Cr(VI) immobilization by FeS-coated alumina and silica: Effects of pH and surface coating density.

We investigated the feasibility of using FeS-coated alumina and silica for permeable reactive barrier (PRB) applications. By both coated materials, Cr(VI) was reduced to Cr(III), which was immobilized via surface complexation/precipitation at acidic pH, and bulk precipitation at neutral to basic pH. Both pH and surface coating density (the amount of FeS deposits per unit surface area of a supporting matrix) controlled Cr(VI) reduction capacity and [Cr,Fe](OH)3 composition. The reduction was higher at acidic pH due to lower passivation, as evidenced by the increased production of Fe(III) (oxyhydr)oxides over Fe(II)-Fe(III) phases. The coated alumina, despite the lower amount of FeS deposits than the coated silica, showed greater reduction capacities due to its higher surface coating density, which made Fe(III) closer together to favor Fe(III) (oxyhydr)oxide formation. Since Cr(III) was preferentially substituted for Fe(III) in Fe(III) (oxyhydr)oxides, lower pH and higher surface coating density led to lower Cr fractions in [Cr,Fe](OH)3 because of the increased production of Fe(III) (oxyhydr)oxides. Given that Cr-poor [Cr,Fe](OH)3 is more resistant to re-oxidation, FeS-coated alumina is better for PRB applications. This study reveals the significance of the surface coating density when evaluating the effectiveness of coated materials in redox-based treatments.

A Landslide Monitoring System for Natural Terrain in Korea: Development and Application in Hazard Evaluations.

This study describes the development of a landslide monitoring system for the purpose of reducing damages caused by landslides in natural terrain. The system was developed to analyze the effects of landslide-inducing rainfall and the behavior of slopes through 12 monitoring stations that are distributed across eight national parks in Korea. Several sensors and a data acquisition equipment to monitor landslide were installed in each station. The composition of the system and its operating program were designed to efficiently manage the sizeable amounts of real-time monitoring data that are collected from the various stations. To test the potential of the developed system for reliable landslide hazard evaluations, data measured over a five-year period by the two monitoring stations in Jirisan National Park were analyzed. Subsequently, the suction stress of the soil over the monitoring period was calculated by applying laboratory test result of the geotechnical and unsaturated soil properties in the analysis domain area. The infinite slope stability analysis combined with an effective stress concept based on the suction stress was applied to calculate the factor of safety. This method also enabled the temporal and quantitative evaluation of slope stability in natural terrain. In addition, based on the monitoring and slope stability analysis results, an analysis for the spatial classification of landslide hazards was conducted. The analysis results quantitatively and statistically demonstrated that 98% of historical landslide initiation areas were classified as high hazard levels.

Increased Range of Motion Is Important for Functional Outcome and Satisfaction After Total Knee Arthroplasty in Asian Patients.

BACKGROUND: Although range of motion (ROM) is considered as an important factor for good outcome after total knee arthroplasty (TKA), the association of the degree of ROM with functional outcome and patient satisfaction is debated. We, therefore, investigated whether increased ROM would affect functional outcome and patient satisfaction after TKA in Asian patients. METHODS: We reviewed 630 patients who underwent primary TKA with minimum 2-year follow-up. Clinical outcomes were evaluated by Knee Society (KS) score, Western Ontario and McMaster Universities osteoarthritis index, and high-flexion knee score. Patient satisfaction was evaluated using a validated questionnaire. The association of ROM and change in ROM (cROM) with clinical outcomes and satisfaction were analyzed using partial correlation analysis and multiple median regression analysis. RESULTS: All functional scores showed significant correlation with postoperative ROM (r = 0.129, P = .001 in Knee Society score; r = -0.101, P = .012 in Western Ontario and McMaster Universities osteoarthritis index; r = 0.183, P < .001 in high-flexion knee score). cROM correlated with satisfaction (r = 0.192, P = .005). Postoperative ROM and cROM were revealed as predisposing factors affecting function outcome using multivariable regression analysis. cROM was found as a predisposing factor affecting satisfaction. CONCLUSIONS: Based on the results of this study, ROM positively associated with functional outcome and cROM positively associated with patient satisfaction after TKA. These findings suggest that increased ROM after TKA is an important factor for functional outcome and satisfaction in Asian patients.

Are the Current Outcome Measurement Tools Appropriate for the Evaluation of the Knee Status in Deep Flexion Range?

We determined whether current outcome measurement tools are appropriate for the evaluation of the knee status in deep flexion range after TKA. Patients (n = 604) with more than 120° of knee flexion were evaluated by Knee Society score, WOMAC, and high flexion knee score (HFKS). The appropriateness of measurement tools was analyzed by correlation analyses and group comparisons (group 1: 120°-129°, group 2: 130°-139°, group 3: 140°-150°). HFKS showed stronger correlation with knee flexion compared with other scores. While other scores only differentiated between groups 2 and 3, HFKS could differentiate among groups 1, 2 and 3. These findings suggest that employment of proper outcome measurement tool is needed to evaluate and differentiate the knee status in deep flexion range after TKA.

The size of tibial footprint of anterior cruciate ligament and association with physical characteristics in Asian females.

INTRODUCTION: The tibial footprint is important for preoperative planning of operative technique and graft selection. Knowledge of tibial footprint in Asians is scant including the relationship between tibial footprint and physical characteristics. The aim of this study was to identify the size of the anterior cruciate ligament (ACL) tibial footprint and the proportion of size <14 mm, and to evaluate the association of tibial footprint with physical characteristics in Asian females. MATERIALS AND METHODS: A total of 127 patients with intact or minimal change in ACL were included. The tibial footprint was carefully measured during total knee arthroplasty. As potential predictors, leg length, femoral length, tibial length, and anteroposterior and mediolateral diameter of the proximal tibia were measured on radiographs, as well as body height and weight. The relationship of ACL tibial footprint length <14 mm with physical characteristics was analyzed using univariable and multivariable logistic regression. RESULTS: The tibial footprint was 13.8 mm (range 10.0-18.0) in length and 9.8 mm (range 6.3-13.5) in width. The proportion of footprints <14 mm in length was 53.5 %. Patient height, leg length, femoral length, and tibial length were correlated with tibial footprint. Tibial length was the best predictor of ACL tibial footprint length <14 mm (Odds ratio 1.75; 95 % confidence interval 1.08-2.82). CONCLUSIONS: Tibial footprint size shows a large variation with a high proportion of <14 mm length. Tibial length can help predict the ACL tibial footprint in the preoperative planning of ACL reconstruction.