Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 49
Filtrar
1.
Int Immunopharmacol ; 138: 112553, 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-38943975

RESUMO

BACKGROUND AND AIMS: Lung adenocarcinoma (LUAD) is the most common and aggressive cancer with a high incidence. N1-specific pseudouridine methyltransferase (EMG1), a highly conserved nucleolus protein, plays an important role in the biological development of ribosomes. However, the role of EMG1 in the progression of LUAD is still unclear. METHODS: The expression of EMG1 in LUAD cells, and LUAD tissues, and adjacent noncancerous tissues was quantified using real-time polymerase chain reaction (PCR) and western blotting. The roles of EMG1 in LUAD cell proliferation, migration, invasion and tumorigenicity were explored in vitro and in vivo. Western blot analysis to underlying molecular mechanism of EMG1 regulating the biological function of LUAD. EMG1 expression and its impact on tumor prognosis were analyzed using a range of databases including GEPIA, UALCAN, cBioPortal, LinkedOmics, and Kaplan-Meier Plotter. RESULTS: EMG1 expression was elevated in LUAD patients compared to normal tissues, and EMG1 expression was strongly correlated with prognosis in LUAD patients. EMG1 expression correlated with age, gender, N stage, T stage, and pathologic stage. EMG1 expression was strongly positively correlated with MRPL51, PHB2, SNRPG, ATP5MD, and TPI1, and strongly negatively correlated with MACF1, DOCK9, RAPGEF2, SYNJ1, and KIDINS220, the major enrichment pathways for EMG1 and related genes include Cell cycle, DNA Replication and Pathways in cancer signaling pathways. EMG1 expression level was significantly increased in LUAD cell lines and tissues. Knockdown of EMG1 could inhibit LUAD cell proliferation, migration, invasion, and tumorigenicity. Besides, EMG1 overexpression could promote LUAD cell proliferation, migration, and invasion. High expression of EMG1 predicts poor prognosis in LUAD patients, and EMG1 may play an oncogenic role in the tumor microenvironment by participating in the infiltration of LUAD immune cells. CONCLUSIONS: EMG1 regulated various functions in LUAD by directly mediating Akt/mTOR/p70s6k signaling pathways activation. The results suggest that EMG1 may be a novel biomarker for assessing prognosis and immune cell infiltration in LUAD.


Assuntos
Adenocarcinoma de Pulmão , Proliferação de Células , Progressão da Doença , Neoplasias Pulmonares , Animais , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Adenocarcinoma de Pulmão/imunologia , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/patologia , Adenocarcinoma de Pulmão/mortalidade , Adenocarcinoma de Pulmão/metabolismo , Biomarcadores Tumorais/metabolismo , Biomarcadores Tumorais/genética , Linhagem Celular Tumoral , Movimento Celular , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Metiltransferases/metabolismo , Metiltransferases/genética , Camundongos Endogâmicos BALB C , Camundongos Nus , Prognóstico
2.
RSC Adv ; 14(17): 12096-12106, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38628486

RESUMO

Prussian blue analogues possess numerous advantages as cathode materials for sodium-ion batteries, including high energy density, low cost, sustainability, and straightforward synthesis processes, making them highly promising for practical applications. However, during the synthesis, crystal defects such as vacancies and the incorporation of crystal water can lead to issues such as diminished capacity and suboptimal cycling stability. In the current study, a Y-tube assisted coprecipitation method was used to synthesize iron-based Prussian blue analogues, and the optimized feed flow rate during synthesis contributed to the successful preparation of the material with a formula of Na1.56Fe[Fe(CN)6]0.90□0.10·2.42H2O, representing a low-defect cathode material. This approach cleverly utilizes the Y-tube component to enhance the micro-mixing of materials in the co-precipitation reaction, featuring simplicity, low cost, user-friendly, and the ability to be used in continuous production. Electrochemical performance tests show that the sample retains 69.8% of its capacity after 200 cycles at a current density of 0.5C (1C = 140 mA g-1) and delivers a capacity of 71.9 mA h g-1 at a high rate of 10C. The findings of this research provide important insights for the development of high-performance Prussian blue analogues cathode materials for sodium-ion batteries.

