Transition‐metal phosphides (TMPs) have emerged as promising catalyst candidates for the hydrogen evolution reaction (HER). Although numerous methods have been investigated to obtain TMPs, most rely ...on traditional synthetic methods that produce materials that are inherently deficient with respect to electrical conductivity. An electrospinning‐based reduction approach is presented, which generates nickel phosphide nanoparticles in N‐doped porous carbon nanofibers (Ni2P@NPCNFs) in situ. Ni2P nanoparticles are protected from irreversible fusion and aggregation in subsequent high‐temperature pyrolysis. The resistivity of Ni2P@NPCNFs (5.34 Ω cm) is greatly decreased by 104 times compared to Ni2P (>104 Ω cm) because N‐doped carbon NFs are incorporated. As an electrocatalyst for HER, Ni2P@NPCNFs reveal remarkable performance compared to other previously reported catalysts in acidic media. Additionally, it offers excellent catalytic ability and durability in both neutral and basic media. Encouraged by the excellent electrocatalytic performance of Ni2P@NPCNFs, a series of pea‐like MxP@NPCNFs, including Fe2P@NPCNFs, Co2P@NPCNFs, and Cu3P@NPCNFs, were synthesized by the same method. Detailed characterization suggests that the newly developed method could render combinations of ultrafine metal phosphides with porous carbon accessible; thereby, extending opportunities in electrocatalytic applications.
Like peas in a pod: An electrospinning‐based reduction approach was used to embed metal phosphide nanoparticles in nitrogen‐doped porous carbon nanofibers (NPCNFs). A series of pea‐like MxP@NPCNFs structures were fabricated (MxP=Ni2P, Fe2P, Co2P, and Cu3P). Ni2P@NPCNFs is a highly active catalyst for the hydrogen evolution reaction at all pH values.
Aim
The purpose of this study was to develop and validate an individualized nomogram to predict venous thromboembolism (VTE) risk in hospitalized postoperative breast cancer patients.
Design
A ...single‐central retrospective and non‐interventional trial.
Methods
For model development, we used data from 4,755 breast cancer patients between 1 November 2016–30 June 2018 (3,310 patients in the development group and 1,445 in the validation group). Overall, 216 patients developed VTE (150 in development group and 66 in validation group). The model was validated by receiver operating characteristic curves and the calibration plot. The clinical utility of the model was determined through decision curve analysis.
Results
The individualized nomogram consisted of six clinical factors: age, body mass index, number of cardiovascular comorbidities, neoadjuvant chemotherapy, surgical treatment, hospital length of stay and two pre‐operative biomarkers of Homocysteine and D‐dimer. The model at the 3.9% optimal cut‐off had the area under the curve of 0.854 (95% CI, 0.824–0.884) and 0.805 (95% CI, 0.740–0.870) in the development and validation groups. A p = 0.570 of the calibration test showed that the model was well‐calibrated. The net benefit of the model was better between threshold probabilities of 5%–30% in decision curve analysis.
Conclusion
The nomogram of VTE risk assessment, is applicable to hospitalized postoperative breast cancer patients. However, multi‐central prospective studies are needed to improve and validate the model. Effectiveness and safety of thromboprophylaxis in high‐risk patients are needed to demonstrate in interventional trials.
Impact
This nomogram can be used in clinical to inform practice of physicians and nurses to predict the VTE probability and maybe direct personalized decision making for thromboprophylaxis in hospitalized postoperative breast cancer patients.
