Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
1.
J Biomed Inform ; 149: 104555, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38008241

RESUMO

The COVID-19 pandemic has sparked numerous discussions on social media platforms, with users sharing their views on topics such as mask-wearing and vaccination. To facilitate the evaluation of neural models for stance detection and premise classification, we organized the Social Media Mining for Health (SMM4H) 2022 Shared Task 2. This competition utilized manually annotated posts on three COVID-19-related topics: school closures, stay-at-home orders, and wearing masks. In this paper, we extend the previous work and present newly collected data on vaccination from Twitter to assess the performance of models on a different topic. To enhance the accuracy and effectiveness of our evaluation, we employed various strategies to aggregate tweet texts with claims, including models with feature-level (early) fusion and dual-view architectures from the SMM4H 2022 Task 2 leaderboard. Our primary objective was to create a valuable dataset and perform an extensive experimental evaluation to support future research in argument mining in the health domain.


Assuntos
COVID-19 , Mídias Sociais , Humanos , Pandemias , Mineração de Dados , Coleta de Dados
2.
Chemistry ; 25(47): 10976-10994, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31041811

RESUMO

Silicon (Si) is a promising candidate for high-capacity anode materials owing to its high theoretical capacity (3579 mAh g-1 ), low working voltage, and wide natural abundance, although its huge volume variation during charge/discharge processes always results in a short cycling life. Polymer binders play a vital role in improving the cycling performance of Si-based anodes, although traditional polyvinylidene difluoride cannot fulfil the requirements owing to its weak van der Waals forces with the Si surface. Recently, polymer binders constructed by dynamic bonds have been developed, which are reported to allow high-energy-density electrodes with improved electrochemical performance. With dynamic bonds including hydrogen bonding, ionic bonding, and host-guest interactions, these polymer binders possess self-healing capabilities and enhanced mechanical performance, achieving a tremendous advance in addressing the capacity fading of Si-based anodes. In this review, we will summarize the research progress of polymer binders constructed with dynamic bonds, and the challenges for their real applications in advanced Li-ion batteries will also be discussed.

3.
Phys Chem Chem Phys ; 17(20): 13451-6, 2015 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-25929515

RESUMO

A cost-efficient and scalable method is designed to prepare a SiOx-C composite with superior cyclability and excellent rate performance. The glucose addition in a two-step way induces a hierarchical structure, where individual SiOx nanoparticles are wrapped by a conductive carbon layer and these agglomerated particles are further wrapped by a carbon shell functioning as an electrolyte blocking layer. Instrumental analysis indicates that the SiOx domains are comprised of SiO2 and SiO. The SiOx-C anode exhibits a high reversible specific capacity of 674.8 mA h g(-1) after 100 cycles at 100 mA g(-1) with a capacity retention of about 83.5%. The excellent electrochemical performance is due to the hierarchical structure, the well-dispersed conductive carbon network, and the Li2O and Li4SiO4 generated in the initial discharge process, all of which can immensely relieve the volume expansion induced by the lithiation of silicon. This hierarchical SiOx-C composite has a promising prospect of practical application given its adequate storage capacity, good cycling stability, commercially available materials and simple equipment.

4.
ACS Appl Mater Interfaces ; 16(10): 12374-12384, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38414436

RESUMO

Metallic lithium (Li) is considered as the "Holy Grail" anode material for next-generation energy storage systems due to its extremely high theoretical capacity and low electrochemical potential. Before the commercialization of the Li electrode, dendritic Li growth and the unstable solid electrolyte interphase layer should be conquered. Herein, a hybrid covalent adaptable polymer network (HCAPN) is prepared via the random copolymerization of poly(ethylene glycol) methyl ether methacrylate and -acetoacetoxyethyl methacrylate, followed by chemical cross-linking with polyethylenimine (PEI) and amine-modified silicon dioxide (SiO2). Such a hybrid network, where PEI and amine-modified SiO2 formed a vinylogous urethane-based dynamic covalent bond with the copolymer, respectively, shows improved mechanical properties, solvent resistance, and excellent healability/recyclability. As the protecting layer on the Li electrode, the assembled HCAPN@Li||HCAPN@Li symmetric cell shows a long cycle life of 800 h with low overpotential at a current density of 1 mA cm-2, and superior electrochemical performance can be achieved in the HCAPN@Li||LiFePO4 full cell (capacity retention of 77% over 400 cycles at 1.5 C) and HCAPN@Li||NCM811 cell (capacity retention of 79% after 300 cycles). Surface morphology analysis is also performed for physical insight into their role as protecting layer. This work provides a new perspective for constructing a hybrid dynamic covalent network-based polymer protecting layer for inhibiting Li dendrite growth.

