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1.
J Med Virol ; 96(4): e29611, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38639305

RESUMEN

While micronutrients are crucial for immune function, their impact on humoral responses to inactivated COVID-19 vaccination remains unclear. We investigated the associations between seven key micronutrients and antibody responses in 44 healthy adults with two doses of an inactivated COVID-19 vaccine. Blood samples were collected pre-vaccination and 28 days post-booster. We measured circulating minerals (iron, zinc, copper, and selenium) and vitamins (A, D, and E) concentrations alongside antibody responses and assessed their associations using linear regression analyses. Our analysis revealed inverse associations between blood iron and zinc concentrations and anti-SARS-CoV-2 IgM antibody binding affinity (AUC for iron: ß = -258.21, p < 0.0001; zinc: ß = -17.25, p = 0.0004). Notably, antibody quality presented complex relationships. Blood selenium was positively associated (ß = 18.61, p = 0.0030), while copper/selenium ratio was inversely associated (ß = -1.36, p = 0.0055) with the neutralizing ability against SARS-CoV-2 virus at a 1:10 plasma dilution. There was no significant association between circulating micronutrient concentrations and anti-SARS-CoV-2 IgG binding affinity. These findings suggest that circulating iron, zinc, and selenium concentrations and copper/selenium ratio, may serve as potential biomarkers for both quantity (binding affinity) and quality (neutralization) of humoral responses after inactivated COVID-19 vaccination. Furthermore, they hint at the potential of pre-vaccination dietary interventions, such as selenium supplementation, to improve vaccine efficacy. However, larger, diverse studies are needed to validate these findings. This research advances the understanding of the impact of micronutrients on vaccine response, offering the potential for personalized vaccination strategies.


Asunto(s)
COVID-19 , Selenio , Oligoelementos , Adulto , Humanos , Micronutrientes , Vacunas contra la COVID-19 , Cobre , COVID-19/prevención & control , SARS-CoV-2 , Zinc , Hierro , Vacunación , Anticuerpos Antivirales , Anticuerpos Neutralizantes
2.
Materials (Basel) ; 17(8)2024 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-38673275

RESUMEN

Ecological porous concrete (EPC) is one of the novel formulations of concrete with unique phytogenic properties. However, achieving both low alkalinity and high strength in EPC proves challenging due to the inherently high alkalinity of the pore environment, which hinders the growth of the plant and affects its ecological benefits significantly. This research investigated the utilization of 15 types of chemical admixtures and diatomaceous earth as alkali-reducing agents to optimize the properties of silicate cementitious materials for the applications of EPC. To identify the most effective agents, the pH value and compressive strength of the cement paste were adopted as the screening criteria for the selection of the essential alkali-reducing ingredients. Subsequently, a composite approach combining chemical admixtures and DE was employed to explore the synergistic effects on the pH and strength of silicate cementitious materials. The results revealed that a combination of 8% DE, 5% oxalic acid, and 5% iron sulfate functioned effectively and resulted in desirable performance for the concrete. This synergistic blend effectively consumed a large amount of Ca(OH)2, reducing the pH of cement paste to 10.48 within 3 days. Furthermore, the hydration reaction generated C-S-H with a low Ca/Si ratio, leading to a remarkable increase in the compressive strength of the concrete, reaching 89.7 MPa after 56 days. This composite approach ensured both low alkalinity and high strength in silicate cementitious materials, providing a theoretical basis for the application and promotion of EPC in the ecological field.

3.
Biomedicines ; 12(1)2024 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-38255301

RESUMEN

NKG2D is an activating receptor expressed by all human NK cells and CD8 T cells. Harnessing the NKG2D/NKG2D ligand axis has emerged as a viable avenue for cancer immunotherapy. However, there is a long-standing controversy over whether soluble NKG2D ligands are immunosuppressive or immunostimulatory, originating from conflicting data generated from different scopes of pre-clinical investigations. Using multiple pre-clinical tumor models, we demonstrated that the impact of the most characterized human solid tumor-associated soluble NKG2D ligand, the soluble MHC I chain-related molecule (sMIC), on tumorigenesis depended on the tumor model being studied and whether the tumor cells possessed stemness-like properties. We demonstrated that the potential of tumor formation or establishment depended upon tumor cell stem-like properties irrespective of tumor cells secreting the soluble NKG2D ligand sMIC. Specifically, tumor formation was delayed or failed if sMIC-expressing tumor cells expressed low stem-cell markers; tumor formation was rapid if sMIC-expressing tumor cells expressed high stem-like cell markers. However, once tumors were formed, overexpression of sMIC unequivocally suppressed tumoral NK and CD8 T cell immunity and facilitated tumor growth. Our study distinguished the differential impacts of soluble NKG2D ligands in tumor formation and tumor progression, cleared the outstanding controversy over soluble NKG2D ligands in modulating tumor immunity, and re-enforced the viability of targeting soluble NKG2D ligands for cancer immunotherapy for established tumors.

