Optimization of tungsten dual poly-metal gates in memory devices with Ti/Wn/WSiN barrier metal.

Due to the demand of high-speed/high-density and low power application of memory devices, tungsten dual poly gate (W-DPG; W/barrier metals/n+ and p+ poly-Si) electrode could be a good solution in order to reduce gate sheet resistance (Rs). Process optimization is completed for a diffusion barrier metal in a W-DPG. A new noble WSiN layer is inserted between the Ti/WN barrier metal and the tungsten gate electrode to maintain large grain size of W deposited by physical vapor deposition. The annealed WSiN during post-processing changes into crystallized WSi(x) mixed with SiN, which can make vertical conductive path between top and bottom interface, contributing to low vertical contact resistance (Rc) and low gate Rs adequate for high speed requirement of memory device. The Ti/WN/WSiN barrier is found to have the same electrical performance, ring oscillator singal delay as complicated multi-layes barrier metal, Ti/WN/TiN/WSi(x)/WN reported earlier. Therefore, the gate stack can be optimized by introducing a simpler diffusion barrier metal.

Independent associations of circulating 25-hydroxyvitamin D and parathyroid hormone concentrations with blood pressure among Koreans: The Korea National Health and Nutrition Examination Survey (KNHANES), 2009-2010.

Although lower vitamin D and higher parathyroid hormone (PTH) concentrations have been associated with hypertension, their independent contribution to blood pressure (BP) is unclear. The independent associations of serum 25-hydroxyvitamin D (25[OH]D) and PTH levels with BP were therefore investigated. This is a population-based cross-sectional study from the Korea National Health and Nutrition Examination Surveys, which includes a total of 4,513 participants (2,019 men and 2,494 women) aged ≥ 50 years. 25(OH)D and PTH were measured by radioimmunoassays, and BP was determined with a sphygmomanometer. Hypertensive subjects had significantly lower 25(OH)D (p = 0.023) and significantly higher PTH (p < 0.001) concentrations than normotensives. In subjects not taking antihypertensive medications, 25(OH)D showed reverse correlations with systolic and diastolic BP, both in men (p = 0.038-0.061 and p = 0.011-0.038, respectively) and in women (p = 0.006-0.018 and p = 0.001-0.011, respectively), while serum PTH concentrations showed positive correlations with systolic and diastolic BP in men (p = 0.001-0.014 and p < 0.001, respectively) and women (p < 0.001-0.008 and p = 0.001-0.040, respectively). When 25(OH)D and PTH were included in the same model, both remained independently associated with BP in men and women. In conclusion, both lower 25(OH)D and higher PTH may be independent factors for the development of hypertension.

Osteonecrosis of femoral head treated with alendronate in a 14-year-old boy: a case report.

We describe a 14-year-old adolescent with osteonecrosis of femoral head, who was treated successfully with oral bisphosphonate. To prevent physeal damage by surgical treatment, alendronate was administered weekly for 20 months. A complete resolution was achieved. This report suggests that bisphosphonate may be an effective nonoperative treatment for osteonecrosis of femoral head.

Treatment of periprosthetic femoral fractures in hip arthroplasty.

BACKGROUND: We analyzed the radiological and clinical results of our study subjects according to the management algorithm of the Vancouver classification system for the treatment of periprosthetic femoral fractures in hip arthroplasty. METHODS: We retrospectively reviewed 18 hips with postoperative periprosthetic femoral fractures. The average follow-up was 49 months. The fracture type was determined based on the Vancouver classification system. The management algorithm of the Vancouver classification system was generally applied, but it was modified in some cases according to the surgeon's decision. At the final follow-up, we assessed the radiological results using Beals and Tower's criteria. The functional results were also evaluated by calculating the Harris hip scores. RESULTS: Seventeen of 18 cases (94.4%) achieved primary union at an average of 25.5 weeks. The mean Harris hip score was 92. There was 1 case of nonunion, which was a type C fracture after cemented total hip arthroplasty, and this required a strut allograft. Subsidence was noted in 1 case, but the fracture was united despite the subsidence. There was no other complication. CONCLUSIONS: Although we somewhat veered out of the management algorithm of the Vancouver classification system, the customized treatment, with considering the stability of the femoral stem and the configuration of the fracture, showed favorable overall results.

Hemicallotasis for correction of varus deformity of the proximal tibia using a unilateral external fixator.

BACKGROUND: Gradual correction of varus deformity of the proximal tibia is generally accepted and produces good results. However, most studies have used circular external fixators, which are complex and cause patient discomfort. This study was undertaken to determine the efficacy of hemicallotasis with a unilateral external fixator for correction of varus deformity of the proximal tibia. METHODS: Thirteen patients (21 legs, 8 bilateral) were included in this study: 6 with constitutional bowing, 3 with a malunion, 2 with Blount's disease, and 2 with Turner syndrome. There were 7 males and 6 females of mean age 21 years (range 13-40). With an oblique osteotomy on the proximal tibia, a unilateral external fixator was placed on the medial side. Using a distraction of 1 mm/day, the external fixator was removed after consolidation of the callus. RESULTS: Surgery corrected medial proximal tibia angle from a preoperative average of 75.1° (64°-81°) to 88.6° (86°-90°) at final follow-up. Average tibiofemoral angle improved from -7° to 6.8°. The duration of external fixation averaged 101.3 days and the external fixation index was 70 days/cm. No patient had a limited ambulation, and all recovered preoperative range of knee motion (mean 130.1°) at final follow-up. Seven minor complications (pin tract infection, clamp loosening) and 1 major complication (uncorrected genu procurvatum) were observed. CONCLUSIONS: Hemicallotasis using a unilateral external fixator was found to be a safe and simple corrective procedure for varus deformity of the proximal tibia, with few complications.

A biomechanical analysis of locking plate fixation with minimally invasive plate osteosynthesis in a subtrochanteric fracture model.

OBJECTIVE: The objective of this study was to establish the relative fixation strengths of a locking plate, a dynamic condylar screw (DCS) plate, and a long proximal femoral nail (PFN). METHODS: The study involved three groups of composite large femoral synthetic bones of five specimens per group; plating using a locking compression plate-distal femur (LCP-DF), plating using a DCS plate, and nailing using a long PFN. A gap osteotomy model was used to simulate a comminuted subtrochanteric femur fracture. For each femur, a minimal preload of 100 N was applied before loading to failure. A vertical load was applied at 10 mm/min until femur failure. Load to failure, mode of failure, and displacement at load to failure were documented. RESULTS: Fixation strength (load or moment to failure) of LCP-DF (1,330 N; range, 1,217-1,460 N) was 26.6% and was greater in axial loading compared with DCS (1050.5 N; range, 956.4-1194.5 N) and 250% less in axial loading compared with long PFN (3633.1 N; range, 3337.2-4020.4 N; p=0.002). Ultimate displacement in axial loading was similar for LCP-DF (18.4 mm; standard deviation [SD], 1.44), DCS (18.3 mm; SD, 3.25), and long PFN (16.7 mm; SD, 1.82). CONCLUSIONS: The LCP-DF construct proved stronger than the DCS in terms of ultimate strength by biomechanical testing of a simulated subtrochanteric femur fracture with comminution. Although the nail construct proved strongest, the biomechanical performance of the locking plate construct may lend credence to the use of a locking plate versus the DCS plate for minimally invasive plate osteosynthesis of subtrochanteric femur fractures, which may be technically difficult to fix using a nail.