Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 744
Filtrar
1.
Biomaterials ; 279: 121180, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34768152

RESUMO

Cancer stem cells (CSCs) present grand challenges for triple-negative breast cancer (TNBC). Conventional chemotherapy drugs, including Camptothecin (CPT), not only cannot eradicate CSCs but also foster a suppressive immune microenvironment for the initiation and proliferation of CSCs. Herein, we report a novel prodrug CPT-SS-NLG919 (CN) and its nanoformulation CN@PLA-HES-FA (CN@PHF), which potently suppress CSCs by regulating CSCs niche in murine TNBC 4T1 tumors. Via inducing immunogenic cell death (ICD) and simultaneous inhibiting indoleamine 2, 3-dioxygenase (IDO), CN and CN@PHF promote DC maturation, decrease Treg cells, mitigate tryptophan consumption, and reduce the amount of IL-6, IL-13, and TGF-ß, converting CSCs niche to a hostile condition for CSCs to live in and eliminating CSCs efficiently, thereby inducing efficient tumor inhibition in 4T1 tumor models. Our work represents a new paradigm of eliminating CSCs by regulating tumor immune microenvironment and suggests that CN and its nanoformulation CN@PHF are promising candidates for the treatment of intractable TNBC.

2.
Oxid Med Cell Longev ; 2021: 5598291, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34765083

RESUMO

A novel herbal extract-loaded gel containing several biofunctional extracts, including green tea, Zingiber officinale Rosc, Phyllanthus emblica, and salicylic acid, was developed for acne vulgaris. These natural raw materials were blended with suitable dosages of gelatin and carboxymethyl cellulose (CMC) to produce a biocompatible herbal gel. The physical chemistry properties of the hydrogel were determined by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), rheometry, and scanning electron microscopy (SEM), and the hydrogel showed good mechanical and morphological characteristics. The herbal extract-loaded hydrogel mimicked extracellular matrix properties and showed good antioxidant and anti-inflammatory properties and various advantages, serving as a potential wound dressing material because of its high moisture retention ability, wound exudate absorption behavior, and biocompatibility. It exhibited moderate-high antioxidative and anti-inflammatory qualities that were important for dermis wound closure. The clinical trial results showed that most patients experienced moderate to high healing rates, and four of twenty-four individuals (16.67%) had recovery area ratios greater than 80%. This herbal extract-loaded hydrogel has effective ingredients and excellent mechanical properties as a bioactive dressing agent for acne treatment.

3.
Nanoscale ; 13(46): 19399-19411, 2021 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-34755744

RESUMO

Imaging-guided diagnosis and chemo-photothermal combination therapy have promising applications for the treatment of cancer. Nevertheless, the accurate diagnosis and efficient treatment of tumors are not yet satisfactory. Herein, a tumor targeting DiR loaded cisplatin-icodextrin prodrug nanoparticle, with selective drug release, was fabricated as a multifunctional theranostic nanoplatform for chemo-photothermal combination therapy. By loading DiR into the hydrophobic domain of folic acid-icodextrin-polycaprolactone (FA-ICO-PCL, FIP) and cisplatin-icodextrin-polycaprolactone (Pt-ICO-PCL, PtIP) co-assembly, the resultant DiR@(PtIP + FIP) (DPtFIP) NPs had a diameter of around 70 nm and showed excellent tumor targeting ability and negligible side effects. Moreover, the DPtFIP NPs achieved real-time NIR fluorescence imaging of solid tumors with high contrast. By the accurate tumor imaging, local laser irradiation dramatically enhanced the chemotherapy for triple-negative breast cancer. Such a biocompatible nanotherapeutic holds great potential for tumor diagnosis and imaging-guided combinational cancer therapy.

4.
Biomed Pharmacother ; 145: 112416, 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34781147

RESUMO

Phytochemicals are plant-derived bioactive compounds, which have been widely used for therapeutic purposes. Due to the poor water-solubility, low bioavailability and non-specific targeting characteristic, diverse classes of nanocarriers are utilized for encapsulation and delivery of bio-effective agents. Cell-derived nanovesicles (CDNs), known for exosomes or extracellular vesicles (EVs), are biological nanoparticles with multiple functions. Compared to the artificial counterpart, CDNs hold great potential in drug delivery given the higher stability, superior biocompatibility and the lager capability of encapsulating bioactive molecules. Here, we provide a bench-to-bedside review of CDNs-based nanoplatform, including the bio-origin, preparation, characterization and functionalization. Beyond that, the focus is laid on the therapeutic effect of CDNs-mediated drug delivery for natural products. The state-of-art development as well as some pre-clinical applications of using CDNs for disease treatment is also summarized. It is highly expected that the continuing development of CDNs-based delivery systems will further promote the clinical utilization and translation of phyto-nanomedicines.

