Synthesis of poly (N-isopropylacrylamide)-co-(acrylic acid) microgel-entrapped CdS quantum dots and their photocatalytic degradation of an organic dye.

CdS quantum dots (CdSQDs) were generated inside the network structure of poly (N-isopropylacrylamide)-co-(acrylic acid) (pNIPAm-co-AAc) microgels and their ability to photocatalytically degrade organic dyes was evaluated using rhodamine B (RhB). The microgel-stabilized CdSQDs were generated by first enriching the microgels with Cd2+ followed by their reaction with Na2S. The resultant microgels were characterized, and the CdSQDs were found to be distributed throughout the microgels. We went on to show that the hybrid microgels exhibited photocatalytic properties by exposing them to a solution of RhB followed by exposure to UV irradiation. We found that the hybrid microgels were able to degrade the RhB, while native microgels without CdSQDs present were not capable of the same behavior. Due to the thermo- and pH-responsivity of pNIPAm-co-AAc-based microgels their ability to degrade RhB was also evaluated as a function of environmental temperature and solution pH. We showed that the removal efficiency was highest when the microgels were in their swollen state, which we attribute to more effective mass transfer of the RhB inside the microgels when their porous structure is expanded. Finally, we show that the hybrid microgels can be reused multiple times, although their photocatalytic degradation ability decreases the more they are used, which may be a result of the aggregation and decomposition of the CdSQDs. We conclude that this approach is an effective means of removing RhB from water, which may be modified to photodegrade a variety of other organic compounds.

[Automatic decompression with micro-catheter for open and tension pneumothorax].

OBJECTIVE: To evaluate the feasibility of treating pneumothorax with automatic intermittent decompression with micro-catheter instead of traditional thorax water sealed drainage (TWSD). METHODS: The automatic decompression instrument (ADI), which decompressed intermittently with programmed control, was designed and assembled by the authors (Patent No. ZL 01242081.6). A prospective study of the efficacy of this device was conducted in 87 pneumatothorax cases, and the results were compared with those of TWSD. RESULTS: The average time of closure in ADI group was 4.12+/-0.98 days, which was significantly shorter than that with TWSD (6.83+/-2.06 days, P<0.01). The incidence of complications was also significantly lower in ADI patients (P<0.01), and none of them developed severe complications. Clinical cure was achieved in all the patients in ADI group except for two patients who gave up treatment voluntarily and one transferred for open surgery. CONCLUSIONS: Application of ADI allows faster healing and safer and easier operation, and causes fewer complications and less pain with shortened hospital stay as compared with conventional therapy for open and tension pneumothorax.