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1.
Nat Commun ; 12(1): 1264, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627654

RESUMO

The recent development of imputation methods enabled the prediction of human leukocyte antigen (HLA) alleles from intergenic SNP data, allowing studies to fine-map HLA for immune phenotypes. Here we report an accurate HLA imputation method, CookHLA, which has superior imputation accuracy compared to previous methods. CookHLA differs from other approaches in that it locally embeds prediction markers into highly polymorphic exons to account for exonic variability, and in that it adaptively learns the genetic map within MHC from the data to facilitate imputation. Our benchmarking with real datasets shows that our method achieves high imputation accuracy in a wide range of scenarios, including situations where the reference panel is small or ethnically unmatched.

2.
Cancer Sci ; 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33629464

RESUMO

The G-protein-coupled receptor 126 (GPR126) may play an important role in tumor development. although its role remains poorly understood. We found that GPR126 had higher expression in most colorectal cancer cell lines than in normal colon epithelial cell lines, and higher expression levels in colorectal cancer tissues than in normal adjacent colon tissues. GPR126 knockdown induced by shRNA inhibited cell viability and colony formation in HT-29, HCT116, and LoVo cells, decreased BrdU incorporation into newly synthesized proliferating HT-29 cells, led to an arrest of cell cycle progression at the G1 phase in HCT-116 and HT-29 cells, and suppressed tumorigenesis of HT-29, HCT116, and LoVo cells in nude mouse xenograft models. GPR126 knockdown engendered decreased transcription and translation of histone deacetylase 2 (HDAC2), previously implicated in the activation of GLI1 and GLI2 in the Hedgehog signaling pathway. Ectopic expression of HDAC2 in GPR126-silenced cells restored cell viability and proliferation, GLI2 luciferase reporter activity, partially recovered GLI2 expression, and reduced the cell cycle arrest. HDAC2 regulated GLI2 expression and, along with GLI2, it bound to the PTCH1 promoter, as evidenced by a chip assay with HT-29 cells. Purmorphamine, a hedgehog agonist, largely restored the cell viability and expression of GLI2 proteins in GPR126-silenced HT-29 cells, whereas GANT61, a hedgehog inhibitor, further enhanced the GPR126 knockdown-induced inhibitory effects. Our findings demonstrate that GPR126 regulates colorectal cancer cell proliferation by mediating the expression of HDAC2 and GLI2; therefore, it may represent a suitable therapeutic target for colorectal cancer treatment.

3.
Nat Commun ; 12(1): 1098, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33597505

RESUMO

Many diseases exhibit population-specific causal effect sizes with trans-ethnic genetic correlations significantly less than 1, limiting trans-ethnic polygenic risk prediction. We develop a new method, S-LDXR, for stratifying squared trans-ethnic genetic correlation across genomic annotations, and apply S-LDXR to genome-wide summary statistics for 31 diseases and complex traits in East Asians (average N = 90K) and Europeans (average N = 267K) with an average trans-ethnic genetic correlation of 0.85. We determine that squared trans-ethnic genetic correlation is 0.82× (s.e. 0.01) depleted in the top quintile of background selection statistic, implying more population-specific causal effect sizes. Accordingly, causal effect sizes are more population-specific in functionally important regions, including conserved and regulatory regions. In regions surrounding specifically expressed genes, causal effect sizes are most population-specific for skin and immune genes, and least population-specific for brain genes. Our results could potentially be explained by stronger gene-environment interaction at loci impacted by selection, particularly positive selection.

4.
Bioinspir Biomim ; 2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33621963

RESUMO

We provide a corrigendum for the paper "The effect of variable stiffness of tuna-like fish body and fin on swimming performance" (2021 Bioinspir. Biomim. 16 016003).

5.
Phys Med Biol ; 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33631735

RESUMO

An effective registration framework between preoperative 3D computed tomography and intraoperative 2D X-ray images is crucial in image-guided therapy. In this paper, a novel 2D/3D hierarchical registration framework via principal-directional Fourier transform operator (HRF-PDFTO) is proposed. First, a principal-direction Fourier transform operator (PDFTO) was established to obtain the in-plane translation and rotation invariance. Then, an initial free template-matching approach based on PDFTO was utilized to avoid initial value assignment and expand the capture range of registration. Finally, the hierarchical registration framework, HRF-PDFTO, was proposed to reduce the dimensions of the registration search space from n^6 to n^2. The experimental results demonstrated that the proposed HRF-PDFTO has good performance with an accuracy of 0.72 mm, and a single registration time of 16 s, which improves the registration efficiency by ten times. Consequently, the HRF-PDFTO can meet the accuracy and efficiency requirements of 2D/3D registration in related clinical applications.