3.
Cardiovasc Diabetol ; 22(1): 230, 2023 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-37649025

RESUMO

BACKGROUND: The triglyceride-glucose (TyG) index has been evaluated as a reliable surrogate for insulin resistance (IR) and has been proven to be a predictor of poor outcomes in patients with cardiovascular diseases. However, data are lacking on the relationship of the TyG index with prognosis in nondiabetic patients who underwent coronary artery bypass grafting (CABG). Thus, the purpose of our current study was to investigate the potential value of the TyG index as a prognostic indicator in patients without diabetes mellitus (DM) after CABG. METHODS: This multicenter, retrospective cohort study involving 830 nondiabetic patients after CABG from 3 tertiary public hospitals from 2014 to 2018. Kaplan-Meier survival curve analysis was conducted followed by the log-rank test. Cox proportional hazards regression models were used to explore the association between the TyG index and major adverse cardiovascular events (MACEs). The incremental predictive power of the TyG index was evaluated with C-statistics, continuous net reclassification improvement (NRI) and integrated discrimination improvement (IDI). RESULTS: An incrementally higher TyG index was associated with an increasingly higher cumulative incidence of MACEs (log-rank test, p < 0.001). The hazard ratio (95% CI) of MACEs was 2.22 (1.46-3.38) in tertile 3 of the TyG index and 1.38 (1.18-1.62) per SD increase in the TyG index. The addition of the TyG index yielded a significant improvement in the global performance of the baseline model [C-statistic increased from 0.656 to 0.680, p < 0.001; continuous NRI (95% CI) 0.269 (0.100-0.438), p = 0.002; IDI (95% CI) 0.014 (0.003-0.025), p = 0.014]. CONCLUSIONS: The TyG index may be an independent factor for predicting adverse cardiovascular events in nondiabetic patients after CABG.


Assuntos
Doenças Cardiovasculares , Diabetes Mellitus , Humanos , Estudos Retrospectivos , Ponte de Artéria Coronária/efeitos adversos , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologia , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/etiologia , Glucose , Triglicerídeos
4.
Diabetes Metab Res Rev ; 39(8): e3710, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37537868

RESUMO

AIMS: We aimed to investigate the independent and combined association of the triglyceride-glucose (TyG) index and EuroSCORE II with major adverse cardiovascular event (MACE) after coronary artery bypass grafting (CABG), and examine whether the addition of the TyG index improves the predictive performance of the EuroSCORE II. MATERIALS AND METHODS: This study included 1013 patients who underwent CABG. The primary endpoint was MACE, which was defined as the composite of all-cause death, repeat coronary artery revascularisation, non-fatal myocardial infarction and non-fatal stroke. The patients were grouped by the TyG index and EuroSCORE II tertiles and the combination of these risk indicators. RESULTS: During the follow-up, 211 individuals developed MACE. Elevated levels of the TyG index and EuroSCORE II were associated with an increased risk of MACE. The hazard ratio [95% confidence interval (CI)] was 3.66 (2.34-5.73) in patients with the highest tertile of the TyG index and EuroSCORE II. Compared with the EuroSCORE II alone, combining the TyG index with EuroSCORE II achieved a better predictive performance [C-statistic increased 0.032, p < 0.001; continuous net reclassification improvement (NRI) (95% CI): 0.364 (0.215-0.514), p < 0.001; integrated discrimination improvement (IDI) (95% CI): 0.015 (0.007-0.023), p < 0.001, Akaike's information criteria (AIC) and Bayesian information criterion (BIC) decreased, and the likelihood ratio test, p < 0.001]. CONCLUSIONS: The TyG index and EuroSCORE II are independently associated with poor prognosis. Furthermore, the TyG index is an important adjunct to the EuroSCORE II for improving risk stratification and guiding early intervention among post-CABG patients.


Assuntos
Ponte de Artéria Coronária , Glucose , Humanos , Triglicerídeos , Teorema de Bayes , Medição de Risco , Ponte de Artéria Coronária/efeitos adversos , Fatores de Risco , Glicemia , Biomarcadores , Estudos Retrospectivos
5.
Diabetol Metab Syndr ; 15(1): 157, 2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37461067

