Personality factors related to shift work tolerance in two- and three-shift workers

This study aimed to investigate whether different personality variables were associated with shift work tolerance, and whether these potential associations were moderated by various types of shift work. The sample comprised 1505 nurses who worked either two or three rotating shifts. Personality traits were measured in terms of morningness, flexibility, languidity and hardiness. Morningness reflects the tendency to be alert relatively early in the morning and sleepy relatively early in the evening. Flexibility denotes the ability to both work and sleep at odd times of the day, while languidity concerns the tendency to become tired/sleepy when cutting down on sleep. Hardiness relates to resilience to stressful life events. The dependent variables in this study comprised of measures of insomnia, sleepiness, depression and anxiety. Hierarchical regression analyses, which controlled for demographic variables and work load, revealed that Morningness was significantly and negatively related to insomnia. The Morningness by Shift type interaction was overall significant for depressive symptoms. Morningness was near significantly associated with lower levels of depressive symptoms in three-shift workers, but unrelated to depressive symptoms in two-shift workers. Flexibility was associated with higher levels of depressive symptoms. Flexibility by Shift type interaction was significant for insomnia, indicating that flexibility was negatively associated with insomnia for three-shift workers and unrelated with insomnia for two-shift workers. Languidity was associated with higher levels of sleepiness, depressive and anxiety symptoms. Hardiness was associated with lower levels of all four dependent variables.     

Dietary composition in Greenland 2000, plasma fatty acids and persistent organic pollutants

Human exposure to pollution in the Arctic presents a potential future health risk for the local populations. Epidemiological studies in Greenland have shown that human blood levels of several organic contaminants are very high, especially in the North where people depend on local food. In East Greenland (Ittoqqortoormiit (Scoresbysund)) the population shows the highest blood levels of several persistent organic pollutants found in Arctic countries, especially PCB, the levels of which exceed Canadian guideline levels. As in other Arctic countries, the direct source of these contaminants is the diet, and it is, therefore important to monitor the composition of the diet along with other factors which may influence the metabolism and thereby the accumulation of toxic substances. This project is part of the human health program of the ongoing circumpolar 'Arctic Monitoring and Assessment Programme'. Dietary survey results (Semiquantitative Food Frequency questionnaire from 192 men and women from East Greenland and 48 men from Uummannaq West Greenland) were analysed along with other factors (lifestyle and anthropometric factors), blood lipids, fatty acid profiles, and concentrations of persistent organic pollutants (POPs). The dietary survey showed that the contributions of traditional food provided 25-30% of the total energy intake. However, the relative monthly meal intake of seal, whale, polar bear, fish and game, and the composition of imported food, varied between districts. The blood fatty acids (FA), e.g. the n-3/n-6 ratio (Uummannaq 0.70, Ittoqqortoormiit 0.37 Tassiilaq 0.45) showed moderate associations with the overall reported food composition. The n-3 fatty acids were associated with the well-known lowering effect on serum-triglyceride levels. The strongest associations between diet and plasma fatty acids were found for docosapentaenoic acid, C: 22.5.3 which strongly correlated with reported seal, and polar bear intake (P=0.01** and 0.04*, respectively), consistent with the fact that seal and polar bear blubber contain much higher concentrations of C: 22.5.3 than other sea mammals and fish. Seal and polar bear intake, and in particular all the plasma n-3 fatty acids, were significantly correlated with organic contaminant concentrations, (betaHCH, chlordanes, DDTs, Hexachlorobenzene, Mirex, PCBs, and toxaphenes) P<0.01**. CONCLUSIONS: The strongest correlations between POPs and fatty acids were found with C: 22.5.3, strongly indicating seal and polar bear blubber as the main contributors of POPs to the local population.     

The hardwater effect in AMS 14C dating of food crusts on pottery

The pottery investigated in this study comes from late mesolithic inland sites next to rivers in Northern Germany. The first AMS ¹⁴C datings of food crusts from these sites showed surprisingly high ages, which could be caused by the hardwater effect.Modern samples from the rivers have ages of several hundred ¹⁴C years, and a modern food crust prepared from fish with a certain reservoir age shows the same age as the fish. Surprisingly, there was a large age difference between water samples and fish/mollusc shell from the same river. Associated archaeological samples of terrestrial and fluvial origin show age differences of several hundred and up to 3000 years. These high age differences are only to a limited extent transferred to the archaeological food crusts.     

Dietary Linoleic Acid Elevates the Endocannabinoids 2-AG and Anandamide and Promotes Weight Gain in Mice Fed a Low Fat Diet

Dietary intake of linoleic acid (LNA, 18:2n-6) has increased dramatically during the 20th century and is associated with greater prevalence of obesity. The endocannabinoid system is involved in regulation of energy balance and a sustained hyperactivity of the endocannabinoid system may contribute to obesity. Arachidonic acid (ARA, 20:4n-6) is the precursor for 2-AG and anandamide (AEA), and we sought to determine if low fat diets (LFD) could be made obesogenic by increasing the endocannabinoid precursor pool of ARA, causing excessive endocannabinoid signaling leading to weight gain and a metabolic profile associated with obesity. Mice (C57BL/6j, 6 weeks of age) were fed 1 en% LNA and 8 en% LNA in low fat (12.5 en%) and medium fat diets (MFD, 35 en%) for 16 weeks. We found that increasing dietary LNA from 1 to 8 en% in LFD and MFD significantly increased ARA in phospholipids (ARA–PL), elevated 2-AG and AEA in liver, elevated plasma leptin, and resulted in larger adipocytes and more macrophage infiltration in adipose tissue. In LFD, dietary LNA of 8 en% increased feed efficiency and caused greater weight gain than in an isocaloric reduction to 1 en% LNA. Increasing dietary LNA from 1 to 8 en% elevates liver endocannabinoid levels and increases the risk of developing obesity. Thus a high dietary content of LNA (8 en%) increases the adipogenic properties of a low fat diet.     