摘要
目标
本研究的目的是开发和验证个体化列线图,以预测乳腺癌术后住院患者静脉血栓栓塞(VTE)的风险。
设计
单中心回顾性非干预试验。
方法
对于模型开发,我们使用了2016年11月1日至2018年6月30日期间4755名乳腺癌患者的数据(发生组3310名,验证组1445名)。总体来说,216例患者发生了静脉血栓栓塞(发生组150例,验证组66例)。通过接收者工作特性曲线和标定曲线对模型进行验证。通过决策曲线分析确定模型的临床实用性。
结果
个体化列线图由6个临床因素组成:年龄、体重指数、心血管共病数量、新辅助化疗、手术治疗、住院时间以及术前同型半胱氨酸和D‐二聚体两个生物标志物。在开发组和验证组中,3.9%最优截止点的模型下面积为0.854(95%可信区间,0.824‐0.884)和0.805(95%可信区间,0.740‐0.870)。校准试验的p = 0.570 表明模型校准良好。在决策曲线分析中,阈值概率在5%‐30%之间,模型的净效益较好。
结论
静脉血栓栓塞风险评估列线图适用于乳腺癌术后住院患者。然而,需要多中心前瞻性研究来改进和验证该模型。高危患者血栓预防的有效性和安全性需要在干预试验中证明。
影响
该列线图可用于临床指导医生和护士预测静脉血栓栓塞发生率,并可指导乳腺癌术后住院患者血栓预防的个性化决策。
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Recently metal-organic frameworks (MOFs) have attracted more attention in developing new electrochemical sensors due to their unique properties such as crystalline ordered structures, ...tunable pore sizes, large surface areas, chemical tenability and thermal stability. However, the direct application of single component MOFs in electrochemistry is limited owing to their poor electronic conductivity and inferior electrocatalytic ability. Herein, Ni(II)-Based metal-organic framework (Ni(II)-MOFs) was successfully anchored on carbon nanotubes (CNTs) by in situ solvothermal method for the first time. In the as-prepared composites, 2∼3nm MOFs nanoparticles homogeneously dispersed on conducting CNTs allowed for the MOFs nanoparticles to be wired up to a current collector through the underlying conducting CNTs. As the electrode materials of an non-enzymatic H2O2 biosensor, the Ni(II)-MOFs/CNTs exhibited excellent electrocatalytic performance including a wide linear detection range from 0.01 to 51.6mmolL−1, low detection limit of 2.1μmolL−1 and very fast response of 2.5s for H2O2 sensing. Most importantly, the stability and conductivity of Ni(II)-based MOFs is far higher than that of pure MOFs.
In this work, we reported a novel and slack rose-like metal organic precursor designed by coordinating p-phenylenediamine with cobalt ion. After subsequent pyrolysis and acid etching process, the ...as-prepared Co-N-C catalyst delivered a superior catalytic activity and long-term durability. Further applied in the Zn-air battery, it also displayed a comparable performance with 20% Pt/C.
Engineering the microstructure at the atomic scale is paramount to developing effective catalysts due to the active sites and mass/charge transfer ability of catalysts severely limited by their ...microstructure. Herein, we nanoengineer unique necklace-like nanochains composed of molybdenum nitride embedded N-doped carbon, in which the series-wound nanochains are built from hollow beads with a very thin porous wall. MoN nanodots were downsized to 3 nm and uniformly embedded in hollow N-doped porous carbon pearls and wires. The unique hierarchical hollow cavity and ultrathin wall structure of the nanochains offer a high effective reaction chamber, more active sites, and mass/charge transfer for remarkably fast HER. The resultant MoN@NPCNCs exhibit an extremely low HER overpotential of 72 mV at 10 mA cm −2 , a low Tafel slope of 53.21 mV dec −1 in an acidic solution, which is far lower than those of MoN embedded N-doped carbon nanofibers (MoN@NPCNFs, 139.21 mV vs. RHE/82.69 mV dec −1 ), and other previously reported MoN based catalysts. Density functional theory (DFT) calculations reveal that MoN and N-doped carbon synergistically optimizes the free energy of hydrogen adsorption on the active sites. Furthermore, this catalyst also offers an excellent electrocatalytic ability and durability in both neutral and alkaline media.