4.
Vaccine ; 41(52): 7641-7646, 2023 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-38016845

RESUMEN

A third dose of inactivated virus vaccine (IVV) boosts neutralizing antibodies, reducing SARS-CoV-2 transmission rate and COVID-19 severity. However, the impact of RBD-elicited antibodies and their neutralizing activity by the boost of IVV is unknown. We investigated the impact of IVV's boost shot on RBD-elicited antibodies and their neutralizing activity in 18 subjects receiving the second and third IVV doses. Using an RBD antibodies depletion assay, we assessed the neutralizing activity of RBD-elicited antibodies. After the second dose, RBD-antigen elicitation accounted for ∼60% of neutralizing activity, which increased to 82% after the IVV boost against ancestral SARS-CoV-2. Depleting class 3 and class 4-specific antibodies with the Beta-RBD protein revealed that NAbs targeting RBD class 1 and class 2 subdomains increased from 57% to 75% post-boost. These findings highlight the significant enhancement of RBD-specific antibodies, especially against RBD class 1 and class 2, with IVV booster doses. Our study offers valuable insights for optimizing COVID-19 vaccine strategies.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , Epítopos , Vacunas de Productos Inactivados , Vacunas contra la COVID-19 , COVID-19/prevención & control , Anticuerpos , Anticuerpos Bloqueadores , Anticuerpos Neutralizantes , Anticuerpos Antivirales
5.
J Hepatocell Carcinoma ; 10: 893-908, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37313302

RESUMEN

Recurrence of hepatocellular carcinoma (HCC) negatively affects the quality of life of patients and leads to death. Studies have shown that recurrent hepatocellular carcinoma (RHCC) is closely related to tissue hypoxia and autophagy. It has been shown that hypoxia-inducible factor-1α (HIF-1α) and its downstream factor BCL-2 19 kDa-interacting protein 3 (BNIP3) promote cellular autophagy under hypoxic conditions, resulting in metastasis and RHCC. In this article, the molecular structures of HIF-1α and BNIP3 are described, and the significance of the HIF-1α/BNIP3 signaling pathway in RHCC is explained. Moreover, the role and mechanism of traditional Chinese medicine (TCM) in treating RHCC by modulating the HIF-1α/BNIP3 signaling pathway is discussed. Studies have shown that the HIF-1α/BNIP3 signaling pathway is a potential target of TCM in the treatment of RHCC. The mechanism of the HIF-1α/BNIP3 signaling pathway in RHCC and the progress achieved in TCM research on targeting and regulating this pathway are also reviewed in this article. The objective was to provide a theoretical basis for the prevention and treatment of RHCC, as well as further drug development.

6.
Medicine (Baltimore) ; 102(2): e32625, 2023 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-36637946

RESUMEN

BACKGROUND: The mortality rate and prognosis of patients with hepatocellular carcinoma (HCC) are well known. A variety of highly malignant human cancers express mitotic arrest deficient 2 like 1 (MAD2L1), a transcription factor that plays a critical role in their development and progression. However, MAD2L1's particular mechanisms and effects on HCC remain uncertain. METHODS: We performed a pan-cancer analysis for MAD2L1 prognosis and expression using The Cancer Genome Atlas and Genotype-Tissue Expression data in the present study. MAD2L1 may act as an oncogene in HCC, and a combination of in silico analyses, including expression, survival, and correlation analyses, were performed to identify non-coding ribonucleic acids (ncRNAs) that contribute to MAD2L1 overexpression. RESULTS: In conclusion, MAD2L1 is most likely regulated by HCP5/miRNA-139-5p/MAD2L1 in HCC based on its upstream ncRNA-related pathway. A significant positive association was also found between MAD2L1 levels and tumor immune cell infiltration, immune cell biomarkers, and immune checkpoint expression. CONCLUSION: Our findings demonstrate that ncRNA-mediated upregulation of MAD2L1 in HCC is closely related to poor prognosis and tumor infiltration.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroARNs , Humanos , Carcinoma Hepatocelular/genética , Regulación hacia Arriba , Neoplasias Hepáticas/genética , Activación Transcripcional , Oncogenes , ARN no Traducido , Pronóstico , Biomarcadores de Tumor , Proteínas Mad2/genética
7.
J Appl Gerontol ; 42(1): 111-120, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36204775