Traditional and modern Greenlandic food - dietary composition, nutrients and contaminants

OBJECTIVES: High levels of n-3 fatty acids and other nutrients in traditional Inuit food appear to provide some protection against the typical diseases of affluent industrialized societies: cardiovascular diseases and type 2 diabetes. An increased intake of imported food among Inuits will probably increase their frequency of these diseases. However, since the 1970s it has become evident that the marine-based Inuit diet also contains high levels of potentially toxic lipophilic organic pollutants and heavy metals. Since these two food related opposing health effects appear to be inseparable, the phenomenon has been known as "The Arctic Dilemma". However, both the fatty acid composition and the contaminant levels vary in Greenlandic food items. Thus in principle it is possible to compose a diet where the benefits and risks are better balanced. Our objectives of this study were to compare traditional and modern meals in Greenland concerning the dietary composition, nutrients, and health indicators among the consumers. STUDY DESIGN: The present study was a cross-sectional dietary survey as part of the Arctic Monitoring and Assessment, Human Health Programme (AMAP). These results were compared with older dietary surveys in Greenland. METHODS: Dietary components, fatty acids, and nutrients in 90 local meals collected by duplicate portion method in Uummannaq town, north Greenland 2004 and in Narsaq, south Greenland 2006, were compared with 177 duplicate meals sampled in the village of Igdslorsuit, Uummannaq, district, 1976 and also compared with other dietary studies in Greenland 1953-1987. Anthropometric measures (weight, height, and body mass index, BMI) and blood lipids were measured as health indicators among the participants. RESULTS: Between the traditional foods sampled or analysed 30-50 years ago and the modern food from 2004 to 2006, significant differences were found in the dietary composition. The percentage of local food had decreased, to a present average of about 20% and with it the dietary content of n-3 fatty acids. Also, the intakes of many vitamins and minerals had decreased, and were below Nordic Nutrient Recommendations in 2004 and 2006. Vitamin A, B(1), (B(2)), B(12), iron, iodine, phosphorus, and selenium contents were correlated with n-3 content, whereas vitamin C, folate, and calcium contents were not and the same time very low. In the traditional food, especially from the villages, the intakes of vitamin A, vitamin D, and iron were extremely high and borderline toxic. The levels of contaminants such as organochlorins and heavy metals were also strongly correlated with the relative content of local food in the diet. The best balance between potentially beneficial and harmful substances was found for 20-30% local food, corresponding to a daily intake of 3-5 g of n-3 fatty acids. Body weight, height, body mass index (BMI), cholesterol, and S-triglycerides had increased significantly between 1976 and 2004. CONCLUSION: The dietary changes to a more western fare were found to be negative resulting in less adequate nutrient coverage but at the same time lower contaminant load. Thus, we recommend not to increase the consumption of local products beyond the present level but rather to improve the quality of the imported food.     

Gain measurements of Fabry-Perot InP/InGaAsP lasers using an ultrahigh-resolution spectrometer

Measurements of the optical gain in a semiconductor laser using a 20 MHz resolution optical spectrum analyzer are presented for what is believed to be the first time. The high resolution allows for accurate gain measurements close to the lasing threshold. This is demonstrated by gain measurements on a bulk InGaAsP 1.5 microm Fabry-Perot laser. Combined with direct measurement of transparency carrier density values, parameters were determined for characterizing the gain at a range of wavelengths and temperatures. The necessity of the use of a logarithmic gain model is shown.     

Discovery of Ligands for the Human Intestinal Di‐/Tripeptide Transporter (hPEPT1) Using a QSAR‐Assisted Virtual Screening Strategy

The discovery of novel ligands for the hPEPT1 transporter is reported. By exploiting a fast and rigorously validated QSAR model in combination with the distance in activity‐centered chemical space (DACCS) approach, a database of commercially available compounds (Sigma–Aldrich) was screened for virtual hits. Twelve compounds were then purchased and characterized in an apical [¹⁴C]Gly‐Sar uptake competition assay. Four compounds displayed affinity in the medium‐to‐high range. A simple benzophenone derivative displayed high affinity with a sub‐millimolar binding constant (K_i=0.24 mM ). The results of this study will serve as starting points for future projects, including the design and synthesis of compound libraries that seek to systematically explore the fundamental requirements for binding and transport by hPEPT1.     

Fabrication of bulk materials from fine particles of PbTe-SnTe solid solutions prepared through thermal decomposition of salts

A process has been proposed for the fabrication of microcrystalline thermoelectric materials based on PbTe-SnTe solid solutions by compacting and hot-pressing fine powders prepared through the thermal decomposition of lead acetate trihydrate and tin oxalate in the presence of tellurium powders. We analyze the mechanism of the thermal decomposition of the powder mixtures, resulting in the formation of Pb_{1 − x} Sn _x Te particles, and examine the influence of cold compaction, heat treatment, and hot pressing on the grain composition, electrical conductivity, and Seebeck coefficient of materials prepared by pressing the powders.