Primary Total Hip Arthroplasty Using Summit® Stems in Korean: Minimum Four-year Follow-up.

PURPOSE: The aim of this study was to assess the mid-term results of primary cementless total hip arthroplasty (THA) using Summit® stems. MATERIALS AND METHODS: One hundred twenty-eight arthroplasties in 121 patients who were performed THA from December 2004 to March 2013, were reviewed retrospectively a minimum of 4 years follow-up (mean age, 60.3 years; mean postoperative follow up period, 86.3 months). For a clinical evaluation, the Harris hip score (HHS) was used to assess outcome. Radiographic evaluation was done through spot welds, subsidence, stress shielding, canal filling. RESULTS: The mean HHS was 69.8 points preoperatively, and it improved significantly to 96.3 points at the final follow-up. Postoperatively, 10 patients experienced thigh pain and 7 patients showed a moderate limping gait. There was not only early stem subsidence but there was no more subsidence at last follow up. One hundred eighteen hips showed radiographic signs of stem bone ingrowth, and 10 hips showed fibrous ingrowth at the last follow-up. Stress shielding occurred in 85 hips and third degree stress shielding was observed in 6 hips. Complication arose in 10 hips due to dislocation. Although revisions due to recurrent dislocations led to acetabular component revision in one hip, no revisions arose due to isolated aseptic loosening of the femoral component. CONCLUSION: The clinical and radiological mid-term results of primary THA using Summit® stems revealed solid initial fixation and bone ingrowth stable fixation. Considering the satisfactory clinical results, Summit® stems may be a good treatment option in Korean patients who were required hip arthroplasty.

Mid-Term Outcomes of Anterior Cruciate Ligament Reconstruction with Far Anteromedial Portal Technique.

PURPOSE: The purpose of this study was to evaluate the mid-term outcomes of anatomic anterior cruciate ligament (ACL) reconstruction using two anteromedial (AM) portals by comparing with short-term follow-up results. MATERIALS AND METHODS: Fifty patients who were treated by ACL reconstruction using a two AM portal technique were evaluated retrospectively. The follow-up period was at least 5 years. The mean follow-up period was 68.5±13.9 months. The mid-term clinical outcomes were compared with short-term (≥12 months) results. For the assessment of knee stability, anterior tibial translation was evaluated using the Lachman test and the KT-2000. Rotational stability was evaluated using pivot shift test. For clinical assessment, the Lysholm and International Knee Documentation Committee scores were used. RESULTS: The average anterior translation was 2.1±1.4 mm at the short-term follow-up and 2.8±1.8 mm at the mid-term follow-up. Stability and mid-term clinical outcomes were not significantly improved compared to the short-term follow-up results. At the mid-term follow-up, anteroposterior (AP) instability assessed by the KT-2000 was slightly increased, but still acceptable. On the other clinical physical evaluation, there was no statistically significant difference. CONCLUSIONS: The short-term and mid-term outcomes of ACL reconstruction using the two AM portal technique were not significantly different except for AP stability although the value was less than 3 mm at both follow-ups. Therefore, this operative technique could be considered a satisfactory alternative for ACL reconstruction.

Crystallographic Wet Chemical Etching of Semipolar GaN (11-22) Grown on m-Plane Sapphire Substrates.

This paper reports the etch rates and etched surface morphology of semipolar GaN using a potassium hydroxide (KOH) solution. Semipolar (11-22) GaN could be etched easily using a KOH solution and the etch rate was higher than that of Ga-polar c-plane GaN (0001). The etch rate was anisotropic and the highest etch rate was measured to be approximately 116 nm/min for the (1011) plane and 62 nm/min for the (11-20) plane GaN using a 4 M KOH solution at 100 °C, resulting in specific surface features, such as inclined trigonal cells.

Low-ppm-Level colorimetric acid detection using gold nanoparticles with electro-steric stabilization.

Electro-sterically stabilized gold suspensions were employed in a colorimetric system for the detection of strong acid in water. Using oleyamine and oleic acid as steric stabilizer in 1,2-dichlorobenzene, hydrophobic gold nanoparticles were first synthesized by a reduction reaction of gold salts and were then transferred into water with a cationic surfactant. When the hydrochlo- ric acid solution higher than critical concentration was injected, particles were quickly aggregated and precipitated, creating a clear solution from the colored suspension. The particles were stable against chemical etching by corrosive ion such as chloride. Critical concentration was dependent of the size and concentration of the particles. The minimum concentration of dramatic color change was at 5 ppm level of hydrochloric acid, in which the largest colloidal gold nanoparticles (54 nm) were used. Furthermore, because of their steric repulsive soft layer on particles, particles could be reused for further detection experiments after regeneration by the simple pH-neutralization and washing process.

Room temperature deposition of silicon nanodot clusters by plasma-enhanced chemical vapor deposition.

The formation of nanometer-scale (ns)-Si dots and clusters on p-GaN layers has been studied by controlling the early stage of growth during plasma-enhanced chemical vapor deposition (PECVD) at room temperature. We found that ns-Si dots and clusters formed on the p-GaN surface, indicating that growth was the Volmer-Weber mode. The deposition parameters such as radio frequency (RF) power and processing time mainly influenced the size of the ns-Si dots (40 nm-160 nm) and the density of the ns-Si dot clusters.

Characteristics of the Ni-B film in printed circuit board for high-power light-emitting diodes.

To develop metal printed circuit boards for a high-power light-emitting diode package using electroless plated Ni-B films on an all-in-one Al2O3-Al substrate with a 10 nm pore size, the growth mode of an electroless Ni-B film on a screen-printed Ag pattern/Al2O3-Al substrate was studied. So as not to damage the Al2O3-AI substrate, a nearly neutral Ni plating solution bath (pH 6.5) included dimethylamine borane was used. It was confirmed that the Ni-B film was selectively grown on the printed Ag paste layer, without growth on the Al2O3. The structure of the electroless plated Ni-B film was amorphous, and the deposition rate of the film was 1.64 +/- 0.078 nm/sec. According to the increase in plating time, the grain sizes of the electroless plated Ni-B film became bigger, and the surface morphology gradually became flatter. In addition, both the mass difference and the film thickness were changed linearly. From these results, it can be concluded that the electroless Ni-B film on printed Ag paste grows immediately from the beginning, and then grows linearly with increasing plating time.

Ohmic contacts to N-face p-GaN using Ni/Au for the fabrication of polarization inverted light-emitting diodes.

The electrical properties of Ni-based ohmic contacts to N-face p-type GaN were investigated. The specific contact resistance of N-face p-GaN exhibits a linear decrease from 1.01 omega cm2 to 9.05 x 10(-3) omega cm2 for the as-deposited and the annealed Ni/Au contacts, respectively, with increasing annealing temperature. However, the specific contact resistance could be decreased down to 1.03 x 10(-4) omega cm2 by means of surface treatment using an alcohol-based (NH4)2S solution. The depth profile data measured from the intensity of O1s peak in the X-ray photoemission spectra showed that the alcohol-based (NH4)2S treatment was effective in removing the surface oxide layer of GaN.