RESUMEN

This study aims to examine the association between intergenerational support and self-rated health (SRH) levels using data collected from Chinese older adults residing in Honolulu, United States (N = 329). We also investigated the mediating role of resilience and the moderating role of gender in the association. We found that receiving emotional support was significantly and positively associated with better SRH for the whole sample. The positive effect of receiving emotional support on health was significant among older women only. In contrast, the beneficial effect of providing economic support on health was significant among older men only. We found that resilience significantly mediated the positive effect of received emotional support on SRH, and this effect was found for the whole sample and among older women. However, resilience did not mediate the positive effect of the economic support provided on SRH among older men.


Asunto(s)
Pueblos del Este de Asia , Estado de Salud , Masculino , Humanos , Femenino , Anciano , Pueblo Asiatico
8.
Curr Opin Chem Biol ; 70: 102188, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35970133

RESUMEN

Natural materials possess many distinctive "living" attributes, such as self-growth, self-healing, environmental responsiveness, and evolvability, that are beyond the reach of many existing synthetic materials. The emerging field of engineered living materials (ELMs) takes inspiration from nature and harnesses engineered living systems to produce dynamic and responsive materials with genetically programmable functionalities. Here, we identify and review two main directions for the rational design of ELMs: first, engineering of living materials with enhanced performances by incorporating functional material modules, including engineered biological building blocks (proteins, polysaccharides, and nucleic acids) or well-defined artificial materials; second, engineering of smart ELMs that can sense and respond to their surroundings by programming dynamic cellular behaviors regulated via cell-cell or cell-environment interactions. We next discuss the strengths and challenges of current ELMs and conclude by providing a perspective of future directions in this promising area.


Asunto(s)
Ácidos Nucleicos , Proteínas , Proteínas/genética
9.
Nanoscale ; 14(26): 9466-9473, 2022 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-35748335

RESUMEN

The density derived electrostatic and chemical (DDEC) approach for calculating the charges of atoms in a metal-organic framework (MOF) is considered to be the most accurate (yet computationally costly) one among many charge-assignment methods. Here, we conducted a comparative study on five different types of atomic partial charges (namely CM5, Mulliken, Qeq, EQeq and PACMOF) prepared for a subset of MOFs with affordable computational costs and benchmarked them with respect to the DDEC charges, which is particularly relevant because currently most databases lack MOFs with pre-calculated DDEC charges. To find a suitable charge type alternative to the DDEC approach, we statistically ranked the five charge types based on two metrics, the relative standard deviation of charges and relative dipole moment difference, based on which we provide general guidance as well as suggestions for specific MOFs according to bond polarity analyses. Finally, we recommend a possible and more accurate parametrization scheme for future studies.

10.
Psychol Rep ; 125(3): 1438-1456, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33757372

RESUMEN

There is evidence that greater aesthetic experience can be linked to artworks when their corresponding meanings can be successfully inferred and understood. Modern cultural-expo architecture can be considered a form of artistic creation and design, and the corresponding design philosophy may be derived from representational objects or abstract social meanings. The present study investigates whether cultural-expo architecture with an easy-to-understand architectural appearance design is perceived as more beautiful and how architectural photographs and different types of descriptions of architectural appearance designs interact and produce higher aesthetic evaluations. The results showed an obvious aesthetic preference for cultural-expo architecture with an easy-to-understand architectural appearance design (Experiment 1). Moreover, we found that the aesthetic rating score of architectural photographs accompanied by an abstract description was significantly higher than that of those accompanied by a representational description only under the difficult-to-understand design condition (Experiment 2). The results indicated that people preferred cultural-expo architecture with an easy-to-understand architectural appearance design due to a greater understanding of the design, providing further evidence that abstract descriptions can provide supplementary information and explanation to enhance the sense of beauty of abstract cultural-expo architecture.


