On the effect of solvent/nonsolvent combination in the column fractionation of polymers

The effect of some solvent/nonsolvent pairs on the efficiency of the column fractionation of polystyrene was investigated. Extensive cloud point titration experiments were shown to be needed for the correct assessment of thermodynamic qualities of a solvent/nonsolvent pair used in the column fractionation of polymers. Besides the thermodynamic suitability of solvent pairs their kinetic behavior was shown to differ. Possible reasons for the observed differences were discussed.     

Occupational class and ischemic heart disease mortality in the United States and 11 European countries.

OBJECTIVES: Twelve countries were compared with respect to occupational class differences in ischemic heart disease mortality in order to identify factors that are associated with smaller or larger mortality differences. METHODS: Data on mortality by occupational class among men aged 30 to 64 years were obtained from national longitudinal or cross-sectional studies for the 1980s. A common occupational class scheme was applied to most countries. Potential effects of the main data problems were evaluated quantitatively. RESULTS: A north-south contrast existed within Europe. In England and Wales, Ireland, and Nordic countries, manual classes had higher mortality rates than nonmanual classes. In France, Switzerland, and Mediterranean countries, manual classes had mortality rates as low as, or lower than, those among nonmanual classes. Compared with Northern Europe, mortality differences in the United States were smaller (among men aged 30-44 years) or about as large (among men aged 45-64 years). CONCLUSIONS: The results underline the highly variable nature of socioeconomic inequalities in ischemic heart disease mortality. These inequalities appear to be highly sensitive to social gradients in behavioral risk factors. These risk factor gradients are determined by cultural as well as socioeconomic developments.     

Socioeconomic inequalities in mortality among women and among men: an international study

OBJECTIVES: This study compared differences in total and cause-specific mortality by educational level among women with those among men in 7 countries: the United States, Finland, Norway, Italy, the Czech Republic, Hungary, and Estonia. METHODS: National data were obtained for the period ca. 1980 to ca. 1990. Age-adjusted rate ratios comparing a broad lower-educational group with a broad upper-educational group were calculated with Poisson regression analysis. RESULTS: Total mortality rate ratios among women ranged from 1.09 in the Czech Republic to 1.31 in the United States and Estonia. Higher mortality rates among lower-educated women were found for most causes of death, but not for neoplasms. Relative inequalities in total mortality tended to be smaller among women than among men. In the United States and Western Europe, but not in Central and Eastern Europe, this sex difference was largely due to differences between women and men in cause-of-death pattern. For specific causes of death, inequalities are usually larger among men. CONCLUSIONS: Further study of the interaction between socioeconomic factors, sex, and mortality may provide important clues to the explanation of inequalities in health.     

Concomitant radiotherapy with mitomycin C and bleomycin compared with radiotherapy alone in inoperable head and neck cancer: final report

Purpose: To compare the efficacy of concomitant irradiation with mitomycin C and bleomycin in patients with inoperable head and neck carcinoma with radiotherapy alone.

Methods and materials: Between March 1991 and December 1993, 64 patients with inoperable head and neck carcinoma (41 with oropharyngeal site) were randomized to radiotherapy alone (group A) or radiotherapy combined with simultaneous application of mitomycin C and bleomycin (group B). In both groups patients were irradiated five times weekly with 2 Gy to a total dose of 66–70 Gy. The planned concomitant treatment in group B was: bleomycin 5 units twice a week IM, total dose 70 units, mitomycin C 15 mg/m² IV after delivery of 10 Gy, and 10 mg/m² IV on the last day of radiotherapy. To enhance the effect of these two drugs, patients received also nicotinamide, chlorpromazine, and dicoumarol.

Because significantly better results were achieved in arm B for patients with inoperable oropharyngeal carcinoma, the study was closed and such patients were after December 1993 routinely treated with the combined therapy (as in arm B). Until October 1996, we treated and followed up 48 such consecutive patients.

