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1.
Int Orthop ; 44(6): 1153-1157, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32303792

RESUMO

PURPOSE: To investigate the union rate after lunatocapitate arthrodesis for the treatment of scaphoid nonunion advanced collapse (SNAC) wrists and to evaluate the clinical results of this technique. METHODS: We conducted a prospective study between January 2014 and July 2017. Fifteen males with painful stage III SNAC wrists (average age, 32 years, range, 20-37 years; average follow-up time, 25.2 months, range, 20-36 months) underwent scaphoid excision and lunatocapitate fusion. Lunatocapitate fusions were fixed with headless Herbert screws with K-wire fixation (retrograde direction). Radiographs, wrist range of motion, and Mayo wrist score were examined. RESULTS: All patients achieved radiographic and clinical union after lunatocapitate fusion during follow-up (average 10 months post-operatively). The flexion-extension arc was 70°, and the average Mayo wrist score was 74.3 points (eight with excellent, four with good, three with satisfactory, and one with poor result). Thirteen patients returned to work, whereas two with nonunion required surgical graft revision. Complete union was achieved at an average of 12 weeks after graft revision, with improved range of motion, and the patients returned to work with a change in their occupation. CONCLUSIONS: Lunatocapitate arthrodesis is a satisfactory therapeutic alternative to four-corner fusion for SNAC wrists.

2.
Orthop Surg ; 12(1): 170-176, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31916389

RESUMO

OBJECTIVE: To evaluate the effect of including the fractured vertebra in the short-segment fixation of thoracolumbar (TL) fractures. METHODS: A total of 32 patients with thoraco-lumbar fractures, selected between August 2013 and February 2016, were managed by short-segment fixation with screws at the level of the fracture, and decompression was performed only for patients with neurological deficits. The patients' functional outcome was assessed using the visual analogue scale (VAS) score for pain and the American Spinal Injury Association (ASIA) score for neurological condition. All patients were followed up with radiographs. RESULTS: Patients with complete neurologic deficits (n = 3) did not show any neurologic recovery. All ASIA B patients improved to ASIA C. Five ASIA C patients improved to ASIA E. The remaining five ASIA C patients improved to ASIA D. All ASIA D patients improved to ASIA B. At the final follow-up examination, the mean anterior vertebral height was 21 ± 5 mm, indicating no significant height loss during the follow-up period. CONCLUSION: Short-segment fixation of TL fractures with inclusion of the fracture level into the construct offers good correction of segmental kyphosis, vertebral wedging, and vertebral height loss.


Assuntos
Fixação Interna de Fraturas/métodos , Vértebras Lombares/cirurgia , Parafusos Pediculares , Fraturas da Coluna Vertebral/cirurgia , Vértebras Torácicas/cirurgia , Adolescente , Adulto , Feminino , Fixação Interna de Fraturas/instrumentação , Humanos , Vértebras Lombares/lesões , Masculino , Pessoa de Meia-Idade , Medição da Dor , Vértebras Torácicas/lesões , Adulto Jovem
3.
Knee Surg Sports Traumatol Arthrosc ; 26(8): 2395-2400, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29159673

RESUMO

PURPOSE: A comparison of clinical outcomes between double-bundle (DB) and single-bundle (SB) anterior cruciate ligament (ACL) reconstruction for patients with ACL injury. METHODS: Sixty patients were treated with either SB (n = 30) or DB (n = 30) ACL reconstruction between 2011 and 2012. The hamstring tendons were autografted with suspensory fixation on the femoral side, while a bio-absorbable interference screw was used for fixation on the tibial side. These patients were evaluated using Lysholm score, International Knee Documentation Committee (IKDC) forms (both objective and subjective), Lachman test, pivot shift test, and KT 1000 arthrometer. RESULTS: After a median follow-up duration of 35.5 months (ranging between 30 and 42 months), the frequency of patients who had high objective IKDC scores was significantly higher in the DB group than those in the SB group. In terms of DB, the Lachman test was normal in 26 patients (86.7%), nearly normal in three patients (10%), and abnormal in one patient (3.3%); comparatively, in terms of SB, the Lachman test was normal in 20 patients (66.7%), nearly normal in eight patients (26.7%) and abnormal in two patients (6.6%). The pivot shift test was negative in 29 patients (96.7%) and 21 patients (70%) for DB and SB, respectively. The average KT-1000 side-to-side difference was 1.0 mm for DB and 1.5 mm for SB. The subjective IKDC and Lysholm score showed non-significant differences between both techniques. CONCLUSION: Double-bundle ACL reconstruction was found to have a significant advantage in anterior and rotational stability as well as objective IKDC than that of SB reconstruction. However, subjective measurements showed no statistical differences between the techniques. LEVEL OF EVIDENCE: II.