Asunto(s)
Belleza , Semántica , Estética , Humanos , Filosofía
11.
Biomimetics (Basel) ; 6(2)2021 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-34067202

RESUMEN

Whether the lower limb prosthesis can better meet the needs of amputees, the biomimetic performance of the knee joint is particularly important. In this paper, Nokov(metric) optical 3D motion capture system was used to collect motion data of normal human lower limbs, and the motion instantaneous center of multi-gait knee joint was obtained. Taking the error of knee joint motion instantaneous center line as the objective function, a set of six-bar mechanism prosthetic knee joint was designed based on a genetic algorithm. The experimental results show that the movement trajectory of the instantaneous center of the knee joint is basically similar to that of the human knee joint, so it can help amputees complete a variety of gaits and has good biomimetic performance. Gait acquisition technology can provide important data for prosthetic designers and it will be widely used in prosthetic design and other fields.

12.
Sci Technol Adv Mater ; 21(1): 817-832, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33628120

RESUMEN

Elastomers such as gels and rubbers play various roles in our lives. Elastomers, which guarantee the safety of airplanes and automobiles and the stability of buildings, are materials that have made the lives of people in the twentieth century extremely convenient. The existence of macromolecules, that is, giant molecules, has been clarified; the development of synthetic macromolecules has progressed; and understanding of elastomers has progressed. By introducing new ideas, it has become possible to obtain tough and hard elastomers, which was difficult under conventional ideas. In this paper, we will explain the development from the classical theory of elastomers to current efforts.

13.
J Hematol Oncol ; 14(1): 7, 2021 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-33407739

RESUMEN

Natural killer (NK) cell is a specialized immune effector cell type that plays a critical role in immune activation against abnormal cells. Different from events required for T cell activation, NK cell activation is governed by the interaction of NK receptors with target cells, independent of antigen processing and presentation. Due to relatively unsophisticated cues for activation, NK cell has gained significant attention in the field of cancer immunotherapy. Many efforts are emerging for developing and engineering NK cell-based cancer immunotherapy. In this review, we provide our current understandings of NK cell biology, ongoing pre-clinical and clinical development of NK cell-based therapies and discuss the progress, challenges, and future perspectives.


Asunto(s)
Inmunoterapia Adoptiva/métodos , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/trasplante , Neoplasias/terapia , Animales , Ensayos Clínicos como Asunto , Humanos , Vigilancia Inmunológica , Células Asesinas Naturales/citología , Activación de Linfocitos , Neoplasias/inmunología , Escape del Tumor
14.
Molecules ; 25(8)2020 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-32340399

RESUMEN

Lithium-sulfur batteries are very promising next-generation energy storage batteries due to their high theoretical specific capacity. However, the shuttle effect of lithium-sulfur batteries is one of the important bottlenecks that limits its rapid development. Herein, physical and chemical dual adsorption of lithium polysulfides are achieved by designing a novel framework structure consisting of MnO2, reduced graphene oxide (rGO), and carbon nanotubes (CNTs). The framework-structure composite of MnO2/rGO/CNTs is prepared by a simple hydrothermal method. The framework exhibits a uniform and abundant mesoporous structure (concentrating in ~12 nm). MnO2 is an α phase structure and the α-MnO2 also has a significant effect on the adsorption of lithium polysulfides. The rGO and CNTs provide a good physical adsorption interaction and good electronic conductivity for the dissolved polysulfides. As a result, the MnO2/rGO/CNTs/S cathode delivered a high initial capacity of 1201 mAh g-1 at 0.2 C. The average capacities were 916 mAh g-1, 736 mAh g-1, and 547 mAh g-1 at the current densities of 0.5 C, 1 C, and 2 C, respectively. In addition, when tested at 0.5 C, the MnO2/rGO/CNTs/S exhibited a high initial capacity of 1010 mAh g-1 and achieved 780 mAh g-1 after 200 cycles, with a low capacity decay rate of 0.11% per cycle. This framework-structure composite provides a simple way to improve the electrochemical performance of Li-S batteries.


Asunto(s)
Suministros de Energía Eléctrica , Grafito/química , Litio/química , Compuestos de Manganeso/química , Estructuras Metalorgánicas/química , Nanotubos de Carbono/química , Azufre/química , Electroquímica , Electrodos , Estructuras Metalorgánicas/ultraestructura , Análisis Espectral
15.
Arch Gerontol Geriatr ; 88: 104015, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32007644

