Cardiac revascularization using both mammary arteries

Both internal mammary arteries in combination with veins were used for revascularization of the hearth in fifty Danish patients undergoing coronary artery bypass grafting (CABG) at Gentofte Hospital during the period 1994-1996. Patients with insulin-dependent diabetes mellitus, obesity, and age over 75 years were excluded. The patients were followed for at least one month after the operation. No patients died, and the complication rate was low and comparable to standard CABG using the left mammary artery and vein grafts. It is known from the literature that 10 years after CABG only 50% of vein grafts remain patent, and half of these have severe atherosclerosis. The mammary artery is far more resistant to atherosclerosis and 15 years after the procedure fewer patients have recurrent angina when both mammary arteries have been used. Bilateral mammary artery grafts can be used in half of CABG-procedures, and are especially indicated in younger patients.     

Atherosclerosis of the inferior epigastric and internal mammary arteries

Atherosclerosis of the inferior epigastric artery (IEA) and the internal mammary artery (IMA) was evaluated in 21 patients with coronary heart disease. Both arteries were used simultaneously in coronary artery bypass grafting. Histologic samples were obtained from the proximal and distal segments of IEA and from the distal segment of IMA. Morphologic findings in regard to atherosclerosis were classified semiquantitatively as normal (0), or luminal narrowing <25% (1), 25-50% (2) or >50% (3), or as overt atherosclerosis and calcification (4). Atherosclerosis was absent or minimal (1) in distal samples from both arteries. Only one IMA showed moderate (2) luminal atherosclerotic obstruction. Two samples from proximal IEA showed moderate (2) or severe (4) atherosclerotic changes which limited their use as free grafts. These finding suggest that atherosclerosis is minimal and comparable in distal IEA and IMA in their natural environments even in patients with coronary heart disease. The long-term effect of aortic pressure on free IEA graft is still unclear.     

Comparative reactivity and mechanical properties of human isolated internal mammary and radial arteries

OBJECTIVE: The aim of this study was to analyse the arterial wall mechanics and the vasoreactive properties of the radial artery in comparison with those of the internal mammary artery and to discuss their implications for coronary bypass grafts. METHODS: Measurements of pressure and diameter were obtained from cylindrical segments, whereas measurements of reactivity were obtained from ring segments from the same arteries. We used an echo-tracking technique of high resolution enabling to investigate, in vitro, the diameter and the wall thickness of arterial cylindrical segments. Furthermore, the compliance, distensibility and incremental elastic modulus of the radial and of the mammary arteries were determined for a wide range of transmural pressure (0-200 mmHg) in presence and absence of norepinephrine (NE). RESULTS: Our results show that NE caused vasoconstriction of the two arteries. Strain was found significantly higher for the radial artery than for the internal mammary artery at any given value of stress both in the presence and in the absence of NE. In presence of NE, compliance for radial artery, in the overall transmural pressure range, did not change, whereas, distensibility was significantly increased and the elastic modulus was significantly decreased. Under the same conditions, the distensibility of the mammary artery tended to decrease and its elastic modulus to increase. In parallel, the vasoreactive properties of the two arteries confirmed the previous results showing that radial artery developed a significant higher tension to vasoconstricting agents (KCl, NE and phenylephrine (PHE)) and higher relaxation to isradipine than internal mammary artery. Moreover, radial artery displayed a lesser sensitivity to sodium nitroprusside than internal mammary artery. Furthermore, sensitivity to NE was found to be 7-fold higher for radial artery than for internal mammary artery. CONCLUSION: Taken together, data on the mechanical and reactive properties of radial and internal mammary arteries show why the radial artery displayed a higher potential for spasm than the internal mammary artery and why the use of Ca2+ channel blocker can decrease the incidence of occlusion and spasm.     

Myocardial revascularization with one and two mammary arteries: clinical results and long-term follow-up

The manufacturing process for albumin in Australia is based primarily on ion-exchange chromatography. The capacity of ion-exchange matrices to remove non-enveloped viruses (canine parvovirus and poliovirus type 1) was assessed using a scaled-down chromatographic process which was shown to yield product meeting purity criteria set for the manufacturing process. Poliovirus type 1 and canine parvovirus were added at one tenth the volume of desalted and delipidated Supernatant II + III produced by traditional Cohn Fractionation from human plasma before the material was applied to DEAE and CM ion-exchangers connected in series. Samples were taken at equilibration, wash, elution and regeneration steps and the log clearance and reduction of the viruses calculated. The mean clearance and reduction factors for viral load of poliovirus type 1 were 5.3 logs and 3.2 logs, respectively and 1.8 logs and 1.8 logs for canine parvovirus.     

In coronary surgery can both internal mammary arteries be used systematically? Apropos of 560 patients

Itching is a well known side-effect of opiate therapy. To gain insight into the possible contribution of opiate receptors to itching we compared the antipruritic effect of naltrexone (Nemexin), an opiate antagonist, to an H1-receptor antagonist and to placebo. In a double blind cross-over study on 15 healthy volunteers, 25 mg naltrexone or placebo was orally given 60 min prior to a histamine stimulus. In a second, otherwise identical experiment, 10 mg cetirizine, an H1 blocker, or placebo was orally given 12 h before the experiment to the same group of volunteers. Histamine was applied iontophoretically to the forearm skin and the following parameters were assessed thereafter: weal and flare size, itch intensity and the extension of the area of alloknesis ('itchy skin') around the application site. Naltrexone had no effect on the vascular histamine reactions 'weal' and 'flare', whereas cetirizine abolished the weal reactions and greatly diminished the flare reactions. Both naltrexone and cetirizine significantly diminished histamine induced itching. In contrast to placebo and cetirizine, naltrexone abolished alloknesis completely in four of 15 volunteers and in the others alloknesis was greatly reduced after naltrexone. Since vascular reactions to histamine are of peripheral origin, whereas alloknesis depends on central nervous mechanisms, our findings suggest a pronounced centrally mediated action of naltrexone on histamine induced pruritus.     