5.
BMJ Open ; 11(11): e046682, 2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34794984

RESUMO

OBJECTIVES: Polycyclic aromatic hydrocarbons (PAHs) have been proven to be a risk factor for cardiovascular disease in coke oven workers, and increased plasma viscosity is a signal for higher risk of catching up cardiovascular disease. We want to explore whether the plasma viscosity is affected by the concentration of PAHs. DESIGN: Our study is a cross-sectional dose-response study. SETTING: Participants in this study came from a coke plant in Taiyuan, Shanxi. PARTICIPANTS: We used data of 693 coke oven workers in Taiyuan. PRIMARY AND SECONDARY OUTCOME MEASURES: We assumed that plasma viscosity would increase as the concentration of PAHs metabolites in urine increases. We found that 2-hydroxyfluorene (OHFLU2) and plasma viscosity have a stable linear relationship in different statistical methods. RESULTS: We found that plasma viscosity increased by 1.14 (mPa.s,30/s) for each ng/mL of 2-OHFLU urinary (correlation coefficient range: 0.54-1.74, p<0.05). CONCLUSIONS: The results of this study could provide evidence for coke oven workers to prevent cardiovascular disease by checking whether plasma viscosity is elevated.

6.
Brain Res Bull ; 178: 97-107, 2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34801649

RESUMO

BACKGROUND: Ischemic injury is a common nervous disease associated with the dysfunction of human brain microvascular endothelial cells (HBMECs). Circular RNAs (circRNAs) have key roles in ischemic injury. This research aims to investigate the role and mechanism of circ_0090002 in ischemic injury. METHODS: HBMECs were stimulated by oxygen-glucose deprivation (OGD). Circ_0090002, microRNA-186-5p (miR-186-5p), and homologous to the E6-AP Carboxyl Terminus domain E3 ubiquitin ligase 1 (HECTD1) levels were detected by quantitative reverse transcription polymerase chain reaction or Western blotting. Cell viability and migration were determined using Cell Counting Kit-8 (CCK-8) assay and wound healing assay. Flow cytometry and caspase-3 activity assay were used for apoptosis analysis. The oxidative injury and cell toxicity were assessed by reactive oxygen species (ROS) and lactic dehydrogenase (LDH) release assay kits, respectively. The interaction was investigated by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays. In vivo assay was performed in rats. RESULTS: Circ_0090002 expression was reduced in OGD-stimulated HBMECs. Circ_0090002 overexpression attenuated OGD-induced reduction of cell viability and migration but elevation of apoptosis, oxidative stress and cell toxicity. Circ_0090002 sponged miR-186-5p and miR-186-5p overexpression reversed the protective role of circ_0090002 against the OGD-induced cell injury. MiR-186-5p targeted HECTD1miR-186-5p knockdown mitigated cell damages in by increasing HECTD1 level in OGD-treated HBMECs. Circ_0090002 could upregulate the HECTD1 expression via regulating miR-186-5p. Circ_0090002 inhibited infarct volume of brain in rats. CONCLUSION: These results demonstrated that circ_0090002 mitigated OGD-induced cell dysfunction in HBMECs by targeting the miR-186-5p/HECTD1 axis.

