INFLUENCES OF MICRO-ALLOY AND HEAT-TREATMENT PROCEDURE ON THE HARDENING OF DJ108TI ALLOY

The influences of micro alloy and heat treatment procedure on the hardening of DJ108Ti alloy, which is based on the electrolytic Al Si(2 05%) Ti(0 25%) Fe(0 30%) multi component alloy, have been investigated. The results indicate that the micro alloy based on the multi component alloy makes α Al dendrites in DJ108Ti alloy refined; that the improved heat treatment procedure makes the eutectic Si phases granulated , the Fe phase refined, and the strengthening phases of Mg2Si and Al2Cu fully precipitated. The micro alloy and the heat treatment procedure harden DJ108Ti alloy and benefit the abrasion resistance of the alloy

Individual flexible endoscopic procedure for treatment of obstruction of fourth ventricle outlet

Objective To summarize the indication,method and effect of individual flexible endoscopic procedure for treatment of obstruction of fourth ventricle outlet. Methods The clinical data of 32 cases of obstruction of fourth ventricle outlet treated by individual flexible endoscopic

Aortic root replacement

Objective To report our operative experience with aortic root replacement in 231 patients with aortic root aneurysm and discuss the current indications, methods, and surgical techniques、Methods Between January 1994 and August 1999, a group of 231 consecutive patients underwent aortic root replacement at our hospital, with 13 being treated on an emergency basis、 There were 189 men and 42 women, ranging in age from 14 to 69 years、 The diameter of the aneurysm varied from 4、5 to 11?cm、 Among this group, 145 had isolated aortic root aneurysms, 65 suffered from DeBakey type Ⅰ aortic dissection, and the remaining 21 were diagnosed as having DeBakey type Ⅱ aortic dissection、 Aortic valve regurgitation occurred in all cases、 Aortic root replacement was performed with composite valved graft in 229 patients, and in 2 patients the aortic valve was preserved、Results The hospital mortality rate was 3、03% (7 patients)、 Early complications included re-exploration for bleeding in 6 patients, pericardial effusion in 9, as well as cerebral infarction, pleural effusion, and pneumothorax in 2 patients each、 One hundred and seventy-five patients (78、12%) were followed up, with a mean follow-up time of 15、7±13、1 months (range, 2 weeks to 65 months)、 One patient died from lower-limb embolism and renal dysfunction 3 months postoperatively、 Three patients died from postoperative anticoagulation accidents、 The preoperative and postoperative mean left ventricular end-diastolic diameters were significantly different (68、1±9、4?mm, range 54 to 112?mm; vs 54、8±8、2?mm, range 38 to 88?mm; P<0、001)、Conclusions Once a diagnosis of acute aortic root dissecting aneurysm is made, the patient should undergo surgery as soon as possible if the general conditions permit、 Aortic aneurysm without dissection or with chronic dissection should be operated if the diameter of the aneurysm is greater than 5?cm

Safety and efficacy of laser and cold knife urethrotomy for urethral stricture

Background Endoscopic treatment for urethral stricture, including cold knife and laser, poses a major challenge to clinical practice. Both the benefits and drawbacks of these two treatments remain controversial. This article aimed to compare the efficacy and safety of laser and cold knife urethrotomy for urethral stricture. Methods We searched PubMed （1966-2009）, Embase （1980-2009）, Cochrane Central Register of Controlled Trials （CCRCT, 2009 No.l） and Chinese Biomedical Literature Database （CBM） for laser and cold knife urethrotomy as treatment for male urethral stenosis, looking in the English literatures. Two reviewers independently screened the literatures and extracted information. Chi-square test was used for statistical analysis with SPSS15.0. Results A total of 44 articles, including of 3230 cases was retrieved. Success rate of patients treated with laser was 74.9% compared with 68.5% for cold knife, with very similar clinical results despite a statistically significant difference （P=-0.004）. The trend in success rate at a different follow-up time was similar between the two groups. No significant difference in success rate was found between the groups of repeat operation for recurrence cases, first P=0.090 and second P=0.459. The shorter the stricture length was （〈1 cm）, the higher the success rate was （P 〈0.0001）. No significant difference in success rate between the laser and cold knife groups was found in neither bulbar nor membranous urethra, bulbar P=0.660 and membranous P=0.477. The rates of urinary incontinence, urinary extravasation, and urinary tract infection showed no significant difference （P=-0.259, P=0.938, P=-0.653, respectively）. Conclusions Success rates for laser and cold knife were very similar despite being statistically different, with the groups having a similar trend in success rates at different follow-up time. Stricture location and history of endoscopic intervention did impact treatment outcome but was not significantly different. The two groups showed no significant difference in major complications.