6.
Bioorg Chem ; 109: 104694, 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-33601141

RESUMO

Cancer treatment is one of the major public health issues in the world. Tetrandrine (Tet) and fangchinoline (d-Tet) are two bis-benzyl isoquinoline alkaloids extracted from Stephania tetrandra S. Moore, and their antitumor activities have been confirmed. However, the effective dose of Tet and d-Tet were much higher than that of the positive control and failed to meet clinical standards. Therefore, in this study, as a continuation of our previous work to study and develop high-efficiency and low-toxic anti-tumor lead compounds, twenty new Tet and d-Tet derivatives were designed, synthesized and evaluated as antitumor agents against six cancer cell lines (H460, H520, HeLa, HepG-2, MCF-7, SW480 cell lines) and BEAS-2B normal cells by CCK-8 analysis. Ten derivatives showed better cytotoxic effects than the parent fangchinoline, of which 4g showed the strongest cell growth inhibitory activity with an IC50 value of 0.59 µM against A549 cells. Subsequently, the antitumor mechanism of 4g was studied by flow cytometry, Hoechst 33258, JC-1 staining, cell scratch, transwell migration, and Western blotting assays. These results showed that compound 4g could inhibit A549 cell proliferation by arresting the G2/M cell cycle and inhibiting cell migration and invasion by reducing MMP-2 and MMP-9 expression. Meanwhile, 4g could induce apoptosis of A549 cells through the intrinsic pathway regulated by mitochondria. In addition, compound 4g inhibited the phosphorylation of PI3K, Akt and mTOR, suggesting a correlation between blocking the PI3K/Akt/mTOR pathway and the above antitumor activities. These results suggest that compound 4g may be a future drug for the development of new potential drug candidates against lung cancer.

7.
BMC Pregnancy Childbirth ; 21(1): 164, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627077

RESUMO

BACKGROUND: Labor pain during childbirth can have devastating effects on the progress of labor, mother, and fetus. Consequently, the management of labor pain is crucial for the well-being of the mother and fetus. Transcutaneous electrical nerve stimulation (TENS) is a non -pharmacological analgesic technique. It uses a low-voltage electrical current to activate descending inhibitory systems in the central nervous system to relieve pain. This study aimed to determine the effects of TENS therapy in the first stage of labor. METHODS: In this single-blind randomized controlled trial, we screened low-risk pregnant women who anticipated spontaneous vaginal delivery. Women were assigned (1:1) to either the experimental group (received TENS therapy in the first stage of labor) or the control group (received routine obstetric care). The women, midwives, and researchers working in the gynecology and obstetric department were aware of the treatment group, but statisticians analysis the data were blinded. The primary outcome was labor pain intensity, assessed by visual analog scale (VAS) immediately after the randomization, at 30, 60, and 120 min after TENS therapy, and 2-24 h post-delivery. We used SPSS 21.0 software in data analysis. An independent sample t-test compared the mean VAS scores and labor duration between groups. A Chi-square test was employed to compare categorical variables between the groups. A significant level of ≤0.05 was statistically significant. RESULTS: A total of 326 pregnant women were eligible: experimental group (n = 161) and control group (n = 165). The experimental group had statistically significantly lower mean VAS scores at a different time (30, 60, and 120 min post-intervention and 2-24 h post-delivery) than the control group (p < 0.001). The experimental group demonstrated a statistically significant shorter duration of the active labor phase than the control group (p < 0.001). CONCLUSION: This study indicates that TENS can be used as a non-pharmacological therapy to reduce pain and shorten the active labor phase. TRIAL REGISTRATION: ISRCTN registry, ISRCTN23857995 . Registered on 11/12/2020, 'retrospectively registered.