One-dimensional Pd–Au nanowires (Pd–Au NWs) were prepared and applied to fabricate an electrochemiluminescence (ECL) biosensor for the detection of acetylcholinesterase (AChE) activity. Compared with ...single-component of Pd or Au, the bimetallic nanocomposite of Pd–Au NWs offers a larger surface area for the immobilization of enzyme, and displays superior electrocatalytic activity and efficient electron transport capacity. In the presence of AChE and choline oxidase (ChOx), acetylcholine (ATCl) is hydrolyzed by AChE to generate thiocholine, then thiocholine is catalyzed by ChOx to produce H2O2in situ, which serves as the coreactant to effectively enhance the ECL intensity in luminol-ECL system. The detection principle is based on the inhibited AChE and reactivated AChE as dual biomarkers, in which AChE was inhibited by organophosphorus (OP) agents, and then reactivated by obidoxime. Such dual biomarkers method can achieve credible evaluation for AChE activity via providing AChE activity before and after reactivation. The liner range for AChE activity detection was from 0.025UL−1 to 25KUL−1 with a low detection limit down to 0.0083UL−1.
•One-dimensional Pd–Au NWs were synthesized.•An ECL biosensor was fabricated for AChE detection based on dual biomarkers for the first time.•The method of dual biomarkers can achieve credible and accurate evaluation for AChE activity.•Pd–Au NWs and AChE–ChOx remarkably amplify the ECL response.
Porous ZnO nanosheets have been successfully synthesized through a one-pot wet-chemical method followed by an annealing treatment. The as-prepared products were characterized by X-ray diffraction ...(XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) theory. The results indicate that the porous ZnO nanosheets with a length of a few micrometers were full of mesopores. The porous ZnO nanosheets combining the advantages of having porous structures, being single-crystalline, and being ultra-thin present a pretty good sensing performance and a dramatic response speed in ethylene detection. The response and recovery times are 8 s and 20 s, respectively, which are the rapidest response and recovery speeds in ethylene sensors to our knowledge. The sensing mechanism has also been discussed. Furthermore, the porous ZnO nanosheets are employed to determine fruit ripeness by using bananas as an example. It can be found that the porous ZnO nanosheets present different responses to bananas at different maturity stages. It is expected that the porous ZnO nanosheets may provide a new pathway to develop advanced nanomaterials for practical application in ethylene monitoring during the fruit ripening process.
Porous ZnO nanosheets exhibit superior sensitivity in ethylene detection and present different intensity responses to bananas at different maturity stages.
Since the oxygen evolution catalysis process is vital yet arduous in energy conversion and storage devices, it is highly desirous but extremely challenging to engineer earth-abundant, ...noble-metal-free nanomaterials with superior electrocatalytic activity toward effective oxygen evolution reactions (OERs). Herein, we construct a prismlike cobalt–iron layered double hydroxide (Co–Fe LDH) with a Co/Fe ratio of 3:1 utilizing a facile self-templated strategy. Instead of carbon-species-coupled treatment, we focus on ameliorating the intrinsic properties of LDHs as OER electrocatalysts accompanied by the hierarchical nanoflake shell, well-defined interior cavity, and numerous microporous defects. In contrary to conventional LDHs synthesized via a one-pot method, Co–Fe LDHs fabricated in this work possess a huge specific surface area up to 294.1 m2 g–1, which not only provides abundant active sites but also expedites the kinetics of the OER process. The as-prepared Co–Fe LDH electrocatalysts exhibit advanced electrocatalytic performance and a dramatic stability of the OER in an alkaline environment. In particular, the contribution of micropore defects is clearly discussed according to the electrochemical impedance spectroscopy analysis, in which the time constant of the OER at the micropore defect is several orders of magnitude smaller than that at the exterior of Co–Fe LDHs, forcefully verifying the intrinsic catalytic activity enhancement derived from the micropore defects. This work provides a promising model to improve OER electrocatalyst activity via produce defects and research the contribution of micropore defects.
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