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1.
Clin Exp Dermatol ; 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38549552

RESUMO

Artificial Intelligence (AI) solutions for skin cancer diagnosis continue to gain momentum, edging closer towards broad clinical use. These AI models, particularly deep learning architectures, require large digital image datasets for development. This review provides an overview of the datasets used to develop AI algorithms and highlights the importance of dataset transparency for evaluation of algorithm generalisability across varying populations and settings. Current challenges for curation of clinically valuable datasets are detailed, which include dataset shifts arising from demographic variations and differences in data collection methodologies, along with inconsistencies in labelling. These shifts can lead to differential algorithm performance, compromise of clinical utility, and the propagation of discriminatory biases when developed algorithms are implemented in mismatched populations. Limited representation of rare skin cancers and minoritised groups in existing datasets are highlighted which can further skew algorithm performance. Strategies to address these challenges are presented, which include improving transparency, representation and interoperability. Federated learning and generative methods, which may improve dataset size and diversity without compromising privacy, are also examined. Lastly, we discuss model-level techniques which may address biases entrained through the use of datasets derived from routine clinical care. As the role of AI in skin cancer diagnosis becomes more prominent, ensuring the robustness of underlying datasets is increasingly important.

2.
Angew Chem Int Ed Engl ; 63(14): e202318236, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38323753

RESUMO

The controllable photocatalytic C-C coupling of methanol to produce ethylene glycol (EG) is a highly desirable but challenging objective for replacing the current energy-intensive thermocatalytic process. Here, we develop a metal-free porous boron nitride catalyst that demonstrates exceptional selectivity in the photocatalytic production of EG from methanol under mild conditions. Comprehensive experiments and calculations are conducted to thoroughly investigate the reaction mechanism, revealing that the OB3 unit in the porous BN plays a critical role in the preferential activation of C-H bond in methanol to form ⋅CH2OH via a concerted proton-electron transfer mechanism. More prominent energy barriers are observed for the further dehydrogenation of the ⋅CH2OH intermediate on the OB3 unit, inhibiting the formation of some other by-products during the catalytic process. Additionally, a small downhill energy barrier for the coupling of ⋅CH2OH in the OB3 unit promotes the selective generation of EG. This study provides valuable insights into the underlying mechanisms and can serve as a guide for the design and optimization of photocatalysts for efficient and selective EG production under mild conditions.

3.
Adv Mater ; : e2301772, 2023 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-37148503

RESUMO

The practical application of metalloid black phosphorus (BP) based anodes for potassium ion batteries is mainly impeded by its instability in air and irreversible/sluggish potassium storage behaviors. Herein, a 2D composite is purposefully conceptualized, where ultrathin BP nanodisks with Fe3 O4 nanoclusters are hybridized with Lewis acid iron (V)-oxo complex (FC) nanosheets (denoted as BP@Fe3 O4 -NCs@FC). The introduced electron coordinate bridge between FC and BP, and hydrophobic surface of FC synergistically assure that BP@Fe3 O4 -NCs@FC is ultrastable in humid air. With the purposeful structural and componential design, the resultant BP@Fe3 O4 -NCs@FC anode is endowed with appealing electrochemical performance in terms of reversible capacity, rate behavior, and long-duration cycling stability in both half and full cells. Furthermore, the underlying formation and potassium-storage mechanisms of BP@Fe3 O4 -NCs@FC are tentatively proposed. The in-depth insights here will provide a crucial understanding in rational exploration of advanced anodes for next-generation PIBs.