8.
J Fish Dis ; 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33577719

RESUMO

Cyprinid herpesvirus 2 (CyHV-2), a member of the genus Cyprinivirus in the family Alloherpesviridae, has attracted worldwide attention because it causes severe disease and high mortality in crucian carp and goldfish. In this study, we focus on mRNA, protein and viral miRNA expression profiles in C. auratus gibelio caudal fin (GiCF) cells infected with CyHV-2, using high-throughput sequence techniques and TMT-labelled analyses. The results revealed that 156 virus genes were differentially expressed during the infection. Among these differentially expressed genes, 7 viral genes were significantly up-regulated and 28 were significantly down-regulated at 96 hpi (hours post-infection) vs 48 hpi. Besides, a total of 78 viral proteins, including a large number of membrane proteins and capsid proteins associated with the viral assembly, were successfully detected by using proteome analysis. Furthermore, a total of 225,143,474 raw reads were generated from cDNA library of CyHV-2-infected GiCF cells using high-throughput sequencing technology. Following annotation and secondary structure prediction, 10 viral miRNAs were found as significantly modulated in CyHV-2-infected GiCF cells (2 down-regulated and 8 up-regulated). Finally, the CyHV-2 genes (orf19, orf23, orf118, orf121, orf127) targeted by the viral miRNA CyHV-2-KT-635 identified in this study, were predicted and validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR), and the regulation of CyHV-2-KT-635 on orf121 protein expression was verified by western blotting assay. Taken together, this study provides a valuable basis for further research on the expression of virus genes during CyHV-2 replication and the molecular mechanisms by which miRNA may regulate CyHV-2 virus.

9.
Med Biol Eng Comput ; 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33559862

RESUMO

Accurate segmentation of the right ventricle (RV) from cardiac magnetic resonance imaging (MRI) images is an essential step in estimating clinical indices such as stroke volume and ejection fraction. Recently, image segmentation methods based on fully convolutional neural networks (FCN) have drawn much attention and shown promising results. In this paper, a new fully automatic RV segmentation method combining the FC-DenseNet and the level set method (FCDL) is proposed. The FC-DenseNet is efficiently trained end-to-end, using RV images and ground truth masks to make a per-pixel semantic inference. As a result, probability images are produced, followed by the level set method responsible for smoothing and converging contours to improve accuracy. It is noted that the iteration times of the level set method is only 4 times, which is due to the semantic segmentation of the FC-DenseNet for RV. Finally, multi-object detection algorithm is applied to locate the RV. Experimental results (including 45 cases, 15 cases for training, 30 cases for testing) show that the FCDL method outperforms the U-net + level set (UL) and the level set methods that use the same dataset and the cardiac functional parameters are computed robustly by the FCDL method. The results validate the FCDL method as an efficient and satisfactory approach to RV segmentation.

10.
Bull Environ Contam Toxicol ; 106(2): 363-369, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33439273

RESUMO

Smelting activities are an important source of heavy metals in soil. More seriously, oral ingestion of crops growing in contaminated soil potentially cause harmful effects on human health. The main purpose of this study is to apply the in vitro model (PBET) and Monte Carlo Simulation (MSC) to the health risk assessment process in order to more accurately and realistically evaluate health risks of residents eating contaminated potato. Results indicated in the raw and cooked potato, the bioaccessibility of Pb was 65.9% and 74.5%, and that of Cd was 79.6% and 61.7%, respectively. Additionally, the bioaccessible hazard quotient (BHQ) was less than the permitted level except for the BHQ of Pb for children. This indicated there wasn't potential non-carcinogenic risk for most potato-consumers but the dietary exposure risk for local children cannot be neglected. Sensitivity analysis showed that the bioaccessibility and ingestion rate appeared decisive with respect to potentially deleterious health effects.


Assuntos
Metais Pesados , Poluentes do Solo , Solanum tuberosum , Cádmio/análise , Criança , China , Monitoramento Ambiental , Humanos , Chumbo , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise
11.
Reprod Sci ; 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33449348

