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CdSe nanocrystals with a zinc blende structure allowed apparent Mg doping (∼9.8 at.%). Inverse micelles were formed at a low temperature as templates for the zinc blende CdSe nanocrystals, and paraffin oil and oleic acid were used as a solvent and a surfactant, respectively. The Mg doping was shown by energy dispersive x-ray spectroscopy (EDS) and inductively coupled plasma (ICP) atomic emission analyses. Although the particle size of the CdSe and Mg-doped CdSe nanocrystals were ∼6 and ∼8 nm, respectively, the Mg-doped ones show the obvious blueshift in the UV–visible absorption spectra due to the increase in the bulk energy bandgap, which is decisive evidence for the real Mg doping in the CdSe lattices. The Mg-doped CdSe nanocrystals also showed the blueshift in the photoluminescence (PL) spectra, and their PL intensity was comparable to or even higher than that of the undoped CdSe. This impurity doping using the zinc blende structure is suggested as a simple and effective way to tune the energy bandgap of CdSe nanocrystals and, in turn, to control their light emission colour.

BackgroundThis study was performed to compare the effectiveness of prophylactic dexamethasone and postintubation dexamethasone in reducing the incidence and severity of postoperative sore throat (POST).MethodsThis was a prospective, randomized, double-blind clinical trial. The study population consisted of 70 patients between 20 and 60 years old who were classified as American Society of Anesthesiologists I-II and were scheduled for elective laparoscopic cholecystectomy. The patients were divided randomly into two groups. Patients in the prophylactic and postintubation groups received intravenous injection of 10 mg of dexamethasone 30 min before or after tracheal intubation, respectively. The patients were interviewed 1, 6, and 24 h after the operation. The incidence and severity of POST were recorded.ResultsThe severity scores of POST at 1 and 6 h after the operation were significantly lower in the prophylactic group than in the postintubation group. There were no significant differences in the incidence of POST during the 24 h after the operation between the two groups (22/32 in the prophylactic group vs. 27/34 in the postintubation group, P = 0.403).ConclusionsIntravenous injection of 10 mg of dexamethasone was more effective in reducing the severity of POST when administered before tracheal intubation compared with after tracheal intubation.

BackgroundKetamine, an N-methyl-D-aspartate receptor antagonist, might play a role in postoperative analgesia, but its effect on postoperative pain after caesarean section varies with study design. We investigated whether the preemptive administration of low-dose intravenous ketamine decreases postoperative opioid requirement and postoperative pain in parturients receiving intravenous fentanyl with patient-controlled analgesia (PCA) following caesarean section.MethodsSpinal anesthesia was performed in 40 parturients scheduled for elective caesarean section. Patients in the ketamine group received a 0.5 mg/kg ketamine bolus intravenously followed by 0.25 mg/kg/h continuous infusion during the operation. The control group received the same volume of normal saline. Immediately after surgery, the patients were connected to a PCA device set to deliver 25-µg fentanyl as an intravenous bolus with a 15-min lockout interval and no continuous dose. Postoperative pain was assessed using the cumulative dose of fentanyl and visual analog scale (VAS) scores at 2, 6, 24, and 48 h postoperatively.ResultsSignificantly less fentanyl was used in the ketamine group 2 h after surgery (P = 0.033), but the difference was not significant at 6, 12, and 24 h postoperatively. No significant differences were observed between the VAS scores of the two groups at 2, 6, 12, and 24 h postoperatively.ConclusionsIntraoperative low-dose ketamine did not have a preemptive analgesic effect and was not effective as an adjuvant to decrease opioid requirement or postoperative pain score in parturients receiving intravenous PCA with fentanyl after caesarean section.

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Poly(ethylene oxide) (PEO)-titania (TiO 2 ) organic-inorganic hybrid particles were synthesized using sol-gel chemistry and crystallized at 600, 800, and 900 °C. Anatase/rutile core/shell-structured titania particles were obtained through partial phase transformation (∼70%) of anatase to rutile at 800 °C. The mechanism of core/shell structure formation was proposed as the shrinkage during anataseto-rutile phase transformation, the difference in the thermal expansion coefficient (TEC) of two crystals, and further decomposition of remaining organic components trapped in the core. The core/shell particles showed enhanced photodecomposition rates compared to spherical shape particles and other commercially available particles most probably due to the increased surface area by the nanoporous and nanocrystalline structure of the anatase core.

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