4.
BMC Geriatr ; 22(1): 333, 2022 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-35428266

RESUMO

INTRODUCTION: Aneurysmal subarachnoid haemorrhage (aSAH) is a condition with significant morbidity and mortality. Traditional markers of aSAH have established their utility in the prediction of aSAH outcomes while frailty markers have been validated in other surgical specialties. We aimed to compare the predictive value of frailty indices and markers of sarcopaenia and osteopaenia, against the traditional markers for aSAH outcomes. METHODS: An observational study in a tertiary neurosurgical unit on 51 consecutive patients with ruptured aSAH was performed. The best performing marker in predicting the modified Rankin scale (mRS) on discharge was selected and an appropriate threshold for the definition of frail and non-frail was derived. We compared various frailty indices (modified frailty index 11, and 5, and the National Surgical Quality Improvement Program score [NSQIP]) and markers of sarcopaenia and osteopaenia (temporalis [TMT] and zygoma thickness), against traditional markers (age, World Federation of Neurological Surgery and modified Fisher scale [MFS]) for aSAH outcomes. Univariable and multivariable analysis was then performed for various inpatient and long-term outcomes. RESULTS: TMT was the best performing marker in our cohort with an AUC of 0.82, Somers' D statistic of 0.63 and Tau statistic 0.25. Of the frailty scores, the NSQIP performed the best (AUC 0.69), at levels comparable to traditional markers of aSAH, such as MFS (AUC 0.68). The threshold of 5.5 mm in TMT thickness was found to have a specificity of 0.93, sensitivity of 0.51, positive predictive value of 0.95 and negative predictive value of 0.42. After multivariate analysis, patients with TMT ≥ 5.5 mm (defined as non-frail), were less likely to experience delayed cerebral ischaemia (OR 0.11 [0.01 - 0.93], p = 0.042), any complications (OR 0.20 [0.06 - 0.069], p = 0.011), and had a larger proportion of favourable mRS on discharge (95.0% vs. 58.1%, p = 0.024) and at 3-months (95.0% vs. 64.5%, p = 0.048). However, the gap between unfavourable and favourable mRS was insignificant at the comparison of 1-year outcomes. CONCLUSION: TMT, as a marker of sarcopaenia, correlated well with the presenting status, and outcomes of aSAH. Frailty, as defined by NSQIP, performed at levels equivalent to aSAH scores of clinical relevance, suggesting that, in patients presenting with acute brain injury, both non-neurological and neurological factors were complementary in the determination of eventual clinical outcomes. Further validation of these markers, in addition to exploration of other relevant frailty indices, may help to better prognosticate aSAH outcomes and allow for a precision medicine approach to decision making and optimization of best outcomes.


Assuntos
Fragilidade , Hemorragia Subaracnóidea , Fragilidade/diagnóstico , Fragilidade/epidemiologia , Humanos , Complicações Pós-Operatórias , Valor Preditivo dos Testes , Estudos Retrospectivos , Hemorragia Subaracnóidea/diagnóstico , Hemorragia Subaracnóidea/terapia , Resultado do Tratamento
5.
Open Heart ; 9(1)2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35058344

RESUMO

BACKGROUND: Cardiac arrhythmias have been observed among patients hospitalised with acute COVID-19 infection, and palpitations remain a common symptom among the much larger outpatient population of COVID-19 survivors in the convalescent stage of the disease. OBJECTIVE: To determine arrhythmia prevalence among outpatients after a COVID-19 diagnosis. METHODS: Adults with a positive COVID-19 test and without a history of arrhythmia were prospectively evaluated with 14-day ambulatory electrocardiographic monitoring. Participants were instructed to trigger the monitor for palpitations. RESULTS: A total of 51 individuals (mean age 42±11 years, 65% women) underwent monitoring at a median 75 (IQR 34-126) days after a positive COVID-19 test. Median monitoring duration was 13.2 (IQR 10.5-13.8) days. No participant demonstrated atrial fibrillation, atrial flutter, sustained supraventricular tachycardia (SVT), sustained ventricular tachycardia or infranodal atrioventricular block. Nearly all participants (96%) had an ectopic burden of <1%; one participant had a 2.8% supraventricular ectopic burden and one had a 15.4% ventricular ectopic burden. While 47 (92%) participants triggered their monitor for palpitation symptoms, 78% of these triggers were for either sinus rhythm or sinus tachycardia. CONCLUSIONS: We did not find evidence of malignant or sustained arrhythmias in outpatients after a positive COVID-19 diagnosis. While palpitations were common, symptoms frequently corresponded to sinus rhythm/sinus tachycardia or non-malignant arrhythmias such as isolated ectopy or non-sustained SVT. While these findings cannot exclude the possibility of serious arrhythmias in select individuals, they do not support a strong or widespread proarrhythmic effect of COVID-19 infection after resolution of acute illness.


