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Background: Unstable trochanteric femur fractures in elderly patients with osteoporosis are still challenging. Gamma3 nail with the U-blade lag screw (U-blade gamma nail) has been developed to improve mechanical stability of proximal femoral fragment. This study aimed to compare the clinical and radiologic outcomes of U-blade gamma nail to proximal femoral nail antirotation (PFNA), and standard Gamma3 nail (gamma nail) for unstable trochanteric femur fractures. Methods: A retrospective matched-pair case study was performed with U-blade gamma nail, PFNA, and gamma nail. During 2012-2018, 970 patients with unstable trochanteric femur fractures were reviewed. Matching criteria were set as follows: 1) sex; 2) age (± 3 years); 3) body mass index (± 2 kg/m2); 4) bone mineral density (± 1 T-score in femur neck). Finally, a total of 159 patients were enrolled. We assessed the tip-apex distance (TAD), neck shaft angle, and hip screw sliding distance using plain radiographs. Also, we evaluated the clinical outcomes with Koval’s grade and fixation failure during 2 years. Results: The mean postoperative TAD was not significantly different among the 3 groups (p = 0.519). However, the change in the TAD at 1 year (p = 0.027) and 2 years (p = 0.008) after surgery was significantly smaller in U-blade gamma nail group compared with PFNA and gamma nail group. The hip screw sliding distance at 1 year (p = 0.004) and 2 years (p = 0.001) after surgery was significantly smaller in U-blade gamma nail group compared with PFNA and gamma nail group. However, there was no significant difference of Koval’s grade and fixation failure among the 3 groups (p = 0.535). Conclusion: U-blade gamma nail showed favorable radiologic results in terms of the change in the hip screw position. However, U-blade gamma nail was not superior to PFNA and gamma nail in clinical outcomes.

The direct synthesis of hydrogen peroxide (DSHP) from H2 and O2 is conceptually the most ideal and straightforward reaction for producing H2O2 in industry. However, precisely tailored catalysts are...

An efficient method to enhance the catalytic properties of Zn-ferrite catalyst in the oxidative dehydrogenation of n-butene to 1,3-butadiene is proposed. The incorporation of phosphorous compound in Zn-ferrite is very effective to improve the catalytic activity as well as to maintain extremely long useful lives at high oxygen to n-butene ratio. It is found that the amount of phosphorous is critical and the presence of appropriate amount of phosphorous in catalyst may contribute the catalyst stabilization by which unfavorable reduction of Fe3+ sites to Fe2+ is effectively suppressed. This suggests that the oxygen mobility is maintained as high as the redox mechanism keeps constantly working. On the other hand, the effort to increase the population of mobile oxygen species by the introduction of external oxygen donor phase is found to be rather ineffective regardless of the external donor oxides used.

Two types of zinc ferrite catalysts have been prepared by physical mixing or coprecipitation and applied to the oxidative dehydrogenation of n-butene to 1,3-butadiene. It is observed that the catalytic activity is significantly dependent upon not only the crystallinity but also the composition of a ferrite catalyst. If crystallinity of a catalyst is too high, the oxygen spillover through the lattice is severely suppressed and results in low catalytic activity. On the other hand, the presence of α-Fe2O3 in ferrite structure may lead to decrease of the reaction performance. Coprecipitation with strong base such as NaOH is found to be one of the efficient methods to form a catalytically active ferrite structure in that it is advantageous to obtain pure ferrite composition with appropriate crystallinity. During catalyst preparation, complete removal of sodium is essential because the residual sodium in catalyst considerably reduces the reaction performance. Although the use of mild base such as NH4OH is advantageous to prevent the exhaustive washing, the formation of mixed phase both α-Fe2O3 and ZnFe2O4 may reduce n-butene conversion as well as 1,3-butadiene selectivity.

The light-off temperature of the oxidations of CO and C 3 H 6 over a commercial three-way catalyst (TWC) was shifted to a lower temperature by the addition of water to the feed stream. From FTIR analysis, the formation of carboxylate and carbonate by a reaction between adsorbed CO and OH on the catalyst surface was observed during the course of the reactions. In addition, the CO desorption peak of CO-TPD shifted to a lower temperature by water, which may be directly indicative of the reduction of the adsorption strength of CO on the catalyst surface. Detailed reaction kinetic models have been developed in view of the concept of microkinetics to describe the effect of water, particularly on the oxidation activity over a commercial TWC.

A detailed reaction kinetic model to predict the activity of the commercial three-way catalyst (TWC), particularly 4k miles aged catalyst in an engine dynamometer, has been developed by considering all possible reactions in the catalytic converter based upon the Langmuir–Hinshelwood mechanism. The model predictions adequately describe the general trend of the measured conversions of CO, C 3 H 6 , NO and H 2 . NH 3 and N 2 O formed during the reaction can also be predicted by the model. Moreover, the decrease in activity of the 100k miles aged catalyst can be well described by the model developed in the present study.

A Pd catalyst is particularly effective for the oxidation of CO and C3H6 at low temperatures, while the Pt/Rh/Ce catalyst is active for NO reduction. The TWC activity of both catalysts generally decreased as the catalyst mileage increased. However, the NO reduction activity was less affected by catalyst aging compared to the oxidation reactions. The selectivity of the catalysts in favor of the CO–O2 reaction (vs. C3H6–O2 reaction) in the O2 partitioning experiments became less pronounced as the catalyst aged. The NO partitioning experiments reveal the superior capability of H2 in NO reduction to the other reductants (CO and C3H6) examined in the present study. The reactivities of NO with both H2 and CO were found to decrease upon catalyst aging, resulting in decreased overall NO removal activity.

A highly efficient and industrially viable catalyst design for the direct synthesis of H(2)O(2) from H(2) and O(2) was realized by the encapsulation of Pd nanoparticles in polyelectrolyte multi-layers on a sulfonated resin. The continuous production of 9.9 wt% H(2)O(2) was achieved under intrinsically safe and non-corrosive conditions without any loss of activity.