Copper-induced synthesis of palladium/copper popcorn nanoparticles as sensors for differential pulse voltammetric determination of dopamine.

Popcorn nanoparticles (pop-NPs) consisting of a Pd/Cu alloy were synthesized using a seed-mediated growth method. The Cu and Pd atoms were co-deposited on a cubic Pd seed to reduce the energy of fault stacking. The same synthesis method with a reduced volume of the Cu(II) salt leads to Pd/Cu alloy nanoparticles with branches (br-NPs). Large Pd nanocubes (Pd NCs) were prepared via epitaxial deposition and using tetrachloropalladate (PdCl42-) only. The high-resolution TEM analysis results show the pop-NPs and br-NPs to be single crystals with [Formula: see text] and [Formula: see text] planes, respectively. The results of X-ray photoelectron spectroscopy and cyclic voltammetry measurements corroborated that Pd is enriched on both surfaces. The materials were placed on a glassy carbon electrode to obtain a differential pulse voltammetric sensor for dopamine (DA). The electrochemical sensitivities are (a) 1.55 µA µM-1 cm-2 for the Pd/Cu pop-NP sensor in its linear range (15-300 µM), (b) 1.17 µA µM-1 cm-2 for the br-NP sensor in the linear range (15-200 µM), and (c) 0.97 µA µM-1 cm-2 for the Pd NC sensor in its linear range (15-100 µM). The best working potentials are near 0.10 V (vs. SCE) for all three sensors. The pop-NP-based sensor performs particularly well due to it selectivity over ascorbic and uric acid. Graphical abstract Pd/Cu popcorn nanoparticles (pop-NPs), nanoparticles with branches (br-NPs), and Pd nanocubes (NCs) were synthesized using seed-mediated growth methods and directly used on glassy carbon electrodes for non-enzymatic sensing of dopamine.

Management of Juvenile Hallux Valgus Deformity: the role of combined Hemiepiphysiodesis.

BACKGROUND: This study aimed to investigate the efficacy of percutaneous hemiepiphysiodesis for gradual correction of symptomatic juvenile hallux valgus (HV) deformity. METHODS: Between 2012 to 2014, 24 patients with symptomatic juvenile HV were treated by combined percutaneous medial drilling hemiepiphysiodesis of the first proximal phalanx and lateral transphyseal screw hemiepiphysiodesis of the first metatarsal at our institution. Twenty-one of 24 patients fulfilled inclusion criteria had a complete radiological and clinical follow-up of at least 2 years. Preoperative and postoperative radiographs of the feet were reviewed for measurements of hallux valgus angle (HVA), intermetatarsal angle (IMA), proximal metatarsal articular angle (PMAA), proximal phalangeal articular angle (PPAA), and metatarsal length ratio (MTLR). Clinical outcomes were assessed using the AOFAS hallux metatarsophalangeal-interphalangeal score. RESULTS: The study included 21 consecutive patients (37 ft) for analysis. The mean age at surgery was 12.0 years (SD = 1.3) and mean follow-up after surgery was 35.1 months (SD = 6.0). With the data available, the HV deformity improved in terms of the reduction of HVA by a mean of 4.7 degrees (P < .001) and the reduction of IMA by 2.2 degrees (P < .001). The PMAA and PPAA also improved significantly in the anteroposterior plane; however, the PMAA difference was insignificant in lateral plane as expected. The mean difference in the MTLR was 0.00 (P = .216) which was indicative of no length discrepancy between first and second metatarsals. The AOFAS score increased from 68.7 to 85.2 (P < .001). In correlation analysis, time to physeal closure was significantly correlated with the final HVA change (r = -.611, P = .003). CONCLUSION: Although combined hemiepiphysiodesis does not create a large degree of correction as osteotomy, yet it did improve HV deformity with adequate growth remaining in our series. It is a procedure that can be of benefit to patients with symptomatic juvenile HV from this minimal operative approach before skeletal maturity. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Does fully-threaded Headless Compression Screw provide a length-stable fixation in undisplaced femoral neck fractures?

OBJECTIVE: Femoral neck shortening is a common complication after surgical treatment for intracapsular femoral neck fractures. This study investigated whether fully-threaded Headless Compression Screw (FTHCS) can be a more length-stable implant than partially-threaded cannulated screw (PTCS) in reducing femoral neck shortening. METHODS: A total of 50 patients with undisplaced femoral neck fractures (17 treated by internal fixation with three FTHCS, and 33 treated by three PTCS) from 2011 to 2014 were enrolled in this study. The radiography of the hips and medical records were reviewed for proximal femur geometry and complications. RESULTS: Significant shortening of the femoral neck length until union were noted in both group (FTHCS group: -2.5 mm, p = 0.045; PTCS group: -2.4 mm, p = 0.011). There was no significant difference in the length of femoral neck shortening between groups (p = 0.855). Age was the only significant risk factor for >5 mm of femoral neck shortening (p = 0.041). The femoral neck-shaft angle tended to reduce and become more varus in both groups (FTHCS: -2.7°, SD = 4.5, p = 0.028; PTCS: -5.0°, SD = 8.3, p = 0.002), but the differences between groups were nonsignificant (p = 0.577). The complication rates were similar between FTHCS and PTCS (17.6% and 21.2%, p > 0.999). CONCLUSION: The FTHCSs may be a substitute for PTCSs, but it cannot prevent femoral neck shortening and varus collapse after fracture fixation. Future studies should focus on how to preserve femoral neck length and hip function after femoral neck fractures.

Fast incorporation of primary amine group into polylactide surface for improving C2C12 cell proliferation using nitrogen-based atmospheric-pressure plasma jets.

In this article, we report the development of the fast incorporation of primary amine functional groups into a polylactide (PLA) surface using the post-discharge jet region of an atmospheric-pressure nitrogen-based dielectric barrier discharge (DBD). Plasma treatments were carried out in two sequential steps: (1) nitrogen with 0.1% oxygen addition, and (2) nitrogen with 5% ammonia addition. The analyses show that the concentration of N/C ratio, surface energy, contact angle, and surface roughness of the treated PLA surface can reach 19.1%, 70.5 mJ/m(2), 38° and 73.22 nm, respectively. In addition, the proposed two-step plasma treatment procedure can produce a PLA surface exhibiting almost the same C2C12 cell attachment and proliferation performance as that of the conventional gelatin coating method. Most importantly, the processing/preparation time is reduced from 13-15 h (gelatin coating method) to 5-15 min (two-step plasma treatment), which is very useful in practical applications.