含碳耐火材料循环利用

含碳耐火材料的循环利用,具有显著的经济效益、社会效益和环境效益,因此受到越来越多的关注。本文介绍了国内外含碳耐火材料循环利用现状,以及现有的水化和提纯处理等技术。指出目前国内在回收再利用工作中存在的产品质量与成本问题、缺乏高附加值产品、缺乏规模性和系统性研究等方面的问题。提出高效、综合利用后含碳耐火材料是今后的发展方向。     

废催化剂中金属的回收

简述了含有铂、钒、镍金属组分的废催化剂来源及金属回收工艺,介绍了萃取法在金属回收中的应用。     

Recycling of aluminum matrix composites

Separation of matrix metals in composites was tried on alumina short fiber-reinforced aluminum and 6061 alloy composites and SiC whisker-reinforced 6061 alloy composite for recycling. It is possible to separate molten matrix metals from fibers in the composites using fluxes that are used for melt treatment to remove inclusions. About 50 vol pct of the matrix metals was separated from the alumina short fiber-reinforced composites. The separation ratio of the matrix from the SiC whisker-reinforced 6061 alloy composite was low and about 20 vol pct. The separation mechanism was discussed thermodynamically using interface free energies. Since the flux/fiber interface energy is smaller than the aluminum/fiber interface energy, the replacement of aluminum with fluxes in composites takes place easily. Gases released by the decomposition of fluxes act an important role in pushing out the molten matrix metal from the composite. The role was confirmed by the great amount cavity formed in the composite after the matrix metal flowed out.     

Recycling of aluminum matric composites

Separation of matrix metals in composites was tried on alumina short fiber-reinforced aluminum and 6061 alloy composites and SiC whisker-reinforced 6061 alloy composite for recycling. It is possible to separate molten matrix metals from fibers in the composites using fluxes that are used for melt treatment to remove inclusions. About 50 vol pct of the matrix metals was separated from the alumina short fiber-reinforced composites. The separation ratio of the matrix from the SiC swisker-reinforced 6061 alloy composite was low and about 20 vol pct. The separation mechanism was discussed thermodynamically using interface free energies. Since the flux/fiber interface energy is smaller than the aluminum/fiber interface energy, the replacement of aluminum with fluxes in composites takes place easily. Gases released by the decomposition of fluxes act an important role in pushing out the molten matrix metal from the composite. The role was confirmed by the great amount cavity formed in the composite after the matrix metal flowed out.     

Hydrometallurgical Methods of Recycling Interelectrode Slime

Hydrometallurgical methods have been developed for recycling anode slime from the electrolysis of copper. The methods eliminate the need for the production and electrolytic refining of Dorr alloys and the use of costly systems for cleaning the process gases and processing large quantities of by-products. The commercial products of the new methods are metallic gold and silver (99.99%) and concentrates of nonferrous metals.     

废泡沫铝回收及循环利用

为了将废泡沫铝重熔回收,采用熔剂覆盖法进行重熔.结果表明,加入合适的熔剂,在一定温度下充分搅拌,废泡沫铝的回收率达到75%左右;回收所得的再生铝泡沫化性能和原铝类似,泡沫化制备时二者的黏度变化趋势一致,泡沫再生铝的压缩σ-ε曲线平滑,也分为线弹性阶段、屈服平台阶段和紧实阶段.     

飞灰资源化工业化的实践

飞灰资源化可以从根本上解决飞灰的出路,使生活垃圾焚烧产业发展的瓶颈得以解除,是推进生活垃圾处置产业向前发展的关键技术。上海市固体废物处置中心对飞灰资源化进行了工业规摸的实验,在控制重金属污染的前提下通过水洗的方式除去飞灰中的氯离子,处理后的飞灰用作水泥生料。实验表明,该工艺有效控制了资源化过程中的环境风险,可以环保、安全地实现飞灰的资源化。     

废铝资源再生研究现状

本文综述了废铝资源回收利用的工艺技术,主要介绍了废铝预处理技术,废铝熔炼工艺,熔体净化技术(吹气法、熔剂法、过滤法),熔体细化变质技术.与铝电解相比,废铝再生具有良好的经济效益、社会效益,该产业未来将有广阔的发展前景.     

半干法烧结烟气脱硫灰渣的资源化利用

阐述了半干法烧结烟气脱硫灰渣的成分与特点,分析了影响脱硫灰渣利用的主要因素,介绍了国内外脱硫灰渣的利用现状和资源化利用技术,提出了减少脱硫灰渣生成量的措施。     

转炉污泥资源化处理循环模式合理性的探讨

 转炉污泥资源化处理不仅有利于环保,并且回收了宝贵的铁资源,因此越来越得到重视。分析了３种循环模式,从铁资源回收率、能源消耗、处理成本、以及工艺适应性等４个方面进行深入探讨,指出了转炉污泥经碱性球团厂制成球团,作为化渣剂直接返回转炉是资源化处理较合理的循环模式。