RESUMO

BACKGROUND: The metabolic score for insulin resistance (METS-IR) is a simple, convenient, and reliable marker for resistance insulin (IR), which has been regarded as a predictor of cardiovascular disease (CVD) and cardiovascular events. However, few studies examined the relationship between METS-IR and prognosis after coronary artery bypass graft (CABG). This study aimed to investigate the potential value of METS-IR as a prognostic indicator for the major adverse cardiovascular events (MACE) in patients after CABG. METHOD: 1100 CABG patients were enrolled in the study, including 760 men (69.1%) and 340 women (30.9%). The METS-IR was calculated as Ln [(2 × FPG (mg/dL) + fasting TG (mg/dL)] × BMI (kg/m2)/Ln [HDL-C (mg/dL)]. The primary endpoint of this study was the occurrence of major adverse cardiovascular events (MACE), including a composite of all-cause death, non-fatal myocardial infarction (MI), coronary artery revascularization, and stroke. RESULT: The following-up time of this study was 49-101 months (median, 70 months; interquartile range, 62-78 months). During the follow-up period, there were 243 MACEs (22.1%). The probability of cumulative incidence of MACE increased incrementally across the quartiles of METS-IR (log-rank test, p < 0.001). Multivariate Cox regression analysis demonstrated a hazard ratio (95% CI) of 1.97 (1.36-2.86) for MACE in quartile 4 compared with participants in quartile 1. The addition of the METS-IR to the model with fully adjusting variables significantly improved its predictive value [C-statistic increased from 0.702 to 0.720, p < 0.001, continuous net reclassification improvement (NRI) = 0.305, < 0.001, integrated discrimination improvement (IDI) = 0.021, p < 0.001]. CONCLUSION: METS-IR is an independent and favorable risk factor for predicting the occurrence of MACE and can be used as a simple and reliable indicator that can be used for risk stratification and early intervention in patients after CABG.

6.
J Cell Biol ; 222(8)2023 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-37382627

RESUMO

A balance between self-renewal and differentiation is critical for the regenerative capacity of tissue-resident stem cells. In skeletal muscle, successful regeneration requires the orchestrated activation, proliferation, and differentiation of muscle satellite cells (MuSCs) that are normally quiescent. A subset of MuSCs undergoes self-renewal to replenish the stem cell pool, but the features that identify and define self-renewing MuSCs remain to be elucidated. Here, through single-cell chromatin accessibility analysis, we reveal the self-renewal versus differentiation trajectories of MuSCs over the course of regeneration in vivo. We identify Betaglycan as a unique marker of self-renewing MuSCs that can be purified and efficiently contributes to regeneration after transplantation. We also show that SMAD4 and downstream genes are genetically required for self-renewal in vivo by restricting differentiation. Our study unveils the identity and mechanisms of self-renewing MuSCs, while providing a key resource for comprehensive analysis of muscle regeneration.


Assuntos
Cromatina , Músculo Esquelético , Regeneração , Células Satélites de Músculo Esquelético , Diferenciação Celular , Divisão Celular , Cromatina/genética
7.
Cardiovasc Diabetol ; 22(1): 103, 2023 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-37131230

RESUMO

BACKGROUND: Elevated serum uric acid (SUA) is regarded as a risk factor for the development of cardiovascular diseases. Triglyceride-glucose (TyG) index, a novel surrogate for insulin resistance (IR), has been proven to be an independent predictor for adverse cardiac events. However, no study has specifically focused on the interaction between the two metabolic risk factors. Whether combining the TyG index and SUA could achieve more accurate prognostic prediction in patients undergoing coronary artery bypass grafting (CABG) remains unknown. METHODS: This was a multicenter, retrospective cohort study. A total of 1225 patients who underwent CABG were included in the final analysis. The patients were grouped based on the cut-off value of the TyG index and the sex-specific criteria of hyperuricemia (HUA). Cox regression analysis was conducted. The interaction between the TyG index and SUA was estimated using relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (SI). The improvement of model performance yielded by the inclusion of the TyG index and SUA was examined by C-statistics, net reclassification improvement (NRI) and integrated discrimination improvement (IDI). The goodness-of-fit of models was evaluated using the Akaike information criterion (AIC), Bayesian information criterion (BIC) and χ2 likelihood ratio test. RESULTS: During follow-up, 263 patients developed major adverse cardiovascular events (MACE). The independent and joint associations of the TyG index and SUA with adverse events were significant. Patients with higher TyG index and HUA were at higher risk of MACE (Kaplan-Meier analysis: log-rank P < 0.001; Cox regression: HR = 4.10; 95% CI 2.80-6.00, P < 0.001). A significant synergistic interaction was found between the TyG index and SUA [RERI (95% CI): 1.83 (0.32-3.34), P = 0.017; AP (95% CI): 0.41 (0.17-0.66), P = 0.001; SI (95% CI): 2.13 (1.13-4.00), P = 0.019]. The addition of the TyG index and SUA yielded a significant improvement in prognostic prediction and model fit [change in C-statistic: 0.038, P < 0.001; continuous NRI (95% CI): 0.336 (0.201-0.471), P < 0.001; IDI (95% CI): 0.031 (0.019-0.044), P < 0.001; AIC: 3534.29; BIC: 3616.45; likelihood ratio test: P < 0.001). CONCLUSIONS: The TyG index interacts synergistically with SUA to increase the risk of MACE in patients undergoing CABG, which emphasizes the need to use both measures concurrently when assessing cardiovascular risk.