Assuntos
Arritmias Cardíacas/epidemiologia , COVID-19/diagnóstico , Eletrocardiografia Ambulatorial/métodos , Pandemias , Vigilância da População , SARS-CoV-2 , Adulto , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/etiologia , COVID-19/complicações , COVID-19/virologia , Feminino , Saúde Global , Humanos , Incidência , Masculino , Estudos Prospectivos
6.
Lancet Digit Health ; 4(1): e64-e74, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34772649

RESUMO

Publicly available skin image datasets are increasingly used to develop machine learning algorithms for skin cancer diagnosis. However, the total number of datasets and their respective content is currently unclear. This systematic review aimed to identify and evaluate all publicly available skin image datasets used for skin cancer diagnosis by exploring their characteristics, data access requirements, and associated image metadata. A combined MEDLINE, Google, and Google Dataset search identified 21 open access datasets containing 106 950 skin lesion images, 17 open access atlases, eight regulated access datasets, and three regulated access atlases. Images and accompanying data from open access datasets were evaluated by two independent reviewers. Among the 14 datasets that reported country of origin, most (11 [79%]) originated from Europe, North America, and Oceania exclusively. Most datasets (19 [91%]) contained dermoscopic images or macroscopic photographs only. Clinical information was available regarding age for 81 662 images (76·4%), sex for 82 848 (77·5%), and body site for 79 561 (74·4%). Subject ethnicity data were available for 1415 images (1·3%), and Fitzpatrick skin type data for 2236 (2·1%). There was limited and variable reporting of characteristics and metadata among datasets, with substantial under-representation of darker skin types. This is the first systematic review to characterise publicly available skin image datasets, highlighting limited applicability to real-life clinical settings and restricted population representation, precluding generalisability. Quality standards for characteristics and metadata reporting for skin image datasets are needed.


Assuntos
Conjuntos de Dados como Assunto , Aprendizado de Máquina , Neoplasias Cutâneas/diagnóstico , Dermoscopia , Humanos
7.
Curr Probl Diagn Radiol ; 51(4): 579-588, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34304947

RESUMO

In an era of rapidly expanding knowledge and sub-specialization, it is becoming increasingly common to focus on one organ system. However, the human body is intimately linked, and disease processes affecting one region of the body not uncommonly affect the other organ systems as well. Understanding diseases from a macroscopic perspective, rather than a narrow vantage point, enables efficient and accurate diagnosis. This tenet holds true for diseases affecting both the thoracic and neurologic systems; in isolation, the radiologic appearance of disease in one organ system may be nonspecific, but viewing the pathophysiologic process in both organ systems may markedly narrow the differential considerations, and potentially lead to a definitive diagnosis. In this article, we discuss a variety of disease entities known to affect both the thoracic and neurological systems, either manifesting simultaneously or at different periods of time. Some of these conditions may show neither thoracic nor neurological manifestations. These diseases have been systematically classified into infectious, immune-mediated/ inflammatory, vascular, syndromic/ hereditary and neoplastic disorders. The underlying pathophysiological mechanisms linking both regions and radiologic appearances in both organ systems are discussed. When appropriate, brief clinical and diagnostic information is provided. Ultimately, accurate diagnosis will lead to expedited triage and prompt institution of potentially life-saving treatment for these groups of complex disorders.


Assuntos
Diagnóstico por Imagem , Triagem , Humanos
8.
PLoS One ; 16(6): e0253120, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34138915

