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1.
Proc Natl Acad Sci U S A ; 120(15): e2220608120, 2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-37018199

RESUMO

A precise modulation of heterogeneous catalysts in structural and surface properties promises the development of more sustainable advanced oxidation water purification technologies. However, while catalysts with superior decontamination activity and selectivity are already achievable, maintaining a long-term service life of such materials remains challenging. Here, we propose a crystallinity engineering strategy to break the activity-stability tradeoff of metal oxides in Fenton-like catalysis. The amorphous/crystalline cobalt-manganese spinel oxide (A/C-CoMnOx) provided highly active, hydroxyl group-rich surface, with moderate peroxymonosulfate (PMS)-binding affinity and charge transfer energy and strong pollutant adsorption, to trigger concerted radical and nonradical reactions for efficient pollutant mineralization, thereby alleviating the catalyst passivation by oxidation intermediate accumulation. Meanwhile, the surface-confined reactions, benefited from the enhanced adsorption of pollutants at A/C interface, rendered the A/C-CoMnOx/PMS system ultrahigh PMS utilization efficiency (82.2%) and unprecedented decontamination activity (rate constant of 1.48 min-1) surpassing almost all the state-of-the-art heterogeneous Fenton-like catalysts. The superior cyclic stability and environmental robustness of the system for real water treatment was also demonstrated. Our work unveils a critical role of material crystallinity in modulating the Fenton-like catalytic activity and pathways of metal oxides, which fundamentally improves our understanding of the structure-activity-selectivity relationships of heterogeneous catalysts and may inspire material design for more sustainable water purification application and beyond.

2.
Nano Lett ; 24(17): 5324-5331, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38624236

RESUMO

Phase transformation offers an alternative strategy for the synthesis of nanomaterials with unconventional phases, allowing us to further explore their unique properties and promising applications. Herein, we first observed the amorphization of Pt nanoparticles on the RuO2 surface by in situ scanning transmission electron microscopy. Density functional theory calculations demonstrate the low energy barrier and thermodynamic driving force for Pt atoms transferring from the Pt cluster to the RuO2 surface to form amorphous Pt. Remarkably, the as-synthesized amorphous Pt/RuO2 exhibits 14.2 times enhanced mass activity compared to commercial RuO2 catalysts for the oxygen evolution reaction (OER). Water electrolyzer with amorphous Pt/RuO2 achieves 1.0 A cm-2 at 1.70 V and remains stable at 200 mA cm-2 for over 80 h. The amorphous Pt layer not only optimized the *O binding but also enhanced the antioxidation ability of amorphous Pt/RuO2, thereby boosting the activity and stability for the OER.

3.
J Am Chem Soc ; 146(12): 8464-8471, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38483268

RESUMO

One-dimensional (1D) high-entropy compounds (HECs) with subnano diameters are highly attractive because long-range electron delocalization may occur along the high-entropy atomic chain, which results in extraordinary properties. Nevertheless, synthesizing such 1D HECs presents a substantial challenge, and the physicochemical attributes of these novel structures remain ambiguous. Herein, we developed a comelting-filling-freezing-modification (co-MFFM) method for synthesizing 1D high-entropy metal phosphide (HEP) by simultaneously encapsulating various metal cations within single-walled carbon nanotubes (SWCNTs) followed with a phosphorization process. The resulting 1D HEP nanowires confined within SWCNTs exhibit crucial features, including an ultrafine, high-entropy, and amorphous structure, along with a core-shell arrangement. The SWCNT as a shell could donate π electrons to 1D HEP for enhanced electron delocalization and protect 1D HEP as an atomically single-layered protective covering, thus boosting high electrocatalytic activity and stability. Moreover, the co-MFFM method demonstrates scalability for mass production and displays universal applicability to the synthesis of various 1D HECs.