5.
ACS Appl Mater Interfaces ; 15(19): 23765-23776, 2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37158416

RESUMO

Lithium (Li) metal is a highly promising anode material for next-generation high-energy-density batteries, while Li dendrite growth and the unstable solid electrolyte interphase layer inhibit its commercialization. Herein, a chemically grafted hybrid dynamic network (CHDN) is rationally designed and synthesized by the 4,4'-thiobisbenzenamine cross-linked poly(poly(ethylene glycol) methyl ether methacrylate-r-glycidyl methacrylate) and (3-glycidyloxypropyl) trimethoxysilane-functionalized SiO2 nanoparticles, which is utilized as a protective layer and hybrid solid-state electrolyte (HSE) for stable Li-metal batteries. The presence of a dynamic exchangeable disulfide affords self-heability and recyclability, and the chemical attachment between SiO2 nanoparticles and the polymer matrix enables the homogeneous distribution of inorganic fillers and mechanical robustness. With integrated flexibility, fast segmental dynamics, and autonomous adaptability, the as-prepared CHDN-based protective layer enables superior electrochemical performance in half cells and full cells (capacity retention of 83.7% over 400 cycles for the CHDN@Li/LiFePO4 cell at 1 C). Furthermore, benefiting from intimate electrode/electrolyte interfacial contact, CHDN-based solid-state cells deliver excellent electrochemical performance (capacity retention of 89.5% over 500 cycles for the Li/HSE/LiFePO4 cell at 0.5 C). In addition, the Li/HSE/LiFePO4 pouch cell exhibits superior safety, even exposing various physical damage conditions. This work thereby provides a fresh insight into a rational design principle for dynamic network-based protective layers and solid-state electrolytes for battery applications.

6.
ACS Appl Mater Interfaces ; 14(22): 26014-26023, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35608943

RESUMO

Although numerous studies on polymeric protective films to stabilize lithium (Li)-metal electrodes have been reported, the construction of self-healing polymers that enables the long-term operation of Li-metal batteries (LMBs) at relatively low temperatures has rarely been demonstrated. Herein, a highly stretchable, autonomous self-healable, and ionic-conducting polymer network (SHIPN) is synthesized as an efficient protective film for LMBs. The network backbone, synthesized from copolymerization of poly(ethylene glycol)-mono-methacrylate (PEGMMA) and 2-[[(butylamino)carbonyl]oxy]ethyl acrylate (BCOE), is chemically cross-linked via diisocyanate. With SHIPN-modified electrodes, enhanced electrochemical performance can be achieved in Li/Cu, Li/Li, and Li/LiFePO4 (Li/LFP) cells. The SHIPN@Li/LFP cell delivers a capacity retention of 85.6% after 500 cycles at 5 °C, resulting from the low-temperature self-healability of SHIPN. In full cells with a high-mass-loading LFP cathode (∼17 mg cm-2), the capacity retention is at least 300% higher than that with a bare Li electrode. Further physical characterizations of electrodes confirm the effect of SHIPN in enhancing the interfacial stability and suppressing Li dendrite growth. Our results will provide insights into rationally designing soft and hybrid materials toward stable LMBs at different temperatures.

