oxidation and protein oxidation occur side by side in meat. Here, the effect of malondialdehyde (MDA), the major product of lipid oxidation, on the digestibility of beef myofibrillar proteins (MP) was studied. MP samples were incubated with 0, 0.1, 0.3, 0.5, and 0.7 mM MDA at 4 °C for 12 h and then subjected to in vitro gastrointestinal digestion. The result showed that MDA remarkably reduced the digestibility of MP (p < 0.05). MDA treatments significantly increased carbonyl and Schiff base contents in MP (p < 0.05). The microstructure observed by atomic force microscopy showed that MDA treatments resulted in the aggregation of MP. Non-reducing and reducing electrophoresis suggested the aggregation was mainly caused by covalent bonds including disulfide bond and carbonyl−amine bond. Proteomics analysis proved that the myosin tail was the main target of MDA attack, meanwhile, lysine residues were the major modification sites. Taken together, the above results imply that MDA induces protein oxidation, aggregation, and blockage of hydrolysis sites, consequently leading to the decrease in both gastric and gastrointestinal digestibility of MP.

11.
Front Psychol ; 13: 934012, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35795452

RESUMEN

To understand the mechanism of boundary personnel opportunistic behaviors in collaborative R&D projects to reduce the risk of companies suffering from opportunism in collaboration. This study is conducted based on the context of collaborative R&D in the equipment manufacturing industry in Northeast China. This research mainly explored the mechanism of boundary personnel opportunistic intentions. Drawing on the theory of reasoned action (TRA), this study investigated the relationship between boundary personnel Guanxi, organizational loyalty, opportunistic attitudes, subjective norms, and intentions. In addition, this research examined the moderating role of the degree of dependence on the collaborator. In total, 524 valid questionnaires were finally collected. The data analysis results suggested that Guanxi inhibits opportunistic attitudes and subjective norms. Organizational loyalty promotes opportunistic attitudes and subjective norms. Opportunistic attitudes and subjective norms positively predict intentions. Opportunistic attitudes mediate between organizational loyalty and opportunistic intentions. Opportunistic subjective norms mediate between Guanxi and opportunistic intentions. Opportunistic subjective norms also mediate between organizational loyalty and opportunistic intentions. Dependence on the collaborator positively moderates the relationship between opportunistic attitudes and intentions. Therefore, it can be argued that in collaborative R&D in the equipment manufacturing industry, the corporate could stimulate boundary personnel to build good Guanxi to eliminate opportunism. At the same time, companies should lead employees to show loyalty properly, which opportunism is not wise in collaborative R&D. Finally, enterprises should objectively understand and evaluate the dependence relationship between the two partners in collaborative R&D to adopt the right strategy.

12.
Front Psychol ; 13: 851780, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35310228

RESUMEN

This study constructs a mechanism of the influence of Guanxi between boundary spanners on opportunistic behaviors in collaborative innovation projects based on the theory of reasoned action model. The study conducts a survey in the automobile industry in Changchun, Jilin Province, China, and analyzes the research data using the structural equation model. The findings show that Guanxi has a negative an significant influence on opportunistic behavior attitudes and subjective norms., Guanxi has the greater influence on subjective norms than attitudes. Then, opportunistic behavior attitudes and subjective norms positively influence intentions. The influence of subjective norms is stronger. The attitudes and subjective norms of opportunistic behaviors also play mediation roles. Furthermore, opportunistic behavior intentions have a positive and significant influence on behaviors. In short, the study's findings reveal a mechanism of Guanxi between boundary spanners influencing opportunistic behaviors of boundary spanners. It also provides a reference for corporate managers to govern opportunistic behaviors of collaborator while inhabiting opportunistic behaviors of their own boundary spanners.

13.
Anim Biosci ; 34(10): 1695-1704, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33705628

RESUMEN

OBJECTIVE: The aim of this work was to assess the effect of ergothioneine (ESH)-enriched mushroom extract on oxidative stability, volatile compounds, and sensory quality of emulsified sausage. METHODS: The ESH content was determined by high performance liquid chromatography. The antioxidant activity of Flammulina velutipes (F. velutipes) extract was determined through radical-scavenging activity of 1,1 diphenyl-2-picryl-hydrazyl, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl radicals. Four different groups of emulsified sausage were manufactured: control, no antioxidants; BHA, 0.01% butylated hydroxyanisole; EEME, 0.8% ESH-enriched mushroom (F. velutipes) extract; AE, 0.012% authentic ESH, after storage for 14 days (at 4°C), the quality of sausage including oxidative stability (2-thiobarbituric acid reactive substances and protein carbonyls content), volatile compounds and sensory quality were studied. RESULTS: It was demonstrated that adding ESH-enriched F. velutipes extract to sausage could effectively prevent lipid and protein oxidation, and its efficacy was equivalent with 0.01% BHA. During meat processing, the ESH mainly contributed to the antioxidative activity of F. velutipes extract. The flavor and sensory attributes of emulsified sausage were improved through adding ESH-enriched F. velutipes extract. CONCLUSION: Accordingly, the extract of F. velutipes contained high-level of ESH and could be a good antioxidant candidate for processed meat production.