7.
Transl Oncol ; 15(1): 101284, 2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34839107

RESUMO

BACKGROUND: Ovarian cancer is one of the most common female cancers, with a high incidence worldwide. Aberrant expression of low-density lipoprotein (LDL) receptor-related protein 8 (LRP8) and microRNA (miR)-362-3p is involved in the pathogenesis of different cancers. METHODS: We aimed to elucidate the underlying mechanism of the miR-362-3p-LRP8 axis in ovarian cancer. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to examine miR-362-3p and LRP8 expression in ovarian cancer tissues and cells. The luciferase assay was used to determine the relationship between miR-362-3p and LRP8. The function of overexpression of miR-362-3p and LRP8 was determined by assessing the cell viability using the cell counting kit 8 (CCK-8) assay, proliferation using 5'­bromo-2'-deoxyuridine (BrdU) assay, migration using wound healing assay, invasion using transwell assay, and the protein expression levels of matrix metalloproteinase (MMP)-2, MMP9, and integrin α5 or ß1 using western blotting assays in ovarian cancer cells. RESULTS: miR-362-3p expression levels were decreased in ovarian cancer tissues and cells and negatively correlated with LRP8 levels. Overexpression of miR-362-3p dramatically repressed cell growth. Furthermore, overexpression of LRP8 significantly facilitated the proliferation, migration, and invasion of ovarian cancer cells, which counteracted the inhibitory effect of miR-362-3p on ovarian cancer cell growth. CONCLUSIONS: We reported that miR-362-3p hampered cell growth by repressing LRP8 expression in ovarian cancer cells. Our results provide new insights into ovarian cancer, involving both miR-362-3p and LRP8, which can be used as potential biomarkers for the treatment of ovarian cancer.

8.
Front Public Health ; 9: 730611, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34760863

RESUMO

Introduction: As of June 7, 2021, the outbreak of Coronavirus Disease 2019 (COVID-19) has spread to more than 200 countries. The global number of reported cases is more than 172.9 million, with more than 3.7 million deaths, and the number of infected individuals is still growing rapidly. Consequently, events and activities around the world were canceled or postponed, and the preparation for sporting events were greatly challenged. Under such circumstances, about 11,000 athletes from ~206 countries are arriving in Tokyo for the 32nd Summer Olympic Games. Therefore, it is urgently necessary to assess the occurrence and spread risk of COVID-19 for the Games. Objectives: To explore effective prevention and control measures for COVID-19 in large international events through simulations of different interventions according to risk assessment. Methods: We used a random model to calculate the number of initial infected patients and used Poisson distribution to determine the number of initial infected patients based on the number of countries involved. Furthermore, to simulate the COVID-19 transmission, the susceptible-exposed-symptomatic-asymptomatic-recovered-hospitalized (SEIARH) model was established based on the susceptible-exposed-infectious-recovered (SEIR) mathematical model of epidemic diseases. According to risk assessment indicators produced by different scenarios of the simulated interventions, the risk of COVID-19 transmission in Tokyo Olympic Games was assessed. Results: The current COVID-19 prevention measures proposed by the Japan Olympic Committee need to be enhanced. And large-scale vaccination will effectively control the spread of COVID-19. When the protective efficacy of vaccines is 78.1% or 89.8%, and if the vaccination rate of athletes reaches 80%, an epidemic prevention barrier can be established.


Assuntos
COVID-19 , Esportes , Humanos , Medição de Risco , SARS-CoV-2 , Tóquio/epidemiologia
9.
Scand J Gastroenterol ; : 1-10, 2021 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-34726133

RESUMO

BACKGROUND: The present study aimed to assess the survival, incidence, and characteristics of secondary primary lung cancer (SPLC) after esophageal cancer (EC-LC). METHODS: The patients with esophageal cancer (EC) who developed SPLC and patients with first primary lung cancer (LC-1) were retrospectively reviewed in the Surveillance, Epidemiology, and End Results 18 registries covering 2000-2016. Overall survival and characteristics were compared between patients with EC-LC and patients with LC-1. The independent relation between a history of EC and death was evaluated by calculating hazard ratios in multivariate Cox regression analysis propensity score-matching analysis, and multiple imputation for cases with missing information. RESULTS: In comparison with the general population, the patients with EC had a higher risk for developing secondary primary lung cancer (SIR =1.86, 95% confidence interval (CI): 1.69-2.05). A history of EC was found to be an independent risk factor of death for lung squamous carcinoma (LUSC) and lung adenocarcinoma (LUAD) patients in localized stage based on multivariate Cox regression analysis, propensity score-matching analysis and multiple imputation. CONCLUSIONS: There is a significantly increased risk of secondary primary lung cancer in EC survivors and a history of EC adversely affects overall survival in individuals who subsequently develop localized LUSC and LUAD. Clinicians should moderately strengthen lung tissue protection during the management of EC patients.

10.
Horm Metab Res ; 53(11): 738-745, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34740275

RESUMO

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age. Metformin is introduced for treatment of women with PCOS, and the beneficial effects of exercise in women with PCOS are found for a range of outcomes. Our aim is to compare the effects of metformin plus exercise with exercise intervention in PCOS on clinical, anthropometric, metabolic, and psychological parameters. MEDLINE, EMBASE, Web of Science and China National Knowledge Infrastructure were searched for studies. Nine studies were considered eligible for inclusion. The meta-analysis reveals that metformin offers additive benefits to exercise, leading to modest improvements in menstrual cycles, hyperandrogenism, and abdominal fat.

11.
ACS Omega ; 6(43): 29243-29253, 2021 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-34746612

RESUMO

Casein (CS) and graphene oxide (GO) were employed for the fabrication of a casein/graphene oxide (CS/GO) aerogel by vacuum freeze drying. Fourier transform infrared spectroscopy, scanning electron microscopy, surface area and micropore analysis (BET), and thermogravimetric analysis were used to characterize the specific surface area, structure, thermal stability, and morphology of the CS/GO aerogel. The influence of experimental parameters such as the GO mass fraction in the aerogel, metering of the adsorbent, pH, contact time, and temperature on the adsorption capacity of the CS/GO aerogel on methylene blue (MB) was also investigated. According to Langmuir isotherm determination, the maximum removal rate of MB from the CS/GO aerogel was 437.29 mg/g when the temperature was 293 K and pH was 8. Through kinetic and thermodynamic studies, it is found that adsorption follows a pseudo-second-order reaction model and is also an exothermic and spontaneous process.

12.
Reprod Biomed Online ; 2021 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-34799276

RESUMO

RESEARCH QUESTION: What is the mechanism of hypermethylation of runt-related transcription factor 3 (RUNX3) in the eutopic endometrium of endometriosis as biomarker in the malignant transformation of endometriosis? DESIGN: Methylation-specific polymerase chain reaction was used to analyse the methylation status of RUNX3 in endometriosis-associated ovarian cancer (EAOC). Primary eutopic endometrial stromal cells (ESC) were isolated from the uteri of patients with ovarian endometriosis. After RUNX3 knockdown by RNA interference technology or ESC treated with oestradiol, the proliferation and invasion ability were evaluated in ESC by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and transwell assays. RESULTS: The frequency of methylation of RUNX3 in neoplastic tissue in the EAOC group was significantly higher than that in the ectopic endometrium of the endometriosis group (P < 0.001), and the frequency of methylation of RUNX3 in the eutopic endometrium of the EAOC group was significantly higher than that in the endometriosis group (P < 0.001). However, there was no significant difference in the eutopic endometrium when compared between the endometriosis group and the control endometrium group (P = 0.233). Silencing RUNX3 promoted the proliferation and invasion of ESC (P < 0.001 and P < 0.001). Following intervention with oestrogen, it was observed that the oestradiol group showed higher levels of RUNX3 methylation (P < 0.001) and DNA methyltransferase 1 (DNMT1) mRNA and protein expression (P < 0.001 and P < 0.001), and lower RUNX3 mRNA and protein expression when compared with the ESC group (P < 0.001 and P < 0.001). CONCLUSION: This study demonstrated that hypermethylation of the RUNX3 was related to the malignant transformation of endometriosis and that this process was related to corresponding changes in the eutopic endometrium. Furthermore, the 'oestrogen-DNMT1' signalling pathway may induce the hypermethylation of RUNX3 to promote the malignant transformation of endometriosis.

13.
ACS Appl Mater Interfaces ; 13(45): 53646-53658, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34748304

RESUMO

Intrinsic tumor microenvironment (TME)-related therapeutic resistance and nontumor-specific imaging have limited the application of imaging-guided cancer therapy. Herein, a TME-responsive MnO2-based nanoplatform coupled with turn-on and always-on fluorescence probes was designed through a facile biomineralization method for imaging-guided photodynamic/chemodynamic/photothermal therapy (PDT/CDT/PTT). After the tumor-targeting delivery of the AuNCs@MnO2-ICG@AS1411 (AMIT) nanoplatform via aptamer AS1411, the TME-responsive dissociation of MnO2 generated sufficient O2 and Mn2+ with the consumption of GSH for improving PDT efficacy and Fenton-like reaction-mediated CDT. Simultaneously, the released small-sized ICG and AuNCs facilitated PDT and PTT efficacy via the deep tumor penetration. Moreover, the turn-on fluorescence of AuNCs revealed the real-time TME-responsive MnO2 degradation process, and the always-on ICG fluorescence enabled the in situ monitoring of the payload distribution in vitro and in vivo. The AMIT NPs also provided magnetic resonance and thermal imaging guidance for the enhanced PDT, CDT, and PTT. Therefore, this all-in-one nanosystem provides a simple and versatile strategy for multiple imaging-guided theranostic applications.