7.
IEEE Trans Ultrason Ferroelectr Freq Control ; 69(11): 3102-3107, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35030078

RESUMO

Piezoelectric ceramics have been widely used in high precision sensors such as vibration detection, but piezoelectric accelerometers in high-temperature applications are very rare. We prepared ( 1- x ) BiFeO3- x BaTiO3-0.0035MnO2-0.001Li2CO3(BF- x BT) ceramics by a solid state approach, and investigated the effect of BT content( x ) on the phase structure, microstructure, dielectric properties, ferroelectric properties, piezoelectric properties, temperature stability, and especially the sensitivity of the piezoelectric accelerometer. The crystal structure of the sample is pure perovskite structure with the MPB (R and P phases) locating in a composition range of 0.28 ≤ x ≤ 0.32 for BF-xBT ceramics, and the single R phase exist at . When x = 0.30, the ceramic presents both high Curie temperature and d33 . Notably, the sensitivity of BF-0.30BT piezoelectric accelerometer reaches the highest value of about 40 pC/g and shows an excellent stability until 400 °C, indicating that this material is a promising candidate for high-temperature piezoelectric accelerometer applications.


Assuntos
Cerâmica , Transdutores , Temperatura , Teste de Materiais , Análise de Falha de Equipamento , Desenho de Equipamento , Cerâmica/química , Acelerometria
8.
ACS Appl Mater Interfaces ; 14(50): 56110-56119, 2022 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-36490324

RESUMO

With many reported attempts on fabricating single-ion conducting polymer electrolytes, they still suffer from low ionic conductivity, narrow voltage window, and high cost. Herein, we report an unprecedented approach on improving the cationic transport number (tLi+) of the polymer electrolyte, i.e., single-ion conducting polymeric protective interlayer (SIPPI), which is designed between the conventional polymer electrolyte (PVEC) and Li-metal electrode. Satisfied ionic conductivity (1 mS cm-1, 30 °C), high tLi+ (0.79), and wide-area voltage stability are realized by coupling the SIPPI with the PVEC electrolyte. Benefiting from this unique design, the Li symmetrical cell with the SIPPI shows stable cycling over 6000 h at 3 mA cm-2, and the full cell with the SIPPI exhibits stable cycling performance with a capacity retention of 86% over 1000 cycles at 1 C and 25 °C. This incorporated SIPPI on the Li anode presents an alternative strategy for enabling high-energy density, long cycling lifetime, and safe and cost-effective solid-state batteries.

9.
Front Pediatr ; 9: 626323, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34368023

RESUMO

Objective: To explore the effectiveness and safety of rituximab (RTX) for steroid-dependent or frequently relapsing nephrotic syndrome via a systematic review and meta-analysis. Methods: All the literature about RTX therapy for childhood nephrotic syndrome (NS) on PubMed, Web of Science, Cochrane Library, EMBASE, and Chinese biomedical literature database published before November 1, 2019, were conducted and selected according to the preset criteria. The Cochrane bias risk assessment tool was used to evaluate the quality of the literature included. The outcome data were analyzed by RevMan 5.3 software. Results: There were six RCT studies that met the inclusion criteria with a moderate quality after evaluation. At the end of the treatment, the relapse rate of NS in the RTX group reduced significantly when compared with that in the control group [odds ratio (OR) = 0.11, 95% confidence interval (CI) (0.03, 0.43), p = 0.001]. The number of patients in the RTX group used less steroid or/and calcineurin inhibitors significantly than that in the control group [OR = 0.05, 95% CI (0.01, 0.28), p = 0.0007]. For children who were steroid-dependent, RTX treatment significantly reduced the dosage of the steroid, compared with that in control [standardized mean difference (SMD) = -1.49, 95% CI (-2.00, -0.99), p < 0.00001]. There was no significant reduction in protein excretion between the two groups [SMD = -0.33, 95% CI (-0.71, 0.04), p = 0.08]. Fewer serious adverse reactions of RTX in the six studies were reported and most adverse events were mild. Conclusion: RTX is effective and safe for children with steroid-dependent or frequently relapsing nephrotic syndrome. Systematic Review Registration: Identifier: CRD 42020150933. https://www.crd.york.ac.uk/prospero/. This review has been registered to the PROSPERO on 27 Feb 2020.

