喷射沉积Al5.5Cu/TiB_2自生复合材料的界面结构

运用ＴＥＭ 观察了铸态、喷射沉积态Ａｌ５ ．５Ｃｕ／ＴｉＢ２ 复合材料中ＴｉＢ２ 与基体的界面结构,发现在铸态时ＴｉＢ２ 与α（Ａｌ） 之间存在的位向关系为［０３３２］ ＴｉＢ２ ∥［１１０］ α（Ａｌ） ,（０１１１）ＴｉＢ２ ∥（００２） α（Ａｌ） , 而在沉积态时其位向关系为［０００１］ ＴｉＢ２ ∥［１１１］ α（Ａｌ） ,（１１２０）ＴｉＢ２ ∥（２２０）α（Ａｌ） 。力学性能测试结果表明： 喷射沉积后的Ａｌ５ ．５Ｃｕ／ＴｉＢ２ 自生复合材料的抗拉强度比铸态提高约５０ ＭＰａ , 延伸率则提高５００ ％ 左右,耐磨性能也有较大提高     

Postnatal survival and growth of mouse irradiated in utero with low dose

In order to investigate radiation risks associated with low dose and low dose-rates, pregnant Swiss albino mice were exposed to gamma rays, 0.80 Gy from a cobalt-60 source at two different dose-rates (0.0795 and 0.0012 Gy/min) on 18 day post conception. In females exposed to lower dose-rate (0.0012 Gy/min), litter size was found to be decreased, while those exposed to higher dose-rate (0.0795 Gy/min), it remained unaltered. In both groups, appearance of fur and development of complete fur were delayed, whereas gait was delayed only in higher dose-rate group. Male offspring exhibited a biphasic mode of weight loss, while female offspring after an initial weight loss at 1 week, displayed a continuous recovery, but could not attain the normal weight till 12 weeks of age. It appears that higher dose-rate is more effective in delaying the appearance of physiological markers and weight loss, while in terms of litter size lower dose-rate (0.0012 Gy/min) is more effective.     

Nitric oxide-producing neurons remain intact after small bowel transplantation

This study documents the fate of nitric oxide neurons following small bowel transplantation. Heterotopic, syngeneic small bowel transplants were performed in five male Lewis rats. The grafts were harvested 7, 36, 55, 60, and 65 days postoperatively, together with the native bowel for comparison. NADPH diaphorase staining of cryostat sections was used to identify the nitric oxide-producing neurons. NADPH diaphorase activity was concentrated in the myenteric plexus, deep muscular, and submucous plexus. No differences were detected between the transplanted and native bowel at any time after transplantation. This suggests that nitric-oxide-producing neurons are well preserved after transplantation and that posttransplant dysmotility is probably not related to interrupted nitric oxide innervation.     

Lichtenstein herniotomy

All standard methods of hernia repair involve suturing together tissues which are not normally in apposition. This violates the basic surgical principle that tissue must never be approximated under tension and accounts for an unacceptable number of failures. Total reinforcement of the inguinal floor with a sheet of suitable biomaterial and employment of a "tension-free" technique is a more effective approach. Since June 1984, 3250 primary inguinal hernias have been repaired at the Lichtenstein Hernia Institute by the open tension-free technique using Marlex mesh. All operations were performed under local anesthesia. Patients were discharged from the hospital within two or four hours after the operation. The patients were followed from one to 8 years by physician examination. The follow-up rate was 87%. There were four recurrences. The causes of recurrence and how to avoid them are discussed.     

Effect of polymerization temperature and time on the residual monomer content of denture base polymers

The aim of this study was to investigate the effect of polymerization time and polymerization temperature on the residual methyl methacrylate (MMA) content of two heat-cured and two autopolymerized denture base polymers. Gas chromatography was used to determine the residual MMA content of three test specimens of each type of polymer. Increasing the polymerization temperature for the autopolymerized denture base resins from 30 degrees C to 60 degrees C decreased the residual MMA content of the polymer from an average of 4.6 wt% to 3.3 wt%. With the heat-cured denture base resins, a curing cycle at a polymerization temperature of 70 degrees C followed by a period at 100 degrees C significantly reduced the residual monomer content of the polymer when compared with a resin cured at 70 degrees C only. Polymerizing the heat-cured denture base resin at 100 degrees C only for various lengths of time significantly affected the residual MMA content of the polymer. The lowest residual MMA content (0.07 wt%) was obtained by polymerizing the heat-cured denture base resin at 100 degrees C for 12 h. The results of this study suggest that the polymerization temperature and polymerization time considerably affect the residual MMA content of denture base polymers.     

Therapy of a xenografted human colonic carcinoma using cisplatin or doxorubicin encapsulated in long-circulating pegylated stealth liposomes

The present paper describes AMmtDB, a database collecting the multi-aligned sequences of vertebrate mitochondrial genes coding for proteins and tRNAs, as well as the multiple alignment of the mammalian mtDNA main regulatory region (D-loop) sequences. The genes coding for proteins are multi-aligned based on the translated sequences and both the nucleotide and amino acid multi-alignments are provided. As far as the genes coding for tRNAs are concerned, the multi-alignments based on the primary and the secondary structures are both provided; for the mammalian D-loop multi-alignments we report the conserved regions of the entire D-loop (CSB1, CSB2, CSB3, the central region, ETAS1 and ETAS2) as defined by Sbisà et al. [ Gene (1997), 205, 125-140). A flatfile format for AMmtDB has been designed allowing its implementation in SRS (http://bio-www.ba.cnr.it:8000/BioWWW/#AMMTDB ). Data selected through SRS can be managed using GeneDoc or other programs for the management of multi-aligned data depending on the user's operative system. The multiple alignments have been produced with CLUSTALV and PILEUP programs and then carefully optimized manually.     

ITA study of non-destructive methods of inspecting and testing tunnel linings

The International Tunneling Association's Working Group on Maintenance and Repair of Underground Structures is preparing a report dealing with non-destructive methods of inspecting and testing tunnel linings. This request for information details the scope of the group's work and the types of information the group is seeking at this time.