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Wearable technologies and flexible electronics have developed rapidly owing to the emergence of cutting-edge cross-disciplines. The flexibility and tunable properties of organic materials enable wearable sensory systems to adapt to complex surface deformations and detect physiological signals sensitively. The demand for high-performance strain sensors, to accurately detect complex movements and environmental changes, in wearable technology has increased notably. However, current sensors primarily detect strain in a single direction, which restricts their effectiveness in detecting multi-directional strains, such as in natural human movements or robotic joints. In this review, we examine the advances and future challenges that may arise in the development of strain sensors that can measure both the magnitude and direction of external tensile strain. Additionally, we examine the sensor materials (platform and sensing materials) required to develop a strain sensor to detect the direction of tension, structural research on strain sensors, and various application fields such as human motion detection and human–machine interaction via system integration. Finally, we discuss the prospects and current challenges involved in the development of direction-selective strain sensors for wearable smart electronic systems or electronic skin. This review should provide a comprehensive reference for future technologies. [ABSTRACT FROM AUTHOR]

Background: Numerous studies have explored factors impacting osteoarthritis (OA), but its relationship with height remains uncertain. This study investigates the relationship between height and osteoarthritis risk in South Korea. Methods: Participants aged 50 or older who underwent health screenings in 2009 were selected from the National Health Insurance System database. A total of 1,138,904 subjects were divided into height quartiles (Q1–Q4) based on age and gender. Cox proportional hazard models were used to assess knee osteoarthritis incidence risk, with the shortest quartile (Q1) as the reference. Results: After adjusting for age, sex, income, smoking, drinking, exercise, hypertension, diabetes mellitus, dyslipidemia, and body mass index (BMI), no significant difference in OA incidence risk based on height was observed. However, when adjusted for weight instead of BMI, we observed a gradual decrease in hazard ratio with increasing height. The hazard ratio for the tallest group was 0.787 (95% CI, 0.781~0.795). Similar results were obtained in all subgroups. Conclusions: Compared to previous studies, our findings present a clear distinction. Therefore, there may be racial differences in the association between height and knee OA risk, and our study provides evidence that, in East Asian populations, taller individuals have a reduced risk of knee OA. [ABSTRACT FROM AUTHOR]

Neuromorphic engineering has emerged as a promising research field that can enable efficient and sophisticated signal transmission by mimicking the biological nervous system. This paper presents an artificial nervous system capable of facile self‐regulation via multiplexed complementary signals. Based on the tunable nature of the Schottky barrier of a complementary signal integration circuit, a pair of complementary signals is successfully integrated to realize efficient signal transmission. As a proof of concept, a feedback‐based blood glucose level control system is constructed by incorporating a glucose/insulin sensor, a complementary signal integration circuit, an artificial synapse, and an artificial neuron circuit. Certain amounts of glucose and insulin in the initial state are detected by each sensor and reflected as positive and negative amplitudes of the multiplexed presynaptic pulses, respectively. Subsequently, the pulses are converted to postsynaptic current, which triggered the injection of glucose or insulin in a way that confined the glucose level to a desirable range. The proposed artificial nervous system demonstrates the notable potential of practical advances in complementary control engineering. [ABSTRACT FROM AUTHOR]

This study systematically investigates a capacitive sensor applied with phenol blue (PhB)‐based sensing medium for detection of L‐lactic acid (LA), as a health monitoring indicator. PhB is a substance with solvatochromic effect, inducing the change in capacitance by exposure to polar molecules. However, the capacitive LA sensor with a flat‐structured PhB/polyvinylchloride (PVC) composite‐sensing medium is observed to have a problem in that sensing capacitance variation saturate quickly with increasing the LA solution concentration. This main cause can be analyzed that the interaction of proton from LA molecule with the lone pair electrons of the PhB molecule acts as a major factor on the sensing characteristics rather than the solvatochromic behavior of PhB molecule. Therefore, a strategy is adopted to introduce a porous structure to the PhB/PVC composite‐sensing medium to maximize the interaction of PhB with protons, which is implemented through solvent and non‐solvent exchange methods. Consequently, the sensitivity and linearity of the porous‐structured LA sensor are 2.99 pF mm−1 and 0.966 over LA concentrations ranging from 0 to 100 mm, respectively, which is a significant improvement over that of the flat‐structured one. Notably, the sensing performance remained unchanged even after a month of storage under normal ambient conditions. [ABSTRACT FROM AUTHOR]

