[Scarf osteotomy combined with soft tissue balance release for severe hallux valgus].

OBJECTIVE: To explore clinical effect of Scarf osteotomy combined with soft tissue balance in treating severe hallux valgus. METHODS: Totally 38 patients(50 feet) with severe hallux valux who underwent Scarf osteotomy combined with soft tissue balance surgery from June 2019 to June 2021 were retrospectively analyzed, aged from 29 to 64 years old with an average of(54.7±6.8) years old; 26 feet on the left side and 24 feet on the right side;the courses of disease ranged from 5 to 23 years with an average of (12.4±3.9) years. Hallux valgus angle (HVA), intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA) were compared before and after operation, and postoperative complications was observed. American orthopedic foot ankle society(AOFAS) score before operation and final follow-up was used to evaluate recovery of forefoot function, and visual analogue scale (VAS) was used to evaluate pain relief. RESULTS: Thirty-eight patients (50 feet) were followed up from 15 to 23 months with an average of (18.3±3.2) months. Preoperative HVA, IMA and DMAA were (44.61±3.92)°, (18.74±2.51)°, (12.85±2.11)°, and improved to (13.45±2.13)°, (7.83±1.36)°, (7.03±1.39)°at final follow-up, which had statistical differneces(P<0.05). No delayed union or nonunion of osteotomy end, fracture or loosening of internal fixation, hallux varus occurred. VAS and AOFAS score improved from (6.81±2.14), (43.6±8.4)points before operation to (1.97±0.78), (87.6±5.2) points at final follow-up, which had statistical difference(P<0.01). According to AOFAS at final follow-up, 20 feet got excellent result, 28 feet good and 2 feet moderate. CONCLUSION: Scarf osteotomy combined with soft tissue balance release for severe hallux valgus has good stability and corrective effect, but learning curve and postoperative complications should be paid attention.

Fe3O4 Nanoparticle/N-Doped Carbon Hierarchically Hollow Microspheres for Broadband and High-Performance Microwave Absorption at an Ultralow Filler Loading.

Although the existing Fe3O4-based microwave absorbing materials (MAMs) have shown promising microwave absorbing (MA) capacity, it is highly desired but still remains a great challenge to achieve strong minimum reflection loss (RLmin) and broad effective frequency bandwidth (fe) at an ultralow filler loading. Herein, for the first time, by carbonizing hierarchical poly(urea-formaldehyde) microcapsules with Fe3O4 nanoparticle cores in a nitrogen atmosphere, Fe3O4 hybrid and N-doped hollow carbon microspheres (Fe3O4/CMs) with a hierarchical micro/nanostructure are prepared on a large scale and at a low cost to achieve extremely superior MA performances. Benefitting from their unique structure and diverse composition, which synergetically contribute to good impedance matching, strong dielectric/magnetic loss, and abundant multiscattering/reflection, Fe3O4/CM composites possessed a RLmin value reaching -60.3 dB and an fe of as broad as 6.4 GHz (7.2-13.6 GHz, covering the full X-band) at an ultralow filler loading of 10 wt % in paraffin wax, which are significantly superior to those of the previously reported state-of-the-art Fe3O4-based or hollow MAMs. Furthermore, the fe can be adjusted in the range of 4.5-18 GHz, covering 85% of the whole measured frequency range, via changing the thickness between 2.5 and 5.5 mm. This work offers new insights for developing advanced lightweight MAMs with strong absorption and a broad absorbing frequency range at a low filler loading.

Ultralight Three-Dimensional Hierarchical Cobalt Nanocrystals/N-Doped CNTs/Carbon Sponge Composites with a Hollow Skeleton toward Superior Microwave Absorption.

It is extremely desirable but remains greatly challenging to obtain high-performance microwave absorption (MA) materials with thin thickness, lightweight, wide frequency bandwidth, and strong absorption by facile and low-cost preparing methods. In this work, by utilizing an inexpensively commercial melamine-formaldehyde sponge (MFS) as a template for growth of a Co-based metal-organic framework (ZIF-67) and subsequently carbonizing this ZIF-67-decorated MFS in a nitrogen atmosphere, an ultralight (8 mg cm-3), three-dimensional hybrid carbon sponge composite with a hierarchical micro/nanostructure and hollow skeleton is successfully prepared to acquire excellent MA performances for the first time. The as-obtained composite consisted of interconnected carbon microtubes as a skeleton, intertwined N-doped carbon nanotubes (CNTs) grew on the outer surface of the carbon microtubes, and metallic Co nanocrystals encapsulated at the tips of the CNTs. Benefiting from the unique architecture and hierarchical composite which contribute to a good conductive network, moderate magnetic loss, strong matched impedance, and multiple polarization, the composite (Co/CNTs/CS) exhibited a minimum reflection loss (RL) of -51.2 dB and an effective absorption bandwidth (EAB, RL < -10 dB) of 4.1 GHz with a matching thickness of 2.2 mm at a filler loading of as low as 10 wt % in paraffin wax. Even with the thickness of 1.6 mm or at the filler loading of 5 wt %, the composites can also gain the low minimum RL value of -30.9 or -17.9 dB, respectively. In addition, the largest EAB was 5.4 GHz at the thickness of 2.0 mm, and the tunable EAB can be achieved in the range of 3.6-18 GHz, covering 90% of the measured frequency range via adjusting the absorber thickness between 1 and 5.5 mm. The results offer new insights for designing advanced microwave absorbers with lightweight, thin thickness, strong RL, and wide absorption frequency range.