10.
Front Pharmacol ; 12: 638724, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34512318

RESUMO

Background and Aims: Tacrolimus(TAC)-induced nephrotoxicity, which has a large individual variation, may lead to treatment failure or even the end-stage renal disease. However, there is still a lack of effective models for the early prediction of TAC-induced nephrotoxicity, especially in nephrotic syndrome(NS). We aimed to develop and validate a predictive model of TAC-induced tubular toxicity in children with NS using machine learning based on comprehensive clinical and genetic variables. Materials and Methods: A retrospective cohort of 218 children with NS admitted between June 2013 and December 2018 was used to establish the models, and 11 children were prospectively enrolled for external validation. We screened 47 clinical features and 244 genetic variables. The changes in urine N- acetyl- ß-D- glucosaminidase(NAG) levels before and after administration was used as an indicator of renal tubular toxicity. Results: Five machine learning algorithms, including extreme gradient boosting (XGBoost), gradient boosting decision tree (GBDT), extremely random trees (ET), random forest (RF), and logistic regression (LR) were used for model generation and validation. Four genetic variables, including TRPC6 rs3824934_GG, HSD11B1 rs846910_AG, MAP2K6 rs17823202_GG, and SCARB2 rs6823680_CC were incorporated into the final model. The XGBoost model has the best performance: sensitivity 75%, specificity 77.8%, accuracy 77.3%, and AUC 78.9%. Conclusion: A pre-administration model with good performance for predicting TAC-induced nephrotoxicity in NS was developed and validated using machine learning based on genetic factors. Physicians can estimate the possibility of nephrotoxicity in NS patients using this simple and accurate model to optimize treatment regimen before administration or to intervene in time after administration to avoid kidney damage.

11.
J Phys Chem B ; 110(51): 25769-74, 2006 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-17181219

RESUMO

Mg1.8La0.2Ni hydrogen storage alloy was ball-milled with Ni powder, leading to the formation of a nanocrystalline and amorphous microstructure with particle sizes less than 50 nm in diameter. Each sample was examined by transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). This structure was beneficial for the reduction of electrochemical impedance, as well as significant improvement of its discharge capacity, cycle life, and rate capability for electrochemical hydrogen storage in an alkaline solution. When the molar ratio (x) of Ni over Mg1.8La0.2Ni was equal to 2, the dehydriding capacity reached 2.55 wt % from electrochemical pressure-temperature isotherms (P-C-T). It was in good agreement with its initial discharge capacity, 716 mA*h/[g of (Mg1.8La0.2Ni)], observed from the electrochemical charge and discharge process. After 50 cycles, its discharge capacity still reached 381 mA*h/[g of (Mg1.8La0.2Ni)]. Further results showed that this composite had a promising high rate capability. At the current density of 1200 mA/g its discharge capacity reached 48% of its initial capacity.

12.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 31(2): 274-6, 2006 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-16706132

RESUMO

OBJECTIVE: To discuss the pathologic features, treatment and prognosis of the children with isolated proteinuria (IP). METHODS: Twenty-one children with IP were enrolled according to their renal biopsy and were followed up for 0.5 to 10 years. RESULTS: Renal biopsy was performed in all children. Among them 13 were mesangial proliferation glomerulonephritis (MsPGN) (including 3 minor, 6 moderate, and 4 severe ones), 2 minimal change nephritis (MCN), 3 IgA nephropathy (IgAN) (1 in Grade I and 2 in Grade II), 2 focal segmemtal glomerulosclerosis (FSGS) and 1 endocapillary proliferative glomerulonephritis (EnPGN). Interstitial changes could be found in MsPGN and FSGS mostly, presenting interstitial fibrosis, infiltration of inflammatory cells, atrophy of renal tubule, and the vacuolar degeneration of epithelia. All children accepted the medical treatment except the EnPGN case. Fifteen children recovered with no relapse; proteinuria persisted in 3 severe MsPGN and FSGS cases; 2 got the impaired renal function accompanied by persistent proteinuria; and 1 had hypertension. CONCLUSION: The different degrees of renal damage can be found in all IP children who have persistent proteinuria. Most patients can get good outcome after aggressive therapies. However, the prognosis of those with severe MsPGN and FSGS was not so optimistic, and some reno-protective treatments should be given to postpone the deterioration of the renal function.