4.
Small ; : e2401162, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38511537

RESUMO

Constructing the pore structures in amorphous metal oxide nanosheets can enhance their electrocatalytic performance by efficiently increasing specific surface areas and facilitating mass transport in electrocatalysis. However, the accurate synthesis for porous amorphous metal oxide nanosheets remains a challenge. Herein, a facile nitrate-assisted oxidation strategy is reported for synthesizing amorphous mesoporous iridium oxide nanomeshes (a-m IrOx NMs) with a pore size of ∼4 nm. X-ray absorption characterizations indicate that a-m IrOx NMs possess stretched Ir─O bonds and weaker Ir-O interaction compared with commercial IrO2. Combining thermogravimetric-fourier transform infrared spectroscopy with differential scanning calorimetry measurements, it is demonstrated that sodium nitrate, acting as an oxidizing agent, is conducive to the formation of amorphous nanosheets, while the NO2 produced by the in situ decomposition of nitrates facilitates the generation of pores within the nanomeshes. As an anode electrocatalyst in proton exchange membrane water electrolyzer, a-m IrOx NMs exhibit superior performance, maintaining a cell voltage of 1.67 V at 1 A cm-2 for 120 h without obvious decay with a low loading (0.4 mgcatalyst cm-2). Furthermore, the nitrate-assisted method is demonstrated to be a general approach to prepare various amorphous metal oxide nanomeshes, including amorphous RhOx, TiOx, ZrOx, AlOx, and HfOx nanomeshes.

5.
Nano Lett ; 23(21): 10004-10012, 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37877790

RESUMO

Cation exchange (CE) in metal oxides under mild conditions remains an imperative yet challenging goal to tailor their composition and enable practical applications. Herein, we first develop an amorphization-induced strategy to achieve room-temperature CE for universally synthesizing single-atom doped In2O3 nanosheets (NSs). Density functional theory (DFT) calculations elucidate that the abundant coordination-unsaturated sites present in a-In2O3 NSs are instrumental in surmounting the energy barriers of CE reactions. Empirically, a-In2O3 NSs as the host materials successfully undergo exchange with unary cations (Cu2+, Co2+, Mn2+, Ni2+), binary cations (Co2+Mn2+, Co2+Ni2+, Mn2+Ni2+), and ternary cations (Co2+Mn2+Ni2+). Impressively, high-loading single-atom doped (over 10 atom %) In2O3 NSs were obtained. Additionally, Cu/a-In2O3 NSs exhibit an excellent ethanol yield (798.7 µmol g-1 h-1) with a high selectivity of 99.5% for the CO2 photoreduction. This work offers a new approach to induce CE reactions in metal oxides under mild conditions and constructs scalable single-atom doped catalysts for critical applications.

6.
Pak J Med Sci ; 40(4): 690-694, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38544998

RESUMO

Objective: To compare the clinical efficacy of microendoscopic discectomy + fibrous ring suture versus microendoscopic discectomy alone in the treatment of lumbar disc herniation (LDH) in young and middle-aged patients. Methods: A retrospective analysis was performed on the clinical data of 66 young and middle-aged patients with single-segment LDH diagnosed in Orthopedic Hospital of Henan Province from October 2019 to October 2022. All patients were divided into two groups: the microendoscopic discectomy + fibrous ring suture group and the microendoscopic discectomy alone group, with 33 cases in each group. The Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI) scores of the two groups were recorded before surgery and six and twelve months after surgery. Results: Both groups completed the surgery and postoperative follow-up successfully and showed no statistically significant differences in terms of incision length, duration of surgery, intraoperative blood loss and length of hospital stay (all P>0.05). VAS, ODI and JOA scores were significantly improved in both groups at 6 and 12 months after surgery compared with those before surgery (all P<0.05). The two groups were similar in terms of excellent and good rates of postoperative modified MacNab Evaluation Criteria, with no statistically significant differences. No serious complications were observed in the two groups during and after surgery. Conclusion: Both of the two surgical methods are effective in the treatment of LDH in young and middle-aged patients, and microendoscopic discectomy + fibrous ring suture in particular may be preferred because it results in significant improvement in patients' VAS and ODI scores.