RESUMO

BACKGROUND: In the absence of universal testing, effective therapies, or vaccines, identifying risk factors for viral infection, particularly readily modifiable exposures and behaviors, is required to identify effective strategies against viral infection and transmission. METHODS: We conducted a world-wide mobile application-based prospective cohort study available to English speaking adults with a smartphone. We collected self-reported characteristics, exposures, and behaviors, as well as smartphone-based geolocation data. Our main outcome was incident symptoms of viral infection, defined as fevers and chills plus one other symptom previously shown to occur with SARS-CoV-2 infection, determined by daily surveys. FINDINGS: Among 14, 335 participants residing in all 50 US states and 93 different countries followed for a median 21 days (IQR 10-26 days), 424 (3%) developed incident viral symptoms. In pooled multivariable logistic regression models, female biological sex (odds ratio [OR] 1.75, 95% CI 1.39-2.20, p<0.001), anemia (OR 1.45, 95% CI 1.16-1.81, p = 0.001), hypertension (OR 1.35, 95% CI 1.08-1.68, p = 0.007), cigarette smoking in the last 30 days (OR 1.86, 95% CI 1.35-2.55, p<0.001), any viral symptoms among household members 6-12 days prior (OR 2.06, 95% CI 1.67-2.55, p<0.001), and the maximum number of individuals the participant interacted with within 6 feet in the past 6-12 days (OR 1.15, 95% CI 1.06-1.25, p<0.001) were each associated with a higher risk of developing viral symptoms. Conversely, a higher subjective social status (OR 0.87, 95% CI 0.83-0.93, p<0.001), at least weekly exercise (OR 0.57, 95% CI 0.47-0.70, p<0.001), and sanitizing one's phone (OR 0.79, 95% CI 0.63-0.99, p = 0.037) were each associated with a lower risk of developing viral symptoms. INTERPRETATION: While several immutable characteristics were associated with the risk of developing viral symptoms, multiple immediately modifiable exposures and habits that influence risk were also observed, potentially identifying readily accessible strategies to mitigate risk in the COVID-19 era.


Assuntos
COVID-19/prevenção & controle , Febre/diagnóstico , SARS-CoV-2/isolamento & purificação , Autorrelato/estatística & dados numéricos , Adulto , COVID-19/epidemiologia , COVID-19/virologia , Feminino , Febre/epidemiologia , Humanos , Incidência , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Pandemias , Estudos Prospectivos , Fatores de Risco , SARS-CoV-2/fisiologia , Smartphone , Estados Unidos/epidemiologia
9.
JAMA Netw Open ; 3(12): e2030107, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33326027

RESUMO

Importance: The incidence of skin cancer is increasing and evaluation of the utility of total body skin examination (TBSE) in detecting incidental skin cancers is warranted. Objectives: To evaluate the proportion and rate of incidental skin cancer detection in urgent skin cancer clinics and investigate the rate of incidental skin cancer detection in 2 groups based on the degree of clinical suspicion of the index lesion for malignancy. Design, Setting, and Participants: A multicenter retrospective cohort study with a case note review of consecutive secondary care consultations was conducted using data from 2 urgent suspected skin cancer screening clinics in UK National Health Service trusts. The study was performed from January 1, 2015, to March 31, 2016, and data analysis was performed from October 14, 2018, to February 1, 2019. Patients included those presenting with a skin lesion suspicious of malignancy who were referred to the urgent suspected skin cancer clinic (N = 5944) over 15 months. Patients who accepted and received a TBSE were subsequently included in the analysis. Main Outcomes and Measures: The proportion and rate of incidental skin cancer detection through TBSE and whether a clinically suspicious (malignant) index lesion was associated with a higher chance of having a malignant incidental lesion. Results: Of the 5944 patients referred to the clinic, 4726 individuals (79.5%) were evaluated. In the cohort included in the analyses, the median age was 57 years (interquartile range, 39-73 years); 2567 patients (54.3%) were women. A total of 1117 skin cancers were identified; of these, 242 lesions (21.7%) were detected incidentally through TBSE, including 197 of 570 (34.6%) basal cell carcinomas, 16 of 250 (6.4%) squamous cell carcinomas, and 25 of 215 (11.6%) melanomas. The detection rate of incidental malignant lesions was 5.1 lesions per 100 patients examined (5.1%; 95% CI, 4.5%-5.8%). There was a higher detection rate of histologically confirmed incidental malignant lesions in individuals with clinically suspicious index lesions requiring biopsy (10.9%; 95% CI, 9.5%-12.5%) compared with those presenting with clinically benign index lesions (2.0%; 95% CI, 1.6%-2.5%) (P < .001). Conclusions and Relevance: The findings of this study support the use of TBSE for urgent skin cancer referrals, highlighting the potential harms of solitary lesion assessment in a subgroup. Individuals presenting with a clinically suspicious index lesion requiring biopsy are most likely to benefit from TBSE and should be counseled regarding the benefit.