Results: Median follow-up of our study patients is 42 months. Complete remission (CR) rate in group A was 31% and in group B 59% (p = 0.04); disease-free survival (DFS) in group A was 8% and in group B 37% (P = 0.01); and overall survival (OS) was 7% in group A and 26% in group B (p = 0.08). CR rate for patients with oropharyngeal carcinoma was 29% in group A (N = 21) and 75% in group B (N = 20) (p = 0.007); DFS in group A was 10% and in group B 48% (p = 0.001); and the OS was 10% in group A and 38% in group B (p = 0.019). In patients with inoperable oropharyngeal carcinoma treated after December 1993, complete remission was achieved in 32/48 (67%, 95% CI: 52%–80%). DFS at the median follow-up of 14 months was 60% (95% CI 43–77%) and OS 58% (95% CI 42–74%).

Conclusion: From the results of our study it seems that the concomitant treatment significantly improves CR rate, DFS, and OS in patients with inoperable oropharyngeal carcinoma in comparison with radiotherapy alone.     

Desflurane induces only minor Ca2+ release from the sarcoplasmic reticulum of mammalian skeletal muscle

BACKGROUND: Desflurane is a weaker trigger of malignant hyperthermia than is halothane. There are very few data of the pathophysiologic background of this observation. Therefore, the authors' aim was to investigate the direct effect of desflurane on calcium release in skinned skeletal muscle fibers. METHODS: For the measurements, single saponin-skinned muscle fiber preparations of BALB/c mice were used. For Ca2+ release experiments, liquid desflurane at 0.6 and 3.5 mm was applied to weakly calcium-buffered solutions with no added Ca2+. Desflurane was diluted in strongly Ca2+-buffered solutions, with [Ca2+] between 3.0 and 24.9 micrometer for [Ca2+]-force relations. Force transients were transformed into Ca2+ transients based on the individual [Ca2+]-force relations. As controls, 30 mm caffeine and equimolar sevoflurane were investigated in the same muscle fibers. RESULTS: At 3.5 mm, desflurane induced peak force transients of 8 +/- 4% (mean +/- SD) of maximal Ca2+-activated force (Tmax). These peak values were significantly smaller than those in the presence of 3.5 mm sevoflurane (24 +/- 10% of Tmax, P < 0.05), and 4 or 5 times smaller than previously reported Ca2+-release-induced force transients by equimolar halothane. Calculated peak Ca2+ transients derived from force transients and induced by 3.5 and 0.6 mm desflurane were significantly smaller than those induced by 30 mm caffeine. The [Ca2+]-force relation was shifted by desflurane, resulting in a Ca2+-sensitizing effect. The maximal Ca2+-activated force was significantly increased by 0.6 mm desflurane in comparison with the control, with no added substance (P 相似文献   

Carbonation Behavior of Engineered Cementitious Composites under Coupled Sustained Flexural Load and Accelerated Carbonation

Engineered cementitious composites (ECCs) belong to a broad class of fibre-reinforced concrete. They incorporate synthetic polyvinyl alcohol (PVA) fibres, cement, fly ash and fine aggregates, and are designed to have a tensile strain capacity typically beyond 3%. This paper presents an investigation on the carbonation behaviour of engineered cementitious composites (ECCs) under coupled sustained flexural load and accelerated carbonation. The carbonation depth under a sustained stress level of 0, 0.075, 0.15, 0.3 and 0.6 relative to flexural strength was measured after 7, 14 and 28 days of accelerated carbonation. Thermogravimetric analysis, mercury intrusion porosimetry and microhardness measurements were carried out to show the coupled influence of sustained flexural load and accelerated carbonation on the changes of the mineral phases, porosity, pore size distribution and microhardness along the carbonation profile. A modified carbonation depth model that can be used to consider the coupled effect of flexural tensile stress and carbonation time was proposed. The results show that an exponential relationship can be observed between stress influence coefficient and flexural tensile stress level in the carbonation depth model of ECC, which is different when using plain concrete. Areas with a higher carbonation degree have greater microhardness, even under a large sustained load level, as the carbonation process refines the pore structure and the fibre bridges the crack effectively.