7.
J Am Chem Soc ; 145(22): 12148-12154, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37224478

RESUMO

Spiral two-dimensional (2D) nanosheets exhibit unique physical and chemical phenomena due to their twisted structures. While self-assembly of clusters is an ideal strategy to form hierarchical 2D structures, it is challenging to form spiral nanosheets. Herein, we first report a screw dislocation involved assembled method to obtain 2D spiral cluster assembled nanosheets (CANs) with uniform square morphology. The 2D spiral Ru CANs with a length of approximately 4 µm and thickness of 20.7 ± 3.0 nm per layer were prepared via the assembly of 1-2 nm Ru clusters in the presence of molten block copolymer Pluronic F127. Cryo-electron microscopy (cryo-EM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) demonstrate the existence of screw dislocation in the spiral assembled structure. The X-ray absorption fine structure spectrum indicates that Ru clusters are Ru3+ species, and Ru atoms are mainly coordinated with Cl with a coordination number of 6.5. Fourier-transform infrared (FT-IR) spectra and solid-state nuclear magnetic resonance hydrogen spectra (1H NMR) indicate that the assembly process of Ru clusters is formed by noncovalent interactions, including hydrogen bonding and hydrophilic interactions. Additionally, the Ru-F127 CANs exhibit excellent photothermal conversion performance in the near-infrared (NIR) region.

8.
Small ; 19(43): e2303360, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37381653

RESUMO

Transition metal oxides with high theoretical capacities are promising anode materials for lithium-ion batteries (LIBs). However, the sluggish reaction kinetics remain a bottleneck for fast-charging applications due to its slow Li+ migration rate. Herein, a strategy is reported of significantly reducing the Li+ diffusion barrier of amorphous vanadium oxide by constructing a specific ratio of the VO local polyhedron configuration in amorphous nanosheets. The optimized amorphous vanadium oxide nanosheets with a ratio ≈1:4 for octahedron sites (Oh ) to pyramidal sites (C4v ) revealed by Raman spectroscopy and X-ray absorption spectroscopy (XAS) demonstrate the highest rate capability (356.7 mA h g-1 at 10.0 A g-1 ) and long-term cycling life (455.6 mA h g-1 at 2.0 A g-1 over 1200 cycles). Density functional theory (DFT)calculations further verify that the local structure (Oh :C4v = 1:4) intrinsically changes the degree of orbital hybridization between V and O atoms and contributes to a higher intensity of electron occupied states near the Fermi level, thus resulting in a low Li+ diffusion barrier for favorable Li+ transport kinetics. Moreover, the amorphous vanadium oxide nanosheets possess a reversible VO vibration mode and volume expansion rate close to 0.3%, as determined through in situ Raman and in situ transmission electron microscopy.

9.
Eur Radiol ; 33(10): 6993-7002, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37148353

RESUMO

OBJECTIVE: To evaluate the ability of diffusion-relaxation correlation spectrum imaging (DR-CSI) to predict the consistency and extent of resection (EOR) of pituitary adenomas (PAs). METHODS: Forty-four patients with PAs were prospectively enrolled. Tumor consistency was evaluated at surgery as either soft or hard, followed by histological assessment. In vivo DR-CSI was performed and spectra were segmented following to a peak-based strategy into four compartments, designated A (low ADC), B (mediate ADC, short T2), C (mediate ADC, long T2), and D (high ADC). The corresponding volume fractions ([Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]) along with the ADC and T2 values were calculated and assessed using univariable analysis for discrimination between hard and soft PAs. Predictors of EOR > 95% were analyzed using logistic regression model and receiver-operating-characteristic analysis. RESULTS: Tumor consistency was classified as soft (n = 28) or hard (n = 16). Hard PAs presented higher [Formula: see text] (p = 0.001) and lower [Formula: see text] (p = 0.013) than soft PAs, while no significant difference was found in other parameters. [Formula: see text] significantly correlated with the level of collagen content (r = 0.448, p = 0.002). Knosp grade (odds ratio [OR], 0.299; 95% confidence interval [CI], 0.124-0.716; p = 0.007) and [Formula: see text] (OR, 0.834, per 1% increase; 95% CI, 0.731-0.951; p = 0.007) were independently associated with EOR > 95%. A prediction model based on these variables yielded an AUC of 0.934 (sensitivity, 90.9%; specificity, 90.9%), outperforming the Knosp grade alone (AUC, 0.785; p < 0.05). CONCLUSION: DR-CSI may serve as a promising tool to predict the consistency and EOR of PAs. CLINICAL RELEVANCE STATEMENT: DR-CSI provides an imaging dimension for characterizing tissue microstructure of PAs and may serve as a promising tool to predict the tumor consistency and extent of resection in patients with PAs. KEY POINTS: • DR-CSI provides an imaging dimension for characterizing tissue microstructure of PAs by visualizing the volume fraction and corresponding spatial distribution of four compartments ([Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]). • [Formula: see text] correlated with the level of collagen content and may be the best DR-CSI parameter for discrimination between hard and soft PAs. • The combination of Knosp grade and [Formula: see text] achieved an AUC of 0.934 for predicting the total or near-total resection, outperforming the Knosp grade alone (AUC, 0.785).


