RESUMEN
This study suggests combustion synthesized Ce(1-x)Zr(x)O(2) (CZO; x = 0.1-0.5) as a new catalyst for the cathode in non-aqueous electrolyte based Li/O(2) cells. The spherical catalysts have a fluorite structure with a mean diameter of 5-17 nm. Zr doping into the ceria lattice leads to the reduction of Ce(4+) to Ce(3+), which further improves the catalyst performance. Electrochemical studies of CZO as a cathode catalyst in the Li/O(2) cell show that CZO follows a two-electron pathway for oxygen reduction. A maximum discharge capacity of 1620 mAh g(-1) is obtained for the Ce(0.8)Zr(0.2)O(2) catalyst due to its high surface area and porosity. A composite of CZO and MnO(2) shows even better performance as a cathode catalyst for the Li/O(2) cell.
RESUMEN
Olivine structured LiFePO4 samples were synthesized by solvothermal process using various polyol media of ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), and tetraethylene glycol (TTEG) without any heating as a post procedure. The X-ray diffraction patterns of the samples prepared in EG and DEG showed the crystalline peaks with well-fitted to the positions on the basis of an olivine type structure without any impurities. In order to determine the unit cell parameters, synchrotron powder XRD patterns were fitted with whole-pattern profile matching method using FULLPROF program. The obtained samples exhibited well dispersed nanoplate morphologies excepting for the sample prepared in EG. The samples prepared in EG, DEG, TEG, and TTEG showed the reversible capacity of 118, 167, 90, and 105 mAh/g at current density of 0.1 mA/cm2, respectively. Among them, the samples reacted in DEG and TTEG showed good performances at high rate of 16C with high capacities retention.
RESUMEN
BACKGROUND: 5-HT3 receptor antagonist, dexamethasone and droperidol were used for the prevention of postoperative nausea and vomiting (PONV). Recently, neurokinin-1 (NK1) antagonist has been used for PONV. We evaluated the effect of oral aprepitant premedication in addition to ondansetron. METHODS: A total 90 patients scheduled for elective rhinolaryngological surgery were allocated to three groups (Control, Ap80, Ap125), each of 30 at random. Ondansetron 4 mg was injected intravenously to all patients just before the end of surgery. On the morning of surgery, 80 mg and 125 mg aprepitant were additionally administered into the Ap80 group and Ap125 group, respectively. The rhodes index of nausea, vomiting and retching (RINVR) was checked at 6 hr and 24 hr after surgery. RESULTS: Twelve patients who used steroids unexpectedly were excluded. Finally 78 patients (control : Ap80 : Ap125 = 24 : 28 : 26) were enrolled. Overall PONV occurrence rate of Ap125 group (1/26, 3.9%) was lower (P = 0.015) than the control group (7/24, 29.2%) at 6 hr after surgery. The nausea distress score of Ap125 group (0.04 ± 0.20) was lower (P = 0.032) than the control group (0.67 ± 1.24) at 6 hr after surgery. No evident side effect of aprepitant was observed. CONCLUSIONS: Oral aprepitant 125 mg can be used as combination therapy for the prevention of PONV.
RESUMEN
Central venous catheterization (CVC) can be difficult, especially with pediatric patients in critical care. Accessing the subclavian vein (SCV) can cause serious complications, including pneumothorax, arterial puncture, and hemothorax. Recently, the ultrasonographic (USG) technique has gained popularity, but its efficiency is not yet confirmed. Subclavian venous catheterization (SCVC) through the supraclavicular approach (SCA) with USG or accessing the brachiocephalic vein through the infraclavicular approach (ICA) has been reported in the past. A useful technique is reported that involves the use of a 40 mm probe rather than the usual 25 mm probe in order to confirm the location of the needle while successfully performing subclavian venous catheterization in pediatric patients weighing 1.1 kg to 15.0 kg.