Assuntos
Carcinoma Basocelular/patologia , Carcinoma de Células Escamosas/patologia , Melanoma/patologia , Encaminhamento e Consulta/estatística & dados numéricos , Neoplasias Cutâneas , Biópsia/métodos , Biópsia/estatística & dados numéricos , Dermatologia/métodos , Detecção Precoce de Câncer , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Exame Físico/métodos , Exame Físico/estatística & dados numéricos , Estudos Retrospectivos , Pele/patologia , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/epidemiologia , Neoplasias Cutâneas/patologia , Reino Unido
10.
BMJ Case Rep ; 12(11)2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31712244

RESUMO

Panspinal epidural abscesses are an extremely rare yet potentially fatal condition. Whether cases are best managed surgically or medically is currently controversial. A 63-year-old patient with diabetes presented initially with abdominal pain, back pain, urinary retention and constipation. He subsequently developed fevers, radicular pain and new-onset weakness in the right leg. MRI confirmed a panspinal epidural abscess extending from C7 to L5, with group B Streptococcus (GBS) cultured on sampling. Due to the significant risks of surgery he was managed conservatively, initially with ceftriaxone, and subsequently in combination with linezolid. Repeat MRI 3 months after presentation revealed complete resolution of the abscess. This case illustrates how conservative management is a valid option for patients with this condition, and supports the use of synergistic linezolid in this scenario. It also highlights how some cases may not initially present with the classically described triad of fever, back pain and loss of neurological function.


Assuntos
Antibacterianos/uso terapêutico , Ceftriaxona/uso terapêutico , Abscesso Epidural/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Linezolida/uso terapêutico , Diabetes Mellitus Tipo 2/complicações , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
11.
Angew Chem Int Ed Engl ; 58(48): 17236-17240, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31507030

RESUMO

Materials for high-efficiency photocatalytic CO2 reduction are desirable for solar-to-carbon fuel conversion. Herein, highly dispersed nickel cobalt oxyphosphide nanoparticles (NiCoOP NPs) were confined in multichannel hollow carbon fibers (MHCFs) to construct the NiCoOP-NPs@MHCFs catalysts for efficient CO2 photoreduction. The synthesis involves electrospinning, phosphidation, and carbonization steps and permits facile tuning of chemical composition. In the catalyst, the mixed metal oxyphosphide NPs with ultrasmall size and high dispersion offer abundant catalytically active sites for redox reactions. At the same time, the multichannel hollow carbon matrix with high conductivity and open ends will effectively promote mass/charge transfer, improve CO2 adsorption, and prevent the metal oxyphosphide NPs from aggregation. The optimized hetero-metal oxyphosphide catalyst exhibits considerable activity for photosensitized CO2 reduction, affording a high CO evolution rate of 16.6 µmol h-1 (per 0.1 mg of catalyst).

12.
J Endourol Case Rep ; 5(3): 113-116, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32775641

RESUMO

Background: Filariasis is a tropical disease caused by infection with nematode parasites of the Filarioidea family. Filariasis is an endemic disease in parts of India, Sub-Saharan Africa, and Southeast Asia. Filariasis is a progressive disease predominantly affecting the lymphoreticular system, which can result in genitourinary complications (hydrocele, scrotal pain, and infertility), lymphedema, and elephantitis. Retroperitoneal fibrosis has a broad etiology, including secondary to chronic infection. Currently an estimated 25 million men are suffering from lymphatic filariasis with urogenital involvement worldwide. Case Presentation: We present a rare case of a 40-year-old man presenting with fever, groin lymphadenopathy, and a history of infertility. Imaging confirmed significant hydronephrosis and retroperitoneal fibrosis. Filariasis serology was positive. Prior bilateral testicular biopsy demonstrated chronic inflammation and atrophy. Disease course was not improved by empirical eradication and supportive retrograde ureteral stenting. The patient developed elephantitis and progressive retroperitoneal fibrosis leading to a solitary functioning right kidney with nephrostomy. Conclusion: Urologists should be aware of index presentations of filariasis and its associated urological complications, particularly in the travelling adult population in whom the etiology of renal impairment and infertility remains unclear.

