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Lutein, a potent antioxidant and the main macular pigment that protects the macula from light-initiated oxidative damage, has low bioavailability. Various nanoscale delivery systems have been developed for improving its bioavailability. This systematic review aims to evaluate the effectiveness of nanoscale delivery systems on improving lutein bioavailability in rodent models. Using EBSCOhost and PubMed, a total of eleven peer-reviewed articles published from 2000 to 2020 were identified. Plasma lutein concentration, pharmacokinetic parameters, including maximum concentration (Cmax), area under curve (AUC), and time to reach the maximum concentration (Tmax), and lutein accumulation in organs were extracted to evaluate the bioavailability of lutein using nanoscale delivery methods as compared with unencapsulated or raw lutein. Various nanoscale delivery systems, including polymer nanoparticles, emulsions, and lutein nanoparticles, significantly improved the bioavailability of lutein, as evidenced by increased plasma lutein concentrations, Cmax, or AUC. Additionally, five out of seven studies observed enhanced accumulation of lutein in the liver and the eyes. Polymer nanoparticles and emulsions improve the dispersibility and stability of lutein, thus lutein might be more accessible in the small intestine. Lutein nanoparticles shortened the Tmax. Further studies are warranted to evaluate the effectiveness of nanoscale delivery systems on improving the functionalities of lutein. [ABSTRACT FROM AUTHOR]

Single atom catalysts (SACs) have displayed unprecedented activity and selectivity toward the electrochemical CO2 reduction reaction (CO2RR). Herein, first-row transition metal embedded pyrazine-based graphynes (TM-pyGYs) were evaluated as potential SACs for the CO2RR by using density functional theory. The computational results showed that TM-pyGYs exhibited large cohesive energies ranging from 6.67 to 6.78 eV per atom and metal binding energies ranging from 0.79 to 5.48 eV. Electronic structure analyses demonstrated the strong covalent bond, large charge transfer, and distinct orbital overlap between the TM atoms and pyGY, which proved the high stability of TM-pyGYs in the CO2RR. Most TM-pyGYs exhibited preferred CO2RR selectivity over the hydrogen evolution reaction. The most favorable reaction pathways of the CO2RR to CO, HCOOH, CH3OH, and CH4 on TM-pyGYs were systematically explored. Among all the TM-pyGYs, Mn/Fe/Ni-pyGYs were determined to be outstanding electrocatalysts in the CO2RR for producing HCOOH with low limiting potentials of −0.21 to −0.36 V, and Co-pyGY exhibited high-performance CO2RR to CH4 with a low limiting potential of −0.35 V, which surpassed the performance of the vast majority of electrocatalysts. With applied potential, Fe/Co/Ni-pyGYs exhibited great advantages in the CO2RR to CH4. The results of this work highlighted TM-pyGYs as ideal SACs for the electrochemical CO2RR. [ABSTRACT FROM AUTHOR]

CO2 capture and separation by using charge‐modulated adsorbent materials is a promising strategy to reduce CO2 emissions. Herein, three TM‐HAB (TM=Co, Ni, and Cu; HAB=hexa‐aminobenzene) metal‐organic frameworks (MOFs) were evaluated as charge‐modulated CO2 capture and separation materials by using density functional theory and grand canonical Monte Carlo simulations. The results showed that each TM‐HAB presented a high electrical conductivity and structural stability when injecting charges. The CO2 adsorption energy increased from 0.211 to 2.091 eV on Co‐HAB, 0.262 to 2.119 eV on Ni‐HAB, and 0.904 to 2.803 eV on Cu‐HAB, respectively, with the increase in charge state from 0.0 to 3.0 e−. Co‐HAB and Ni‐HAB were better charge‐modulated CO2 capture materials with less structure deformation based on energy decomposition analyses. The kinetic process demonstrated that considerably low energy consumptions of 0.911 and 1.589 GJ ton−1 CO2 were observed for a complete adsorption–desorption cycle on Co‐HAB and Ni‐HAB. All charged MOFs, especially Co‐HAB and Ni‐HAB, exhibited higher CO2 adsorption energies and adsorption capacities than those of H2, N2, and CH4, thereby exhibiting high CO2 selectivities. Interaction analysis confirmed that the injecting charges had a more pronounced enhancement in the coulombic interactions between CO2 and MOFs. The results of this work highlight Co‐HAB and Ni‐HAB as promising charge‐modulated CO2 capture and separation materials with controllable CO2 capture, high selectivity, and low energy consumption. [ABSTRACT FROM AUTHOR]

The high specific surface area and electrical conductivity of new 2D metal carbide MXenes make them become a suitable candidate as sensor platform of the gas sensor. Herein, density functional theory (DFT) is implemented to investigate the adsorption of the SF6 decomposed gases (SOF2, SO2, and H2S) on Ti3C2O2, Ti3C2F2, and Ti3C2(OH)2. Modification of the surface of Ti3C2O2 and Ti3C2F2 by O and F point vacancy, respectively, is then performed to improve the adsorption performance. The band structure, charge density differences, electron localization function (ELF), and projected density of states (PDOS) are investigated to study the adsorption mechanism. The results indicate that as compared with the weak adsorption on pristine Ti3C2O2 and Ti3C2F2, the SOF2, SO2, and H2S gas molecules tend to be chemisorbed on Ti3C2O2 and Ti3C2F2 with point vacancy with high adsorption energies. Furthermore, the study of electronic properties suggests that all adsorption systems show high electronic conductivity and the exposed Ti atoms by point defect mainly contribute to the formation of ionic bond with high adsorption energy. Thus, the present results show that Ti3C2O2 and Ti3C2F2 with point vacancy are feasible novel sensing materials to detect SF6 decomposed species with high sensitivity and low electronic noise. The sensitive detection capability of SO2 is particularly noticeable. [ABSTRACT FROM AUTHOR]

As a global public health issue with an increasing prevalence, obesity is related to several metabolic disorders, but is largely preventable. Resistant starch (RS), the indigestible portion of starch, has been studied for its potential effects on reducing obesity. This systematic review aimed to investigate the effect of dietary intake of RS on obesity development and related metabolic profiles in human, including body weight and composition, energy intake and satiety, lipid profiles, blood glucose and insulin, and other blood biomarkers. Eleven peer-reviewed articles published in English between 2000 and 2019 were identified after screening using CENTRAL, MEDLINE, and CINAHL Plus. Based on the results, RS intake had no direct effect on body weight and body composition. Evidence for its effect on reducing energy intake and increasing satiety, as well as improving lipid profiles was inconsistent. Beneficial effects of RS intake on several blood biomarkers were supported, indicating its regulatory roles in blood glucose homeostasis, insulin sensitivity, and gut hormone concentrations. Specifically, five out of the eight articles measuring blood glucose reported a decrease in either fasting or postprandial glucose levels; two out of the three articles measuring insulin sensitivity indicated a significant improvement after RS supplementation; studies measuring gut hormone concentrations including glucagon-like peptide 1 (GLP-1), and peptide YY (PYY) also showed significant improvements after RS interventions. In conclusion, the effect of dietary intake of RS on obesity and its related metabolic complications was not conclusive. Further research with larger sample sizes and longer duration is warranted. [ABSTRACT FROM AUTHOR]