Synergy of S-vacancy and heterostructure in BiOCl/Bi2S3-x boosting room-temperature NO2 sensing.

The special physicochemical properties of Bi2S3 nanomaterial endow it to be exceptional NO2 sensing properties. However, sensors based on pure Bi2S3 cannot detect trace NO2 at room temperature effectively due to the scanty active sites and poor charge transfer efficiency. Herein, vacancy defect and heterostructure engineering are rationally integrated to explore BiOCl/Bi2S3-x heterostructure with rich S vacancies to enhance NO2 sensing performance. The optimized sensor based on S-vacancy-rich BiOCl/Bi2S3-x heterostructure exhibited a high response value (Rg/Ra = 29.1) to 1 ppm NO2 at room temperature, which was about 17 times compared to the pristine Bi2S3. Meanwhile, the BiOCl/Bi2S3-x sensor also exhibited a short response time (36 s) towards 1 ppm NO2 and a low theoretical detection limit (2 ppb). The superior response value of S-vacancy-rich BiOCl/Bi2S3-x heterostructures was ascribed to the improved electron migration at the heterointerface and the additional exposed active sites caused by the S vacancies in Bi2S3-x. Additionally, the sensors based on S-vacancy-rich BiOCl/Bi2S3-x heterostructures showed good long-term stability, outstanding selectivity, and good flexibility. This study offers an effective method for synergistically engineering defect and heterostructure to enhance gas sensing properties at room temperature.

[Effectiveness of preoperative autologous plateletpheresis combined with intraoperative autotransfusion on the blood coagulation in orthopaedic patients].

OBJECTIVE: To investigate the effectiveness of preoperative plateletpheresis combined with intraoperative autotransfusion on the blood coagulation of orthopaedic patients. METHODS: Sixty patients (ASA I-II) undergoing selective orthopaedic surgery were randomized into three groups (n = 20), that is, preoperative plateletpheresis combined with intraoperative autotransfusion for group I, intraoperative autotransfusion for group II, and group III without any managements of blood conservation. Coagulation parameters (prothrombin time, partial thromboplastin time, fibrinogen), hemoglobin and hematocrit values, platelet counts and aggregability were evaluated before the anaesthesia, 10 minutes after plateletpheresis, 10 minutes before the infusion of platelet rich plasma or autologous blood, 10 minutes after infusion, 24 and 48 hours postoperation. Intra- and postoperation blood loss and homologous blood transfusion requirements were also recorded. RESULTS: Among three groups, there were no differences in intraoperative blood loss, perioperative haemoglobin level (Hb and Hct). As compared with group I, significant lower level of platelet counts and aggregability were observed in group II and III at the time of 24 and 48 hours after operation (P < 0.05), while postoperation blood loss and homologous blood-transfusion requirements increased at the same period (P < 0.01). CONCLUSIONS: Preoperative plateletpheresis combined with intraoperative autotransfusion can ameliorate the blood coagulation in orthopaedic patients, and it is an effective way to decrease blood loss and homologous blood-transfusions requirements.