Assuntos
Lesões do Ligamento Cruzado Anterior/cirurgia , Reconstrução do Ligamento Cruzado Anterior/métodos , Adolescente , Adulto , Parafusos Ósseos , Feminino , Fêmur/cirurgia , Tendões dos Músculos Isquiotibiais/transplante , Humanos , Instabilidade Articular/diagnóstico , Masculino , Exame Físico , Tíbia/cirurgia , Transplante Autólogo , Resultado do Tratamento , Adulto Jovem
4.
Nanoscale ; 9(41): 15865-15872, 2017 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-28994845

RESUMO

Exploring highly efficient bifunctional electrocatalysts toward the oxygen reduction and evolution reactions is essential for the realization of high-performance rechargeable zinc-air batteries. Herein, a novel nanofibrous bifunctional electrocatalyst film, consisting of metallic manganese sulfide and cobalt encapsulated by nitrogen-doped carbon nanofibers (CMS/NCNF), is prepared through a continuous electrospinning method followed by carbonization treatment. The CMS/NCNF bifunctional catalyst shows both comparable ORR and OER performances to those of commercial precious metal-based catalysts. Furthermore, the free-standing CMS/NCNF fibrous thin film is directly used as the air electrode in a solid-state zinc-air battery, which exhibits superior flexibility while retaining stable battery performance at different bending angles. This study provides a versatile design route for the rational design of free-standing bifunctional catalysts for direct use as the air electrode in rechargeable zinc-air batteries.

5.
Adv Mater ; 29(35)2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28714123

RESUMO

A critical bottleneck limiting the performance of rechargeable zinc-air batteries lies in the inefficient bifunctional electrocatalysts for the oxygen reduction and evolution reactions at the air electrodes. Hybridizing transition-metal oxides with functional graphene materials has shown great advantages due to their catalytic synergism. However, both the mediocre catalytic activity of metal oxides and the restricted 2D mass/charge transfer of graphene render these hybrid catalysts inefficient. Here, an effective strategy combining anion substitution, defect engineering, and the dopant effect to address the above two critical issues is shown. This strategy is demonstrated on a hybrid catalyst consisting of sulfur-deficient cobalt oxysulfide single crystals and nitrogen-doped graphene nanomeshes (CoO0.87 S0.13 /GN). The defect chemistries of both oxygen-vacancy-rich, nonstoichiometric cobalt oxysulfides and edge-nitrogen-rich graphene nanomeshes lead to a remarkable improvement in electrocatalytic performance, where CoO0.87 S0.13 /GN exhibits strongly comparable catalytic activity to and much better stability than the best-known benchmark noble-metal catalysts. In application to quasi-solid-state zinc-air batteries, CoO0.87 S0.13 /GN as a freestanding catalyst assembly benefits from both structural integrity and enhanced charge transfer to achieve efficient and very stable cycling operation over 300 cycles with a low discharge-charge voltage gap of 0.77 V at 20 mA cm-2 under ambient conditions.

6.
ACS Appl Mater Interfaces ; 9(24): 20603-20612, 2017 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-28557416

RESUMO

Tuned chalcogenide single crystals rooted in sulfur-doped graphene were prepared by high-temperature solution chemistry. We present a facile route to synthesize a rod-on-sheet-like nanohybrid as an active anode material and demonstrate its superior performance in lithium ion batteries (LIBs). This nanohybrid contains a nanoassembly of one-dimensional (1D) single-crystalline, orthorhombic SnS onto two-dimensional (2D) sulfur-doped graphene. The 1D nanoscaled SnS with the rodlike single-crystalline structure possesses improved transport properties compared to its 2D hexagonal platelike SnS2. Furthermore, we blend this hybrid chalcogenide with biodegradable polymer composite using water as a solvent. Upon drying, the electrodes were subjected to heating in vacuum at 150 °C to induce polymer condensation via formation of carboxylate groups to produce a mechanically robust anode. The LIB using the as-developed anode material can deliver a high volumetric capacity of ∼2350 mA h cm-3 and exhibit superior cycle stability over 1500 cycles as well as a high capacity retention of 85% at a 1 C rate. The excellent battery performance combined with the simplistic, scalable, and green chemistry approach renders this anode material as a very promising candidate for LIB applications.