13.
Adv Mater ; 31(7): e1806552, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30575143

RESUMO

Altering a material's catalytic properties would require identifying structural features that deliver electrochemically active surfaces. Single-crystalline porous materials, combining the advantages of long-range ordering of bulk crystals and large surface areas of porous materials, would create sufficient active surfaces by stabilizing 2D active moieties confined in lattice and may provide an alternative way to create high-energy surfaces for electrocatalysis that are kinetically trapped. Here, a radical concept of building active metal-nitrogen moieties with unsaturated nitrogen coordination on a porous surface by directly growing metallic porous metal nitride (Fe3 N and Ta5 N6 ) single crystals at unprecedented 2 cm scale is reported. These porous single crystals demonstrate exceptionally high conductivity of 0.1-1.0 × 105 S cm-1 , while the atomic surface layers of the porous crystals are confirmed to be an Fe termination layer for Fe3 N and a Ta termination layer for Ta5 N6 . The unsaturated metal-nitrogen moieties (Fe6 -N and Ta5 -N3 ) with unique electronic structures demonstrate enhanced electrocatalysis performance and durability.

14.
Clin J Gastroenterol ; 11(6): 470-475, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30145768

RESUMO

A 62-year-old female patient diagnosed with oesophageal adenocarcinoma underwent radical treatment consisting of neoadjuvant chemotherapy and oesophagectomy with no major complications. Eleven months later, she re-presented with a mass at one of the chest drain sites. A PET-CT scan and biopsy demonstrated this to be a single recurrence of the oesophageal adenocarcinoma. Excision of the metastatic lesion was considered as per metachronous single site metastasis. However, the operation was postponed due to acute kidney injury. Restaging after 6 weeks revealed progressive metastatic disease. The patient underwent palliative therapy and passed away soon after. Oesophageal cancer recurrence has a very poor prognosis, and factors such as the disease-free interval, site of recurrence and tumour pathological factors must be considered when stratifying for suitability for metastasectomy. A period of watchful waiting followed by restaging is essential to rule out patients with indolent metastatic disease.


Assuntos
Adenocarcinoma/patologia , Neoplasias Esofágicas/patologia , Segunda Neoplasia Primária/secundário , Neoplasias Torácicas/secundário , Parede Torácica/patologia , Adenocarcinoma/terapia , Biópsia , Drenagem , Neoplasias Esofágicas/terapia , Esofagectomia , Feminino , Humanos , Pessoa de Meia-Idade , Terapia Neoadjuvante , Segunda Neoplasia Primária/diagnóstico por imagem , Segunda Neoplasia Primária/terapia , Cuidados Paliativos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias Torácicas/diagnóstico por imagem , Neoplasias Torácicas/terapia , Parede Torácica/diagnóstico por imagem
15.
Angew Chem Int Ed Engl ; 57(34): 10944-10948, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-29949224

RESUMO

We have designed and synthesized novel hollow Ni/Fe layered double hydroxide (LDH) polyhedrons as an advanced sulfur host for enhancing the performance of lithium-sulfur (Li-S) batteries. The Ni/Fe LDH host shows multiple advantages. First, the Ni/Fe LDH shells can provide sufficient sulfiphilic sites for chemically bonding with polysulfides. Second, the hollow architecture can provide sufficient inner space for both loading a large amount of sulfur and accommodating its large volumetric expansion. Moreover, once the active material is confined within the host, the shells could easily restrict the outward diffusion of polysulfides, guaranteeing prolonged cycle life even with high sulfur loading. As a result, the S@Ni/Fe LDH cathode has successfully solved the main issues related to sulfur electrodes, and it exhibits significantly improved electrochemical performances with prolonged life over 1000 cycles and excellent rate properties.