Assuntos
Adenoma , Neoplasias Hipofisárias , Humanos , Neoplasias Hipofisárias/diagnóstico por imagem , Neoplasias Hipofisárias/cirurgia , Neoplasias Hipofisárias/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Curva ROC , Adenoma/diagnóstico por imagem , Adenoma/cirurgia , Adenoma/patologia
10.
Acta Radiol ; 64(9): 2552-2560, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37331987

RESUMO

BACKGROUND: Non-invasive detection of isocitrate dehydrogenase (IDH) mutational status in gliomas is clinically meaningful for molecular stratification of glioma; however, it remains challenging. PURPOSE: To investigate the usefulness of texture analysis (TA) of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and histogram analysis of diffusion kurtosis imaging (DKI) maps for evaluating IDH mutational status in gliomas. MATERIAL AND METHODS: This retrospective study enrolled 84 patients with histologically confirmed gliomas, comprising IDH-mutant (n = 34) and IDH-wildtype (n = 50). TA was performed for the quantitative parameters derived by DCE-MRI. Histogram analysis was performed for the quantitative parameters derived by DKI. Unpaired Student's t-test was used to identify IDH-mutant and IDH-wildtype gliomas. Logistic regression and receiver operating characteristic (ROC) curve analyses were used to compare the diagnostic performance of each parameter and their combination for predicting the IDH mutational status in gliomas. RESULTS: Significant statistical differences in the TA of DCE-MRI and histogram analysis of DKI were observed between IDH-mutant and IDH-wildtype gliomas (all P < 0.05). Using multivariable logistic regression, the entropy of Ktrans, skewness of Ve, and Kapp-90th had higher prediction potential for IDH mutations with areas under the ROC curve (AUC) of 0.915, 0.735, and 0.830, respectively. A combination of these analyses for the identification of IDH mutation improved the AUC to 0.978, with a sensitivity and specificity of 94.1% and 96.0%, respectively, which was higher than the single analysis (P < 0.05). CONCLUSION: Integrating the TA of DCE-MRI and histogram analysis of DKI may help to predict the IDH mutational status.


Assuntos
Neoplasias Encefálicas , Glioma , Humanos , Isocitrato Desidrogenase/genética , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Estudos Retrospectivos , Glioma/diagnóstico por imagem , Glioma/genética , Glioma/patologia , Imageamento por Ressonância Magnética/métodos , Mutação
11.
Small ; 17(6): e2007264, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33470516

RESUMO

Developing a rapid and low cost approach to access atomically dispersed metal catalysts (ADMCs) supported by carbon is important but still challenging. Here, an electric flash strategy using high voltage for the rapid fabrication of carbon-supported ADMCs within 1 min is reported. Continuous plasma arc results in nitrogen-doped carbon ultrathin nanosheets, while an intermittent spark pulse constructs carbon hollow nanospheres via blasting effect, and both structures are decorated with atomically dispersed cobalt. The latter catalyst shows a half-wave potential of 0.887 V versus RHE (47 mV higher than commercial Pt/C) in an oxygen reduction reaction (ORR) in alkaline media. The authors' work paves the way to rapid synthesis of carbon-supported ADMCs at both low cost and mass production.

12.
Small ; 17(30): e2101008, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34151515

RESUMO

The catalytic properties of supported metal heterostructures critically depend on the design of metal sites. Although it is well-known that the supports can influence the catalytic activities of metals, precisely regulating the metal-support interactions to achieve highly active and durable catalysts still remain challenging. Here, the authors develop a support effect in the oxide-supported metal monomers (involving Pt, Cu, and Ni) catalysts by means of engineering nitrogen-assisted nanopocket sites. It is found that the nitrogen-permeating process can induce the reconstitution of vacancy interface, resulting in an unsymmetrical atomic arrangement around the vacancy center. The resultant vacancy framework is more beneficial to stabilize Pt monomers and prevent diffusion, which can be further verified by the density functional theory calculations. The final Pt-N/SnO2 catalysts exhibit superior activity and stability for HCHO response (26.5 to 15 ppm). This higher activity allows the reaction to proceed at a lower operating temperature (100 °C). Incorporated with wireless intelligent-sensing system, the Pt-N/SnO2 catalysts can further achieve continuous monitoring of HCHO levels and cloud-based terminal data storage.