RESUMO

Endometriosis (EM) is a disease that involves active endometrial cell invasion and migration which is an important reason for infertility. Anoikis resistance is the most important prerequisite for EM, but the molecular mechanism is not yet clear. Kallistatin (KS) is one kind of serine protease inhibitors which had extensive biological function including anti-inflammatory, antioxidant stress, anti-angiogenesis, and anti-tumor. Our preliminary data showed that the level of KS in EM patients' endometrial tissue and blood were much lower than control (non-EM) patients without endometriosis. Interestingly, the decrease of KS is correlated with the severity of endometriosis. Moreover, kallistatin recombinant protein could increase the anoikis rate of ectopic endometrium cells (EESCs), and then inhibits its metastasis and invasion. Mechanically, our data show that the EESCs have lower intracellular reactive oxygen species (ROS) production and KS can elevate the ROS levels significantly. Further, KS modulate expression of MnSOD and caspase 3 signaling in EESCs grown in suspended conditions. These findings reveal novel mechanisms of KS in inducing anoikis and metastasis in EESCs, thus inhibiting EM progression by regulation of MnSOD and caspase 3 signaling. Our findings suggest that KS is a significant protein with prospects for application in EM.

12.
J Chem Phys ; 154(4): 044309, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33514086

RESUMO

In this work, we showcase applications of single-molecule Fano resonance (SMFR) measurements beyond the determination of molecular excitonic energy and associated dipole orientation. We use the SMFR measurement to probe the local influence of a man-made single chlorine vacancy on the molecular transition of a single zinc phthalocyanine, which clearly reveals the lifting-up of the double degeneracy of the excited states due to defect-induced configurational changes. Furthermore, time-trace SMFR measurements at different excitation voltages are used to track the tautomerization process in a free-base phthalocyanine. Different behaviors in switching between two inner-hydrogen configurations are observed with decreasing voltages, which helps to reveal the underlying tautomerization mechanism involving both the molecular electronic excited states and vibrational excited states in the ground state.

13.
J Sci Food Agric ; 2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-33491773

RESUMO

BACKGROUND: Purple corn (Zea mays L.) is one of the main economic crops in China and has been used in the treatment of cystitis, urinary infections and obesity. However, purple corncobs, the by-product remaining after processing and having an intense purple-black color, are normally disposed of as waste or used as animal feed. Therefore, to further expand the medicinal value of purple corncob, its content was analyzed and, after purification, the effect and mechanism of purified purple corncob anthocyanins (PPCCA) on CCl4 -induced chronic liver injury in mice were investigated. RESULTS: It was observed that the total anthocyanin content (TAC) from PPCCA (317.51 ± 9.30 mg cyanidin 3-O-glucoside (C-3-G) g-1 dry weight) was significantly higher than that from the purified purple corn seed anthocyanin (266.73 ± 3.67 mg C-3-G g-1 dry weight), of which C-3-G accounted for 90.6% and 90.4% of the TAC, respectively. Furthermore, compared with the CCl4 group, PPCCA treatment significantly reduced liver index, serum total bilirubin, alanine transaminase, aspartate transaminase and liver malondialdehyde levels, but increased liver superoxide dismutase activity. The pathological changes were also improved, such as more regular arrangement of hepatocytes, less swelling, and fewer vacuoles and apoptotic cells. Additionally, mechanistic studies showed that PPCCA downregulated the expression of Caspase-3, Bax and cytochrome P450 2E1 proteins in the liver and upregulated the expression of Bcl-2. CONCLUSION: These results demonstrated that PPCCA could ameliorate CCl4 -induced chronic liver injury by regulating oxidative stress and hepatocyte apoptosis pathways. © 2021 Society of Chemical Industry.

14.
Nat Commun ; 12(1): 508, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33479206

RESUMO

Thousands of human small and alternative open reading frames (smORFs and alt-ORFs, respectively) have recently been annotated. Many alt-ORFs are co-encoded with canonical proteins in multicistronic configurations, but few of their functions are known. Here, we report the detection of alt-RPL36, a protein co-encoded with human RPL36. Alt-RPL36 partially localizes to the endoplasmic reticulum, where it interacts with TMEM24, which transports the phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) precursor phosphatidylinositol from the endoplasmic reticulum to the plasma membrane. Knock-out of alt-RPL36 increases plasma membrane PI(4,5)P2 levels, upregulates PI3K-AKT-mTOR signaling, and increases cell size. Alt-RPL36 contains four phosphoserine residues, point mutations of which abolish interaction with TMEM24 and, consequently, alt-RPL36 effects on PI3K signaling and cell size. These results implicate alt-RPL36 as an upstream regulator of PI3K-AKT-mTOR signaling. More broadly, the RPL36 transcript encodes two sequence-independent polypeptides that co-regulate translation via different molecular mechanisms, expanding our knowledge of multicistronic human gene functions.


Assuntos
Proteínas de Membrana/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Ribossômicas/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Processamento Alternativo , Sequência de Aminoácidos , Sequência de Bases , Transporte Biológico , Membrana Celular/metabolismo , Regulação para Baixo , Retículo Endoplasmático/metabolismo , Células HEK293 , Humanos , Proteínas de Membrana/genética , Mutação , Fosfatidilinositol 4,5-Difosfato/metabolismo , Ligação Proteica , Proteínas Ribossômicas/genética
15.
J Fish Dis ; 2021 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-33400351

RESUMO

Bcl2 family proteins play a critical role in cell death or survival. BAX, the death-promoting protein of bcl2 family, mediated mitochondrial pathway inducing cells' apoptosis in mammal. MiRNAs have been implicated as negative regulators down-regulating genes' expression after post-transcriptional level. At present, little is known about the regulatory mechanism of miRNA on the Bcl2 family proteins during CyHV-2 infection in silver crucian carp (Carassius auratus gibelio). In this study, the ccBAX (silver crucian carp BAX) gene was cloned and expressed, and polyclonal antibodies were raised in mouse against the purified ccBAX-GST fusion protein. The structure analysis indicated that ccBAX protein included four conserve domains (BH1, BH2, BH3 and transmembrane domains) and the expression of ccBAX protein occurred throughout the cells. Furthermore, two miRNAs (miR-124 and miRNA-29b) were identified to negatively regulate ccBAX gene expression in GiCF cell. miR-124 was found to suppress the expression of WT-ccBAX (wild type), but not the MT-ccBAX (mutant). Overall, the results demonstrated that the expression of the ccBAX gene was significantly down-regulated by miR-124 in silver crucian carp (Carassius auratus gibelio) during CyHV-2 infection.

16.
Biomaterials ; 265: 120392, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32992116

RESUMO

The large-scale utilization of nanotechnology depends on public and consumer confidence in the safety of this new technology. Studying the interaction of nanoparticles with immune cells plays a vital role in the safety assessment of nanomedicine. Although some researches have indicated that the immune cells undergo severe interfere after phagocytosis of nanoparticles, the impact on immune system of the whole body are still unclear. Here, we use immune cells labeled transgenic zebrafish to study the mechanisms of nanoparticles on zebrafish immune cells. We demonstrate that gold nanoparticles (Au NPs) phagocytized by immune cells can reduce and retard the sensitivity of immune response, resulting nanoparticle-induced bluntness in immune cell (NIBIC). RNA-seq and functional analysis reveal that NIBIC is mainly induced by the inhibiting expression of chemokine receptor 5 (CCR5). Furthermore, PVP-modified Au NPs can eliminate NIBIC by inhibiting the cell phagocytosis. Our results highlight the potential risk for Au NPs in vivo and further the understanding of the mechanism of the interaction between Au NPs and the immune response. We should consider this factor in future material design and pay more attention to the process of using nanomedicines on immune diseases.

17.
J Agric Food Chem ; 69(1): 584-591, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33377764

RESUMO

According to a simple guest-replacement fluorescence turn-on mechanism, we constructed a fluorescent probe system based on cucurbit[10]uril (Q[10]) and protonated acridine (AD) to detect the pesticide dodine (DD). Formation of a homoternary inclusion complex AD2@Q[10] in both aqueous solution and solid state was studied by means of 1H NMR spectroscopy and X-ray crystallography. Although AD can emit strong fluorescence in aqueous solution, the homoternary inclusion complex AD2@Q[10] does not exhibit any fluorescence. Upon the addition of the pesticide DD into the aqueous solution of AD2@Q[10], the AD molecules in the Q[10] cavity are displaced by the pesticide DD, and strong fluorescence recovers. The fluorescent probe system based on Q[10] and AD provided a wide determination of DD from 0 to 4.0 × 10-5 mol·L-1 with a low limit of detection of 1.827 × 10-6 mol·L-1. The guest-replacement fluorescence turn-on mechanism is also confirmed by 1H NMR spectroscopy. Further, the fluorescent probe can directly detect DD residues in real agricultural products, and obvious fluorescence signal was observed under UV irradiation.