16.
Angew Chem Int Ed Engl ; 57(31): 9859-9863, 2018 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-29923279

RESUMO

Antimony-based electrode materials with high specific capacity have aroused considerable interest as anode materials for sodium-ion batteries (SIBs). Herein, we develop a template-engaged ion-exchange method to synthesize Sb2 Se3 microclips, and the as-obtained Sb2 Se3 microclips are further in situ coated with polypyrrole (PPy). Benefiting from the structural and compositional merits, these PPy-coated Sb2 Se3 microclips exhibit enhanced sodium-storage properties in terms of high reversible capacity, superior rate capability, and stable cycling performance.

17.
Angew Chem Int Ed Engl ; 56(14): 3897-3900, 2017 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-28244625

RESUMO

Hollow nanostructures have attracted increasing research interest in electrochemical energy storage and conversion owing to their unique structural features. However, the synthesis of hollow nanostructured metal phosphides, especially nonspherical hollow nanostructures, is rarely reported. Herein, we develop a metal-organic framework (MOF)-based strategy to synthesize carbon incorporated Ni-Co mixed metal phosphide nanoboxes (denoted as NiCoP/C). The oxygen evolution reaction (OER) is selected as a demonstration to investigate the electrochemical performance of the NiCoP/C nanoboxes. For comparison, Ni-Co layered double hydroxide (Ni-Co LDH) and Ni-Co mixed metal phosphide (denoted as NiCoP) nanoboxes have also been synthesized. Benefiting from their structural and compositional merits, the as-synthesized NiCoP/C nanoboxes exhibit excellent electrocatalytic activity and long-term stability for OER.

18.
Nat Commun ; 6: 6694, 2015 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-25798849

RESUMO

While the synthesis of hollow structures of transition metal oxides is well established, it is extremely challenging to fabricate complex hollow structures for mixed transition metal sulfides. Here we report an anion exchange method to synthesize a complex ternary metal sulfides hollow structure, namely nickel cobalt sulfide ball-in-ball hollow spheres. Uniform nickel cobalt glycerate solid spheres are first synthesized as the precursor and subsequently chemically transformed into nickel cobalt sulfide ball-in-ball hollow spheres. When used as electrode materials for electrochemical capacitors, these nickel cobalt sulfide hollow spheres deliver a specific capacitance of 1,036 F g(-1) at a current density of 1.0 A g(-1). An asymmetric supercapacitor based on these ball-in-ball structures shows long-term cycling performance with a high energy density of 42.3 Wh kg(-1) at a power density of 476 W kg(-1), suggesting their potential application in high-performance electrochemical capacitors.

19.
Angew Chem Int Ed Engl ; 54(18): 5331-5, 2015 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-25702684

RESUMO

Nanoframe-like hollow structures with unique three-dimensional (3D) open architecture hold great promise for various applications. Current research efforts mainly focus on frame-like noble metals and metal oxides. However, metal sulfides with frame-like nanostructures have been rarely reported. Starting from metal-organic frameworks (MOFs), we demonstrate a novel structure-induced anisotropic chemical etching/anion exchange method to transform Ni-Co Prussian blue analogue (PBA) nanocubes into NiS nanoframes with tunable size. The reaction between Ni-Co PBA nanocube templates and Na2 S in solution leads to the formation of well-defined NiS nanoframes. The different reactivity between the edges and the plane surface of the Ni-Co PBA nanocubes is found to be the key factor for the formation of NiS nanoframes. Benefitting from their structural merits including 3D open structure, small size of primary nanoparticles, high specific surface area, and good structural robustness, the as-derived NiS nanoframes manifest excellent electrochemical performance for electrochemical capacitors and hydrogen evolution reaction in alkaline electrolyte.

20.
Small ; 8(22): 3432-7, 2012 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-22941974

RESUMO

Ultra-light Ni nanofoams composed of nanowires have been synthesized on a large scale by a facile reflux approach. From the Ni nanofoam, many other functional nanofoams, composed of semi-hollow NiO nanowires, multi-generation Ni nanowires, and noble metal nanotubes, can be easily derived for many important applications. As an example, the promising application of the NiO nanofoam in lithium-ion batteries is demonstrated.

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