Low temperature synthesis of NiO/CoO nanostructures to enhance their low temperature oxygen reduction catalysis.

"Thermal expansion and cold contraction" are common occurrences in nature. Resulting from "thermal expansion and cold contraction" reaction, strain effect is created, which affects the oxygen reduction reaction (ORR) activities of fuel cell catalysts. Nevertheless, the "thermal expansion and cold contraction" effects of catalysts have rarely been investigated. Herein, the influence of "thermal expansion and cold contraction" strains upon ORR activities of NiO/CoO catalysts is investigated. Experimental and first-principles calculations reveal that, when NiO/CoO are synthesized and used as catalysts under low temperature ice/water environment, there is virtually no strain effect created, and abundant active sites contribute to the good low temperature ORR activities of NiO/CoO catalysts (onset potential: 0.736 V, halfwave potential: 0.659 V). When high temperature synthesized NiO/CoO catalysts are used at low temperature, however, small amounts of active sites are created. Moreover, the adsorption activity of NiO(222) and CoO(311) stepped active sites are weakened by compressive strain of lattice contraction, which reduces their ORR activities. The "low temperature synthesis and low temperature catalysis" route proposed by this paper paves a new road for the synthesis and design of low-temperature catalysts.

Perioperative management for primary tracheal malignant tumors resected under cardiopulmonary bypass / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To retrospectively review the perioperative management for primary tracheal malignant tumors resected under cardiopulmonary bypass.</p><p><b>METHODS</b>The data of 6 patients with primary tracheal malignant tumors who underwent surgery under cardiopulmonary bypass from December 1999 to August 2003 were reviewed. Cardiopulmonary bypass was established through right femoral vessels in 2 patients for emergency operation, through right atrium and ascending aorta in 4 patients. Sleeve tracheal resections in 3 patients, carinal resections and carina reconstructions in 2, and local enucleation in 1 were performed. Respiratory airway was kept patent by coughing and expectorating sputum.</p><p><b>RESULTS</b>All patients' dyspnea were relieved remarkably. The postoperative mechanic ventilation assistance lasted from 10 hours to 7 days. There was no perioperative mortality.</p><p><b>CONCLUSION</b>Resection of primary tracheal malignant tumors with severe tracheal obstruction under cardiopulmonary bypass is practicable. Keeping respiratory airway patent perioperatively is very important and helpful to postoperative recovery.</p>

Non-invasive imaging of coronary artery with 16-slice spiral computed tomography / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis.</p><p><b>METHODS</b>Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensation 16, Siemens, Germany) in 230 patients with suspected coronary heart disease (CHD). Parameters of the plain scan were: 120 kV, 133 mA, slice collimation 16 mm x 1.5 mm, rotation time 0.42 seconds, increment 1.5 mm, and slice width 3 mm. Parameters of the enhanced scan were: 120 kV, 500 mA, slice collimation 16 mm x 0.75 mm, rotation time 0.42 seconds, increment 0.5 mm, and slice width 1 mm. Enhanced CT scan was performed with a rapid intravenous injection of 100 mL iothalamate meglumine (Ultravist) (370 mgI/mL) or Omnipaque (350 mgI/mL) and 30 mL 0.9% NaCl chaser bolus at a flow rate of 3.5 mL/s. Calcium scoring with plain scan images and two and three dimensional reconstruction with enhanced scan images were made in all cases, among which 30 cases underwent conventional coronary angiography. Demonstration of coronary arteries and their stenosis were evaluated and the factors that might influence the image quality were analyzed.</p><p><b>RESULTS</b>Coronary calcium scores were calculated and coronary artery was demonstrated in our study. In the evaluation of image quality with volume rendering technique (VRT) images, 78.3% of the images were of the first class, 12.2% the second class, and 9.6% the third class. Multi-planar reconstruction (MPR) and maximal intensity projection (MIP) were better than VRT in the demonstration of small branches. The image quality was related to the heart rate, with or without arrhythmia, and breath-hold ability of patients. Comparative study of the stenosis of coronary arteries in 30 cases showed that the sensitivity and specificity of 16-slice coronary CT angiography (CTA) to diagnose significant stenosis were 95.8% and 94.8% respectively.</p><p><b>CONCLUSION</b>As a non-invasive and quick method, 16-slice coronary CTA is sensitive and specific to diagnose the stenosis of coronary arteries and can be used as a screening method in the diagnosis of CHD.</p>

Surgical management of metastatic disease in the conjunctive area between neck and thorax / 中国医学科学院学报

<p><b>OBJECTIVE</b>To study the surgical management of metastatic disease in the conjunctive area between the neck and thorax and its efficacy.</p><p><b>METHODS</b>Fourteen cases with metastatic node disease in the area between neck and thorax were collected and analysed. Eleven tumors were from the thyroid cancer, and the other three were from the hypopharyngeal cancer, esophagual cancer and malignant pheochromocytoma, respectively. The clavicle was displaced or resected, and the upper half of the manubrium might also be resected when necessary. The recurrent laryngeal nerve and phrenic nerve were exposed and protected. The metastatic disease was completely removed with the internal jugular and/or the brachiocephalic vein resected or spared, depending on the disease condition.</p><p><b>RESULTS</b>In 10 cases with metastases from the thyroid, no local recurrence was found within the follow-up period from 2 to 5 years. In contrast, no patient with metastatic disease from hypopharyngeal or esophageal cancer survived more than 11 months. No serious complications were found in this group.</p><p><b>CONCLUSIONS</b>The surgical treatment of node metastases in the conjunctive area between neck and thorax from the well-developed thyroid cancer has promising effect and is comparatively safe.</p>