Assuntos
Óxidos , Platina , Catálise
13.
J Hand Surg Am ; 46(8): 712.e1-712.e6, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33766436

RESUMO

PURPOSE: Current reconstruction strategies for chronic posttraumatic boutonniere deformities have variable outcomes and are prone to complications. This study aimed to describe the clinical outcomes of a Y-shaped tendon graft technique. METHODS: In this retrospective case study, we reviewed the files of 18 patients treated with the Y-shaped tendon graft between January 2010 and January 2017. The technique involves release of the central slip, lateral bands, and transverse retinacular ligaments at the proximal interphalangeal (PIP) joint, total excision of scar tissue in the central slip and at the insertion site, and construction of 3 1.5-mm unicortical holes at the base of the middle phalanx, through which a Y-shaped graft of the palmaris longus is inserted to reconstruct the central slip and stabilize the lateral bands in a dorsal position. Clinical evaluations included measuring the active range of motion in the PIP joint and distal interphalangeal (DIP) joint, grip strength, Souter score, and the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score. RESULTS: The mean age of patients was 36.1 years, and 12 of the 18 patients were men. The average follow-up period was 23 months (range, 13-38 months). The preoperative PIP joint extension deficit was 48.0° ± 5.0° compared with 10.9° ± 9.3° after surgery. The preoperative DIP joint active flexion was 34.4° ± 8.0° compared with 71.4° ± 8.6° after surgery The outcomes based on the Souter score were 11 excellent, 5 good, and 2 poor. The QuickDASH score was 17.7 ± 6.4 before surgery and 11.2 ± 7.2 after surgery. CONCLUSIONS: The Y-shaped tendon graft can be a useful procedure for the correction of chronic boutonniere deformity; in our patient series, this provided good or excellent results in 16 of 18 patients. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.


Assuntos
Deformidades Adquiridas da Mão , Procedimentos Ortopédicos , Adulto , Articulações dos Dedos/cirurgia , Deformidades Adquiridas da Mão/etiologia , Deformidades Adquiridas da Mão/cirurgia , Humanos , Masculino , Amplitude de Movimento Articular , Estudos Retrospectivos , Tendões/cirurgia
14.
Pak J Med Sci ; 37(2): 520-524, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33679943

RESUMO

OBJECTIVE: To explore the effect of dexmedetomidine hydrochloride on perioperative inflammation and postoperative lung infection in patients with spinal tuberculosis. METHOD: A double-blind control observation was conducted in spinal tuberculosis patients with the use of general anesthesia during the operation. A total of 171 spinal tuberculosis patients who received endotracheal intubation for general anesthesia in Henan University of Chinese Medicine from January 2017 to April 2019 were included. The concentration changes in serum TNF-α and IL-6 were recorded at one hour, six hour and one day after the operation. The incidence of postoperative pulmonary complications of patients were also evaluated. RESULTS: The results showed that in the experimental group compared with the control group, serum TNF-α and IL-6 concentrations one hour, six hour and one day after the operation were significantly lower (P<0.05). The rate of postoperative pulmonary complications was lower in the experimental group than that in the control group (P<0.05). CONCLUSION: Dexmedetomidine hydrochloride has obvious anti-inflammatory effects and can reduce the incidence of pulmonary complications after surgery.

15.
Angew Chem Int Ed Engl ; 60(12): 6533-6538, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33350566

RESUMO

Developing highly stable and efficient catalysts toward the oxygen reduction reaction is important for the long-term operation in proton exchange membrane fuel cells. Reported herein is a facile synthesis of two-dimensional coplanar Pt-carbon nanomeshes (NMs) that are composed of highly distorted Pt networks (neck width of 2.05±0.72 nm) and carbon. X-ray absorption fine structure spectroscopy demonstrated the metallic state of Pt in the coplanar Pt/C NMs. Fuel cell tests verified the excellent activity of the coplanar Pt/C NM catalyst with the peak power density of 1.21 W cm-2 and current density of 0.360 A cm-2 at 0.80 V in the H2 /O2 cell. Moreover, the coplanar Pt/C NM electrocatalysts showed superior stability against aggregation, with NM structures preserved intact for a long-term operation of over 30 000 cycles for electrode measurement, and the working voltage loss was negligible after 120 h in the H2 /O2 single cell operation. Density-functional theory analysis indicates the increased vacancy formation energy of Pt atoms for coplanar Pt/C NMs, restraining the tendency of Pt dissolution and aggregation.