18.
Breast ; 55: 30-36, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33310633

RESUMO

PURPOSE: To characterize the incidence, risk factors and survival of patients with brain metastases at initial diagnosis of metastatic breast cancer (MBC) in China. METHODS: The China National Cancer Center database was used to identify 2087 MBC patients diagnosed between 2003 and 2015. Clinicopathological features, treatment and survival information were extracted. Multivariable logistic and Cox regression were performed to determine factors predictive of brain metastases at MBC diagnosis and survival, respectively. RESULTS: Brain metastases occurred in ninety patients (4.3%) at MBC diagnosis, and in 27 patients (2.5%), 42 patients (7.2%) and 21 patients (5.2%) with hormone receptor positive, human epidermal growth factor receptor 2 negative (HR + HER2-), HER2-positive and triple negative breast cancer (TNBC), respectively. HER2-positive subtype (OR = 2.38; 95% CI 1.40-4.04; p < 0.0001), TNBC subtype (OR = 1.89; 95% CI 1.02-3.51; p = 0.005), and metastases to all three sites of bone, liver and lungs (OR = 3.23; 95% CI 1.52-6.87; p = 0.002) were shown to increase the risk of BM at MBC diagnosis. Median survival after BM was 23.7 months. First-line tyrosine kinase inhibitors (TKI) improved survival compared to trastuzumab-based regimen (44.9 vs 35.4 months, p = 0.09). Factors that independently decreased BM death risk were ECOG<2, brain metastases only and multidisciplinary treatment. CONCLUSION: HER2-positive and TNBC subtypes have a higher incidence of BM at initial MBC diagnosis. Brain screening might be considered in patients with HER2-positive disease at MBC diagnosis, and further prospective randomized study is warranted.

19.
J Hazard Mater ; 401: 123818, 2021 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-33113743

RESUMO

The shrinking unreacted core model has been one of the most widely used models for the uncatalyzed reaction kinetics between the liquid/gas and the solid phases. However, the classical shrinking unreacted core model (CSUC model) is only applicable to spherical particles. Currently, the CSUC model has been used in many studies regardless of its applicable conditions. For example, Wang et al. (2016) investigated the decomposition kinetics of a rod-like residue and deduced the rate-controlling step using the CSUC model. The purpose of this comment is to propose a modified shrinking unreacted core model (shrinking cylinder model) suitable for materials with a high aspect ratio. The authors hope that this work will be helpful for kinetic analysis of rod-shaped and fiber-shaped materials in the uncatalyzed liquid/gas-solid reactions.

20.
Artigo em Inglês | MEDLINE | ID: mdl-33284602

RESUMO

Lithium-sulfur (Li-S) batteries are considered as one of the most prospective candidates for electric vehicles, due to their superior theoretical energy density and low cost. However, the issues of polysulfide ion (PS) shuttling and uncontrollable Li dendrite growth hindered their further application. Herein, a multifunctional nanoporous polybenzimidazole (PBI) membrane with well-controllable morphology was successfully designed and fabricated to address the aforementioned obstacles. In this design, the PBI membrane could offer strong chemical binding interaction with PS, thus applying dynamic adsorption toward PS as well as stable sulfur electrochemistry, which is further verified by experiments and density functional theory (DFT) simulation. Moreover, PBI membranes with high porosity and high electrolyte uptake capability can provide ample lithium storage space and abundant Li+ supplements to facilitate Li deposition and improve Li metal batteries' cyclic stability. Besides that, the PBI membrane has excellent mechanical and thermal stability and exclusive flame resistance, which guarantees the safety of the Li-S battery as well. As a result, Li-S batteries assembled with an as-developed PBI membrane demonstrated a remarkable rate capability of 780 mAh g-1 at 2C and an impressive reversible capacity of 523 mAh g-1 at 0.5C after 400 cycles, which is much higher than the commercial separators. More importantly, even with a lofty sulfur loading of 3 mg cm-2, a high discharge capacity of 744 mAh g-1 (capacity retention 93.96%, at 0.1C after 100 cycles) can also be achieved. Overall, the current study highlighted a robust material platform for stable, safe, and efficient multifunctional separators for high-performance Li-S batteries.

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