14.
ACS Appl Mater Interfaces ; 12(47): 53519-53527, 2020 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-33174735

RESUMEN

Photoluminescence perovskite nanocrystals (NCs) have shown significant potential in optoelectronic applications in view of their narrow band emission with high photoluminescence quantum yields and color tunability. The main obstacle for practical applications is to obtain high durability against an external environment. In this work, a low temperature (50 °C) plasma-enhanced atomic layer deposition (PE-ALD) protection strategy was developed to stabilize CsPbBr3 NCs. Silica was employed as the encapsulation layer because of its excellent light transmission performance and water corrosion resistance. The growth mechanism of inorganic SiO2 via PE-ALD was investigated in detail. The Si precursor bis(diethylamino)silane (BDEAS) reacted with the hydroxyl groups (-OH) and thereby initiated the subsequent silica growth while having minimal influence to the organic ligands and did not cause PL quenching. Subsequently, O2 plasma with high reactivity was used to oxidize the amine ligands of the BDEAS precursor while did not etch the NCs. The obtained CsPbBr3 NCs/SiO2 film exhibited exceptional stability in water, light, and heat as compared to the pristine NC film. Based on this method, a white light-emitting diode with improved operational stability was successfully fabricated, which exhibited a wide color gamut (∼126% of the National Television Standard Committee). Our work successfully demonstrates an efficient protection scheme via the PE-ALD method, which extends the applied range of other materials for stabilization of perovskite NCs through this approach.

15.
Inorg Chem ; 59(7): 4483-4492, 2020 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-32174112

RESUMEN

Three classical Fe-MOFs, viz., MIL-100(Fe), MIL-101(Fe), and MIL-53(Fe), were synthesized to serve as platforms for the investigation of structure-activity relationship and catalytic mechanism in the selective conversion of H2S to sulfur. The physicochemical properties of the Fe-MOFs were characterized by various techniques. It was disclosed that the desulfurization performances of Fe-MOFs with well-defined microstructures are obviously different. Among these, MIL-100(Fe) exhibits the highest catalytic performance (ca. 100% H2S conversion and 100% S selectivity at 100-180 °C) that is superior to that of commercial Fe2O3. Furthermore, the results of systematic characterization and DFT calculation reveal that the difference in catalytic performance is mainly because of discrepancy in the amount of Lewis acid sites. A plausible catalytic mechanism has been proposed for H2S selective conversion over Fe-MOFs. This work provides critical insights that are helpful for rational design of desulfurization catalysts.

16.
J Chem Inf Model ; 60(5): 2614-2625, 2020 05 26.
Artículo en Inglés | MEDLINE | ID: mdl-31990536

RESUMEN

For the past decade, cryogenic electron microscopy (cryo-EM) has become an important technology to determine three-dimensional (3D) structures of biomacromolecules. Many software tools have been developed for cryo-EM image processing and 3D reconstruction, covering various computational tasks in cryo-EM data analysis. Despite the recent progress, most of these software tools focus on a single task, such as automatic particle picking or image clustering, whereas software packages covering the whole pipeline of cryo-EM data processing are still few. In this study, we developed a fully automatic single-particle reconstruction and analysis toolkit for cryo-EM data, named SPREAD, which integrates 2D image classification, 3D initial model generation, model selection, and 3D refinement. In SPREAD, we adopt our previously proposed network-based clustering algorithm for 2D image classification, NCEM, and the reference-free resolution measurement method SRes to realize the automatic model ranking and selection procedure. Projection orientation assignment is one of the key steps in initial model generation and 3D refinement. In SPREAD, we use the network-based image similarity metric and introduce a new probabilistic-based orientation searching method, named peak finding, to enhance assignment of the projection orientations. For dealing with both the particle images and projection images in the 3D refinement using SPREAD, we build a mixture image network containing both of these types of images on the basis of the peak-finding results, and then similarities for node pairs are recomputed by a superposed random walk on the network. SPREAD achieves a fully automatic workflow in which nearly no expert domain knowledge and interactive manual operation are involved. Our software can accessed for free at http://www.csbio.sjtu.edu.cn/bioinf/SPREAD/ for academic use.