Assuntos
Doenças Cardiovasculares , Glucose , Masculino , Feminino , Humanos , Ácido Úrico , Triglicerídeos , Estudos Retrospectivos , Teorema de Bayes , Glicemia/metabolismo , Biomarcadores , Fatores de Risco , Ponte de Artéria Coronária/efeitos adversos , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/etiologia
8.
Sci Total Environ ; 891: 164190, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37196954

RESUMO

The hormetic response of microbes to cadmium (Cd) is often observed in soil, but the mechanisms are unclear. In this study, we proposed a novel perspective of hormesis that successfully explained the temporal hermetic response of soil enzymes and microbes, and the variation of soil physicochemical properties. Several soil enzymatic and microbial activities were stimulated by 0.5 mg·kg-1 exogenous Cd, but inhibited at higher Cd dosages. The phenomena suggested the hormetic response to 0.5 mg·kg-1 Cd was highly generalizable concerning soil enzymes and microbial activity. However, the response disappeared after incubation for >10 days. Soil respiration was also initially enhanced by exogenous Cd and decreased after consumption of labile soil organic matter. The metagenomic results revealed Cd stimulation of genes involved in labile soil organic matter decomposition. Additionally, Cd enriched the antioxidant enzymatic activity and abundances of the corresponding marker genes, rather than genes involved in the efflux-mediated heavy metal resistance. The microbes enhanced their primary metabolism to make up the energy gaps, with hormesis evident. The hormetic response disappeared after the labile compounds in soil were exhausted. Overall, this study illustrates the dose-dependence and temporal variation of stimulants and provides a novel and feasible strategy for the study of Cd in soil microorganisms.


Assuntos
Metais Pesados , Poluentes do Solo , Cádmio/análise , Hormese , Solo/química , Poluentes do Solo/análise , Microbiologia do Solo
9.
J Colloid Interface Sci ; 627: 151-159, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35842965

RESUMO

The application value of silicon-based anodes has not been fully realized due to the âˆ¼ 300% volume expansion and poor electronic conductivity. In present study, mesoporous Si/C (MP-Si/C) composite with nanosized primary particles of 30-50 nm and pore diameter of 20-40 nm was proposed, which displays superior Li storage properties. Firstly, Polyacrylic acid (PAA) was applied to fulfill in-situ carbon coating and inhibit the particle growth of SiO2 generated from tetraethyl orthosilicate (TEOS) in stöber reaction. Secondly, Mg gas was introduced to create nano-sized Si with meso-pores and three-dimensional carbon network via the gas-cutting effect. The cycling stability and rate capability were both significantly enhanced with capacity of 671 mAh/g after 400 cycles and 593 mAh/g after 500 cycles at 2 A/g and 4 A/g, respectively, which was highly relevant to the selection of carbon source PAA and its corresponding carbon coating and Mg reduction effect. Moreover, this method bypasses the use of costly nano-silicon, which provides inspiration for the commercialization of silicon-based anodes.

10.
Cell Rep ; 39(9): 110884, 2022 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-35649375

RESUMO

Muscle regeneration is known to be defective under diabetic conditions. However, the underlying mechanisms remain less clear. Adult quiescent muscle satellite cells (MuSCs) from leptin-receptor-deficient (i.e., db/db) diabetic mice are defective in early activation in vivo, but not in culture, suggesting the involvement of pathogenic niche factors. Elevated extracellular adenosine (eAdo) and AMP (eAMP) are detected under diabetic conditions. eAdo and eAMP potently inhibit cell cycle re-entry of quiescent MuSCs and injury-induced muscle regeneration. Mechanistically, eAdo and eAMP engage the equilibrative Ado transporters (ENTs)-Ado kinase (ADK)-AMPK signaling axis in MuSCs to inhibit the mTORC1-dependent cell growth checkpoint. eAdo and eAMP also inhibit early activation of quiescent fibroadipogenic progenitors and human MuSCs by the same mechanism. Treatment of db/db diabetic mice with an ADK inhibitor partially rescues the activation defects of MuSCs in vivo. Thus, both ADK and ENTs represent potential therapeutic targets for restoring the regenerative functions of tissue stem cells in patients with diabetes.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Adenosina , Animais , Células Cultivadas , Humanos , Camundongos , Camundongos Endogâmicos , Músculos
11.
Jt Dis Relat Surg ; 33(1): 57-85, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35361081