7.
ACS Appl Mater Interfaces ; 9(11): 9551-9558, 2017 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-27808493

RESUMO

A novel self-supported electrode with long cycling life and high mass loading was developed based on carbon-coated Si nanowires grown in situ on highly conductive and flexible carbon fabric substrates through a nickel-catalyzed one-pot atmospheric pressure chemical vapor deposition. The high-quality carbon coated Si nanowires resulted in high reversible specific capacity (∼3500 mA h g-1 at 100 mA g-1), while the three-dimensional electrode's unique architecture leads to a significantly improved robustness and a high degree of electrode stability. An exceptionally long cyclability with a capacity retention of ∼66% over 500 cycles at 1.0 A g-1 was achieved. The controllable high mass loading enables an electrode with extremely high areal capacity of ∼5.0 mA h cm-2. Such a scalable electrode fabrication technology and the high-performance electrodes hold great promise in future practical applications in high energy density lithium-ion batteries.

8.
Adv Mater ; 29(7)2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27982465

RESUMO

Rich, porous graphene frameworks decorated with uniformly dispersed active sites are prepared by using polyaniline as a graphene precursor and introducing phenanthroline as a pore-forming agent. The unprecedented fuel-cell performance of this electrocatalyst is linked to the graphene frameworks with vast distribution of pore sizes, which maximizes the active-sites accessibility, facilitates mass-transport properties, and improves the carbon corrosion resistance.

9.
Adv Mater ; 28(30): 6420, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27493071

RESUMO

On page 6421, Z. Chen and co-workers describe an electrically rechargeable, nanoarchitectured air electrode that morphologically emulates a human-hair array for solid-state zinc-air batteries. Grown directly on a stainless-steel mesh, the hair-like array can effectively catalyze molecular oxygen to water. Batteries equipped with this electrode show tangible benefits, including improved flexibility and performance.


Assuntos
Ar , Biomimética , Fontes de Energia Elétrica , Cabelo/anatomia & histologia , Zinco/química , Catálise , Eletrodos , Humanos , Oxigênio/química , Aço Inoxidável , Água/química
10.
Adv Mater ; 28(30): 6421-8, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27197721

RESUMO

An electrically rechargeable, nanoarchitectured air electrode that morphologically emulates a human hair array is demonstrated in a zinc-air battery. The hair-like array of mesoporous cobalt oxide nanopetals in nitrogen-doped carbon nanotubes is grown directly on a stainless-steel mesh. This electrode produces both flexibility and improved battery performance, and thus fully manifests the advantages of flexible rechargeable zinc-air batteries in practical applications.

11.
ACS Appl Mater Interfaces ; 8(10): 6488-95, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26937737

RESUMO

Nitrogen-functionalized graphene materials have been demonstrated as promising electrocatalyst for the oxygen reduction reaction (ORR), owning to their respectable activity and excellent stability in alkaline electrolyte. However, they exhibit unacceptable catalytic activity in acid medium. Here, a hierarchically porous Co-N functionalized graphene aerogel is prepared as an efficient catalyst for the ORR in acid electrolyte. In the preparation process, polyaniline (PANI) is introduced as a pore-forming agent to aid in the self-assembly of graphene species into a porous aerogel networks, and a nitrogen precursor to induce in situ nitrogen doping. Therefore, a Co-N decorated graphene aerogel framework with a large surface area (485 m(2) g(-1)) and an abundance of meso/macropores is effectively formed after heat treatment. Such highly desired structures can not only expose sufficient active sites for the ORR but also guarantee the fast mass transfer in the catalytic process, which provides significant catalytic activity with positive onset and half wave potentials, low hydrogen peroxide yield, high resistance to methanol crossover, and remarkable stability that is comparable to commercial Pt/C in acid medium.

12.
ACS Appl Mater Interfaces ; 8(3): 1984-91, 2016 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-26742576

RESUMO

To meet the requirements of both high energy and power density with cycle durability of modern EVs, we prepared a novel nanosulfur granular assembled film coated on the three-dimensional graphene sponge (3D-GS) composite as a high-performance active material for rechargeable lithium sulfur batteries. Instead of conventional graphene powder, three-dimensional rGO sponge (3D-rGO) is employed for the composite synthesis, resulting in a sulfur film directly in contact with the underlying graphene layer. This significantly improves the overall electrical conductivity, strategically addressing challenges of conventional composites of low sulfur utilization and dissolution of polysulfides. Additionally, the synthesis mechanism of 3D-GS is elucidated by XPS and DFT analyses, where replacement of hydroxyl group of 3D-rGO sponge by sulfur (S8) is found to be thermodynamically favorable. As expected, 3D-GS demonstrates outstanding discharge capacity of 1080 mAh g(-1) at a 0.1C rate, and 86.2% capacity retention even after 500 cycles at a 1.0C rate.