14.
Cells ; 10(10)2021 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-34685720

RESUMO

Different types of cells, such as endothelial cells, tumor-associated fibroblasts, pericytes, and immune cells, release extracellular vesicles (EVs) in the tumor microenvironment. The components of EVs include proteins, DNA, RNA, and microRNA. One of the most important functions of EVs is the transfer of aforementioned bioactive molecules, which in cancer cells may affect tumor growth, progression, angiogenesis, and metastatic spread. Furthermore, EVs affect the presentation of antigens to immune cells via the transfer of nucleic acids, peptides, and proteins to recipient cells. Recent studies have also explored the potential application of EVs in cancer treatment. This review summarizes the mechanisms by which EVs regulate melanoma development, progression, and their potentials to be applied in therapy. We initially describe vesicle components; discuss their effects on proliferation, anti-melanoma immunity, and drug resistance; and finally focus on the effects of EV-derived microRNAs on melanoma pathobiology. This work aims to facilitate our understanding of the influence of EVs on melanoma biology and initiate ideas for the development of novel therapeutic strategies.

15.
Front Immunol ; 12: 732125, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34603310

RESUMO

Immunotherapy, a chemotherapy-free process, has emerged as a promising therapeutic strategy to prolong the overall survival (OS) of patients with non-small-cell lung cancer (NSCLC). However, effective stratification factors for immunotherapy remain unclear. The purpose of this study was to discuss the potential stratification factors of NSCLC immunotherapy using immune checkpoint inhibitors (ICIs) by integrating genomic profiling and tumor lesion-type information. In this study, 344 patients with NSCLC, whose clinical and tissue (including metastatic and primary lesions) mutation information was available, were included. The potential gene mutation status for predicting the outcomes of immunotherapy was screened by comparing the difference in mutation frequency between responders and non-responders. Our results indicated that the potential predictors of immunotherapy were significantly different, especially between patients with TP53(+) (including metastatic and primary lesions) and TP53(-) (including metastatic and primary lesions). According to this classification, patients with NSCLC who suggested immunotherapy had a higher OS than those who did not (25 months vs. 7 months, P < 0.0001, hazard ratio = 0.39). Collectively, this study provides a new perspective for screening immunotherapy predictors in NSCLC, suggesting that the TP53 mutation status and source of biopsy tissue should be considered during the development of immunotherapy biomarkers.

16.
Inorg Chem ; 60(22): 17258-17267, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34708656

RESUMO

Plasmonics, especially the localized surface plasmon resonance (LSPR) in non-noble metal bismuth nanoparticles (Bi NPs), and its spectral features and applications have stimulated increasing research interest in recent years. However, the lack of mature methods to prepare Bi NPs with a well-controlled size and/or shape significantly limits the experimental investigations concerning the LSPR optical properties. Herein, we realize the size-tunable synthesis of nearly monodisperse spherical Bi NPs through a thiolate pyrolysis reaction in solution. The instantaneous thermolysis of a layered molecular intermediate, bismuth dodecanethiolate [Bi(SC12H25)3], results in a classical LaMer mechanism for the nucleation and growth of Bi NPs, allowing for a precise size control from 65 to 205 nm in the average diameter. The diameter tunability enables a systematic study on the size dependence of LSPR optical properties of Bi NPs, and we observe rich ultraviolet-visible-near-infrared spectral responses arising from the LSPR absorption and scattering of Bi NPs as their size varies, which will greatly benefit the light harvesting and manipulation in the solar spectrum. Furthermore, we find that a complete oxidation occurs to Bi NPs under air flow at the temperature when they melt and accordingly generate metastable tetragonal-phase ß-Bi2O3 NPs that show an optical band gap of 2.15 eV and interesting temperature-dependent ß â†’ α → δ → (γ + ß) polymorphic transitions.