RESUMO

OBJECTIVES: This meta-analysis aims to assess tranexamic acid (TXA) effectiveness and safety in lumbar surgery. PATIENTS AND METHODS: Renewals of randomized-controlled trials (RCTs) were conducted utilizing databases of medical literature such as PubMed, China Science and Technology Journal Database, Cochrane Library, China National Knowledge Infrastructure (CNKI), and EMBASE to compare principal and safety endpoints. The risk ratio (RR), standard mean difference (SMD), and 95% confidence intervals (CIs) were calculated. For the evaluation of the quality of the included studies, the Cochrane risk of bias criteria were utilized by two authors. RESULTS: In total, 49 articles were enrolled that included 4,822 patients. Of the patients, 2,653 were administered TXA and 2,169 were in the control group. The findings indicated that TXA was capable of significantly lowering postoperative blood loss (PBL), transfusion rate, transfusion volume, total blood loss (TBL), intraoperative blood loss (IBL), and drainage compared to the control group. Besides, hemoglobin (Hb) and hematocrit (Hct) values were higher in the TXA group compared to the control group. As the safety endpoints, TXA significantly reduced D-dimer levels compared to the control group; however, both TXA and control groups had no significant variations in deep venous thrombosis (DVT). Subgroup analysis was administrated according to the administration method of TXA and the operation type and intravenous and topical TXA were combined in the meta-analysis. CONCLUSION: This meta-analysis showed that TXA had the potential to significantly lower PBL, transfusion rate, transfusion volume, TBL, IBL, and drainage compared to the control group. Besides, Hb and Hct values were higher in the TXA group compared to the control group. Its hemostatic potential after lumbar spine surgery is trustworthy. It is still controversial in safety endpoints that TXA can significantly reduce D-dimer compared to the control group, without no significant variations in DVT in both the TXA and control groups.


Assuntos
Antifibrinolíticos , Ácido Tranexâmico , Administração Tópica , Antifibrinolíticos/efeitos adversos , Perda Sanguínea Cirúrgica/prevenção & controle , Transfusão de Sangue , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Ácido Tranexâmico/efeitos adversos
12.
J Colloid Interface Sci ; 606(Pt 1): 666-676, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34418754

RESUMO

Modifying separator with metal oxides has been considered as a strong strategy to inhibit the shuttling of soluble polysulfide in the lithium-sulfur battery (Li-S battery). Manganesedioxide (MnO2), one kind of transition metal oxide, is widely applied to decorate the PP (Polypropylene) separator. However, the fabrication by physical coating is always multistep and complicated. Here, we design a simple and fast method to chemically decorate separator. Based on the oxidizing property of acidic KMnO4 solution, the PP separator was oxidized and an ultrathin self-assembled MnO2 layer was directly constructed on one side of separator, by immersing in acidic KMnO4 solution for only 1 h. The self-assembled MnO2 layer has the synergistic effect of adsorption and catalytic conversion on polysulfides, which can effectively inhibit the shuttle effect. It can also help battery to maintain excellent electrochemical kinetics in the electrochemical cycle and maintain the effective recycling of active substances. As a result, the shuttling of polysulfide is greatly prohibited by this novel functional separator, and cycling stability is outstandingly improved, with a low-capacity decaying of 0.058% after 500 cycles at 0.5C. The rapid and simple modification method proposed in this study has a certain reference value for the future large-scale application of lithium-sulfur battery.