13.
Nat Commun ; 6: 8597, 2015 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-26497228

RESUMO

Silicon has the potential to revolutionize the energy storage capacities of lithium-ion batteries to meet the ever increasing power demands of next generation technologies. To avoid the operational stability problems of silicon-based anodes, we propose synergistic physicochemical alteration of electrode structures during their design. This capitalizes on covalent interaction of Si nanoparticles with sulfur-doped graphene and with cyclized polyacrylonitrile to provide a robust nanoarchitecture. This hierarchical structure stabilized the solid electrolyte interphase leading to superior reversible capacity of over 1,000 mAh g(-1) for 2,275 cycles at 2 A g(-1). Furthermore, the nanoarchitectured design lowered the contact of the electrolyte to the electrode leading to not only high coulombic efficiency of 99.9% but also maintaining high stability even with high electrode loading associated with 3.4 mAh cm(-2). The excellent performance combined with the simplistic, scalable and non-hazardous approach render the process as a very promising candidate for Li-ion battery technology.

14.
Adv Mater ; 27(37): 5617-22, 2015 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-26305154

RESUMO

A thin-film, flexible, and rechargeable zinc-air battery having high energy density is reported particularly for emerging portable and wearable electronic applications. This freeform battery design is the first demonstrated by sandwiching a porous-gelled polymer electrolyte with a freestanding zinc film and a bifunctional catalytic electrode film. The flexibility of both the electrode films and polymer electrolyte membrane gives great freedom in tailoring the battery geometry and performance.

15.
Adv Mater ; 27(7): 1229-34, 2015 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-25417577

RESUMO

Direct growth of multigrain platinum nanowires on sulfur-doped graphene (PtNW/SG) is reported. The growth mechanism, including Pt nanoparticle nucleation on SG, followed by nanoparticle attachment with orientation along the <111> direction is highlighted. PtNW/SG demonstrates improved Pt mass and specific activity compared with commercial catalysts toward oxygen reduction, in addition to dramatically improved stability through accelerated durability testing.

16.
ACS Appl Mater Interfaces ; 6(16): 13757-64, 2014 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-25077883

RESUMO

A novel one-pot synthesis for the subeutectic growth of (111) oriented Si nanowires on an in situ formed nickel nanoparticle catalyst prepared from an inexpensive nickel nitrate precursor is developed. Additionally, anchoring the nickel nanoparticles to a simultaneously reduced graphene oxide support created synergy between the individual components of the c-SiNW-G composite, which greatly improved the reversible charge capacity and it is retention at high current density when applied as an anode for a Li-ion battery. The c-SiNW-G electrodes for Li-ion battery achieved excellent high-rate performance, producing a stable reversible capacity of 550 mAh g(-1) after 100 cycles at 6.8 A g(-1) (78% of that at 0.1 A g(-1)). Thus, with further development this process creates an important building block for a new wave of low-cost silicon nanowire materials and a promising avenue for high rate Li-ion batteries.

17.
Nano Lett ; 14(1): 277-83, 2014 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-24329030

RESUMO

A novel, economical flash heat treatment of the fabricated silicon based electrodes is introduced to boost the performance and cycle capability of Li-ion batteries. The treatment reveals a high mass fraction of Si, improved interfacial contact, synergistic SiO2/C coating, and a conductive cellular network for improved conductivity, as well as flexibility for stress compensation. The enhanced electrodes achieve a first cycle efficiency of ∼84% and a maximum charge capacity of 3525 mA h g(-1), almost 84% of silicon's theoretical maximum. Further, a stable reversible charge capacity of 1150 mA h g(-1) at 1.2 A g(-1) can be achieved over 500 cycles. Thus, the flash heat treatment method introduces a promising avenue for the production of industrially viable, next-generation Li-ion batteries.


Assuntos
Fontes de Energia Elétrica , Lítio/química , Microeletrodos , Nanotecnologia/instrumentação , Silício/química , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Íons
18.
Sci Rep ; 3: 2431, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23942256

RESUMO

Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemical energy conversion and storage technologies; however the simultaneous control of Pt morphology and dispersion, along with ideally tailoring the physical properties of the catalyst support properties has proven very challenging. Using sulfur doped graphene (SG) as a support material, the heterogeneous dopant atoms could serve as nucleation sites allowing for the preparation of SG supported Pt nanowire arrays with ultra-thin diameters (2-5 nm) and dense surface coverage. Detailed investigation of the preparation technique reveals that the structure of the resulting composite could be readily controlled by fine tuning the Pt nanowire nucleation and growth reaction kinetics and the Pt-support interactions, whereby a mechanistic platinum nanowire array growth model is proposed. Electrochemical characterization demonstrates that the composite materials have 2-3 times higher catalytic activities toward the oxygen reduction and methanol oxidation reaction compared with commercial Pt/C catalyst.

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