The relationship between the physicochemical properties (molar volume, partition coefficient, and dissociation constant) of slow-acting systemic postemergence xenobiotics and their uptake and translocation to the sites of action was investigated using the nonlinear, dynamic simulation model ERMESSE. When the pKa was held constant at 4.0, the model enables the prediction of the uptake of a systemic xenobiotic as a function of its partition coefficient and molar volume. The model also considered the effects of the physicochemical properties of a systemic xenobiotic on its long-distance translocation within the vascular tissues. For instance, when the log Kow and pKa were held constant at 1.5 and 6.0, respectively, the model predicted a higher translocation rate (55%) for molecules with a small (e.g., MV = 100 cm3 mol−1) as opposed to a large (e.g., MV = 300 cm3 mol−1, 33%) molar volume. In addition, the theoretical predictions from the ERMESSE model showed that any xenobiotic with a molar volume not exceeding 300 cm3 mol−1 could provide an uptake ?50% and a translocation rate ?25% when its log Kow is between −0.5 and 2.5 and its pKa is between 0.0 and 8.0. 相似文献
There is a growing body of literature showing that physical activity and nature have a positive effect on people's health and well-being. Additionally literature indicates that there may even be a synergic benefit from being physically active whilst simultaneously being directly exposed to nature. This insight is used in recovery programmes for work related stress and mental health care settings. However, as primary care is usually people's first point of contact with the health care system, the greatest benefits for people's health can probably be obtained in primary health care settings. The aim of the present study is therefore to investigate to what extent general practitioners advise patients on physical activity and whether they refer to the additional health benefits of physical activity in a natural environment.
A secondary analysis was performed on a random sample of 2784 video-taped patient consultations of 100 general practitioners in The Netherlands. Many characteristics of these consultations were known on the basis of earlier analyses: diagnosis, age and sex of patient and whether or not the issue of physical activity had been brought up by either patient or doctor. First, we investigated to what extent and with which health problems advice was given concerning physical activity. Second, from these consultations, a stratified sample of 100 consultations was observed in order to investigate whether an advice was given by the general practitioner concerning the additional benefits of nature. In 26% of all consultations advice on physical activity was given by the general practitioner. Physical activity was mentioned more often in cases of vague complaints than in cases with a clear cut diagnosis. As could have been expected, physical activity was mentioned relatively frequently in cases of musculoskeletal complaints and complaints of the nervous system. The additional benefits of physical activity in natural environments was not mentioned during any of the consultations.
In conclusion, general practitioners regularly give advice on physical activity. However, they fail to mention that physical activity in nature areas might have additional health benefits. Given the fact that medical treatment is increasingly evidence based, we think the evidence for the health benefits of physical activity in nature needs to be stronger. Results from such research could eventually find their way into the guidelines of the general practitioners. 相似文献
The aim of this research was to investigate the effect of biochar amendment on soil acidity and other physico‐chemical properties of soil in Southern Ethiopia using a field experiment of three treatments: (1) biochar made of corn cobs, (2) biochar made of chopped Lantana camara stem, and (3) biochar made of Eucalyptus globulus feedstock and a control, in which neither of the biochar was used. Each treatment had three levels of 6, 12 and 18 t ha−1. The experiment was setup with RCBD in a factorial arrangement with three replications. In this regard, a total of 36 plots (each 2 × 2 m size) were applied with three replications to the depth of 0–15cm. From these 36 plots, composite soil samples were collected to the depth of 0–30 cm and analyzed for bulk density, total porosity, pH, soil organic carbon, total nitrogen, available phosphorus, potassium, and exchangeable acidity using standard procedures before and after biochar application. Two‐way ANOVA was also used to analyze the impact of the biochars on soil acidity and other properties. For the treatments that had significant effects, a mean separation was made using Least Significance Difference (LSD) test. The results showed the application of biochar significantly reduced, soil bulk density and exchangeable acidity when compared with a control (p < 0.05). Moreover, the total soil porosity, soil pH, total nitrogen, soil organic carbon, available phosphorus, and potassium were significantly increased in the soil. From among applied biochar treatments, Lantana camara applied at the level of 18 t ha−1 had a higher impact in changing soil physico‐chemical properties. In general, the study suggests that the soil acidity can be reduced by applying biochar as it can amend other soil physico‐chemical properties. 相似文献