13.
J Biol Chem ; 297(4): 101166, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34487763

RESUMO

Hibernation is an example of extreme hypometabolic behavior. How mammals achieve such a state of suspended animation remains unclear. Here we show that several strains of type 2 diabetic mice spontaneously enter into hibernation-like suspended animation (HLSA) in cold temperatures. Nondiabetic mice injected with ATP mimic the severe hypothermia analogous to that observed in diabetic mice. We identified that uric acid, an ATP metabolite, is a key molecular in the entry of HLSA. Uric acid binds to the Na+ binding pocket of the Na+/H+ exchanger protein and inhibits its activity, acidifying the cytoplasm and triggering a drop in metabolic rate. The suppression of uric acid biosynthesis blocks the occurrence of HLSA, and hyperuricemic mice induced by treatment with an uricase inhibitor can spontaneously enter into HLSA similar to that observed in type 2 diabetic mice. In rats and dogs, injection of ATP induces a reversible state of HLSA similar to that seen in mice. However, ATP injection fails to induce HLSA in pigs due to the lack of their ability to accumulate uric acid. Our results raise the possibility that nonhibernating mammals could spontaneously undergo HLSA upon accumulation of ATP metabolite, uric acid.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Hibernação , Ácido Úrico/metabolismo , Trifosfato de Adenosina/genética , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/farmacologia , Animais , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patologia , Cães , Hiperuricemia/genética , Hiperuricemia/metabolismo , Hiperuricemia/patologia , Masculino , Camundongos , Camundongos Knockout , Ratos , Trocadores de Sódio-Hidrogênio/genética , Trocadores de Sódio-Hidrogênio/metabolismo
14.
ACS Appl Mater Interfaces ; 13(34): 40995-41003, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34415716

RESUMO

Li-rich Mn-based cathodes have attracted much attention due to their high capacity stemming from anion redox above 4.5 V. However, the continuous activation of Li2MnO3 in Li-rich Mn-based materials, which correlates with O2 release and TM migration, is usually unfavorable to structural stability. Herein, based on a gas-solid interface reaction, we tackle this continuous activation phenomenon by restricting the capacity release of Li2MnO3 via NH4HCO3 treatment in the Li1.2Ni0.36Mn0.44O2 cathode. After modification, oxygen vacancies associated with the spinel phase are introduced on the surface. The 4 mol % NH4HCO3-modified material's capacity starts at 182 mAh g-1 at 1 C instead of increasing from 173 to 186 mAh g-1 for 25 cycles in the pristine material. Meanwhile, it also exhibits an excellent capacity retention of 93.24% after 200 cycles (at 1 C), with a small voltage decay rate of 1.19 mV cycle-1.

15.
Angew Chem Int Ed Engl ; 60(43): 23248-23255, 2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34405936

RESUMO

Li-rich layered oxides with high capacity are expected to be the next generation of cathode materials. However, the irreversible and sluggish anionic redox reaction leads to the O2 loss in the surface as well as the capacity and voltage fading. In the present study, a simple gas-solid treatment with ferrous oxalate has been proposed to uniformly coat a thin spinel phase layer with oxygen vacancy and simultaneously realize Fe-ion substitution in the surface. The integration of oxygen vacancy and spinel phase suppresses irreversible O2 release, prevents electrolyte corrosion, and promotes Li-ion diffusion. In addition, the surface doping of Fe-ion can further stabilize the structure. Accordingly, the treated Feox-2 % cathode exhibits superior capacity retention of 86.4 % and 85.5 % at 1 C and 2 C to that (75.3 % and 75.0 %) of the pristine sample after 300 cycles, respectively. Then, the voltage fading is significantly suppressed to 0.0011 V per cycle at 2 C especially. The encouraging results may play a significant role in paving the practical application of Li-rich layered oxides cathode.

16.
Chemistry ; 27(13): 4249-4269, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33073440

RESUMO

Nickel-rich layered transition metal oxides are considered as promising cathode candidates to construct next-generation lithium-ion batteries to satisfy the demands of electrical vehicles, because of the high energy density, low cost, and environment friendliness. However, some problems related to rate capability, structure stability, and safety still hamper their commercial application. In this Review, beginning with the relationships between the physicochemical properties and electrochemical performance, the underlying mechanisms of the capacity/voltage fade and the unstable structure of Ni-rich cathodes are deeply analyzed. Furthermore, the recent research progress of Ni-rich oxide cathode materials through element doping, surface modification, and structure tuning are summarized. Finally, this review concludes by discussing new insights to expand the field of Ni-rich oxides and promote practical applications.

17.
Chem Commun (Camb) ; 56(36): 4886-4889, 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32236258

RESUMO

Phase transition occurring during cycling plays a fundamentally important role in the cycling performance of nickel-rich cathodes. Here, splitting of two O3 phases, rather than the often observed O1 phases in the conventional LiCoO2 electrode, was discovered in LiNi0.85Co0.10Mn0.05O2 at a high-voltage region (>4.6 V). Such degradation could be mitigated via Al doping.