17.
J Pharmacol Sci ; 147(4): 348-357, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34663517

RESUMO

Kaempferol, a representative flavonoid constituent of Sanguisorba officinalis, promotes melanogenesis, but the underlying mechanisms remain unknown. Here, we evaluated the effects of kaempferol on melanocytes morphology and behavior and determined the mechanisms regulating kaempferol-induced pigmentation. We observed that kaempferol increased melanin contents and dendritic length and stimulated melanocyte migration both in vitro and vivo. It significantly enhanced the expression of microphthalmia-associated transcription factor (MITF) and downstream enzymes of melanin biosynthesis-tyrosinase (TYR), tyrosinase-related protein (TRP-1), and dopachrome tautomerase (DCT). It also induced melanosome maturation (increased stage III and IV melanosomes) and melanin transfer to dendritic tips; this was evidenced as follows: kaempferol-treated melanocytes exhibited the perimembranous accumulation of HMB45-positive melanosomes and increased the expression of Rab27A, RhoA, and Cdc42, which improved melanosome transport to perimembranous actin filaments. These results jointly indicated that kaempferol promotes melanogenesis and melanocyte growth. Additionally, kaempferol stimulated the phosphorylation of P38/ERK MAPK and downregulated p-PI3K, p-AKT, and p-P70s6K expression. Pre-incubation with P38 (SB203580) and ERK (PD98059) signaling inhibitors reversed the melanogenic and dendritic effects and MITF expression. PI3K/AKT inhibitor augmented kaempferol-induced melanin content and dendrite length. In summary, kaempferol regulated melanocytes' dendritic growth and melanosome quantity, maturation, and transport via P38/ERK MAPK and PI3K/AKT signaling pathways.

18.
ACS Appl Mater Interfaces ; 13(40): 47449-47457, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34596373

RESUMO

A novel 3.3 V copper-lithium battery using a copper foil as the cathode is a potential candidate for next-generation energy storage system due to its simple manufacturing process. However, the cross-over of copper ions from the cathode to the anode limits the reversibility of the battery. Herein, we suppress self-discharge and migration of copper ions in the cell using a commercial polypropylene separator with a coating of polyacrylic acid (PAA), a chelating polymer. Fourier transform infrared spectroscopy confirms that the PAA layer traps the copper ions and prevents them from passing through. The addition of barium titanate nanoparticles into the PAA layer further enhances ionic transfer through the separator and reduces polarization of the cell at high current rates during charge and discharge. The use of a chelating agent with an inorganic filler as a coating layer on the separator is a cost-effective way to improve reversibility and round-trip efficiency of copper-lithium batteries.

19.
J Phys Chem Lett ; 12(42): 10353-10358, 2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34665965

RESUMO

Two-dimensional Mg2C, one of the typical representative MXene materials, is attracting lots of attention due to its outstanding properties. In this study, we find the thermal conductivity of monolayer Mg2C is more than 2 orders of magnitude lower than graphene and is even lower than MoS2 despite the relatively lighter atoms of Mg and C. Based on the comparative analysis with graphene, silicene, and MoS2, the underlying mechanism is found lying in the unique arrangement of atoms (lighter atoms in the middle plane) and large electronegativity difference in Mg2C. The phonon anharmonicity is strong due to the resonant bonding. In addition, dual band gaps emerge in the phonon dispersion of Mg2C, which limit the phonon-phonon scattering and reduce the phonon relaxation time. This study reveals a new mechanism responsible for low thermal conductivity, which would be helpful for designing thermal functional materials and pave the way for applications in thermoelectrics.

20.
Ying Yong Sheng Tai Xue Bao ; 32(10): 3521-3530, 2021 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-34676713

RESUMO

We explored the seasonal dynamics and climate responses of radial variation of Chinese fir, we continuously monitored intra-annual stem radial size changes with the automated dendrometers in central Jiangxi Province in 2016 and 2017. We analyzed daily and seasonal dynamics of radial variations, and their Spearman correlations with climatic factors. We found that the diurnal radial variations had a pattern of contraction during the day and expansion at night. The growth onset in 2017 was one month earlier than that in 2016, whereas the continuous tree water deficit in the dry season caused the cessation one month early. During the main growing season (from April to September), the radial increment was significantly positively correlated with precipitation and relative humidity but negatively correlated with photosynthetically active radiation and vapor pressure deficit in both wet and dry seasons. However, the correlation for tree water deficit was opposite to stem radial increment. Severe water deficit significantly enhanced the impacts of soil water content on stem radial variation in the dry season. Moisture condition was always the key factor affecting stem radial variation of Chinese fir. Appropriate measures such as increasing soil water content could promote stem radial growth during summer drought.


Assuntos
Cunninghamia , Secas , Clima , Estações do Ano , Árvores
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...