To investigate the effects of meniscectomy on degenerative osteoarthritis, a three-dimensional (3D) finite element (FE) model of the human lower limb is constructed from a combination of magnetic resonance (MR) images and computed tomographic (CT) images that can provide anatomically suitable boundary conditions for a knee joint. Four cases, i.e., the intact meniscus, and the partial, sub-total, and total meniscectomy of the medial meniscus are modeled and simulated. We consider that the cartilage-to-cartilage contact area and the peak contact pressure in the meniscus may be significant parameters in evaluating degenerative osteoarthritis. Partial meniscectomy can be regarded as a better treatment than sub-total/total meniscectomy, and a high possibility of degenerative osteoarthritis is anticipated after total meniscectomy. Moreover, medial meniscectomy has the potential to bring about degenerative osteoarthritis in both the medial compartment and the lateral compartment of a knee joint.

The anatomic transtibial (TT) technique is proposed as a new approach for single-bundle anterior cruciate ligament (ACL) reconstruction. Geometric models of the anatomic TT and anteromedial (AM) portal techniques were fabricated with a reconstructed knee joint model and virtual surgical operations. Grafts of 7 mm diameter were modeled and inserted into tunnels drilled in each model. In the models, the shape of the graft between the femur and the tibia, the lengths of the bone tunnels, and the femoral graft bending angles were evaluated. To evaluate the biomechanical effects of both techniques on the grafts, the contact pressures and maximum principal stresses in the grafts were calculated using the finite element method. The anatomic TT technique placed the femoral tunnel to the anatomic position of the native ACL femoral attachment site. In addition, it decreased the peak contact pressure and the maximum principal stress at the full extension position of the graft compared with the AM portal technique. The anatomic TT technique may be regarded as a superior surgical technique compared with the conventional TT and AM portal techniques. Because of the easy surgical operation involved, the technique decreases the operation time for ACL reconstruction and it provides a deformation behavior of grafts similar to that in the native ACL in a knee joint. With its few side effects, the anatomic TT technique may considerably help patients.

High-resolution fluorescence techniques that provide spatial resolution below the diffraction limit are attractive new methods for structural characterization of nanostructured materials. For the first time, we apply the super-resolution technique of Stochastic Optical Reconstruction Microscopy (STORM), to characterize nanoscale structures within polymer blend films. The STORM technique involves temporally separating the fluorescence signals from individual labeled polymers, allowing their positions to be localized with high accuracy, yielding a high-resolution composite image of the material. Here, we describe the application of the technique to demixed blend films of polystyrene (PS) and poly(methyl methacrylate) (PMMA), and find that STORM provides comparable structural characteristics as those determined by Atomic Force Microscopy (AFM) and scanning electron microscopy (SEM), but with all of the advantages of a far-field optical technique.

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We used finite element (FE) method to investigate the effect of the drilling number and entry location of holes used in the multiple drilling technique on the stress and strain state in femur. Different three-dimensional FE models of a human hip joint with or without multiple drilling were fabricated using computed tomographic images obtained from the hip joint of a cadaver. The analysis technique was evaluated in a compression test using the cadaver specimen and FE analysis for the test using an FE model of the specimen. Von Mises stresses, principal stresses, and principal strains in the cancellous and cortical bone were calculated by using the different models, and changes in these values in relation to drilling number and entry hole locations were evaluated. Calculated peak values were much smaller than the yield strength, tensile strength, and yield strain of the cancellous and cortical bone for all cases of multiple drilling. Our results support that the multiple drilling technique for osteonecrosis of the femoral head is a stable operation technique.

To show the causal relationship between normal walking after various lateral ankle ligament (LAL) injuries caused by acute inversion ankle sprains and alterations in ankle joint contact characteristics, finite element simulations of normal walking were carried out using an intact ankle joint model and LAL injury models. A walking experiment using a volunteer with a normal ankle joint was performed to obtain the boundary conditions for the simulations and to support the appropriateness of the simulation results. Contact pressure and strain on the talus articular cartilage and anteroposterior and mediolateral translations of the talus were calculated. Ankles with ruptured anterior talofibular ligaments (ATFLs) had a higher likelihood of experiencing increased ankle joint contact pressures, strains and translations than ATFL-deficient ankles. In particular, ankles with ruptured ATFL + calcaneofibular ligaments and all ruptured ankles had a similar likelihood as the ATFL-ruptured ankles. The push off stance phase was the most likely situation for increased ankle joint contact pressures, strains and translations in LAL-injured ankles.

The Covid-19 pandemic has shocked the global energy system. It has resulted in tremendous uncertainty and diminished the recent advances to increase access to affordable, reliable, sustainable and modern energy-an objective preserved in the UN Sustainable Development Goal 7 (SDG-7). According to the IEA, attaining universal electricity access in Africa in line with SDG-7 entails annual investments of approximately $20 billion over the next decade. Given the sizeable magnitudes involved, it is inevitable that energy projects will need to rely on richer nations for energy aid. This paper explores the linkages between energy-related external aid, carbon emissions, per capita GDP, and electricity access for a sample of 30 lowincome SSA countries over 1995 to 2016. Our econometric analysis reveals that while all types of energy aid facilitate economic growth in the long run, there is no direct impact of energy-related aid on electricity access. However, an increase in per capita GDP is positively associated with electricity access in both rural and urban areas. We also find that energy-related aid helps mitigate carbon emissions as well as contribute to GDP. Taken together, our results suggest that enhanced energyrelated aid to low-income SSA countries can directly facilitate climate compatible growth and indirectly impel improvements in electricity access thereby helping with poverty reduction. We also advocate regional cooperation among SSA countries as a collective effort to confront shared energy challenges.

To investigate the biomechanical effect of collars, finite element analyses are carried out through two hip joints that are implanted using collared and collarless stems, respectively, and an intact hip joint model. For the analyses, the sacrum, coxal bone, and the cancellous and cortical bones of a femur are modelled using finite elements based on X-ray computed tomographic images taken from a 27-year-old woman. From the results, it is found that a collar with perfect calcar contact prevents stem subsidence and decreases the proximal-lateral gap and the lateral stem tilting. Therefore, it can impart reasonable biomechanical stability for total hip arthroplasty. However, its low load transmission ability and increased stem tilting effect due to the imperfect contact between the collar and the calcar are found to be serious problems that need to be solved. Results of clinical follow-up are presented for supporting the computational results.