RESUMEN

A growing body of literature found that anxiety about aging is related to health and well-being of older adults. However, very few studies have been conducted on Chinese older adults residing in different countries and examined the role of resilience. Using the Pearlin's Stress Process Model, this study aims to fill in this gap by examining the relationship between anxiety about aging as the stressor and health status among Chinese older adults living in Honolulu, the United States (N = 292) and Wuhan, China (N = 532). The survey data were collected through June 2017 to September 2018, using snowball and convenience sampling strategy. The moderating role of resilience on the focal relationship is also explored. Results showed that for both samples, the negative relationship between anxiety about aging and self-rated health was significantly moderated by resilience (18 % and 13 %, respectively), implying the stress-buffering role of resilience. Although both mean levels of resilience and anxiety about aging were lower for the Honolulu sample, the moderating effect appeared to be stronger, implying that older adults in the Honolulu sample might rely more on psychological resources such as resilience in coping with stressors, compared with their counterparts in Wuhan. However, the moderating effect of resilience did not work for the association between anxiety about aging and number of chronic conditions for both samples. Our findings suggest that future research needs to take into account both social and psychological resources when examining anxiety about aging and health status among Chinese older adults residing in different cultural contexts.


Asunto(s)
Ansiedad , Estado de Salud , Resiliencia Psicológica , Anciano , Envejecimiento , Ansiedad/epidemiología , China/epidemiología , Hawaii/epidemiología , Humanos
16.
Environ Pollut ; 259: 113707, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31887600

RESUMEN

In recent days, garbage classification has become a hot topic in China, and Shanghai took the lead in the implementation of garbage classification legislation in China. Starting from the current situation of garbage classification in China, this study emphasizes the garbage classification in terms of law, amount, economy, management, resourcing and successful experience of garbage classification in China, so as to provide inspiration and guidance for garbage classification for other countries.


Asunto(s)
Residuos de Alimentos , Eliminación de Residuos , China , Humanos
17.
Gerontologist ; 60(2): 229-238, 2020 02 24.
Artículo en Inglés | MEDLINE | ID: mdl-31322675

RESUMEN

BACKGROUND AND OBJECTIVES: A growing body of literature indicates that neighborhood social cohesion is generally associated with lower levels of psychological distress and higher levels of life satisfaction (LS). However, very few studies have examined these relationships among Chinese older adults, the fastest growing aging population across all racial/ethnic groups in the U.S. Focusing on this population, the current study aims to examine the associations of neighborhood cohesion with psychological distress and LS as well as the mediating role of resilience and the moderating role of birth place in the associations. RESEARCH DESIGN AND METHODS: Ordinary least squares regressions were applied to analyze data collected among 430 Chinese older adults aged 55 and older residing in Honolulu, Hawai'i. RESULTS: Results show that neighborhood social cohesion was positively associated with lower levels of psychological distress and higher levels of LS for the whole sample. The association between social cohesion and psychological distress was moderated by birth place such that the protecting effects of neighborhood cohesion on distress were only salient for the U.S.-born but not for the foreign-born. Moreover, the mediating role of resilience was identified: It contributed to more than 60% of the association between social cohesion and psychological distress, and more than 22% of the association between social cohesion and LS. DISCUSSION AND IMPLICATIONS: Our findings indicate the importance of a cohesive social environment and resilience in shaping psychological well-being and quality of life for older Chinese adults, the U.S.-born in particular, living in Honolulu, Hawai'i.


Asunto(s)
Asiático/estadística & datos numéricos , Satisfacción Personal , Distrés Psicológico , Resiliencia Psicológica , Anciano , Anciano de 80 o más Años , Asiático/psicología , Estudios Transversales , Emigrantes e Inmigrantes/psicología , Emigrantes e Inmigrantes/estadística & datos numéricos , Femenino , Hawaii/etnología , Humanos , Masculino , Persona de Mediana Edad , Características de la Residencia , Medio Social , Encuestas y Cuestionarios
18.
J Clin Med ; 8(9)2019 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-31546818

RESUMEN

Natural killer (NK) cells are critical immune components in controlling tumor growth and dissemination. Given their innate capacity to eliminate tumor cells without prior sensitization, NK-based therapies for cancer are actively pursued pre-clinically and clinically. However, recent data suggest that tumors could induce functional alterations in NK cells, polarizing them to tumor-promoting phenotypes. The potential functional plasticity of NK cells in the context of tumors could lead to undesirable outcomes of NK-cell based therapies. In this review, we will summarize to-date evidence of tumor-associated NK cell plasticity and provide our insights for future investigations and therapy development.

