Low-Friction Hybrid Hydrogel with Excellent Mechanical Properties for Simulating Articular Cartilage Movement.

Hydrogels, which can withstand large deformations and have stable chemical properties, are considered a potential material for cartilage repair. However, hydrogels still face some challenges regarding their mechanical properties, tribological behavior, and biocompatibility. Thus, we synthesized a hybrid hydrogel by means of chemical cross-linking and transesterification using glycerol ethoxylate (GE) and zwitterionic polysulfobetaine methacrylate (PSBMA) as raw materials. The hybrid hydrogel showed excellent compressive stress at approximately 3.50 MPa and low loss factors (0.023-0.049). Moreover, because GE has good water binding properties, helping to form a stable hydration layer and maintain low energy dissipation, a low friction coefficient (µ ≈ 0.028) was obtained with the "soft-soft contact mode" of a hydrogel hemisphere and hydrogel disc under reciprocating motion. In vitro cytotoxicity, skin sensitization, and irritation reaction tests were carried out to show good biocompatibility of the GE-PSBMA hybrid hydrogel. In this study, a hybrid hydrogel with no potential cytotoxicity, strong compressive capacity, and excellent lubricity was obtained to provide a potential alternative for developing polymer hybrids, as well as demonstrating an idea for the application of hybrid hydrogels in cartilage replacement.

An exploration of attitudes toward bystander cardiopulmonary resuscitation in university students in Tianjin, China: A survey.

BACKGROUND: Despite the importance of early effective bystander cardiopulmonary resuscitation (CPR) to improve survival rates from out-of-hospital cardiac arrest, the attitudes toward performing, learning and disseminating CPR in university students of China are still unclear. METHODS AND AIMS: To assess the attitudes regarding performing, learning and disseminating bystander CPR in university students of China. RESULTS: The results indicated that except for the scenario where the victim was their own family member or close friend, all other scenarios showed a relatively dismally lower rate of positive response. Besides, it showed a greater willingness to perform chest compression only CPR (CC) than chest compression with mouth-to-mouth ventilation (CCMV) (P < 0.05). Females were more willing to perform CC across seven of the hypothetic scenarios than males. University students of medical-related specialties (45.3%) than university students of non-medical specialties (29.9%) were more willing to perform bystander CPR (P < 0.05). The top four reasons for being unwilling to perform bystander CPR were lack of confidence (32.9%), fear of legal disputes (17.2%), fear of disease transmission (16.0%) and feeling embarrassed (14.0%). 92.6% of respondents wanted to learn CPR and 80.3% of respondents were willing to disseminate CPR. CONCLUSIONS: CPR technique, victim's status, respondent's specialty and respondent's gender affected the attitudes of respondents toward performing bystander CPR. The top four reasons for being unwilling to perform bystander CPR were lack of confidence, fear of legal disputes, fear of disease transmission and feeling embarrassed. However, the key reason for being unwilling to perform bystander CPR differed in different specialties and particularly 'feeling embarrassment' might be a cultural phenomenon. The attitudes toward learning and disseminating CPR were positive and affected by respondent's gender and specialty.