416 research outputs found
Self-Induced Quasistationary Magnetic Fields
The interaction of electromagnetic radiation with temporally dispersive
magnetic solids of small dimensions may show very special resonant behaviors.
The internal fields of such samples are characterized by
magnetostatic-potential scalar wave functions. The oscillating modes have the
energy orthogonality properties and unusual pseudo-electric (gauge) fields.
Because of a phase factor, that makes the states single valued, a persistent
magnetic current exists. This leads to appearance of an eigen-electric moment
of a small disk sample. One of the intriguing features of the mode fields is
dynamical symmetry breaking
Sodium and potassium intake patterns and trends in South Korea
We examined major trends and patterns regarding sodium and potassium intake and the ratio of sodium and potassium in the diets of South Koreans. We analyzed detailed 24-hour dietary recall data collected from 10,267; 8,819; and 9,264 subjects ages two years and older in the 1998, 2005, and 2009 Korean National Health and Nutrition Examination Surveys, respectively. Mean sodium intake did not change significantly between 1998 and 2009 (4.6 g/d vs 4.7 g/d), while potassium intake increased significantly [2.6 g/d vs. 2.9 g/d (p < 0.001)]. The major dietary sodium sources were kimchi, salt, soy sauce, and soybean paste, and most potassium came from unprocessed foods (white rice, vegetables, kimchi, and fruits). About 50 percent of the participants consumed 4 or more grams of sodium per capita per day. The proportion of respondents consuming 4 to 6 grams of potassium per capita per day increased from 10.3 percent in 1998 to 14.3 percent in 2009 (p < 0.001), and the sodium-potassium ratio decreased from 1.88 to 1.71 (p < 0.001). One major implication is that efforts to reduce sodium in processed foods will be ineffective and future efforts must focus on both education to reduce use of sodium in food preparation and sodium replacement in salt, possibly with potassium
The relationship between family and child weight status by household structure in South Korea: 2007–2010
Objective:Parental obesity has been identified as a predominant risk factor for childhood overweight and obesity. We investigated the relationship between parent and child obesity in South Korea, particularly linked with varying family structures.Subjects and methods:Data for households with children aged 2–18 years were taken from the pooled data of the Korea National Health and Nutrition Examination Survey (KNHANES) 2007–2010 conducted by the Korea Centers for Disease Control and Prevention (KCDC). The sample consisted of 17 453 individuals (7879 children and 9574 adults) from 5048 households with children for this study. Children's overweight and obesity prevalence was compared using both International Obesity Taskforce (IOTF) and KCDC cutoff points according to parental weight status and household structure. Logistic regression analysis was used.Results:Significantly greater odds of overweight and obesity existed among children living with both parents (odds ratio (OR)=3.5, 95% confidence interval (CI): 2.71, 4.65) or one parent (mother: OR=1.6, 95% CI: 1.22, 2.12; father: OR=1.7, 95% CI: 1.37, 1.99). The adjusted ORs for overweight and obesity among children living with overweight mother only or overweight grandparent only were approximately double that of children living with normal-weight mother (OR=2.2, 95% CI: 1.22–3.82) or normal-weight grandparent (OR=2.1, 95% CI: 1.06–4.05).Conclusion:Children living with overweight parent(s) or grandparent(s) were positively correlated with the risk for childhood overweight and obesity. Socioeconomic status did not affect the observed relationships in this population, whereas the role of genetic, dietary and activity patterns requires further exploration
The Parasite Reduction Ratio (PRR) assay version 2: standardized assessment of Plasmodium falciparum viability after antimalarial treatment in vitro
With artemisinin-resistant Plasmodium falciparum parasites emerging in Africa, the need for new antimalarial chemotypes is persistently high. The ideal pharmacodynamic parameters of a candidate drug are a rapid onset of action and a fast rate of parasite killing or clearance. To determine these parameters, it is essential to discriminate viable from nonviable parasites, which is complicated by the fact that viable parasites can be metabolically inactive, whilst dying parasites can still be metabolically active and morphologically unaffected. Standard growth inhibition assays, read out via microscopy or [3H] hypoxanthine incorporation, cannot reliably discriminate between viable and nonviable parasites. Conversely, the in vitro parasite reduction ratio (PRR) assay is able to measure viable parasites with high sensitivity. It provides valuable pharmacodynamic parameters, such as PRR, 99.9% parasite clearance time (PCT99.9%) and lag phase. Here we report the development of the PRR assay version 2 (V2), which comes with a shorter assay duration, optimized quality controls and an objective, automated analysis pipeline that systematically estimates PRR, PCT99.9% and lag time and returns meaningful secondary parameters such as the maximal killing rate of a drug (Emax) at the assayed concentration. These parameters can be fed directly into pharmacokinetic/pharmacodynamic models, hence aiding and standardizing lead selection, optimization, and dose prediction. © 2023 by the authors
Takeaway meal consumption and risk markers for coronary heart disease, type 2 diabetes and obesity in children aged 9-10 years: a cross-sectional study.
OBJECTIVE: To investigate associations between takeaway meal consumption and risk markers for coronary heart disease, type 2 diabetes and obesity risk markers in children. DESIGN: A cross-sectional, school-based observational study. SETTING: 85 primary schools across London, Birmingham and Leicester. PARTICIPANTS: 1948 UK primary school children in year 5, aged 9-10 years. MAIN OUTCOME MEASURES: Children reported their frequency of takeaway meal consumption, completed a 24-hour dietary recall, had physical measurements and provided a fasting blood sample. RESULTS: Among 1948 participants with complete data, 499 (26%) never/hardly ever consumed a takeaway meal, 894 (46%) did so <1/week and 555 (28%) did ≥1/week. In models adjusted for age, sex, month, school, ethnicity and socioeconomic status, more frequent takeaway meal consumption was associated with higher dietary intakes of energy, fat % energy and saturated fat % energy and higher energy density (all P trend <0.001) and lower starch, protein and micronutrient intakes (all P trend <0.05). A higher frequency of takeaway meal consumption was associated with higher serum total cholesterol and low-density lipoprotein (LDL) cholesterol (P trend=0.04, 0.01, respectively); children eating a takeaway meal ≥1/week had total cholesterol and LDL cholesterol 0.09 mmol/L (95% CI 0.01 to 0.18) and 0.10 mmol/L (95% CI 0.02 to 0.18) higher respectively than children never/hardly ever eating a takeaway meal; their fat mass index was also higher. CONCLUSIONS: More frequent takeaway meal consumption in children was associated with unhealthy dietary nutrient intake patterns and potentially with adverse longer term consequences for obesity and coronary heart disease risk
Energy Density, Portion Size, and Eating Occasions: Contributions to Increased Energy Intake in the United States, 1977–2006
Using data from three surveys, Kiyah Duffey and Barry Popkin found that changes in eating/drinking occasions and portion size consistently account for most of the change in daily total energy intake over a 30-year period
The lifetime of nitrogen oxides in an isoprene-dominated forest
The lifetime of nitrogen oxides (NO_x) affects the concentration and distribution of NO_x and the spatial patterns of nitrogen deposition. Despite its importance, the lifetime of NO_x is poorly constrained in rural and remote continental regions. We use measurements from a site in central Alabama during the Southern Oxidant and Aerosol Study (SOAS) in summer 2013 to provide new insights into the chemistry of NO_x and NO_x reservoirs. We find that the lifetime of NO_x during the daytime is controlled primarily by the production and loss of alkyl and multifunctional nitrates (ΣANs). During SOAS, ΣAN production was rapid, averaging 90 ppt h^(−1) during the day, and occurred predominantly during isoprene oxidation. Analysis of the ΣAN and HNO_3 budgets indicate that ΣANs have an average lifetime of under 2 h, and that approximately 45 % of the ΣANs produced at this site are rapidly hydrolyzed to produce nitric acid. We find that ΣAN hydrolysis is the largest source of HNO_3 and the primary pathway to permanent removal of NO_x from the boundary layer in this location. Using these new constraints on the fate of ΣANs, we find that the NO_x lifetime is 11 ± 5 h under typical midday conditions. The lifetime is extended by storage of NO_x in temporary reservoirs, including acyl peroxy nitrates and ΣANs
Organic nitrate aerosol formation via NO_3 + biogenic volatile organic compounds in the southeastern United States
Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOCs) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that a nitrate radical (NO_3) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO_3 to terpenes are correlated with increase in gas- and aerosol-organic nitrate concentrations made during the campaign. Correlation of NO_3 radical consumption to organic nitrate aerosol formation as measured by aerosol mass spectrometry and thermal dissociation laser-induced fluorescence suggests a molar yield of aerosol-phase monoterpene nitrates of 23–44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to BVOCs and show C_(10)H_(17)NO_5, likely a hydroperoxy nitrate, is a major nitrate-oxidized terpene product being incorporated into aerosols. The comparable isoprene product C_5H_9NO_5 was observed to contribute less than 1 % of the total organic nitrate in the aerosol phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO_3 uptake produced nitrate aerosol mass loading at a rate comparable to that of organic nitrate produced via NO_3 + BVOCs
Fertilization with beneficial microorganisms decreases tomato defenses against insect pests
International audienceThe adverse effects of chemical fertilizers on agricultural fields and the environment are compelling society to move toward more sustainable farming techniques. “Effective microorganisms” is a beneficial microbial mixture that has been developed to improve soil quality and crop yield while simultaneously dramatically reducing organic chemical application. Additional indirect benefits of beneficial microorganisms application may include increased plant resistance to herbivore attack, though this has never been tested till now. Tomato plants were grown in controlled greenhouse conditions in a full-factorial design with beneficial microorganisms inoculation and commercial chemical fertilizer application as main factors. We measured plant yield and growth parameters, as well as resistance against the generalist pest Spodoptera littoralis moth larval attack. Additionally, we measured plant defensive chemistry to underpin resistance mechanisms. Overall, we found that, comparable to chemical fertilizer, beneficial microorganisms increased plant growth fruit production by 35 and 61 %, respectively. Contrary to expectations, plants inoculated with beneficial microorganisms sustained 25 % higher insect survival and larvae were in average 41 % heavier than on unfertilized plants. We explain these results by showing that beneficial microorganism-inoculated plants were impaired in the induction of the toxic glycoalkaloid molecule tomatine and the defense-related phytohormone jasmonic acid after herbivore attack. For the first time, we therefore show that biofertilizer application might endure unintended, pest-mediated negative effects, and we thus suggest that biofertilizer companies should incorporate protection attributes in their studies prior to commercialization
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