19.
Langmuir ; 35(40): 13189-13195, 2019 10 08.
Artículo en Inglés | MEDLINE | ID: mdl-31547644

RESUMEN

In clinics it is extremely important for implanted devices to achieve the property of enhanced lubrication and bacterial resistance; however, such a strategy has rarely been reported in previous literature. In the present study, a surface functionalization method, motivated by articular cartilage-inspired superlubrication and mussel-inspired adhesion, was proposed to modify titanium alloy (Ti6Al4V) using the copolymer (DMA-MPC) synthesized via free radical copolymerization. The copolymer-coated Ti6Al4V (Ti6Al4V@DMA-MPC) was evaluated by X-ray photoelectron spectroscopy, water contact angle, and Raman spectra to confirm that the DMA-MPC copolymer was successfully coated onto the Ti6Al4V substrate. In addition, the tribological test, with the polystyrene microsphere and Ti6Al4V or Ti6Al4V@DMA-MPC as the tribopair, indicated that the friction coefficient was greatly reduced for Ti6Al4V@DMA-MPC. Furthermore, the bacterial resistance test showed that bacterial attachment was significantly inhibited for Ti6Al4V@DMA-MPC for the three types of bacteria tested. The enhanced lubrication and bacterial resistance of Ti6Al4V@DMA-MPC was due to the tenacious hydration shell formed surrounding the zwitterionic charges in the phosphorylcholine group of the DMA-MPC copolymer. In summary, a bioinspired surface functionalization strategy is developed in this study, which can act as a universal and promising method to achieve enhanced lubrication and bacterial resistance for biomedical implants.


Asunto(s)
Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Materiales Biocompatibles Revestidos/química , Lubricantes/farmacología , Metacrilatos/farmacología , Fosforilcolina/análogos & derivados , Titanio/química , Aleaciones , Animales , Antibacterianos/química , Antibacterianos/toxicidad , Línea Celular , Materiales Biocompatibles Revestidos/toxicidad , Escherichia coli/efectos de los fármacos , Escherichia coli/fisiología , Lubricantes/química , Lubricantes/toxicidad , Lubrificación , Metacrilatos/química , Metacrilatos/toxicidad , Ratones , Fosforilcolina/química , Fosforilcolina/farmacología , Fosforilcolina/toxicidad , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/fisiología , Streptococcus mutans/efectos de los fármacos , Streptococcus mutans/fisiología , Titanio/toxicidad
20.
Phys Chem Chem Phys ; 21(36): 20177-20188, 2019 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-31486461

RESUMEN

Prussian blue analogues (PBAs) are promising cation intercalation materials for electrochemical desalination and energy storage applications. Here, we investigate the mechanism of capacity fade and degradation of nickel hexacyanoferrate (NiHCFe) during galvanostatic cycling in aqueous electrolytes that are rich in either Mg2+ or Ca2+. We combine experimental characterization, first principles electronic structure calculations, statistical mechanics and lattice-percolation modeling of electron transfer to elucidate the mechanisms responsible for the degradation of NiHCFe and its partial retention of capacity. Electrochemical characterization of porous NiHCFe electrodes suggests a two-site intercalation mechanism, while spectroscopy reveals the presence of Ni2+ and Fe(CN)63- ions in the electrolyte post cycling in Mg2+(aq). Using simple coprecipitation reactions, we show that Mg2+ and Ni2+ can coexist in the lattice framework, forming stable PBAs. Galvanostatic cycling of these PBAs shows that the presence of Mg2+ in the lattice framework results in the dissolution of Mg1.5FeIII(CN)6 in water during oxidation. We propose that Mg2+ can partially substitute Ni2+ ions in the lattice framework during galvanostatic cycling, displacing the substituted Ni2+ ions into interstitial sites. Based on differential capacitance analysis we show that Mg2+ intercalates into interstitial sites at ∼0.45 V vs. Ag/AgCl and it displaces Ni2+ in the lattice framework at ∼0.05 V vs. Ag/AgCl. Substitution of Ni2+ leads to Fe(CN)63- and Ni2+ ions being removed into the electrolyte during oxidation. Using first principles density functional theory (DFT) calculations combined with a statistical mechanics model, we verify the thermodynamic feasibility of the proposed reaction mechanism and predict the fraction of Ni2+ ions being substituted by Mg2+ during intercalation. Further, analysis of the electron density distribution and local density of states indicates that Mg2+ ions can act as insulating defects in the lattice framework that render certain Fe ions electrically inactive and likely contribute to capacity fade along with dissolution of Fe(CN)63-.

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