Evaluation of fracture healing in man by serial 99mTcSn-pyrophosphate scintimetry

Serial 99mTc-pyrophosphate (99mTcPP) uptake measurements were performed, during the healing period, in 12 patients with fracture of the distal end of the radius without displacement. A peak value in uptake ratio was seen within 4 weeks in all patients. For clinical reasons the patients were divided into a normal healing and a slow healing group. 99mTcPP uptake at 6 weeks after the fracture was significantly higher in the slow healing group. Quantitation of the healing process in forearm fractures is possible using 99mTcPP and a gamma camera, and concentrating on small selected areas of interest.     

The Troms?o heart study. Methods and main results of the cross-sectional study

The mortality from coronary heart disease (CHD) in Norway increased rapidly during 1951-70, the highest mortality rates as well as the most rapid increases being found in Northern Norway. Several surveys of CHD were then planned, one of them is reported here. All men, 20-49 years of age, living in the municipality of Troms?o, Troms county, were called up for examination. In total, 6595 men, 74.4% of those invited, were examined. Cholesterol, triglyceride and Hb values, BP, body weight and height, the percentage of smokers, and cigarette consumption have been tabulated according to area, age, work schedule, health condition, physical activity and ethnic background. The results suggest that the relatively high mortality from CHD in Northern Norway is associated with high serum cholesterol concentrations as well as a relatively high prevalence of smoking. During the screening there were indications of changes in dietary habits in the municipality, presumably as a result of accompanying publicity.     

Visible light photocatalytic properties of novel molybdenum treated carbon nanotube/titania composites

Two types of molybdenum–carbon nanotubes and molybdenum treated carbon nanotubes/titania composites were prepared using a sol–gel method. These composites were characterized comprehensively by the Brauer–Emett–Teller (BET) surface area, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. It was found that the photocatalytic degradation of a methylene blue solution could be attributed to the combined effects caused by the photo-degradation of titania, the electron assistance of carbon nanotube network, and the enhancement of molybdenum. The proposed redox mechanism of the photodegradation of methylene blue on Mo-CNT/TiO₂ composites is suggested.     

Effect of Mg composition on sintering behaviors and mechanical properties of Al–Cu–Mg alloy

Al–3Cu–Mg alloy was fabricated by the powder metallurgy (P/M) processes. Air-atomized powders of each alloying element were blended with various Mg contents (0.5%, 1.5%, and 2.5%, mass fraction). The compaction pressure was selected to achieve the elastic deformation, local plastic deformation, and plastic deformation of powders, respectively, and the sintering temperatures for each composition were determined, where the liquid phase sintering of Cu is dominant. The microstructural analysis of sintered materials was performed using optical microscope (OM) and scanning electron microscope (SEM) to investigate the sintering behaviors and fracture characteristics. The transverse rupture strength (TRS) of sintered materials decreased with greater Mg content (Al–3Cu–2.5Mg). However, Al–3Cu–0.5Mg alloy exhibited moderate TRS but higher specific strength than Al–3Cu without Mg addition.     

Effects of various sintering methods on microstructure and mechanical properties of CP-Ti powder consolidations

Effects of various sintering methods such as spark plasma sintering (SPS), hot pressing (HP) and electric resistance sintering (ERS) on the microstructure and mechanical properties of commercial pure titanium (CP-Ti) powder consolidations with particle size of <147 μm, <74 μm and <43 μm were studied. The smaller particle powders are densified to proceed at a higher rate. Dense titanium with relative density up to 99% is found to take place at 850 °C under 30 MPa of SPS and HP condition. However, in case of ERS, CP-Ti powders were densified almost at 950 °C under 30 MPa. The microstructure of sintered titanium is composed of equiaxed grains at 850–950 °C. The yield strength of sintered body composed of <43 μm powder is 858 MPa by using SPS at 850 °C under 30 MPa. When there is a higher content of small particle, the higher yield strength value is obtained both by using SPS and HP. However, when ERS is introduced, the highest yield strength is 441 MPa at 950 °C under 30 MPa, which shows much lower values than those by SPS and HP methods. ERS method takes much less sintering time compared with SPS and HP. Nevertheless, higher sintering temperature results in lower strength and elongation because of brittle fracture.     

植物修复技术在污染土壤修复中的应用

土壤是人类赖以生活和生产的最重要自然资源,但人类活动或自然作用能导致土壤污染。如何将被污染的土壤作为宝贵的自然资源进行修复是一个世界性的难题。近年来利用绿色植物修复污染土壤被视为一项新兴的绿色技术而迅速发展。本文就污染土壤的植物修复技术原理、研究现状、实用化促进等方面作一些介绍和讨论。植物修复技术是利用植物吸收、固定、挥发、降解的机能去除或分解转化污染物质,使土壤系统的功能得到恢复或改善,属于一种低成本、非破坏型的原位污染土壤修复与土壤资源保护方式。根据其作用过程和原理,可以分为植物萃取、根际过滤、植物固定、植物挥发、植物降解等类型。植物修复技术的研究在80年代之后逐渐展开,目前在重金属超富集型植物的发现和富集机理、各种无机污染物和有机污染物的植物修复与机理、修复效率促进、污染场地的试验性修复等方面得到广泛研究,但还没有达到广泛普及应用的程度。本文指出,对于范围广面积大的土壤污染,建立有效的收益型植物修复模式, 将污染土壤作为可再生资源边利用边修复是非常必要的。