Hybrid materials for meniscus replacement in the knee

The meniscus is cartilage that not only prevents the bones in knee joints to grind together but acts as a joint stabiliser. Many athletes and older people suffer from meniscus tears and degeneration. Meniscal tear treatments have been through meniscal suture or by partial meniscectomy (removal). These treatments may cause changes in loading or decreased contact area and increased contact stress. Consequently, the ultimate result is a total meniscectomy that potentially leads to osteoarthritis (OA). These current surgical strategies have lower success rates in younger patients. There are no successful artificial meniscus replacement devices for young patients, therefore, new materials for meniscus replacement are required. Here, the aim was to develop a novel biomimetic meniscus device made of a silica/polytetrahydrofuran (SiO2/polyTHF) inorganic/organic hybrid material. The device is biomimetic in terms of its structural design, mechanical properties, and integration with the host tissue. The device should delay onset of OA. The hybrid has unique properties in that is a bouncy material which has comparable mechanical properties to knee cartilage. Two pot hybrid synthesis was used to synthesise the SiO2/polyTHF hybrid and casting mould was developed based on the shrinkage factor of the hybrid. The hybrid synthesis modifications were conducted by controlling compositions and drying processes. Biological fixation of the hybrid meniscus was achieved by titanium anchors with gyroid porous architecture which can provide initial mechanical fixation and secondary biological fixation on the tibia. The architecture was designed using Solidworks and Rhinoceros software and printed by the Additive Manufacturing technique of selective laser melting (SLM). Mechanical testing of the device included compression, cyclic loading, shear strength and long-term 90 days in-vitro mechanical testing, tribology against living bovine 2 cartilage, and cell studies. The results suggest that combination of hybrid and Ti gyroid has potential to be meniscus implant due to comparable mechanical properties, low friction coefficient, and non-cytotoxicity.Open Acces

A MULTI-METHOD DESIGN TO INVESTIGATE THE ROLES OF READING STRATEGY USE AND READING INTEREST IN COMPREHENSION OF ENGLISH EXPOSITORY TEXTS FOR EIGHTH GRADERS IN THE EFL CONTEXT

This study aimed to address three research gaps revealed in previous studies on L2 reading comprehension and L2 reading strategy use: (a) a restricted use of methodology in assessing L2 reading strategies, (b) inadequate attention to the role of reading interest in L2 reading comprehension, and (c) a lack of comprehensive understanding about the relationships between reading strategy use and reading interest in L2 reading. A multi-method design was adapted to assess L2 reading strategy use and L2 reading interest. The assessment methods for strategy use included think-aloud protocols and a L2 reading strategy questionnaire, the Cognitive-Metacognitive Strategy Questionnaire. To quantify the data from the think-aloud protocols, three scoring procedures were developed based on the frequency counts of the strategy coding system: (1) Quantity of Total Strategy Use, (2) Quality of Total Strategy Use and (3) Sophistication of Strategy Use. In addition, the readers' reading interest was measured by semi-structural interviews and two interest scales: the Situational Interest Questionnaire and the Interest Experience Scale. Based on the multiple assessments with 36 participants, the study examined (1) the specific L2 reading strategies employed by eighth graders in Taiwan and how the results from different strategy assessments corresponded to each other, (2) the sources for L2 reading interest for the eighth graders, and (3) how L2 reading strategy use and reading interest interacted with each other to influence L2 reading comprehension. The results indicated that the L2 readers utilized three clusters of reading strategies during comprehension: (1) textbase comprehension strategies, such as translation and paraphrasing, (2) situation model construction strategies, such as elaboration, summarization and drawing inferences, and (3) metacognitive monitoring strategies. The study also found that the measure, Sophistication of Strategy Use, had the most satisfactory validity among the strategy measures. The degree of sophistication in strategy use was more associated with the readers' text recalls than the quantity of total strategy use, indicating how the readers intentionally and carefully processed each strategy played a significant role to improve reading comprehension. Moreover, the study found several content characteristics which had positive influences on L2 readers' interest in the text; they were relevance, importance, novelty and familiarity of the ideas contained in the text. Furthermore, the case analyses on three readers' profiles showed that reading interest was closely related to the depth of the readers' strategic engagement. The less proficient L2 reader, Alice, possessed high reading interest and demonstrated an attempt to employ more higher-order, situation model construction strategies during reading. By contrast, the proficient L2 reader, Stella, did not intend to comprehend the text in depth and utilized the strategies at the superficial level due to low reading interest. These findings presented a dynamic picture of the intertwined relationship between strategy use and reading interest in L2 reading comprehension

Implementation of reinforcement learning in game strategy design

The purpose of this study is to apply reinforcement learning to the design of game strategy. In the gaming industry, the strategy used by computers to win a game is usually pre-programmed by game designers according to the game patterns or a set of rules