Asunto(s)
Imagenología Tridimensional , Imagen Individual de Molécula , Algoritmos , Microscopía por Crioelectrón , Procesamiento de Imagen Asistido por Computador
17.
Sci Bull (Beijing) ; 65(8): 678-688, 2020 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-36659137

RESUMEN

As an ultrathin film preparation method, atomic layer deposition (ALD) has recently found versatile applications in fields beyond semiconductors, such as energy, environment, catalysis and so on. The design, preparation and characterization of thin film applied in the emerging fields have attracted great interests. The development of ALD technique on particles opens up a broad horizon in the advanced nanofabrication. Pioneering applications are exploring conformal coating, porous coating and selective surface modification of nanoparticles. Conformal encapsulation of particles is a major application to protect materials with ultrathin films from being eroded by the external environment while keeping the original properties of the primary particles. Porous coating has been developed to simultaneously expose the particles' surface and provide nanopores, which is another important method that demonstrates its advantages in modification of electrode materials, catalysis and energy applications, etc. Selective ALD takes the method forward in order to precisely control the directionality of decoration sites on the particles and selectively passivate undesired facets, sites, or defects. Such methods provide practical strategies for atomic scale and precise surface functionalization on particles and greatly expand its potential applications.

18.
J Environ Health Sci Eng ; 17(1): 135-140, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31321041

RESUMEN

BACKGROUND: Aniline compounds are widely applied as important chemical raw materials. However, they are so toxic and harmful to humans and environment that they need to be removed by an effective and economic approach, such as enzymatic reaction, which is in line with contemporary green development concepts. METHODS: The effects of major factors, such as temperature, reaction time, concentration of laccase and the initial concentration of substrate on the removal of substrate were investigated by OFAT approach. After simulated wastewater is treated with enzymes, aniline concentration was determined by N-(1-Naphthyl)ethylene-diamine dihydrochloride spectrophotometric method. Concentration of o-phenylenediamine was determined by ferric ammonium alum spectrophotometric method. RESULTS: For the removal of aniline, the optimum conditions were as follows: 50 °C, initial aniline concentration of 80 mg/L and laccase concentration of 1 g/L. In this case, the total removal of aniline reached 97.1% after 8 h, this also involves the volatilization of aniline itself. The optimum conditions of o-phenylenediamine were as follows: 50 °C, initial concentration of 100 mg/L and laccase concentration of 1 g/L. Under the above condition, the o-phenylenediamine could be removed completely after 60 min. CONCLUSION: The results show that the removal of aniline compounds by laccase from white-rot fungi has good effect and potential application prospect.

19.
Environ Sci Pollut Res Int ; 26(4): 3814-3822, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30539399

RESUMEN

Chitosan/Co-Fe-layered double hydroxides (CS/LDHs) were prepared by coprecipitation method, which is a kind of composite material with excellent properties. The structure of CS/LDHs was characterized by SEM, FTIR, and XRD, which proved that chitosan (CS) was successfully induced into hydrotalcite and CS/LDHs still possess the structural characteristics of hydrotalcite. The adsorption of 2,4-dichlorophenol (2,4-DCP) was studied with CS/LDHs and LDHs as adsorbent separately. The activity of immobilized laccase (L-CS/LDHs) with CS/LDHs as carrier is significantly better than that of the one (L-LDHs) using LDHs as carrier. Under the optimum conditions (pH = 6, 55 °C, 48 h), L-CS/LDHs exhibited better removal performance for 2,4-DCP (81.53%, 100 mg/L) than LDHs (63.55%); the removal of 2,4-DCP by L-CS/LDHs is excellent, exceeding 97% as its initial concentration below 60 mg/L. It includes the catalytic action of laccase and dechlorination of Fe3+ and Co2+, and the adsorption can be ignored under the optimal conditions. After 5 cycles, it maintained 67% (L-CS/LDHs) and 54% (L-LDHs) of the original removal.


Asunto(s)
Hidróxido de Aluminio/química , Quitosano/química , Clorofenoles/análisis , Cobalto/química , Contaminantes Ambientales/análisis , Hierro/química , Hidróxido de Magnesio/química , Adsorción , Enzimas Inmovilizadas/química , Lacasa/química
20.
Rev Sci Instrum ; 89(12): 123702, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30599563

RESUMEN

A dual chamber system integrated with atomic layer deposition (ALD) and atomic force microscopy (AFM) was developed for the successive monitoring of nanoparticles to thin film growth process. The samples were fabricated in the ALD chamber. A magnetic transmission rod enabled sample transferring between the ALD and the AFM test chambers without breaking the vacuum, avoiding possible surface morphology change when frequently varying the growth condition and oxidation under ambient condition. The sample transmission also avoids deposition and contamination on the AFM tip during the successive testing. The sample stage has machined a group of accurate location pinholes, ensuring the 10 µm2 measurement consistency. As a demonstration, the platinum thin films with different thickness were fabricated by varying ALD cycles. The surface morphology was monitored successively during the deposition. Under vacuum with controlled oxygen partial pressure, the aging and sintering phenomenon of particles has been studied in the AFM testing chamber after high temperature treatment. The integrated AFM/ALD instrument is potentially a powerful system for monitoring the thin film preparation and characterization.

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