Background: Total knee arthroplasty (TKA) using a cemented technique has been recommended in patients with rheumatoid arthritis owing to the initial stability of the fixation and long-term durability of the components; however, similar long-term follow-up results have been reported in patients who have undergone cementless TKA. The purpose of this study was to evaluate the radiologic and clinical outcomes of cementless TKA in patients with rheumatoid arthritis. Methods: We enrolled patients undergoing cementless TKA from March 1990 to February 2000. Clinical and radiologic evaluations were performed using the Knee Society clinical rating system and radiographic evaluation and scoring system. Results: We included the cases of 112 patients who underwent 179 cementless TKA procedures in our analysis. Their mean age was 62.3 years, and the mean follow-up period was 10.1 years. The final survival rate was 0.968 at the 15.5-year follow-up. Regarding radiologic results after surgery, the mean total valgus angle was 6.7[degrees], the mean femoral flexion angle was 97.5[degrees] and the mean tibial angle was 89.2[degrees] on the anteroposterior radiographs. On the lateral films, the mean femoral flexion angle was 1.6[degrees] and the mean tibial angle was 89.2[degrees]. At the last follow-up, the mean total valgus angle was 6.5[degrees], the mean femoral flexion angle was 97.4[degrees] and the mean tibial angle was 89.1[degrees], as seen on the anteroposterior view. On the lateral views, the mean femoral flexion angle was 1.4[degrees] and the mean tibial angle was 89.0[degrees]. Regarding the clinical outcome, the mean knee score and function score on the Knee Society clinical rating system were also enhanced from 47.5 and 43.6, respectively, before the operation to 91.2 and 82.3, respectively, at the last follow-up. Conclusion: On radiologic and clinical follow-up of cementless TKA for patients with rheumatoid arthritis, there were no serious complications, and the results of the operation were satisfactory with improvement in range of motion and clinical symptoms. Contexte: On a recommande l'arthroplastie totale du genou (ATG) fixee par ciment orthopedique chez les patients souffrant de polyarthrite rhumatoide, en raison de la stabilite initiale de la fixation et de la longue durabilite des composantes. Or, des resultats similaires ont ete enregistres au suivi a long terme chez des patients qui ont subi une ATG non cimentee. Cette etude avait pour but d'evaluer l'issue radiologique et clinique de l'ATG non cimentee chez des patients souffrant de polyarthrite rhumatoide. Methodes: Nous avons recrute des patients soumis a une ATG entre mars 1990 et fevrier 2000 et procede a des examens cliniques et radiologiques appuyes sur les systemes d'evaluation clinique et radiographique et de notation de la Knee Society des Etats-Unis. Resultats: Nous avons inclus dans notre analyse 112 patients totalisant 179 interventions pour ATG non cimentee. Leur age moyen etait de 62,3 ans et le suivi a dure en moyenne 10,1 ans. Le taux final de survie etait de 0,968 au suivi a 15,5 ans. Pour ce qui est des resultats radiologiques apres la chirurgie, l'angle valgus total moyen etait de 6,7[degrees], l'angle de flexion femorale moyen, de 97,5[degrees] et l'angle tibial moyen, de 89,2[degrees], aux radiographies anteroposterieures. Sur les cliches lateraux, l'angle de flexion femorale moyen etait de 1,6[degrees] et l'angle tibial moyen, de 89,2[degrees]. Au dernier suivi, l'angle valgus total moyen etait de 6,5[degrees], l'angle de flexion femorale moyen, de 97,4[degrees] et l'angle tibial moyen, de 89,1[degrees], observes aux cliches anteroposterieurs. Aux cliches lateraux, l'angle de flexion femorale moyen etait de 1,4[degrees] et l'angle tibial moyen, de 89,0[degrees]. En ce qui a trait aux resultats cliniques, le score moyen global pour le genou et le score fonctionnel selon le systeme d'evaluation clinique de la Knee Society etaient aussi ameliores, passant de 47,5 et 43,6 respectivement, avant l'intervention, a 91,2 et 82,3 respectivement, au moment du dernier suivi. Conclusion : Le suivi radiologique et clinique des ATG non cimentees chez des patients souffrant de polyarthrite rhumatoide n'a revele aucune complication grave et les resultats de l'intervention ont ete satisfaisants, avec des ameliorations de l'amplitude de mouvement et des symptomes cliniques., Rheumatoid arthritis is an autoimmune inflammatory disease that is progressive and shows systemic manifestations. The course of rheumatoid arthritis varies greatly from mild, even self-limiting disease, to a severe, destructive [...]