16.
J Am Chem Soc ; 142(29): 12643-12650, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32584563

RESUMO

The controllable synthesis of stable single-metal site catalysts with an expected coordination environment for high catalytic activity and selectivity is still challenging. Here, we propose a cation-exchange strategy for precise production of an edge-rich sulfur (S) and nitrogen (N) dual-decorated single-metal (M) site catalysts (M = Cu, Pt, Pd, etc.) library. Our strategy relies on the anionic frameworks of sulfides and N-rich polymer shell to generate abundant S and N defects during high-temperature annealing, further facilitating the stabilization of exchanged metal species with atomic dispersion and excellent accessibility. This process was traced by in situ transmission electron microscopy, during which no metal aggregates were observed. Both experiments and theoretical results reveal the precisely obtained S, N dual-decorated Cu sites exhibit a high activity and low reaction energy barrier in catalytic hydroxylation of benzene at room temperature. These findings provide a route to controllably produce stable single-metal site catalysts and an engineering approach for regulating the central metal to improve catalytic performance.

17.
Chemistry ; 26(18): 4019-4024, 2020 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-31571290

RESUMO

Engineering noble metal nanostructures at the atomic level can significantly optimize their electrocatalytic performance and remarkably reduce their usage. We report the synthesis of atomically dispersed Pt on screw-like Pd/Au nanowires by using ultrafine Pd nanowires as seeds. Au can selectively grow on the surface of Pd nanowires by an island growth pattern to fabricate surface defect sites to load atomically dispersed Pt, which can be confirmed by X-ray absorption fine structure measurements and aberration corrected HRTEM images. The nanowires with 2.74 at % Pt exhibit superior HER properties in acidic solution with an overpotential of 20.6 mV at 10 mA cm-2 and enhanced alkaline ORR performance with a mass activity over 15 times greater than the commercial platinum/carbon (Pt/C) catalysts.

18.
J Magn Reson Imaging ; 51(5): 1507-1513, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31769565

RESUMO

BACKGROUND: Preoperative evaluation of the consistency of pituitary macroadenomas is important for neurosurgeons to prepare the surgical plan. PURPOSE: To evaluate the diagnostic performance of texture analysis (TA) of diffusion-weighted imaging (DWI) at a standard b-value (b = 1000 s/mm2 ) and a high b-value (b = 2000 s/mm2 ) for their ability to assess the tumor consistency of pituitary macroadenomas. STUDY TYPE: Retrospective. POPULATION/SUBJECTS: Fifty patients with histologically confirmed pituitary macroadenomas were classified as soft (n = 37) or hard (n = 13) types. FIELD STRENGTH/SEQUENCE: Coronal T2 -weighted imaging (T2 WI), Readout Segmentation of Long Variable Echo-trains (RESOLVE) DWI at b = 1000 s/mm2 and b = 2000 s/mm2 were acquired with 3.0T MRI. ASSESSMENT: The corresponding apparent diffusion coefficient (ADC) maps (ADC1000 and ADC2000 ) were registered to T2 WI. Regions of interest (ROIs) were manually drawn along the solid part of the tumor from the coregistered T2 WI-ADC images. The texture parameters from T2 WI, ADC1000 , and ADC2000 were acquired. STATISTICAL TESTS: The texture parameters were compared between the two types by using unpaired Student's t-test. Receiver operating characteristic (ROC) curves and logistic regression analyses were used to assess their diagnostic performance. RESULTS: Significant differences in TA parameters of ADC1000 and ADC2000 were observed between soft and hard types (P < 0.05 for all), whereas the TA of T2 WI resulted in no significant difference (P > 0.05 for all). TA of ADC2000 provided a superior diagnostic performance compared with that of ADC1000 (P = 0.038). A combination of mean value and entropy of ADC2000 yielded an AUC, a sensitivity, and a specificity of 0.911, 78.4% and 92.3%, respectively. DATA CONCLUSION: TA of ADC values were useful for assessing the tumor consistency of pituitary macroadenomas. ADC2000 may facilitate better type discrimination. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1507-1513.