Assuntos
Glomerulonefrite Membranoproliferativa/patologia , Rim/patologia , Proteinúria/patologia , Adolescente , Biópsia por Agulha , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Prognóstico , Proteinúria/etiologia
13.
Zhonghua Er Ke Za Zhi ; 43(2): 109-12, 2005 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-15833166

RESUMO

OBJECTIVE: Glucocorticoid (GC) is the first therapeutic choice of primary nephrotic syndrome (PNS). The response to GC treatment is an important indicator for the outcome of PNS children. Children with GC-resistant PNS present with incomplete or no response to GC, and may herald the progression to end-stage renal failure. However, the detailed mechanism of GC-resistance or GC-sensitive effect in these PNS children has not been clearly elucidated. The previous study by the authors indicated that there was increased expression of GR beta in PBMCs in GC-resistant children with PNS, and the over expression of GR beta resulted in GC resistance via influencing the ability of GR alpha nuclear translocation. To elucidate the relationship between GR beta expression in renal and in PBMCs and the effect of glucocorticoid on glucocorticoid-resistance children with PNS, the expression of GR alpha and GR beta in renal tissue and in PBMCs were detected by immunohistochemistry. METHODS: Forty children with PNS were divided into two groups, GC-resistant group(20) and GC-sensitive group(20), the expression of GR alpha and GR beta in renal intrinsic cells and in PBMCs were measured with the immunohistochemistry technique. A semiquantitative score was used to evaluate the injury degree of the glomeruli and tubulointerstitium. RESULTS: Compared with GC-sensitive group, the glomerular pathologic scores (6.91 +/- 1.98) and renal tubular pathologic scores (7.12 +/- 1.62) in GC- resistant group were significantly different (P < 0.01, respectively). GR alpha expressions of renal tissue and PBMCs were higher in the control group (58.3 +/- 2.6, 59.1 +/- 7.2) than those in the GC-sensitive group (40.2 +/- 7.2 and 36.6 +/- 5.1, P < 0.01, respectively) and GC-resistant group (35.0 +/- 8.2 and 36.4 +/- 6.6, P < 0.01, respectively). GR beta expressions of renal tissue and PBMCs were higher in the GC-resistant group (13.8 +/- 3.0 and 12.1 +/- 4.1) and in the GC-sensitive group (6.5 +/- 1.9 and 5.9 +/- 1.0) than that in control group (2.3 +/- 0.4 and 3.2 +/- 1.1, P < 0.01, respectively). GR beta expressions in renal tissue and PBMCs were higher in the GC-resistant group than that in the GC-sensitive group (P < 0.01). Compared with control group, GR beta expressions in PBMCs and in renal tissue were lower than those in mild renal lesion group (5.4 +/- 2.8, 6.46 +/- 2.50), midmedium renal lesion group (8.7 +/- 2.4 and 11.4 +/- 3.7) and (17.1 +/- 0.4 and 18.7 +/- 0.7) in severe renal lesion group (F = 5.8, 15.6, P < 0.01, respectively). GR beta expression of PBMCs had a positive correlation with GR beta expression of renal intrinsic cells (r = 0.651, P < 0.01). GR beta expressions by PBMCs and renal intrinsic cells were positively correlated with renal pathologic scores (r = 0.579 and 0.623, P < 0.01, respectively). CONCLUSION: GC-resistant children with PNS were related to the increased GR beta expression in PBMCs and renal intrinsic cells. There was no correlation between the GR alpha expressions in PBMCs and in renal intrinsic cells. Increased GR beta expression might decrease the effect of GC via inhibiting the activity of GR alpha.


Assuntos
Glucocorticoides/uso terapêutico , Síndrome Nefrótica/tratamento farmacológico , Adolescente , Criança , Pré-Escolar , Resistência a Medicamentos , Feminino , Humanos , Glomérulos Renais/patologia , Túbulos Renais/patologia , Masculino , Síndrome Nefrótica/patologia , Receptores de Glucocorticoides/análise
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa