C60 nanotubes have been synthesized by a solution-solution method. After degassing in a dynamic vacuum, the C60 nanotubes doped with alkali metals by means of vapor evaporation method. Different temperatures have been studied to evaporate the alkali metals for the doping experiments. Raman spectrum was further employed to analyze the doping concentration of the obtained samples. It was found that all three alkali metals (Li, Na and K) used can be efficiently doped into the C60 nanotubes, forming AxC60 nanotubes. The doping concentration of Li, Na changed from low to high level, depending on the experiment temperatures, while K doping always gave saturated doping. The melt points, the ionic sizes and vapor pressures of alkali metals were thought to affect the final doping results. 相似文献
ABSTRACT: BACKGROUND: In the 1970s, men in northern Sweden had among the highest prevalences of cardiovascular diseases (CVD) worldwide. An intervention program combining population- and individual-oriented activities was initiated in 1985. Concurrently, collection of information on medical risk factors, lifestyle and anthropometry started. Today, these data make up one of the largest databases in the world on diet intake in a population-based sample, both in terms of sample size and follow-up period. The study examines trends in food and nutrient intake, serum cholesterol and body mass index (BMI) from 1986 to 2010 in northern Sweden. METHODS: Cross-sectional information on self-reported food and nutrient intake and measured body weight, height, and serum cholesterol were compiled for over 140,000 observations. Trends and trend breaks over the 25-year period were evaluated for energy- providing nutrients, foods contributing to fat intake, serum cholesterol and BMI. RESULTS: Reported intake of fat exhibited two significant trend breaks in both sexes: a decrease between 1986 and 1992 and an increase from 2002 (women) or 2004 (men). A reverse trend was noted for carbohydrates, whereas protein intake remained unchanged during the 25-year period. Significant trend breaks in intake of foods contributing to total fat intake were seen. Reported intake of wine increased sharply for both sexes (more so for women) and export beer increased for men. BMI increased continuously for both sexes, whereas serum cholesterol levels decreased during 1986 - 2004, remained unchanged until 2007 and then began to rise. The increase in serum cholesterol coincided with the increase in fat intake, especially with intake of saturated fat and fats for spreading on bread and cooking. CONCLUSIONS: Men and women in northern Sweden decreased their reported fat intake in the first 7 years (1986-1992) of an intervention program. After 2004 fat intake increased sharply for both genders, which coincided with introduction of a positive media support for low carbohydrate-high-fat (LCHF) diet. The decrease and following increase in cholesterol levels occurred simultaneously with the time trends in food selection, whereas a constant increase in BMI remained unaltered. These changes in risk factors may have important effects on primary and secondary prevention of cardiovascular disease (CVD). 相似文献
Protein engineering of the cholera toxin A1 subunit (CTA1) fusedto a dimer of the Ig-binding D-region of Staphylococcus aureusprotein A (DD) was employed to investigate the effect of specificamino acid changes on solubility, stability, enzymatic activityand capacity to act as an adjuvant in vivo. A series of CTA1-DDanalogues were selected by a rational modeling approach, inwhich surface-exposed hydrophobic amino acids of CTA1 were exchangedfor hydrophilic counterparts modeled for best structural fit.Of six different mutants initially produced, two analogues,CTA1Phe132Ser-DD and CTA1Pro185Gln-DD, were demonstrated tohave 50 and 70% increased solubility, respectively, at neutralpH. The double mutant CTA1Phe132Ser/Pro185Gln-DD was at leastthreefold more soluble, demonstrating an additive effect ofthe two mutations. Only the Phe132Ser analogue retained fullbiological activity and stability compared with the native CTA1-DDfusion protein. Two mutants, Pro185Gln and Phe31His mutations,exhibited unaltered ADP-ribosyltransferase activity in vitro,but demonstrated markedly reduced adjuvant function. Since thePro185 and Phe31 amino acids are located in close vicinity onthe distal side of the molecule relative to the enzymaticallyactive cleft, it is conceivable that this region is involvedin mediating a biological function, separate from the enzymaticactivity but intrinsic to the adjuvant activity of CTA1. 相似文献
The role of stories is well established in the traditions of narrative ethics and casuistry. However, from a methodological point of view, the inclusion of fictional works in moral deliberation remains yet unanswered. The paper explains the potential of dystopias for bioethics by means of selected examples and a critical reconstruction and expansion of existing approaches.
Arguments
By means of literary theories, it is proposed to include moral beliefs that motivate dystopias in coherent reflection and reasoning procedures. Furthermore, dystopia’s potential through socioculturally dense scenarios, a contemporary-historical context, and a sensitization to the moral relevance of language for bioethical research are systematically presented.
Conclusion
The methodological considerations provide, on the one hand, practical points of reference for didactic approaches and, on the other hand, for public deliberation. However, the analysis also shows that dystopias introduce their own moral positions beyond a mere illustration or warning.
The infectivity of Trichinella nativa larvae in three traditional northern (country) foods was assessed. Foods were prepared with meat from seals experimentally infected with Trichinella nativa and evaluated over a 317-day period during which this food was fed directly to cats while mice were orally inoculated with larvae recovered following the digestion of the food in a solution containing 1% pepsin and 1% HCl at 37 degrees C. Foods examined were igunaq (meat and blubber placed in a seal skin bag and allowed to ferment), nikku (air-dried meat), and sausage (meat, fillers, salt, and spices). Sausage was examined both in a raw state and after partial cooking. Infective T. nativa larvae survived in igunaq, nikku, raw frozen sausage, and poorly cooked sausage for at least 5 months under controlled laboratory conditions. Core temperatures of partially cooked sausage never exceeded 50 degrees C. Caution should be exercised in using these data to establish guidelines for the consumption of raw products, since the survival of infective larvae could be unpredictably extended under field conditions. These data indicate significant food safety risks associated with igunaq, nikku, and sausage prepared with Trichinella-infected meat and provide information for use in risk management and in directing future research. 相似文献
This paper reports the first stage of work being undertaken to understand the factors that have impacted on the current state of food safety in the UK food manufacturing sector. The paper first explores developments in international food safety regulation in general and in particular, the UK. Using a survey and case study methodology, the paper examines the response of food manufacturing enterprises to food safety regulation, and uses statistical techniques to investigate the effects of enterprise size on the drivers for, benefits of, and challenges to compliance. Further, the factors that influence the successful implementation of an integrated food safety management system are also examined. The results show a great deal of both statutory and private regulation that has incentivised enterprises. In response, enterprises have implemented integrated food safety management systems to proactively deal with the risks associated with food safety, however, enterprises claim that statutory regulations are biased towards consumers, without adequate impact assessments on all stakeholders within the chain, and hence causing industry to incur significant costs that could otherwise be avoided. Even though compliance with food safety regulation is burdensome, the cost of non-compliance will also be significant to enterprises. The findings also show that there is no significant effect of size of enterprise on the drivers, benefits and challenges to compliance with food safety regulation. 相似文献
A number of pure refractory metals have been investigated by drop-tube experiments. The cooling curves have been registered and theoretically analysed. A model for analysing the heat of fusion has been developed. It was found that the heat of fusion was approximately 50% of the tabulated value. 相似文献
We continue the study of cellular automata (CA) directional dynamics, i.e. , the behavior of the joint action of CA and shift maps. This notion has been investigated for general CA in the case of expansive dynamics by Boyle and Lind; and by Sablik for sensitivity and equicontinuity. In this paper we give a detailed classification for the class of additive CA providing non-trivial examples for some classes of Sablik’s classification. Moreover, we extend the directional dynamics studies by considering also factor languages and attractors. 相似文献
Musculoskeletal disorders are more common among women than among men. When comparing the difference between men and women in the prevalence of musculoskeletal disorders, methodological problems arise as men and women seldom perform the same type of activities, neither at work nor at home.
The main objective of this cross-sectional case study was to compare work technique and self-reported musculoskeletal symptoms between men and women performing the same type of work tasks within a metal industry. Other factors, such as leisure activities, were also taken into consideration. Three data collection methods were used; questionnaire, interviews and systematic observations. The results from the observations revealed that women worked more frequently and during longer times with their hands above shoulder height than men. Working with hands above shoulder height is considered a risk factor for neck and shoulder disorders according to previous studies. Workplace design factors were probably a reason for differences in working technique between men and women. A higher proportion of women than men reported shoulder symptoms. Women spent more time on household activities than men, which indicates a higher total workload in paid and unpaid work. 相似文献