Assuntos
Imagem de Difusão por Ressonância Magnética , Neoplasias Hipofisárias , Humanos , Imageamento por Ressonância Magnética , Neoplasias Hipofisárias/diagnóstico por imagem , Curva ROC , Estudos Retrospectivos
19.
Eur Radiol ; 30(6): 3059-3065, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32064562

RESUMO

INTRODUCTION: We aimed to investigate the utility of compressed sensing time-of-flight magnetic resonance angiography (CS TOF-MRA) for diagnosing intracranial and cervical arterial stenosis by using digital subtraction angiography (DSA) as the reference standard. METHODS: Thirty-seven patients with head and neck arterial stenoses who underwent CS TOF-MRA and DSA were retrospectively enrolled. The reconstructed resolution of CS TOF-MRA was 0.4 × 0.4 × 0.4 mm3. The scan time was 5 min and 2 s. The image quality of CS TOF-MRA was independently ranked by two neuroradiologists in 1031 arterial segments. The luminal stenosis grades on CS TOF-MRA and DSA were analyzed in 61 arterial segments and were compared using the Wilcoxon signed-rank test. The ability of CS TOF-MRA to predict moderate to severe stenosis or occlusion was analyzed. RESULTS: The image quality of most arterial segments (95.2%) on CS TOF-MRA was excellent. Arterial segments with low image quality were mainly the V3-4 segments of the vertebral artery. The majority of arterial stenoses (62.3%) were located in the cervical internal carotid artery. The luminal stenosis grades of CS TOF-MRA were concordant with that of DSA in 50 of 61 segments (p = 0.366). CS TOF-MRA had a sensitivity of 84.4% and a specificity of 88.5% for predicting moderate to severe stenosis. For detecting occlusion lesions, it had a sensitivity of 100% and a specificity of 94.1%. CONCLUSION: CS TOF-MRA provides adequate image quality within a reasonable acquisition time and is a reliable tool for diagnosing head and neck arterial steno-occlusive disease. KEY POINTS: • CS TOF-MRA provides a relatively large coverage (16 cm), high resolution (0.4 × 0.4 × 0.4 mm3) and good image quality of head and neck arteries within 5 min and 2 s. • The diagnostic accuracy of CS TOF-MRA in the assessment of moderate to severe stenosis and occlusion was comparable with that of DSA. • Arterial segments with low image quality were mainly the V3 and V4 segments of the vertebral artery.


Assuntos
Angiografia Digital/métodos , Arteriopatias Oclusivas/diagnóstico , Artéria Carótida Interna/diagnóstico por imagem , Angiografia por Ressonância Magnética/métodos , Artéria Vertebral/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC , Reprodutibilidade dos Testes , Estudos Retrospectivos
20.
Pak J Med Sci ; 36(3): 559-564, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32292471

RESUMO

OBJECTIVE: To discuss the function of mixed reality (MR) technology in guiding location of intervertebral foramen microscopic puncture and analyze its feasibility and clinical application value. METHODS: Sixty patients with lumbar intervertebral disc who were treated between January 2017 to October 2017 were chosen, and classified into navigation group (30 cases) and traditional control (30 cases) according to random number table. Intervertebral foramen microscopic operation was conducted for both groups. MR technology was applied for the navigation group to guide puncture and establish intervertebral foramen microscopic cannula. Traditional C-arm X-ray apparatus was used for traditional group to establish intervertebral foramen microscopic cannula. Intra-operative puncture times, fluoroscopy times, puncture time and VAS score 1d, 3m and 6m after the operation were recorded and compared. RESULTS: Postoperative waist and leg pain symptoms of both groups were relieved obviously, and straight leg raising test for the diseased limb turned to be negative. Intra-operative puncture times, fluoroscopy times, puncture time and operation time had statistical significance decrease. CONCLUSION: Mixed reality (MR) can accurately guide the establishment of intervertebral foramen microscopic cannula, solve the bottleneck problem of intervertebral foramen microscopic technology, promote puncture success rate, reduce repeated puncture times, avoid by-injury, shorten puncture time and reduce X-ray radiation quantity of operators and patients, so it deserves to be promoted and applied.

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