Single Fe atoms dispersed on hierarchically structured porous carbon (SA‐Fe‐HPC) frameworks are prepared by pyrolysis of unsubstituted phthalocyanine/iron phthalocyanine complexes confined within micropores of the p...
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Single Fe atoms dispersed on hierarchically structured porous carbon (SA‐Fe‐HPC) frameworks are prepared by pyrolysis of unsubstituted phthalocyanine/iron phthalocyanine complexes confined within micropores of the porous carbon support. The single‐atom Fe catalysts have a well‐defined atomic dispersion of Fe atoms coordinated by N ligands on the 3D hierarchically porous carbon support. These SA‐Fe‐HPC catalysts are comparable to the commercial Pt/C electrode even in acidic electrolytes for oxygen reduction reaction (ORR) in terms of the ORR activity ( E 1/2 =0.81 V), but have better long‐term electrochemical stability (7 mV negative shift after 3000 potential cycles) and fuel selectivity. In alkaline media, the SA‐Fe‐HPC catalysts outperform the commercial Pt/C electrode in ORR activity ( E 1/2 =0.89 V), fuel selectivity, and long‐term stability (1 mV negative shift after 3000 potential cycles). Thus, these nSA‐Fe‐HPCs are promising non‐platinum‐group metal ORR catalysts for fuel‐cell technologies.
Phycocyanin is one of the pigments found in Spirulina platensis. Phycocyanin has potential as natural blue dye and antioxidant. The application of phycocyanin as food ingredient is still limited due to its vulnerabili...
Phycocyanin is one of the pigments found in Spirulina platensis. Phycocyanin has potential as natural blue dye and antioxidant. The application of phycocyanin as food ingredient is still limited due to its vulnerability to environment. Microencapsulation can keep phycocyanin from environmental influences such as temperature, light and pH. This research aimed to determine the antioxidant activity of phycocyanin microencapsulation with carrageenan and chitosan coating material caused by the effect of thermal degradation overtime and its influence on the physical characteristics of the microencapsulation. The highest antioxidant activity of 61.48% was found in chitosan coating material that occurred at temperature of 40° with 30 minutes heat *** microcapsule with chitosan has more vibrant blue color compared to *** microencapsulation either by using carrageenan or chitosan have functional groups such as alkane, alcohol, ether and ester.
The objective of this study was to evaluate the chemical profile of extracts (aqueous and ethanol) and the essential oil of Myrocarpus frondosus Allem?o, the sensitivity of strains of Escherichia coli, Staphylococcus ...
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The objective of this study was to evaluate the chemical profile of extracts (aqueous and ethanol) and the essential oil of Myrocarpus frondosus Allem?o, the sensitivity of strains of Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Listéria monocytogenes, front the extracts and essential oil, by means of the microdilution method in broth, the antioxidant activity by the ABTS method, and the content of phenolic compounds present in the extracts and oil. For the preparation of extracts from plant leaves used with ethanol and water, then separated, the chemical identification of compounds was performed by high-performance liquid chromatography (CLAE-DAD) and gas chromatography coupled to mass spectrum (CG/MS). With the chemical analysis of the extracts obtained the presence of the major compound rutin, and oil major compound was found germacrene B. In the microdilution method in broth, oil and extracts showed inhibition against all the bacteria tested in the concentrations 1 mg/ml to 0.25 mg/ml, except for Staphylococcus aureus at a concentration of 0.25 mg/ml of the essential oil and trans-caryophyllene. The results of Minimum Bactericidal Concentration showed that the essential oil had bactericidal activity at a concentration of 1mg/ml for all bacteria tested and trans-caryophyllene at the same concentration only for Listeria monocytogenes. In relation to the essential oil, antioxidant activity showed higher radical reduction capacity of 40.92% and the content of phenolic compounds ethanol extract showed more 12.72%. The in vitro results support the conclusion that the essential oil is very promising both in antimicrobial action as antioxidant activity and the leaf extracts on antioxidant activity.
We have designed a series of mechanochromic devices inspired by nature with the capabilities of changing transparency and "switching on/off" luminescence in response to mechanical stimuli. The key to accompl...
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We have designed a series of mechanochromic devices inspired by nature with the capabilities of changing transparency and "switching on/off" luminescence in response to mechanical stimuli. The key to accomplish these excellent optical properties is to control strain-induced surface engineering,that is,the longitudinal cracks opening and transverse invaginated folds. All of these devices are comprised of a rigid thin layer atop polydimethylsiloxane(PDMS) based elastomer,which can be facilely and quickly fabricated. For transparency change mechanochromism,the folds and cracks with excellent light trapping and scattering capabilities can endow high opaqueness to the originally highly transparent samples. The evolution of crack opening and fold–ridge mechanisms are captured through finite analysis that incorporates damage and cracks in the rigid thin layer. For luminescent mechanochromism,the strain-tunable cracks on the UV shield layer act as "gates" to mediate the traveling of UV light to "switch on/off" the luminescence of mechanochromism. This device exhibits a remarkably high strain responsive sensitivity,demonstrating an excellent sensing capability for detecting mechanical failure or damage. All the mechanochromisms also show outstanding durability and reversibility.
Wir stellen die Biokonjugation von Polymeren vor, die durch RAFT‐Polymerisation mittels Hetero‐Diels‐Alder‐Cycloaddition durch ihren inhärenten terminalen Thiocarbonylthiorest mit einem dienmodifizierten Mode...
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Wir stellen die Biokonjugation von Polymeren vor, die durch RAFT‐Polymerisation mittels Hetero‐Diels‐Alder‐Cycloaddition durch ihren inhärenten terminalen Thiocarbonylthiorest mit einem dienmodifizierten Modellprotein synthetisiert wurden und keine spezifische funktionelle Endgruppe tragen. Die quantitative Konjugation erfolgt im Verlauf einiger Stunden bei Raumtemperatur und nahezu neutralem pH‐Wert und in Abwesenheit jeglichen Katalysators. Unsere Technologieplattform liefert thermoresponsive Biokonjugate, deren Aggregation allein durch die Polymerketten gesteuert wird.
Interfaces are ubiquitous in Li-ion battery electrodes, occurring across compositional gradients, regions of multiphase intergrowths, and between electrodes and solid electrolyte interphases or protective coatings. Ho...
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