18.
ACS Appl Mater Interfaces ; 12(20): 22971-22980, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32347703

RESUMO

The insulating nature of sulfur/Li2S and heavy shuttle effect of lithium polysulfides (LiPSs) hinder the commercialization of lithium-sulfur (Li-S) batteries. To address such issues, we designed and synthesized a porous carambola-like N,S-doped carbon framework embedded with Mo2C particles (designed as N,S-Mo2C/C-ACF) as the interlayer material to block the polysulfide shuttle and it behaves as a catalytic mediator for LiPS conversion. The modified separator of polypropylene functionalized by N,S-Mo2C/C-ACF, showing ultrafast wetting ability to the electrolyte and high lithium ion (Li+) conductivity, proves to be highly effective for inhibiting the polysulfide shuttle and simultaneously promoting the reutilization of adsorbed LiPSs. When used in Li-S batteries by coupling with a Super P/sulfur cathode, over a wide temperature range of 5-55 °C, the as-fabricated batteries delivered excellent rate capability and long cycle stability. Especially, at a high rate of 5 C, the discharge capacities of 405, 630, and 670 mA h gs-1 were achieved when tested at 5, 30, and 55 °C, respectively. The remarkable wide temperature performance is appealing for extended practical application of Li-S batteries.

19.
J Appl Crystallogr ; 52(Pt 5): 1222-1232, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31636524

RESUMO

Cryocooling for macromolecular crystallography is usually performed via plunging the crystal into a liquid cryogen or placing the crystal in a cold gas stream. These two approaches are compared here for the case of nitro-gen cooling. The results show that gas stream cooling, which typically cools the crystal more slowly, yields lower mosaicity and, in some cases, a stronger anomalous signal relative to rapid plunge cooling. During plunging, moving the crystal slowly through the cold gas layer above the liquid surface can produce mosaicity similar to gas stream cooling. Annealing plunge cooled crystals by warming and recooling in the gas stream allows the mosaicity and anomalous signal to recover. For tetragonal thermolysin, the observed effects are less pronounced when the cryosolvent has smaller thermal contraction, under which conditions the protein structures from plunge cooled and gas stream cooled crystals are very similar. Finally, this work also demonstrates that the resolution dependence of the reflecting range is correlated with the cooling method, suggesting it may be a useful tool for discerning whether crystals are cooled too rapidly. The results support previous studies suggesting that slower cooling methods are less deleterious to crystal order, as long as ice formation is prevented and dehydration is limited.

20.
Nat Commun ; 10(1): 51, 2019 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-30604775

RESUMO

The brain-specific angiogenesis inhibitor (BAI) subfamily of adhesion G protein-coupled receptors (aGPCRs) plays crucial roles in diverse cellular processes including phagocytosis, myoblast fusion, and synaptic development through the ELMO/DOCK/Rac signaling pathway, although the underlying molecular mechanism is not well understood. Here, we demonstrate that an evolutionarily conserved fragment located in the C-terminal cytoplasmic tail of BAI-aGPCRs is specifically recognized by the RBD-ARR-ELMO (RAE) supramodule of the ELMO family scaffolds. The crystal structures of ELMO2-RAE and its complex with BAI1 uncover the molecular basis of BAI/ELMO interactions. Based on the complex structure we identify aGPCR-GPR128 as another upstream receptor for the ELMO family scaffolds, most likely with a recognition mode similar to that of BAI/ELMO interactions. Finally, we map disease-causing mutations of BAI and ELMO and analyze their effects on complex formation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Angiogênicas/genética , Proteínas do Citoesqueleto/genética , Domínios e Motivos de Interação entre Proteínas/genética , Receptores Acoplados a Proteínas G/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/isolamento & purificação , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Angiogênicas/química , Proteínas Angiogênicas/isolamento & purificação , Proteínas Angiogênicas/metabolismo , Animais , Linhagem Celular , Cristalografia por Raios X , Proteínas do Citoesqueleto/química , Proteínas do Citoesqueleto/isolamento & purificação , Proteínas do Citoesqueleto/metabolismo , Células HEK293 , Humanos , Camundongos , Mutagênese , Mutação , Neoplasias/genética , Receptores Acoplados a Proteínas G/química , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA