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Sample records for affect nutrient delivery

  1. Factors affecting plant growth in membrane nutrient delivery

    NASA Technical Reports Server (NTRS)

    Dreschel, T. W.; Wheeler, R. M.; Sager, J. C.; Knott, W. M.

    1990-01-01

    The development of the tubular membrane plant growth unit for the delivery of water and nutrients to roots in microgravity has recently focused on measuring the effects of changes in physical variables controlling solution availability to the plants. Significant effects of membrane pore size and the negative pressure used to contain the solution were demonstrated. Generally, wheat grew better in units with a larger pore size but equal negative pressure and in units with the same pore size but less negative pressure. Lettuce also exhibited better plant growth at less negative pressure.

  2. Porous tube plant nutrient delivery system development: A device for nutrient delivery in microgravity

    NASA Technical Reports Server (NTRS)

    Dreschel, T. W.; Brown, C. S.; Piastuch, W. C.; Hinkle, C. R.; Knott, W. M.

    1994-01-01

    The Porous Tube Plant Nutrient Delivery Systems or PTPNDS (U.S. Patent #4,926,585) has been under development for the past six years with the goal of providing a means for culturing plants in microgravity, specifically providing water and nutrients to the roots. Direct applications of the PTPNDS include plant space biology investigations on the Space Shuttle and plant research for life support in the Space Station Freedom. In the past, we investigated various configurations, the suitability of different porous materials, and the effects of pressure and pore size on plant growth. Current work is focused on characterizing the physical operation of the system, examining the effects of solution aeration, and developing prototype configurations for the Plant Growth Unit (PGU), the flight system for the Shuttle mid-deck. Future developments will involve testing on KC-135 parabolic flights, the design of flight hardware and testing aboard the Space Shuttle.

  3. Nutrients affecting brain composition and behavior

    NASA Technical Reports Server (NTRS)

    Wurtman, R. J.

    1987-01-01

    This review examines the changes in brain composition and in various brain functions, including behavior, that can follow the ingestion of particular foods or nutrients. It details those that are best understood: the increases in serotonin, catecholamine, or acetylcholine synthesis that can occur subsequent to food-induced increases in brain levels of tryptophan, tyrosine, or choline; it also discusses the various processes that must intervene between the mouth and the synapse, so to speak, in order for a nutrient to affect neurotransmission, and it speculates as to additional brain chemicals that may ultimately be found to be affected by changes in the availability of their nutrient precursors. Because the brain chemicals best known to be nutrient dependent overlap with those thought to underlie the actions of most of the drugs used to treat psychiatric diseases, knowledge of this dependence may help the psychiatrist to understand some of the pathologic processes occurring in his/her patients, particularly those with appetitive symptoms. At the very least, such knowledge should provide the psychiatrist with objective criteria for judging when to take seriously assertions that particular foods or nutrients do indeed affect behavior (e.g., in hyperactive children). If the food can be shown to alter neurotransmitter release, it may be behaviorally-active; however, if it lacks a discernible neurochemical effect, the likelihood that it really alters behavior is small.

  4. Porous membrane utilization in plant nutrient delivery

    NASA Technical Reports Server (NTRS)

    Dreschel, T. W.; Hinkle, C. R.; Prince, R. P.; Knott, W. M., III

    1987-01-01

    A spacecraft hydroponic plant growth unit of tubular configuration, employing a microporous membrane as a capilary interface between plant roots and a nutrient solution, is presented. All three of the experimental trials undertaken successfully grew wheat from seed to harvest. Attention is given to the mass/seed, number of seeds/head, ratio of seed dry mass to total plant dry mass, production of tillers, and mass of seed/plant. Dry matter production is found to be reduced with increasing suction pressure; this is true for both average seed and average total dry matter/plant. This may be due to a reduction in water and nutrient availability through the microporous membrane.

  5. Influence of nutrient delivery on gut structure and function.

    PubMed

    Bragg, L E; Thompson, J S; Rikkers, L F

    1991-01-01

    Food is an important stimulus for the growth of gastrointestinal mucosa. Gut structure is influenced by the route of nutrient administration, dietary composition and the availability of specific nutrients. The alterations in intestinal structure and function that occur when enteral nutrition is withheld suggests that the ingestion of food results in physiologic responses that are responsible for the maintenance of gut mass during the fed state. The mechanism of mucosal suppression that occurs during starvation, stress, and total parenteral nutrition is not completely understood but may involve the absence of luminal substrates, decreased pancreaticobiliary secretions and alterations in the endocrine or paracrine events that normally accompany eating, digestion, and absorption. Enterocytes prefer glutamine and ketone bodies as oxidative fuels, whereas colonocytes utilize short chain fatty acids. Although enteral delivery of nutrients is the preferred route for maintenance of intestinal mass, provision of specific nutrients and hormonal stimulation during parenteral alimentation has been shown to be important in maintaining mucosal structure and function. If not adequately maintained, the intestine becomes susceptible to a variety of injuries which may result in impaired ability to digest and absorb nutrients and loss of mucosal barrier function.

  6. Biofortification of crops with nutrients: factors affecting utilization and storage.

    PubMed

    Díaz-Gómez, Joana; Twyman, Richard M; Zhu, Changfu; Farré, Gemma; Serrano, José Ce; Portero-Otin, Manuel; Muñoz, Pilar; Sandmann, Gerhard; Capell, Teresa; Christou, Paul

    2017-01-06

    Biofortification is an effective and economical method to improve the micronutrient content of crops, particularly staples that sustain human populations in developing countries. Whereas conventional fortification requires artificial additives, biofortification involves the synthesis or accumulation of nutrients by plants at source. Little is known about the relative merits of biofortification and artificial fortification in terms of nutrient bioaccessibility and bioavailability, and much depends on the biochemical nature of the nutrient, which can promote or delay uptake, and determine how efficiently different nutrients are transported through the blood, stored, and utilized. Data from the first plants biofortified with minerals and vitamins provide evidence that the way in which nutrients are presented can affect how they are processed and utilized in the human body. The latest studies on the effects of the food matrix, processing and storage on nutrient transfer from biofortified crops are reviewed, as well as current knowledge about nutrient absorption and utilization.

  7. Exploited and excreting: parasite type affects host nutrient recycling.

    PubMed

    Narr, Charlotte F; Frost, Paul C

    2016-08-01

    Parasite-induced changes in the nutrient balance of hosts could alter the availability of nutrients in ecosystems by changing consumer-driven nutrient recycling. While these effects on host nutrient use are mediated by host physiology, they likely depend on characteristics of the parasite and host diet quality. We examined this possibility by measuring nutrient release rates of uninfected Daphnia and conspecifics infected by two microparasites (the bacterium Pasteuria ramosa and the microsporidium Hamiltosporidium tvaerminnensis) from daphnid hosts fed food that varied in phosphorus content. We found that infection type and diet affected host nutrient release rates, but the strength of these effects varied among parasite treatments. To improve our understanding of these effects, we examined whether two separate aspects of host exploitation (parasite-induced reductions in host fecundity and parasite load) could account for variation in Daphnia nutrient release, ingestion, and elemental ratios caused by our infection and diet treatments. Regardless of whether we compared individuals across infection type or diet treatment, Daphnia fecundity described variation in multiple aspects of host nutrient use better than infection, diet, or spore load. Our results suggest that parasite-induced changes in host nutrient use are both parasite and diet specific, and that host fecundity could be a useful parameter for predicting the magnitude and direction of these changes.

  8. [Principle demonstration of nutrient delivery system in a space vegetable planting prototype facility].

    PubMed

    Guo, S S; Xu, B; Ai, W D; Wang, K; Liu, X Y; Wang, P X

    2001-06-01

    Objective. To develop a nutrient delivery system for space vegetable planting prototype facility to be used in future space station, and to preliminarily testify its feasibility through ground-based demonstration experiments. Method. A nutrient delivery system in a space vegetable planting prototype facility was designed and fabricated, and ground based demonstration experiments of plant cultivation were conducted. Result. Nutrient could be steadily delivered to plant cultivation matrixes through capillary action, water content of planting matrixes could be controlled automatically and maintained constant, and the planted material lettuce showed basically normal morphology and color. Conclusion. The nutrient delivery system in a space vegetable planting prototype facility could basically meet the requirements for plant nutrient delivery under space microgravity environmental condition.

  9. HYDRAULIC FRACTURING TO IMPROVE NUTRIENT AND OXYGEN DELIVERY FOR IN SITU BIORECLAMATION

    EPA Science Inventory

    The in situ delivery of nutrients and oxygen in soil is a serious problem in implementing in situ biodegradation. Current technology requires ideal site conditions to provide the remediating organisms with the nutrients and oxygen required for their metabolism, but...

  10. Mechanisms linking employee affective delivery and customer behavioral intentions.

    PubMed

    Tsai, Wei-Chi; Huang, Yin-Mei

    2002-10-01

    Past empirical evidence has indicated that employee affective delivery can influence customer reactions (e.g., customer satisfaction, service quality evaluation). This study extends previous research by empirically examining mediating processes underlying the relationship between employee affective delivery and customer behavioral intentions. Data were collected from 352 employee-customer pairs in 169 retail shoe stores in Taiwan. Results showed that the influence of employee affective delivery on customers' willingness to return to the store and pass positive comments to friends was indirect through the mediating processes of customer in-store positive moods and perceived friendliness. The study also indicated that employee affective delivery influences customers' time spent in store, which, in turn, influences customer behavioral intentions.

  11. Do rivermouths alter nutrient and seston delivery to the nearshore?

    USGS Publications Warehouse

    Larson, James H.; Frost, Paul C.; Vallazza, Jon M.; Nelson, John; Richardson, William B.

    2016-01-01

    Tributary inputs to lakes and seas are often measured at riverine gages, upstream of lentic influence. Between these riverine gages and the nearshore zones of large waterbodies lie rivermouths, which may retain, transform and contribute materials to the nearshore zone. However, the magnitude and timing of these rivermouth effects have rarely been measured.During the summer of 2011, 23 tributary systems of the Laurentian Great Lakes were sampled from river to nearshore for dissolved and particulate carbon (C), nitrogen (N) and phosphorus (P) concentrations, as well as bulk seston and chlorophyll a concentrations. Three locations per system were sampled: in the upstream river, in the nearshore zone and at the outflow from the rivermouth to the lake. Using stable oxygen isotopes, a water-mixing model was developed to estimate the nutrient concentration that would occur at the rivermouth if mixing was strictly conservative (i.e. if no processing occurred within the rivermouth). Deviations between these conservative mixing estimates and measured nutrient concentrations were identified as rivermouth effects on nutrient concentrations.Rivermouths had higher concentration of C and P than nearshore areas and more chlorophyll athan upstream river waters. Compared to the conservative mixing model, rivermouths as a class appeared to be summer-time sources of N, P and chlorophyll a. Substantial among rivermouth variation occurred both in the effect size and direction for all constituents.Using principal component analysis, two groups of rivermouths were identified: rivermouths that had a large effect on most constituents and those that had very little effect on any of the measured constituents. ‘High-effect’ rivermouths had more abundant upstream croplands, which were presumably the sources of inorganic nutrients. Cross-validated models built using characteristics of the rivermouth were not good predictors of variation in rivermouth effects on most constituents

  12. Do rivermouths alter nutrient and seston delivery to the nearshore?

    USGS Publications Warehouse

    Larson, James H.; Richardson, William B.

    2016-01-01

    Tributary inputs to lakes and seas are measured at riverine gages, upstream of lentic influence. Between these riverine gages and the nearshore zones of large waterbodies lie rivermouths, which may retain, transform and contribute materials to the nearshore zone. During the summer of 2011, twenty-three tributary systems of the Laurentian Great Lakes were sampled from river to nearshore for dissolved and particulate carbon (C), nitrogen (N) and phosphorus (P) concentrations, as well as bulk seston and chlorohyll a concentrations. Rivermouths had higher concentrations of C and P than nearshore areas and more chlorophyll a than upstream river waters. Compared to a conservative mixing model, rivermouths as a class appeared to be summer-time sources of N, P and chlorophyll a. Substantial among-rivermouth variation occurred both in the effect size and direction for all constituents. Using principal components analysis, two groups of rivermouths were apparent. Rivermouths that had a large effect on most constituents, or those that had very little effect on any of the measured constituents. “High-effect” rivermouths had more abundant upstream croplands, presumably reflecting greater sources of inorganic nutrients. Cross-validated models built using characteristics of the rivermouth were not good predictors of variation in rivermouth effects on most constituents. For filter feeding consumers and microbes directly taking up dissolved nutrients, rivermouths are more resource-rich than upstream riverine or nearby lake waters. Given declines over time in open lake productivity within the Great Lakes, rivermouths may contribute more productivity than their size would suggest to the Great Lakes food web.

  13. The Coupling of Solution Chemistry to Plant Nutrient Demand in an on Demand Nutrient Delivery System

    NASA Technical Reports Server (NTRS)

    Savage, Wayne

    1998-01-01

    The goal of the proposal will be to determine the suitability of the DASI instrument in providing a signal that can be recognized and be utilized as an indicator of plant stress. The method to be utilized for evaluating stress is the presentation of an every increasing level of nutrient deficiency and salinity stress (addition of salt (NACl) or increasing concentration of balanced nutrient) while simultaneously recording spectral reflectance using the DASI instrument and monitoring the traditional processes of gas exchange and nutrient uptake parameters. In this manner, we will be able to directly compare the DASI measurements with known stresses as determined by the traditional gas exchange and nutrient uptake measures of stress. We anticipate that the DASI will provide a sensitive identifier of plant stress; recording signals of the resulting changes in plant metabolism in real time, far before any visible effects of stress could be observed. Thus, there is a potential for very early management intervention to correct a stress condition before damage could develop. The present response time for the observation of visual symptoms of plant stress is considerable and only provides an indication that a stress is present after it has been present for an extended period of time. Thus, the impact of a plant-based life support function will have already been significant. An additional benefit of this research to regenerative life support will be the characterization of a potential recovery scenario from various degrees of stress. The experimental approach to be employed includes the removal of the stress at various points in the stress gradient and the characterization of plant performance and reflectance spectra during recovery from various degrees of stress. Spectral reflectance imaging techniques have been developed and used to measure the biochemical composition of plants and relate these characteristics to the fluxes of biochemical elements within the ecosystem.

  14. The optimal mode of delivery for the haemophilia carrier expecting an affected infant is vaginal delivery.

    PubMed

    Ljung, R

    2010-05-01

    The optimal mode of delivery of a haemophilia carrier expecting a child is still a matter of uncertainty and debate. The aim of this commentary/review is to suggest that normal vaginal delivery should be the recommended mode of delivery for the majority of carriers, based on review of studies on obstetric aspects of haemophilia. About 2.0-4.0% of all haemophilia boys born in countries with a good standard of health care will suffer from ICH during the neonatal period. This is an average figure including all modes of delivery and regardless of whether the carrier status of the mother or the haemophilia status of the foetus was known or not at the time of delivery. On the basis of current literature, one may conclude that the risk of serious bleeding in the neonate affected with haemophilia is small in conjunction with normal vaginal delivery. It should be possible to further reduce the low frequency of complications if appropriate precautions are taken when planning the delivery in pregnant woman with known carrier status, if the sex of the foetus is known and, even more, when the haemophilia status of the foetus is known. Instrumental delivery such as use of vacuum extraction and foetal scalp monitors must be avoided at delivery of carriers.

  15. A summary of porous tube plant nutrient delivery system investigations from 1985 to 1991

    NASA Technical Reports Server (NTRS)

    Dreschel, T. W.; Brown, C. S.; Piastuch, W. C.; Hinkle, C. R.; Sager, J. C.; Wheeler, R. M.; Knott, W. M.

    1992-01-01

    The Controlled Ecological Life Support System (CELSS) Program is a research effort to evaluate biological processes at a one person scale to provide air, water, and food for humans in closed environments for space habitation. This program focuses currently on the use of conventional crop plants and the use of hydroponic systems to grow them. Because conventional hydroponic systems are dependent on gravity to conduct solution flow, they cannot be used in the microgravity of space. Thus, there is a need for a system that will deliver water and nutrients to plant roots under microgravity conditions. The Plant Space Biology Program is interested in investigating the effect that the space environment has on the growth and development of plants. Thus, there is also a need to have a standard nutrient delivery method for growing plants in space for research into plant responses to microgravity. The Porous Tube Plant Nutrient Delivery System (PTPNDS) utilizes a hydrophilic, microporous material to control water and nutrient delivery to plant roots. It has been designed and analyzed to support plant growth independent of gravity and plans are progressing to test it in microgravity. It has been used successfully to grow food crops to maturity in an earth-bound laboratory. This document includes a bibliography and summary reports from the growth trials performed utilizing the PTPNDS.

  16. Maternal nutrient restriction affects properties of skeletal muscle in offspring

    PubMed Central

    Zhu, Mei J; Ford, Stephen P; Means, Warrie J; Hess, Bret W; Nathanielsz, Peter W; Du, Min

    2006-01-01

    Maternal nutrient restriction (NR) affects fetal development with long-term consequences on postnatal health of offspring, including predisposition to obesity and diabetes. Most studies have been conducted in fetuses in late gestation, and little information is available on the persistent impact of NR from early to mid-gestation on properties of offspring skeletal muscle, which was the aim of this study. Pregnant ewes were subjected to 50% NR from day 28–78 of gestation and allowed to deliver. The longissimus dorsi muscle was sampled from 8-month-old offspring. Maternal NR during early to mid-gestation decreased the number of myofibres in the offspring and increased the ratio of myosin IIb to other isoforms by 17.6 ± 4.9% (P < 0.05) compared with offspring of ad libitum fed ewes. Activity of carnitine palmitoyltransferase-1, a key enzyme controlling fatty acid oxidation, was reduced by 24.7 ± 4.5% (P < 0.05) in skeletal muscle of offspring of NR ewes and would contribute to increased fat accumulation observed in offspring of NR ewes. Intramuscular triglyceride content (IMTG) was increased in skeletal muscle of NR lambs, a finding which may be linked to predisposition to diabetes in offspring of NR mothers, since enhanced IMTG predisposes to insulin resistance in skeletal muscle. Proteomic analysis by two-dimensional gel electrophoresis demonstrated downregulation of several catabolic enzymes in 8-month-old offspring of NR ewes. These data demonstrate that the early to mid-gestation period is important for skeletal muscle development. Impaired muscle development during this stage of gestation affects the number and composition of fibres in offspring which may lead to long-term physiological consequences, including predisposition to obesity and diabetes. PMID:16763001

  17. Nutrient Exchange through Hyphae in Intercropping Systems Affects Yields

    ERIC Educational Resources Information Center

    Thun, Tim Von

    2013-01-01

    Arbuscular mycorrhizae fungi (AMF) play a large role in the current understanding of the soil ecosystem. They increase nutrient and water uptake, improve soil structure, and form complex hyphal networks that transfer nutrients between plants within an ecosystem. Factors such as species present, the physiological balance between the plants in the…

  18. High-frequency nutrient monitoring to infer seasonal patterns in catchment source availability, mobilisation and delivery.

    PubMed

    Bende-Michl, Ulrike; Verburg, Kirsten; Cresswell, Hamish P

    2013-11-01

    To explore the value of high-frequency monitoring to characterise and explain riverine nutrient concentration dynamics, total phosphorus (TP), reactive phosphorus (RP), ammonium (NH4-N) and nitrate (NO3-N) concentrations were measured hourly over a 2-year period in the Duck River, in north-western Tasmania, Australia, draining a 369-km(2) mixed land use catchment area. River discharge was observed at the same location and frequency, spanning a wide range of hydrological conditions. Nutrient concentrations changed rapidly and were higher than previously observed. Maximum nutrient concentrations were 2,577 μg L(-1) TP, 1,572 μg L(-1) RP, 972 μg L(-1) NH₄-N and 1,983 μg L(-1) NO₃-N, respectively. Different nutrient response patterns were evident at seasonal, individual event and diurnal time scales-patterns that had gone largely undetected in previous less frequent water quality sampling. Interpretation of these patterns in terms of nutrient source availability, mobilisation and delivery to the stream allowed the development of a conceptual model of catchment nutrient dynamics. Functional stages of nutrient release were identified for the Duck River catchment and were supported by a cluster analysis which confirmed the similarities and differences in nutrient responses caused by the sequence of hydrologic events: (1) a build-up of nutrients during periods with low hydrologic activity, (2) flushing of readily available nutrient sources at the onset of the high flow period, followed by (3) a switch from transport to supply limitation, (4) the accessibility of new nutrient sources with increasing catchment wetness and hydrologic connectivity and (5) high nutrient spikes occurring when new sources become available that are easily mobilised with quickly re-established hydrologic connectivity. Diurnal variations that could be influenced by riverine processes and/or localised point sources were also identified as part of stage (1) and during late recession of some of

  19. Nutrient enrichment affects the mechanical resistance of aquatic plants

    PubMed Central

    Puijalon, Sara

    2012-01-01

    For many plant species, nutrient availability induces important anatomical responses, particularly the production of low-density tissues to the detriment of supporting tissues. Due to the contrasting biomechanical properties of plant tissues, these anatomical responses may induce important modifications in the biomechanical properties of plant organs. The aim of this study was to determine the effects of nutrient enrichment on the anatomical traits of two freshwater plant species and its consequences on plant biomechanical performance. Two plant species were grown under controlled conditions in low versus high nutrient levels. The anatomical and biomechanical traits of the plant stems were measured. Both species produced tissues with lower densities under nutrient-rich conditions, accompanied by modifications in the structure of the aerenchyma for one species. As expected, nutrient enrichment also led to important modifications in the biomechanical properties of the stem for both species. In particular, mechanical resistance (breaking force and strength) and stiffness of stems were significantly reduced under nutrient rich conditions. The production of weaker stem tissues as a result of nutrient enrichment may increase the risk of plants to mechanical failure, thus challenging plant maintenance in mechanically stressful or disturbed habitats. PMID:23028018

  20. Nutrient omission in Bt cotton affects soil organic carbon and nutrients status

    NASA Astrophysics Data System (ADS)

    Aladakatti, Y. R.; Biradar, D. P.; Satyanarayana, T.; Majumdar, K.; Shivamurthy, D.

    2012-04-01

    Studies carried out at the University of Agricultural Sciences, Dharwad, India, in medium black soils assessed the effect of nutrient omission in Bt cotton and its effect on the soil organic carbon (SOC) and available nutrients at the end of second consecutive year of nutrient omission. The study also assessed the extent of contribution of the macro and micronutrients towards seed cotton yield. The experiment consisting 11 treatments omitting a nutrient in each treatment including an absolute control without any nutrients was conducted in a Randomised Block Design with three replications. Cotton crop sufficiently fertilized with macro and micro nutrients (165 : 75 : 120 NPK kg ha-1 and 20 kg each of CaSO4, and MgSO4, 10 kg of S, 20 kg each of ZnSO4, FeSO4 and 0.1 per cent Boron twice as foliar spray) was taken as a standard check to assess the contribution of each nutrient in various nutrient omission treatments. Soils of each treatment were analysed initially and after each crop of cotton for SOC and available nutrient status. Results indicated that the SOC decreased after each crop of cotton in absolute control where no nutrients were applied (0.50 % to 0.38 %) and also in the N omission treatment (0.50 % to 0.35 %). But there was no significant impact of omission of P, K and other nutrients on soil organic carbon. Soil available N, P and K in the soil were reduced as compared to the initial soil status after first and second crop of cotton in the respective treatment where these nutrients were omitted. The soil available N, P and K were reduced to the extent of 61 kg ha-1, 7.1 kg ha-1 and 161.9 kg ha-1 in the respective nutrient omission treatment at end of second crop of cotton as compared to the initial status of these nutrients in the soil. This might be due to the mining of these nutrients from the soil nutrient pool with out addition of these nutrients extraneously. The nutrient status of N, P and K remained almost similar in omission of other nutrients

  1. Food microstructure affects the bioavailability of several nutrients.

    PubMed

    Parada, J; Aguilera, J M

    2007-03-01

    There is an increased interest in the role that some nutrients may play in preventing or ameliorating the effect of major diseases (for example, some types of cancer, cardiovascular diseases, eye disorders, among others). In this respect, the bioavailability or the proportion of an ingested nutrient that is made available (that is, delivered to the bloodstream) for its intended mode of action is more relevant than the total amount present in the original food. Disruption of the natural matrix or the microstructure created during processing may influence the release, transformation, and subsequent absorption of some nutrients in the digestive tract. Alternatively, extracts of bioactive molecules (for example, nutraceuticals) and beneficial microorganisms may be protected during their transit in the digestive system to the absorption sites by encapsulation in designed matrices. This review summarizes relevant in vivo and in vitro methods used to assess the bioavailability of some nutrients (mostly phytochemicals), types of microstructural changes imparted by processing and during food ingestion that are relevant in matrix-nutrient interactions, and their effect on the bioavailability of selected nutrients.

  2. Climate Change Will Affect Nutrient Dispersal In UK Estuaries

    NASA Astrophysics Data System (ADS)

    Bergamaschi, B. A.; Robins, P. E.; Cooper, D.

    2015-12-01

    It is still largely unclear how nutrients that travel through the catchment-river system are distributed within estuaries. How long will nutrients remain in the estuary, and what proportion will disperse offshore into the oceans? In the UK, where many catchments are relatively small and steep, estuaries react rapidly to rainfall events, which crucially control the mixing process, even though tidal stirring is generally large. Seasonal and short-term variability in estuarine functioning is therefore greater than variabilities over semi-diurnal timescales linked to tidal cycling. We present both published and on-going research that is emerging from an interdisciplinary pan-UK NERC Macronutrient Cycles Programme (macronutrient-cycles.ouce.ox.ac.uk). We pull together intensive field campaigns (Howlett et al. 2015) and model simulations (Robins et al. 2015), and present for the first time coupled simulations of catchment-river-estuary nutrient transport, using a variety of hydrological and hydrodynamic models. We investigate the response of the hydrodynamics and nutrients to extreme flows and storm surge events, and the response to climate change by simulating the IPCC 5th Assessment projections for 2100. On-going research will extend this integrated approach into the macronutrient controls on atmospheric-land exchange. Emerging research from our UK case study suggests that simulating the hourly river hydrograph, rather than daily-averaged, is important for estuarine response and recovery; daily-averaged flowrates, which are commonly used, under-predict the offshore transport of nutrients. Moreover, biogeochemical processing, whilst detected over estuarine residence times, did not measurably alter the estuarine concentrations, due to the much stronger advective fluxes. By simulating past mean and extreme events, using time-series analysis of river flow and tidal level data collected over the past 50 years, we are able to characterise the future estuarine nutrient

  3. A nutrient combination that can affect synapse formation.

    PubMed

    Wurtman, Richard J

    2014-04-23

    Brain neurons form synapses throughout the life span. This process is initiated by neuronal depolarization, however the numbers of synapses thus formed depend on brain levels of three key nutrients-uridine, the omega-3 fatty acid DHA, and choline. Given together, these nutrients accelerate formation of synaptic membrane, the major component of synapses. In infants, when synaptogenesis is maximal, relatively large amounts of all three nutrients are provided in bioavailable forms (e.g., uridine in the UMP of mothers' milk and infant formulas). However, in adults the uridine in foods, mostly present at RNA, is not bioavailable, and no food has ever been compelling demonstrated to elevate plasma uridine levels. Moreover, the quantities of DHA and choline in regular foods can be insufficient for raising their blood levels enough to promote optimal synaptogenesis. In Alzheimer's disease (AD) the need for extra quantities of the three nutrients is enhanced, both because their basal plasma levels may be subnormal (reflecting impaired hepatic synthesis), and because especially high brain levels are needed for correcting the disease-related deficiencies in synaptic membrane and synapses.

  4. Basin-Scale Exports vs. Coastal Delivery of Carbon, Nutrients and Particulates Above and Below Arctic River Deltas

    NASA Astrophysics Data System (ADS)

    Striegl, R. G.; Tank, S. E.; Weeks, G.; Holmes, R. M.; McClelland, J. W.

    2014-12-01

    Recent studies have substantially improved our understanding of water, sediment and materials exports by arctic rivers. Seasonality of exports, particularly during the spring freshet, is better quantified, as are the inland sources of water and sediment discharge and the source and chemical character of other material exports, including carbon and nutrients. Measurements on small rivers discharging directly to the Arctic Ocean and lacking complex deltas can accurately quantify local inputs to coastal regions. However, the majority of hydrologic inputs to the Arctic Ocean derive from 6 major Eurasian and North American rivers. Water, sediment, and chemical exports from these rivers are typically measured above head of tide, far inland, and commonly above large river deltas. These deltas settle particles and provide favorable environments for deposition, storage, and biogeochemical consumption, production, and transformation of aquatic carbon and nutrients. Consequently, basin exports measured above river deltas likely misrepresent actual delivery to coastal regions. In addition to accumulating sediment, observed and modeled arctic delta effects include enrichment of the organic content of suspended solids, increased dissolved organic carbon and nitrogen (DOC; DON) concentration, decreased inorganic nutrient concentration, and settling and likely increased bioavailability of particle associated contaminants, such as mercury. Increased DOC concentration in the Mackenzie River delta has also been associated with a change in DOC quality, with increased potential for biodegradation of DOC and decreased potential for photodegradation of DOC from head of tide to within the delta. For the most part, assessments of differences between head of tide basin exports and coastal delivery tend to be qualitative rather than quantitative, largely because of difficulties quantifying tidally affected flow. This points to the need to resolve data gaps, improve quantitative assessments

  5. Maternal inflammation at delivery affects assessment of maternal iron status.

    PubMed

    Lee, Sunmin; Guillet, Ronnie; Cooper, Elizabeth M; Westerman, Mark; Orlando, Mark; Pressman, Eva; O'Brien, Kimberly O

    2014-10-01

    Pregnant adolescents (aged ≤ 18 y, n = 253) were followed from ≥ 12 wk of gestation to delivery to assess longitudinal changes in anemia and iron status and to explore associations between iron status indicators, hepcidin, and inflammatory markers. Hemoglobin, soluble transferrin receptor (sTfR), ferritin, serum iron, erythropoietin (EPO), hepcidin, C-reactive protein, interleukin-6 (IL-6), folate, and vitamin B-12 were measured, and total body iron (TBI) (milligrams per kilogram) was calculated using sTfR and ferritin values. Anemia prevalence increased from trimesters 1 and 2 (3-5%, <28 wk) to trimester 3 (25%, 33.2 ± 3.7 wk, P < 0.0001). The prevalence of iron deficiency (sTfR > 8.5 mg/L) doubled from pregnancy to delivery (7% to 14%, P = 0.04). Ferritin and hepcidin concentrations at delivery may have been elevated as a consequence of inflammation because IL-6 concentrations at delivery were 1.6-fold higher than those obtained at 26.1 ± 3.3 wk of gestation (P < 0.0001), and a positive association was found between IL-6 and both hepcidin and ferritin at delivery (P < 0.01). EPO was consistently correlated with hemoglobin (r = -0.36 and -0.43, P < 0.001), ferritin (r = -0.37 and -0.32, P < 0.0001), sTfR (r = 0.35 and 0.25, P < 0.001), TBI (r = -0.44 and -0.37, P < 0.0001), and serum iron (r = -0.22 and -0.16, P < 0.05) at mid-gestation and at delivery, respectively. EPO alone explained the largest proportion of variance in hemoglobin at 26.0 ± 3.3 wk of gestation (R(2) = 0.13, P = 0.0001, n = 113) and at delivery (R(2) = 0.19, P < 0.0001, n = 192). Pregnant adolescents are at high risk of anemia. EPO is a sensitive indicator of iron status across gestation, is not affected by systemic inflammation, and may better predict risk of anemia at term. The trial was registered at clinicaltrials.gov as NCT01019902.

  6. Recent Advances in Modeling Phosphorus and Nitrogen Delivery to the Gulf of Mexico and Implications for Managing Nutrients n the Mississippi River Basin

    NASA Astrophysics Data System (ADS)

    Alexander, R. B.; Smith, R. A.; Schwarz, G. E.; Boyer, E. W.; Nolan, J. V.; Brakebill, J. W.

    2008-12-01

    Although the increased availability of reactive nutrients in past decades has benefited society via food and energy production, the corresponding rise in nutrient loadings to aquatic ecosystems is of particular concern, especially in many estuaries globally where increased nutrient loads have contributed to eutrophic conditions. In the United States, elevated riverine nutrients have contributed to stressed trophic conditions in a majority of estuaries, including the shallow coastal waters of the Louisiana shelf in the northern Gulf of Mexico, where both nitrogen and phosphorus loadings are recognized as contributing to seasonal hypoxic conditions. Advances in geospatial modeling of nitrogen and phosphorus sources and transport in the Mississippi and Atchafalaya River Basins (MARB), as reported in a recent U.S. Geological Survey (USGS) study, provide important information to support improved assessments and management of nutrient loadings to the northern Gulf of Mexico. We summarize the findings of this study and discuss the implications for managing nutrient sources in the MARB. The study reveals important differences in the sources and aquatic transport of nitrogen and phosphorus that affect delivery to the Gulf. Although agricultural sources contribute a majority of the delivered nutrients to the Gulf, corn and soybean cultivation is the largest contributor of nitrogen whereas phosphorus originates primarily from animal manure on pasture and rangelands. Atmospheric deposition is the second leading source of nitrogen, with urban sources contributing relatively small quantities of both nutrients. Furthermore, we find that both nitrogen and phosphorus delivery to the Gulf is controlled by hydrological and biogeochemical processes (e.g., water travel time, denitrification, storage) that scale with stream size, although phosphorus also displays large local- and regional-scale differences in delivery caused by reservoir trapping. The importance of these processes

  7. Interacting Physical and Biological Processes Affecting Nutrient Transport Through Human Dominated Landscapes

    NASA Astrophysics Data System (ADS)

    Finlay, J. C.

    2015-12-01

    Human activities increasingly dominate biogeochemical cycles of limiting nutrients on Earth. Urban and agricultural landscapes represent the largest sources of excess nutrients that drive water quality degradation. The physical structure of both urban and agricultural watersheds has been extensively modified, and these changes have large impacts on water and nutrient transport. Despite strong physical controls over nutrient transport in human dominated landscapes, biological processes play important roles in determining the fates of both nitrogen and phosphorus. This talk uses examples from research in urban and agricultural watersheds in the Midwestern USA to illustrate interactions of physical and biological controls over nutrient cycles that have shifted nitrogen (N) and phosphorus (P) sources and cycling in unexpected ways in response to management changes. In urban watersheds, efforts to improve water quality have been hindered by legacy sources of phosphorus added to storm water through transport to drainage systems by vegetation. Similarly, reductions in field erosion in agricultural watersheds have not led to major reductions in phosphorus transport, because of continued release of biological sources of P. Where management of phosphorus has been most effective in reducing eutrophication of lakes, decreases in N removal processes have led to long term increases in N concentration and transport. Together, these examples show important roles for biological processes affecting nutrient movement in highly modified landscapes. Consideration of the downstream physical and biological responses of management changes are thus critical toward identification of actions that will most effectively reduce excess nutrients watersheds and coastal zones.

  8. Elevated tropospheric ozone affects the concentration and allocation of mineral nutrients of two bamboo species.

    PubMed

    Zhuang, Minghao; Lam, Shu Kee; Li, Yingchun; Chen, Shuanglin

    2017-01-15

    The increase in tropospheric ozone (O3) affects plant physiology and ecosystem processes, and consequently the cycle of nutrients. While mineral nutrients are critical for plant growth, the effect of elevated tropospheric O3 concentration on the uptake and allocation of mineral nutrients by plants is not well understood. Using open top chambers (OTCs), we investigated the effect of elevated O3 on calcium (Ca), magnesium (Mg) and iron (Fe) in mature bamboo species Phyllostachys edulis and Oligostachyum lubricum. Our results showed that elevated O3 decreased the leaf biomass of P. edulis and O. lubricum by 35.1% and 26.7%, respectively, but had no significant effect on the biomass of branches, stem or root. For P. edulis, elevated O3 increased the nutrient (Ca, Mg and Fe) concentration and allocation in leaf but reduced the concentration in other organs. In contrast, elevated O3 increased the nutrient concentration and allocation in the branch of O. lubricum but decreased that of other organs. We also found that that P. edulis and O. lubricum responded differently to elevated O3 in terms of nutrient (Ca, Mg and Fe) uptake and allocation. This information is critical for nutrient management and adaptation strategies for sustainable growth of P. edulis and O. lubricum under global climate change.

  9. Synchrotron-based and globar-sourced molecular (micro)spectroscopy contributions to advances in new hulless barley (with structure alteration) research on molecular structure, molecular nutrition, and nutrient delivery.

    PubMed

    Yang, Ling; Yu, Peiqiang

    2017-01-02

    This paper aimed to review synchrotron-based and globar-sourced molecular infrared (micro)spectroscopy contributions to advances in new hulless barley (with structure alteration) research on molecular structure, molecular nutrition, and nutrient delivery in ruminants. It reviewed recent progress in barley varieties, its utilization for animal and human, inherent structure features and chemical make-up, evaluation and research methodology, breeding progress, rumen degradation, and intestinal digestion. The emphasis of this review was focused on the effect of alteration of carbohydrate traits of newly developed hulless barley on molecular structure changes and nutrient delivery and quantification of the relationship between molecular structure features and changes and truly absorbed nutrient supply to ruminants. This review provides an insight into how inherent structure changes on a molecular basis affect nutrient utilization and availability in ruminants.

  10. Factors affecting nutrient trends in major rivers of the Chesapeake Bay Watershed

    USGS Publications Warehouse

    Sprague, Lori A.; Langland, M.J.; Yochum, S.E.; Edwards, R.E.; Blomquist, J.D.; Phillips, S.W.; Shenk, G.W.; Preston, S.D.

    2000-01-01

    Trends in nutrient loads and flow-adjusted concentrations in the major rivers entering Chesapeake Bay were computed on the basis of water-quality data collected between 1985 and 1998 at 29 monitoring stations in the Susquehanna, Potomac, James, Rappahannock, York, Patuxent, and Choptank River Basins. Two computer models?the Chesapeake Bay Watershed Model (WSM) and the U.S. Geological Survey?s 'Spatially Referenced Regressions on Watershed attributes' (SPARROW) Model?were used to help explain the major factors affecting the trends. Results from WSM simulations provided information on temporal changes in contributions from major nutrient sources, and results from SPARROW model simulations provided spatial detail on the distribution of nutrient yields in these basins. Additional data on nutrient sources, basin characteristics, implementation of management practices, and ground-water inputs to surface water were analyzed to help explain the trends. The major factors affecting the trends were changes in nutrient sources and natural variations in streamflow. The dominant source of nitrogen and phosphorus from 1985 to 1998 in six of the seven tributary basins to Chesapeake Bay was determined to be agriculture. Because of the predominance of agricultural inputs, changes in agricultural nutrient sources such as manure and fertilizer, combined with decreases in agricultural acreage and implementation of best management practices (BMPs), had the greatest impact on the trends in flow-adjusted nutrient concentrations. Urban acreage and population, however, were noted to be increasing throughout the Chesapeake Bay Watershed, and as a result, delivered loads of nutrients from urban areas increased during the study period. Overall, agricultural nutrient management, in combination with load decreases from point sources due to facility upgrades and the phosphate detergent ban, led to downward trends in flow-adjusted nutrient concentrations atmany of the monitoring stations in the

  11. Solubility and Plant Availability of Nutrients as Affected by Soil Drainage Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn growth is affected due to oxygen deficiency and root death in a perched water table (PWT). The study objective was to evaluate a surface application of FGD gypsum (FGDG) and glyphosate (GLY) on nutrient uptake in corn with different drainage conditions. The experiment was conducted in greenhous...

  12. Source and delivery of nutrients to receiving waters in the Northeastern and Mid-Atlantic regions of the United States

    USGS Publications Warehouse

    Moore, Richard B.; Johnston, Criag M.; Smith, Richard A.; Milstead, Bryan

    2011-01-01

    This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake.

  13. Source and Delivery of Nutrients to Receiving Waters in the Northeastern and Mid-Atlantic Regions of the United States

    USGS Publications Warehouse

    Moore, R.B.; Johnston, C.M.; Smith, R.A.; Milstead, B.

    2011-01-01

    This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  14. Assessment of changes in nutrient and sediment delivery to and carbon accumulation in coastal oceans of the Eastern United States

    NASA Astrophysics Data System (ADS)

    Bergamaschi, B. A.; Smith, R. A.; Shih, J. S.; Sohl, T. L.; Sleeter, B. M.; Zhu, Z.

    2014-12-01

    Land-use and land-cover distributions are primary determinants of terrestrial fluxes of sediments and nutrients to coastal oceans. Sediment and nutrient delivery to coastal waters have already been significantly altered by changes in population and land use, resulting in modified patterns of coastal production and carbon storage. Continued population growth and increasing agricultural areal extent and intensity are expected to accelerate these changes. The USGS LandCarbon project developed prospective future land use and land cover projections based on IPCC scenarios A1b, A2 and B1 to 2050 as the basis for a multitude of biogeochemical assessments. We assessed the impacts on delivery of nutrients and sediments to the coastal ocean, and concomitant carbon storage. Fluxes were estimated using the SPARROW model, calibrated on historical water quality measurements. Significantly greater fluxes of nutrients and sediments to coastal waters by 2050 are projected by the model. For example, for the Eastern United States, nitrate fluxes for 2050 are projected to be16 to 52 percent higher than the baseline year, depending on scenario. As a consequence, an associated increase in the frequency and duration of coastal and estuarine hypoxia events and harmful algal blooms could be expected. Model estimates indicate that these prospective future nutrient and sediment fluxes will increase carbon storage rates in coastal waters by 18 to 56 percent in some regions.

  15. Conceptual design of a closed loop nutrient solution delivery system for CELSS implementation in a micro-gravity environment

    NASA Technical Reports Server (NTRS)

    Schwartzkopf, Steven H.; Oleson, Mel W.; Cullingford, Hatice S.

    1990-01-01

    Described here are the results of a study to develop a conceptual design for an experimental closed loop fluid handling system capable of monitoring, controlling, and supplying nutrient solution to higher plants. The Plant Feeder Experiment (PFE) is designed to be flight tested in a microgravity environment. When flown, the PFX will provide information on both the generic problems of microgravity fluid handling and the specific problems associated with the delivery of the nutrient solution in a microgravity environment. The experimental hardware is designed to fit into two middeck lockers on the Space Shuttle, and incorporates several components that have previously been flight tested.

  16. Growth of non-Saccharomyces yeasts affects nutrient availability for Saccharomyces cerevisiae during wine fermentation.

    PubMed

    Medina, Karina; Boido, Eduardo; Dellacassa, Eduardo; Carrau, Francisco

    2012-07-02

    Yeast produces numerous secondary metabolites during fermentation that impact final wine quality. Although it is widely recognized that growth of diverse non-Saccharomyces (NS) yeast can positively affect flavor complexity during Saccharomyces cerevisiae wine fermentation, the inability to control spontaneous or co-fermentation processes by NS yeast has restricted their use in winemaking. We selected two NS yeasts from our Uruguayan native collection to study NS-S. cerevisiae interactions during wine fermentation. The selected strains of Hanseniaspora vineae and Metschnikowia pulcherrima had different yeast assimilable nitrogen consumption profiles and had different effects on S. cerevisiae fermentation and growth kinetics. Studies in which we varied inoculum size and using either simultaneous or sequential inoculation of NS yeast and S. cerevisiae suggested that competition for nutrients had a significant effect on fermentation kinetics. Sluggish fermentations were more pronounced when S. cerevisiae was inoculated 24h after the initial stage of fermentation with a NS strain compared to co-inoculation. Monitoring strain populations using differential WL nutrient agar medium and fermentation kinetics of mixed cultures allowed for a better understanding of strain interactions and nutrient addition effects. Limitation of nutrient availability for S. cerevisiae was shown to result in stuck fermentations as well as to reduce sensory desirability of the resulting wine. Addition of diammonium phosphate (DAP) and a vitamin mix to a defined medium allowed for a comparison of nutrient competition between strains. Addition of DAP and the vitamin mix was most effective in preventing stuck fermentations.

  17. Misreporting of dietary intake affects estimated nutrient intakes in low-income Spanish-speaking women.

    PubMed

    Banna, Jinan C; Fialkowski, Marie K; Townsend, Marilyn S

    2015-07-01

    Misreporting of dietary intake affects the validity of data collected and conclusions drawn in studies exploring diet and health outcomes. One consequence of misreporting is biological implausibility. Little is known regarding how accounting for biological implausibility of reported intake affects nutrient intake estimates in Hispanics, a rapidly growing demographic in the United States. Our study explores the effect of accounting for plausibility on nutrient intake estimates in a sample of Mexican-American women in northern California in 2008. Nutrient intakes are compared with Dietary Reference Intake recommendations, and intakes of Mexican-American women in a national survey are presented as a reference. Eighty-two women provided three 24-hour recalls. Reported energy intakes were classified as biologically plausible or implausible using the reported energy intakes to total energy expenditure cutoff of <0.76 or >1.24, with low-active physical activity levels used to estimate total energy expenditure. Differences in the means of nutrient intakes between implausible (n=36) and plausible (n=46) reporters of energy intake were examined by bivariate linear regression. Estimated energy, protein, cholesterol, dietary fiber, and vitamin E intakes were significantly higher in plausible reporters than implausible. There was a significant difference between the proportions of plausible vs implausible reporters meeting recommendations for several nutrients, with a larger proportion of plausible reporters meeting recommendations. Further research related to misreporting in Hispanic populations is warranted to explore the causes and effects of misreporting in studies measuring dietary intake, as well as actions to be taken to prevent or account for this issue.

  18. A Field Intensive Approach to Understanding Relationships Between Vegetation, Landscape, and Management Factors and Their Effects on Stream Sediment and Nutrient Delivery in the Lake Tahoe Basin

    NASA Astrophysics Data System (ADS)

    Meidav, J. S.; Barbour, M. G.

    2008-12-01

    Understanding how management and vegetation type affect watershed factors is an important issue worldwide and key to connecting upland and downstream resource conservation. This work evaluated the connections between stream sediment and nutrient (nitrogen and phosphorus) constituents with land management and vegetation factors within the highest sediment yield watershed of the Lake Tahoe Basin (CA-NV), Blackwood Creek. Among plant community types, sub-watersheds with the highest amount of riparian/wetland vegetated areas were linked with the highest sediment and nutrient filtering capacity. Riparian/wetland areas appeared to act as a sink for sediment and nutrients during the peak flow period, while being a source area during base flow, corroborating other studies on disturbance effects on the hydrograph. Separating the watershed effects of forest species density and basal area from past management activities (e.g. logging and mining) proved equivocal on a sub-watershed scale. As the magnitude of landscape management impacts increased, the effects of peak flows on sediment and nutrient yield increased. Within more disturbed watersheds, the inorganic fraction of sediment and phosphorus dominated transport, which implicated in- and near-channel sources and features as having disproportionate effects on sub-watershed scale sediment and nutrient delivery. Without employing catchment-wide treatments or a priori linear models, the methods employed discerned that small particle sources, linked to lake clarity loss, are positively connected to the inorganic fraction and riparian, near-channel, sand deposits while manifesting a negative correlation with in-channel clay. Linking channel morphology and riparian and upland vegetation restoration (structure and process) in tandem will be important as efforts continue in the restoration of Lake Tahoe's ecological health.

  19. Potato growth in a porous tube water and nutrient delivery system

    NASA Technical Reports Server (NTRS)

    Bula, R. J.; Morrow, R. C.; Tibbitts, T. W.

    1996-01-01

    Potato (Solanum tuberosum L.) cv. 'Norland', vegetative growth and tuber productivity grown in the porous water and nutrient delivery system (PTNDS) developed by the Wisconsin Center for Space Automation and Robotics were compared with the vegetative growth and tuber productivity of plants grown in a peat:vermiculite potting mixture (PT/VR). The plants were grown at 12, 16, and 24-h light periods, 18 degrees C constant temperature, 70% relative humidity, and 300 micromol m-2 s-1 photosynthetic photon flux. Canopy height of plants grown in the PT/VR system was taller than that of plants grown in the PTNDS system. Canopy height differences were greatest when the plants were grown under a 24-h photoperiod. Leaf and stem dry masses were similar for plants grown in the two systems under the 12-h photoperiod. Under the 24-h photoperiod, leaf and stem dry masses of plants grown in the PT/VR system were more than 3 times those of plants grown in the PTNDS system. Tuber dry masses were similar for plants grown in the two systems under the 12-h photoperiod. Under the 24 h-photoperiod, tuber dry weights of plants grown in the PT/VR system were more than twice those of plants grown in the PTNDS system. A slightly higher harvest index (ratio of tuber weight to leaf plus stem weight) was noted for the plants grown in the PTNDS than for the plants grown in the PT/VR system. Plants grown in the PTNDS system at the 24-h photoperiod matured earlier than plants grown at this photoperiod in the PT/VR system. Vegetative growth and tuber productivity of plants grown under the 16-h photoperiod generally were intermediate to those noted for plants grown under the 12 and 24-h photoperiods. These results indicate that potato plants grown in a PTNDS system may require less plant growing volume, mature in a shorter time, and likely produce more tubers per unit area compared with plants grown in the PT/VR system. These plant characteristics are a distinct advantage for a plant growing unit of

  20. Potato growth in a porous tube water and nutrient delivery system.

    PubMed

    Bula, R J; Morrow, R C; Tibbitts, T W

    1996-01-01

    Potato (Solanum tuberosum L.) cv. 'Norland', vegetative growth and tuber productivity grown in the porous water and nutrient delivery system (PTNDS) developed by the Wisconsin Center for Space Automation and Robotics were compared with the vegetative growth and tuber productivity of plants grown in a peat:vermiculite potting mixture (PT/VR). The plants were grown at 12, 16, and 24-h light periods, 18 degrees C constant temperature, 70% relative humidity, and 300 micromol m-2 s-1 photosynthetic photon flux. Canopy height of plants grown in the PT/VR system was taller than that of plants grown in the PTNDS system. Canopy height differences were greatest when the plants were grown under a 24-h photoperiod. Leaf and stem dry masses were similar for plants grown in the two systems under the 12-h photoperiod. Under the 24-h photoperiod, leaf and stem dry masses of plants grown in the PT/VR system were more than 3 times those of plants grown in the PTNDS system. Tuber dry masses were similar for plants grown in the two systems under the 12-h photoperiod. Under the 24 h-photoperiod, tuber dry weights of plants grown in the PT/VR system were more than twice those of plants grown in the PTNDS system. A slightly higher harvest index (ratio of tuber weight to leaf plus stem weight) was noted for the plants grown in the PTNDS than for the plants grown in the PT/VR system. Plants grown in the PTNDS system at the 24-h photoperiod matured earlier than plants grown at this photoperiod in the PT/VR system. Vegetative growth and tuber productivity of plants grown under the 16-h photoperiod generally were intermediate to those noted for plants grown under the 12 and 24-h photoperiods. These results indicate that potato plants grown in a PTNDS system may require less plant growing volume, mature in a shorter time, and likely produce more tubers per unit area compared with plants grown in the PT/VR system. These plant characteristics are a distinct advantage for a plant growing unit of

  1. Potato growth in a porous tube water and nutrient delivery system

    NASA Astrophysics Data System (ADS)

    Bula, R. J.; Morrow, R. C.; Tibbitts, T. W.

    1996-01-01

    Potato (Solanum tuberosum L.) cv. `Norland', vegetative growth and tuber productivity grown in the porous water and nutrient delivery system (PTNDS) developed by the Wisconsin Center for Space Automation and Robotics were compared with the vegetative growth and tuber productivity of plants grown in a peat:vermiculite potting mixture (PT/VR). The plants were grown at 12, 16, and 24-h light periods, 18 degC constant temperature, 70% relative humidity, and 300 mumol.m^-2.s^-1 photosynthetic photon flux. Canopy height of plants grown in the PT/VR system was taller than that of plants grown in the PTNDS system. Canopy height differences were greatest when the plants were grown under a 24-h photoperiod. Leaf and stem dry masses were similar for plants grown in the two systems under the 12-h photoperiod. Under the 24-h photoperiod, leaf and stem dry masses of plants grown in the PT/VR system were more than 3 times those of plants grown in the PTDNS system. Tuber dry masses were similar for plants grown in the two systems under the 12-h photoperiod. Under the 24 h-photoperiod, tuber dry weights of plants grown in the PT/VR system were more than twice those of plants grown in the PTDNS system. A slightly higher harvest index (ratio of tuber weight to leaf plus stem weight) was noted for the plants grown in the PTNDS than for the plants grown in the PT/VR system. Plants grown in the PTNDS system at the 24-h photoperiod matured earlier than plants grown at this photoperiod in the PT/VR system. Vegetative growth and tuber productivity of plants grown under the 16-h photoperiod generally were intermediate to those noted for plants grown under the 12 and 24-h photoperiods. These results indicate that potato plants grown in a PTNDS system may require less plant growing volume, mature in a shorter time, and likely produce more tubers per unit area compared with plants grown in the PT/VR system. These plant characteristics are a distinct advantage for a plant growing unit of a

  2. Variability in the contents of pork meat nutrients and how it may affect food composition databases.

    PubMed

    Reig, Milagro; Aristoy, M-Concepción; Toldrá, Fidel

    2013-10-01

    Pork meat is generally recognised as a food with relevant nutritional properties because of its content in high biological value proteins, group B vitamins, minerals especially heme iron, trace elements and other bioactive compounds. But pork meat also contributes to the intake of fat, saturated fatty acids, cholesterol, and other substances that, in inappropriate amounts, may result in negative physiologically effects. However, there are relevant factors affecting the content of many of these substances and somehow such variability should be taken into consideration. So, genetics, age and even type of muscle have a relevant influence on the amount of fat and the contents in heme iron. Also the composition in fatty acids of triacylglycerols is very sensitive to the contents of cereals in the feed; for instance, polyunsaturated fatty acids may range from 10% to 22% in pork meat. The content of other nutrients, like vitamins E and A, are also depending on the type of feed. Some bioactive substances like coenzyme Q10, taurine, glutamine, creatine, creatinine, carnosine and anserine show a large dependence on the type of muscle. This manuscript describes the main factors affecting the composition of pork meat nutrients and how these changes may affect the general food composition databases.

  3. Select nutrients, progesterone, and interferon tau affect conceptus metabolism and development.

    PubMed

    Bazer, Fuller W; Kim, Jingyoung; Song, Gwonhwa; Ka, Hakhyun; Tekwe, Carmen D; Wu, Guoyao

    2012-10-01

    Interferon tau (IFNT), a novel multifunctional type I interferon secreted by trophectoderm, is the pregnancy recognition signal in ruminants that also has antiviral, antiproliferative, and immunomodulatory bioactivities. IFNT, with progesterone, affects availability of the metabolic substrate in the uterine lumen by inducing expression of genes for transport of select nutrients into the uterine lumen that activate mammalian target of rapamycin (mTOR) cell signaling responsible for proliferation, migration, and protein synthesis by conceptus trophectoderm. As an immunomodulatory protein, IFNT induces an anti-inflammatory state affecting metabolic events that decrease adiposity and glutamine:fructose-6-phosphate amidotransferase 1 activity, while increasing insulin sensitivity, nitric oxide production by endothelial cells, and brown adipose tissue in rats. This short review focuses on effects of IFNT and progesterone affecting transport of select nutrients into the uterine lumen to stimulate mTOR cell signaling required for conceptus development, as well as effects of IFNT on the immune system and adiposity in rats with respect to its potential therapeutic value in reducing obesity.

  4. Conceptual design of a closed loop nutrient solution delivery system for CELSS implementation in a micro-gravity environment

    NASA Technical Reports Server (NTRS)

    Schwartzkopf, Steven H.; Oleson, Mel W.; Cullingford, Hatice S.

    1989-01-01

    This paper describes the results of a study to develop a conceptual design for an experimental, closed-loop fluid handling system capable of monitoring, controlling, and supplying nutrient solution to higher plants. The Plant Feeder Experiment (PFX) is designed to be flight tested in a micro-gravity (micro-g) environment and was developed under NASA's In-Space Technology Experiments Program (INSTEP). When flown, PFX will provide information on both the generic problems of micro-g fluid handling and the specific problems associated with the delivery of nutrient solution in a micro-g environment. The experimental hardware is designed to fit into two middeck lockers on the Space Shuttle, and incorporates several components that have previously been flight tested.

  5. Examining Dehydration and Hypoxic Stress in Wheat Plants Using a Porous Tube Plant Nutrient Delivery System Developed for Microgravity

    NASA Technical Reports Server (NTRS)

    Dreschel, T. W.; Hall, C. R.; Foster, T. E.; Salganic, M.; Warren, L.; Corbett, M.

    2005-01-01

    The Porous Tube Plant Nutrient Delivery System (PTPNDS) was designed for NASA to grow plants in microgravity of space. The system utilizes a controlled fluid loop to supply nutrients and water to plant roots growing on a ceramic surface moistened by capiflary action. A PTPNDS test bed was developed and utilizing remote sensing systems, spectral analyses procedures, gas-exchange, and fluorescence measurements, we examined differences in plant water status for wheat plants (Triticum aestivum, cv. Perigee) grown in a modified growth chamber during the summers of 2003 and 2004. Some differences in plant performance were detectable in the gas-exchange and fluorescence measurements. For instance, in both years the plants grown with the most available water had the lowest rates of photosynthesis and exhibited higher proportions of non-photochemical quenching particularly under low light levels. In addition, small differences in mean leaf water content between treatments were detected using spectral reflectance analyses.

  6. Retro-1 Analogues Differentially Affect Oligonucleotide Delivery and Toxin Trafficking.

    PubMed

    Yang, Bing; Ming, Xin; Abdelkafi, Hajer; Pons, Valerie; Michau, Aurelien; Gillet, Daniel; Cintrat, Jean-Christophe; Barbier, Julien; Juliano, Rudy

    2016-11-21

    Retro-1 is a small molecule that displays two important biological activities: First, it blocks the actions of certain toxins by altering their intracellular trafficking. Second, it enhances the activity of oligonucleotides by releasing them from entrapment in endosomes. This raises the question of whether the two actions involve the same cellular target. Herein we report the effects of several Retro-1 analogues on both toxins and oligonucleotides. We found analogues that affect toxins but not oligonucleotides and vice-versa, while Retro-1 is the only compound that affects both. This indicates that the molecular target(s) involved in the two processes are distinct.

  7. Nutrient delivery from the Mississippi River to the Gulf of Mexico and effects of cropland conservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive nutrients transported from the Mississippi River Basin have created an ecological disaster - Gulf of Mexico hypoxia. Also, in recent years, federal expenditures on agricultural conservation practices have received intense scrutiny. Partly driven by these factors, the USDA Conservation Ef...

  8. Elucidating Sources and Factors Affecting Delivery of Nitrogen to Surface Waters of New York State

    NASA Astrophysics Data System (ADS)

    Golden, H. E.; Boyer, E. W.; Burns, D. A.; Elliott, E.; Kendall, C.; Butler, T.

    2005-12-01

    Rapid changes in power generation, transportation, and agriculture have appreciably altered nitrogen (N) cycling at regional scales, increasing N inputs to landscapes and surface waters. Numerous studies have linked this surplus N to a host of concerns, including eutrophication and violations in drinking water standards. Inputs of N nation-wide have increased during recent decades, primarily from the production and use of fertilizers, the planting of N-fixing crops, and the combustion of fossil fuels. The role of atmospheric N sources is of particular concern in New York, as rates of atmospheric N deposition in the northeast are among the highest in the nation. Our work aims to quantify nitrogen sources and fate in watersheds throughout the state. Further, we intend to elucidate factors controlling the retention and release of N to surface waters. We quantify nitrogen inputs through both measurement data (e.g., from wet and dry atmospheric deposition, precipitation, streamflow, water quality, and isotopic tracers) and from synoptic spatial databases (e.g., of terrain, land use, and fertilizer inputs). We present preliminary results from large catchments in contrasting spatial settings across the state (different land use configurations and atmospheric deposition gradients), illustrating the contribution of nitrogen sources to each region and factors affecting delivery to surface waters. Further, we present 30 years of temporal data from a large watershed (Fall Creek) in the Finger Lakes region of the state to demonstrate how hydrological and biogeochemical factors, over seasons and under varying hydrological regimes, combine to control N dynamics in surface waters. Our collective work provides information that is necessary to develop sound strategies for understanding and managing nutrients at regional scales.

  9. Hydro-climatological non-stationarity shifts patterns of nutrient delivery to an estuarine system

    NASA Astrophysics Data System (ADS)

    Ruibal-Conti, A. L.; Summers, R.; Weaver, D.; Hipsey, M. R.

    2013-08-01

    The influence of hydro-climatological variability on catchment nutrient export was assessed by a retrospective analysis of rainfall, discharge, and total and dissolved nutrient loads for three sub-basins (Serpentine, Murray and Harvey) of the Peel-Harvey catchment, Western Australia. Both, temporal trends and their variability for different hydrological conditions (dry, normal or wet years) were analyzed from 1984 to 2011. Rainfall declined below median values for the study period over the last two decades and runoff decreased significantly in two of the three main rivers. Since Nitrogen (N) and Phosphorus (P) loads were strongly correlated with river discharge, nutrient exports decreased. However, when nutrient loads were flow-adjusted, increases in Total P (TP) and Total N (TN) were observed in the Serpentine and Murray rivers respectively, suggesting new sources of TP and TN and that the flow-export relationship is non-stationary. Dissolved Inorganic Phosphorus (DIP), showed a decreasing tendency in the last decade; but the trend in DIN loads is not clear and it appears to show a decreasing trend until 2004 and an increasing trend from 2004, accompanied with large inter-annual variability. The analysis of TP, TN, DIP and DIN in relation to dry and wet years, indicated that there is a significantly higher load in wet years for all three rivers, except for DIP in the Murray sub-catchment, explained by a higher proportion of soils with a higher Phosphorus Retention Index (PRI). Hydrological conditions, specific sub-catchment characteristics (e.g. soil type) and chemical properties of the nutrients altered the degree of nutrient partitioning (defined as dissolved inorganic to total nutrient concentration). For example, DIP increased to more than 50% of TP in wet years in Harvey and Serpentine but not in the Murray sub-catchment due to a higher PRI, while DIN behaved more randomly and did not show a link to discharge or the catchment soil type. We also found a mild

  10. Do metallic ports in tissue expanders affect postmastectomy radiation delivery?

    SciTech Connect

    Damast, Shari; Beal, Kathryn . E-mail: bealk@mskcc.org; Ballangrud, Ase; Losasso, Thomas J.; Cordeiro, Peter G.; Disa, Joseph J.; Hong, Linda; McCormick, Beryl L.

    2006-09-01

    Purpose: Postmastectomy radiation therapy (PMRT) is often delivered to patients with permanent breast implants. On occasion, patients are irradiated with a tissue expander (TE) in place before their permanent implant exchange. Because of concern of potential under-dosing in these patients, we examined the dosimetric effects of the Magna-Site (Santa Barbara, CA) metallic port that is present in certain TEs. Methods and Materials: We performed ex vivo film dosimetry with single 6-MV and 15-MV photon beams on a water phantom containing a Magna-Site disc in two orientations. Additionally, using in vivo films, we measured the exit dose from 1 patient's TE-reconstructed breast during chest wall treatment with 15-MV tangent beams. Finally, we placed thermoluminescent dosimeters (TLDs) on 6 patients with TEs who received PMRT delivered with 15-MV tangent beams. Results: Phantom film dosimetry revealed decreased transmission in the region of the Magna-Site, particularly with the magnet in the parallel orientation (at 22 mm: 78% transmission with 6 MV, 84% transmission with 15 MV). The transmission measured by in vivo films during single beam treatment concurred with ex vivo results. TLD data showed acceptable variation in median dose to the skin (86-101% prescription dose). Conclusion: Because of potential dosimetric effects of the Magna-Site, it is preferable to treat PMRT patients with permanent implants. However, it is not unreasonable to treat with a TE because the volume of tissue affected by attenuation from the Magna-Site is small. In this scenario, we recommend using 15 MV photons with compensating bolus.

  11. Factors affecting stream nutrient loads: A synthesis of regional SPARROW model results for the continental United States

    USGS Publications Warehouse

    Preston, Stephen D.; Alexander, Richard B.; Schwarz, Gregory E.; Crawford, Charles G.

    2011-01-01

    We compared the results of 12 recently calibrated regional SPARROW (SPAtially Referenced Regressions On Watershed attributes) models covering most of the continental United States to evaluate the consistency and regional differences in factors affecting stream nutrient loads. The models - 6 for total nitrogen and 6 for total phosphorus - all provide similar levels of prediction accuracy, but those for major river basins in the eastern half of the country were somewhat more accurate. The models simulate long-term mean annual stream nutrient loads as a function of a wide range of known sources and climatic (precipitation, temperature), landscape (e.g., soils, geology), and aquatic factors affecting nutrient fate and transport. The results confirm the dominant effects of urban and agricultural sources on stream nutrient loads nationally and regionally, but reveal considerable spatial variability in the specific types of sources that control water quality. These include regional differences in the relative importance of different types of urban (municipal and industrial point vs. diffuse urban runoff) and agriculture (crop cultivation vs. animal waste) sources, as well as the effects of atmospheric deposition, mining, and background (e.g., soil phosphorus) sources on stream nutrients. Overall, we found that the SPARROW model results provide a consistent set of information for identifying the major sources and environmental factors affecting nutrient fate and transport in United States watersheds at regional and subregional scales. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  12. On-The-Move Nutrient Delivery System (NDS): User Acceptability of Rotary Flow Control Version

    DTIC Science & Technology

    2009-04-01

    Baker-Fulco CJ. Overview of dietary intakes during military exercises. In: Not Eating Enough, edited by Marriot SM. Washington, DC: National Academy...Fat Cholesterol Sodium 440mg Potassium Total Carbohydrate Dietary Fiber Sugars Protein Vitamin A Vitamin C Calcium lron Phosphorus 260 o Og Og Omg 18...to fucilitatc fluid and on-the-move nutrient intake . Soldier feedback (n"ඛ) was captured regarding acceplability of NDS fonn and function, and their

  13. Nutrient Deprivation Affects Salmonella Invasion and Its Interaction with the Gastrointestinal Microbiota

    PubMed Central

    Yurist-Doutsch, Sophie; Arrieta, Marie-Claire; Tupin, Audrey; Valdez, Yanet; Antunes, L. Caetano M.; Yen, Ryan; Finlay, B. Brett

    2016-01-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is a foodborne enteric pathogen and a major cause of gastroenteritis in humans. It is known that molecules derived from the human fecal microbiota downregulate S. Typhimurium virulence gene expression and induce a starvation-like response. In this study, S. Typhimurium was cultured in minimal media to mimic starvation conditions such as that experienced by S. Typhimurium in the human intestinal tract, and the pathogen’s virulence in vitro and in vivo was measured. S. Typhimurium cultured in minimal media displayed a reduced ability to invade human epithelial cells in a manner that was at least partially independent of the Salmonella Pathogenicity Island 1 (SPI-1) type III secretion system. Nutrient deprivation did not, however, alter the ability of S. Typhimurium to replicate and survive inside epithelial cells. In a murine model of S. Typhimurium-induced gastroenteritis, prior cultivation in minimal media did not alter the pathogen’s ability to colonize mice, nor did it affect levels of gastrointestinal inflammation. Upon examining the post-infection fecal gastrointestinal microbiota, we found that specifically in the 129Sv/ImJ murine strain S. Typhimurium cultured in minimal media induced differential microbiota compositional shifts compared to that of S. Typhimurium cultured in rich media. Together these findings demonstrate that S. Typhimurium remains a potent pathogen even in the face of nutritional deprivation, but nevertheless that nutrient deprivation encountered in this environment elicits significant changes in the bacterium genetic programme, as well as its capacity to alter host microbiota composition. PMID:27437699

  14. The filter feeder Dreissena polymorpha affects nutrient, silicon, and metal(loid) mobilization from freshwater sediments.

    PubMed

    Schaller, Jörg; Planer-Friedrich, Britta

    2017-05-01

    Organic sediments in aquatic ecosystems are well known sinks for nutrients, silicon, and metal(loid)s. Organic matter-consuming organisms like invertebrate shredders, grazers, and bioturbators significantly affect element fixation or remobilization by changing redox conditions or binding properties of organic sediments. Little is known about the effect of filter feeders, like the zebra mussel Dreissena polymorpha, an invasive organism in North American and European freshwater ecosystems. A laboratory batch experiment exposing D. polymorpha (∼1200 organisms per m(2)) to organic sediment from a site contaminated with arsenic, copper, lead, and uranium revealed a significant uptake and accumulation of arsenic, copper, iron, and especially uranium both into the soft body tissues and the seashell. This is in line with previous observations of metal(loid) accumulation from biomonitoring studies. Regarding its environmental impact, D. polymorpha significantly contributed to mobilization of silicon, iron, phosphorus, arsenic, and copper and to immobilization of uranium (p < 0.001), probably driven by redox conditions, microbial activity within the gut system, or active control of element homeostasis. No net mobilization or immobilization was observed for zinc and lead, because of their low mobility at the prevailing pH of 7.5-8.5. The present results suggest that D. polymorpha can both ameliorate (nutrient mobilization, immobilization of toxicants mobile under oxic conditions) or aggravate negative effects (mobilization of toxicants mobile under reducing conditions) in ecosystems. Relating the results of the present study to observed population densities in natural freshwater ecosystems suggests a significant influence of D. polymorpha on element cycling and needs to be considered in future studies.

  15. Challenges in researching violence affecting health service delivery in complex security environments.

    PubMed

    Foghammar, Ludvig; Jang, Suyoun; Kyzy, Gulzhan Asylbek; Weiss, Nerina; Sullivan, Katherine A; Gibson-Fall, Fawzia; Irwin, Rachel

    2016-08-01

    Complex security environments are characterized by violence (including, but not limited to "armed conflict" in the legal sense), poverty, environmental disasters and poor governance. Violence directly affecting health service delivery in complex security environments includes attacks on individuals (e.g. doctors, nurses, administrators, security guards, ambulance drivers and translators), obstructions (e.g. ambulances being stopped at checkpoints), discrimination (e.g. staff being pressured to treat one patient instead of another), attacks on and misappropriation of health facilities and property (e.g. vandalism, theft and ambulance theft by armed groups), and the criminalization of health workers. This paper examines the challenges associated with researching the context, scope and nature of violence directly affecting health service delivery in these environments. With a focus on data collection, it considers how these challenges affect researchers' ability to analyze the drivers of violence and impact of violence. This paper presents key findings from two research workshops organized in 2014 and 2015 which convened researchers and practitioners in the fields of health and humanitarian aid delivery and policy, and draws upon an analysis of organizational efforts to address violence affecting healthcare delivery and eleven in-depth interviews with representatives of organizations working in complex security environments. Despite the urgency and impact of violence affecting healthcare delivery, there is an overall lack of research that is of health-specific, publically accessible and comparable, as well as a lack of gender-disaggregated data, data on perpetrator motives and an assessment of the 'knock-on' effects of violence. These gaps limit analysis and, by extension, the ability of organizations operating in complex security environments to effectively manage the security of their staff and facilities and to deliver health services. Increased research

  16. Atmosphere-Forest Exchange: Important Questions Regarding the Atmosphere's Role in the Delivery of Nutrient Nitrogen and Impacts on Nitrogen and Carbon Cycling

    NASA Astrophysics Data System (ADS)

    Carroll, M.; Shepson, P. B.; Bertman, S. B.; Sparks, J. P.; Holland, E. A.

    2002-12-01

    Atmosphere-Forest Exchange: Important Questions Regarding the Atmosphere's Role in the Delivery of Nutrient Nitrogen and Impacts on Nitrogen and Carbon Cycling Atmospheric composition and chemistry directly affect ecosystem nitrogen cycling and indirectly affect ecosystem carbon cycling and storage. Current understanding of atmosphere-forest nitrogen exchange and subsequent impacts is based almost exclusively on nitrogen deposition data obtained from networks using buckets placed in open areas, studies involving inorganic nitrogen, frequently with enhanced N deposition inputs applied only to soils, and that ignore multiple stresses (e.g., the combined effects of aerosols, ozone exposure, elevated CO2, and drought). Current models of nitrogen cycling treat deposited nitrogen (e.g., HNO3 and NO3-) as a permanent sink whereas data appear to indicate that photolytic and heterogeneous chemical processes occurring on surfaces and in dew can result in the re-evolution of gaseous species such as NO and HONO. Similarly, the direct uptake of gaseous nitrogen compounds by foliage has been neglected, compromising conclusions drawn from deposition experiments and ignoring a mechanism that may significantly affect nitrogen cycling and carbon storage, one that may become more significant with future atmospheric and climate change. We hypothesize that the atmosphere plays a significant role in the delivery of nutrient nitrogen to the N-limited mixed hardwood forest at the PROPHET research site at the University of Michigan Biological Station. We assert that a complete understanding of atmosphere- biosphere interactions and feedbacks is required to develop a predictive capability regarding forest response to increasing atmospheric CO2, reactive nitrogen, oxidants, and aerosols, increasing nitrogen and acidic deposition, and anticipated climate change. We further assert that conclusions drawn from studies that are limited to inorganic nitrogen, fertilization of soils, and/or that

  17. Acute interval exercise intensity does not affect appetite and nutrient preferences in overweight and obese males.

    PubMed

    Alkahtani, Shaea A; Byrne, Nuala M; Hills, Andrew P; King, Neil A

    2014-01-01

    This study investigated the influence of two different intensities of acute interval exercise on food preferences and appetite sensations in overweight and obese men. Twelve overweight/obese males (age=29.0±4.1 years; BMI =29.1±2.4 kg/m2) completed three exercise sessions: an initial graded exercise test, and two interval cycling sessions: moderate-(MIIT) and high-intensity (HIIT) interval exercise sessions on separate days in a counterbalanced order. The MIIT session involved cycling for 5-minute repetitions of alternate workloads 20% below and 20% above maximal fat oxidation. The HIIT session consisted of cycling for alternate bouts of 15 seconds at 85% VO2max and 15 seconds unloaded recovery. Appetite sensations and food preferences were measured immediately before and after the exercise sessions using the Visual Analogue Scale and the Liking & Wanting experimental procedure. Results indicated that liking significantly increased and wanting significantly decreased in all food categories after both MIIT and HIIT. There were no differences between MIIT and HIIT on the effect on appetite sensations and Liking & Wanting. In conclusion, manipulating the intensity of acute interval exercise did not affect appetite and nutrient preferences.

  18. Nutrient transport in runoff as affected by diet, tillage and manure application rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Including distillers grains in feedlot finishing diets may increase feedlot profitability. However the nutrient content of by-products are concentrated about three during the distillation process. Manure can be applied to meet single or multiple year crop nutrient requirements. The water quality eff...

  19. Nutrient loads and sediment losses in sprinkler irrigation runoff affected by compost and manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High water application rates beneath the outer spans of center pivot sprinkler systems can cause runoff, erosion, and nutrient losses, particularly from sloping fields. This study determined runoff, sediment losses, and loads of nutrients (dissolved organic C, Nitrate-N, ammonium-N, total phosphoru...

  20. Nutrient demand interacts with forage family to affect digestion responses in dairy cows.

    PubMed

    Kammes, K L; Allen, M S

    2012-06-01

    Effects of forage family on dry matter intake (DMI), milk production, ruminal pool sizes, digestion and passage kinetics, and chewing activity and the relationship of these effects with preliminary DMI (pDMI), an index of nutrient demand, were evaluated using 13 ruminally and duodenally cannulated Holstein cows in a crossover design with a 14-d preliminary period and two 18-d treatment periods. During the preliminary period, pDMI of individual cows ranged from 19.6 to 29.5 kg/d (mean=25.9 kg/d) and 3.5% fat-corrected milk yield ranged from 24.3 to 60.3 kg/d (mean=42.1 kg/d). Experimental treatments were diets containing either a) alfalfa silage (AL) or b) orchardgrass silage (OG) as the sole forage. Alfalfa and orchardgrass contained 42.3 and 58.2% neutral detergent fiber (NDF) and 22.5 and 11.4% crude protein, respectively. Forage:concentrate ratios were 60:40 and 43:57 for AL and OG, respectively; both diets contained approximately 25% forage NDF and 30% total NDF. Preliminary DMI was determined during the last 4 d of the preliminary period when cows were fed a common diet and used as a covariate. Main effects of forage family and their interaction with pDMI were tested by ANOVA. Forage family and its interaction with pDMI did not affect feed intake, milk yield, or milk composition. The AL diet increased indigestible NDF (iNDF) intake and decreased potentially digestible NDF (pdNDF) intake compared with OG. The AL diet increased ruminal pH, digestion rates of pdNDF and starch, and passage rates of pdNDF and iNDF compared with OG, which affected ruminal digestibility. Passage rate of iNDF was related to pDMI; AL increased iNDF passage rate and OG decreased it as pDMI increased. The AL diet decreased ruminal pool sizes of pdNDF, starch, organic matter, dry matter, and rumen digesta wet weight and volume compared with OG. The AL diet decreased ruminating time per unit of forage NDF consumed compared with OG, indicating that alfalfa provided less physically effective

  1. Ultraviolet-B radiation and nitrogen affect nutrient concentrations and the amount of nutrients acquired by above-ground organs of maize.

    PubMed

    Correia, Carlos M; Coutinho, João F; Bacelar, Eunice A; Gonçalves, Berta M; Björn, Lars Olof; Moutinho Pereira, José

    2012-01-01

    UV-B radiation effects on nutrient concentrations in above-ground organs of maize were investigated at silking and maturity at different levels of applied nitrogen under field conditions. The experiment simulated a 20% stratospheric ozone depletion over Portugal. At silking, UV-B increased N, K, Ca, and Zn concentrations, whereas at maturity Ca, Mg, Zn, and Cu increased and N, P and Mn decreased in some plant organs. Generally, at maturity, N, Ca, Cu, and Mn were lower, while P, K, and Zn concentrations in stems and nitrogen-use efficiency (NUE) were higher in N-starved plants. UV-B and N effects on shoot dry biomass were more pronounced than on nutrient concentrations. Nutrient uptake decreased under high UV-B and increased with increasing N application, mainly at maturity harvest. Significant interactions UV-B x N were observed for NUE and for concentration and mass of some elements. For instance, under enhanced UV-B, N, Cu, Zn, and Mn concentrations decreased in leaves, except on N-stressed plants, whereas they were less affected by N nutrition. In order to minimize nutritional, economical, and environmental negative consequences, fertiliser recommendations based on element concentration or yield goals may need to be adjusted.

  2. Ruminant nutrition from an environmental perspective: factors affecting whole-farm nutrient balance.

    PubMed

    Van Horn, H H; Newton, G L; Kunkle, W E

    1996-12-01

    Nutrient budgeting strategies focus primarily on recycling manure to land as fertilizer for crop production. Critical elements for determining environmental balance and accountability require knowledge of nutrients excreted, potential nutrient removal by plants, acceptable losses of nutrients within the manure management and crop production systems, and alternatives that permit export of nutrients off-farm, if necessary. Nutrient excretions are closely related to nutrient intake and can be predicted by subtracting predicted nutrients in food animal products exported from the farm from total nutrients consumed. Intensifying crop production with double- or triple-cropping often is necessary for high-density food animal production units to use manure without being forced to export manure or fertilizer coproducts to other farms. Most manures are P-rich relative to N largely because of 1) relatively large losses of volatilized NH3, most of it converted from urea in urine, 2) denitrification losses in soil under wet, anaerobic conditions, and 3) ability of many crops to luxury-consume much more N than P. Most soils bind P effectively and P usually is permitted to accumulate, allowing for budgets to be based on N. However, P budgeting may be required in regions where surface runoff of P contributes to algae growth and eutrophication of surface waters or where soil P increases to levels of concern. Research is needed to determine whether dietary P allowances can be lowered without detriment to animal production or health in order to lower P intake and improve N:P ratios in manure relative to fertilization needs.

  3. Thermal acclimation and nutritional history affect the oxidation of different classes of exogenous nutrients in Siberian hamsters, Phodopus sungorus.

    PubMed

    McCue, Marshall D; Voigt, Christian C; Jefimow, Małgorzata; Wojciechowski, Michał S

    2014-11-01

    During acclimatization to winter, changes in morphology and physiology combined with changes in diet may affect how animals use the nutrients they ingest. To study (a) how thermal acclimation and (b) nutritional history affect the rates at which Siberian hamsters (Phodopus sungorus) oxidize different classes of dietary nutrients, we conducted two trials in which we fed hamsters one of three (13) C-labeled compounds, that is, glucose, leucine, or palmitic acid. We predicted that under acute cold stress (3 hr at 2°C) hamsters previously acclimated to cold temperatures (10°C) for 3 weeks would have higher resting metabolic rate (RMR) and would oxidize a greater proportion of dietary fatty acids than animals acclimated to 21°C. We also investigated how chronic nutritional stress affects how hamsters use dietary nutrients. To examine this, hamsters were fed four different diets (control, low protein, low lipid, and low-glycemic index) for 2 weeks. During cold challenges, hamsters previously acclimated to cold exhibited higher thermal conductance and RMR, and also oxidized more exogenous palmitic acid during the postprandial phase than animals acclimated to 21°C. In the nutritional stress trial, hamsters fed the low protein diet oxidized more exogenous glucose, but not more exogenous palmitic acid than the control group. The use of (13) C-labeled metabolic tracers combined with breath testing demonstrated that both thermal and nutritional history results in significant changes in the extent to which animals oxidize dietary nutrients during the postprandial period.

  4. Nutritional, physical, and sensory evaluation of hydroponic carrots (Daucus carota L.) from different nutrient delivery systems.

    PubMed

    Gichuhi, P N; Mortley, D; Bromfield, E; Bovell-Benjamin, A C

    2009-01-01

    Carrot (Daucus carota L.) has the highest carotenoid content among foods and is consumed in large quantities worldwide, while at the same time its market demand continues to increase. Carotenoids have also been associated with protective effects against cancer and other chronic diseases. The most predominant carotenoids in carrots are beta- and alpha-carotenes. Moisture, ash, fat, texture, color, carotene content, and consumer acceptance of carrots grown in a hydroponic system with nutrient film technique (NFT) and microporous tube membrane system (MTMS) were evaluated. The moisture contents of the NFT- and MTMS-grown carrots ranged from 86.8 +/- 0.13% to 92.2 +/- 2.25% and 80.9 +/- 0.31% to 91.6 +/- 1.01%, respectively. Fat and ash contents of the carrots were negligible. NFT-grown Oxheart had the most beta-carotene (9900 +/- 20 microg/100 g) while Juwaroot had the least (248 +/- 10 microg/100 g). However, the beta-carotene content of Juwaroot from the NFT batch II carrots was 3842 +/- 6 microg/100 g. MTMS-grown carrots had less variation in the total beta-carotene contents (2434 +/- 89 to 10488 +/- 8 microg/100 g) than those from NFT. Overall, Nantes Touchan (4.8 +/- 2.3) and Nevis-F (7 +/- 1.4) from NFT were the least and most preferred by consumers. Mignon was also acceptable to consumers, and significantly (P < 0.05) more preferred than the other carrots in that NFT batch. MTMS-grown Kinko and Paramex, which were significantly (P < 0.05) more preferred than Nandrin-F and the commercial field-grown carrot, were equally liked by consumers. Nevis-F, Mignon (NFT), Paramex, and Kinko (MTMS) are potentially good cultivars to be included in NASA's food system.

  5. Upland disturbance affects headwater stream nutrients and suspended sediments during baseflow and stormflow

    USGS Publications Warehouse

    Houser, J.N.; Mulholland, P.J.; Maloney, K.O.

    2006-01-01

    Because catchment characteristics determine sediment and nutrient inputs to streams, upland disturbance can affect stream chemistry. Catchments at the Fort Benning Military Installation (near Columbus, Georgia) experience a range of upland disturbance intensities due to spatial variability in the intensity of military training. We used this disturbance gradient to investigate the effects of upland soil and vegetation disturbance on stream chemistry. During baseflow, mean total suspended sediment (TSS) concentration and mean inorganic suspended sediment (ISS) concentration increased with catchment disturbance intensity (TSS: R2 = 0.7, p = 0.005, range = 4.0-10.1 mg L-1; ISS: R2 = 0.71, p = 0.004, range = 2.04-7.3 mg L-1); dissolved organic carbon (DOC) concentration (R2 = 0.79, p = 0.001, range = 1.5-4.1 mg L-1) and soluble reactive phosphorus (SRP) concentration (R2 = 0.75, p = 0.008, range = 1.9-6.2 ??g L-1) decreased with increasing disturbance intensity; and ammonia (NH 4+), nitrate (NO3-), and dissolved inorganic nitrogen (DIN) concentrations were unrelated to disturbance intensity. The increase in TSS and ISS during storms was positively correlated with disturbance (R2 = 0.78 and 0.78, p = 0.01 and 0.01, respectively); mean maximum change in SRP during storms increased with disturbance (r = 0.7, p = 0.04); and mean maximum change in NO3- during storms was marginally correlated with disturbance (r = 0.58, p = 0.06). Soil characteristics were significant predictors of baseflow DOC, SRP, and Ca 2+, but were not correlated with suspended sediment fractions, any nitrogen species, or pH. Despite the largely intact riparian zones of these headwater streams, upland soil and vegetation disturbances had clear effects on stream chemistry during baseflow and stormflow conditions. ?? ASA, CSSA, SSSA.

  6. Upland disturbance affects headwater stream nutrients and suspended sediments during baseflow and stormflow

    SciTech Connect

    Houser, Jeffrey N

    2006-01-01

    Because catchment characteristics determine sediment and nutrient inputs to streams, upland disturbance can affect stream chemistry. Catchments at the Fort Benning Military Installation (near Columbus, Georgia) experience a range of upland disturbance intensities due to spatial variability in the intensity of military training. We used this disturbance gradient to investigate the effects of upland soil and vegetation disturbance on stream chemistry. During baseflow, mean total suspended sediment (TSS) concentration and mean inorganic suspended sediment (ISS) concentration increased with catchment disturbance intensity (TSS: R 2 = 0.7, p = 0.005, range = 4.0-10.1 mg L-1; ISS: R 2 = 0.71, p = 0.004, range = 2.04-7.3 mg L-1); dissolved organic carbon (DOC) concentration (R 2 = 0.79, p = 0.001, range = 1.5-4.1 mg L-1) and soluble reactive phosphorus (SRP) concentration (R 2 = 0.75, p = 0.008, range = 1.9-6.2 {micro}g L-1) decreased with increasing disturbance intensity; and ammonia (NH4 +), nitrate (NO3 -), and dissolved inorganic nitrogen (DIN) concentrations were unrelated to disturbance intensity. The increase in TSS and ISS during storms was positively correlated with disturbance (R 2 = 0.78 and 0.78, p = 0.01 and 0.01, respectively); mean maximum change in SRP during storms increased with disturbance (r = 0.7, p = 0.04); and mean maximum change in NO3 - during storms was marginally correlated with disturbance (r = 0.58, p = 0.06). Soil characteristics were significant predictors of baseflow DOC, SRP, and Ca2+, but were not correlated with suspended sediment fractions, any nitrogen species, or pH. Despite the largely intact riparian zones of these headwater streams, upland soil and vegetation disturbances had clear effects on stream chemistry during baseflow and stormflow conditions.

  7. Nutrient addition differentially affects ecological processes of Avicennia germinans in nitrogen versus phosphorus limited mangrove ecosystems

    USGS Publications Warehouse

    Feller, Ilka C.; Lovelock, C.E.; McKee, K.L.

    2007-01-01

    Nutrient over-enrichment is a major threat to marine environments, but system-specific attributes of coastal ecosystems may result in differences in their sensitivity and susceptibility to eutrophication. We used fertilization experiments in nitrogen (N)- and phosphorus (P)-limited mangrove forests to test the hypothesis that alleviating different kinds of nutrient limitation may have different effects on ecosystem structure and function in natural systems. We compared a broad range of ecological processes to determine if these systems have different thresholds where shifts might occur in nutrient limitation. Growth responses indicated N limitation in Avicennia germinans (black mangrove) forests in the Indian River Lagoon (IRL), Florida, and P limitation at Twin Cays, Belize. When nutrient deficiency was relieved, A. germinans grew out of its stunted form by increasing wood relative to leaf biomass and shoot length relative to lateral growth. At the P-limited site, P enrichment (+P) increased specific leaf area, N resorption, and P uptake, but had no effect on P resorption. At the N-limited site, +N increased both N and P resorption, but did not alter biomass allocation. Herbivory was greater at the P-limited site and was unaffected by +P, whereas +N led to increased herbivory at the N-limited site. The responses to nutrient enrichment depended on the ecological process and limiting nutrient and suggested that N- versus P-limited mangroves do have different thresholds. +P had a greater effect on more ecological processes at Twin Cays than did +N at the IRL, which indicated that the P-limited site was more sensitive to nutrient loading. Because of this sensitivity, eutrophication is more likely to cause a shift in nutrient limitation at P-limited Twin Cays than N-limited IRL. ?? 2007 Springer Science+Business Media, LLC.

  8. Factors Affecting Nitrate Delivery to Streams from Shallow Ground Water in the North Carolina Coastal Plain

    USGS Publications Warehouse

    Harden, Stephen L.; Spruill, Timothy B.

    2008-01-01

    An analysis of data collected at five flow-path study sites between 1997 and 2006 was performed to identify the factors needed to formulate a comprehensive program, with a focus on nitrogen, for protecting ground water and surface water in the North Carolina Coastal Plain. Water-quality protection in the Coastal Plain requires the identification of factors that affect the transport of nutrients from recharge areas to streams through the shallow ground-water system. Some basins process or retain nitrogen more readily than others, and the factors that affect nitrogen processing and retention were the focus of this investigation to improve nutrient management in Coastal Plain streams and to reduce nutrient loads to coastal waters. Nitrate reduction in ground water was observed at all five flow-path study sites in the North Carolina Coastal Plain, although the extent of reduction at each site was influenced by various environmental, hydrogeologic, and geochemical factors. Denitrification was the most common factor responsible for decreases in nitrate along the ground-water flow paths. Specific factors, some of which affect denitrification rates, that appeared to influence ground-water nitrate concentrations along the flow paths or in the streams include soil drainage, presence or absence of riparian buffers, evapotranspiration, fertilizer use, ground-water recharge rates and residence times, aquifer properties, subsurface tile drainage, sources and amounts of organic matter, and hyporheic processes. The study data indicate that the nitrate-reducing capacity of the buffer zone combined with that of the hyporheic zone can substantially lower the amount of ground-water nitrate discharged to streams in agricultural settings of the North Carolina Coastal Plain. At the watershed scale, the effects of ground-water discharge on surface-water quality appear to be greatly influenced by streamflow conditions and the presence of extensive riparian vegetation. Streamflow statistics

  9. Dietary L-carnitine affects periparturient nutrient metabolism and lactation in multiparous cows.

    PubMed

    Carlson, D B; McFadden, J W; D'Angelo, A; Woodworth, J C; Drackley, J K

    2007-07-01

    The objectives of this study were to determine the effects of dietary L-carnitine supplementation on liver lipid accumulation, hepatic nutrient metabolism, and lactation in multiparous cows during the periparturient period. Cows were assigned to treatments at d -25 relative to expected calving date and remained on the experiment until 56 d in milk. Treatments were 4 amounts of supplemental dietary carnitine: control (0 g/d of L-carnitine; n = 14); low carnitine (LC, 6 g/d; n = 11); medium carnitine (MC, 50 g/d; n = 12); and high carnitine (HC, 100 g/d; n = 12). Carnitine was supplied by mixing a feed-grade carnitine supplement with 113.5 g of ground corn and 113.5 g of dried molasses, which was then fed twice daily as a topdress to achieve desired daily carnitine intakes. Carnitine supplementation began on d -14 relative to expected calving and continued until 21 d in milk. Liver and muscle carnitine concentrations were markedly increased by MC and HC treatments. Milk carnitine concentrations were elevated by all amounts of carnitine supplementation, but were greater for MC and HC than for LC during wk 2 of lactation. Dry matter intake and milk yield were decreased by the HC treatment. The MC and HC treatments increased milk fat concentration, although milk fat yield was unaffected. All carnitine treatments decreased liver total lipid and triacylglycerol accumulation on d 10 after calving. In addition, carnitine-supplemented cows had higher liver glycogen during early lactation. In general, carnitine supplementation increased in vitro palmitate beta-oxidation by liver slices, with MC and HC treatments affecting in vitro palmitate metabolism more potently than did LC. In vitro conversion of Ala to glucose by liver slices was increased by carnitine supplementation independent of dose. The concentration of nonesterified fatty acids in serum was not affected by carnitine. As a result of greater hepatic fatty acid beta-oxidation, plasma beta-hydroxybutyric acid was

  10. Source and Delivery of Nutrients to Receiving Waters in the Northeastern and Mid-Atlantic Regions of the United States1

    PubMed Central

    Moore, Richard B; Johnston, Craig M; Smith, Richard A; Milstead, Bryan

    2011-01-01

    Abstract This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake. PMID:22457578

  11. Engineering strategies for the design of plant nutrient delivery systems for use in space: approaches to countering microbiological contamination.

    PubMed

    Gonzales, A A; Schuerger, A C; Barford, C; Mitchell, R

    1996-01-01

    Microbiological contamination of crops within space-based plant growth research chambers has been postulated as a potentially significant problem. Microbial infestations; fouling of Nutrient Delivery System (NDS) fluid loops; and the formation of biofilms have been suggested as the most obvious and important manifestations of the problem. Strict sanitation and quarantine procedures will reduce, but not eliminate, microbial species introduced into plant growth systems in space habitats. Microorganisms transported into space most likely will occur as surface contaminants on spacecraft components, equipment, the crew, and plant-propagative materials. Illustrations of the potential magnitude of the microbiological contamination issue will be drawn from the literature and from documentation of laboratory and commercial field experience. Engineering strategies for limiting contamination and for the development of countermeasures will be described. Microbiological control technologies and NDS hardware will be discussed. Configurations appropriate for microgravity research facilities, as well as anticipated bio-regenerative life support system implementations, will be explored. An efficiently designed NDS, capable of adequately meeting the environmental needs of crop plants in space, is considered to be critical in both the research and operational domains. Recommended experiments, tests, and technology developments, structured to allow the development of prudent engineering solutions also will be presented.

  12. Engineering strategies for the design of plant nutrient delivery systems for use in space: approaches to countering microbiological contamination

    NASA Technical Reports Server (NTRS)

    Gonzales, A. A.; Schuerger, A. C.; Barford, C.; Mitchell, R.

    1996-01-01

    Microbiological contamination of crops within space-based plant growth research chambers has been postulated as a potentially significant problem. Microbial infestations; fouling of Nutrient Delivery System (NDS) fluid loops; and the formation of biofilms have been suggested as the most obvious and important manifestations of the problem. Strict sanitation and quarantine procedures will reduce, but not eliminate, microbial species introduced into plant growth systems in space habitats. Microorganisms transported into space most likely will occur as surface contaminants on spacecraft components, equipment, the crew, and plant-propagative materials. Illustrations of the potential magnitude of the microbiological contamination issue will be drawn from the literature and from documentation of laboratory and commercial field experience. Engineering strategies for limiting contamination and for the development of countermeasures will be described. Microbiological control technologies and NDS hardware will be discussed. Configurations appropriate for microgravity research facilities, as well as anticipated bio-regenerative life support system implementations, will be explored. An efficiently designed NDS, capable of adequately meeting the environmental needs of crop plants in space, is considered to be critical in both the research and operational domains. Recommended experiments, tests, and technology developments, structured to allow the development of prudent engineering solutions also will be presented.

  13. Engineering Strategies for the Design of Plant Nutrient Delivery Systems for Use in Space: Approaches to Countering Microbiological Contamination

    NASA Technical Reports Server (NTRS)

    Gonzales, A. A.; Schuerger, A. C.; Mitchell, R.; Harper, Lynn D. (Technical Monitor)

    1994-01-01

    Microbiological contamination of crops within space-based crop growth research chambers has been postulated as a potentially significant problem. Microbial infestations; fouling of Nutrient Delivery System (NDS) fluid loops; and the formation of biofilms, have been suggested as the most obvious and important manifestations of the problem. Strict sanitation and quarantine procedures will reduce, but not eliminate, microbial species introduced into plant growing systems in space habitats. Microorganisms transported into space will most likely occur as contaminants on spacecraft components, equipment, the crew, and plant-propagative materials. Illustrations of the potential magnitude of the microbiological contamination issue will be drawn from the literature and from documentation of laboratory and commercial field experience. Engineering strategies for limiting contamination and for the development of countermeasures will be described. Microbiological control technologies and NDS hardware will be discussed. Configurations appropriate for microgravity research facilities, as well as anticipated bio-regenerative life support system implementations, will be explored. An efficiently designed NDS, capable of adequately meeting the environmental needs of crop plants in space, is considered to be critical in both the research and operational domains. Recommended experiments, tests and technology developments, structured to allow the development of prudent engineering solutions, will also be presented.

  14. Engineering strategies for the design of plant nutrient delivery systems for use in space: approaches to countering microbiological contamination

    NASA Astrophysics Data System (ADS)

    Gonzales, A. A.; Schuerger, A. C.; Barford, C.; Mitchell, R.

    Microbiological contamination of crops within space-based plant growth research chambers has been postulated as a potentially significant problem. Microbial infestations; fouling of Nutrient Delivery System (NDS) fluid loops; and the formation of biofilms have been suggested as the most obvious and important manifestations of the problem. Strict sanitation and quarantine procedures will reduce, but not eliminate, microbial species introduced into plant growth systems in space habitats. Microorganisms transported into space most likely will occur as surface contaminants on spacecraft components, equipment, the crew, and plant-propagative materials. Illustrations of the potential magnitude of the microbiological contamination issue will be drawn from the literature and from documentation of laboratory and commercial field experience. Engineering strategies for limiting contamination and for the development of countermeasures will be described. Microbiological control technologies and NDS hardware will be discussed. Configurations appropriate for microgravity research facilities, as well as anticipated bio-regenerative life support system implementations, will be explored. An efficiently designed NDS, capable of adequately meeting the environmental needs of crop plants in space, is considered to be critical in both the research and operational domains. Recommended experiments, tests, and technology developments, structured to allow the development of prudent engineering solutions also will be presented.

  15. Delivery

    PubMed Central

    Miller, Thomas A

    2013-01-01

    Enthusiasm greeted the development of synthetic organic insecticides in the mid-twentieth century, only to see this give way to dismay and eventually scepticism and outright opposition by some. Regardless of how anyone feels about this issue, insecticides and other pesticides have become indispensable, which creates something of a dilemma. Possibly as a result of the shift in public attitude towards insecticides, genetic engineering of microbes was first met with scepticism and caution among scientists. Later, the development of genetically modified crop plants was met with an attitude that hardened into both acceptance and hard-core resistance. Transgenic insects, which came along at the dawn of the twenty-first century, encountered an entrenched opposition. Those of us responsible for studying the protection of crops have been affected more or less by these protagonist and antagonistic positions, and the experiences have often left one thoughtfully mystified as decisions are made by non-participants. Most of the issues boil down to concerns over delivery mechanisms. © 2013 Society of Chemical Industry PMID:23852646

  16. Plant growth-promoting rhizobacteria affect the growth and nutrient uptake of Fraxinus americana container seedlings.

    PubMed

    Liu, Fangchun; Xing, Shangjun; Ma, Hailin; Du, Zhenyu; Ma, Bingyao

    2013-05-01

    Plant growth-promoting rhizobacteria (PGPR) are important catalysts that regulate the functional properties of agricultural systems. However, there is little information on the effect of PGPR inoculation on the growth and nutrient accumulation of forest container seedlings. This study determined the effects of a growth medium inoculated with PGPR on the nutrient uptake, nutrient accumulation, and growth of Fraxinus americana container seedlings. PGPR inoculation with fertilizer increased the dry matter accumulation of the F. americana aerial parts with delayed seedling emergence time. Under fertilized conditions, the accumulation time of phosphorous (P) and potassium (K) in the F. americana aerial parts was 13 days longer due to PGPR inoculation. PGPR increased the maximum daily P and K accumulations in fertilized seedlings by 9.31 and 10.44 %, respectively, but had little impact on unfertilized ones. Regardless of fertilizer application, the root exudates, namely sugars, amino acids, and organic acids significantly increased because of PGPR inoculation. PGPR inoculation with fertilizer increased the root, shoot, and leaf yields by 19.65, 22.94, and 19.44 %, respectively, as well as the P and K contents by 8.33 and 10.60 %, respectively. Consequently, the N, P, and K uptakes increased by 19.85, 31.97, and 33.95 %, respectively. Hence, PGPR inoculation with fertilizer can be used as a bioenhancer for plant growth and nutrient uptake in forest container seedling nurseries.

  17. Nutrient concentrations of runoff as affected by the diameter of unconsolidated material from feedlot surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beef cattle feedlots contain unconsolidated material that accumulates on the feedlot surface during a feeding cycle. This study was conducted to measure the effects of varying diameters of unconsolidated surface material and varying flow rates on nutrient concentrations in runoff. Unconsolidated sur...

  18. Runoff nutrient transport as affected by land application method, swine growth stage, and runoff rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to measure the effects of slurry application method, swine growth stage, and flow rate on runoff nutrient transport. Swine slurry was obtained from production units containing grower pigs, finisher pigs, or sows and gilts. The swine slurry was applied using broadcast, disk, ...

  19. Runoff nutrient loads as affected by residue cover, manure application rate, and flow rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Manure is applied to cropland areas with varying surface cover to meet single- or multiple-year crop nutrient requirements. The objectives of this field study were to (1) examine runoff water quality characteristics following land application of manure to sites with and without wheat residue, (2) co...

  20. Relationships Among Watershed Condition, Nutrients, and Algae in New England Streams Affected by Urbanization

    EPA Science Inventory

    We examined algal metrics as indicators of altered watershed land cover and nutrients to inform their potential use in monitoring programs. Multiple regression models, in which impervious cover explained the most variation, indicated concentrations <0.202 mg/l NO3 and <0.015 mg/l...

  1. Carrot, Corn, Lettuce and Soybean Nutrient Contents are Affected by Biochar

    EPA Science Inventory

    Biochar, the carbon-rich material remaining after pyrolysis of cellulosic and manure feedstocks, has the potential as a soil amendment to sequester carbon and to improve soil water-holding and nutrient properties- thereby enhancing plant growth. However, biochar produced from so...

  2. Maternal investment and nutrient use affect phenotype of American alligator and domestic chicken hatchlings.

    PubMed

    Nelson, Thomas C; Groth, Kevin D; Sotherland, Paul R

    2010-09-01

    Maternal investment by oviparous amniotes, in the form of yolk and albumen, and the mechanisms by which embryos use available energy and nutrients have a profound effect on embryo and, consequently, hatchling phenotype. Nutrient provisioning and uptake vary within and among oviparous taxa, avian and non-avian reptiles, due to differences and similarities in environment, behavior, and phylogeny. Eggs of crocodilians, the closest extant relatives to modern birds, are ideal models for examining modes of embryonic development, especially with regard to nutrient uptake, in non-avian reptiles and comparing them with those of birds. In this study, we investigated egg composition, embryo growth, and nutrient use in the domestic chicken (Gallus gallus) and American alligator (Alligator mississippiensis). We explored egg composition by separating and weighing components of fresh eggs. We measured embryo growth and nutrient usage by dissecting embryos and by obtaining samples of liquid from the amnion, digestive tract, and yolk sac throughout the last half of incubation. Variation in albumen mass contributed most to egg mass variation in chicken eggs, whereas alligator eggs were composed almost equally of yolk and albumen, although larger eggs contained proportionally more albumen and less yolk than smaller eggs. Both chicken and alligator albumen were mostly water (87% and 96%, respectively) although chicken albumen contained over three times more solid mass per gram than alligator albumen. In both species, yolk contained a high proportion of solids. Larger eggs produced larger hatchlings in both chickens and alligators, but albumen solids contributed to embryo mass only in chicken embryos. However, intact albumen proteins appeared in the stomach in embryos of both species. While the final disposition of albumen in alligators is unclear, variation in maternal investment of yolk at oviposition was responsible for nearly all of the variation in alligator hatchling phenotype

  3. Development of Upper Respiratory Tract Microbiota in Infancy is Affected by Mode of Delivery.

    PubMed

    Bosch, Astrid A T M; Levin, Evgeni; van Houten, Marlies A; Hasrat, Raiza; Kalkman, Gino; Biesbroek, Giske; de Steenhuijsen Piters, Wouter A A; de Groot, Pieter-Kees C M; Pernet, Paula; Keijser, Bart J F; Sanders, Elisabeth A M; Bogaert, Debby

    2016-07-01

    Birth by Caesarian section is associated with short- and long-term respiratory morbidity. We hypothesized that mode of delivery affects the development of the respiratory microbiota, thereby altering its capacity to provide colonization resistance and consecutive pathobiont overgrowth and infections. Therefore, we longitudinally studied the impact of mode of delivery on the nasopharyngeal microbiota development from birth until six months of age in a healthy, unselected birth cohort of 102 children (n=761 samples). Here, we show that the respiratory microbiota develops within one day from a variable mixed bacterial community towards a Streptococcus viridans-predominated profile, regardless of mode of delivery. Within the first week, rapid niche differentiation had occurred; initially with in most infants Staphylococcus aureus predominance, followed by differentiation towards Corynebacterium pseudodiphteriticum/propinquum, Dolosigranulum pigrum, Moraxella catarrhalis/nonliquefaciens, Streptococcus pneumoniae, and/or Haemophilus influenzae dominated communities. Infants born by Caesarian section showed a delay in overall development of respiratory microbiota profiles with specifically reduced colonization with health-associated commensals like Corynebacterium and Dolosigranulum, thereby possibly influencing respiratory health later in life.

  4. Hydroperiod affects nutrient accumulation in tree islands of the Florida Everglades: a stable isotope study

    NASA Astrophysics Data System (ADS)

    Wang, X.; Sternberg, L. O.; Engel, V.; Ross, M. S.

    2009-12-01

    Tree islands are important and unique components of wetland ecosystems. In many cases they are the end product of self organizing vegetation systems, which are often characterized by uneven soil nutrient distributions. Tree islands in the Everglades are phosphorus rich in contrast to the phosphorus-poor surrounding vegetation matrix. Everglades tree islands occur in the ridge-slough habitat of Shark River Slough, which is characterized by deep organic soils, multi-year hydroperiods, and maximum water depths of ~ 1 m. Tree islands are also found in the drier marl prairie habitat of the Everglades, characterized by marl soils, shallow water (< 0.5 m) and short (< 180 day) hydroperiods. In this study we used stable isotopes to investigate dry season water limitation and soil and foliar nutrient status in upland hammock communities of 18 different tree islands located in the Shark River Slough and adjacent prairie landscapes. We observed that prairie tree islands suffer greater drought stress during the dry season than slough tree islands by examining shifts in foliar δ13C values. We also found that slough tree islands have higher soil total phosphorus concentration and lower foliar N/P ratio than prairie tree islands. Foliar δ15N values, which often increase with greater P availability, was also found to be higher in slough tree islands than in prairie tree islands. Both the elemental N and P and foliar δ15N results indicate that the upland hammock plant communities in slough tree islands have higher amount of P available than those in prairie tree islands. Our findings are consistent with the transpiration driven nutrient harvesting chemohydrodynamic model. Tree islands without drought stress hypothetically transpire more and harvest more P than tree islands that have drought stress during the dry season. These findings suggest that hydroperiod is important to nutrient accumulation of tree island habitats and to the self-organization of the Everglades landscape.

  5. Do dietary intakes affect search for nutrient information on food labels?

    PubMed

    Lin, Chung-Tung Jordan; Lee, Jonq-Ying; Yen, Steven T

    2004-11-01

    Nutrition labels on food packages are designed to promote and protect public health by providing nutrition information so that consumers can make informed dietary choices. High levels of total fat, saturated fat and cholesterol in diets are linked to increased blood cholesterol levels and a greater risk of heart disease. Therefore, an understanding of consumer use of total fat, saturated fat, and cholesterol information on food labels has important implications for public health and nutrition education. This study explores the association between dietary intakes of these three nutrients and psychological or demographic factors and the search for total fat, saturated fat, and cholesterol information on food labels. Psychology literature suggests a negative association between intakes of these nutrients and probability of search for their information on food labels. Health behavior theories also suggest perceived benefits and costs of using labels and perceived capability of using labels are associated with the search behavior. We estimate the relationship between label information search and its predictors using logistic regressions. Our samples came from the 1994-1996 Continuing Survey of Food Intakes by Individuals and Diet and Health Knowledge Survey conducted by the United States Department of Agriculture. Results suggest that search for total fat, saturated fat, and cholesterol information on food labels is less likely among individuals who consume more of the three nutrients, respectively. The search is also related to perceived benefits and costs of using the label, perceived capability of using the label, knowledge of nutrition and fats, perceived efficacy of diets in reducing the risk of illnesses, perceived importance of nutrition in food shopping, perceived importance of a healthy diet, and awareness of linkage between excessive consumption of the nutrients and health problems. These findings suggest encouraging search of food label information among

  6. Land use and nutrient inputs affect priming in Andosols of Mt. Kilimanjaro

    NASA Astrophysics Data System (ADS)

    Mganga, Kevin; Kuzyakov, Yakov

    2015-04-01

    Organic C and nutrients additions in soil can accelerate mineralisation of soil organic matter i.e. priming effects. However, only very few studies have been conducted to investigate the priming effects phenomenon in tropical Andosols. Nutrients (N, P, N+P) and 14C labelled glucose were added to Andosols from six natural and intensively used ecosystems at Mt. Kilimanjaro i.e. (1) savannah, (2) maize fields, (3) lower montane forest, (4) coffee plantation, (5) grasslands and (6) Chagga homegardens. Carbon-dioxide emissions were monitored over a 60 days incubation period. Mineralisation of glucose to 14CO2 was highest in coffee plantation and lowest in Chagga homegarden soils. Maximal and minimal mineralisation rates immediately after glucose additions were observed in lower montane forest with N+P fertilisation (9.1% ± 0.83 d -1) and in savannah with N fertilisation (0.9% ± 0.17 d -1), respectively. Glucose and nutrient additions accelerated native soil organic matter mineralisation i.e. positive priming. Chagga homegarden soils had the lowest 14CO2 emissions and incorporated the highest percent of glucose into microbial biomass. 50-60% of the 14C input was retained in soil. We attribute this mainly to the high surface area of non-crystalline constituents i.e. allophanes, present in Andosols and having very high sorption capacity for organic C. The allophanic nature of Andosols of Mt. Kilimanjaro especially under traditional Chagga homegarden agroforestry system shows great potential for providing essential environmental services, notably C sequestration. Key words: Priming Effects, Andosols, Land Use Changes, Mt. Kilimanjaro, Allophanes, Tropical Agroforestry

  7. Yeast mutant affected for viability upon nutrient starvation: characterization and cloning of the RVS161 gene.

    PubMed

    Crouzet, M; Urdaci, M; Dulau, L; Aigle, M

    1991-10-01

    In yeast, nutrient starvation leads to entry into stationary phase. Mutants that do not respond properly to starvation conditions have been isolated in Saccharomyces cerevisiae. Among them the rvs161 mutant (RVS for Reduced Viability upon Starvation) is sensitive to carbon, nitrogen and sulphur starvation. When these nutrients are depleted in the medium, mutant cells show cellular viability loss with morphological changes. The mutation rvs161-1 is very pleiotropic, and besides the defects in stationary phase entry, the mutant strain presents other alterations: sensitivity to high salt concentrations, hypersensitivity to amino acid analogs, no growth on lactate or acetate medium. The addition of salts or amino acid analogs leads to the same morphological defects observed in starved cells, suggesting that the gene could be implicated mainly in the control of cellular viability. The gene RVS161 was cloned; it codes for a 30,252 daltons protein. No homology was detected with the proteins contained in the databases. Moreover, Southern analysis revealed the presence of other sequences homologous to the RVS161 gene in the yeast genome.

  8. Testing an agent-based model of bacterial cell motility: How nutrient concentration affects speed distribution

    NASA Astrophysics Data System (ADS)

    Garcia, V.; Birbaumer, M.; Schweitzer, F.

    2011-08-01

    We revisit a recently proposed agent-based model of active biological motion and compare its predictions with own experimental findings for the speed distribution of bacterial cells, Salmonella typhimurium. Agents move according to a stochastic dynamics and use energy stored in an internal depot for metabolism and active motion. We discuss different assumptions of how the conversion from internal to kinetic energy d( v) may depend on the actual speed, to conclude that d 2 v ξ with either ξ = 2 or 1 < ξ < 2 are promising hypotheses. To test these, we compare the model's prediction with the speed distribution of bacteria which were obtained in media of different nutrient concentration and at different times. We find that both hypotheses are in line with the experimental observations, with ξ between 1.67 and 2.0. Regarding the influence of a higher nutrient concentration, we conclude that the take-up of energy by bacterial cells is indeed increased. But this energy is not used to increase the speed, with 40 μm/s as the most probable value of the speed distribution, but is rather spend on metabolism and growth.

  9. Richness and species composition of arboreal arthropods affected by nutrients and predators: a press experiment.

    PubMed

    Gruner, Daniel S; Taylor, Andrew D

    2006-04-01

    A longstanding goal for ecologists is to understand the processes that maintain biological diversity in communities, yet few studies have investigated the combined effects of predators and resources on biodiversity in natural ecosystems. We fertilized nutrient limited plots and excluded insectivorous birds in a randomized block design, and examined the impacts on arthropods associated with the dominant tree in the Hawaiian Islands, Metrosideros polymorpha (Myrtaceae). After 33 months, the species load (per foliage mass) of herbivores and carnivores increased with fertilization, but rarified richness (standardized to abundance) did not change. Fertilization depressed species richness of arboreal detritivores, and carnivore richness dropped in caged, unfertilized plots, both because of the increased dominance of common, introduced species with treatments. Herbivore species abundance distributions were more equitable than other trophic levels following treatments, and fertilization added specialized native species without changing relativized species richness. Overall, bird removal and nutrient addition treatments on arthropod richness acted largely independently, but with countervailing influences that obscured distinct top-down and bottom-up effects on different trophic levels. This study demonstrates that species composition, biological invasions, and the individuality of species traits may complicate efforts to predict the interactive effects of resources and predation on species diversity in food webs.

  10. Changing nutrient stoichiometry affects phytoplankton production, DOP accumulation and dinitrogen fixation - a mesocosm experiment in the eastern tropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Meyer, J.; Löscher, C. R.; Neulinger, S. C.; Reichel, A. F.; Loginova, A.; Borchard, C.; Schmitz, R. A.; Hauss, H.; Kiko, R.; Riebesell, U.

    2016-02-01

    Ocean deoxygenation due to climate change may alter redox-sensitive nutrient cycles in the marine environment. The productive eastern tropical North Atlantic (ETNA) upwelling region may be particularly affected when the relatively moderate oxygen minimum zone (OMZ) deoxygenates further and microbially driven nitrogen (N) loss processes are promoted. Consequently, water masses with a low nitrogen to phosphorus (N : P) ratio could reach the euphotic layer, possibly influencing primary production in those waters. Previous mesocosm studies in the oligotrophic Atlantic Ocean identified nitrate availability as a control of primary production, while a possible co-limitation of nitrate and phosphate could not be ruled out. To better understand the impact of changing N : P ratios on primary production and N2 fixation in the ETNA surface ocean, we conducted land-based mesocosm experiments with natural plankton communities and applied a broad range of N : P ratios (2.67-48). Silicic acid was supplied at 15 µmol L-1 in all mesocosms. We monitored nutrient drawdown, biomass accumulation and nitrogen fixation in response to variable nutrient stoichiometry. Our results confirmed nitrate to be the key factor determining primary production. We found that excess phosphate was channeled through particulate organic matter (POP) into the dissolved organic matter (DOP) pool. In mesocosms with low inorganic phosphate availability, DOP was utilized while N2 fixation increased, suggesting a link between those two processes. Interestingly this observation was most pronounced in mesocosms where nitrate was still available, indicating that bioavailable N does not necessarily suppress N2 fixation. We observed a shift from a mixed cyanobacteria-proteobacteria dominated active diazotrophic community towards a diatom-diazotrophic association of the Richelia-Rhizosolenia symbiosis. We hypothesize that a potential change in nutrient stoichiometry in the ETNA might lead to a general shift within

  11. Biochar and manure affect calcareous soil and corn silage nutrient concentrations and uptake.

    PubMed

    Lentz, R D; Ippolito, J A

    2012-01-01

    Carbon-rich biochar derived from the pyrolysis of biomass can sequester atmospheric CO, mitigate climate change, and potentially increase crop productivity. However, research is needed to confirm the suitability and sustainability of biochar application to different soils. To an irrigated calcareous soil, we applied stockpiled dairy manure (42 Mg ha dry wt) and hardwood-derived biochar (22.4 Mg ha), singly and in combination with manure, along with a control, yielding four treatments. Nitrogen fertilizer was applied when needed (based on preseason soil test N and crop requirements) in all plots and years, with N mineralized from added manure included in this determination. Available soil nutrients (NH-N; NO-N; Olsen P; and diethylenetriaminepentaacetic acid-extractable K, Mg, Na, Cu, Mn, Zn, and Fe), total C (TC), total N (TN), total organic C (TOC), and pH were evaluated annually, and silage corn nutrient concentration, yield, and uptake were measured over two growing seasons. Biochar treatment resulted in a 1.5-fold increase in available soil Mn and a 1.4-fold increase in TC and TOC, whereas manure produced a 1.2- to 1.7-fold increase in available nutrients (except Fe), compared with controls. In 2009 biochar increased corn silage B concentration but produced no yield increase; in 2010 biochar decreased corn silage TN (33%), S (7%) concentrations, and yield (36%) relative to controls. Manure produced a 1.3-fold increase in corn silage Cu, Mn, S, Mg, K, and TN concentrations and yield compared with the control in 2010. The combined biochar-manure effects were not synergistic except in the case of available soil Mn. In these calcareous soils, biochar did not alter pH or availability of P and cations, as is typically observed for acidic soils. If the second year results are representative, they suggest that biochar applications to calcareous soils may lead to reduced N availability, requiring additional soil N inputs to maintain yield targets.

  12. Fate of Compost Nutrients as Affected by Co-Composting of Chicken and Swine Manures

    NASA Astrophysics Data System (ADS)

    Ogunwande, Gbolabo A.; Ogunjimi, Lawrence A. O.; Osunade, James A.

    2014-04-01

    Passive aeration co-composting using four mixtures of chicken manure and swine manure at 1:0, 1:1, 3:7 and 0:1 with sawdust and rice husk was carried out to study the effects of co-composting on the physicochemical properties of the organic materials. The experiment, which lasted 66 days, was carried out in bins equipped with inverted T aeration pipes. The results showed that nutrient losses decreased as the proportion of chicken manure in the mixtures decreased for saw dust and rice husk treatments. This indicates better nutrientst conservation during composting in swine than chicken manure. Manure mixtures with rice husk had higher pile temperatures (> 55°C), total carbon and total nitrogen losses, while manure mixtures with saw dust had higher total phosphorus loss and carbon to nitrogen ratio. Composts with rice husk demonstrated the ability to reach maturity faster by the rate of drop of the carbon to nitrogen ratio.

  13. Refining in silico simulation to study digestion parameters affecting the bioaccessibility of lipophilic nutrients and micronutrients.

    PubMed

    Marze, Sébastien

    2015-01-01

    Despite the considerable number of in vivo and in vitro studies on the digestive fate of lipophilic nutrients, micronutrients, and bioactives, the effects of the structure and composition of foods on the physicochemical mechanisms of luminal digestion are still poorly understood. Studying them is indeed complex because the number of parameters is high and many of them are interdependent. To solve this problem, an in silico simulation based on a multi-agent system was recently proposed to study the intestinal bioaccessibility of lipophilic nutrients and micronutrients from a single oil droplet. The roles of lipolysis and solubilization in bile salt were included. The effects of several food and digestion parameters were in line with those reported in the experimental literature. The goal of the research reported in this new article was to include more digestion parameters in the simulation in order to make it more realistic against complex cases. This was done in one specific digestion condition reflecting in vitro experiments, using droplets of tricaprylin or triolein containing vitamin A. The structure and principles of the original model were kept, with independent local modifications in order to study each factor separately. First, a gastric step was added where lipolysis took place, and only a marginal effect on the following intestinal step was found. Then, the chemical form of vitamin A, either non-hydrolyzed retinyl ester or retinyl ester instantly hydrolyzed into retinol, was investigated by considering different localizations in the droplet, resulting in a higher bioaccessibility for the retinol. The case of a mixture of tricaprylin and triolein indicated an influence of the oil phase viscosity. The consideration of mixed micelles compared to simple bile salt micelles was also investigated, and resulted in a higher vitamin A bioaccessibility, especially with triolein. Finally, a full model including the most influential parameters was tested to simulate

  14. Nutrient availability affects pigment production but not growth in lichens of biological soil crusts

    USGS Publications Warehouse

    Bowker, M.A.; Koch, G.W.; Belnap, J.; Johnson, N.C.

    2008-01-01

    Recent research suggests that micronutrients such as Mn may limit growth of slow-growing biological soil crusts (BSCs) in some of the drylands of the world. These soil surface communities contribute strongly to arid ecosystem function and are easily degraded, creating a need for new restoration tools. The possibility that Mn fertilization could be used as a restoration tool for BSCs has not been tested previously. We used microcosms in a controlled greenhouse setting to investigate the hypothesis that Mn may limit photosynthesis and consequently growth in Collema tenax, a dominant N-fixing lichen found in BSCs worldwide. We found no evidence to support our hypothesis; furthermore, addition of other nutrients (primarily P, K, and Zn) had a suppressive effect on gross photosynthesis (P = 0.05). We also monitored the growth and physiological status of our microcosms and found that other nutrients increased the production of scytonemin, an important sunscreen pigment, but only when not added with Mn (P = 0.01). A structural equation model indicated that this effect was independent of any photosynthesis-related variable. We propose two alternative hypotheses to account for this pattern: (1) Mn suppresses processes needed to produce scytonemin; and (2) Mn is required to suppress scytonemin production at low light, when it is an unnecessary photosynthate sink. Although Mn fertilization does not appear likely to increase photosynthesis or growth of Collema, it could have a role in survivorship during environmentally stressful periods due to modification of scytonemin production. Thus, Mn enrichment should be studied further for its potential to facilitate BSC rehabilitation. ?? 2008 Elsevier Ltd.

  15. Do breakfast skipping and breakfast type affect energy intake, nutrient intake, nutrient adequacy, and diet quality in young adults? NHANES 1999-2002

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to assess the impact of breakfast skipping and type of breakfast consumed on energy/nutrient intake, nutrient adequacy, and diet quality using a cross-sectional design. The setting was The National Health and Nutrition Examination Survey (NHANES), 1999-2002. The sub...

  16. Numerical studies of continuous nutrient delivery for tumour spheroid culture in a microchannel by electrokinetically-induced pressure-driven flow.

    PubMed

    Movahed, Saeid; Li, Dongqing

    2010-12-01

    Continuous nutrient delivery to cells by pressure-driven flow is desirable for cell culture in lab-on-a-chip devices. An innovative method is proposed to generate an induced pressure-driven flow by using an electrokinetically-driven pump in a H-shape microchannel. A three-dimensional numerical model is developed to study the effectiveness of the proposed mechanism. It is shown that the average velocity of the generated pressure-driven flow is linearly dependent on the applied voltage. Considering the culture of a multicellular tumour spheroid (MTS) in such a microfluidic system, numerical simulations based on EMT6/Ro tumour cells is performed to find the effects of the nutrient distribution (oxygen and glucose), bulk velocity and channel size on the cell growth. Using an empirical formula, the growth of the tumour cell is studied. For low nutrient concentrations and low speed flows, it is found that the MTS grows faster in larger channels. It is also shown that, for low nutrient concentrations, a higher bulk liquid velocity provide better environment for MTS to grow. For lower velocities, it is found that the local MTS growth along the flow direction deviates from the average growth.

  17. High levels of inorganic nutrients affect fertilization kinetics, early development and settlement of the scleractinian coral Platygyra acuta

    NASA Astrophysics Data System (ADS)

    Lam, E. K. Y.; Chui, A. P. Y.; Kwok, C. K.; Ip, A. H. P.; Chan, S. W.; Leung, H. N.; Yeung, L. C.; Ang, P. O.

    2015-09-01

    Dose-response experiments were conducted to investigate the effects of ammonia nitrogen (NH3/NH4 +) and orthophosphate (PO4 3-) on four stages of larval development in Platygyra acuta, including fertilization, embryonic development and the survival, motility, and settlement of planula larvae. Fertilization success was reduced significantly under 200 μM NH3/NH4 + or PO4 3-. These high doses of NH3/NH4 + and PO4 - affected egg viability (or sperm viability and polyspermic block simultaneously) and polyspermic block, respectively. These results provide the first evidence to indicate the mechanisms of how inorganic nutrients might affect coral fertilization processes. For embryonic development, NH3/NH4 + at 25-200 μM caused delay in cell division after 2-h exposure and NH3/NH4 + at 100-200 μM resulted in larval death after 72 h. However, no significant differences were observed in the mobility and survivorship of either planula or competent larvae under different levels of NH3/NH4 + or PO4 3-. There was a significant (~30 %) drop in the settlement of competent larvae under the combined effect of 100 μM NH3/NH4 + and PO4 3-. The effects of elevated nutrients appeared to become more significant only on gametes or larvae undergoing active cellular activities at fertilization, early development, and settlement.

  18. Nutrient demand affects ruminal digestion responses to a change in dietary forage concentration.

    PubMed

    Linton, J A Voelker; Allen, M S

    2007-10-01

    Previous research in our laboratory has indicated that the physical filling effects of high-forage diets become increasingly dominant in determining feed intake and milk production as nutrient demand increases. This effect was tested further by using 14 ruminally and duodenally cannulated Holstein cows in a crossover design experiment with a 14-d preliminary period and two 15-d experimental periods. During the preliminary period, 3.5% fat-corrected milk yield was 15 to 60 kg/d (mean = 40 kg/d), and preliminary voluntary dry matter intake (pVDMI) was 20.6 to 30.5 kg/d (mean = 25.0 kg/ d). Treatments were a low-forage diet (LF), containing 20% (dry matter basis) forage neutral detergent fiber (NDF), and a high-forage diet (HF), containing 27% forage NDF. The ability of linear and quadratic factors of pVDMI to predict the difference in responses of individual cows to treatments (Y(LF) - Y(HF)) was tested by ANOVA, with treatment sequence as a covariate. In contrast to results of previous research, differences in dry matter intake and fat-corrected milk yield responses to LF and HF did not depend on pVDMI. This might be because of the combined physical fill and metabolic satiety effects of LF, especially in cows with the greatest pVDMI. Digestion or passage of NDF might have been inhibited on LF among high-pVDMI cows. As pVDMI increased, NDF turnover time increased more on LF than on HF. Among high-pVDMI cows, the NDF turnover time was unexpectedly greater on LF than on HF. With increasing pVDMI, the digestion rate of potentially digestible NDF decreased at a similar rate on both diets. Passage rates of potentially digestible NDF and indigestible NDF were not related to pVDMI, regardless of treatment. Greater starch fermentation (resulting from greater starch intake) for LF as pVDMI increased likely inhibited NDF digestion through pH-dependent and pH-independent effects. Inhibition of NDF digestion might cause LF and HF to have similar effects on dry matter intake

  19. Uptake of Pharmaceuticals Influences Plant Development and Affects Nutrient and Hormone Homeostases.

    PubMed

    Carter, Laura J; Williams, Mike; Böttcher, Christine; Kookana, Rai S

    2015-10-20

    The detection of a range of active pharmaceutical ingredients (APIs) in the soil environment has led to a number of publications demonstrating uptake by crops, however very few studies have explored the potential for impacts on plant development as a result of API uptake. This study investigated the effect of carbamazepine and verapamil (0.005-10 mg/kg) on a range of plant responses in zucchini (Cucurbita pepo). Uptake increased in a dose-dependent manner, with maximum leaf concentrations of 821.9 and 2.2 mg/kg for carbamazepine and verapamil, respectively. Increased carbamazepine uptake by zucchini resulted in a decrease in above (<60%) and below (<30%) ground biomass compared to the controls (p < 0.05). At soil concentrations >4 mg/kg the mature leaves suffered from burnt edges and white spots as well as a reduction in photosynthetic pigments but no such effects were seen for verapamil. For both APIs, further investigations revealed significant differences in the concentrations of selected plant hormones (auxins, cytokinins, abscisic acid and jasmonates), and in the nutrient composition of the leaves in comparison to the controls (p < 0.05). This is some of the first research to demonstrate that the exposure of plants to APIs is likely to cause impacts on plant development with unknown implications.

  20. Factors affecting population of filamentous bacteria in wastewater treatment plants with nutrients removal.

    PubMed

    Miłobędzka, Aleksandra; Witeska, Anna; Muszyński, Adam

    2016-01-01

    Filamentous population in activated sludge and key operational parameters of full-scale municipal wastewater treatment plants (WWTPs) with bulking problems representative for Poland were investigated with quantitative fluorescence in situ hybridization. Statistical analyses revealed few relationships between operational parameters and biovolume of filamentous bacteria. Sludge age was not only positively correlated with abundance of Chloroflexi (parametric correlation and principal component analysis (PCA)), but also differentiated Microthrix population (analysis of variance (ANOVA)). Phylum Chloroflexi and pH presented a negative relation during the study (PCA). ANOVA showed that pH of influent and sludge volume index (SVI) differentiated abundance of types 0803 and 1851 of Chloroflexi and candidate division TM7. SVI increased along with higher abundance of Microthrix (positive parametric and non-parametric correlations and positive relation in PCA). Biovolumes of morphotypes 0803 and 1851 of Chloroflexi were differentiated by organic matter in influent, also by nutrients in the case of Chloroflexi type 1851. Chemical and biological oxygen demands (COD and BOD5, respectively) were negatively correlated with Microthrix. COD also differentiated the abundance of Haliscomenobacter hydrossis. Results of the study can be used to prevent WWTPs from excessive proliferation of filamentous bacteria and operational problems caused by them--bulking and foaming of activated sludge.

  1. Residental factors affecting nutrient intake and nutritional status of female pharmacy students in Bydgoszcz.

    PubMed

    Jaworowska, Agnieszka; Bazylak, Grzegorz

    2007-01-01

    The aim of present study was to estimate nutrient intake as well as nutritional status of female pharmacy students from Bydgoszcz, and to investigate relationship of these factors with type of usual residence place during academic year The 24-hour recall method was used to evaluate dietary intake of 47 subjects. Measured values of height, body mass and four skinfolds thickness were used for calculation of BM, FFM, %FM indices. An analysis of nutritional status of studied population showed lower body mass and BMI in the sub-group of female students residing outside of their family home. In comparison to the female students living without parents percentage of energy provided by total fat (29.9%) was significantly less and percentage of energy from carbohydrate was significantly higher (55.4%) than students who reside with their parents. Elevated intake of phosphorus and retinol accompanied by inadequate intake of riboflavin, calcium, iron and copper was exhibited in both residence-type related sub-groups of investigated female pharmacy students.

  2. Vector competence of Aedes aegypti mosquitoes for filarial nematodes is affected by age and nutrient limitation.

    PubMed

    Ariani, Cristina V; Juneja, Punita; Smith, Sophia; Tinsley, Matthew C; Jiggins, Francis M

    2015-01-01

    Mosquitoes are one of the most important vectors of human disease. The ability of mosquitoes to transmit disease is dependent on the age structure of the population, as mosquitoes must survive long enough for the parasites to complete their development and infect another human. Age could have additional effects due to mortality rates and vector competence changing as mosquitoes senesce, but these are comparatively poorly understood. We have investigated these factors using the mosquito Aedes aegypti and the filarial nematode Brugia malayi. Rather than observing any effects of immune senescence, we found that older mosquitoes were more resistant, but this only occurred if they had previously been maintained on a nutrient-poor diet of fructose. Constant blood feeding reversed this decline in vector competence, meaning that the number of parasites remained relatively unchanged as mosquitoes aged. Old females that had been maintained on fructose also experienced a sharp spike in mortality after an infected blood meal ("refeeding syndrome") and few survived long enough for the parasite to develop. Again, this effect was prevented by frequent blood meals. Our results indicate that old mosquitoes may be inefficient vectors due to low vector competence and high mortality, but that frequent blood meals can prevent these effects of age.

  3. TITER AND PRODUCT AFFECTS THE DISTRIBUTION OF GENE EXPRESSION AFTER INTRAPUTAMINAL CONVECTION-ENHANCED DELIVERY

    PubMed Central

    Emborg, Marina E.; Hurley, Samuel A.; Joers, Valerie; Tromp, Do P.M.; Swanson, Christine R.; Ohshima-Hosoyama, Sachiko; Bondarenko, Viktorya; Cummisford, Kyle; Sonnemans, Marc; Hermening, Stephan; Blits, Bas; Alexander, Andrew L.

    2014-01-01

    Background Efficacy and safety of intracerebral gene therapy for brain disorders, like Parkinson’s disease, depends on appropriate distribution of gene expression. Objectives To assess if the distribution of gene expression is affected by vector titer and protein type. Methods Four adult macaque monkeys seronegative for adeno-associated virus 5 (AAV5) received in the right and left ventral postcommisural putamen 30μl inoculation of a high or low titer suspension of AAV5 encoding glial derived neurotrophic factor (GDNF) or green fluorescent protein (GFP). Inoculations were performed using convection enhanced delivery and intraoperative MRI (IMRI). Results IMRI confirmed targeting and infusion cloud irradiating from the catheter tip into surrounding area. Postmortem analysis six weeks after surgery revealed GFP and GDNF expression ipsilateral to the injection side that had a titer-dependent distribution. GFP and GDNF expression was also observed in fibers in the Substantia Nigra (SN) pars reticulata (pr), demonstrating anterograde transport. Few GFP-positive neurons were present in the SN pars compacta (pc), possibly by direct retrograde transport of the vector. GDNF was present in many SNpc and SNpr neurons. Conclusions After controlling for target and infusate volume, intracerebral distribution of gene product is affected by vector titer and product biology. PMID:24943657

  4. Shade, irrigation, and nutrients affect flavanoid concentration and yield in American Skullcap.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    American skullcap (Scutellaria lateriflora L.) is valued for its sedative properties that are associated with flavonoids. Information on how growing conditions affect flavonoid content is lacking. A 2x2x3 factorial experiment was conducted in a randomized complete block design (r = 4) with a split ...

  5. Biomass production and nutrient removal by Chlorella sp. as affected by sludge liquor concentration.

    PubMed

    Åkerström, Anette M; Mortensen, Leiv M; Rusten, Bjørn; Gislerød, Hans Ragnar

    2014-11-01

    The use of microalgae for biomass production and nutrient removal from the reject water produced in the dewatering process of anaerobically digested sludge, sludge liquor, was investigated. The sludge liquor was characterized by a high content of total suspended solids (1590 mg L(-1)), a high nitrogen concentration (1210 mg L(-1)), and a low phosphorus concentration (28 mg L(-1)). Chlorella sp. was grown in sludge liquor diluted with wastewater treatment plant effluent water to different concentrations (12, 25, 40, 50, 70, and 100%) using batch mode. The environmental conditions were 25 °C, a continuous lightning of 115 μmol m(-2) s(-1), and a CO2 concentration of 3.0%. The highest biomass production (0.42-0.45 g dry weight L(-1) Day(-1)) was achieved at 40-50% sludge liquor, which was comparable to the production of the control culture grown with an artificial fertilizer. The biomass production was 0.12 and 0.26 g dry weight L(-1) Day(-1) at 12% and 100% sludge liquor, respectively. The percentage of nitrogen in the algal biomass increased from 3.6% in 12% sludge liquor and reached a saturation of ∼10% in concentrations with 50% sludge liquor and higher. The phosphorus content in the biomass increased linearly from 0.2 to 1.5% with increasing sludge liquor concentrations. The highest nitrogen removal rates by algal biosynthesis were 33.6-42.6 mg TN L(-1) Day(-1) at 40-70% sludge liquor, while the highest phosphorus removal rates were 3.1-4.1 mg TP L(-1) Day(-1) at 50-100% sludge liquor.

  6. Factors affecting the sorption of cesium in a nutrient-poor boreal bog.

    PubMed

    Lusa, M; Bomberg, M; Virtanen, S; Lempinen, J; Aromaa, H; Knuutinen, J; Lehto, J

    2015-09-01

    (135)Cs is among the most important radionuclides in the long-term safety assessments of spent nuclear fuel, due to its long half-life of 2.3 My and large inventory in spent nuclear fuel. Batch sorption experiments were conducted to evaluate the sorption behavior of radiocesium ((134)Cs) in the surface moss, peat, gyttja, and clay layers of 7-m-deep profiles taken from a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of radiocesium increased as a function of sampling depth. The highest Kd values, with a geometric mean of 3200 L/kg dry weight (DW), were observed in the bottom clay layer and the lowest in the 0.5-1.0 m peat layer (50 L/kg DW). The maximum sorption in all studied layers was observed at a pH between 7 and 9.5. The in situ Kd values of (133)Cs in surface Sphagnum moss, peat and gyttja samples were one order of magnitude higher than the Kd values obtained using the batch method. The highest in situ Kd values (9040 L/kg DW) were recorded for the surface moss layer. The sterilization of fresh surface moss, peat, gyttja and clay samples decreased the sorption of radiocesium by 38%, although the difference was not statistically significant. However, bacteria belonging to the genera Pseudomonas, Paenibacillus, Rhodococcus and Burkholderia isolated from the bog were found to remove radiocesium from the solution under laboratory conditions. The highest biosorption was observed for Paenibacillus sp. V0-1-LW and Pseudomonas sp. PS-0-L isolates. When isolated bacteria were added to sterilized bog samples, the removal of radiocesium from the solution increased by an average of 50% compared to the removal recorded for pure sterilized peat. Our results demonstrate that the sorption of radiocesium in the bog environment is dependent on pH and the type of the bog layer and that common environmental bacteria prevailing in the bog can remove cesium from the solution phase.

  7. Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water table regimes

    NASA Astrophysics Data System (ADS)

    Straková, P.; Niemi, R. M.; Freeman, C.; Peltoniemi, K.; Toberman, H.; Heiskanen, I.; Fritze, H.; Laiho, R.

    2011-09-01

    Peatlands are carbon (C) storage ecosystems sustained by a high water table (WT). High WT creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WT drawdown caused by climate and/or land-use change. Aerobic decomposers are directly affected by WT drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WT drawdown on aerobic decomposer activity in plant litter at two stages of decomposition (incubated in the field for 1 or 2 years). We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen (N), phosphorus (P) and sulphur. Our study sites represented a three-stage chronosequence from pristine to short-term (years) and long-term (decades) WT drawdown conditions under two nutrient regimes (bog and fen). The litter types included reflected the prevalent vegetation: Sphagnum mosses, graminoids, shrubs and trees. Litter type was the main factor shaping microbial activity patterns and explained about 30 % of the variation in enzyme activities and activity allocation. Overall, enzyme activities were higher in vascular plant litters compared to Sphagnum litters, and the allocation of enzyme activities towards C or nutrient acquisition was related to the initial litter quality (chemical composition). Direct effects of WT regime, site nutrient regime and litter decomposition stage (length of incubation period) summed to only about 40 % of the litter type effect. WT regime alone explained about 5 % of the variation in enzyme activities and activity allocation. Generally, enzyme activity increased following the long-term WT drawdown and the activity allocation turned from P and N acquisition towards C

  8. Factors affecting drug and gene delivery: effects of interaction with blood components.

    PubMed

    Opanasopit, Praneet; Nishikawa, Makiya; Hashida, Mitsuru

    2002-01-01

    Targeted drug delivery systems have been used extensively to improve the pharmacological and therapeutic activities of a wide variety of drugs and genes. In this article, we summarize the factors determining the tissue disposition of delivery systems: the physicochemical and biological characteristics of the delivery system and the anatomic and physiological characteristics of the tissues. There are several modes of drug and gene targeting, ranging from passive to active targeting, and each of these can be achieved by optimizing the design of the delivery system to suit a specific aim. After entering the systemic circulation, either by an intravascular injection or through absorption from an administration site, however, a delivery system encounters a variety of blood components, including blood cells and a range of serum proteins. These components are by no means inert as far as interaction with the delivery system is concerned, and they can sometimes markedly effect its tissue disposition. The interaction with blood components is known to occur with particulate delivery systems, such as liposomes, or with cationic charge-mediated delivery systems for genes. In addition to these rather nonspecific ones, interactions via the targeting ligand of the delivery system can occur. We recently found that mannosylated carriers interact with serum mannan binding protein, greatly altering their tissue disposition in a number of ways that depend on the properties of the carriers involved.

  9. Food, nutrients and nutraceuticals affecting the course of inflammatory bowel disease.

    PubMed

    Uranga, José Antonio; López-Miranda, Visitación; Lombó, Felipe; Abalo, Raquel

    2016-08-01

    Inflammatory bowel diseases (ulcerative colitis; Crohn's disease) are debilitating relapsing inflammatory disorders affecting the gastrointestinal tract, with deleterious effect on quality of life, and increasing incidence and prevalence. Mucosal inflammation, due to altered microbiota, increased intestinal permeability and immune system dysfunction underlies the symptoms and may be caused in susceptible individuals by different factors (or a combination of them), including dietary habits and components. In this review we describe the influence of the Western diet, obesity, and different nutraceuticals/functional foods (bioactive peptides, phytochemicals, omega 3-polyunsaturated fatty acids, vitamin D, probiotics and prebiotics) on the course of IBD, and provide some hints that could be useful for nutritional guidance. Hopefully, research will soon offer enough reliable data to slow down the spread of the disease and to make diet a cornerstone in IBD therapy.

  10. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States

    USGS Publications Warehouse

    Rebich, R.A.; Houston, N.A.; Mize, S.V.; Pearson, D.K.; Ging, P.B.; Evan, Hornig C.

    2011-01-01

    SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  11. Soils, slopes and source rocks: Application of a soil chemistry model to nutrient delivery to rift lakes

    NASA Astrophysics Data System (ADS)

    Harris, Nicholas B.; Tucker, Gregory E.

    2015-06-01

    The topographic evolution of rift basins may be critical to the deposition of lacustrine source rocks such as the organic-rich Lower Cretaceous shales of the South Atlantic margin. Soils have been proposed as a key link between topography and source rock deposition by providing nutrients for the algae growth in rift lakes. Decreasing topographic relief from active rift to late rift has several effects on soils: soils become thicker and finer, erosion of dead surface and soil organic matter decreases, and the fractionation of precipitation between runoff and infiltration may favor increased infiltration. This hypothesis is tested by application of CENTURY, a complex box model that simulates transfer of nutrients within soil pools. The model is first applied to a rainforest soil, with several parameters individually varied. Infiltration experiments show that the concentrations of C, N and P in groundwater decrease rapidly as infiltration decreases, whether due to increased slope or to decreased precipitation. Increased erosion of surface plant litter and topsoil results in substantially decreased nutrient concentrations in groundwater. Increased sand content in soil causes an increase in nutrient concentration. We integrate these variables in analyzing topographic swathes from the Rio Grande Rift, comparing the southern part of the rift, where topography is relatively old and reduced, to the northern rift. C and P concentrations in groundwater increase as slope gradient decreases, resulting in substantially larger C and P concentrations in groundwater in the southern rift than the northern rift. Nitrogen concentrations in groundwater depends on whether infiltration varies as a function of slope gradient; in experiments where the fraction of infiltrated precipitation decreased with increasing slope, N concentrations was also substantially higher in the southern rift; but in experiments where that fraction was held constant, N concentrations was lower in the southern

  12. Nutrient utilisation and intestinal fermentation are differentially affected by the consumption of resistant starch varieties and conventional fibres in pigs.

    PubMed

    Rideout, Todd C; Liu, Qiang; Wood, Peter; Fan, Ming Z

    2008-05-01

    This study examined the influence of different resistant starch (RS) varieties and conventional fibres on the efficiency of nutrient utilisation and intestinal fermentation in pigs. Thirty-six pigs (30 kg) were fed poultry meal-based diets supplemented with 10 % granular resistant corn starch (GCS), granular resistant potato starch (GPS), retrograded resistant corn starch (RCS), guar gum (GG) or cellulose for 36 d according to a completely randomised block design. Distal ileal and total tract recoveries were similar (P>0.05) among the RS varieties. Distal ileal starch recovery was higher (P < 0.05) in pigs consuming the RS diets (27-42 %) as compared with the control group (0.64 %). Consumption of GCS reduced (P < 0.05) apparent total tract digestibility and whole-body retention of crude protein in comparison with the control group. Consumption of GPS reduced (P < 0.05) total tract Ca digestibility and whole-body retention of Ca and P compared with the control group. However, consumption of RCS increased (P < 0.05) total tract Ca digestibility compared with the control group. Caecal butyrate concentration was increased (P < 0.05) following consumption of RCS and GG in comparison with the control group. Consumption of all the RS varieties reduced (P < 0.05) caecal indole concentrations compared with the control. Caecal butyrate concentrations were positively correlated (P < 0.05; r 0.63-0.83) with thermal properties among the RS varieties. We conclude that nutrient utilisation and intestinal fermentation are differentially affected by the consumption of different RS varieties and types of fibres. Thermal properties associated with different RS varieties may be useful markers for developing RS varieties with specific functionality.

  13. Varying type of forage, concentration of metabolizable protein, and source of carbohydrate affects nutrient digestibility and production by dairy cows.

    PubMed

    Weiss, W P; St-Pierre, N R; Willett, L B

    2009-11-01

    The effects of forage source, concentration of metabolizable protein (MP), type of carbohydrate, and their interactions on nutrient digestibility and production were evaluated using a central composite treatment design. All diets (dry basis) contained 50% forage that ranged from 25:75 to 75:25 alfalfa silage:corn silage. Rumen-degradable protein comprised 10.7% of the dry matter (DM) in all diets, but undegradable protein ranged from 4.1 to 7.1%, resulting in dietary MP concentrations of 8.8 to 12.0% of the DM. Dietary starch ranged from 22 to 30% of the DM with a concomitant decrease in neutral detergent fiber concentrations. A total of 15 diets were fed to 36 Holstein cows grouped in 6 blocks. Each block consisted of three 21-d periods, and each cow was assigned a unique sequence of 3 diets, resulting in 108 observations. Milk production and composition, feed intake, and digestibility of major nutrients (via total collection of feces and urine) were measured. Few significant interactions between main effects were observed. Starch concentration had only minor effects on digestibility and production. Replacing corn silage with alfalfa decreased digestibility of N but increased digestibility of neutral detergent fiber. Increasing the concentration of MP increased N digestibility. The concentration (Mcal/kg) of dietary digestible energy (DE) increased linearly as starch concentration increased (very small effect) and was affected by a forage by MP interaction. At low MP, high alfalfa reduced DE concentration, but at high MP, increasing alfalfa increased DE concentration. Increasing alfalfa increased DM and DE intakes, which increased yields of energy-corrected milk, protein, and fat. Increasing MP increased yields of energy-corrected milk and protein. The response in milk protein to changes in MP was much less than predicted using the National Research Council (2001) model.

  14. Nutrient delivery to Lake Winnipeg from the Red-Assiniboine River Basin – A binational application of the SPARROW model

    USGS Publications Warehouse

    Benoy, Glenn A; Jenkinson, R. Wayne; Robertson, Dale; Saad, David A.

    2016-01-01

    Excessive phosphorus (TP) and nitrogen (TN) inputs from the Red–Assiniboine River Basin (RARB) have been linked to eutrophication of Lake Winnipeg; therefore, it is important for the management of water resources to understand where and from what sources these nutrients originate. The RARB straddles the Canada–United States border and includes portions of two provinces and three states. This study represents the first binationally focused application of SPAtially Referenced Regressions on Watershed attributes (SPARROW) models to estimate loads and sources of TP and TN by jurisdiction and basin at multiple spatial scales. Major hurdles overcome to develop these models included: (1) harmonization of geospatial data sets, particularly construction of a contiguous stream network; and (2) use of novel calibration steps to accommodate limitations in spatial variability across the model extent and in the number of calibration sites. Using nutrient inputs for a 2002 base year, a RARB TP SPARROW model was calibrated that included inputs from agriculture, forests and wetlands, wastewater treatment plants (WWTPs) and stream channels, and a TN model was calibrated that included inputs from agriculture, WWTPs and atmospheric deposition. At the RARB outlet, downstream from Winnipeg, Manitoba, the majority of the delivered TP and TN came from the Red River Basin (90%), followed by the Upper Assiniboine River and Souris River basins. Agriculture was the single most important TP and TN source for each major basin, province and state. In general, stream channels (historically deposited nutrients and from bank erosion) were the second most important source of TP. Performance metrics for the RARB SPARROW model are similarly robust compared to other, larger US SPARROW models making it a potentially useful tool to address questions of where nutrients originate and their relative contributions to loads delivered to Lake Winnipeg.

  15. The Tip of the Tail Needle Affects the Rate of DNA Delivery by Bacteriophage P22

    PubMed Central

    Leavitt, Justin C.; Gogokhia, Lasha; Gilcrease, Eddie B.; Bhardwaj, Anshul; Cingolani, Gino; Casjens, Sherwood R.

    2013-01-01

    The P22-like bacteriophages have short tails. Their virions bind to their polysaccharide receptors through six trimeric tailspike proteins that surround the tail tip. These short tails also have a trimeric needle protein that extends beyond the tailspikes from the center of the tail tip, in a position that suggests that it should make first contact with the host’s outer membrane during the infection process. The base of the needle serves as a plug that keeps the DNA in the virion, but role of the needle during adsorption and DNA injection is not well understood. Among the P22-like phages are needle types with two completely different C-terminal distal tip domains. In the phage Sf6-type needle, unlike the other P22-type needle, the distal tip folds into a “knob” with a TNF-like fold, similar to the fiber knobs of bacteriophage PRD1 and Adenovirus. The phage HS1 knob is very similar to that of Sf6, and we report here its crystal structure which, like the Sf6 knob, contains three bound L-glutamate molecules. A chimeric P22 phage with a tail needle that contains the HS1 terminal knob efficiently infects the P22 host, Salmonella enterica, suggesting the knob does not confer host specificity. Likewise, mutations that should abrogate the binding of L-glutamate to the needle do not appear to affect virion function, but several different other genetic changes to the tip of the needle slow down potassium release from the host during infection. These findings suggest that the needle plays a role in phage P22 DNA delivery by controlling the kinetics of DNA ejection into the host. PMID:23951045

  16. Nutrient demand interacts with grass maturity to affect milk fat concentration and digestion responses in dairy cows.

    PubMed

    Kammes, K L; Allen, M S

    2012-09-01

    Effects of grass maturity on dry matter intake (DMI), milk production, ruminal fermentation and pool sizes, digestion and passage kinetics, and chewing activity and the relationship of these effects with preliminary DMI (pDMI) were evaluated using 13 ruminally and duodenally cannulated Holstein cows in a crossover design with a 14-d preliminary period and two 18-d treatment periods. During the preliminary period, pDMI of individual cows ranged from 23.5 to 28.2 kg/d (mean=26.1 kg/d) and 3.5% fat-corrected milk (FCM) yield ranged from 30.8 to 57.2 kg/d (mean=43.7 kg/d). Experimental treatments were diets containing orchardgrass silage harvested either (1) early-cut, less mature (EC) or (2) late-cut, more mature (LC) as the sole forage. Early- and late-cut orchardgrass contained 44.9 and 54.4% neutral detergent fiber (NDF) and 20.1 and 15.3% crude protein, respectively. Forage:concentrate ratio was 58:42 and 46:54 for EC and LC, respectively; both diets contained approximately 25% forage NDF and 30% total NDF. Preliminary DMI, an index of nutrient demand, was determined during the last 4d of the preliminary period when cows were fed a common diet and used as a covariate. Main effects of grass maturity and their interaction with pDMI were tested by ANOVA. The EC diet decreased milk yield and increased milk fat concentration compared with the LC diet. Grass maturity and its interaction with pDMI did not affect FCM yield, DMI, rumen pH, or microbial efficiency. The EC diet increased rates of ruminal digestion of potentially digestible NDF and passage of indigestible NDF (iNDF) compared with the LC diet. The lower concentration and faster passage rate of iNDF for EC resulted in lower rumen pools of iNDF, total NDF, organic matter, and dry matter for EC than LC. Ruminal passage rates of potentially digestible NDF and starch were related to level of intake (quadratic and linear interactions, respectively) and subsequently affected ruminal digestibility of these nutrients

  17. Feed delivery method affects the learning of feeding and competitive behavior in dairy heifers.

    PubMed

    Greter, A M; Leslie, K E; Mason, G J; McBride, B W; DeVries, T J

    2010-08-01

    The objective of this study was to determine how different feeding methods may affect the learning of feeding, sorting, and competitive behavior of growing dairy heifers. We hypothesized that heifers previously fed a total mixed ration (TMR) would distribute their feeding time more evenly throughout the day, sort the new ration less, compete less for feed, maintain a more solid fecal consistency, and continue to grow rapidly compared with heifers previously fed a top-dressed ration (TDR). Thirty-two Holstein heifers (237.2+/-21.9 d of age) were divided into 8 groups of 4 and exposed to 1 of 2 treatments for 13 wk: 1) TMR or 2) TDR, with each containing 65% grass/alfalfa haylage and 35% textured concentrate on a dry matter (DM) basis. Following this feeding period, all heifers were switched to an unfamiliar TMR containing 56.1% grass/alfalfa haylage, 21.0% corn silage, 21.0% high-moisture corn, and 1.9% mineral supplement (DM basis) for 7 wk. Group DM intakes were recorded daily throughout the experiment. Feeding behavior, recorded using time-lapse video, and sorting behavior were measured for 7 d during wk 1, 4, and 7 after the dietary change. Feeding competition was measured on d 2, 4, and 6 of each recording week. Sorting activity was determined through particle size analysis of the fresh feed and orts. The particle size separator separated feed into 4 fractions (long, medium, short, and fine). Sorting of each fraction was calculated as actual intake expressed as a percentage of predicted intake. Animals were scored for fecal consistency twice weekly, using a scale from 1 (liquid) to 4 (solid). Heifers were weighed every 2 wk. Neither DM intake (9.0 kg/d) nor average daily gain (1.2 kg/d) differed between treatments. Sorting also did not differ between treatments. Heifers tended to spend more time feeding if they had previously been fed a TDR (198.8 vs. 186.8 min/d). As they had done before the dietary change, heifers previously fed the TDR spent more time at the

  18. Status of porous tube plant growth unit research - Development of a plant nutrient delivery system for space

    NASA Technical Reports Server (NTRS)

    Dreschel, T. W.; Wheeler, R. M.; Sager, J. C.

    1988-01-01

    A system developed for plant production in space was used to grow wheat, beans, rice, and white potatoes. It was found that the negative gauge pressure used to control the nutrient solution at the root/membrane interface and the pore size influence plant production. The results suggest that wheat, rice, beans, and lettuce can probably be grown with production values resembling those of plants grown in other media. Potato growth seemed to be stunted; this could be a possible response to root restriction.

  19. Dietary potassium diformate did not affect growth and survival but did reduce nutrient digestibility of Pacific white shrimp cultured under clean water conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effect of a dietary supplement potassium diformate (PDF) on growth performance, survival and nutrient digestibility of Pacific white shrimp cultured under clean water conditions. We found that weight gain was not significantly (P>0.05) affected by the different levels of ...

  20. Variation in nutrients formulated and nutrients supplied on 5 California dairies.

    PubMed

    Rossow, H A; Aly, S S

    2013-01-01

    Computer models used in ration formulation assume that nutrients supplied by a ration formulation are the same as the nutrients presented in front of the cow in the final ration. Deviations in nutrients due to feed management effects such as dry matter changes (i.e., rain), loading, mixing, and delivery errors are assumed to not affect delivery of nutrients to the cow and her resulting milk production. To estimate how feed management affects nutrients supplied to the cow and milk production, and determine if nutrients can serve as indexes of feed management practices, weekly total mixed ration samples were collected and analyzed for 4 pens (close-up cows, fresh cows, high-milk-producing, and low-milk-producing cows, if available) for 7 to 12 wk on 5 commercial California dairies. Differences among nutrient analyses from these samples and nutrients from the formulated rations were analyzed by PROC MIXED of SAS (SAS Institute Inc., Cary, NC). Milk fat and milk protein percentages did not vary as much [coefficient of variation (CV) = 18 to 33%] as milk yield (kg; CV = 16 to 47 %) across all dairies and pens. Variability in nutrients delivered were highest for macronutrient fat (CV = 22%), lignin (CV = 15%), and ash (CV = 11%) percentages and micronutrients Fe (mg/kg; CV = 48%), Na (%; CV = 42%), and Zn (mg/kg; CV = 38%) for the milking pens across all dairies. Partitioning of the variability in random effects of nutrients delivered and intraclass correlation coefficients showed that variability in lignin percentage of TMR had the highest correlation with variability in milk yield and milk fat percentage, followed by fat and crude protein percentages. But, variability in ash, fat, and lignin percentages of total mixed ration had the highest correlation with variability in milk protein percentage. Therefore, lignin, fat, and ash may be the best indices of feed management to include effects of variability in nutrients on variability in milk yield, milk fat, and milk

  1. Nutritional plane and selenium supply during gestation affect yield and nutrient composition of colostrum and milk in primiparous ewes.

    PubMed

    Meyer, A M; Reed, J J; Neville, T L; Thorson, J F; Maddock-Carlin, K R; Taylor, J B; Reynolds, L P; Redmer, D A; Luther, J S; Hammer, C J; Vonnahme, K A; Caton, J S

    2011-05-01

    cell count and total somatic cells were greater (P ≤ 0.05) in milk from CON than RES. A cubic effect of day (P ≥ 0.01) was observed for milk yield (g and mL). Butterfat, solids-not-fat, lactose, milk urea N, and Se concentration responded quadratically (P ≤ 0.01) to day. Protein (%), total butterfat, and total Se, and somatic cells (cells/mL and cells/d) decreased linearly (P < 0.01) with day. Results indicate that gestational nutrition affects colostrum and milk yield and nutrient content, even when lactational nutrient requirements are met.

  2. Double Shell Tanks (DST) and Waste Feed Delivery Project Management Quality Affecting Procedures Management Plan

    SciTech Connect

    LUND, D.P.

    2000-09-25

    The purpose of the Double Shell Tanks (DST) and Waste Feed Delivery (WFD) Management Assessment Plan is to define how management assessments within DST h WFD will be conducted. The plan as written currently includes only WFD Project assessment topics. Other DST and WFD group assessment topics will be added in future revisions.

  3. Growth, allocation and tissue chemistry of Picea abies seedlings affected by nutrient supply during the second growing season.

    PubMed

    Kaakinen, Seija; Jolkkonen, Annika; Iivonen, Sari; Vapaavuori, Elina

    2004-06-01

    One-year-old Norway spruce (Picea abies (L.) Karst.) seedlings were grown hydroponically in a growth chamber to investigate the effects of low and high nutrient availability (LN; 0.25 mM N and HN; 2.50 mM N) on growth, biomass allocation and chemical composition of needles, stem and roots during the second growing season. Climatic conditions in the growth chamber simulated the mean growing season from May to early October in Flakaliden, northern Sweden. In the latter half of the growing season, biomass allocation changed in response to nutrient availability: increased root growth and decreased shoot growth led to higher root/shoot ratios in LN seedlings than in HN seedlings. At high nutrient availability, total biomass, especially stem biomass, increased, as did total nonstructural carbohydrate and nitrogen contents per seedling. Responses of stem chemistry to nutrient addition differed from those of adult trees of the same provenance. In HN seedlings, concentrations of alpha-cellulose, hemicellulose and lignin decreased in the secondary xylem. Our results illustrate the significance of retranslocation of stored nutrients to support new growth early in the season when root growth and nutrient uptake are still low. We conclude that nutrient availability alters allocation patterns, thereby influencing the success of 2-year-old Norway spruce seedlings at forest planting sites.

  4. Nutrient demand interacts with grass particle length to affect digestion responses and chewing activity in dairy cows.

    PubMed

    Kammes, K L; Allen, M S

    2012-02-01

    Effects of grass particle length on dry matter intake (DMI), milk production, ruminal fermentation and pool sizes, digestion and passage kinetics, and chewing activity and the relationship of these effects with preliminary DMI (pDMI) were evaluated using 15 ruminally and duodenally cannulated Holstein cows in a crossover design with a 14-d preliminary period and two 18-d treatment periods. During the preliminary period, pDMI of individual cows ranged from 22.6 to 29.8 kg/d (mean=25.8 kg/d) and 3.5% fat-corrected milk yield ranged from 29.2 to 56.9 kg/d (mean=41.9 kg/d). Experimental treatments were diets containing orchardgrass silage chopped to either (a) 19-mm (long) or (b) 10-mm (short) theoretical length of cut as the sole forage. Grass silages contained approximately 46% neutral detergent fiber (NDF); diets contained 50% forage, 23% forage NDF, and 28% total NDF. Preliminary DMI, an index of nutrient demand, was determined during the last 4 d of the preliminary period when cows were fed a common diet and used as a covariate. Main effects of grass particle length and their interaction with pDMI were tested by ANOVA. Grass particle length and its interaction with pDMI did not affect milk yield, milk composition, or rumen pH. Long particle length tended to decrease DMI compared with short particle length, which might have been limited by rumen fill or chewing time, or both. Passage rates of feed fractions did not differ between long and short particle lengths and were not related to level of intake. As pDMI increased, long particles decreased ruminal digestion rate of potentially digestible NDF at a faster rate than short particles. As a result, long particles decreased or tended to decrease rates of ruminal turnover for NDF, organic matter, and dry matter and increased their rumen pools compared with short particles for cows with high pDMI. Long particles increased eating time, which affected cows with high intake to the greatest extent, and total chewing time

  5. Predicting the delivery of sediment and associated nutrients from post-fire debris flows in small upland catchments

    NASA Astrophysics Data System (ADS)

    Nyman, Petter; Sheridan, Gary; Smith, Hugh; Lane, Patrick

    2014-05-01

    Post-fire debris flows are extreme erosion events that can dominate the long term supply of sediment from headwaters to streams in upland catchments. Predicting the location, frequency and magnitude of debris flows is therefore important for understanding sediment dynamics in upland catchments and providing a basis on which to manage hydro-geomorphic risk in burned areas. In this study we survey 10 post-fire debris flow events in southeast Australia with aims to i) identify rainfall conditions underlying the debris flow response, ii) quantify erosion rates in hillslope and channel source areas, and iii) estimate the delivery of sediment and water quality constituents to receiving waterways. Rainfall events that triggered debris flows had an annual exceedance probability ranging from 0.1 to 0.6, and 30-minute intensities, I30, ranging from 17-60 mm h-1. Sediment delivery by debris flows (100-200 t ha-1) is similar to that which has been reported for similar events in the western US and Spain. In terms of eroded volume, there was on average an equal contribution from hillslopes and channels to debris flows, which is in agreement with the calculations of surface and subsurface source contributions obtained from radionuclide concentrations. In terms of the potential water quality impacts from post-fire debris flows, the hillslopes had much higher concentration of constituents such as fine clay and silt, plant available phosphorous and total carbon. The data on debris flow magnitude was used to evaluate two different approaches for predicting sediment delivery from debris flows. A statistical debris flow model developed by the US Geological Surveys and parameterized for catchments in western US performed well (R2 = 0.92) in terms of predicting the overall volume of material delivered at the catchment outlet. An alternative modeling approach, using local slope and contributing area as predictors of erosion, also produced good results, and could be used to obtain more

  6. Stimulation of nitrogen turnover due to nutrients release from aggregates affected by freeze-thaw in wetland soils

    NASA Astrophysics Data System (ADS)

    Song, Yang; Zou, Yuanchun; Wang, Guoping; Yu, Xiaofei

    2017-02-01

    The freeze-thaw phenomenon will occur more frequently in mid-high latitude ecosystems under climate change which has a remarkable effect on biogeochemical processes in wetland soils. Here, we used a wet sieving procedure and a barometric process separation (BaPS) technique to examine the responses of wetland soil aggregates and related carbon and nitrogen turnover affected by the freeze-thaw treatment. Wetland soil samples were divided into a treatment group and a control group. The treatment group was incubated at temperatures fluctuating from 10 °C to -10 °C, whereas the control group was incubated at the constant temperature of 10 °C. A 24 h process was set as the total freeze-thaw cycle, and the experiment had 20 continuous freeze-thaw cycles. In our results, the freeze-thaw process caused great destruction to the >2 mm water-stable aggregates (WSA) fraction and increased the <0.053 mm WSA fraction. The dissolved organic carbon (DOC) content was stimulated during the initial freeze-thaw cycles followed by a rapid decline, and then still increased during subsequent freeze-thaw cycles, which was mainly determined by the soil organic carbon (SOC). The NH4+ and NO3- content, respiration rate and gross nitrification rate were all significantly improved by the freeze-thaw effect. Because the amount of NH4+ and NO3- expressed prominent negative responses to the content of >2 mm WSA fraction and the gross nitrification rate can be stimulated at the initial freeze-thaw cycles, nutrients and substrates may play a leading role in the freeze-thaw treatment regardless of the minimal influences on microbial biomass pools.

  7. Identity of the Growth-Limiting Nutrient Strongly Affects Storage Carbohydrate Accumulation in Anaerobic Chemostat Cultures of Saccharomyces cerevisiae▿ † ‡

    PubMed Central

    Hazelwood, Lucie A.; Walsh, Michael C.; Luttik, Marijke A. H.; Daran-Lapujade, Pascale; Pronk, Jack T.; Daran, Jean-Marc

    2009-01-01

    Accumulation of glycogen and trehalose in nutrient-limited cultures of Saccharomyces cerevisiae is negatively correlated with the specific growth rate. Additionally, glucose-excess conditions (i.e., growth limitation by nutrients other than glucose) are often implicated in high-level accumulation of these storage carbohydrates. The present study investigates how the identity of the growth-limiting nutrient affects accumulation of storage carbohydrates in cultures grown at a fixed specific growth rate. In anaerobic chemostat cultures (dilution rate, 0.10 h−1) of S. cerevisiae, the identity of the growth-limiting nutrient (glucose, ammonia, sulfate, phosphate, or zinc) strongly affected storage carbohydrate accumulation. The glycogen contents of the biomass from glucose- and ammonia-limited cultures were 10- to 14-fold higher than those of the biomass from cultures grown under the other three glucose-excess regimens. Trehalose levels were specifically higher under nitrogen-limited conditions. These results demonstrate that storage carbohydrate accumulation in nutrient-limited cultures of S. cerevisiae is not a generic response to excess glucose but instead is strongly dependent on the identity of the growth-limiting nutrient. While transcriptome analysis of wild-type and msn2Δ msn4Δ strains confirmed that transcriptional upregulation of glycogen and trehalose biosynthesis genes is mediated by Msn2p/Msn4p, transcriptional regulation could not quantitatively account for the drastic changes in storage carbohydrate accumulation. The results of assays of glycogen synthase and glycogen phosphorylase activities supported involvement of posttranscriptional regulation. Consistent with the high glycogen levels in ammonia-limited cultures, the ratio of glycogen synthase to glycogen phosphorylase in these cultures was up to eightfold higher than the ratio in the other glucose-excess cultures. PMID:19734328

  8. Growth of mature boreal Norway spruce was not affected by elevated [CO(2)] and/or air temperature unless nutrient availability was improved.

    PubMed

    Sigurdsson, Bjarni D; Medhurst, Jane L; Wallin, Göran; Eggertsson, Olafur; Linder, Sune

    2013-11-01

    The growth responses of mature Norway spruce (Picea abies (L.) Karst.) trees exposed to elevated [CO(2)] (CE; 670-700 ppm) and long-term optimized nutrient availability or elevated air temperature (TE; ±3.9 °C) were studied in situ in northern Sweden in two 3 year field experiments using 12 whole-tree chambers in ca. 40-year-old forest. The first experiment (Exp. I) studied the interactions between CE and nutrient availability and the second (Exp. II) between CE and TE. It should be noted that only air temperature was elevated in Exp. II, while soil temperature was maintained close to ambient. In Exp. I, CE significantly increased the mean annual height increment, stem volume and biomass increment during the treatment period (25, 28, and 22%, respectively) when nutrients were supplied. There was, however, no significant positive CE effect found at the low natural nutrient availability. In Exp. II, which was conducted at the natural site fertility, neither CE nor TE significantly affected height or stem increment. It is concluded that the low nutrient availability (mainly nitrogen) in the boreal forests is likely to restrict their response to the continuous rise in [CO(2)] and/or TE.

  9. Factors Affecting Spatial and Temporal Variability in Nutrient and Pesticide Concentrations in the Surficial Aquifer on the Delmarva Peninsula

    USGS Publications Warehouse

    Debrewer, Linda M.; Ator, Scott W.; Denver, Judith M.

    2007-01-01

    Water quality in the unconfined, unconsolidated surficial aquifer on the Delmarva Peninsula is influenced by the availability of soluble ions from natural and human sources, and by geochemical factors that affect the mobility and fate of these ions within the aquifer. Ground-water samples were collected from 60 wells completed in the surficial aquifer of the peninsula in 2001 and analyzed for major ions, nutrients, and selected pesticides and degradation products. Analytical results were compared to similar data from a subset of sampled wells in 1988, as well as to land use, soils, geology, depth, and other potential explanatory variables to demonstrate the effects of natural and human factors on water quality in the unconfined surficial aquifer. This study was conducted as part of the National Water-Quality Assessment Program of the U.S. Geological Survey, which is designed (in part) to describe the status and trends in ground-water quality and to provide an understanding of natural and human factors that affect ground-water chemistry in different parts of the United States. Results of this study may be useful for water-resources managers tasked with addressing water-quality issues of local and regional importance because the surficial aquifer on the Delmarva Peninsula is a major source of water for domestic and public supply and provides the majority of flow in local streams. Human impacts are apparent in ground-water quality throughout the surficial aquifer. The surficial aquifer on the Delmarva Peninsula is generally sandy and very permeable with well-oxygenated ground water. Dissolved constituents found throughout various depths of the unconfined aquifer are likely derived from the predominantly agricultural practices on the peninsula, although effects of road salt, mineral dissolution, and other natural and human influences are also apparent in some areas. Nitrate occurred at concentrations exceeding natural levels in many areas, and commonly exceeded 10

  10. Sediment and nutrient delivery from thermokarst features in the foothills of the North Slope, Alaska: Potential impacts on headwater stream ecosystems

    USGS Publications Warehouse

    Bowden, W.B.; Gooseff, M.N.; Balser, A.; Green, A.; Peterson, B.J.; Bradford, J.

    2008-01-01

    Permafrost is a defining characteristic of the Arctic environment. However, climate warming is thawing permafrost in many areas leading to failures in soil structure called thermokarst. An extensive survey of a 600 km2 area in and around the Toolik Lake Natural Research Area (TLNRA) revealed at least 34 thermokarst features, two thirds of which were new since ???1980 when a high resolution aerial survey of the area was done. Most of these thermokarst features were associated with headwater streams or lakes. We have measured significantly increased sediment and nutrient loading from thermokarst features to streams in two well-studied locations near the TLNRA. One small thermokarst gully that formed in 2003 on the Toolik River in a 0.9 km2 subcatchment delivered more sediment to the river than is normally delivered in 18 years from 132 km2 in the adjacent upper Kuparuk River basin (a long-term monitoring reference site). Ammonium, nitrate, and phosphate concentrations downstream from a thermokarst feature on Imnavait Creek increased significantly compared to upstream reference concentrations and the increased concentrations persisted over the period of sampling (1999-2005). The downstream concentrations were similar to those we have used in a long-term experimental manipulation of the Kuparuk River and that have significantly altered the structure and function of that river. A subsampling of other thermokarst features from the extensive regional survey showed that concentrations of ammonium, nitrate, and phosphate were always higher downstream of the thermokarst features. Our previous research has shown that even minor increases in nutrient loading stimulate primary and secondary production. However, increased sediment loading could interfere with benthic communities and change the responses to increased nutrient delivery. Although the terrestrial area impacted by thermokarsts is limited, the aquatic habitat altered by these failures can be extensive. If warming in

  11. The effects of weed-crop competition on nutrient uptake as affected by crop rotation and fertilizers.

    PubMed

    Mohammaddoust-E-Chamanabad, Hamid Reza; Asghari, Ali; Tulikov, Aleksander Mikhailovic

    2007-11-15

    A field study at the Agricultural University of Timiriazev, Moscow, was conducted to determine the effect of crop rotation and Long-term fertilizer application on differences in the competitive ability of spring barley and weeds to nutrient uptake in 2004 and 2005. Spring barley was cultivated in continuous and in crop rotation with winter rye, potato, clover, flax and fallow, with and without NPK application since 1912. Spring barley, especially in no fertilizer plots grown in crop rotation has greater dry mass than spring barley grown in continuous. While dry weed mass markedly decreased in crop rotation. Decrease dry weeds mass was greater when NPK had applied. The statistical analyses show that when spring barley grew in competition with weeds in the no fertilizer plots, crop rotation significantly increased nutrient content in spring barley, but when fertilizer applied the content of N, P2O5 and K2O in barley did not change. Lowest weeds nutrient content observed where soil fertility was increased by crop rotation and NPK application. Crop rotation significantly increased total nutrient uptake of soils by spring barley, but decreased total nutrient uptake by weeds.

  12. Interorganizational factors affecting the delivery of primary care to older Americans.

    PubMed Central

    Kaluzny, A D; Zuckerman, H S; Rabiner, D J

    1998-01-01

    OBJECTIVE: To discuss different types and forms of interorganizational linkages involved in the provision of primary care to older Americans, along with their distinguishing characteristics. RESEARCH STRATEGY: To take advantage of these linkage characteristics. The strategy requires a partnership with health services organizations and providers actually involved in the provision of services along with a planned sequence of activities involving hypotheses and methods development, intervention trials, and finally, demonstration and implementation. CONCLUSION: Because older Americans are frequent users of health services, their need for continuity and access provides an opportunity to examine changes to the delivery system and to monitor the system's capability for meeting their healthcare needs. PMID:9618676

  13. Comparison of two methods for estimating discharge and nutrient loads from Tidally affected reaches of the Myakka and Peace Rivers, West-Central Florida

    USGS Publications Warehouse

    Levesque, V.A.; Hammett, K.M.

    1997-01-01

    The Myakka and Peace River Basins constitute more than 60 percent of the total inflow area and contribute more than half the total tributary inflow to the Charlotte Harbor estuarine system. Water discharge and nutrient enrichment have been identified as significant concerns in the estuary, and consequently, it is important to accurately estimate the magnitude of discharges and nutrient loads transported by inflows from both rivers. Two methods for estimating discharge and nutrient loads from tidally affected reaches of the Myakka and Peace Rivers were compared. The first method was a tidal-estimation method, in which discharge and nutrient loads were estimated based on stage, water-velocity, discharge, and water-quality data collected near the mouths of the rivers. The second method was a traditional basin-ratio method in which discharge and nutrient loads at the mouths were estimated from discharge and loads measured at upstream stations. Stage and water-velocity data were collected near the river mouths by submersible instruments, deployed in situ, and discharge measurements were made with an acoustic Doppler current profiler. The data collected near the mouths of the Myakka River and Peace River were filtered, using a low-pass filter, to remove daily mixed-tide effects with periods less than about 2 days. The filtered data from near the river mouths were used to calculate daily mean discharge and nutrient loads. These tidal-estimation-method values were then compared to the basin-ratio-method values. Four separate 30-day periods of differing streamflow conditions were chosen for monitoring and comparison. Discharge and nutrient load estimates computed from the tidal-estimation and basin-ratio methods were most similar during high-flow periods. However, during high flow, the values computed from the tidal-estimation method for the Myakka and Peace Rivers were consistently lower than the values computed from the basin-ratio method. There were substantial

  14. Administration routes affect the quality of immune responses: A cross-sectional evaluation of particulate antigen-delivery systems.

    PubMed

    Mohanan, Deepa; Slütter, Bram; Henriksen-Lacey, Malou; Jiskoot, Wim; Bouwstra, Joke A; Perrie, Yvonne; Kündig, Thomas M; Gander, Bruno; Johansen, Pål

    2010-11-01

    Particulate delivery systems such as liposomes and polymeric nano- and microparticles are attracting great interest for developing new vaccines. Materials and formulation properties essential for this purpose have been extensively studied, but relatively little is known about the influence of the administration route of such delivery systems on the type and strength of immune response elicited. Thus, the present study aimed at elucidating the influence on the immune response when of immunising mice by different routes, such as the subcutaneous, intradermal, intramuscular, and intralymphatic routes with ovalbumin-loaded liposomes, N-trimethyl chitosan (TMC) nanoparticles, and poly(lactide-co-glycolide) (PLGA) microparticles, all with and without specifically selected immune-response modifiers. The results showed that the route of administration caused only minor differences in inducing an antibody response of the IgG1 subclass, and any such differences were abolished upon booster immunisation with the various adjuvanted and non-adjuvanted delivery systems. In contrast, the administration route strongly affected both the kinetics and magnitude of the IgG2a response. A single intralymphatic administration of all evaluated delivery systems induced a robust IgG2a response, whereas subcutaneous administration failed to elicit a substantial IgG2a response even after boosting, except with the adjuvanted nanoparticles. The intradermal and intramuscular routes generated intermediate IgG2a titers. The benefit of the intralymphatic administration route for eliciting a Th1-type response was confirmed in terms of IFN-gamma production of isolated and re-stimulated splenocytes from animals previously immunised with adjuvanted and non-adjuvanted liposomes as well as with adjuvanted microparticles. Altogether the results show that the IgG2a associated with Th1-type immune responses are sensitive to the route of administration, whereas IgG1 response associated with Th2-type immune

  15. Physical Factors Affecting Plasmid DNA Compaction in Stearylamine-Containing Nanoemulsions Intended for Gene Delivery

    PubMed Central

    Silva, André Leandro; Júnior, Francisco Alexandrino; Verissimo, Lourena Mafra; Agnez-Lima, Lucymara Fassarella; Egito, Lucila Carmem Monte; de Oliveira, Anselmo Gomes; do Egito, Eryvaldo Socrates Tabosa

    2012-01-01

    Cationic lipids have been used in the development of non-viral gene delivery systems as lipoplexes. Stearylamine, a cationic lipid that presents a primary amine group when in solution, is able to compact genetic material by electrostatic interactions. In dispersed systems such as nanoemulsions this lipid anchors on the oil/water interface confering a positive charge to them. The aim of this work was to evaluate factors that influence DNA compaction in cationic nanoemulsions containing stearylamine. The influence of the stearylamine incorporation phase (water or oil), time of complexation, and different incubation temperatures were studied. The complexation rate was assessed by electrophoresis migration on agarose gel 0.7%, and nanoemulsion and lipoplex characterization was done by Dynamic Light Scattering (DLS). The results demonstrate that the best DNA compaction process occurs after 120 min of complexation, at low temperature (4 ± 1 °C), and after incorporation of the cationic lipid into the aqueous phase. Although the zeta potential of lipoplexes was lower than the results found for basic nanoemulsions, the granulometry did not change. Moreover, it was demonstrated that lipoplexes are suitable vehicles for gene delivery. PMID:24281666

  16. Physical factors affecting plasmid DNA compaction in stearylamine-containing nanoemulsions intended for gene delivery.

    PubMed

    Silva, André Leandro; Alexandrino, Francisco; Verissimo, Lourena Mafra; Agnez-Lima, Lucymara Fassarella; Egito, Lucila Carmem Monte; de Oliveira, Anselmo Gomes; do Egito, Eryvaldo Socrates Tabosa

    2012-06-18

    Cationic lipids have been used in the development of non-viral gene delivery systems as lipoplexes. Stearylamine, a cationic lipid that presents a primary amine group when in solution, is able to compact genetic material by electrostatic interactions. In dispersed systems such as nanoemulsions this lipid anchors on the oil/water interface confering a positive charge to them. The aim of this work was to evaluate factors that influence DNA compaction in cationic nanoemulsions containing stearylamine. The influence of the stearylamine incorporation phase (water or oil), time of complexation, and different incubation temperatures were studied. The complexation rate was assessed by electrophoresis migration on agarose gel 0.7%, and nanoemulsion and lipoplex characterization was done by Dynamic Light Scattering (DLS). The results demonstrate that the best DNA compaction process occurs after 120 min of complexation, at low temperature (4 ± 1 °C), and after incorporation of the cationic lipid into the aqueous phase. Although the zeta potential of lipoplexes was lower than the results found for basic nanoemulsions, the granulometry did not change. Moreover, it was demonstrated that lipoplexes are suitable vehicles for gene delivery.

  17. Nutrient demand interacts with legume particle length to affect digestion responses and rumen pool sizes in dairy cows.

    PubMed

    Kammes, K L; Ying, Y; Allen, M S

    2012-05-01

    Effects of legume particle length on dry matter intake (DMI), milk production, ruminal fermentation and pool sizes, and digestion and passage kinetics, and the relationship of these effects with preliminary DMI (pDMI) were evaluated using 13 ruminally and duodenally cannulated Holstein cows in a crossover design with a 14-d preliminary period and two 19-d treatment periods. During the preliminary period, pDMI of individual cows ranged from 22.8 to 32.4 kg/d (mean=26.5 kg/d) and 3.5% fat-corrected milk yield ranged from 22.9 to 62.4 kg/d (mean=35.1 kg/d). Experimental treatments were diets containing alfalfa silage chopped to (1) 19 mm (long cut, LC) or (2) 10 mm (short cut, SC) theoretical length of cut as the sole forage. Alfalfa silages contained approximately 43% neutral detergent fiber (NDF); diets contained approximately 47% forage and 20% forage NDF. Preliminary DMI, an index of nutrient demand, was determined during the last 4 d of the preliminary period, when cows were fed a common diet, and used as a covariate. Main effects of legume particle length and their interaction with pDMI were tested by ANOVA. Alfalfa particle length and its interaction with pDMI did not affect milk yield or rumen pH. The LC diet decreased milk fat concentration more per kilogram of pDMI increase than the SC diet and increased yields of milk fat and fat-corrected milk less per kilogram of pDMI increase than the SC diet, resulting in a greater benefit for LC at low pDMI and for SC at high pDMI. The LC diet tended to decrease DMI compared with the SC diet. Ruminal digestion and passage rates of feed fractions did not differ between LC and SC and were not related to level of intake. The LC diet tended to decrease the rate of ruminal turnover for NDF but increased NDF rumen pools at a slower rate than the SC diet as pDMI increased. This indicated that the faster NDF turnover rate did not counterbalance the higher DMI for SC, resulting in larger NDF rumen pools for SC than LC. As p

  18. Biomass, gas exchange, and nutrient contents in upland rice plants affected by application forms of microorganism growth promoters.

    PubMed

    Nascente, Adriano Stephan; de Filippi, Marta Cristina Corsi; Lanna, Anna Cristina; de Souza, Alan Carlos Alves; da Silva Lobo, Valácia Lemes; da Silva, Gisele Barata

    2017-01-01

    Microorganisms are considered a genetic resource with great potential for achieving sustainable development of agricultural areas. The objective of this research was to determine the effect of microorganism application forms on the production of biomass, gas exchange, and nutrient content in upland rice. The experiment was conducted under greenhouse conditions in a completely randomized design in a factorial 7 × 3 + 1, with four replications. The treatments consisted of combining seven microorganisms with three application forms (microbiolized seed; microbiolized seed + soil drenched with a microorganism suspension at 7 and 15 days after sowing (DAS); and microbiolized seed + plant sprayed with a microorganism suspension at 7 and 15 DAS) and a control (water). Treatments with Serratia sp. (BRM32114), Bacillus sp. (BRM32110 and BRM32109), and Trichoderma asperellum pool provided, on average, the highest photosynthetic rate values and dry matter biomass of rice shoots. Plants treated with Burkolderia sp. (BRM32113), Serratia sp. (BRM32114), and Pseudomonas sp. (BRM32111 and BRM32112) led to the greatest nutrient uptake by rice shoots. Serratia sp. (BRM 32114) was the most effective for promoting an increase in the photosynthetic rate, and for the greatest accumulation of nutrients and dry matter at 84 DAS, in rice shoots, which differed from the control treatment. The use of microorganisms can bring numerous benefits of rice, such as improving physiological characteristics, nutrient uptake, biomass production, and grain yield.

  19. Composting of biochars improves their sorption properties, retains nutrients during composting and affects greenhouse gas emissions after soil application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar application to soils has been suggested to elevate nutrient sorption, improve soil fertility and reduce net greenhouse gas (GHG) emissions. We examined the impact of composting biochar together with a biologically active substrate (i.e., livestock manure-straw mixture). We hypothesized that ...

  20. Thrombocytopenia in pregnancy: do the time of diagnosis and delivery route affect pregnancy outcome in parturients with idiopathic thrombocytopenic purpura?

    PubMed

    Yuce, T; Acar, D; Kalafat, E; Alkilic, A; Cetindag, E; Soylemez, F

    2014-12-01

    The objective of this study was to investigate the determining effects of diagnosis time on pregnancy outcomes in a population of pregnant women with idiopathic thrombocytopenic purpura (ITP). Records of all the pregnant women with thrombocytopenia were evaluated. Those with a confirmed diagnosis of ITP were included in the study. Main outcome measures were antenatal thrombocyte count, postpartum haemorrhage rate, and route of delivery. Foetal outcomes such as foetal thrombocyte count, haemorrhage, and birth weight were also reported as secondary outcome measures. Time of diagnosis either antenatal or preconception did not significantly alter the investigated parameters. Delivery route had no impact on complication rates. Time of diagnosis also did not affect treatment modality. ITP is rare disorder accounting for less than 5 % of all pregnant thrombocytopenias. Time of diagnosis does not affect maternal-foetal outcomes or treatment modality unless diagnosis is made during labour. Compared to gestational thrombocytopenia, treatment rates may differ but treatment modalities remain the same and the effort put into making the differential should be weighed against maternal stress factors for lengthy laboratory evaluation as long as the thrombocytopenia is of pure nature without any systemic involvement.

  1. Increasing Plant Based Foods or Dairy Foods Differentially Affects Nutrient Intakes: Dietary Scenarios Using NHANES 2007–2010

    PubMed Central

    Cifelli, Christopher J.; Houchins, Jenny A.; Demmer, Elieke; Fulgoni, Victor L.

    2016-01-01

    Diets rich in plant foods and lower in animal-based products have garnered increased attention among researchers, dietitians and health professionals in recent years for their potential to, not only improve health, but also to lessen the environmental impact. However, the potential effects of increasing plant-based foods at the expense of animal-based foods on macro- and micronutrient nutrient adequacy in the U.S. diet is unknown. In addition, dairy foods are consistently under consumed, thus the impact of increased dairy on nutrient adequacy is important to measure. Accordingly, the objective of this study was to use national survey data to model three different dietary scenarios to assess the effects of increasing plant-based foods or dairy foods on macronutrient intake and nutrient adequacy. Data from the National Health and Nutrition Examination Survey (NHANES) 2007–2010 for persons two years and older (n = 17,387) were used in all the analyses. Comparisons were made of usual intake of macronutrients and shortfall nutrients of three dietary scenarios that increased intakes by 100%: (i) plant-based foods; (ii) protein-rich plant-based foods (i.e., legumes, nuts, seeds, soy); and (iii) milk, cheese and yogurt. Scenarios (i) and (ii) had commensurate reductions in animal product intake. In both children (2–18 years) and adults (≥19 years), the percent not meeting the Estimated Average Requirement (EAR) decreased for vitamin C, magnesium, vitamin E, folate and iron when plant-based foods were increased. However the percent not meeting the EAR increased for calcium, protein, vitamin A, and vitamin D in this scenario. Doubling protein-rich plant-based foods had no effect on nutrient intake because they were consumed in very low quantities in the baseline diet. The dairy model reduced the percent not meeting the EAR for calcium, vitamin A, vitamin D, magnesium, and protein, while sodium and saturated fat levels increased. Our modeling shows that increasing plant

  2. Increasing Plant Based Foods or Dairy Foods Differentially Affects Nutrient Intakes: Dietary Scenarios Using NHANES 2007-2010.

    PubMed

    Cifelli, Christopher J; Houchins, Jenny A; Demmer, Elieke; Fulgoni, Victor L

    2016-07-11

    Diets rich in plant foods and lower in animal-based products have garnered increased attention among researchers, dietitians and health professionals in recent years for their potential to, not only improve health, but also to lessen the environmental impact. However, the potential effects of increasing plant-based foods at the expense of animal-based foods on macro- and micronutrient nutrient adequacy in the U.S. diet is unknown. In addition, dairy foods are consistently under consumed, thus the impact of increased dairy on nutrient adequacy is important to measure. Accordingly, the objective of this study was to use national survey data to model three different dietary scenarios to assess the effects of increasing plant-based foods or dairy foods on macronutrient intake and nutrient adequacy. Data from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 for persons two years and older (n = 17,387) were used in all the analyses. Comparisons were made of usual intake of macronutrients and shortfall nutrients of three dietary scenarios that increased intakes by 100%: (i) plant-based foods; (ii) protein-rich plant-based foods (i.e., legumes, nuts, seeds, soy); and (iii) milk, cheese and yogurt. Scenarios (i) and (ii) had commensurate reductions in animal product intake. In both children (2-18 years) and adults (≥19 years), the percent not meeting the Estimated Average Requirement (EAR) decreased for vitamin C, magnesium, vitamin E, folate and iron when plant-based foods were increased. However the percent not meeting the EAR increased for calcium, protein, vitamin A, and vitamin D in this scenario. Doubling protein-rich plant-based foods had no effect on nutrient intake because they were consumed in very low quantities in the baseline diet. The dairy model reduced the percent not meeting the EAR for calcium, vitamin A, vitamin D, magnesium, and protein, while sodium and saturated fat levels increased. Our modeling shows that increasing plant

  3. Assessment of Water and Nitrate-N deep percolation fluxes in soil as affected by irrigation and nutrient management practices

    NASA Astrophysics Data System (ADS)

    Tsehaye, Habte; Ceglie, Francesco; Mimiola, Giancarlo; dragonetti, giovanna; Lamaddalena, Nicola; Coppola, Antonio

    2015-04-01

    Many farming practices can result in contamination of groundwater, due to the downward migration of fertilizers and pesticides through the soil profile. The detrimental effects of this contamination are not limited to deterioration of chemical and physical properties of soils and waters, but also constitute a real risk to human and ecosystem health. Groundwater contamination may come from a very large array of chemicals. Nevertheless, on a global scale the main cause of pollution is a high nitrate concentration in the aquifer water. Nitrate concentrations of groundwater have constantly increased during the last decades, and the widespread use of commercial N fertilizers has been implicated as the main causative factor. It is often claimed that nutrient management in organic farming is more environmentally sustainable than its conventional counterpart. It is commonly presumed that organic agriculture causes only minimal environmental pollution. There is scientific evidence that organic management may enhance some soil physical and biological properties. In particular, soil fertility management strategies can affect soil properties and the related hydrological processes. It is thus crucial to quantify and predict management effects on soil properties in order to evaluate the effects of soil type, natural processes such as decomposition of organic matter, irrigation applications and preferential flow on the deep percolation fluxes of water and nitrates to the groundwater. In this study, we measured the water fluxes and the quality of water percolating below the root zone, underlying organic agriculture systems in greenhouse. Specifically, the aim was to examine the effects of application time and type of organic matter in the soil on the nitrate-N deep percolation fluxes under the following three organic soil fertility strategies in greenhouse tomato experiment: i. Organic input Substitution (which will be hereafter denoted SUBST) is represented as typical

  4. Composting of waste paint sludge containing melamine resin as affected by nutrients and gypsum addition and microbial inoculation.

    PubMed

    Tian, Yongqiang; Chen, Liming; Gao, Lihong; Michel, Frederick C; Wan, Caixia; Li, Yebo; Dick, Warren A

    2012-03-01

    Melamine formaldehyde resins have hard and durable properties and are found in many products, including automobile paints. These resins contain high concentrations of nitrogen and, if properly composted, can yield valuable products. We evaluated the effects of starter compost, nutrients, gypsum and microbial inoculation on composting of paint sludge containing melamine resin. A bench-scale composting experiment was conducted at 55 °C for 91 days and then at 30 °C for an additional 56 days. After 91 days, the composts were inoculated with a mixed population of melamine-degrading microorganisms. Melamine resin degradation after the entire 147 days of composting varied between 73 and 95% for the treatments with inoculation of microorganisms compared to 55-74% for the treatments without inoculation. Degradation was also enhanced by nutrients and gypsum additions. Our results infer that large scale composting of melamine resins in paint sludge is possible.

  5. Growth, biomass allocation and nutrient use efficiency in Cladium jamaicense and Typha domingensis as affected by phosphorus and oxygen availability

    USGS Publications Warehouse

    Lorenzen, B.; Brix, H.; Mendelssohn, I.A.; McKee, K.L.; Miao, S.L.

    2001-01-01

    The effects of phosphorus (P) and oxygen availability on growth, biomass allocation and nutrient use efficiency in Cladium jamaicense Crantz and Typha domingensis Pers. were studied in a growth facility equipped with steady-state hydroponic rhizotrons. The treatments included four P concentrations (10, 40, 80 and 500 ??g I-1) and two oxygen concentration (8.0 and <0.5 mg O2 I-1) in the culture solutions. In Cladium, no clear relationship was found between P availability and growth rate (19-37 mg g-1 d-1), the above to below ground biomass ratio (A/B) (mean = 4.6), or nitrogen use efficiency (NUE) (mean = 72 g dry weight g-1 N). However, the ratio between root supported tissue (leaves, rhizomes and ramets) and root biomass (S/R) (5.6-8) increased with P availability. In contrast, the growth rate (48-89 mg g-1 d-1) and the biomass ratios A/B (2.4-6.1) and S/R (5.4-10.3) of Typha increased with P availability, while NUE (71-30 g dry weight g-1 N) decreased. The proportion of root laterals was similar in the two species, but Typha had thinner root laterals (diameter = 186 ??m) than Cladium (diameter = 438 ??m) indicating a larger root surface area in Typha. The two species had a similar P use efficiency (PUE) at 10 ??g PI-1 (mean = 1134 g dry weight g-1 P) and at 40 and 80 ??g PI-1 (mean = 482 dry weight g-1 P) but the N/P ratio indicated imbalances in nutrient uptake at a higher P concentration (40 ??g PI-1) in Typha than in Cladium (10 ??g PI-1). The two species had similar root specific P accumulation rate at the two lowest P levels, whereas Typha had 3-13-fold higher P uptake rates at the two highest P levels, indicating a higher nutrient uptake capacity in Typha. The experimental oxygen concentration in the rhizosphere had only limited effect on the growth of the two species and had little effect on biomass partitioning and nutrient use efficiency. The aerenchyma in these species was probably sufficient to maintain adequate root oxygenation under partially oxygen

  6. How Will Repealing the ACA Affect Medicaid? Impact on Health Care Coverage, Delivery, and Payment.

    PubMed

    Rosenbaum, Sara; Rothenberg, Sara; Schmucker, Sara; Gunsalus, Rachel; Beckerman, J. Zoë

    2017-03-01

    ISSUE: The Affordable Care Act enhanced Medicaid's role as a health care purchaser by expanding eligibility and broadening the range of tools and strategies available to states. All states have embraced delivery and payment reform as basic elements of their programs. GOAL: To examine the effects of reducing the size and scope of Medicaid under legislation to repeal the ACA. FINDINGS AND CONCLUSIONS: Were the ACA's Medicaid expansion to be eliminated and were federal Medicaid funding to experience major reductions through block grants or per capita caps, the effects on system transformation would be significant. Over 70 percent of Medicaid spending is driven by enrollment in a program that covers 74 million people; on a per capita basis Medicaid costs less than Medicare or commercial insurance. States would need to absorb major financial losses by reducing the number of people served, reducing the scope of services covered, introducing higher cost-sharing, or further reducing already low payments. Far from improving quality and efficiency, these changes would cause the number of uninsured to rise while depriving health care providers and health plans of the resources needed to care for patients and invest in the tools that are essential to system transformation

  7. [Soil nutrient accumulation and its affecting factors during vegetation succession in karst peak-cluster depressions of South China].

    PubMed

    Zhang, Wei; Wang, Ke-Lin; Liu, Su-Juan; Ye, Ying-Ying; Pan, Fu-Jing; He, Xu-Yang

    2013-07-01

    Taking the typical karst peak-cluster depressions in Huanjiang County of northwest Guangxi as the objects, and by using the method of replacing time with space, an analysis was made on the dynamic changes of top soil (0-15 cm) nutrients and their dominant controlling factors during the process of vegetation succession. With the positive succession of vegetation (herb-shrub-secondary forest-primary forest), the soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) contents increased significantly, with the soil SOC, TN, and TP increased from 29.1 g x kg(-1), 2.48 g x kg(-1), and 0.72 g x kg(-1) in herb community to 73.9 g x kg(-1), 8.10 g x kg(-1), and 1.6 g x kg(-1) in primary forest, respectively, which indicated that the positive succession of vegetation was helpful to the soil nutrient accumulation. The soil cation exchange capacity (CEC) had close relationships with the soil SOC and TN, being the primary controlling factor for the accumulation of the soil C and N. The litter P content, C/P ratio, and N/P ratio were the major factors controlling the P accumulation in the topsoil. The litters higher P content and N/P ratio and smaller C/P ratio were helpful for the P accumulation. Topographic indices (slope, aspect, and rock exposure ratio) had little effects on the soil nutrients.

  8. Poly(ethylenimine)-mediated gene delivery affects endothelial cell function and viability.

    PubMed

    Godbey, W T; Wu, K K; Mikos, A G

    2001-03-01

    Poly(ethylenimine) (PEI) was used to transfect the endothelial cell line EA.hy 926, and the secreted levels of three gene products, tissue-type plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1), and von Willebrand Factor (vWF), were assessed via ELISA. We found that the levels of these gene products in cell supernatants increased by factors up to 16.3 (tPA), 8.3 (PAI-1), or 6.7 (vWF) times the levels recorded for untreated cells, and roughly correlated with the percentage of cells that expressed the reporter plasmid. Transfections carried out using promotorless constructs of the same reporter plasmid also yielded increases in tPA, PAI-1, and vWF to similar extents. Additionally, data regarding cell viability were gathered and found to inversely relate to both the effectiveness of the PEI used for transfection and the secreted levels of the three mentioned products. There appeared to be two distinct types of cell death, resulting from the use of either free PEI (which acts within 2 h) or PEI/DNA complexes (which cause death 7-9 h after transfection). Cells were also transfected by poly(L-lysine) and liposomal carriers, and increases in secreted tPA similar to those seen with PEI-mediated transfection were observed for positively transfected cells. The results of these investigations indicate that non-viral gene delivery can induce a state of endothelial cell dysfunction, and that PEI-mediated transfection can lead to two distinct types of cell death.

  9. Nonclinical factors affecting women's access to trial of labor after cesarean delivery.

    PubMed

    Korst, Lisa M; Gregory, Kimberly D; Fridman, Moshe; Phelan, Jeffrey P

    2011-06-01

    The use of trial of labor after cesarean (TOLAC) has declined in the last decade, and the clinical risks of TOLAC remain low. Nonclinical factors continue to affect women's access to TOLAC. This article considers 5 categories of factors that seem to be influencing rates of TOLAC and vaginal birth after cesarean: opinion leaders and professional guidelines, hospital facilities and cesarean availability, reimbursement for providing TOLAC, medical liability, and patient-level factors. An evidence base and strategies to provide guidance to create a safe environment for vaginal birth after cesarean are needed. Obstetric information systems are critical to this effort.

  10. Interactions between repeated fire, nutrients, and insect herbivores affect the recovery of diversity in the southern Amazon.

    PubMed

    Massad, Tara Joy; Balch, Jennifer K; Davidson, Eric A; Brando, Paulo M; Mews, Cândida Lahís; Porto, Pábio; Quintino, Raimundo Mota; Vieira, Simone A; Junior, Ben Hur Marimon; Trumbore, Susan E

    2013-05-01

    Surface fires burn extensive areas of tropical forests each year, altering resource availability, biotic interactions, and, ultimately, plant diversity. In transitional forest between the Brazilian cerrado (savanna) and high stature Amazon forest, we took advantage of a long-term fire experiment to establish a factorial study of the interactions between fire, nutrient availability, and herbivory on early plant regeneration. Overall, five annual burns reduced the number and diversity of regenerating stems. Community composition changed substantially after repeated fires, and species common in the cerrado became more abundant. The number of recruits and their diversity were reduced in the burned area, but burned plots closed to herbivores with nitrogen additions had a 14 % increase in recruitment. Diversity of recruits also increased up to 50 % in burned plots when nitrogen was added. Phosphorus additions were related to an increase in species evenness in burned plots open to herbivores. Herbivory reduced seedling survival overall and increased diversity in burned plots when nutrients were added. This last result supports our hypothesis that positive relationships between herbivore presence and diversity would be strongest in treatments that favor herbivory--in this case herbivory was higher in burned plots which were initially lower in diversity. Regenerating seedlings in less diverse plots were likely more apparent to herbivores, enabling increased herbivory and a stronger signal of negative density dependence. In contrast, herbivores generally decreased diversity in more species rich unburned plots. Although this study documents complex interactions between repeated burns, nutrients, and herbivory, it is clear that fire initiates a shift in the factors that are most important in determining the diversity and number of recruits. This change may have long-lasting effects as the forest progresses through succession.

  11. Nutrient-based ecological consideration of a temporary river catchment affected by a reservoir operation to facilitate efficient management.

    PubMed

    Tzoraki, Ourania A; Dörflinger, Gerald; Kathijotes, Nicholas; Kontou, Artemis

    2014-01-01

    The water quality status of the Kouris river in Cyprus was examined in order to fulfil the requirements for ecological quality as defined by the Water Framework Directive-2000/60/EC. Nitrate concentration (mean value) was increased in the Limnatis (2.8 mg L(-1)) tributary in comparison with the Kryos (2.1 mg L(-1)) and Kouris (1.0 mg L(-1)) tributaries depicting the influence of anthropogenic activities. The total maximum daily nutrients loads (TMDLs) based on the flow duration curves approach, showed that nutrients loads exceeded threshold values (33.3-75.6% in all hydrologic condition classes in the Kouris tributary, and 65-78% in the Limnatis tributary) especially under low flow conditions. The TMDL graph is intended to guide the temporal schedule for chemical sampling in all hydrologic classes. Kouris reservoir is an oligotrophic system, strongly influenced by the river's flash-flood character but also by the implemented management practices. Kouris river outflow, which was reduced to one-tenth in the post dam period altered the wetland hydrologic network and contributed to the decrease of aquifer thickness. Continuous evaluation and update of the River Basin Management Plans will be the basis for the sustainable development of the Kouris basin.

  12. Nutrient limitation leads to penetrative growth into agar and affects aroma formation in Pichia fabianii, P. kudriavzevii and Saccharomyces cerevisiae.

    PubMed

    van Rijswijck, Irma M H; Dijksterhuis, Jan; Wolkers-Rooijackers, Judith C M; Abee, Tjakko; Smid, Eddy J

    2015-01-01

    Among fermentative yeast species, Saccharomyces cerevisiae is most frequently used as a model organism, although other yeast species may have special features that make them interesting candidates to apply in food-fermentation processes. In this study, we used three yeast species isolated from fermented masau (Ziziphus mauritiana) fruit, S. cerevisiae 131, Pichia fabianii 65 and Pichia kudriavzevii 129, and determined the impact of nitrogen and/or glucose limitation on surface growth mode and the production of volatile organic compounds (VOCs). All three species displayed significant changes in growth mode in all nutrient-limited conditions, signified by the formation of metafilaments or pseudohyphae. The timing of the transition was found to be species-specific. Transition in growth mode is suggested to be linked to the production of certain fusel alcohols, such as phenylethyl alcohol, which serve as quorum-sensing molecules. Interestingly, we did not observe concomitant increased production of phenylethyl alcohol and filamentous growth. Notably, a broader range of esters was found only for the Pichia spp. grown on nitrogen-limited agar for 21 days compared to nutrient-rich agar, and when grown on glucose- and glucose- plus nitrogen-limited agar. Our data suggest that for the Pichia spp., the formation of esters may play an important role in the switch in growth mode upon nitrogen limitation. Further biological or ecological implications of ester formation are discussed.

  13. Digestate color and light intensity affect nutrient removal and competition phenomena in a microalgal-bacterial ecosystem.

    PubMed

    Marcilhac, Cyril; Sialve, Bruno; Pourcher, Anne-Marie; Ziebal, Christine; Bernet, Nicolas; Béline, Fabrice

    2014-11-01

    During anaerobic digestion, nutrients are mineralized and may require post-treatment for optimum valorization. The cultivation of autotrophic microalgae using the digestate supernatant is a promising solution; however the dark color of the influent poses a serious problem. First, the color of the digestates was studied and the results obtained using three different digestates demonstrated a strong heterogeneity although their color remained rather constant over time. The digestates absorbed light over the whole visible spectrum and remained colored even after a ten-fold dilution. Secondly, the impact of light and of substrate color on the growth of Scenedesmus sp. and on nitrogen removal were assessed. These experiments led to the construction of a model for predicting the impact of influent color and light intensity on N removal. Maximum N removal (8.5 mgN- [Formula: see text]  L(-1) d(-1)) was observed with an initial optical density of 0.221 and 244 μmolE m(-)² s(-1) light and the model allows to determine N removal between 15.9 and 22.7 mgN- [Formula: see text]  L(-1) d(-1) in real conditions according to the dilution level of the influent and related color. Changes in the microalgae community were monitored and revealed the advantage of Chlorella over Scenedesmus under light-limitation. Additionally microalgae outcompeted nitrifying bacteria and experiments showed how microalgae become better competitors for nutrients when phosphorus is limiting. Furthermore, nitrification was limited by microalgae growth, even when P was not limiting.

  14. Delivery fee exemption and subsidy policies: how have they affected health staff? Findings from a four-country evaluation.

    PubMed

    Witter, Sophie; Ilboudo, Patrick G; Cunden, Nadia; Boukhalfa, Chakib; Makoutode, Patrick; Daou, Zoumana

    2016-08-30

    Many countries, especially in Africa, have in recent years introduced fee exemptions or subsidies targeting deliveries and emergency obstetric care. A number of aspects of these policies have been studied but there are few studies which look at how staff have been affected and how they have responded. This article focuses on this question, comparing data from Benin, Burkina Faso, Mali and Morocco. It is nested in wider evaluation of the policies. The article analyses responses to a health worker survey, carried out in 2012 on 683 health staff (doctors, nurses, midwives and others such as auxiliaries) across the four countries. The survey focused on working hours, workloads, pay, motivation and perceptions of the policies, as well as reported changes in workload and remuneration over the period of policy introduction. Self-reported staff output ratios suggest that midwives are over-worked across all settings, but facility data presents lower estimates, making it hard to judge the adequacy of workforces. Staff are generally positive about the policies' effects on the health system (increasing supervised delivery rates, benefiting the poor, improving access to medicines and supplies and improving quality of care). In personal terms, staff in Mali and Burkina Faso report increased satisfaction with work as a result of the policies, while in Benin, there is little change and in Morocco a deterioration (which correlated with recommendations about extending exemption policies in future). Awareness of policies was high amongst staff but only a small minority had received any written guides or training on policy implementation. It is crucial that planned health financing changes engage with their implications for staffing-estimating whether specific cadres can absorb increase demand, for example, as well as how to engage them in the policy implementation such that their personal needs are met and their professionalism enhanced.

  15. Parameters affecting the efficient delivery of mesoporous silica nanoparticle materials and gold nanorods into plant tissues by the biolistic method.

    PubMed

    Martin-Ortigosa, Susana; Valenstein, Justin S; Sun, Wei; Moeller, Lorena; Fang, Ning; Trewyn, Brian G; Lin, Victor S-Y; Wang, Kan

    2012-02-06

    Applying nanotechnology to plant science requires efficient systems for the delivery of nanoparticles (NPs) to plant cells and tissues. The presence of a cell wall in plant cells makes it challenging to extend the NP delivery methods available for animal research. In this work, research is presented which establishes an efficient NP delivery system for plant tissues using the biolistic method. It is shown that the biolistic delivery of mesoporous silica nanoparticle (MSN) materials can be improved by increasing the density of MSNs through gold plating. Additionally, a DNA-coating protocol is used based on calcium chloride and spermidine for MSN and gold nanorods to enhance the NP-mediated DNA delivery. Furthermore, the drastic improvement of NP delivery is demonstrated when the particles are combined with 0.6 μm gold particles during bombardment. The methodology described provides a system for the efficient delivery of NPs into plant cells using the biolistic method.

  16. Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids: Part II. Effects on intestinal histology and active nutrient transport.

    PubMed

    Walsh, M C; Rostagno, M H; Gardiner, G E; Sutton, A L; Richert, B T; Radcliffe, J S

    2012-08-01

    The objective of this study was to evaluate the effects of water-delivered, direct-fed microbials (DFM) or organic acids on intestinal morphology and active nutrient absorption in weanling pigs after deliberate Salmonella infection. Pigs (n = 88) were weaned at 19 ± 2 d of age and assigned to 1 of the following treatments, which were administered for 14 d: 1) control diet; 2) control diet + DFM (Enterococcus faecium, Bacillus subtilis, and Bacillus licheniformis) in drinking water at 10(9) cfu/L for each strain of bacteria; 3) control diet + organic acid-based blend (predominantly propionic, acetic, and benzoic acids) in drinking water at 2.58 mL/L; and 4) control diet + 55 mg/kg carbadox. Pigs were challenged with 10(10) cfu Salmonella enterica var Typhimurium 6 d after commencement of treatments. Pigs (n = 22/d) were harvested before Salmonella challenge and on d 2, 4, and 8 after challenge. Duodenal, jejunal, and ileal mucosal tissues were sampled for measurement of villus height and crypt depth. Jejunal tissue was sampled for determination of active nutrient absorption in modified Ussing chambers. Duodenal villus height was greater in pigs fed in-feed antibiotic before infection (P < 0.05). Jejunal crypts were deeper in DFM- and acid-treated pigs on d 4 after infection compared with all other treatments (P < 0.05). Salmonella infection resulted in a linear decrease in phosphorus (P < 0.001) and glucose (P < 0.05) active transport, and an increase (P < 0.001) in glutamine uptake immediately after challenge. Salmonella infection reduced basal short-circuit current (I(sc)); however, water-delivered DFM or organic acid treatments caused greater basal I(sc) on d 2 after challenge than did carbadox. Carbachol-induced chloride ion secretion was greatest in negative control pigs before infection (P < 0.01) and DFM-treated pigs (P < 0.05) after infection. In conclusion, both the DFM and acidification treatments induced increases in basal active ion movement and jejunal

  17. The Novel Membrane-Bound Proteins MFSD1 and MFSD3 are Putative SLC Transporters Affected by Altered Nutrient Intake.

    PubMed

    Perland, Emelie; Hellsten, Sofie V; Lekholm, Emilia; Eriksson, Mikaela M; Arapi, Vasiliki; Fredriksson, Robert

    2017-02-01

    Membrane-bound solute carriers (SLCs) are essential as they maintain several physiological functions, such as nutrient uptake, ion transport and waste removal. The SLC family comprise about 400 transporters, and we have identified two new putative family members, major facilitator superfamily domain containing 1 (MFSD1) and 3 (MFSD3). They cluster phylogenetically with SLCs of MFS type, and both proteins are conserved in chordates, while MFSD1 is also found in fruit fly. Based on homology modelling, we predict 12 transmembrane regions, a common feature for MFS transporters. The genes are expressed in abundance in mice, with specific protein staining along the plasma membrane in neurons. Depriving mouse embryonic primary cortex cells of amino acids resulted in upregulation of Mfsd1, whereas Mfsd3 is unaltered. Furthermore, in vivo, Mfsd1 and Mfsd3 are downregulated in anterior brain sections in mice subjected to starvation, while upregulated specifically in brainstem. Mfsd3 is also attenuated in cerebellum after starvation. In mice raised on high-fat diet, Mfsd1 was specifically downregulated in brainstem and hypothalamus, while Mfsd3 was reduced consistently throughout the brain.

  18. Nanosilver and Nano Zero-Valent Iron Exposure Affects Nutrient Exchange Across the Sediment-Water Interface.

    PubMed

    Buchkowski, Robert W; Williams, Clayton J; Kelly, Joel; Veinot, Jonathan G C; Xenopoulos, Marguerite A

    2016-01-01

    To examine how nanoparticles influence biogeochemical cycles in streams, we studied the acute impact of nanosilver (nAg) and nanoparticulate zero-valent iron (nZVI) exposure on nutrient and oxygen exchange across the sediment-water interface of two streams (agricultural canal and wetland) that differed in their water quality and sediment characteristics. At the agricultural site, nAg increased oxygen consumption and decreased N2 flux rates from that observed in control incubations. nZVI caused sediment-water systems from both streams to go hypoxic within 1.5 h of exposure. N2 flux rates were at least an order of magnitude higher in nZVI treatments as compared to control. Water column nitrate and nitrite concentrations were not impacted by nZVI exposure but total dissolved phosphorus concentrations were higher in cores treated with nZVI. nAg and nZVI exposure to surface water ecosystems can disrupt ecological function across the sediment-water interface.

  19. Tomato growth as affected by root-zone temperature and the addition of gibberellic acid and kinetin to nutrient solutions

    NASA Technical Reports Server (NTRS)

    Bugbee, B.; White, J. W.; Salisbury, F. B. (Principal Investigator)

    1984-01-01

    The effect of root-zone temperature on young tomato plants (Lycopersicon esculentum Mill. cv. Heinz 1350) was evaluated in controlled environments using a recirculating solution culture system. Growth rates were measured at root-zone temperatures of 15 degrees, 20 degrees, 25 degrees, and 30 degrees C in a near optimum foliar environment. Optimum growth occurred at 25 degrees to 30 degrees during the first 4 weeks of growth and 20 degrees to 25 degrees during the 5th and 6th weeks. Growth was severely restricted at 15 degrees. Four concentrations of gibberellic acid (GA3) and kinetin were added to the nutrient solution in a separate trial; root-zone temperature was maintained at 15 degrees and 25 degrees. Addition of 15 micromoles GA3 to solutions increased specific leaf area, total leaf area, and dry weight production of plants in both temperature treatments. GA3-induced growth stimulation was greater at 15 degrees than at 25 degrees. GA3 may promote growth by increasing leaf area, enhancing photosynthesis per unit leaf area, or both. Kinetic was not useful in promoting growth at either temperature.

  20. Factors Affecting the Involvement of Day Centre Care Staff in the Delivery of Physiotherapy to Adults with Intellectual Disabilities: An Exploratory Study in One London Borough

    ERIC Educational Resources Information Center

    Middleton, M. -J.; Kitchen, S. S.

    2008-01-01

    Background: Physiotherapists for adults with intellectual disabilities often work in day centres, relying on care staff to support programmes. This study investigates factors affecting physiotherapy delivery in 4 day centres in one London borough. Materials and Method: Semi-structured interviews were carried out with day centre care staff,…

  1. Identification of multiple cellular uptake pathways of polystyrene nanoparticles and factors affecting the uptake: relevance for drug delivery systems.

    PubMed

    Firdessa, Rebuma; Oelschlaeger, Tobias A; Moll, Heidrun

    2014-01-01

    Nanoparticles may address challenges by human diseases through improving diagnosis, vaccination and treatment. The uptake mechanism regulates the type of threat a particle poses on the host cells and how a cell responds to it. Hence, understanding the uptake mechanisms and cellular interactions of nanoparticles at the cellular and subcellular level is a prerequisite for their effective biomedical applications. The present study shows the uptake mechanisms of polystyrene nanoparticles and factors affecting their uptake in bone marrow-derived macrophages, 293T kidney epithelial cells and L929 fibroblasts. Labeling with the endocytic marker FM4-64 and transmission electron microscopy studies show that the nanoparticles were internalized rapidly via endocytosis and accumulated in intracellular vesicles. Soon after their internalizations, nanoparticles trafficked to organelles with acidic pH. Analysis of the ultrastructural morphology of the plasma membrane invaginations or extravasations provides clear evidence for the involvement of several uptake routes in parallel to internalize a given type of nanoparticles by mammalian cells, highlighting the complexity of the nanoparticle-cell interactions. Blocking the specific endocytic pathways by different pharmacological inhibitors shows similar outcomes. The potential to take up nanoparticles varies highly among different cell types in a particle sizes-, time- and energy-dependent manner. Furthermore, infection and the activation status of bone marrow-derived macrophages significantly affect the uptake potential of the cells, indicating the need to understand the diseases' pathogenesis to establish effective and rational drug-delivery systems. This study enhances our understanding of the application of nanotechnology in biomedical sciences.

  2. Pregnancy outcomes, site of delivery, and community schisms in regions affected by the armed conflict in Chiapas, Mexico.

    PubMed

    Brentlinger, Paula E; Sánchez-Pérez, Héctor Javier; Cedeño, Marcos Arana; Morales, Lic Guadalupe Vargas; Hernán, Miguel A; Micek, Mark A; Ford, Douglas

    2005-09-01

    The Zapatista armed conflict began in the state of Chiapas, Mexico, in 1994, and overlaps pre-existing local disputes about land, religion, and other issues. Related disruptions in access to and utilization of health services have been alleged to have compromised local health status, particularly in vulnerable subgroups such as indigenous women and infants. The study objective was to measure maternal and perinatal mortality ratios and utilization of pregnancy-related health services in the region affected by the Zapatista conflict, and to describe associations between these primary outcome measures, socioeconomic and demographic factors, and factors associated with inter-party and intra-community conflict. A cross-sectional, population-based survey was conducted in 46 communities in three regions. The study subjects were 1227 women, 13-49 years old, who had been pregnant during the preceding 2 years (1999-2001). Principal outcome measures were maternal and perinatal mortality, and site of delivery. Secondary analyses explored associations between primary outcomes and socioeconomic, demographic, and conflict-related factors. Most births (87.1%) occurred at home. The crude observed maternal and perinatal mortality ratios were 607/100,000 and 23.5/1000 live births, respectively. Those who died had difficulty accessing emergency obstetrical care. Both home birth and mortality were associated with descriptors of intra-community conflict. Observed maternal and perinatal mortality ratios were substantially higher than those officially reported for Mexico or Chiapas. Reduction of high reproductive mortality ratios will require attention to socioeconomic and conflict-related problems, in addition to improved access to emergency obstetrical services.

  3. Putative Membrane-Bound Transporters MFSD14A and MFSD14B Are Neuronal and Affected by Nutrient Availability

    PubMed Central

    Lekholm, Emilia; Perland, Emelie; Eriksson, Mikaela M.; Hellsten, Sofie V.; Lindberg, Frida A.; Rostami, Jinar; Fredriksson, Robert

    2017-01-01

    Characterization of orphan transporters is of importance due to their involvement in cellular homeostasis but also in pharmacokinetics and pharmacodynamics. The tissue and cellular localization, as well as function, is still unknown for many of the solute carriers belonging to the major facilitator superfamily (MFS) Pfam clan. Here, we have characterized two putative novel transporters MFSD14A (HIAT1) and MFSD14B (HIATL1) in the mouse central nervous system and found protein staining throughout the adult mouse brain. Both transporters localized to neurons and MFSD14A co-localized with the Golgi marker Giantin in primary embryonic cortex cultures, while MFSD14B staining co-localized with an endoplasmic retention marker, KDEL. Based on phylogenetic clustering analyses, we predict both to have organic substrate profiles, and possible involvement in energy homeostasis. Therefore, we monitored gene regulation changes in mouse embryonic primary cultures after amino acid starvations and found both transporters to be upregulated after 3 h of starvation. Interestingly, in mice subjected to 24 h of food starvation, both transporters were downregulated in the hypothalamus, while Mfsd14a was also downregulated in the brainstem. In addition, in mice fed a high fat diet (HFD), upregulation of both transporters was seen in the striatum. Both MFSD14A and MFSD14B were intracellular neuronal membrane-bound proteins, expressed in the Golgi and Endoplasmic reticulum, affected by both starvation and HFD to varying degree in the mouse brain. PMID:28179877

  4. Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids: Part II. Effects on intestinal histology and active nutrient transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate the effects of water-delivered direct-fed microbials (DFM) or organic acids on intestinal morphology and active nutrient absorption in weanling pigs following deliberate Salmonella infection. Pigs (n = 88) were weaned at 19 ± 2 d of age and assigned to one...

  5. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States1

    PubMed Central

    Rebich, Richard A; Houston, Natalie A; Mize, Scott V; Pearson, Daniel K; Ging, Patricia B; Evan Hornig, C

    2011-01-01

    Abstract SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). PMID:22457582

  6. Surface-water nutrient conditions and sources in the United States Pacific Northwest

    USGS Publications Warehouse

    Wise, D.R.; Johnson, H.M.

    2011-01-01

    The SPAtially Referenced Regressions On Watershed attributes (SPARROW) model was used to perform an assessment of surface-water nutrient conditions and to identify important nutrient sources in watersheds of the Pacific Northwest region of the United States (U.S.) for the year 2002. Our models included variables representing nutrient sources as well as landscape characteristics that affect nutrient delivery to streams. Annual nutrient yields were higher in watersheds on the wetter, west side of the Cascade Range compared to watersheds on the drier, east side. High nutrient enrichment (relative to the U.S. Environmental Protection Agency's recommended nutrient criteria) was estimated in watersheds throughout the region. Forest land was generally the largest source of total nitrogen stream load and geologic material was generally the largest source of total phosphorus stream load generated within the 12,039 modeled watersheds. These results reflected the prevalence of these two natural sources and the low input from other nutrient sources across the region. However, the combined input from agriculture, point sources, and developed land, rather than natural nutrient sources, was responsible for most of the nutrient load discharged from many of the largest watersheds. Our results provided an understanding of the regional patterns in surface-water nutrient conditions and should be useful to environmental managers in future water-quality planning efforts.

  7. Prevalence of hospitalized live births affected by alcohol and drugs and parturient women diagnosed with substance abuse at liveborn delivery: United States, 1999-2008.

    PubMed

    Pan, I-Jen; Yi, Hsiao-ye

    2013-05-01

    To describe prevalence trends in hospitalized live births affected by placental transmission of alcohol and drugs, as well as prevalence trends among parturient women hospitalized for liveborn delivery and diagnosed with substance abuse problems in the United States from 1999 to 2008. Comparison of the two sets of trends helps determine whether the observed changes in neonatal problems over time were caused by shifts in maternal substance abuse problems. This study independently identified hospitalized live births and maternal live born deliveries from discharge records in the Nationwide Inpatient Sample, one of the largest hospital administrative databases. Substance-related diagnosis codes on the records were used to identify live births affected by alcohol and drugs and parturient women with substance abuse problems. The analysis calculated prevalence differences and percentage changes over the 10 years, with Loess curves fitted to 10-year prevalence estimates to depict trend patterns. Linear and quadratic trends in prevalence were simultaneously tested using logistic regression analyses. The study also examined data on costs, primary expected payer, and length of hospital stays. From 1999 to 2008, prevalence increased for narcotic- and hallucinogen-affected live births and neonatal drug withdrawal syndrome but decreased for alcohol- and cocaine-affected live births. Maternal substance abuse at delivery showed similar trends, but prevalence of alcohol abuse remained relatively stable. Substance-affected live births required longer hospital stays and higher medical expenses, mostly billable to Medicaid. The findings highlight the urgent need for behavioral intervention and early treatment for substance-abusing pregnant women to reduce the number of substance-affected live births.

  8. Meal frequency changes the basal and time-course profiles of plasma nutrient concentrations and affects feed efficiency in young growing pigs.

    PubMed

    Le Naou, T; Le Floc'h, N; Louveau, I; van Milgen, J; Gondret, F

    2014-05-01

    Ingested dietary nutrients and feed energy are partitioned among tissues to sustain body growth. Based on the respective costs of the various metabolic pathways allowing use and storage of feed energy into cells, it may be theorized that daily meal frequency could affect growth, body composition or feed efficiency. This study aimed to determine the effects of daily meal frequency on nutrient partitioning, tissue metabolism and composition, and performance. Young growing pigs (30 kg BW) were offered a same amount of feed either in 2 (M2, n = 15) or 12 (M12, n = 16) meals per day during a 3-wk interventional period. Animals fed twice a day had an accelerated weight gain (+6.4%, P < 0.05) and exhibited a greater G:F (+4%, P = 0.03) than animals fed 12 meals per day during this period. Basal plasma concentrations of glucose, lactate, triglyceride, urea, and leptin were lower (P < 0.001) in M2 pigs than in M12 pigs. Meal frequency also changed (P < 0.001) the time-course profiles of plasma concentrations of glucose, insulin, and lactate in response to meal ingestion. A greater rise and a sharper fall in plasma glucose and insulin levels were observed in M2 pigs compared with M12 pigs. In both groups, similarities were observed in the postprandial time courses of plasma concentrations of insulin and of α-amino nitrogen (used as a measure of total AA). Despite these metabolic responses, tissue lipids, glycogen content, and enzyme activities participating in energy metabolism in muscle and liver were similar (P > 0.10) in both groups at the end of the trial. Percentage of perirenal fat in the body and depth of dorsal subcutaneous fat tissue were not affected by meal frequency, but kidney weight was lower (-18%, P < 0.001) in M2 pigs than in M12 pigs. Altogether, the less frequent daily meal intake improves the conversion of feed into weight gain, without marked modifications of tissue composition in young pigs.

  9. Drug-nutrient interactions.

    PubMed

    Chan, Lingtak-Neander

    2013-07-01

    Drug-nutrient interactions are defined as physical, chemical, physiologic, or pathophysiologic relationships between a drug and a nutrient. The causes of most clinically significant drug-nutrient interactions are usually multifactorial. Failure to identify and properly manage drug-nutrient interactions can lead to very serious consequences and have a negative impact on patient outcomes. Nevertheless, with thorough review and assessment of the patient's history and treatment regimens and a carefully executed management strategy, adverse events associated with drug-nutrient interactions can be prevented. Based on the physiologic sequence of events after a drug or a nutrient has entered the body and the mechanism of interactions, drug-nutrient interactions can be categorized into 4 main types. Each type of interaction can be managed using similar strategies. The existing data that guide the clinical management of most drug-nutrient interactions are mostly anecdotal experience, uncontrolled observations, and opinions, whereas the science in understanding the mechanism of drug-nutrient interactions remains limited. The challenge for researchers and clinicians is to increase both basic and higher level clinical research in this field to bridge the gap between the science and practice. The research should aim to establish a better understanding of the function, regulation, and substrate specificity of the nutrient-related enzymes and transport proteins present in the gastrointestinal tract, as well as assess how the incidence and management of drug-nutrient interactions can be affected by sex, ethnicity, environmental factors, and genetic polymorphisms. This knowledge can help us develop a true personalized medicine approach in the prevention and management of drug-nutrient interactions.

  10. Long-term experimental warming, shading and nutrient addition affect the concentration of phenolic compounds in arctic-alpine deciduous and evergreen dwarf shrubs.

    PubMed

    Hansen, Anja H; Jonasson, Sven; Michelsen, Anders; Julkunen-Tiitto, Riitta

    2006-02-01

    Environmental changes are likely to alter the chemical composition of plant tissues, including content and concentrations of secondary compounds, and thereby affect the food sources of herbivores. After 10 years of experimental increase of temperature, nutrient levels and light attenuation in a sub-arctic, alpine ecosystem, we investigated the effects on carbon based secondary compounds (CBSC) and nitrogen in one dominant deciduous dwarf shrub, Salix herbacea x polaris and two dominant evergreen dwarf shrubs, Cassiope tetragona and Vaccinium vitis-idaea throughout one growing season. The main aims were to compare the seasonal course and treatment effects on CBSC among the species, life forms and leaf cohorts and to examine whether the responses in different CBSC were consistent across compounds. The changes in leaf chemistry both during the season and in response to the treatments were higher in S. herbacea x polaris than in the corresponding current year's leaf cohort of the evergreen C. tetragona. The changes were also much higher than in the 1-year-old leaves of the two evergreens probably due to differences in dilution and turnover of CBSC in growing and mature leaves paired with different rates of allocation. Most low molecular weight phenolics in the current year's leaves decreased in all treatments. Condensed tannins and the tannin-to-N ratio, however, either increased or decreased, and the strength and even direction of the responses varied among the species and leaf cohorts, supporting views of influential factors additional to resource-based or developmental controls, as e.g. species specific or genetic controls of CBSC. The results indicate that there is no common response to environmental changes across species and substances. However, the pronounced treatment responses imply that the quality of the herbivore forage is likely to be strongly affected in a changing arctic environment, although both the direction and strength of the responses will be

  11. Do targeted written comments and the rubric method of delivery affect performance on future human physiology laboratory reports?

    PubMed

    Clayton, Zachary S; Wilds, Gabriel P; Mangum, Joshua E; Hocker, Austin D; Dawson, Sierra M

    2016-09-01

    We investigated how students performed on weekly two-page laboratory reports based on whether the grading rubric was provided to the student electronically or in paper form and the inclusion of one- to two-sentence targeted comments. Subjects were registered for a 289-student, third-year human physiology class with laboratory and were randomized into four groups related to rubric delivery and targeted comments. All students received feedback via the same detailed grading rubric. At the end of the term, subjects provided consent and a self-assessment of their rubric viewing rate and preferences. There were no differences in laboratory report scores between groups (P = 0.86), although scores did improve over time (P < 0.01). Students receiving targeted comments self-reported viewing their rubric more often than students that received no comments (P = 0.02), but the viewing rate was independent of the rubric delivery method (P = 0.15). Subjects with high rubric viewing rates did not have higher laboratory report grades than subjects with low viewing rates (P = 0.64). When asked about their preference for the future, 43% of respondents preferred the same method again (electronic or paper rubric) and 25% had no preference. We conclude that although student laboratory report grades improved over time, the rate and degree of improvement were not related to rubric delivery method or to the inclusion of targeted comments.

  12. Bone Regeneration Mediated by BMP4-Expressing Muscle-Derived Stem Cells Is Affected by Delivery System

    PubMed Central

    Usas, Arvydas; Ho, Andrew M.; Cooper, Gregory M.; Olshanski, Anne; Peng, Hairong

    2009-01-01

    This study investigated the delivery of bone morphogenetic protein (BMP)4-secreting muscle-derived stem cells (MDSC-B4) capable of inducing bone formation in mice using collagen gel (CG), fibrin sealant (FS), and gelatin sponge carriers. After implanting these various cell-loaded scaffolds intramuscularly or into critical-size skull defects, we measured the extent of heterotopic ossification and calvarial defect healing over a 6-week period via radiographic, radiomorphometric, histological, and micro-computed tomography analyses. As expected, in the absence of MDSC-B4, there was no ectopic ossification and only minimal calvarial regeneration using each type of scaffold. Although CG and gelatin sponges loaded with BMP4-secreting cells produced the most ectopic bone, FS constructs produced bone with comparably less mineralization. In the mouse calvaria, we observed MDSC-B4-loaded scaffolds able to promote bone defect healing to a variable degree, but there were differences between these implants in the volume, shape, and morphology of regenerated bone. MDSC-B4 delivery in a gelatin sponge produced hypertrophic bone, whereas delivery in a CG and FS healed the defect with bone that closely resembled the quantity and configuration of native calvarium. In summary, hydrogels are suitable carriers for osteocompetent MDSCs in promoting bone regeneration, especially at craniofacial injury sites. PMID:19061430

  13. Transformations of Heavy Metals and Plant Nutrients in Dredged Sediments as Affected by Oxidation Reduction Potential and pH. Volume 1. Literature Review

    DTIC Science & Technology

    1977-05-01

    to account for the observed retention were the formation of a clay -organic complex , en- trapment of organic molecules or the alteration of organic...rather than a source. This clay -organic complex may serve as a sink for nutrient elements, toxic metals, and organic contaminants and thereby remove...nutrients, organo -metallic complexes may also influence the transport and fixation of toxic elements, which are important phenomena in sediments and dredged

  14. Ocean nutrients

    NASA Astrophysics Data System (ADS)

    Boyd, Philip W.; Hurd, Catriona L.

    Nutrients provide the chemical life-support system for phytoplankton in the ocean. Together with the carbon fixed during photosynthesis, nutrients provide the other elements, such as N and P, needed to synthesize macromolecules to build cellular constituents such as ribosomes. The makeup of these various biochemicals, such as proteins, pigments, and nucleic acids, together determine the elemental stoichiometry of an individual phytoplankton cell. The stoichiometry of different phytoplankton species or groups will vary depending on the proportions of distinct cellular machinery, such as for growth or resource acquisition, they require for their life strategies. The uptake of nutrients by phytoplankton helps to set the primary productivity, and drives the biological pump, of the global ocean. In the case of nitrogen, the supply of nutrients is categorized as either new or regenerated. The supply of new nitrogen, such as nitrate upwelled from the ocean' interior or biological nitrogen fixation, is equal to the vertical export of particular organic matter from the upper ocean on a timescale of years. Nutrients such as silica can also play a structural role in some phytoplankton groups, such as diatoms, where they are used to synthesize a siliceous frustule that offers some mechanical protection from grazers. In this chapter, we also explore nutrient uptake kinetics, patterns in nutrient distributions in space and time, the biogeochemical cycle of nitrogen, the atmospheric supply of nutrients, departures from the Redfield ratio, and whether nutrient distributions and cycling will be altered in the future

  15. Nutrient management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient management has been defined as “the science and art directed to link soil, crop, weather and hydrologic factors with cultural, irrigation and soil and water conservation practices to achieve the goals of optimizing nutrient use efficiency, yields, crop quality, and economic returns, while r...

  16. Available nutrients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar technology may contribute to the recovery and recycling of plant nutrients and thus add a fertilizer value to the biochar. Total nutrient content in biochars varies greatly and is mainly dependent on feedstock elemental composition and to a lesser extent on pyrolysis conditions. Availability...

  17. Are large macroalgal blooms necessarily bad? Nutrient impacts on seagrass in upwelling-influenced estuaries.

    PubMed

    Hessing-Lewis, Margot L; Hacker, Sally D; Menge, Bruce A; McConville, Sea-oh; Henderson, Jeremy

    2015-07-01

    Knowledge of nutrient pathways and their resulting ecological interactions can alleviate numerous environmental problems associated with nutrient increases in both natural and managed systems. Although not unique, coastal systems are particularly prone to complex ecological interactions resulting from nutrient inputs from both the land and sea. Nutrient inputs to coastal systems often spur ulvoid macroalgal blooms, with negative consequences for seagrasses, primarily through shading, as well as through changes in local biogeochemistry. We conducted complementary field and mesocosm experiments in an upwelling-influenced estuary, where marine-derived nutrients dominate, to understand the direct and indirect effects of nutrients on the macroalgal-eelgrass (Zostera marina L.) interaction. In the field experiment, we found weak evidence that nutrients and/or macroalgal treatments had a negative effect on eelgrass. However, in the mesocosm experiment, we found that a combination of nutrient and macroalgal treatments led to strongly negative eelgrass responses, primarily via indirect effects associated with macroalgal additions. Together, increased total light attenuation and decreased sediment oxygen levels were associated with larger effects on eelgrass than shading alone, which was evaluated using mimic algae treatments that did not alter sediment redox potential. Nutrient addition in the mesocosms directly affected seagrass density; biomass, and morphology, but not as strongly as macroalgae. We hypothesize that the contrary results from these parallel experiments are a consequence of differences in the hydrodynamics between field and mesocosm settings. We suggest that the high rates of water movement and tidal submersion of our intertidal field experiments alleviated the light reduction and negative biogeochemical changes in the sediment associated with macroalgal canopies, as well as the nutrient effects observed in the mesocosm experiments. Furthermore, adaptation

  18. Egg storage duration and hatch window affect gene expression of nutrient transporters and intestine morphological parameters of early hatched broiler chicks.

    PubMed

    Yalcin, S; Gursel, I; Bilgen, G; Izzetoglu, G T; Horuluoglu, B H; Gucluer, G

    2016-05-01

    In recent years, researchers have given emphasis on the differences in physiological parameters between early and late hatched chicks within a hatch window. Considering the importance of intestine development in newly hatched chicks, however, changes in gene expression of nutrient transporters in the jejunum of early hatched chicks within a hatch window have not been studied yet. This study was conducted to determine the effects of egg storage duration before incubation and hatch window on intestinal development and expression of PepT1 (H+-dependent peptide transporter) and SGLT1 (sodium-glucose co-transporter) genes in the jejunum of early hatched broiler chicks within a 30 h of hatch window. A total of 1218 eggs obtained from 38-week-old Ross 308 broiler breeder flocks were stored for 3 (ES3) or 14 days (ES14) and incubated at the same conditions. Eggs were checked between 475 and 480 h of incubation and 40 chicks from each egg storage duration were weighed; chick length and rectal temperature were measured. The chicks were sampled to evaluate morphological parameters and PepT1 and SGLT1 expression. The remaining chicks that hatched between 475 and 480 h were placed back in the incubator and the same measurements were conducted with those chicks at the end of hatch window at 510 h of incubation. Chick length, chick dry matter content, rectal temperature and weight of small intestine segments increased, whereas chick weight decreased during the hatch window. The increase in the jejunum length and villus width and area during the hatch window were higher for ES3 than ES14 chicks. PepT1 expression was higher for ES3 chicks compared with ES14. There was a 10.2 and 17.6-fold increase in PepT1 and SGLT1 expression of ES3 chicks at the end of hatch window, whereas it was only 2.3 and 3.3-fold, respectively, for ES14 chicks. These results suggested that egg storage duration affected development of early hatched chicks during 30 h of hatch window. It can be concluded that

  19. Nutritional, Biophysical and Physiological Characteristics of Wild Rocket Genotypes As Affected by Soilless Cultivation System, Salinity Level of Nutrient Solution and Growing Period.

    PubMed

    Bonasia, Anna; Lazzizera, Corrado; Elia, Antonio; Conversa, Giulia

    2017-01-01

    With the aim of defining the best management of nutrient solution (NS) in a soilless system for obtaining high quality baby-leaf rocket, the present study focuses on two wild rocket genotypes ("Nature" and "Naturelle"), grown in a greenhouse under two Southern Italy growing conditions-autumn-winter (AW) and winter-spring (WS)-using two soilless cultivation systems (SCS)-at two electrical conductivity values (EC) of NS. The SCSs used were the Floating System (FS) and Ebb and Flow System (EFS) and the EC values were 2.5 and 3.5 dS m(-1) (EC2.5; EC3.5) for the AW cycle and 3.5 and 4.5 dS m(-1) (EC3.5; EC4.5) for the WS cycle. The yield, bio-physical, physiological and nutritional characteristics were evaluated. Higher fresh (FY) (2.25 vs. 1.50 kg m(-2)) and dry (DY) (230.6 vs. 106.1 g m(-2)) weight yield, leaf firmness (dry matter, 104.3 vs. 83.2 g kg(-1) FW; specific leaf area, 34.8 vs. 24.2 g cm(-2)) and antioxidant compounds (vitamin C, 239.0 vs. 152.7 mg kg(-1) FW; total phenols, 997 vs. 450 mg GAE mg kg(-1) FW; total glucosinulates-GLSs, 1,078.8 vs. 405.7 mg kg(-1) DW; total antioxidant capacity-TAC, 11,534 vs. 8,637 μmol eq trolox kg(-1) FW) and lower nitrates (1,470 vs. 3,460 mg kg(-1) FW) were obtained under WS conditions. The seasonal differences were evident on the GLS profile: some aliphatic GLSs (gluconapoleiferin, glucobrassicanapin) and indolic 4-OH-glucobrassicin were only expressed in WS conditions, while indolic glucobrassicin was only detected in the AW period. Compared with EFS, FS improved leaf firmness, visual quality, antioxidant content (TAC, +11.6%) and reduced nitrate leaf accumulation (-37%). "Naturelle" performed better than "Nature" in terms of yield, visual quality and nutritional profile, with differences more evident under less favorable climatic conditions and when the cultivars were grown in FS. Compared to EC2.5, the EC3.5 treatment did not affect DY while enhancing firmness, visual quality, and antioxidant compounds (TAC, +8%), and

  20. Factors Affecting the Delivery, Access, and Use of Interventions to Prevent Malaria in Pregnancy in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

    PubMed Central

    Hill, Jenny; Hoyt, Jenna; van Eijk, Anna Maria; D'Mello-Guyett, Lauren; ter Kuile, Feiko O.; Steketee, Rick; Smith, Helen; Webster, Jayne

    2013-01-01

    Background Malaria in pregnancy has important consequences for mother and baby. Coverage with the World Health Organization–recommended prevention strategy for pregnant women in sub-Saharan Africa of intermittent preventive treatment in pregnancy (IPTp) and insecticide-treated nets (ITNs) is low. We conducted a systematic review to explore factors affecting delivery, access, and use of IPTp and ITNs among healthcare providers and women. Methods and Results We searched the Malaria in Pregnancy Library and Global Health Database from 1 January 1990 to 23 April 2013, without language restriction. Data extraction was performed by two investigators independently, and data was appraised for quality and content. Data on barriers and facilitators, and the effect of interventions, were explored using content analysis and narrative synthesis. We conducted a meta-analysis of determinants of IPTp and ITN uptake using random effects models, and performed subgroup analysis to evaluate consistency across interventions and study populations, countries, and enrolment sites. We did not perform a meta-ethnography of qualitative data. Ninety-eight articles were included, of which 20 were intervention studies. Key barriers to the provision of IPTp and ITNs were unclear policy and guidance on IPTp; general healthcare system issues, such as stockouts and user fees; health facility issues stemming from poor organisation, leading to poor quality of care; poor healthcare provider performance, including confusion over the timing of each IPTp dose; and women's poor antenatal attendance, affecting IPTp uptake. Key determinants of IPTp coverage were education, knowledge about malaria/IPTp, socio-economic status, parity, and number and timing of antenatal clinic visits. Key determinants of ITN coverage were employment status, education, knowledge about malaria/ITNs, age, and marital status. Predictors showed regional variations. Conclusions Delivery of ITNs through antenatal clinics presents

  1. Sodium diformate and extrusion temperature affect nutrient digestibility and physical quality of diets with fish meal and barley protein concentrate for rainbow trout (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of the experiment were to evaluate the effects of ingredient, extrusion temperature, and the acid salt sodium diformate (NaDF) in diets for rainbow trout on apparent nutrient digestibility and physical quality of the diets. The experiment was arranged in a 23 factorial design with two...

  2. An acute decrease in TCA cycle intermediates does not affect aerobic energy delivery in contracting rat skeletal muscle.

    PubMed

    Dawson, Kristen D; Baker, David J; Greenhaff, Paul L; Gibala, Martin J

    2005-06-01

    We tested the hypothesis that an acute decrease in muscle TCA cycle intermediates during contraction would compromise aerobic energy delivery. Male Wistar rats were anaesthetized and the gastrocnemius-plantaris-soleus (GPS) muscle complex from one leg was isolated and perfused with a red cell medium containing either saline (Con) or cycloserine (Cyclo; 0.05 mg g-1), an inhibitor of alanine aminotransferase (AAT). After 1 h of perfusion, the GPS muscle was either snap frozen (Con-Rest, n=11; Cyclo-Rest, n=9) or stimulated to contract for 10 min (1 Hz, 0.3 ms, 2 V) with blood flow fixed at 30 ml min-1 (100 g)-1 and then snap frozen (Con-Stim, n=10; Cyclo-Stim, n=10). Maximal AAT activity was>80% lower (P<0.001) in both Cyclo-treated groups (Rest: 0.61+/-0.02; Stim: 0.63+/-0.01 mmol (kg wet wt)-1 min-1; mean+/-s.e.m.) compared to Con (Rest: 3.56+/-0.16; Stim: 3.92+/-0.29). The sum of five measured TCAI (SigmaTCAI) was reduced by 23% in Cyclo-Rest versus Con-Rest but this was not different (P=0.08). However, after 10 min of contraction, the SigmaTCAI was 25% lower (P=0.006) in Cyclo-Stim compared to Con-Stim (1.88+/-0.15 versus 2.48+/-0.11 mmol (kg dry wt)-1). Despite the acute decrease in TCAI after Cyclo treatment, the contraction-induced changes in markers of non-oxidative energy provision (phosphocreatine, ATP and lactate) and the decline in tension after 10 min of stimulation were similar compared to Con. These data do not support the hypothesis that the total muscle concentration of TCAI is causally linked to the rate of mitochondrial respiration during contraction.

  3. Typhoon-induced precipitation impact on nutrient and suspended matter dynamics of a tropical estuary affected by human activities in Hainan, China

    NASA Astrophysics Data System (ADS)

    Herbeck, Lucia S.; Unger, Daniela; Krumme, Uwe; Liu, Su Mei; Jennerjahn, Tim C.

    2011-07-01

    Typhoons regularly hit the coasts along the northern South China Sea during summer monsoon. However, little is known on the effects of typhoon-related heavy precipitation on estuarine dynamics and coastal ecosystems. We analyzed physico-chemical characteristics, and concentrations and composition of dissolved and suspended matter in the Wenchang/Wenjiao Estuary (WWE) on the tropical island of Hainan, China, prior to and after typhoon Kammuri in August 2008. Before the typhoon, the estuary displayed vertical and horizontal gradients. High nutrient inputs from agriculture and widespread aquaculture were to a large extent converted into biomass inside the estuarine lagoon resulting in low export of nutrients to coastal waters and a mainly autochthonous origin of total suspended matter (TSM). Heavy typhoon-associated precipitation increased river runoff, which moved the location of the estuarine salinity gradient seaward. It resulted in an export of dissolved and particulate matter to coastal waters one day after the typhoon. Dissolved nutrients increased by up to an order of magnitude and TSM increased approximately twofold compared to pre-typhoon values. Lower δ 13C org and δ 15N and elevated C/N ratios of TSM together with lower chlorophyll a (chl a) concentrations indicated an increased contribution of terrestrial material originating from typhoon-induced soil erosion. Local uptake of excess nutrients inside the lagoon was inhibited because of reduced water transparency and the lack of phytoplankton, which had been washed out by the initial freshwater pulse. Two weeks after the typhoon, TSM concentration and composition had almost returned to pre-typhoon conditions. However, physico-chemical properties and nutrients were still different from pre-typhoon conditions indicating that the estuarine system had not fully recovered. Unusually high chl a concentrations in the coastal zone indicated a phytoplankton bloom resulting from the typhoon-induced nutrient export

  4. Factors affecting variation of different measures of cheese yield and milk nutrient recovery from an individual model cheese-manufacturing process.

    PubMed

    Cipolat-Gotet, C; Cecchinato, A; De Marchi, M; Bittante, G

    2013-01-01

    Cheese yield (CY) is the most important technological trait of milk, because cheese-making uses a very high proportion of the milk produced worldwide. Few studies have been carried out at the level of individual milk-producing animals due to a scarcity of appropriate procedures for model-cheese production, the complexity of cheese-making, and the frequent use of the fat and protein (or casein) contents of milk as a proxy for cheese yield. Here, we report a high-throughput cheese manufacturing process that mimics all phases of cheese-making, uses 1.5-L samples of milk from individual animals, and allows the simultaneous processing of 15 samples per run. Milk samples were heated (35°C for 40 min), inoculated with starter culture (90 min), mixed with rennet (51.2 international milk-clotting units/L of milk), and recorded for gelation time. Curds were cut twice (10 and 15 min after gelation), separated from the whey, drained (for 30 min), pressed (3 times, 20 min each, with the wheel turned each time), salted in brine (for 60 min), weighed, and sampled. Whey was collected, weighed, and sampled. Milk, curd, and whey samples were analyzed for pH, total solids, fat content, and protein content, and energy content was estimated. Three measures of percentage cheese yield (%CY) were calculated: %CY(CURD), %CY(SOLIDS), and %CY(WATER), representing the ratios between the weight of fresh curd, the total solids of the curd, and the water content of the curd, respectively, and the weight of the milk processed. In addition, 3 measures of daily cheese yield (dCY, kg/d) were defined, considering the daily milk yield. Three measures of nutrient recovery (REC) were computed: REC(FAT), REC(PROTEIN), and REC(SOLIDS), which represented the ratio between the weights of the fat, protein, and total solids in the curd, respectively, and the corresponding components in the milk. Energy recovery, REC(ENERGY), represented the energy content of the cheese compared with that in the milk. This

  5. Nutritional, Biophysical and Physiological Characteristics of Wild Rocket Genotypes As Affected by Soilless Cultivation System, Salinity Level of Nutrient Solution and Growing Period

    PubMed Central

    Bonasia, Anna; Lazzizera, Corrado; Elia, Antonio; Conversa, Giulia

    2017-01-01

    With the aim of defining the best management of nutrient solution (NS) in a soilless system for obtaining high quality baby-leaf rocket, the present study focuses on two wild rocket genotypes (“Nature” and “Naturelle”), grown in a greenhouse under two Southern Italy growing conditions—autumn-winter (AW) and winter-spring (WS)—using two soilless cultivation systems (SCS)—at two electrical conductivity values (EC) of NS. The SCSs used were the Floating System (FS) and Ebb and Flow System (EFS) and the EC values were 2.5 and 3.5 dS m−1 (EC2.5; EC3.5) for the AW cycle and 3.5 and 4.5 dS m−1 (EC3.5; EC4.5) for the WS cycle. The yield, bio-physical, physiological and nutritional characteristics were evaluated. Higher fresh (FY) (2.25 vs. 1.50 kg m−2) and dry (DY) (230.6 vs. 106.1 g m−2) weight yield, leaf firmness (dry matter, 104.3 vs. 83.2 g kg−1 FW; specific leaf area, 34.8 vs. 24.2 g cm−2) and antioxidant compounds (vitamin C, 239.0 vs. 152.7 mg kg−1 FW; total phenols, 997 vs. 450 mg GAE mg kg−1 FW; total glucosinulates-GLSs, 1,078.8 vs. 405.7 mg kg−1 DW; total antioxidant capacity-TAC, 11,534 vs. 8,637 μmol eq trolox kg−1 FW) and lower nitrates (1,470 vs. 3,460 mg kg−1 FW) were obtained under WS conditions. The seasonal differences were evident on the GLS profile: some aliphatic GLSs (gluconapoleiferin, glucobrassicanapin) and indolic 4-OH-glucobrassicin were only expressed in WS conditions, while indolic glucobrassicin was only detected in the AW period. Compared with EFS, FS improved leaf firmness, visual quality, antioxidant content (TAC, +11.6%) and reduced nitrate leaf accumulation (−37%). “Naturelle” performed better than “Nature” in terms of yield, visual quality and nutritional profile, with differences more evident under less favorable climatic conditions and when the cultivars were grown in FS. Compared to EC2.5, the EC3.5 treatment did not affect DY while enhancing firmness, visual quality, and antioxidant

  6. Nutrient processes at the stream-lake interface for a channelized versus unmodified stream mouth

    USGS Publications Warehouse

    Niswonger, Richard; Naranjo, Ramon C.; Smith, David; Constantz, James E.; Allander, Kip K.; Rosenberry, Donald O.; Neilson, Bethany; Rosen, Michael R.; Stonestrom, David A.

    2017-01-01

    Inorganic forms of nitrogen and phosphorous impact freshwater lakes by stimulating primary production and affecting water quality and ecosystem health. Communities around the world are motivated to sustain and restore freshwater resources and are interested in processes controlling nutrient inputs. We studied the environment where streams flow into lakes, referred to as the stream-lake interface (SLI), for a channelized and unmodified stream outlet. Channelization is done to protect infrastructure or recreational beach areas. We collected hydraulic and nutrient data for surface water and shallow groundwater in two SLIs to develop conceptual models that describe characteristics that are representative of these hydrologic features. Water, heat, and solute transport models were used to evaluate hydrologic conceptualizations and estimate mean residence times of water in the sediment. A nutrient mass balance model is developed to estimate net rates of adsorption and desorption, mineralization, and nitrification along subsurface flow paths. Results indicate that SLIs are dynamic sources of nutrients to lakes and that the common practice of channelizing the stream at the SLI decreases nutrient concentrations in pore water discharging along the lakeshore. This is in contrast to the unmodified SLI that forms a barrier beach that disconnects the stream from the lake and results in higher nutrient concentrations in pore water discharging to the lake. These results are significant because nutrient delivery through pore water seepage at the lakebed from the natural SLI contributes to nearshore algal communities and produces elevated concentrations of inorganic nutrients in the benthic zone where attached algae grow.

  7. Dietary Intake of Nutrients and Lifestyle Affect the Risk of Mild Cognitive Impairment in the Chinese Elderly Population: A Cross-Sectional Study

    PubMed Central

    Lu, Yanhui; An, Yu; Guo, Jin; Zhang, Xiaona; Wang, Hui; Rong, Hongguo; Xiao, Rong

    2016-01-01

    Mild cognitive impairment (MCI) is a pre-clinical stage of Alzheimer’s disease afflicting a large number of the elderly throughout the world. However, modifiable risk factors for the onset and progression of MCI remain unclear. A cross-sectional study was performed to explore whether and how daily dietary nutrients intake and lifestyle impacted the risk of MCI in the Chinese elderly. We examined 2,892 elderly subjects, including 768 MCI patients and 2,124 subjects with normal cognition in three different Provinces of China. Dietary intake of nutrients were collected by using a 33-item food frequency questionnaire and calculated based on the Chinese Food Composition database. The MCI patients were first screened by Montreal Cognitive Assessment and then diagnosed by medical neurologists. Multivariate logistic regression and exploratory factor analyses were applied to identify and rank the risk factors. Three dietary nutrient intake combination patterns were identified as the major protective factors of MCI, with eigenvalues of 14.11, 2.26, and 1.51 and adjusted odds ratios (OR) of 0.77, 0.81, and 0.83 (P < 0.05), respectively. The most protective combination was featured with eight vitamins and six minerals, and OR for the third and fourth quartiles of these nutrients intake ranged from 0.48 to 0.74 (P < 0.05). Carotenoids, vitamin C, and vitamin B6 exhibited the highest protective factor loadings of 0.97, 0.95, and 0.92 (P < 0.05), respectively. Education, computer use, reading, and drinking represented the most protective lifestyle factors (OR = 0.25 to 0.85, P < 0.05), whereas smoking and peripheral vascular diseases were associated with higher (OR = 1.40 and 1.76, P < 0.05) risk of MCI. Adequate dietary intake of monounsaturated fatty acids and cholesterol were significantly associated with decreased risk of MCI. In conclusion, adequate or enhanced intake of micronutrients seemed to lower the risk of MCI in the Chinese elderly. In addition, improving education

  8. Selected nutrient contents, fatty acid composition, including conjugated linoleic acid, and retention values in separable lean from lamb rib loins as affected by external fat and cooking method.

    PubMed

    Badiani, Anna; Montellato, Lara; Bochicchio, Davide; Anfossi, Paola; Zanardi, Emanuela; Maranesi, Magda

    2004-08-11

    Proximate composition and fatty acid profile, conjugated linoleic acid (CLA) isomers included, were determined in separable lean of raw and cooked lamb rib loins. The cooking methods compared, which were also investigated for cooking yields and true nutrient retention values, were dry heating of fat-on cuts and moist heating of fat-off cuts; the latter method was tested as a sort of dietetic approach against the more traditional former type. With significantly (P < 0.05) lower cooking losses, dry heating of fat-on rib-loins produced slightly (although only rarely significantly) higher retention values for all of the nutrients considered, including CLA isomers. On the basis of the retention values obtained, both techniques led to a minimum migration of lipids into the separable lean, which was higher (P < 0.05) in dry heating than in moist heating, and was characterized by the prevalence of saturated and monounsaturated fatty acids. On the whole, the response to cooking of the class of CLA isomers (including that of the nutritionally most important isomer cis-9,trans-11) was more similar to that of the monounsaturated than the polyunsaturated fatty acids.

  9. Arsenic affects mineral nutrients in grains of various Indian rice (Oryza sativa L.) genotypes grown on arsenic-contaminated soils of West Bengal.

    PubMed

    Dwivedi, Sanjay; Tripathi, R D; Srivastava, Sudhakar; Singh, Ragini; Kumar, Amit; Tripathi, Preeti; Dave, Richa; Rai, U N; Chakrabarty, Debasis; Trivedi, P K; Tuli, R; Adhikari, B; Bag, M K

    2010-09-01

    The exposure of paddy fields to arsenic (As) through groundwater irrigation is a serious concern that may not only lead to As accumulation to unacceptable levels but also interfere with mineral nutrients in rice grains. In the present field study, profiling of the mineral nutrients (iron (Fe), phosphorous, zinc, and selenium (Se)) was done in various rice genotypes with respect to As accumulation. A significant genotypic variation was observed in elemental retention on root Fe plaque and their accumulation in various plant parts including grains, specific As uptake (29-167 mg kg(-1) dw), as well as As transfer factor (4-45%). Grains retained the least level of As (0.7-3%) with inorganic As species being the dominant forms, while organic As species, viz., dimethylarsinic acid and monomethylarsonic acid, were non-detectable. In all tested varieties, the level of Se was low (0.05-0.12 mg kg(-1) dw), whereas that of As was high (0.4-1.68 mg kg(-1) dw), considering their safe/recommended daily intake limits, which may not warrant their human consumption. Hence, their utilization may increase the risk of arsenicosis, when grown in As-contaminated areas.

  10. Key Nutrients.

    ERIC Educational Resources Information Center

    Federal Extension Service (USDA), Washington, DC.

    Lessons written to help trainer agents prepare aides for work with families in the Food and Nutrition Program are presented in this booklet. The key nutrients discussed in the 10 lessons are protein, carbohydrates, fat, calcium, iron, iodine, and Vitamins A, B, C, and D. the format of each lesson is as follows: Purpose, Presentation, Application…

  11. Recent (2008-10) water quality in the Barton Springs segment of the Edwards aquifer and its contributing zone, central Texas, with emphasis on factors affecting nutrients and bacteria

    USGS Publications Warehouse

    Mahler, Barbara J.; Musgrove, MaryLynn; Sample, Thomas L.; Wong, Corinne I.

    2011-01-01

    The Barton Springs zone, which comprises the Barton Springs segment of the Edwards aquifer and the watersheds to the west that contribute to its recharge, is in south-central Texas, an area with rapid growth in population and increasing amounts of land area affected by development. During November 2008-March 2010, an investigation of factors affecting the fate and transport of nutrients and bacteria in the Barton Springs zone was conducted by the U.S. Geological Survey (USGS), in cooperation with the Texas Commission on Environmental Quality. The primary objectives of the study were to characterize occurrence of nutrients and bacteria in the Barton Springs zone under a range of flow conditions; to improve understanding of the interaction between surface-water quality and groundwater quality; and to evaluate how factors such as streamflow variability and dilution affect the fate and transport of nutrients and bacteria in the Barton Springs zone. The USGS collected and analyzed water samples from five streams (Barton, Williamson, Slaughter, Bear, and Onion Creeks), two groundwater wells (Marbridge and Buda), and the main orifice of Barton Springs in Austin, Texas. During the period of the study, during which the hydrologic conditions transitioned from exceptional drought to wetter than normal, water samples were collected routinely (every 3 to 4 weeks) from the streams, wells, and spring and, in response to storms, from the streams and spring. All samples were analyzed for major ions, nutrients, the bacterium Escherichia coli, and suspended sediment. During the dry period, the geochemistry of groundwater at the two wells and at Barton Springs was dominated by flow from the aquifer matrix and was relatively similar and unchanging at the three sites. At the onset of the wet period, when the streams began to flow, the geochemistry of groundwater samples from the Marbridge well and Barton Springs changed rapidly, and concentrations of most major ions and nutrients and

  12. Out of sight - Profiling soil characteristics, nutrients and microbial communities affected by organic amendments down to one meter in a long-term maize cultivation experiment

    NASA Astrophysics Data System (ADS)

    Lehtinen, Taru; Mikkonen, Anu; Zavattaro, Laura; Grignani, Carlo; Baumgarten, Andreas; Spiegel, Heide

    2016-04-01

    Soil characteristics, nutrients and microbial activity in the deeper soil layers are topics not of-ten covered in agricultural studies since the main interest lies within the most active topsoils and deep soils are more time-consuming to sample. Studies have shown that deep soil does matter, although biogeochemical cycles are not fully understood yet. The main aim of this study is to investigate the soil organic matter dynamics, nutrients and microbial community composition in the first meter of the soil profiles in the long-term maize cropping system ex-periment Tetto Frati, in the vicinity of the Po River in Northern Italy. The trial site lies on a deep, calcareous, free-draining soil with a loamy texture. The following treatments have been applied since 1992: 1) maize for silage with 250 kg mineral N ha-1 (crop residue removal, CRR), 2) maize for grain with 250 kg mineral N ha-1 (crop residue incorporation, CRI), 3) maize for silage with 250 kg bovine slurry N ha-1 (SLU), 4) maize for silage with 250 kg farm yard manure N ha-1 (FYM). Soil characteristics (pH, carbonate content, soil organic carbon (SOC), aggregate stability (WSA)), and nutrients (total nitrogen (Nt), CAL-extractable phos-phorous (P) and potassium (K), potential N mineralisation) were investigated. Bacteri-al community composition was investigated with Ion PGM high-throughput sequencing at the depth of 8000 sequences per sample. Soil pH was moderately alkaline in all soil samples, in-creasing with increasing soil depth, as the carbonate content increased. SOC was significantly higher in the treatments with organic amendments (CRI, SLU and FYM) compared to CRR in 0-25 cm (11.1, 11.6, 14.7 vs. 9.8 g kg-1, respectively), but not in the deeper soil. At 50-75 cm soil depth FYM treatment revealed higher WSA compared to CRR, as well as higher CAL-extractable K (25 and 15 mg kg-1, respectively) and potential N mineralisation (11.30 and 8.78 mg N kg-1 7d-1, respectively). At 75-100 cm soil depth, SLU and

  13. Small-scale soil water repellency in pine rizhosphere associated with ectomycorrhiza is affected by nutrient patchiness: a soil microcosms study

    NASA Astrophysics Data System (ADS)

    Lozano, Elena; Hallett, Paul; Johnson, David; Moore, Lucy; Mataix-Solera, Jorge; Jiménez-Pinilla, Patricia; Arcenegui, Victoria

    2014-05-01

    Soil water repellency (SWR) or hydrophobicity has been commonly related to organic compounds released from the roots or decomposition of different plant species (Doerr et al., 2000). In addition, fungi and microorganisms that are associated with specific plants, could also influence SWR through the production of exudates or cellular material that form hydrophobic coatings on soil surfaces (Feeney et al., 2004; Hallett and Young, 1999) or act as surfactants. Nutrient availability, microbial biomass, organic matter and specific exudates have all been associated with the development of SWR. In terms of plant productivity, these impacts can be significant as their interaction with pore structure changes at the root-soil interface regulates both water transport and storage (Sperry et al., 1998). In boreal forests, basidiomycetous fungi are known to have a large impact on the development of SWR. These fungi are important degraders of organic material and symbionts forming ectomycorrhizal fungi (EF) associations with trees. Although many researchers have suggested a strong positive impact of EF on the ability of plants to capture water from soils, their impact on SWR at the root-soil interface and spatially within soil with a patchy nutrient distribution has not yet been investigated. This study used microcosms with mycelia systems of the EF extending from Pinus sylvestris host plants. Each microcosm was incubated during 15 days and contained plastic cup with 33P under the roots. The transfer of P from the mycelium to the host plant was monitored using a radioactive tracers and a non-destructive electronic autoradiography system in another study (data not published). SWR was measured using different approaches; as repellency index, R using a microinfiltrometer with a contact radius of 0.1 mm (modified from Hallet et al., 2002) and with the water drop penetration time test (WDPT). Sorptivity and SWR were measured between 40-50 points/microcosms. Results obtained with both

  14. Dissolved Nutrient Retention Dynamics in River Networks: A Modeling Investigation of Transient Flow and Scale Effects

    SciTech Connect

    Ye, Sheng; Covino, Timothy P.; Sivapalan, Murugesu; Basu, Nandita; Li, Hongyi; Wang, Shaowen

    2012-06-30

    In this paper, we use a dynamic network flow model, coupled with a transient storage zone biogeochemical model, to simulate dissolved nutrient removal processes at the channel network scale. We have explored several scenarios in respect of the combination of rainfall variability, and the biological and geomorphic characteristics of the catchment, to understand the dominant controls on removal and delivery of dissolved nutrients (e.g., nitrate). These model-based theoretical analyses suggested that while nutrient removal efficiency is lower during flood events compared to during baseflow periods, flood events contribute significantly to bulk nutrient removal, whereas bulk removal during baseflow periods is less. This is due to the fact that nutrient supply is larger during flood events; this trend is even stronger in large rivers. However, the efficiency of removal during both periods decreases in larger rivers, however, due to (i) increasing flow velocities and thus decreasing residence time, and (ii) increasing flow depth, and thus decreasing nutrient uptake rates. Besides nutrient removal processes can be divided into two parts: in the main channel and in the hyporheic transient storage zone. When assessing their relative contributions the size of the transient storage zone is a dominant control, followed by uptake rates in the main channel and in the transient storage zone. Increasing size of the transient storage zone with downstream distance affects the relative contributions to nutrient removal of the water column and the transient storage zone, which also impacts the way nutrient removal rates scale with increasing size of rivers. Intra-annual hydrologic variability has a significant impact on removal rates at all scales: the more variable the streamflow is, compared to mean discharge, the less nutrient is removed in the channel network. A scale-independent first order uptake coefficient, ke, estimated from model simulations, is highly dependent on the

  15. Richness, biomass, and nutrient content of a wetland macrophyte community affect soil nitrogen cycling in a diversity-ecosystem functioning experiment

    USGS Publications Warehouse

    Korol, Alicia R.; Ahn, Changwoo; Noe, Gregory

    2016-01-01

    The development of soil nitrogen (N) cycling in created wetlands promotes the maturation of multiple biogeochemical cycles necessary for ecosystem functioning. This development proceeds from gradual changes in soil physicochemical properties and influential characteristics of the plant community, such as competitive behavior, phenology, productivity, and nutrient composition. In the context of a 2-year diversity experiment in freshwater mesocosms (0, 1, 2, 3, or 4 richness levels), we assessed the direct and indirect impacts of three plant community characteristics – species richness, total biomass, and tissue N concentration – on three processes in the soil N cycle – soil net ammonification, net nitrification, and denitrification potentials. Species richness had a positive effect on net ammonification potential (NAP) through higher redox potentials and likely faster microbial respiration. All NAP rates were negative, however, due to immobilization and high rates of ammonium removal. Net nitrification was inhibited at higher species richness without mediation from the measured soil properties. Higher species richness also inhibited denitrification potential through increased redox potential and decreased nitrification. Both lower biomass and/or higher tissue ratios of carbon to nitrogen, characteristics indicative of the two annual plants, were shown to have stimulatory effects on all three soil N processes. The two mediating physicochemical links between the young macrophyte community and microbial N processes were soil redox potential and temperature. Our results suggest that early-successional annual plant communities play an important role in the development of ecosystem N multifunctionality in newly created wetland soils.

  16. Molecular Analysis of a Genetic Variants Panel Related to Nutrients and Metabolism: Association with Susceptibility to Gestational Diabetes and Cardiometabolic Risk in Affected Women

    PubMed Central

    Nicolucci, Antonio; Celentano, Claudio; Liberati, Marco; Stuppia, Liborio

    2017-01-01

    Gestational diabetes mellitus (GDM) is the most frequent metabolic disorder in pregnancy. Women with a GDM history are at increased risk of developing diabetes and cardiovascular diseases. Studies have demonstrated a significant correlation between several genes involved in the metabolic pathway of insulin and environmental factors. The aim of this study was to investigate the relationship between clinical parameters in GDM and variants in genes involved with nutrients and metabolism. Several variants PPARG2 rs1801282 (C>G); PPARGC1A rs8192678 (C>T); TCF7L2 rs7903146 (C>T); LDLR rs2228671 (C>T); MTHFR rs1801133 (C>T); APOA5 rs662799 (T>C); GCKR rs1260326 (C>T); FTO rs9939609 (T>A); MC4R rs17782313 (T>C) were genotyped in 168 pregnant Caucasian women with or without GDM by High Resolution Melting (HRM) analysis. A significant correlation was observed between TT genotype of TCF7L2 gene and increased risk of GDM (OR 5.4 [95% CI 1.5–19.3]). Moreover, a significant correlation was observed between lipid parameters and genetic variations in additional genes, namely, PPARG2 [p = 0,02], APOA5 [p = 0,02], MC4R [p = 0,03], LDLR [p = 0,01], and FTO [p = 0,02]. Our findings support the association between TCF7L2 rs7903146 variant and an increased GDM risk. Results about the investigated genetic variants provide important information about cardiometabolic risk in GDM and help to plan future prevention studies. PMID:28133617

  17. The yeast production system in which Escherichia coli phytase is expressed may affect growth performance, bone ash, and nutrient use in broiler chicks.

    PubMed

    Onyango, E M; Bedford, M R; Adeola, O

    2004-03-01

    The efficacy of three Escherichia coli-derived phytase preparations on the performance and nutrient utilization of broiler chicks was evaluated. Two hundred sixteen 7-d-old male broiler chicks were grouped by weight into 6 blocks of 6 cages with 6 birds per cage. Six corn-soybean meal-based diets were randomly assigned to cages within each block. The 6 diets were adequate P, very low P, and low P and contained (g of P/kg of diet) 7.7, 4.0, and 5.1, respectively; and low-P diet plus phytase preparation A, B, or C at 1,000 units/kg of feed. All 3 phytase preparations were produced in different yeast production systems with slightly different glycosylation patterns. Preparation A was produced in Pichia pastoris, B in Schizosaccharomyces pombe, and C in Saccharomyces cerevisiae. The chicks were fed the experimental diets from 8 to 22 d of age. Excreta samples were collected between 17 and 21 d of age. At the end of the study, blood was collected, chicks were killed, and tibiae were removed from 3 birds per cage. Weight gain, feed intake, and feed efficiency among the 3 phytase preparations did not differ, although only phytase A diet outperformed (P < 0.05) the low-P diet in terms of weight gain and feed efficiency. All 3 phytase diets outperformed (P < 0.05) the low-P diet in bone mineral content, density, strength, percentage ash, P retention, and serum P levels. Phytase B diet outperformed the adequate-P diet in bone strength. All 3 preparations increased (P < 0.05) Ca retention with phytase B or C showing a better retention of Ca than phytase A. All 3 phytase preparations showed similar P use as indicated by BW gain and tibia bone characteristics.

  18. Phytosiderophore release by wheat genotypes differing in zinc deficiency tolerance grown with Zn-free nutrient solution as affected by salinity.

    PubMed

    Daneshbakhsh, Bahareh; Khoshgoftarmanesh, Amir Hossein; Shariatmadari, Hossein; Cakmak, Ismail

    2013-01-01

    There is limited information concerning the effect of salinity on phytosiderophores exudation from wheat roots. The aim of this hydroponic experiment was to investigate the effect of salinity on phytosiderophore release by roots of three bread wheat genotypes differing in Zn efficiency (Triticum aestivum L. cvs. Rushan, Kavir, and Cross) under Zn deficiency conditions. Wheat seedlings were transferred to Zn-free nutrient solutions and exposed to three salinity levels (0, 60, and 120 mM NaCl). The results indicated that Cross and Rushan genotypes exuded more phytosiderophore than did the Kavir genotype. Our findings suggest that the adaptive capacity of Zn-efficient 'Cross' and 'Rushan' wheat genotypes to Zn deficiency is due partly to the higher amounts of phytosiderophore release. Only 15 days of Zn deficiency stress was sufficient to distinguish between Zn-efficient (Rushan and Cross) and Zn-inefficient (Kavir) genotypes, with the former genotypes exuding more phytosiderophore than the latter. Higher phytosiderophore exudation under Zn deficiency conditions was accompanied by greater Fe transport from root to shoot. The maximum amount of phytosiderophore was exuded at the third week in 'Cross' and at the fourth week in 'Kavir' and 'Rushan'. For all three wheat genotypes, salinity stress resulted in higher amounts of phytosiderophore exuded by the roots. In general, for 'Kavir', the largest amount of phytosiderophore was exuded from the roots at the highest salinity level (120mM NaCl), while for 'Cross' and 'Rushan', no significant difference was found in phytosiderophore exudation between the 60 and 120 mM NaCl treatments. More investigation is needed to fully understand the physiology of elevated phytosiderophore release by Zn-deficient wheat plants under salinity conditions.

  19. Bone nutrients for vegetarians.

    PubMed

    Mangels, Ann Reed

    2014-07-01

    The process of bone mineralization and resorption is complex and is affected by numerous factors, including dietary constituents. Although some dietary factors involved in bone health, such as calcium and vitamin D, are typically associated with dairy products, plant-based sources of these nutrients also supply other key nutrients involved in bone maintenance. Some research suggests that vegetarian diets, especially vegan diets, are associated with lower bone mineral density (BMD), but this does not appear to be clinically significant. Vegan diets are not associated with an increased fracture risk if calcium intake is adequate. Dietary factors in plant-based diets that support the development and maintenance of bone mass include calcium, vitamin D, protein, potassium, and soy isoflavones. Other factors present in plant-based diets such as oxalic acid and phytic acid can potentially interfere with absorption and retention of calcium and thereby have a negative effect on BMD. Impaired vitamin B-12 status also negatively affects BMD. The role of protein in calcium balance is multifaceted. Overall, calcium and protein intakes in accord with Dietary Reference Intakes are recommended for vegetarians, including vegans. Fortified foods are often helpful in meeting recommendations for calcium and vitamin D. Plant-based diets can provide adequate amounts of key nutrients for bone health.

  20. Sexual competition affects biomass partitioning, carbon-nutrient balance, Cd allocation and ultrastructure of Populus cathayana females and males exposed to Cd stress.

    PubMed

    Chen, Juan; Duan, Baoli; Xu, Gang; Korpelainen, Helena; Niinemets, Ülo; Li, Chunyang

    2016-11-01

    Although increasing attention has been paid to plant adaptation to soil heavy metal contamination, competition and neighbor effects have been largely overlooked, especially in dioecious plants. In this study, we investigated growth as well as biochemical and ultrastructural responses of Populus cathayana Rehder females and males to cadmium (Cd) stress under different sexual competition patterns. The results showed that competition significantly affects biomass partitioning, photosynthetic capacity, leaf and root ultrastructure, Cd accumulation, the contents of polyphenols, and structural and nonstructural carbohydrates. Compared with single-sex cultivation, plants of opposite sexes exposed to sexual competition accumulated more Cd in tissues and their growth was more strongly inhibited, indicating enhanced Cd toxicity under sexual competition. Under intrasexual competition, females showed greater Cd accumulation, more serious damage at the ultrastructural level and greater reduction in physiological activity than under intersexual competition, while males performed better under intrasexual competition than under intersexual competition. Males improved the female microenvironment by greater Cd uptake and lower resource consumption under intersexual competition. These results demonstrate that the sex of neighbor plants and competition affect sexual differences in growth and in key physiological processes under Cd stress. The asymmetry of sexual competition highlighted here might regulate population structure, and spatial segregation and phytoremediation potential of both sexes in P. cathayana growing in heavy metal-contaminated soils.

  1. Nutrient absorption.

    PubMed

    Rubin, Deborah C

    2004-03-01

    Our understanding of nutrient absorption continues to grow, from the development of unique animal models and from studies in which cutting-edge molecular and cellular biologic approaches have been used to analyze the structure and function of relevant molecules. Studies of the molecular genetics of inherited disorders have also provided many new insights into these processes. A major advance in lipid absorption has been the cloning and characterization of several intestinal acyl CoA:monoacylglycerol acyltransferases; these may provide new targets for antiobesity drug therapy. Studies of intestinal cholesterol absorption and reverse cholesterol transport have encouraged the development of novel potential treatments for hyperlipidemia. Observations in genetically modified mice and in humans with mutations in glucose transporter 2 suggest the importance of a separate microsomal membrane transport pathway for glucose transport. The study of iron metabolism has advanced greatly with the identification of the hemochromatosis gene and the continued examination of the genetic regulation of iron absorptive pathways. Several human thiamine transporters have been identified, and their specific roles in different tissues are being explored.

  2. Nutrients in the nexus

    USGS Publications Warehouse

    Davidson, Eric A.; Niphong, Rachel; Ferguson, Richard B.; Palm, Cheryl; Osmond, Deanna L.; Baron, Jill S.

    2016-01-01

    Synthetic nitrogen (N) fertilizer has enabled modern agriculture to greatly improve human nutrition during the twentieth century, but it has also created unintended human health and environmental pollution challenges for the twenty-first century. Averaged globally, about half of the fertilizer-N applied to farms is removed with the crops, while the other half remains in the soil or is lost from farmers’ fields, resulting in water and air pollution. As human population continues to grow and food security improves in the developing world, the dual development goals of producing more nutritious food with low pollution will require both technological and socio-economic innovations in agriculture. Two case studies presented here, one in sub-Saharan Africa and the other in Midwestern United States, demonstrate how management of nutrients, water, and energy is inextricably linked in both small-scale and large-scale food production, and that science-based solutions to improve the efficiency of nutrient use can optimize food production while minimizing pollution. To achieve the needed large increases in nutrient use efficiency, however, technological developments must be accompanied by policies that recognize the complex economic and social factors affecting farmer decision-making and national policy priorities. Farmers need access to affordable nutrient supplies and support information, and the costs of improving efficiencies and avoiding pollution may need to be shared by society through innovative policies. Success will require interdisciplinary partnerships across public and private sectors, including farmers, private sector crop advisors, commodity supply chains, government agencies, university research and extension, and consumers.

  3. Assessing the effects of nutrient management in an estuary experiencing climatic change: the Neuse River Estuary, North Carolina.

    PubMed

    Paerl, Hans W; Valdes, Lexia M; Piehler, Michael F; Stow, Craig A

    2006-03-01

    Eutrophication is a serious water quality problem in estuaries receiving increasing anthropogenic nutrient loads. Managers undertaking nutrient-reduction strategies aimed at controlling estuarine eutrophication are faced with the challenge that upstream freshwater segments often are phosphorus (P)-limited, whereas more saline downstream segments are nitrogen (N)-limited. Management also must consider climatic (hydrologic) variability, which affects nutrient delivery and processing. The interactive effects of selective nutrient input reductions and climatic perturbations were examined in the Neuse River Estuary (NRE), North Carolina, a shallow estuary with more than a 30-year history of accelerated nutrient loading and water quality decline. The NRE also has experienced a recent increase in Atlantic hurricanes and record flooding, which has affected hydrology and nutrient loadings. The authors examined the water quality consequences of selective nutrient (P but not N) reductions in the 1980s, followed by N reductions in the 1990s and an increase in hurricane frequency since the mid-1990s. Selective P reductions decreased upstream phytoplankton blooms, but increased downstream phytoplankton biomass. Storms modified these trends. In particular, upstream annual N and P concentrations have decreased during the elevated hurricane period. Increased flushing and scouring from storms and flooding appear to have enhanced nutrient retention capabilities of the NRE watershed. From a management perspective, one cannot rely on largely unpredictable changes in storm frequency and intensity to negate anthropogenic nutrient enrichment and eutrophication. To control eutrophication along the hydrologically variable freshwater-marine continuum, N and P reductions should be applied adaptively to reflect point-source-dominated drought and non-point-source-dominated flood conditions.

  4. NUTRIENT DYNAMICS IN RELATION TO GEOMORPHOLOGY OF RIVERINE WETLANDS

    EPA Science Inventory

    Variation in water depth and soil properties associated with geomorphic structures can affect riverine wetland nutrient dynamics by altering biogeochemical processes. We examined the seasonal influence of soils and geomorphology on nutrient forms and concentrations in riverine we...

  5. Application of a calibrated/validated Agricultural Policy/Environmental eXtender model to assess sediment and nutrient delivery from the Wildcat Creek Mississippi River Basin Initiative – Cooperative Conservation Partnership

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Wildcat Creek, a tributary to the Wabash River was identified by the USDA Natural Resources Conservation Service (NRCS) as a priority watershed for its high sediment and nutrient loading contributions to the Mississippi River. As part of the Mississippi River Basin Initiative (MRBI), the incorpo...

  6. Rhizosphere priming: a nutrient perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizosphere priming is the change in decomposition of soil organic matter (SOM) caused by root activity. Rhizosphere priming plays a crucial role in soil carbon (C) dynamics and their response to global climate change. Rhizosphere priming may be affected by soil nutrient availability, but rhizospher...

  7. Regulating nutrient allocation in plants

    DOEpatents

    Udvardi, Michael; Yang, Jiading; Worley, Eric

    2014-12-09

    The invention provides coding and promoter sequences for a VS-1 and AP-2 gene, which affects the developmental process of senescence in plants. Vectors, transgenic plants, seeds, and host cells comprising heterologous VS-1 and AP-2 genes are also provided. Additionally provided are methods of altering nutrient allocation and composition in a plant using the VS-1 and AP-2 genes.

  8. How does outcome-based funding affect service delivery? An analysis of consequences within employment services for people living with serious mental illness.

    PubMed

    Gewurtz, Rebecca E; Cott, Cheryl; Rush, Brian; Kirsh, Bonnie

    2015-01-01

    This paper explores the impact of outcome-based funding on service delivery within employment services for people with serious mental illness. It draws on a case study of a policy change in the provincial disability support program in Ontario, Canada where funding for employment programs and services was changed from a fee-for-service to an outcome-based model. The findings highlight that the financial imperative for programs to meet employment targets in order to secure their funding has shifted the focus away from the provision of pre-employment supports to job development and job placements. However, there remains little attention to job matching and career development, and there is concern about access to services among those with complex barriers to employment. There is a need to reconcile tensions between the goals of outcome-based funding and on-the-ground service delivery to promote ongoing innovation in employment services for people with serious mental illness.

  9. Trends affecting the future of vaccine development and delivery: The role of demographics, regulatory science, the anti-vaccine movement, and vaccinomics

    PubMed Central

    Poland, Gregory A.; Jacobson, Robert M.; Ovsyannikova, Inna G.

    2009-01-01

    Important scientific, cultural, temporal, and secular issues impact the development of, and delivery of vaccines. In this paper we discuss the impact of demographics, regulatory science, the anti-vaccine movement, and finally the impact of the new biology and individualized medicine, which we call vaccinomics, on vaccine development and delivery. A description of the issues and how they have, are, or should be impacting vaccinology is provided, and hopefully will result in increased attention and discussion among vaccinologists. These issues have been under-valued, under-discussed, and in some cases, ignored. We hope that discussion of these issues will result in changes in how we develop, and how we communicate those developments, to the public. PMID:19200833

  10. Design of calcium phosphate ceramics for drug delivery applications in bone diseases: A review of the parameters affecting the loading and release of the therapeutic substance.

    PubMed

    Parent, Marianne; Baradari, Hiva; Champion, Eric; Damia, Chantal; Viana-Trecant, Marylène

    2017-02-21

    Effective treatment of critical-size defects is a key challenge in restorative surgery of bone. The strategy covers the implantation of biocompatible, osteoconductive, bioactive and biodegradable devices which (1) well interact with native tissue, mimic multi-dimensional and hierarchical structure of bone and (2) are able to enhance bone repair, treating post implantation pathologies or bone diseases by local delivery of therapeutic agents. Among different options, calcium phosphate biomaterials are found to be attractive choices, due to their excellent biocompatibility, customisable bioactivity and biodegradability. Several approaches have been established to enhance this material ability to be loaded with a therapeutic agent, in order to obtain an in situ controlled release that meets the clinical needs. This article reviews the most important factors influencing on both drug loading and release capacity of porous calcium phosphate bone substitutes. Characteristics of the carrier, drug/carrier interactions, experimental conditions of drug loading and evaluation of drug delivery are considered successively.

  11. Measuring and decomposing socioeconomic inequality in healthcare delivery: A microsimulation approach with application to the Palestinian conflict-affected fragile setting.

    PubMed

    Abu-Zaineh, Mohammad; Mataria, Awad; Moatti, Jean-Paul; Ventelou, Bruno

    2011-01-01

    Socioeconomic-related inequalities in healthcare delivery have been extensively studied in developed countries, using standard linear models of decomposition. This paper seeks to assess equity in healthcare delivery in the particular context of the occupied Palestinian territory: the West Bank and the Gaza Strip, using a new method of decomposition based on microsimulations. Besides avoiding the 'unavoidable price' of linearity restriction that is imposed by the standard methods of decomposition, the microsimulation-based decomposition enables to circumvent the potentially contentious role of heterogeneity in behaviours and to better disentangle the various sources driving inequality in healthcare utilisation. Results suggest that the worse-off do have a disproportinately greater need for all levels of care. However with the exception of primary-level, utilisation of all levels of care appears to be significantly higher for the better-off. The microsimulation method has made it possible to identify the contributions of factors driving such pro-rich patterns. While much of the inequality in utilisation appears to be caused by the prevailing socioeconomic inequalities, detailed analysis attributes a non-trivial part (circa 30% of inequalities) to heterogeneity in healthcare-seeking behaviours across socioeconomic groups of the population. Several policy recommendations for improving equity in healthcare delivery in the occupied Palestinian territory are proposed.

  12. Modelling the Danube-influenced North-western Continental Shelf of the Black Sea. II: Ecosystem Response to Changes in Nutrient Delivery by the Danube River after its Damming in 1972

    NASA Astrophysics Data System (ADS)

    Lancelot, C.; Staneva, J.; van Eeckhout, D.; Beckers, J.-M.; Stanev, E.

    2002-03-01

    The ecological model BIOGEN, describing the carbon, nitrogen, phosphorus and silicon cycling throughout aggregated chemical and biological compartments of the planktonic and benthic marine systems, has been implemented in the north-western Black Sea to assess the response of this coastal ecosystem to eutrophication by the Danube River. The trophic resolution of BIOGEN was chosen to simulate the major ecological changes reported in this coastal area since the 1960s. Particular attention was paid to establishing the link between quantitative and qualitative changes in nutrients, phytoplankton composition and food-web structures. The BIOGEN numerical code structure includes 34 state variables assembled in five interactive modules describing the dynamics of (1) phytoplankton composed of three distinct groups, each with a different trophic fate (diatoms, nanophytoflagellates, non-silicified opportunistic species); (2) meso- and microzooplankton; (3) trophic dead-end gelatinous organisms composed of three distinct groups (the omnivorous Noctiluca and the carnivores Aurelia and the alien Mnemiopsis ), and organic matter degradation and associated nutrient regeneration processes by (4) planktonic and (5) benthic bacteria. The capability of the BIOGEN model to simulate the recent ecosystem changes reported for the Black Sea was demonstrated by running the model for the period 1985-1995. The BIOGEN code was implemented in an aggregated and simplified representation of the north-western Black Sea hydrodynamics. The numerical frame consisted of coupling a 0-D BIOGEN box model subjected to the Danube with a 1-D BIOGEN representing the open-sea boundary conditions. Model results clearly showed that the eutrophication-related problems of the north-western Black Sea were not only driven by the quantity of nutrients discharged by the Danube, but that the balance between them was also important. BIOGEN simulations clearly demonstrated that phosphate, rather than silicate, was the

  13. Root Nutrient Foraging1

    PubMed Central

    Giehl, Ricardo F.H.; von Wirén, Nicolaus

    2014-01-01

    During a plant's lifecycle, the availability of nutrients in the soil is mostly heterogeneous in space and time. Plants are able to adapt to nutrient shortage or localized nutrient availability by altering their root system architecture to efficiently explore soil zones containing the limited nutrient. It has been shown that the deficiency of different nutrients induces root architectural and morphological changes that are, at least to some extent, nutrient specific. Here, we highlight what is known about the importance of individual root system components for nutrient acquisition and how developmental and physiological responses can be coupled to increase nutrient foraging by roots. In addition, we review prominent molecular mechanisms involved in altering the root system in response to local nutrient availability or to the plant's nutritional status. PMID:25082891

  14. Root nutrient foraging.

    PubMed

    Giehl, Ricardo F H; von Wirén, Nicolaus

    2014-10-01

    During a plant's lifecycle, the availability of nutrients in the soil is mostly heterogeneous in space and time. Plants are able to adapt to nutrient shortage or localized nutrient availability by altering their root system architecture to efficiently explore soil zones containing the limited nutrient. It has been shown that the deficiency of different nutrients induces root architectural and morphological changes that are, at least to some extent, nutrient specific. Here, we highlight what is known about the importance of individual root system components for nutrient acquisition and how developmental and physiological responses can be coupled to increase nutrient foraging by roots. In addition, we review prominent molecular mechanisms involved in altering the root system in response to local nutrient availability or to the plant's nutritional status.

  15. Nutrient export from watersheds on Mt. Desert Island, Maine, as a function of land use and fire history.

    PubMed

    Nielsen, Martha G; Kahl, Jeffrey S

    2007-03-01

    A study of 13 small (less than 7.5 km(2)) watersheds on Mt. Desert Island, Maine, was conducted from January 1999 to September 2000 to determine nutrient export delivery to coastal waters around the island, and to determine whether a series of wildfires in 1947 have affected nutrient export in burned watersheds. Nutrient export (nitrate-nitrogen, total nitrogen, total phosphorus) was determined for each watershed during the study period, and was normalized by watershed area. The yield of nitrate-nitrogen (N) ranged from 10 to 140 kg/km(2)/year. Total N yield ranged from 42 to 250 kg/km(2)/year. Total phosphorus (P) yield ranged from 1.4 to 7.9 kg/km(2)/year. Watersheds entirely within Acadia National Park (lacking human land-based nutrient sources) exported significantly less total N and total P than watersheds that were partly or entirely outside the park boundary. Nitrate-N export was not significantly different in these two groups of watersheds, perhaps because atmospheric deposition is a dominant source of nitrate in the study area. No relation was observed between burn history and nutrient export. Any effect of burn history may be masked by other landscape-level factors related to nutrient export.

  16. Nutrient export from watersheds on Mt. Desert Island, maine, as a function of land use and fire history

    USGS Publications Warehouse

    Nielsen, M.G.; Kahl, J.S.

    2007-01-01

    A study of 13 small (less than 7.5 km2) watersheds on Mt. Desert Island, Maine, was conducted from January 1999 to September 2000 to determine nutrient export delivery to coastal waters around the island, and to determine whether a series of wildfires in 1947 have affected nutrient export in burned watersheds. Nutrient export (nitrate-nitrogen, total nitrogen, total phosphorus) was determined for each watershed during the study period, and was normalized by watershed area. The yield of nitrate-nitrogen (N) ranged from 10 to 140 kg/km2/year. Total N yield ranged from 42 to 250 kg/ km2/year. Total phosphorus (P) yield ranged from 1.4 to 7.9 kg/km2/year. Watersheds entirely within Acadia National Park (lacking human land-based nutrient sources) exported significantly less total N and total P than watersheds that were partly or entirely outside the park boundary. Nitrate-N export was not significantly different in these two groups of watersheds, perhaps because atmospheric deposition is a dominant source of nitrate in the study area. No relation was observed between burn history and nutrient export. Any effect of burn history may be masked by other landscape-level factors related to nutrient export. ?? Springer Science + Business Media B.V. 2007.

  17. A System for Managing Replenishment of a Nutrient Solution Using an Electrical Conductivity Controller

    NASA Technical Reports Server (NTRS)

    Davis, D.; Dogan, N.; Aglan, H.; Mortley, D.; Loretan, P.

    1998-01-01

    Control of nutrient solution parameters is very important for the growth and development of plants grown hydroponically. Protocols involving different nutrient solution replenishment times (e.g. one-week, two-week, or two-day replenishment) provide manual periodic control of the nutrient solution's electrical conductivity (EC). Since plants take-up nutrients as they grow, manual control has a drawback in that EC is not held constant between replenishments. In an effort to correct this problem the Center for Food and Environmental Systems for Human Exploration of Space at Tuskegee University has developed a system for managing and controlling levels of EC over a plant's entire growing cycle. A prototype system is being tested on sweetpotato production using the nutrient film technique (NFT), and it is being compared to a system in which sweetpotatoes are grown using NFT with manual control. NASA has played an important role in the development of environmental control systems. They have become a forerunner in growing plants hydroponically with some control systems through the use of networked data acquisition and control using environmental growth chambers. Data acquisition systems which involve the use of real-time, calibration, set points, user panel, and graphical representation programming provide a good method of controlling nutrient solution parameters such as EC and pH [Bledsoe, 19931]. In NASA's Biomass Production Chamber (BPC) at Kennedy Space Center, control is provided by a programmable logic controller (PLC). This is an industrial controller which combines ladder computer logic which has the ability to handle various levels of electrical power. The controller controls temperature, light and other parameters that affect the plant's environment, in the BPC, the Nutrient Delivery System (NIX), a sub-system of the PLC, controls nutrient solution parameters such as EC, pH, and solution levels. When the nutrient EC measurement goes outside a preset range (120

  18. Nutrient insult in early pregnancy.

    PubMed

    Coad, Jane; Al-Rasasi, Buthaina; Morgan, Jane

    2002-02-01

    Nutrient insults in early pregnancy, such as nutrient deprivation during famines, are often associated with an unfavourable outcome. Suboptimal nutrition in the early stage of gestation has been linked to a number of adverse effects on fetal growth and development. Historically, nausea and vomiting in pregnancy (NVP) was an important contributor to pregnancy-related mortality; indeed, Charlotte Bronte died from starvation and dehydration after suffering very severe NVP 4 months into her first pregnancy (Gaskell, 1858). Although NVP seldom now progresses to be life-threatening, it affects the majority of pregnant women, and potentially presents a challenge to nutrient intake in the most vulnerable period of development. Symptoms range from mild (nausea only) to severe (a level of vomiting that restricts nutrient intake and ultimately threatens metabolic and electrolyte balance). Although NVP has been documented for thousands of years, its cause has not yet been satisfactorily elucidated, but seems to be related to endocrinological changes. Pregnant women also frequently report dietary cravings and aversions during pregnancy which can be linked to both the incidence and severity of NVP. Paradoxically, NVP appears to be positively associated with a favourable outcome of pregnancy, including increased birth weight and gestational age. The mechanisms by which NVP favours the outcome of pregnancy are not known. They may be related to women increasing their nutrient intake to alleviate symptoms, improving the quality of their diet or reducing energy expenditure. Alternatively, adaptation to a reduced nutrient intake might stimulate the expression of growth factors and affect placentation or metabolism, thus favouring fetal growth when NVP resolves.

  19. Linking nutrient enrichment, sediment erodibility and biofilms

    NASA Astrophysics Data System (ADS)

    Conrad, B.; Mahon, R.; Sojka, S. L.

    2014-12-01

    Sediment movement in coastal lagoons affects nutrient flux and primary producer growth. Previous research has shown that sediment erodibility is affected by biofilm concentration and that growth of benthic organisms, which produce biofilm, is affected by nutrient enrichment. However, researchers have not examined possible links between nutrient addition and sediment erodibility. We manipulated nutrient levels in the water column of 16 microcosms filled with homogenized sediment from a shallow coastal lagoon and artificial seawater to determine the effects on biofilm growth, measured through chlorophyll a and colloidal carbohydrate concentrations. Erosion tests using a Gust microcosm were conducted to determine the relationship between sediment erodibility and biofilm concentration. Results show that carbohydrate levels decreased with increasing nutrient enrichment and were unrelated to chlorophyll concentrations and erodibility. The nutrient levels did not predictably affect the chlorophyll levels, with lower chlorophyll concentrations in the control and medium enrichment treatments than the low and high enrichment treatments. Controls on biofilm growth are still unclear and the assumed relationship between carbohydrates and erodibility may be invalid. Understanding how biofilms respond to nutrient enrichment and subsequent effects on sediment erodibility is essential for protecting and restoring shallow coastal systems.

  20. Perspectives of healthcare providers and HIV-affected individuals and couples during the development of a Safer Conception Counseling Toolkit in Kenya: stigma, fears, and recommendations for the delivery of services.

    PubMed

    Mmeje, Okeoma; Njoroge, Betty; Akama, Eliud; Leddy, Anna; Breitnauer, Brooke; Darbes, Lynae; Brown, Joelle

    2016-01-01

    Reproduction is important to many HIV-affected individuals and couples and healthcare providers (HCPs) are responsible for providing resources to help them safely conceive while minimizing the risk of sexual and perinatal HIV transmission. In order to fulfill their reproductive goals, HIV-affected individuals and their partners need access to information regarding safer methods of conception. The objective of this qualitative study was to develop a Safer Conception Counseling Toolkit that can be used to train HCPs and counsel HIV-affected individuals and couples in HIV care and treatment clinics in Kenya. We conducted a two-phased qualitative study among HCPs and HIV-affected individuals and couples from eight HIV care and treatment sites in Kisumu, Kenya. We conducted in-depth interviews (IDIs) and focus group discussions (FGDs) to assess the perspectives of HCPs and HIV-affected individuals and couples in order to develop and refine the content of the Toolkit. Subsequently, IDIs were conducted among HCPs who were trained using the Toolkit and FGDs among HIV-affected individuals and couples who were counseled with the Toolkit. HIV-related stigma, fears, and recommendations for delivery of safer conception counseling were assessed during the discussions. One hundred and six individuals participated in FGDs and IDIs; 29 HCPs, 49 HIV-affected women and men, and 14 HIV-serodiscordant couples. Participants indicated that a safer conception counseling and training program for HCPs is needed and that routine provision of safer conception counseling may promote maternal and child health by enhancing reproductive autonomy among HIV-affected couples. They also reported that the Toolkit may help dispel the stigma and fears associated with reproduction in HIV-affected couples, while supporting them in achieving their reproductive goals. Additional research is needed to evaluate the Safer Conception Toolkit in order to support its implementation and use in HIV care and

  1. Changes in Streamflow and the Flux of Nutrients in the Mississippi-Atchafalaya River Basin, USA, 1980-2007

    USGS Publications Warehouse

    Battaglin, William A.; Aulenbach, Brent T.; Vecchia, Aldo; Buxton, Herbert T.

    2010-01-01

    decreased. However, the flux of total phosphorus between the baseline period and subsequent 5-year periods has increased. The average spring (April, May, and June) streamflow and fluxes of silica, total nitrogen, nitrate, and orthophosphate to the Gulf of Mexico also decreased, whereas the spring flux of total phosphorus has increased. Similar changes in streamflow and nutrient flux were observed at many sites Buxtonwithin the basin. The inputs of water, total nitrogen, and total phosphorus from the major subbasins of the Mississippi-Atchafalaya River Basin as a percentage of the to-the-gulf totals have increased from the Ohio River Basin, decreased from the Missouri River Basin, and remained relatively unchanged from the Upper Mississippi, Red, and Arkansas River Basins. Changes in streamflow and nutrient fluxes are related, but short-term variations in sources of streamflow and nutrients complicate the interpretation of factors that affect nutrient delivery to the Gulf of Mexico. Parametric time-series models are used to try and separate natural variability in nutrient flux from changes due to other causes. Results indicate that the decrease in annual nutrient fluxes that has occurred between the 1980-1996 baseline period and more recent years can be largely attributed to natural causes (climate and streamflow) and not management actions or other human controlled activities in the Mississippi-Atchafalaya River Basin. The downward trends in total nitrogen, nitrate, ammonium, and orthophosphate that were detected at either the Mississippi River near St. Francisville, La., or the Atchafalaya River at Melville, La., occurred prior to 1995. In spite of the general decrease in nutrient flux, the average size of the Gulf of Mexico hypoxic zone has increased between 1997 and 2007. The reasons for this are not clear but could be due to the type or nature of nutrient delivery. Whereas the annual flux of total nitrogen to the Gulf of Mexico has decreased, the proporti

  2. Nutrients, neurodevelopment, and mood.

    PubMed

    Casper, Regina C

    2004-12-01

    Human neurodevelopment is the result of genetic and environmental interactions. This paper examines the role of prenatal nutrition relative to psychiatric disorders and explores the relationship among nutrients, mood changes, and mood disorders. Epidemiologic studies have found that adults who were born with a normal, yet low birth weight have an increased susceptibility to diseases such as coronary heart disease, diabetes, and stroke in adulthood. Prenatal caloric malnutrition, low birth weight, and prematurity also increase the risk for neurodevelopmental disorders, schizophrenia, affective disorders, and schizoid and antisocial personality disorders. Placebo-controlled studies in medicated patients suggest that add-on treatment with omega-3 fatty acids, particularly eicosapentaenoic acid, may ameliorate symptoms of major depressive disorder. Additional studies are necessary to confirm any benefits for bipolar disorders.

  3. Administration of a multistrain probiotic product (VSL#3) to women in the perinatal period differentially affects breast milk beneficial microbiota in relation to mode of delivery.

    PubMed

    Mastromarino, Paola; Capobianco, Daniela; Miccheli, Alfredo; Praticò, Giulia; Campagna, Giuseppe; Laforgia, Nicola; Capursi, Teresa; Baldassarre, Maria E

    2015-01-01

    Probiotic supplementation to a mother during the perinatal period can have a positive impact on the breast milk composition. The aim of our study was to evaluate the effect of oral supplementation with the probiotic VSL#3, during late pregnancy and lactation, on breast milk levels of beneficial bacteria and some functional components (oligosaccharides and lactoferrin) potentially able to have a positive influence on the microbiota. Breast milk microbiota was analyzed by conventional and quantitative real-time PCR. In a double-blind, placebo-controlled, randomized trial, 66 women took daily either the probiotic (n=33) or a placebo (n=33). Intergroup analysis demonstrated that the amounts of both lactobacilli and bifidobacteria were significantly higher in the colostrum and mature milk of the mothers taking VSL#3 in comparison to those taking placebo. The analysis of bacterial strains and species present in breast milk of VSL#3 supplemented mothers indicated that the administered probiotic microorganisms did not pass from maternal gut to mammary gland. In women with vaginal delivery, significantly higher amounts of lactobacilli and bifidobacteria were detected in colostrum and mature milk of probiotic treated group in comparison to placebo group, whereas no significant difference was observed between groups in women who had caesarean section, neither in colostrum nor in mature milk. Milk levels of oligosaccharides and lactoferrin were similar in placebo and probiotic supplemented groups at all timepoints and regardless of the mode of delivery. Our results indicate a probiotic-dependent modulation of breast milk microbiota in vaginally delivering women, possibly exerted through a systemic effect.

  4. Thigh oxygen uptake at the onset of intense exercise is not affected by a reduction in oxygen delivery caused by hypoxia.

    PubMed

    Christensen, Peter M; Nordsborg, Nikolai Baastrup; Nybo, Lars; Mortensen, Stefan P; Sander, Mikael; Secher, Niels H; Bangsbo, Jens

    2012-10-15

    In response to hypoxic breathing most studies report slower pulmonary oxygen uptake (Vo2) kinetics at the onset of exercise, but it is not known if this relates to an actual slowing of the Vo2 in the active muscles(.) The aim of the present study was to evaluate whether thigh Vo2 is slowed at the onset of intense exercise during acute exposure to hypoxia. Six healthy male subjects (25.8 ± 1.4 yr, 79.8 ± 4.0 kg, means ± SE) performed intense (100 ± 6 watts) two-legged knee-extensor exercise for 2 min in normoxia (NOR) and hypoxia [fractional inspired oxygen concentration (Fi(O2)) = 0.13; HYP]. Thigh Vo2 was measured by frequent arterial and venous blood sampling and blood flow measurements. In arterial blood, oxygen content was reduced (P < 0.05) from 191 ± 5 ml O2/l in NOR to 180 ± 5 ml O2/l in HYP, and oxygen pressure was reduced (P < 0.001) from 111 ± 4 mmHg in NOR to 63 ± 4 mmHg in HYP. Thigh blood flow was the same in NOR and HYP, and thigh oxygen delivery was consequently reduced (P < 0.05) in HYP, but femoral arterial-venous oxygen difference and thigh Vo(2) were similar in NOR and HYP. In addition, muscle lactate release was the same in NOR and HYP, and muscle lactate accumulation during the first 25 s of exercise determined from muscle biopsy sampling was also similar (0.35 ± 0.07 and 0.36 ± 0.07 mmol·kg dry wt(-1)·s(-1) in NOR and HYP). Thus the increase in thigh Vo2 was not attenuated at the onset of intense knee-extensor exercise despite a reduction in oxygen delivery and pressure.

  5. Nutrient Density Scores.

    ERIC Educational Resources Information Center

    Dickinson, Annette; Thompson, William T.

    1979-01-01

    Announces a nutrient density food scoring system called the Index of Nutritional Quality (INQ). It expresses the ratio between the percent RDA of a nutrient and the percent daily allowance of calories in a food. (Author/SA)

  6. Using a non-invasive technique in nutrition: synchrotron radiation infrared microspectroscopy spectroscopic characterization of oil seeds treated with different processing conditions on molecular spectral factors influencing nutrient delivery.

    PubMed

    Zhang, Xuewei; Yu, Peiqiang

    2014-07-02

    Non-invasive techniques are a key to study nutrition and structure interaction. Fourier transform infrared microspectroscopy coupled with a synchrotron radiation source (SR-IMS) is a rapid, non-invasive, and non-destructive bioanalytical technique. To understand internal structure changes in relation to nutrient availability in oil seed processing is vital to find optimal processing conditions. The objective of this study was to use a synchrotron-based bioanalytical technique SR-IMS as a non-invasive and non-destructive tool to study the effects of heat-processing methods and oil seed canola type on modeled protein structure based on spectral data within intact tissue that were randomly selected and quantify the relationship between the modeled protein structure and protein nutrient supply to ruminants. The results showed that the moisture heat-related processing significantly changed (p<0.05) modeled protein structures compared to the raw canola (control) and those processing by dry heating. The moisture heating increased (p<0.05) spectral intensities of amide I, amide II, α-helices, and β-sheets but decreased (p<0.05) the ratio of modeled α-helices to β-sheet spectral intensity. There was no difference (p>0.05) in the protein spectral profile between the raw and dry-heated canola tissue and between yellow- and brown-type canola tissue. The results indicated that different heat processing methods have different impacts on the protein inherent structure. The protein intrinsic structure in canola seed tissue was more sensitive and more response to the moisture heating in comparison to the dry heating. These changes are expected to be related to the nutritive value. However, the current study is based on limited samples, and more large-scale studies are needed to confirm our findings.

  7. Nutrient dynamics and food-web stability

    SciTech Connect

    DeAngelis, D.L.; Mulholland, P.J.; Palumbo, A.V.; Steinman, A.D.; Huston, M.A.; Elwood, J.W. )

    1989-01-01

    The importance of nutrient limitation and recycling in ecosystems is widely recognized. Nutrients, defined in the broad sense as all material elements vital to biological functions, are in such small supply that they limit production in many ecosystems. Such limitation can affect ecosystem properties, including the structure and dynamics of the food webs that link species through their feeding relationships. What are the effects of limiting nutrients on the stability of ecosystem food webs Most of the literature on food web stability centers around the dynamics of population numbers and/or biomasses. Nevertheless, a growing body of theoretical and empirical research considers the role that both nutrient limitation and recycling can play in stability. In this paper, it is the authors objective to summarize the current understanding of several important types of stability. The theoretical and empirical evidence relating these types of stability and nutrient cycling is described. A central generalization is produced in each case.

  8. Quantifying nutrient export and deposition with a dynamic landscape evolution model for the lake Bolsena watershed, Italy

    NASA Astrophysics Data System (ADS)

    Pelorosso, Raffaele; Temme, Arnoud; Gobattoni, Federica; Leone, Antonio

    2010-05-01

    Excessive nutrient loads from upstream watershed activities such as agriculture, hydrological modifications, and urban runoff, have been identified as the leading cause of deterioration in assessed lakes and reservoirs (USEPA, 2000; Leone et al., 2001; Leone et al., 2003). Excessive nutrient transport into lakes and reservoirs may accelerate eutrophication rates, causing negative impacts on aesthetic and water quality. As reservoirs become eutrophic, they are depleted in oxygen and enriched in suspended solids, with heavy consequences for ecosystems and natural habitats. Management of nutrient loads into reservoirs requires knowledge of nutrient transport and delivery from the watershed-stream system (Ripa, 2003). Managing uncultivated lands in watersheds may be a cost effective way to improve water quality in agricultural landscapes, and recent advances in landscape ecology highlight important relationships between the structural configuration of these lands and nutrient redistribution (e.g., Forman 1987; Barrett and others 1990). Many studies have been carried out to underline and explain how landscape characteristics and structure may affect these processes. In these studies, relations between land cover and nutrient storage were analyzed using geographic information systems (GIS) (e.g. Lucas, 2002). Nutrients are generally transported from the landscape into streams during runoff events; however, they may also enter stream flow from other sources such as groundwater recharge and point source effluent discharges (Lucas, 2002; Nielsen, 2007; Waldron, 2008; Castillo, 2009). Water moves nutrients and delivers them to downstream water bodies such as lakes and reservoirs so that erosion phenomena play an essential role in determining nutrients fluxes and deposition. On the one hand, several hydrological models take into account nutrients reactions, movements and deposition - coupling soil erosion processes with transport equations (Bartley, 2004; Lű, 2010). On the

  9. Lipid-based nutrient supplements do not affect the risk of malaria or respiratory morbidity in 6- to 18-month-old Malawian children in a randomized controlled trial

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is evidence to support the use of lipid-based nutrient supplements (LNSs) to promote child growth and development in low-income countries, but there is also a concern regarding the safety of using iron-fortified products in malaria-endemic areas. The objective of this study was to test the hyp...

  10. Duodenal luminal nutrient sensing

    PubMed Central

    Rønnestad, Ivar; Akiba, Yasutada; Kaji, Izumi; Kaunitz, Jonathan D

    2016-01-01

    The gastrointestinal mucosa is exposed to numerous chemical substances and microorganisms, including macronutrients, micronutrients, bacteria, endogenous ions, and proteins. The regulation of mucosal protection, digestion, absorption and motility is signaled in part by luminal solutes. Therefore, luminal chemosensing is an important mechanism enabling the mucosa to monitor luminal conditions, such as pH, ion concentrations, nutrient quantity, and microflora. The duodenal mucosa shares luminal nutrient receptors with lingual taste receptors in order to detect the five basic tastes, in addition to essential nutrients, and unwanted chemicals. The recent ‘de-orphanization’ of nutrient sensing G protein-coupled receptors provides an essential component of the mechanism by which the mucosa senses luminal nutrients. In this review, we will update the mechanisms of and underlying physiological and pathological roles in luminal nutrient sensing, with a main focus on the duodenal mucosa. PMID:25113991

  11. Forceps Delivery

    MedlinePlus

    ... provider might limit the amount of time you push. Your baby is facing the wrong direction. A forceps delivery might be needed if your baby is facing up (occiput posterior position) rather than down (occiput anterior ...

  12. Delivery presentations

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000621.htm Delivery presentations To use the sharing features on this page, ... baby by cesarean birth (C-section) . Less Common Presentations With the brow-first position, the baby's head ...

  13. Nutrient load summaries for major lakes and estuaries of the Eastern United States, 2002

    USGS Publications Warehouse

    Moorman, Michelle C.; Hoos, Anne B.; Bricker, Suzanne B.; Moore, Richard B.; García, Ana María; Ator, Scott W.

    2014-01-01

    Nutrient enrichment of lakes and estuaries across the Nation is widespread. Nutrient enrichment can stimulate excessive plant and algal growth and cause a number of undesirable effects that impair aquatic life and recreational activities and can also result in economic effects. Understanding the amount of nutrients entering lakes and estuaries, the physical characteristics affecting the nutrient processing within these receiving waterbodies, and the natural and manmade sources of nutrients is fundamental to the development of effective nutrient reduction strategies. To improve this understanding, sources and stream transport of nutrients to 255 major lakes and 64 estuaries in the Eastern United States were estimated using Spatially Referenced Regression on Watershed attributes (SPARROW) nutrient models.

  14. Digital data used to relate nutrient inputs to water quality in the Chesapeake Bay watershed, version 3.0

    USGS Publications Warehouse

    Brakebill, John W.; Preston, Stephen D.

    2004-01-01

    Chesapeake Bay restoration efforts are focused on improving water quality, living resources, and ecological habitats by 2010. One aspect of the water-quality restoration is the refinement of strategies designed to implement nutrient-reduction practices within the Bay watershed. These strategies are being refined and implemented by resource managers of the Chesapeake Bay Program (CBP), a partnership comprised of various Federal, State, and local agencies that includes jurisdictions within Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia, and the District of Columbia. The U.S. Geological Survey (USGS), an active member of the CBP, provides necessary water-quality information for these Chesapeake Bay nutrient-reduction strategy revisions and evaluations. The formulation and revision of effective nutrient-reduction strategies requires detailed scientific information and an analytical understanding of the sources, transport, and delivery of nutrients to the Chesapeake Bay. The USGS is supporting these strategies by providing scientific information to resource managers that can help them evaluate and understand these processes. One statistical model available to resource managers is a collection of SPAtially Referenced Regressions On Watershed (SPARROW) attributes, which uses a nonlinear regression approach to spatially relate nutrient sources and watershed characteristics to nutrient loads of streams throughout the Chesapeake Bay watershed. Developed by the USGS, information generated by SPARROW can help resource managers determine the geographical distribution and relative contribution of nutrient sources and the factors that affect their transport to the Bay. Nutrient source information representing the late 1990s time period was obtained from several agencies and used to create and compile digital spatial datasets of total nitrogen and total phosphorus contributions that served as input sources to the SPARROW models. These data represent

  15. Fish-derived nutrient hotspots shape coral reef benthic communities.

    PubMed

    Shantz, Andrew A; Ladd, Mark C; Schrack, Elizabeth; Burkepile, Deron E

    2015-12-01

    Animal-derived nutrients play an important role in structuring nutrient regimes within and between ecosystems. When animals undergo repetitive, aggregating behavior through time, they can create nutrient hotspots where rates of biogeochemical activity are higher than those found in the surrounding environment. In turn, these hotspots can influence ecosystem processes and community structure. We examined the potential for reef fishes from the family Haemulidae (grunts) to create nutrient hotspots and the potential impact of these hotspots on reef communities. To do so, we tracked the schooling locations of diurnally migrating grunts, which shelter at reef sites during the day but forage off reef each night, and measured the impact of these fish schools on benthic communities. We found that grunt schools showed a high degree of site fidelity, repeatedly returning to the same coral heads. These aggregations created nutrient hotspots around coral heads where nitrogen and phosphorus delivery was roughly 10 and 7 times the respective rates of delivery to structurally similar sites that lacked schools of these fishes. In turn, grazing rates of herbivorous fishes at grunt-derived hotspots were approximately 3 times those of sites where grunts were rare. These differences in nutrient delivery and grazing led to distinct benthic communities with higher cover of crustose coralline algae and less total algal abundance at grunt aggregation sites. Importantly, coral growth was roughly 1.5 times greater at grunt hotspots, likely due to the important nutrient subsidy. Our results suggest that schooling reef fish and their nutrient subsidies play an important role in mediating community structure on coral reefs and that overfishing may have important negative consequences on ecosystem functions. As such, management strategies must consider mesopredatory fishes in addition to current protection often offered to herbivores and top-tier predators. Furthermore, our results suggest that

  16. Developmental Strategy For Effective Sampling To Detect Possible Nutrient Fluxes In Oligotrophic Coastal Reef Waters In The Caribbean

    NASA Astrophysics Data System (ADS)

    Mendoza, W. G.; Corredor, J. E.; Ko, D.; Zika, R. G.; Mooers, C. N.

    2008-05-01

    The increasing effort to develop the coastal ocean observing system (COOS) in various institutions has gained momentum due to its high value to climate, environmental, economic, and health issues. The stress contributed by nutrients to the coral reef ecosystem is among many problems that are targeted to be resolved using this system. Traditional nutrient sampling has been inadequate to resolve issues on episodic nutrient fluxes in reef regions due to temporal and spatial variability. This paper illustrates sampling strategy using the COOS information to identify areas that need critical investigation. The area investigated is within the Puerto Rico subdomain (60-70oW, 15-20oN), and Caribbean Time Series (CaTS), World Ocean Circulation Experiment (WOCE), Intra-America Sea (IAS) ocean nowcast/forecast system (IASNFS), and other COOS-related online datasets are utilized. Nutrient profile results indicate nitrate is undetectable in the upper 50 m apparently due to high biological consumption. Nutrients are delivered in Puerto Rico particularly in the CaTS station either via a meridional jet formed from opposing cyclonic and anticyclonic eddies or wind-driven upwelling. The strong vertical fluctuation in the upper 50 m demonstrates a high anomaly in temperature and salinity and a strong cross correlation signal. High chlorophyll a concentration corresponding to seasonal high nutrient influx coincides with higher precipitation accumulation rates and apparent riverine input from the Amazon and Orinoco Rivers during summer (August) than during winter (February) seasons. Non-detectability of nutrients in the upper 50 m is a reflection of poor sampling frequency or the absence of a highly sensitive nutrient analysis method to capture episodic events. Thus, this paper was able to determine the range of depths and concentrations that need to be critically investigated to determine nutrient fluxes, nutrient sources, and climatological factors that can affect nutrient delivery

  17. Mechanisms of nutrient sensing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The term nutrient sensing has emerged to describe the molecular mechanisms by which nutrients and their metabolites interact with various cell surface receptors, intracellular signaling proteins, and nuclear receptors and modulate the activity of a complex network of signaling pathways that regulate...

  18. Diagnosing oceanic nutrient deficiency

    NASA Astrophysics Data System (ADS)

    Moore, C. Mark

    2016-11-01

    The supply of a range of nutrient elements to surface waters is an important driver of oceanic production and the subsequent linked cycling of the nutrients and carbon. Relative deficiencies of different nutrients with respect to biological requirements, within both surface and internal water masses, can be both a key indicator and driver of the potential for these nutrients to become limiting for the production of new organic material in the upper ocean. The availability of high-quality, full-depth and global-scale datasets on the concentrations of a wide range of both macro- and micro-nutrients produced through the international GEOTRACES programme provides the potential for estimation of multi-element deficiencies at unprecedented scales. Resultant coherent large-scale patterns in diagnosed deficiency can be linked to the interacting physical-chemical-biological processes which drive upper ocean nutrient biogeochemistry. Calculations of ranked deficiencies across multiple elements further highlight important remaining uncertainties in the stoichiometric plasticity of nutrient ratios within oceanic microbial systems and caveats with regards to linkages to upper ocean nutrient limitation. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  19. Nutrient Enrichment Increases Mortality of Mangroves

    PubMed Central

    Lovelock, Catherine E.; Ball, Marilyn C.; Martin, Katherine C.; C. Feller, Ilka

    2009-01-01

    Nutrient enrichment of the coastal zone places intense pressure on marine communities. Previous studies have shown that growth of intertidal mangrove forests is accelerated with enhanced nutrient availability. However, nutrient enrichment favours growth of shoots relative to roots, thus enhancing growth rates but increasing vulnerability to environmental stresses that adversely affect plant water relations. Two such stresses are high salinity and low humidity, both of which require greater investment in roots to meet the demands for water by the shoots. Here we present data from a global network of sites that documents enhanced mortality of mangroves with experimental nutrient enrichment at sites where high sediment salinity was coincident with low rainfall and low humidity. Thus the benefits of increased mangrove growth in response to coastal eutrophication is offset by the costs of decreased resilience due to mortality during drought, with mortality increasing with soil water salinity along climatic gradients. PMID:19440554

  20. National Nutrient Database for Standard Reference - Find Nutrient Value of Common Foods by Nutrient

    MedlinePlus

    ... Nutrient: Second Nutrient: Third Nutrient: Food Subset: Food Groups: Select food groups (10 maximum) Sort by: Measure by: * required field ​ USDA Food Composition Databases Software developed by the National Agricultural ...

  1. Nutrient Control Seminars

    EPA Science Inventory

    These Nutrient Control Seminars will present an extensive state-of-the-technology review of the engineering design and operation of nitrogen and phosphorous control technologies and techniques applied at municipal wastewater treatment plants (WWTPs). These seminars will present ...

  2. Nutrient Control Design Manual

    EPA Science Inventory

    The Nutrient Control Design Manual will present an extensive state-of-the-technology review of the engineering design and operation of nitrogen and phosphorous control technologies and techniques applied at municipal wastewater treatment plants (WWTPs). This manual will present ...

  3. TERRESTRIAL AND MARINE SOURCES OF NUTRIENTS TO STREAMS IN THE OREGON COAST RANGE

    EPA Science Inventory

    Research on nutrient delivery to Pacific Northwest streams generally focuses on watershed processes and land use, but anadromous fish also can serve as a significant source of nutrients and energy to the streams where they return and die. To understand the relative importance of...

  4. Cropping and tillage strategies to minimize off-site impacts of excess nutrients in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    If the conditions under which residue materials leach or sorb nutrients can be identified, it may be possible to adopt cropping and management practices that reduce nutrient delivery by overland flow. Conservation practices such as contouring, strip cropping, conservation tillage, terraces, and buff...

  5. Delivery Innovations.

    PubMed

    2017-03-01

    The need for innovations in care delivery is recognized by providers, payers, and patients alike. Hospitals, physicians, and other clinicians are experimenting with new models of care designed to better meet patients' needs, reduce administrative burdens, and lower costs. The Affordable Care Act placed the Medicare and Medicaid programs at the center of a national effort to experiment with delivery and payment models designed to improve care and contain costs. These public-sector efforts have often aligned with private initiatives, such as the use of reference pricing-in which an insurer will only pay for a service at the price available from the lowest-cost provider. Employers in the public and private sectors have adopted value-based insurance design, in which copayments and deductibles are calibrated to the clinical benefit obtained from different services. Patients have the most to gain-or lose-from delivery innovations. Better, more efficient care should translate into better health and lower costs, but payment models designed to encourage innovation may have the unintended effect of limiting access to care.

  6. Landscape influence on soil carbon and nutrient levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Past runoff, erosion, and management practices influence nutrient levels on the landscape. These starting levels affect future nutrient transport due to runoff, erosion, and leaching events. The purpose of this study was to examine closed-depression landscape effects on surface soil organic matter, ...

  7. Nutrient concentrations and loads in the northeastern United States - Status and trends, 1975-2003

    USGS Publications Warehouse

    Trench, Elaine C. Todd; Moore, Richard B.; Ahearn, Elizabeth A.; Mullaney, John R.; Hickman, R. Edward; Schwarz, Gregory E.

    2012-01-01

    undeveloped category includes some large drainage basins with point-source discharges and small percentages of developed land; in these basins, streamflow from undeveloped headwater areas dilutes streamflow in more urbanized reaches, and dampens but does not eliminate the point-source "signal" of higher nutrient loads. Median total nitrogen yields generally do not exceed 1,700 lb/mi2/yr, and median total phosphorus yields generally do not exceed 100 lb/mi2/yr, in the drainage basins that are least affected by human land-use and waste-disposal practices. Agricultural and urban land use has increased nutrient yields substantially relative to undeveloped drainage basins. Median total nitrogen yields for 24 agricultural basins ranged from 1,700 to 26,000 lb/mi2/yr, and median total phosphorus yields ranged from 94 to 1,000 lb/mi2/yr. The maximum estimated total nitrogen and total phosphorus yields, 32,000 and 16,000 lb/mi2/yr, respectively, for all stations in the region were in small (less than 50 square miles (mi2)) agricultural drainage basins. Median total nitrogen yields ranged from 1,400 to 17,000 lb/mi2/yr in 26 urbanized drainage basins, and median total phosphorus yields ranged from 43 to 1,900 lb/mi2/yr. Urbanized drainage basins with the highest nutrient yields are generally small (less than 300 mi2) and are drained by streams that receive major point-source discharges. Instream nutrient loads were evaluated relative to loads from point-source discharges in four drainage basins: the Quinebaug River Basin in Connecticut, Massachusetts, and Rhode Island; the Raritan River Basin in New Jersey; the Patuxent River Basin in Maryland; and the James River Basin in Virginia. Long-term downward trends in nutrient loads, coupled with similar trends in flow-adjusted nutrient concentrations, indicate long-term reductions in the delivery of most nutrients to these streams. However, the absence of recent downward trends in load for most nutrients, coupled with instream concentrations

  8. Mucoadhesive drug delivery systems

    PubMed Central

    Shaikh, Rahamatullah; Raj Singh, Thakur Raghu; Garland, Martin James; Woolfson, A David; Donnelly, Ryan F.

    2011-01-01

    Mucoadhesion is commonly defined as the adhesion between two materials, at least one of which is a mucosal surface. Over the past few decades, mucosal drug delivery has received a great deal of attention. Mucoadhesive dosage forms may be designed to enable prolonged retention at the site of application, providing a controlled rate of drug release for improved therapeutic outcome. Application of dosage forms to mucosal surfaces may be of benefit to drug molecules not amenable to the oral route, such as those that undergo acid degradation or extensive first-pass metabolism. The mucoadhesive ability of a dosage form is dependent upon a variety of factors, including the nature of the mucosal tissue and the physicochemical properties of the polymeric formulation. This review article aims to provide an overview of the various aspects of mucoadhesion, mucoadhesive materials, factors affecting mucoadhesion, evaluating methods, and finally various mucoadhesive drug delivery systems (buccal, nasal, ocular, gastro, vaginal, and rectal). PMID:21430958

  9. Surface Water Nutrient Budget Controlled by Vegetation Succession in the Deglaciating Copper River Basin, Southcentral Alaska

    NASA Astrophysics Data System (ADS)

    Tomco, P. L.; Zulueta, R. C.; Welker, J. M.

    2011-12-01

    In southcentral Alaska, rapid climate change is manifested by extensive recession of glaciers. This is accompanied by an acceleration of plant succession, as recently deglaciated landscapes evolve to form mature forests and wetlands over time. As ice melt exposes ancient labile nutrients, and as vegetation succession generates high ecosystem productivity, changes in the patterns of dissolved C and N transport from terrestrial to aquatic systems are hypothesized, with cascading impacts on in-river, estuarine and possibly ocean nutrient processing. The Copper River watershed, at 63,000 km2, is the largest drainage basin in the Gulf of Alaska, and derives the major portion of discharge from glacier melt. The commercial fishery based on returning salmon is valued at 25 million dollars, and with salmon return directly linked to phytoplankton blooms in the Gulf of Alaska, understanding nutrient delivery to the marine environment is vital in determining population dynamics of marine and freshwater organisms at all trophic levels. To make predictions about the evolution of terrestrial nutrient contributions to the Copper River, we employ a space-for-time substitution at two endmembers representative of glacial successional stages in the watershed: 1) Lakina River, a recently deglaciated ecosystem dominated by rocky glacial debris containing early successional vegetation species (Dryas, spp., Shepherdia spp., and Salix spp.), and 2) May Creek, a mature spruce-dominated forested ecosystem with surface water contributions from permafrost, snow melt, and precipitation. In addition, we attempted to determine the relative contribution of source water to May Creek via sampling of two nearby springs throughout the season. To determine the seasonality of each site's nutrient budget, we measured dissolved organic carbon (DOC), dissolved organic nitrogen (DON), soluble reactive phosphorus (SRP), δ18O, δD, conductivity, NH4-N, NO3-N, Fe (soluble and colloidal), and Si flux from grab

  10. Global and regional drivers of nutrient supply, primary production and CO2 drawdown in the changing Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Tremblay, Jean-Éric; Anderson, Leif G.; Matrai, Patricia; Coupel, Pierre; Bélanger, Simon; Michel, Christine; Reigstad, Marit

    2015-12-01

    The main environmental factors driving spatial patterns, variability and change in primary production (PP) in the Arctic Ocean are reviewed. While instantaneous PP rates are predominantly influenced by the local factors affecting light penetration through clouds, sea ice and water, net PP (NPP) at the annual scale is conditioned by a hierarchy of remote and local processes that affect nutrient supply and light availability in general. Nutrient supply sets spatial differences in realized or potential trophic status (i.e. oligotrophic or eutrophic), whereas light availability modulates PP within each regime. Horizontal nutrient supply through Atlantic and Pacific ocean gateways differ markedly, which is explained by their position at opposite ends of the global meridional overturning circulation and imbalanced nitrogen (N) cycling in the Pacific sector. Nutrient supply by rivers is locally important, but does not appear to sustain a major portion of overall pan-Arctic NPP so far. Horizontal nutrient inputs to the surface Arctic Ocean are eventually transferred to the halocline through winter convection and the decomposition of settling organic matter. The subsequent re-injection of these nutrients to the euphotic zone varies by two orders of magnitude across sectors, depending on the strength and persistence of the vertical stratification. Such differences in nutrient delivery are commensurate with those of PP and NPP rates. Widespread N deficiency in surface waters fosters the occurrence and seasonal persistence of subsurface layers of maximum chlorophyll a (SCM) and phytoplankton carbon biomass in several sectors. The contribution of these layers to NPP is possibly higher in the Arctic than in thermally-stratified waters of the subtropical gyres due to a combination of extreme acclimation to low light and a shallow nitracline in the former. The overall impacts of SCM layers on biogeochemical fluxes remain to be quantified directly, both regionally and at the pan

  11. On-the-Move Nutrient Delivery System Performance Characteristics

    DTIC Science & Technology

    2008-09-01

    types - ranging from simple sugar ( monosaccharide fructose or disaccharide sucrose) to more complex sugars (short length maltodextrin (Grain...the drink produced. If the concentrate bag is placed on a low location relative to the water reservoir, e.g., low on the water carrier vs . near the

  12. Strategy for nutrient control in modern effluent treatment plants.

    PubMed

    Sivard, A; Ericsson, T; Larsson, B

    2007-01-01

    The fate of nutrients in the modern effluent treatment plant depends on several factors, for example type of treatment plant, availability of nutrients in the specific effluent, dosing of nutrients and sludge age/production. New technologies with the aim to increase the efficiency and stability of the conventional activated sludge process have strongly affected the possibilities to control discharge of nutrients in pulp and paper effluents. A paradox is that a reduction of organic material may often lead to an increase of nutrient discharges. It is of the utmost importance that the operators have good knowledge of the factors affecting nutrient uptake and release in order to minimise nutrient discharge and obtain optimal plant performance. Dosing of nitrogen and phosphorus is one key factor in the sensitive balance in most pulp and paper effluent treatment plants. Correct dosing is crucial as high or low doses might lead not only to increased discharge of nutrients but also to severe operational problems with poor sludge quality, which in turn affects the plant performance for longer periods.

  13. The effect of advection on the nutrient reservoir in the North Atlantic subtropical gyre.

    PubMed

    Palter, Jaime B; Lozier, M Susan; Barber, Richard T

    2005-09-29

    Though critically important in sustaining the ocean's biological pump, the cycling of nutrients in the subtropical gyres is poorly understood. The supply of nutrients to the sunlit surface layer of the ocean has traditionally been attributed solely to vertical processes. However, horizontal advection may also be important in establishing the availability of nutrients. Here we show that the production and advection of North Atlantic Subtropical Mode Water introduces spatial and temporal variability in the subsurface nutrient reservoir beneath the North Atlantic subtropical gyre. As the mode water is formed, its nutrients are depleted by biological utilization. When the depleted water mass is exported to the gyre, it injects a wedge of low-nutrient water into the upper layers of the ocean. Contrary to intuition, cold winters that promote deep convective mixing and vigorous mode water formation may diminish downstream primary productivity by altering the subsurface delivery of nutrients.

  14. Prodrug Strategies in Ocular Drug Delivery

    PubMed Central

    Barot, Megha; Bagui, Mahuya; Gokulgandhi, Mitan R.; Mitra, Ashim K.

    2015-01-01

    Poor bioavailability of topically instilled drug is the major concern in the field of ocular drug delivery. Efflux transporters, static and dynamic ocular barriers often possess rate limiting factors for ocular drug therapy. Different formulation strategies like suspension, ointment, gels, nanoparticles, implants, dendrimers and liposomes have been employed in order to improve drug permeation and retention by evading rate limiting factors at the site of absorption. Chemical modification such as prodrug targeting various nutrient transporters (amino acids, peptide and vitamin) has evolved a great deal ofintereSt to improve ocular drug delivery. In this review, we have discussed various prodrug strategies which have been widely applied for enhancing therapeutic efficacy of ophthalmic drugs. The purpose of this review is to provide an update on the utilization of prodrug concept in ocular drug delivery. In addition, this review will highlight ongoing academic and industrial research and development in terms of ocular prodrug design and delivery. PMID:22530907

  15. Food Affects Human Behavior.

    ERIC Educational Resources Information Center

    Kolata, Gina

    1982-01-01

    A conference on whether food and nutrients affect human behavior was held on November 9, 1982 at the Massachusetts Institute of Technology. Various research studies on this topic are reviewed, including the effects of food on brain biochemistry (particularly sleep) and effects of tryptophane as a pain reducer. (JN)

  16. Nutrient Requirements in Adolescence.

    ERIC Educational Resources Information Center

    McKigney, John I,; Munro, Hamish N.

    It is important to understand the nutrient requirements and the significance of nutrition both in pubescence and adolescence. The pubescent growth spurt is characterized by an increase in body size and a change in proportion of different tissues. Both of these factors are of great nutritional importance, since there is reason to believe that the…

  17. Analytic Models of Oxygen and Nutrient Diffusion, Metabolism Dynamics, and Architecture Optimization in Three-Dimensional Tissue Constructs with Applications and Insights in Cerebral Organoids

    PubMed Central

    2016-01-01

    Diffusion models are important in tissue engineering as they enable an understanding of gas, nutrient, and signaling molecule delivery to cells in cell cultures and tissue constructs. As three-dimensional (3D) tissue constructs become larger, more intricate, and more clinically applicable, it will be essential to understand internal dynamics and signaling molecule concentrations throughout the tissue and whether cells are receiving appropriate nutrient delivery. Diffusion characteristics present a significant limitation in many engineered tissues, particularly for avascular tissues and for cells whose viability, differentiation, or function are affected by concentrations of oxygen and nutrients. This article seeks to provide novel analytic solutions for certain cases of steady-state and nonsteady-state diffusion and metabolism in basic 3D construct designs (planar, cylindrical, and spherical forms), solutions that would otherwise require mathematical approximations achieved through numerical methods. This model is applied to cerebral organoids, where it is shown that limitations in diffusion and organoid size can be partially overcome by localizing metabolically active cells to an outer layer in a sphere, a regionalization process that is known to occur through neuroglial precursor migration both in organoids and in early brain development. The given prototypical solutions include a review of metabolic information for many cell types and can be broadly applied to many forms of tissue constructs. This work enables researchers to model oxygen and nutrient delivery to cells, predict cell viability, study dynamics of mass transport in 3D tissue constructs, design constructs with improved diffusion capabilities, and accurately control molecular concentrations in tissue constructs that may be used in studying models of development and disease or for conditioning cells to enhance survival after insults like ischemia or implantation into the body, thereby providing a

  18. Effect of polycarbophil on the absorption of nutrients.

    PubMed

    Yamada, T; Nagata, O; Tamai, I; Tsuji, A

    1996-05-01

    The effects of polycarbophil on the absorption of various nutrients were evaluated by several in situ methods. Polycarbophil reduced the absorption of 3-O-methyl-D-glucose (3-OMG) and L-phenylalanine in the in situ loop and the in situ perfusion methods, but it did not affect the absorption of these nutrients in an open system, the in situ modified loop method, which is closer to physiological conditions. It also did not affect the absorption of vitamin A or phosphatidylcholine-L-alpha-dipalmitoyl in the latter system. These results indicate that the absorption of nutrients is probably not altered by polycarbophil under physiological conditions.

  19. Chlorophyll a as a Briocriterion in Developing Nutrient Criteria for Estuaries

    EPA Science Inventory

    The purpose of nutrient criteria for aquatic systems is to protect their designated uses. Nutrients do not directly affect designated uses of estuarine and near-coastal waters, but can affect primary producers, which may in turn affect designated uses either directly or indirectl...

  20. Insects, infestations and nutrient fluxes

    NASA Astrophysics Data System (ADS)

    Michalzik, B.

    2012-04-01

    endemic situations (Larrson and Tenow 1980). However, at times of insect mass outbreaks with leaf area losses up to 100%, nutrient fluxes are strongly affected at the ecosystem level and consequently attract greater attention (Grace 1986). In this context, mass outbreaks of herbivore insects constitute a class of ecosystem disturbance (Pickett and White 1985). More specific, insect pests meet the criteria of biogeochemical "hot spots" and "hot moments" (McClain et al. 2003) as they induce temporal-spatial process heterogeneity or changes in biogeochemical reaction rates, but not necessarily changes in the structure of ecosystems or landscapes. This contribution presents a compilation of literature and own research data on insect herbivory effects on nutrient cycling and ecosystem functioning from the plot to the catchment scale. It focuses on temperate forest ecosystems and on short-term impacts as exerted by two focal functional groups of herbivore canopy insects (leaf and sap feeders). In detail, research results on effects operating on short temporal scales are presented including a) alterations in throughfall fluxes encompassing dissolved and particulate organic matter fractions, b) alterations in the amount, timing and quality of frass and honeydew deposition and c) soil microbial activity and decomposition processes.

  1. Harmonization of nutrient intake values.

    PubMed

    King, Janet C; Garza, Cutberto

    2007-03-01

    The conceptual framework for the various NIVs is depicted in figure 1 along with the methodological approaches and applications. The NIVs consist of two values derived from a statistical evaluation of data on nutrient requirements, the average nutrient requirement (ANR), or nutrient toxicities, the upper nutrient level (UNL). The individual nutrient levelx (INLx) is derived from the distribution of average nutrient requirements. The percentile chosen is often 98%, which is equivalent to 2 SD above the mean requirement. Concepts underlying the NIVs include criteria for establishing a nutrient requirement, e.g., ferritin stores, nitrogen balance, or serum vitamin C. Once the requirement for the absorbed nutrient is determined, it may be necessary to adjust the value for food sources, i.e., bioavailability, or host factors, such as the effect of infection on nutrient utilization. Other concepts that committees may want to consider when establishing NIVs include the effects of genetic variation on nutrient requirements and the role of the nutrient in preventing long-term disease. Two fundamental uses of NIVs are for assessing the adequacy of nutrient intakes and for planning diets for individuals and populations. Establishing the NIV using the statistical framework proposed in this report improves the efficacy of the values for identifying risks of nutrient deficiency or excess among individuals and populations. NIVs also are applied to a number of aspects of food and nutrition policy. Some examples include regulatory issues and trade, labeling, planning programs for alleviating public health nutrition problems, food fortification, and dietary guidance.

  2. One-time tillage of no-till: Effects on nutrients, mycorrhizae, and phosphorus uptake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stratification of nutrient availability, especially of P, that develops with continuous no-till (NT) can affect runoff nutrient concentration and possibly nutrient uptake. The effects of composted manure application and one-time tillage of NT on the distribution of soil chemical properties, root co...

  3. Assisted delivery with forceps

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000509.htm Assisted delivery with forceps To use the sharing features on ... called vacuum assisted delivery . When is a Forceps Delivery Needed? Even after your cervix is fully dilated ( ...

  4. Interactive effects of nutrient additions and predation on infaunal communities

    USGS Publications Warehouse

    Posey, M.H.; Alphin, T.D.; Cahoon, L.; Lindquist, D.; Becker, M.E.

    1999-01-01

    Nutrient additions represent an important anthropogenic stress on coastal ecosystems. At moderate levels, increased nutrients may lead to increased primary production and, possibly, to increased biomass of consumers although complex trophic interactions may modify or mask these effects. We examined the influence of nutrient additions and interactive effects of trophic interactions (predation) on benthic infaunal composition and abundances through small-scale field experiments in 2 estuaries that differed in ambient nutrient conditions. A blocked experimental design was used that allowed an assessment of direct nutrient effects in the presence and absence of predation by epibenthic predators as well as an assessment of the independent effects of predation. Benthic microalgal production increased with experimental nutrient additions and was greater when infaunal abundances were lower, but there were no significant interactions between these factors. Increased abundances of one infaunal taxa, Laeonereis culveri, as well as the grazer feeding guild were observed with nutrient additions and a number of taxa exhibited higher abundances with predator exclusion. In contrast to results from freshwater systems there were no significant interactive effects between nutrient additions and predator exclusion as was predicted. The infaunal responses observed here emphasize the importance of both bottom-up (nutrient addition and primary producer driven) and top-down (predation) controls in structuring benthic communities. These processes may work at different spatial and temporal scales, and affect different taxa, making observation of potential interactive effects difficult.

  5. Nutrient profiling: the new environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 2005 Dietary Guidelines for Americans (DGA) recommends that individuals choose nutrient-dense foods to help meet nutrient needs without consuming excess calories, a concept that is supported by health professionals and nutrition organizations. With an increased emphasis on nutrient density, the ...

  6. Simulations of the impact of high pulse atmospheric deposition events on a low nutrient low chlorophyll (LNLC) marine ecosystem

    NASA Astrophysics Data System (ADS)

    Christodoulaki, Sylvia; Petihakis, George; Tsiaras, Konstantinos; Triantafyllou, George; Mihalopoulos, Nikolaos; Kanakidou, Maria

    2014-05-01

    Nutrient availability controls ocean productivity and partitioning of carbon between the ocean and atmosphere, mediated by the limiting potential of macro and micronutrients such as N, P, Fe and Si. Atmospheric deposition is a major pathway for nutrient delivery with potential to alter the role of the ocean from a sink to a source of CO2 and vice versa. Mediterranean region is of interest for both its marine and atmospheric environments. Its Sea is one of the world's most oligotrophic regions in terms of both primary productivity and chlorophyll-a concentration. Its atmosphere is a cross road of air masses of distinct origin highly affected by both natural and anthropogenic emissions. These emissions strongly interact in the atmosphere, due to the high photochemical activity in the area, leading to the formation of nutrients such as nitrogen compounds. Dust aerosols from the African continent are also affecting the area and act as carriers of nutrients such as iron and phosphorus. In the Eastern Basin, where nutrient riverine inputs are very low, wet and dry atmospheric inputs of N and P are the main source of new nutrients in the euphotic zone of the open sea, particularly during the stratification period. In the present study, the impact of an intense atmospheric nitrogen and phosphorus deposition pulse event on the marine ecosystem in the East Mediterranean Sea is investigated. This is achieved by coupling atmospheric and sea water observations with a 1-D ocean physical-biogeochemical model, set up for the Cretan Sea as a representative E. Mediterranean open sea area (Christodoulaki et al., 2012, Journal of Marine Systems, doi: 10.1016/j.jmarsys.2012.07.007). Atmospheric deposition measurements of Dissolved Inorganic Phosphorous and Nitrogen are obtained from the station of Finokalia, shown to be a representative background station for atmospheric observations in the area, whereas, oceanographic data are obtained from the M3A station. Analysis of this high pulse

  7. Trends in nutrients

    USGS Publications Warehouse

    Heathwaite, A.L.; Johnes, P.J.; Peters, N.E.

    1996-01-01

    The roles of nitrogen (N) and phosphorus (P) as key nutrients determining the trophic status of water bodies are examined, and evidence reviewed for trends in concentrations of N and P species which occur in freshwaters, primarily in northern temperate environments. Data are reported for water bodies undergoing eutrophication and acidification, especially water bodies receiving increased nitrogen inputs through the atmospheric deposition of nitrogen oxides (NOx). Nutrient loading on groundwaters and surface freshwaters is assessed with respect to causes and rates of (change, relative rates of change for N and P, and implications of change for the future management of lakes, rivers and groundwaters. In particular, the nature and emphasis of studies for N species and P fractions in lakes versus rivers and groundwaters are contrasted. This review paper primarily focuses on results from North America and Europe, particularly for the UK where a wide range of data sets exists. Few nutrient loading data have been published on water bodies in less developed countries; however, some of the available data are presented to provide a global perspective. In general, N and P concentrations have increased dramatically (>20 times background concentrations) in many areas and causes vary considerably, ranging from urbanization to changes in agricultural practices.

  8. Evaluation of nutrient specifications for broiler breeders.

    PubMed

    Wilson, H R; Harms, R H

    1984-07-01

    Two experiments were conducted to determine if previously suggested nutrient requirements of broiler breeders (23 g protein, 850 mg sulfur amino acids, 4.5 g calcium, and 750 mg phosphorus/bird/day) are in excess and could be reduced during the laying period. In Experiment 1, Cobb color-sex broiler breeders were fed daily nutrient allowances that were 100.0, 96.3, 92.5, 89.4, and 86.6% of the suggested requirements. In Experiment 2, Cobb feather-sex breeders were fed daily allowances that were 92.5, 89.4, 86.6, 83.4, and 80.9% of the suggested requirements. Birds on all diets were fed the same energy level; however, energy varied with season to maintain body weight. Egg production, fertility, hatchability, egg weight, and shell quality were not significantly affected by the reductions in nutrient intake in either experiment. The diet with the lowest nutrient level (80.9% of the suggested requirement) was adequate, indicating a considerable margin of safety for the stated requirements. Body weight was quite variable but tended to decrease with nutrient restriction. Weights of broilers hatched from treated breeders were not significantly affected at 49 days of age by the breeder dietary treatments. These results indicate that broiler breeder diets formulated to meet presently suggested requirements have a large margin of safety and a reduction of specifications by approximately 10% is suggested. The revised daily intakes recommended are: 20.6 g protein, 754 mg sulfur amino acids, 400 mg methionine, 938 mg lysine, 1379 mg arginine, 256 mg tryptophan, 4.07 g calcium, 683 mg total phosphorus, and 170 mg sodium.

  9. Siletz River nutrients: Effects of biosolids application

    EPA Science Inventory

    Stream water nutrients were measured in the Siletz River, Oregon, with the goal of comparing dissolved nutrient concentrations, primarily the nitrogenous nutrients nitrate and ammonium, with previously collected data for the Yaquina and Alsea Rivers for the nutrient criteria prog...

  10. Nutrient dynamics: Chapter 3

    USGS Publications Warehouse

    Likens, Gene E.; LaBaugh, James W.; Buso, Donald C.; Bade, Darren; Winter, Thomas C.; Likens, Gene E.

    2009-01-01

    This chapter focuses on the variability and trends in chemical concentrations and fluxes at Mirror Lake during the period 1981–2000. It examines the water and chemical budgets of Mirror Lake to identify and understand better long-term trends in the chemical characteristics of the lake. It also identifies the causes of changes in nutrient concentrations and examines the contribution of hydrologic pathways to the contamination of Mirror Lake by road salt. The role of groundwater and precipitation on water and chemical budgets of the lake are also examined.

  11. Responsive foams for nanoparticle delivery.

    PubMed

    Tang, Christina; Xiao, Edward; Sinko, Patrick J; Szekely, Zoltan; Prud'homme, Robert K

    2015-09-01

    We have developed responsive foam systems for nanoparticle delivery. The foams are easy to make, stable at room temperature, and can be engineered to break in response to temperature or moisture. Temperature-responsive foams are based on the phase transition of long chain alcohols and could be produced using medical grade nitrous oxide as a propellant. These temperature-sensitive foams could be used for polyacrylic acid (PAA)-based nanoparticle delivery. We also discuss moisture-responsive foams made with soap pump dispensers. Polyethylene glycol (PEG)-based nanoparticles or PMMA latex nanoparticles were loaded into Tween 20 foams and the particle size was not affected by the foam formulation or foam break. Using biocompatible detergents, we anticipate this will be a versatile and simple approach to producing foams for nanoparticle delivery with many potential pharmaceutical and personal care applications.

  12. Ocular delivery of macromolecules

    PubMed Central

    Kim, Yoo-Chun; Chiang, Bryce; Wu, Xianggen; Prausnitz, Mark R.

    2014-01-01

    Biopharmaceuticals are making increasing impact on medicine, including treatment of indications in the eye. Macromolecular drugs are typically given by physician-administered invasive delivery methods, because non--invasive ocular delivery methods, such as eye drops, and systemic delivery, have low bioavailability and/or poor ocular targeting. There is a need to improve delivery of biopharmaceuticals to enable less-invasive delivery routes, less-frequent dosing through controlled-release drug delivery and improved drug targeting within the eye to increase efficacy and reduce side effects. This review discusses the barriers to drug delivery via various ophthalmic routes of administration in the context of macromolecule delivery and discusses efforts to develop controlled-release systems for delivery of biopharmaceuticals to the eye. The growing number of macromolecular therapies in the eye needs improved drug delivery methods that increase drug efficacy, safety and patient compliance. PMID:24998941

  13. The micro and macro of nutrients across biological scales.

    PubMed

    Warne, Robin W

    2014-11-01

    During the past decade, we have gained new insights into the profound effects that essential micronutrients and macronutrients have on biological processes ranging from cellular function, to whole-organism performance, to dynamics in ecological communities, as well as to the structure and function of ecosystems. For example, disparities between intake and organismal requirements for specific nutrients are known to strongly affect animal physiological performance and impose trade-offs in the allocations of resources. However, recent findings have demonstrated that life-history allocation trade-offs and even microevolutionary dynamics may often be a result of molecular-level constraints on nutrient and metabolic processing, in which limiting reactants are routed among competing biochemical pathways. In addition, recent work has shown that complex ecological interactions between organismal physiological states such as exposure to environmental stressors and infectious pathogens can alter organismal requirements for, and, processing of, nutrients, and even alter subsequent nutrient cycling in ecosystems. Furthermore, new research is showing that such interactions, coupled with evolutionary and biogeographical constraints on the biosynthesis and availability of essential nutrients and micronutrients play an important, but still under-studied role in the structuring and functioning of ecosystems. The purpose of this introduction to the symposium "The Micro and Macro of Nutrient Effects in Animal Physiology and Ecology" is to briefly review and highlight recent research that has dramatically advanced our understanding of how nutrients in their varied forms profoundly affect and shape ecological and evolutionary processes.

  14. Toward understanding mechanisms controlling urea delivery in a coastal plain watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improved understanding of nutrient mobilization and delivery to surface waters is critical to protecting water quality in agricultural watersheds. Urea, a form of organic nitrogen, is a common nutrient found in fertilizers, manures, and human waste, and is gaining recognition as an important driver ...

  15. Nutrient uptake and mineralization during leaf decay in streams - a model simulation

    SciTech Connect

    Webster, Jackson; Newbold, J. Denis; Thomas, Steve; Valett, H. Maurice; Mulholland, Patrick J

    2009-01-01

    We developed a stoichiometrically explicit computer model to examine how heterotrophic uptake of nutrients and microbial mineralization occurring during the decay of leaves in streams may be important in modifying nutrient concentrations. The simulations showed that microbial uptake can substantially decrease stream nutrient concentrations during the initial phases of decomposition, while mineralization may produce increases in concentrations during later stages of decomposition. The simulations also showed that initial nutrient content of the leaves can affect the stream nutrient concentration dynamics and determine whether nitrogen or phosphorus is the limiting nutrient. Finally, the simulations suggest a net retention (uptake > mineralization) of nutrients in headwater streams, which is balanced by export of particulate organic nutrients to downstream reaches. Published studies support the conclusion that uptake can substantially change stream nutrient concentrations. On the other hand, there is little published evidence that mineralization also affects nutrient concentrations. Also, there is little information on direct microbial utilization of nutrients contained in the decaying leaves themselves. Our results suggest several directions for research that will improve our understanding of the complex relationship between leaf decay and nutrient dynamics in streams.

  16. Does nutrient enrichment compensate fungicide effects on litter decomposition and decomposer communities in streams?

    PubMed

    Fernández, Diego; Tummala, Mallikarjun; Schreiner, Verena C; Duarte, Sofia; Pascoal, Cláudia; Winkelmann, Carola; Mewes, Daniela; Muñoz, Katherine; Schäfer, Ralf B

    2016-05-01

    Nutrient and pesticide pollution are widespread agricultural stressors. Fungicides may affect freshwater fungi, which play an important role in litter decomposition (LD), whereas moderate nutrient enrichment can stimulate LD. We examined potential interaction effects of nutrients and fungicides on decomposer communities and LD in a 14-day two-factorial (fungicide and nutrient treatments) mesocosm experiment. Fungicide exposure was limited to 4days to simulate episodic contamination. Only the microbial community responded significantly to the experimental factors, though non-significant increases >20% were found for invertebrate decomposer weight gain and LD under high-nutrient conditions. Fungal community structure responded more strongly to fungicides than sporulation. Sporulation responded strongest to nutrients. Bacterial community structure was affected by both factors, although only nutrients influenced bacterial density. Our results suggest effects from fungicides at field-relevant levels on the microbial community. Whether these changes propagate to invertebrate communities and LD remains unclear and should be analysed under longer and recurrent fungicide exposure.

  17. Novel central nervous system drug delivery systems.

    PubMed

    Stockwell, Jocelyn; Abdi, Nabiha; Lu, Xiaofan; Maheshwari, Oshin; Taghibiglou, Changiz

    2014-05-01

    For decades, biomedical and pharmaceutical researchers have worked to devise new and more effective therapeutics to treat diseases affecting the central nervous system. The blood-brain barrier effectively protects the brain, but poses a profound challenge to drug delivery across this barrier. Many traditional drugs cannot cross the blood-brain barrier in appreciable concentrations, with less than 1% of most drugs reaching the central nervous system, leading to a lack of available treatments for many central nervous system diseases, such as stroke, neurodegenerative disorders, and brain tumors. Due to the ineffective nature of most treatments for central nervous system disorders, the development of novel drug delivery systems is an area of great interest and active research. Multiple novel strategies show promise for effective central nervous system drug delivery, giving potential for more effective and safer therapies in the future. This review outlines several novel drug delivery techniques, including intranasal drug delivery, nanoparticles, drug modifications, convection-enhanced infusion, and ultrasound-mediated drug delivery. It also assesses possible clinical applications, limitations, and examples of current clinical and preclinical research for each of these drug delivery approaches. Improved central nervous system drug delivery is extremely important and will allow for improved treatment of central nervous system diseases, causing improved therapies for those who are affected by central nervous system diseases.

  18. Substrate and nutrient limitation regulating microbial growth in soil

    NASA Astrophysics Data System (ADS)

    Bååth, Erland

    2015-04-01

    Microbial activity and growth in soil is regulated by several abiotic factors, including temperature, moisture and pH as the most important ones. At the same time nutrient conditions and substrate availability will also determine microbial growth. Amount of substrate will not only affect overall microbial growth, but also affect the balance of fungal and bacterial growth. The type of substrate will also affect the latter. Furthermore, according to Liebig law of limiting factors, we would expect one nutrient to be the main limiting one for microbial growth in soil. When this nutrient is added, the initial second liming factor will become the main one, adding complexity to the microbial response after adding different substrates. I will initially describe different ways of determining limiting factors for bacterial growth in soil, especially a rapid method estimating bacterial growth, using the leucine incorporation technique, after adding C (as glucose), N (as ammonium nitrate) and P (as phosphate). Scenarios of different limitations will be covered, with the bacterial growth response compared with fungal growth and total activity (respiration). The "degree of limitation", as well as the main limiting nutrient, can be altered by adding substrate of different stoichiometric composition. However, the organism group responding after alleviating the nutrient limitation can differ depending on the type of substrate added. There will also be situations, where fungi and bacteria appear to be limited by different nutrients. Finally, I will describe interactions between abiotic factors and the response of the soil microbiota to alleviation of limiting factors.

  19. NUTRIENT ENRICHMENT AND FISHERIES EXPLOITATION: INTERACTIVE EFFECTS ON ESTUARINE LIVING RESOURCES AND THEIR MANAGEMENT

    EPA Science Inventory

    Fisheries exploitation and increased nutrient loadings affect fish and shellfish abudance and production in estuaries. These stressors do not act independently; instead they jointly influence food webs, and each affects the sensitivity of species and ecosystems to the other. Nu...

  20. Coupled Effects of Hyporheic Flow Structure and Metabolic Pattern on Reach-scale Nutrient Uptake

    NASA Astrophysics Data System (ADS)

    Li, A.; Aubeneau, A. F.; Bolster, D.; Tank, J. L.; Packman, A. I.

    2015-12-01

    Co-injections of conservative tracers and nutrients are commonly used to assess net reach-scale nutrient transformation rates and benthic/hyporheic uptake parameters. However, little information is available on spatial metabolic patterns in the benthic and hyporheic regions. Based on observations from real systems, we used particle tracking simulations to explore the effects of localized metabolism on estimates of reach-scale nutrient uptake rates. Metabolism locally depletes nutrient concentrations relative to conservative tracers, causing their concentration profiles of injected nutrients and conservative tracers to diverge. At slow rates of hyporheic exchange relative to rates of metabolism, overall hyporheic nutrient uptake is limited by delivery from the stream, and effective reach-scale nutrient uptake parameters will be controlled by the hyporheic exchange rate. At high rates of hyporheic exchange relative to rates of metabolism, the injected tracer can propagate beyond regions of high microbial activity, which commonly occur near the streambed surface. In this case, the injected tracer may not adequately capture timescales of nutrient replenishment in the most bioactive regions. Reach-scale nutrients uptake rate increases with increasing heterogeneity in local metabolic patterns, altering the shape of breakthrough curves downstream. More observations of hyporheic rates and metabolic patterns are needed to understand how flow heterogeneity and reaction heterogeneity interact to control nutrient dynamics at reach-scale.

  1. Plants adapted to nutrient limitation allocate less biomass into stems in an arid-hot grassland.

    PubMed

    Yan, Bangguo; Ji, Zhonghua; Fan, Bo; Wang, Xuemei; He, Guangxiong; Shi, Liangtao; Liu, Gangcai

    2016-09-01

    Biomass allocation can exert a great influence on plant resource acquisition and nutrient use. However, the role of biomass allocation strategies in shaping plant community composition under nutrient limitations remains poorly addressed. We hypothesized that species-specific allocation strategies can affect plant adaptation to nutrient limitations, resulting in species turnover and changes in community-level biomass allocations across nutrient gradients. In this study, we measured species abundance and the concentrations of nitrogen and phosphorus in leaves and soil nutrients in an arid-hot grassland. We quantified species-specific allocation parameters for stems vs leaves based on allometric scaling relationships. Species-specific stem vs leaf allocation parameters were weighted with species abundances to calculate the community-weighted means driven by species turnover. We found that the community-weighted means of biomass allocation parameters were significantly related to the soil nutrient gradient as well as to leaf stoichiometry, indicating that species-specific allocation strategies can affect plant adaptation to nutrient limitations in the studied grassland. Species that allocate less to stems than leaves tend to dominate nutrient-limited environments. The results support the hypothesis that species-specific allocations affect plant adaptation to nutrient limitations. The allocation trade-off between stems and leaves has the potential to greatly affect plant distribution across nutrient gradients.

  2. Nutrient Sensing Mechanisms and Pathways

    PubMed Central

    Efeyan, Alejo; Comb, William C.; Sabatini, David M.

    2015-01-01

    PREFACE The ability to sense and respond to fluctuations in environmental nutrient levels is a requisite for life. Nutrient scarcity is a selective pressure that has shaped the evolution of most cellular processes. Different pathways that detect intracellular and extracellular levels of sugars, amino acids and lipids, and surrogate metabolites, are then integrated and coordinated at the organismal level via hormonal signals. During food abundance, nutrient sensing pathways engage anabolism and storage, and scarcity triggers homeostatic mechanisms, like the mobilization of internal stores through mechanisms such as autophagy. Nutrient sensing pathways are commonly deregulated in human metabolic diseases. PMID:25592535

  3. Effects of myocardial infarction on the distribution and transport of nutrients and oxygen in porcine myocardium.

    PubMed

    Davis, Bryce H; Morimoto, Yoshihisa; Sample, Chris; Olbrich, Kevin; Leddy, Holly A; Guilak, Farshid; Taylor, Doris A

    2012-10-01

    One of the primary limitations of cell therapy for myocardial infarction is the low survival of transplanted cells, with a loss of up to 80% of cells within 3 days of delivery. The aims of this study were to investigate the distribution of nutrients and oxygen in infarcted myocardium and to quantify how macromolecular transport properties might affect cell survival. Transmural myocardial infarction was created by controlled cryoablation in pigs. At 30 days post-infarction, oxygen and metabolite levels were measured in the peripheral skeletal muscle, normal myocardium, the infarct border zone, and the infarct interior. The diffusion coefficients of fluorescein or FITC-labeled dextran (0.3-70 kD) were measured in these tissues using fluorescence recovery after photobleaching. The vascular density was measured via endogenous alkaline phosphatase staining. To examine the influence of these infarct conditions on cells therapeutically used in vivo, skeletal myoblast survival and differentiation were studied in vitro under the oxygen and glucose concentrations measured in the infarct tissue. Glucose and oxygen concentrations, along with vascular density were significantly reduced in infarct when compared to the uninjured myocardium and infarct border zone, although the degree of decrease differed. The diffusivity of molecules smaller than 40 kD was significantly higher in infarct center and border zone as compared to uninjured heart. Skeletal myoblast differentiation and survival were decreased stepwise from control to hypoxia, starvation, and ischemia conditions. Although oxygen, glucose, and vascular density were significantly reduced in infarcted myocardium, the rate of macromolecular diffusion was significantly increased, suggesting that diffusive transport may not be inhibited in infarct tissue, and thus the supply of nutrients to transplanted cells may be possible. in vitro studies mimicking infarct conditions suggest that increasing nutrients available to

  4. Nutrient fluxes and stoichiometry in a large impounded river-bay system

    NASA Astrophysics Data System (ADS)

    Klump, J. V.; Waples, J. T.; Able, L. M.; Anderson, P. D.; Weckerly, K.; Szmania, D. C.

    2003-04-01

    Reservoir-induced aging of continental runoff has been shown to an anthropogenically induced global phenomenon with estimates that the mean age of river water reaching the coastal ocean has likely tripled historically. This aging is hypothesized to have a significant biogeochemical impact on land-margin systems by altering flow regimes, net water balances and residence times, reaeration of surface waters, carbon cycling processes, and sediment storage and transport. The Fox-Wolf watershed system contains more than 20 reservoirs, impoundments and lakes on the main stems of the two principal rivers that feed Green Bay and Lake Michigan. Consequently, this hydrologic system can be conceived as functioning as a series of linked biogeochemical reactors which retard flow, retain particles, significantly attenuate the flux of materials into sequential downstream "pools", and both process and repackage nutrients via tightly coupled benthic-pelagic biotic interactions. This successional transformation process results in a poorly understood delivery of nutrients, soils and contaminants from upstream sources to downstream receptors in Green Bay and ultimately -- Lake Michigan. Nutrient reprocessing (defined as the sum of all processes affecting nutrients, i.e. fixation, remineralization, repackaging, sedimentation, etc.) within each pool is hypothesized to be primarily a function of: (1) particle-solute and hydraulic residence times, (2) the quality and quantity of inputs, and (3) the food web structure. Overlaid on these dynamics are very strong seasonal forcing factors, including annual temperature cycles that induce order of magnitude variations in temperature dependent reaction rates, and winter ice cover on the upper pool lakes, reservoirs and Green Bay, that halts run off from the land and reduces within-basin mixing. These short term and seasonal loading dynamics result in considerable temporal stochasticity in the capacity of the biotic component of the ecosystem to

  5. Nutrients and neurodevelopment: lipids.

    PubMed

    González, Horacio F; Visentin, Silvana

    2016-10-01

    Nutrients, lipids in particular, make up the central nervous system structure and play major functional roles: they stimulate development, migration, and nerve cell differentiation. They are part of gray matter, white matter, nerve nuclei, and synaptogenesis. Breast milk contains lipids which are crucial for infant brain development. The lipid profile of breast milk was used as a guideline for the development of breast milk substitutes. However, to date, no substitute has matched it. Complementary feeding should include docosahexaenoic acid, arachidonic acid, other polyunsaturated fatty acids, saturated fatty acids, and complex lipids found in milk fat. The lipid composition of breast milk depends on maternal intake and nutritional status during pregnancy and breast-feeding. It has a great impact on development. Our goal is to review scientific literature regarding the role of lipids on infant brain development and the importance of breast milk lipid composition, maternal diet, and complementary feeding.

  6. Nutrient Cycling Study

    SciTech Connect

    Peter A. Pryfogle

    2005-09-01

    The particular goal of this study is to develop measurement techniques for understanding how consortia of organisms from geothermal facilities utilize sulfur and iron for metabolic activity; and in turn, what role that activity plays in initiating or promoting the development of a biofilm on plant substrates. Sulfur cycling is of interest because sulfur is produced in the resource. Iron is found in some of the steel formulations used in plant components and is also added as chemical treatment for reducing sulfide emissions from the plants. This report describes the set-up and operation of a bioreactor for evaluating the response of colonies of geothermal organisms to changes in nutrient and environmental conditions. Data from initial experiments are presented and plans for future testing is discussed.

  7. Maternal Dietary Nutrient Intake and Its Association with Preterm Birth: A Case-control Study in Beijing, China

    PubMed Central

    Zhang, Yan; Zhou, Hong; Perkins, Anthony; Wang, Yan; Sun, Jing

    2017-01-01

    This study aimed to evaluate dietary nutrient intake among Chinese pregnant women by comparison with Chinese Dietary Reference Intakes (DRIs) and to explore the association between dietary nutrients and preterm birth. A case-control design was conducted in Beijing with 130 preterm delivery mothers in case group and 381 term delivery mothers in control group. Information on mothers’ diet was collected using a food frequency questionnaire, and nutrients and energy intakes were subsequently calculated based on DRIs. Multivariate analysis of variance was used to compare the differences between term and preterm groups in relation to dietary nutrients. Dietary nutrient intakes were imbalanced in both groups compared with Chinese DRIs. Preterm delivery mothers had a lower level of fat and vitamin E intake than term delivery mothers (p < 0.05). Multivariate analysis showed lower vitamin E intake in preterm delivery mothers with a prepregnancy BMI < 18.5 kg/m2 (p < 0.05) and higher carbohydrate intake in preterm delivery mothers with prepregnancy BMI ≥ 24 kg/m2 (p < 0.05). An imbalanced diet in both groups and low level of dietary intakes of fat and vitamin E in preterm group suggest health education measures should be taken to improve the dietary quality of pregnant women, especially for those with an abnormal prepregnancy BMI. PMID:28257050

  8. Stoichiometry, herbivory and competition for nutrients: simple models based on planktonic ecosystems.

    PubMed

    Grover, James P

    2002-02-21

    Models are examined in which two prey species compete for two nutrient resources, and are preyed upon by a predator that recycles both nutrients. Two factors determine the effective relative supply of the nutrients, hence competitive outcomes: the external nutrient supply ratio, and the relative recycling of the two nutrients within the system. This second factor is governed by predator stoichiometry--its relative requirements for nutrients in its own biomass. A model with nutrient resources that are essential for the competing prey is detailed. Criteria are given to identify the limiting nutrient for a food chain of one competitor with the predator. Increased supply of this limiting nutrient increases predator density and concentration of this nutrient at equilibrium, while decreasing the concentration of a non-limiting nutrient. Changes in supply or recycling of a non-limiting nutrient affect only the concentration of that nutrient. Criteria for the invasion of a second prey competitor are presented. When different nutrients limit growth of the resident prey and the invader, increased supply or recycling of the invader's limiting nutrient assists invasion, while increased supply or recycling of the resident's limiting nutrient hinders invasion. If the same nutrient limits both resident and invader, then changes in supply and recycling have complex effects on invasion, depending on species properties. In a parameterized model of a planktonic ecosystem, green algae and cyanobacteria coexist over a wide range of nitrogen:phosphorus supply ratios, without predators. When the herbivore Daphnia is added, coexistence is eliminated or greatly restricted, and green algae dominate over a wide range of supply conditions, because the effective supply of P is greatly reduced as Daphnia rapidly recycles N.

  9. Nutrient presses and pulses differentially impact plants, herbivores, detritivores and their natural enemies.

    PubMed

    Murphy, Shannon M; Wimp, Gina M; Lewis, Danny; Denno, Robert F

    2012-01-01

    of anthropogenic nutrient subsidies affects native ecosystems.

  10. Nutrient Presses and Pulses Differentially Impact Plants, Herbivores, Detritivores and Their Natural Enemies

    PubMed Central

    Murphy, Shannon M.; Wimp, Gina M.; Lewis, Danny

    2012-01-01

    of anthropogenic nutrient subsidies affects native ecosystems. PMID:22952814

  11. Short-term effect of nutrient availability and rainfall distribution on biomass production and leaf nutrient content of savanna tree species.

    PubMed

    Barbosa, Eduardo R M; Tomlinson, Kyle W; Carvalheiro, Luísa G; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H T; van Langevelde, Frank

    2014-01-01

    Changes in land use may lead to increased soil nutrient levels in many ecosystems (e.g. due to intensification of agricultural fertilizer use). Plant species differ widely in their response to differences in soil nutrients, and for savannas it is uncertain how this nutrient enrichment will affect plant community dynamics. We set up a large controlled short-term experiment in a semi-arid savanna to test how water supply (even water supply vs. natural rainfall) and nutrient availability (no fertilisation vs. fertilisation) affects seedlings' above-ground biomass production and leaf-nutrient concentrations (N, P and K) of broad-leafed and fine-leafed tree species. Contrary to expectations, neither changes in water supply nor changes in soil nutrient level affected biomass production of the studied species. By contrast, leaf-nutrient concentration did change significantly. Under regular water supply, soil nutrient addition increased the leaf phosphorus concentration of both fine-leafed and broad-leafed species. However, under uneven water supply, leaf nitrogen and phosphorus concentration declined with soil nutrient supply, this effect being more accentuated in broad-leafed species. Leaf potassium concentration of broad-leafed species was lower when growing under constant water supply, especially when no NPK fertilizer was applied. We found that changes in environmental factors can affect leaf quality, indicating a potential interactive effect between land-use changes and environmental changes on savanna vegetation: under more uneven rainfall patterns within the growing season, leaf quality of tree seedlings for a number of species can change as a response to changes in nutrient levels, even if overall plant biomass does not change. Such changes might affect herbivore pressure on trees and thus savanna plant community dynamics. Although longer term experiments would be essential to test such potential effects of eutrophication via changes in leaf nutrient concentration

  12. Short-Term Effect of Nutrient Availability and Rainfall Distribution on Biomass Production and Leaf Nutrient Content of Savanna Tree Species

    PubMed Central

    Barbosa, Eduardo R. M.; Tomlinson, Kyle W.; Carvalheiro, Luísa G.; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H. T.; van Langevelde, Frank

    2014-01-01

    Changes in land use may lead to increased soil nutrient levels in many ecosystems (e.g. due to intensification of agricultural fertilizer use). Plant species differ widely in their response to differences in soil nutrients, and for savannas it is uncertain how this nutrient enrichment will affect plant community dynamics. We set up a large controlled short-term experiment in a semi-arid savanna to test how water supply (even water supply vs. natural rainfall) and nutrient availability (no fertilisation vs. fertilisation) affects seedlings’ above-ground biomass production and leaf-nutrient concentrations (N, P and K) of broad-leafed and fine-leafed tree species. Contrary to expectations, neither changes in water supply nor changes in soil nutrient level affected biomass production of the studied species. By contrast, leaf-nutrient concentration did change significantly. Under regular water supply, soil nutrient addition increased the leaf phosphorus concentration of both fine-leafed and broad-leafed species. However, under uneven water supply, leaf nitrogen and phosphorus concentration declined with soil nutrient supply, this effect being more accentuated in broad-leafed species. Leaf potassium concentration of broad-leafed species was lower when growing under constant water supply, especially when no NPK fertilizer was applied. We found that changes in environmental factors can affect leaf quality, indicating a potential interactive effect between land-use changes and environmental changes on savanna vegetation: under more uneven rainfall patterns within the growing season, leaf quality of tree seedlings for a number of species can change as a response to changes in nutrient levels, even if overall plant biomass does not change. Such changes might affect herbivore pressure on trees and thus savanna plant community dynamics. Although longer term experiments would be essential to test such potential effects of eutrophication via changes in leaf nutrient

  13. Nutrient Needs of Young Athletes.

    ERIC Educational Resources Information Center

    Willenberg, Barbara; Hemmelgarn, Melinda

    1991-01-01

    Explains the nutritional requirements of children and adolescents, and the physiological roles of the major nutrients. Details the nutrient needs of young athletes, including pre- and postgame meals and fluid replacement. Discusses eating disorders and obesity. Advocates a diet rich in complex carbohydrates. (BC)

  14. Nutrient Removal in Wastewater Treatment

    ERIC Educational Resources Information Center

    Shah, Kanti L.

    1973-01-01

    Discusses the sources and effects of nutrients in wastewater, and the methods of their removal in wastewater treatment. In order to conserve water resources and eliminate the cost of nutrient removal, treated effluent should be used wherever possible for irrigation, since it contains all the ingredients for proper plant growth. (JR)

  15. Integrated plant nutrient system - with special emphasis on mineral nutriton and biofertilizers for Black pepper and cardamom - A review.

    PubMed

    K P, Sangeeth; R, Suseela Bhai

    2016-05-01

    Integrated Plant Nutrition System (IPNS) as a concept and farm management strategy embraces and transcends from single season crop fertilization efforts to planning and management of plant nutrients in crop rotations and farming systems on a long-term basis for enhanced productivity, profitability and sustainability. It is estimated that about two-thirds of the required increase in crop production in developing countries will have to come from yield increases from lands already under cultivation. IPNS enhances soil productivity through a balanced use of soil nutrients, chemical fertilizers, combined with organic sources of plant nutrients, including bio-inoculants and nutrient transfer through agro-forestry systems and has adaptation to farming systems in both irrigated and rainfed agriculture. Horticultural crops, mainly plantation crops, management practices include application of fertilizers and pesticides which become inevitable due to the depletion of soil organic matter and incidence of pests and diseases. The extensive use of chemical fertilizers in these crops deteriorated soil health that in turn affected the productivity. To revitalize soil health and to enhance productivity, it is inexorable to enrich the soil using microorganisms. The lacunae observed here is the lack of exploitation of indigenous microbes having the potential to fix atmospheric nitrogen (N) and to solubilize Phosphorus (P) and Potassium (K). The concept of biofertilizer application appears to be technically simple and financially feasible, but the task of developing biofertilizers with efficient strains in appropriate combinations in a consortia mode is not easier. More than developing consortia, a suitable delivery system to discharge the microbial inoculants warranted much effort. This review focuses on the integrated plant nutrition system incorporating biofertilizer with special emphasis on developing and formulating biofertilizer consortium.

  16. Vacuum-assisted delivery

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000514.htm Vacuum-assisted delivery To use the sharing features on ... the baby through the birth canal. When is Vacuum-assisted Delivery Needed? Even after your cervix is ...

  17. Stoichiometric patterns in foliar nutrient resorption across multiple scales

    USGS Publications Warehouse

    Reed, Sasha C.; Townsend, Alan R.; Davidson, Eric A.; Cleveland, Cory C.

    2012-01-01

    *Nutrient resorption is a fundamental process through which plants withdraw nutrients from leaves before abscission. Nutrient resorption patterns have the potential to reflect gradients in plant nutrient limitation and to affect a suite of terrestrial ecosystem functions. *Here, we used a stoichiometric approach to assess patterns in foliar resorption at a variety of scales, specifically exploring how N : P resorption ratios relate to presumed variation in N and/or P limitation and possible relationships between N : P resorption ratios and soil nutrient availability. *N : P resorption ratios varied significantly at the global scale, increasing with latitude and decreasing with mean annual temperature and precipitation. In general, tropical sites (absolute latitudes < 23°26′) had N : P resorption ratios of < 1, and plants growing on highly weathered tropical soils maintained the lowest N : P resorption ratios. Resorption ratios also varied with forest age along an Amazonian forest regeneration chronosequence and among species in a diverse Costa Rican rain forest. *These results suggest that variations in N : P resorption stoichiometry offer insight into nutrient cycling and limitation at a variety of spatial scales, complementing other metrics of plant nutrient biogeochemistry. The extent to which the stoichiometric flexibility of resorption will help regulate terrestrial responses to global change merits further investigation.

  18. Fertilization and pesticides affect mandarin orange nutrient composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of the application of foliar fertilization and pesticide on nutritional quality of mandarin orange juices were evaluated using 1H NMR metabolomics. Significant differences between the use of fertilizer and pesticides during fruit formation were observed, and included changes in sugar, am...

  19. Cation uptake and allocation by red pine seedlings under cation-nutrient stress in a column growth experiment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background and aims: Plant nutrient uptake is affected by environmental stress, but how plants respond to cation nutrient stress is poorly understood. We assessed the impact of varying degrees of cation-nutrient stress on cation uptake in an experimental plant-mineral system. Methods: Column experim...

  20. Articulating feedstock delivery device

    SciTech Connect

    Jordan, Kevin

    2013-11-05

    A fully articulable feedstock delivery device that is designed to operate at pressure and temperature extremes. The device incorporates an articulating ball assembly which allows for more accurate delivery of the feedstock to a target location. The device is suitable for a variety of applications including, but not limited to, delivery of feedstock to a high-pressure reaction chamber or process zone.

  1. Herbivores and nutrients control grassland plant diversity via light limitation.

    PubMed

    Borer, Elizabeth T; Seabloom, Eric W; Gruner, Daniel S; Harpole, W Stanley; Hillebrand, Helmut; Lind, Eric M; Adler, Peter B; Alberti, Juan; Anderson, T Michael; Bakker, Jonathan D; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S; Brudvig, Lars A; Buckley, Yvonne M; Cadotte, Marc; Chu, Chengjin; Cleland, Elsa E; Crawley, Michael J; Daleo, Pedro; Damschen, Ellen I; Davies, Kendi F; DeCrappeo, Nicole M; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A; Knops, Johannes M H; La Pierre, Kimberly J; Leakey, Andrew D B; Li, Wei; MacDougall, Andrew S; McCulley, Rebecca L; Melbourne, Brett A; Mitchell, Charles E; Moore, Joslin L; Mortensen, Brent; O'Halloran, Lydia R; Orrock, John L; Pascual, Jesús; Prober, Suzanne M; Pyke, David A; Risch, Anita C; Schuetz, Martin; Smith, Melinda D; Stevens, Carly J; Sullivan, Lauren L; Williams, Ryan J; Wragg, Peter D; Wright, Justin P; Yang, Louie H

    2014-04-24

    Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

  2. Nutrient cycling and plant dynamics in estuaries: A brief review

    NASA Astrophysics Data System (ADS)

    Flindt, Mogens R.; Pardal, Miguel Ângelo; Lillebø, Ana Isabel; Martins, Irene; Marques, João Carlos

    1999-07-01

    Eutrophication of European estuaries due to massive nutrient loading from urban areas and diffuse runoff from extensively cultivated land areas is analysed. Consequences for the ecology of estuaries, namely changes in plant species composition, which also affects heterotrophic organisms, are approached based on examples showing that the result is often a fundamental structural change of the ecosystem, from a grazing and/or nutrient controlled stable systems to unstable detritus/mineralisation systems, where the turnover of oxygen and nutrients is much more dynamic and oscillations between aerobic and anaerobic states frequently occur. Several relevant aspects are examined, namely the influence of rooted macrophytes on nutrient dynamics, by comparing bare bottom sediments with eelgrass covered sediments, primary production and the development of organic detritus, and hydrodynamics and its relations to the spatial distribution of macrophytes in estuarine systems.

  3. Herbivores and nutrients control grassland plant diversity via light limitation

    USGS Publications Warehouse

    Borer, Elizabeth T.; Seabloom, Eric W.; Gruner, Daniel S.; Harpole, W. Stanley; Hillebrand, Helmut; Lind, Eric M.; Alder, Peter B.; Alberti, Juan; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S.; Brudvig, Lars A.; Buckley, Yvonne M.; Cadotte, Marc; Chu, Cheng-Jin; Cleland, Elsa E.; Crawley, Michael J.; Daleo, Pedro; Damschen, Ellen Ingman; Davies, Kendi F.; DeCrappeo, Nicole M.; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W.; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A.; Knops, Johannes M.H.; La Pierre, Kimberly J.; Leakey, Andrew D.B.; Li, Wei; MacDougall, Andrew S.; McCulley, Rebecca L.; Melbourne, Brett A.; Mitchell, Charles E.; Moore, Joslin L.; Mortensen, Brent; O'Halloran, Lydia R.; Orrock, John L.; Pascual, Jesús; Prober, Suzanne M.; Pyke, David A.; Risch, Anita C.; Schuetz, Martin; Smith, Melinda D.; Stevens, Carly J.; Sullivan, Lauren L.; Williams, Ryan J.; Wragg, Peter D.; Wright, Justin P.; Yang, Louie H.

    2014-01-01

    Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

  4. Gastropod grazers and nutrients, but not light, interact in determining periphytic algal diversity.

    PubMed

    Liess, Antonia; Kahlert, Maria

    2007-05-01

    The potential interactions of grazing, nutrients and light in influencing autotroph species diversity have not previously been considered. Earlier studies have shown that grazing and nutrients interact in determining autotroph species diversity, since grazing decreases species diversity when nutrients (i.e. N or P) limit autotroph growth, but increases it when nutrients are replete. We hypothesized that increased light intensities would intensify the interactions between grazing and nutrients on algal species diversity, resulting in even stronger reductions in algal species diversity through grazing under nutrient-poor conditions, and to even stronger increases of algal species diversity through grazing under nutrient-rich conditions. We studied the effects of grazing (absent, present), nutrients (ambient, N + P enriched) and light (low light, high light) on benthic algal diversity and periphyton C:nutrient ratios (which can indicate algal nutrient limitation) in a factorial laboratory experiment, using the gastropod grazer Viviparus viviparus. Grazing decreased algal biomass and algal diversity, but increased C:P and N:P ratios of periphyton. Grazing also affected periphyton species composition, by decreasing the proportion of Spirogyra sp. and increasing the proportion of species in the Chaetophorales. Grazing effects on diversity as well as on periphyton N:P ratios were weakened when nutrients were added (interaction between grazing and nutrients). Chlorophyll a (Chl a) per area increased with nutrient addition and decreased with high light intensities. Light did not increase the strength of the interaction between grazing and nutrients on periphytic algal diversity. This study shows that nutrient addition substantially reduced the negative effects of grazing on periphytic algal diversity, whereas light did not interact with grazing or nutrient enrichment in determining periphytic algal diversity.

  5. Nutrients related to GLP1 secretory responses.

    PubMed

    Mansour, Asieh; Hosseini, Saeed; Larijani, Bagher; Pajouhi, Mohamad; Mohajeri-Tehrani, Mohammad Reza

    2013-06-01

    The hormone glucagon-like peptide (GLP-1) is secreted from gut endocrine L cells in response to ingested nutrients. The activities of GLP-1 include stimulating insulin gene expression and biosynthesis, improving β-cell proliferation, exogenesis, and survival. Additionally, it prevents β-cell apoptosis induced by a variety of cytotoxic agents. In extrapancreatic tissues, GLP-1 suppresses hunger, delays gastric emptying, acts as an ileal brake, and increases glucose uptake. The pleiotropic actions of GLP-1, especially its glucose-lowering effect, gave rise to the suggestion that it is a novel approach to insulin resistance treatment. Hormones secreted from the gut including GLP-1, which are involved in the regulation of insulin sensitivity and secretions, have been found to be affected by nutrient intake. In recent years, there has been a growing interest in the effect nutrients may have on GLP-1 secretion; some frequently studied dietary constituents include monounsaturated fatty acids, fructooligosaccharides, and glutamine. This review focuses on the influence that the carbohydrate, fat, and protein components of a meal may have on the GLP-1 postprandial responses.

  6. Nutrient addition dramatically accelerates microbial community succession.

    PubMed

    Knelman, Joseph E; Schmidt, Steven K; Lynch, Ryan C; Darcy, John L; Castle, Sarah C; Cleveland, Cory C; Nemergut, Diana R

    2014-01-01

    The ecological mechanisms driving community succession are widely debated, particularly for microorganisms. While successional soil microbial communities are known to undergo predictable changes in structure concomitant with shifts in a variety of edaphic properties, the causal mechanisms underlying these patterns are poorly understood. Thus, to specifically isolate how nutrients--important drivers of plant succession--affect soil microbial succession, we established a full factorial nitrogen (N) and phosphorus (P) fertilization plot experiment in recently deglaciated (∼3 years since exposure), unvegetated soils of the Puca Glacier forefield in Southeastern Peru. We evaluated soil properties and examined bacterial community composition in plots before and one year after fertilization. Fertilized soils were then compared to samples from three reference successional transects representing advancing stages of soil development ranging from 5 years to 85 years since exposure. We found that a single application of +NP fertilizer caused the soil bacterial community structure of the three-year old soils to most resemble the 85-year old soils after one year. Despite differences in a variety of soil edaphic properties between fertilizer plots and late successional soils, bacterial community composition of +NP plots converged with late successional communities. Thus, our work suggests a mechanism for microbial succession whereby changes in resource availability drive shifts in community composition, supporting a role for nutrient colimitation in primary succession. These results suggest that nutrients alone, independent of other edaphic factors that change with succession, act as an important control over soil microbial community development, greatly accelerating the rate of succession.

  7. Assessment of Nutrient Stability in Space Foods

    NASA Technical Reports Server (NTRS)

    Zwart, S. R.; Perchonok, M.; Braby, L. A.; Kloeris, V. A.; Smith, S. M.

    2009-01-01

    Maintaining an intact nutrient supply in the food system flown on spacecraft is a critical issue for mission success and crew health and safety. Early polar expeditions and exploration expeditions by sailing vessels have taught us that a deficiency, or excess, of even a single vitamin in the food supply can be catastrophic. Evidence from ground-based research indicates that some vitamins are destroyed and fatty acids are oxidized (and therefore rendered dangerous or useless) by different types of radiation and by conditions of long-term storage. We hypothesize that radiation and long-term storage in the space-flight environment will affect the stability of vitamins, amino acids, and fatty acids in the space food system. The research objectives of our ongoing stability studies are to determine the stability of water- and fat-soluble vitamins, fatty acids, and amino acids in the space food supply before and after space flight on the International Space Station (ISS). Foods were analyzed after 2 weeks (a flight control), 11, 19, and 28 months of flight. Along with the space-flown foods, ground-based controls matched for time, light, and temperature are analyzed. The flight studies complement planned ground-based studies of the effects of radiation on vitamins, amino acids, and fatty acids. Flight studies are needed because a model based on ground-based data cannot predict all of the effects of the space-flight environment. Flight studies provide a more accurate test system to determine the effects on these nutrients of the temperature, and radiation conditions in the space-flight environment. Ground studies are required to evaluate longer missions and higher radiation levels expected outside low-Earth orbit. In addition to providing information about nutrient stability in space, the results of these studies will help NASA determine if a need exists to develop special packaging that can ensure stability of foods and nutrients in space, or if further studies of nutrient

  8. Nutrient sources and transport along urban flowpaths to aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Finlay, J. C.; Janke, B.; Baker, L. A.; Hobbie, S. E.; Nidzgorski, D.; Sterner, R.; Wilson, B. N.

    2012-12-01

    Water quality of urban freshwater ecosystems is widely impaired by eutrophication, with little recent improvement and much potential for further degradation due to urban expansion and intensification. Despite the degradation of water quality in urban streams and lakes and adjacent coastal areas, relatively little is known about the relative importance of specific nutrient sources and the processes that regulate their movement across highly modified land-water interfaces. To better understand the nutrient sources and cycling that affect aquatic ecosystems, we assess nutrient movement through urban drainage networks in St. Paul, Minnesota. Nutrient concentrations and flux in stormwater at six intensively monitored sites show consistent seasonal patterns, with peaks in total nitrogen (N) and phosphorus (P) in the late spring. Trees contributed to nutrient movement via litterfall and throughfall to impervious surfaces, with peaks in inputs that corresponded to stormwater nutrient patterns. Despite runoff generated primarily from impervious surfaces, organic carbon and nitrogen concentrations were high, with organic N accounting for >80% of stormwater N loading. Together, these data suggested an important role for urban tree canopies in nutrient mobilization in stormwater. Base flow, present in larger storm drains and buried streams, results primarily from groundwater seepage and from outflow of surface water connected to drains. Base flow contributed significantly to nutrient export, particularly for N (33 to 68% of warm season export) but also for P (8 to 34%). Sites with upstream hydrologic connections to lakes and remnant above-ground stream reaches had higher baseflow organic carbon and P, and reduced N concentrations compared to sites dominated by groundwater. Together, these data show that the characteristics of urban vegetation and the nature of human alterations to hydrologic connections are dominant features influencing the form and amount of nutrient movement

  9. Allocation of nutrients to somatic tissues in young ovariectomized grasshoppers.

    PubMed

    Judd, Evan T; Hatle, John D; Drewry, Michelle D; Wessels, Frank J; Hahn, Daniel A

    2010-11-01

    The disposable soma hypothesis predicts that when reproduction is reduced, life span is increased because more nutrients are invested in the soma, increasing somatic repair. Rigorously testing the hypothesis requires tracking nutrients from ingestion to allocation to the soma or to reproduction. Fruit flies on life-extending dietary restriction increase allocation to the soma "relative" to reproduction, suggesting that allocation of nutrients can be associated with extension of life span. Here, we use stable isotopes to track ingested nutrients in ovariectomized grasshoppers during the first oviposition cycle. Previous work has shown that ovariectomy extends life span, but investment of protein in reproduction is not reduced until after the first clutch of eggs is laid. Because ovariectomy does not affect investment in reproduction at this age, the disposable soma hypothesis would predict that ovariectomy should also not affect investment in somatic tissues. We developed grasshopper diets with distinct signatures of ¹³C and ¹⁵N, but that produced equivalent reproductive outputs. These diets are, therefore, appropriate for the reciprocal switches in diet needed for tracking ingested nutrients. Incorporation of stable isotopes into eggs showed that grasshoppers are income breeders, especially for carbon. Allocation to the fat body of nitrogen ingested as adults was slightly increased by ovariectomy; this was our only result that was not consistent with the disposable soma hypothesis. In contrast, ovariectomy did not affect allocation of nitrogen to femoral muscles. Further, allocation of carbon to the fat body or femoral muscles did not appear to be affected by ovariectomy. Total anti-oxidant activities in the hemolymph and femoral muscles were not affected by ovariectomy. These experiments showed that allocation of nutrients was altered little by ovariectomy in young grasshoppers. Additional studies on older individuals are needed to further test the disposable

  10. Energy and Nutrient Intake Monitoring

    NASA Technical Reports Server (NTRS)

    Luckey, T. D.; Venugopal, B.; Hutcheson, D. P.

    1975-01-01

    A passive system to determine the in-flight intake of nutrients is developed. Nonabsorbed markers placed in all foods in proportion to the nutrients selected for study are analyzed by neutron activation analysis. Fecal analysis for each market indicates how much of the nutrients were eaten and apparent digestibility. Results of feasibility tests in rats, mice, and monkeys indicate the diurnal variation of several markers, the transit time for markers in the alimentary tract, the recovery of several markers, and satisfactory use of selected markers to provide indirect measurement of apparent digestibility. Recommendations are provided for human feasibility studies.

  11. Nutrient biofortification of food crops.

    PubMed

    Hirschi, Kendal D

    2009-01-01

    Plant-based foods offer an array of nutrients that are essential for human nutrition and promote good health. However, the major staple crops of the world are often deficient in some of these nutrients. Traditional agricultural approaches can marginally enhance the nutritional value of some foods, but the advances in molecular biology are rapidly being exploited to engineer crops with enhanced key nutrients. Nutritional targets include elevated mineral content, improved fatty acid composition, increased amino acid levels, and heightened antioxidant levels. Unfortunately, in many cases the benefits of these "biofortified" crops to human nutrition have not been demonstrated.

  12. Elevated nutrients change bacterial community composition and connectivity: high throughput sequencing of young marine biofilms.

    PubMed

    Lawes, Jasmin C; Neilan, Brett A; Brown, Mark V; Clark, Graeme F; Johnston, Emma L

    2016-01-01

    Biofilms are integral to many marine processes but their formation and function may be affected by anthropogenic inputs that alter environmental conditions, including fertilisers that increase nutrients. Density composition and connectivity of biofilms developed in situ (under ambient and elevated nutrients) were compared using 454-pyrosequencing of the 16S gene. Elevated nutrients shifted community composition from bacteria involved in higher processes (eg Pseudoalteromonas spp. invertebrate recruitment) towards more nutrient-tolerant bacterial species (eg Terendinibacter sp.). This may enable the persistence of biofilm communities by increasing resistance to nutrient inputs. A core biofilm microbiome was identified (predominantly Alteromonadales and Oceanospirillales) and revealed shifts in abundances of core microbes that could indicate enrichment by fertilisers. Fertiliser decreased density and connectivity within biofilms indicating that associations were disrupted perhaps via changes to energetic allocations within the core microbiome. Density composition and connectivity changes suggest nutrients can affect the stability and function of these important marine communities.

  13. Colloidal drug delivery systems in vaccine delivery.

    PubMed

    Beg, Sarwar; Samad, Abdus; Nazish, Iram; Sultana, Ruksar; Rahman, Mahfoozur; Ahmad, Md Zaki; Akbar, Md

    2013-01-01

    Vaccines play a vital role in the field of community medicine to combat against several diseases of human existence. Vaccines primarily trigger the acquired immune system to develop long-lasting immunity against pathogens. Conventional approaches for vaccine delivery lacks potential to target a particular antigen to develop acquired immunity by specific antibodies. Recent advancements in vaccine delivery showed that inclusion of adjuvants in vaccine formulations or delivery of them in a carrier helps in achieving desired targeting ability, reducing the immunogenicity and significant augmentation in the immune response. Colloidal carriers (liposomes, niosomes, microspheres, proteosomes, virosomes and virus like particles (VLPs), antigen cochleates, dendrimers and carbon nanotubes) have been widely explored for vaccine delivery. Further, surface engineering of these carriers with ligands, functional moieties and monoclonal antibodies tend to enhance the immune recognition potential of vaccines by differentiation of antigen specific memory T-cells. The current review, therefore, provides an updated account on the recent advancements in various colloidal delivery systems in vaccine delivery, outlining the mechanism of immune response initiated by them along with potential applications and marketed instances in an explicit manner.

  14. Nutrient enrichment and fish nutrient tolerance: Assessing biologically relevant nutrient criteria

    USGS Publications Warehouse

    Meador, Michael R.

    2013-01-01

    Relationships between nutrient concentrations and fish nutrient tolerance were assessed relative to established nutrient criteria. Fish community, nitrate plus nitrite (nitrate), and total phosphorus (TP) data were collected during summer low-flow periods in 2003 and 2004 at stream sites along a nutrient-enrichment gradient in an agricultural basin in Indiana and Ohio and an urban basin in the Atlanta, Georgia, area. Tolerance indicator values for nitrate and TP were assigned for each species and averaged separately for fish communities at each site (TIVo). Models were used to predict fish species expected to occur at a site under minimally disturbed conditions and average tolerance indicator values were determined for nitrate and TP separately for expected communities (TIVe). In both areas, tolerance scores (TIVo/TIVe) for nitrate increased significantly with increased nitrate concentrations whereas no significant relationships were detected between TP tolerance scores and TP concentrations. A 0% increase in the tolerance score (TIVo/TIVe = 1) for nitrate corresponded to a nitrate concentration of 0.19 mg/l (compared with a USEPA summer nitrate criterion of 0.17 mg/l) in the urban area and 0.31 mg/l (compared with a USEPA summer nitrate criterion of 0.86 mg/l) in the agricultural area. Fish nutrient tolerance values offer the ability to evaluate nutrient enrichment based on a quantitative approach that can provide insights into biologically relevant nutrient criteria.

  15. The Impact of Extreme Flooding on Mussel and Microbial Nutrient Dynamics at the Water-Sediment Interface

    NASA Astrophysics Data System (ADS)

    Bril, J.; Just, C. L.; Newton, T.; Young, N.; Parkin, G.

    2009-12-01

    Labeled by the National Academy of Engineering as one of fourteen grand challenges for engineering, the management of the nitrogen cycle has become an increasingly difficult obstacle for sustainable development. In an effort to improve nitrogen cycle management practices, we are attempting to expand on the limited scientific knowledge of how aquatic environments are affected by increasing human- and climate-induced changes. To accomplish this, we are using freshwater mussels as a sentinel species to indicate how natural processes within large river systems may be altered by human activity. Freshwater mussels have been referred to as ‘ecosystem engineers’ because they exert control over food resources and alter habitats for other organisms. Also, mussels and bacteria play a major role in nutrient cycling in large river systems by cycling nutrients taken up by phytoplankton and zooplankton. Under ‘normal’ environmental conditions, mussels appear to process nitrogen more rapidly than denitrifying bacteria. However, substantial deposition of carbon-rich sediment resulting from extreme flooding may increase bacterial nitrogen cycling rates and subsequently alter overall denitrification rates. We hypothesize that intense depositions of particulate matter from recent extreme floods in the Upper Mississippi River Basin (UMRB) have altered the freshwater mussel and microbial food webs through physical and chemical means. This work will be done in a 1200-m reach of the UMRB near Buffalo, Iowa. The reach contains a healthy and diverse assemblage of freshwater mussels. A historic flood event during May-July 2008 coincided with intense spring cultivation and nutrient application activities in the heavily farmed landscape of the Upper Midwest and resulted in a significant pulse of agricultural contaminants to the UMRB. This led scientists to predict an almost unprecedented delivery of sediment and nutrients to the mussel bed, the broader Mississippi River, and ultimately

  16. [Effects of biochar on soil nutrients leaching and potential mechanisms: A review].

    PubMed

    Liu, Yu-xue; Lyu, Hao-hao; Shi, Yan; Wang, Yao-feng; Zhong, Zhe-ke; Yang, Sheng-mao

    2015-01-01

    Controlling soil nutrient leaching in farmland ecosystems has been a hotspot in the research field of agricultural environment. Biochar has its unique physical and chemical properties, playing a significant role in enhancing soil carbon storage, improving soil quality and increasing crop yield. As a kind of new exogenous material, biochar has the potential in impacting soil nutrient cycling directly or indirectly, and has profound influences on soil nutrient leaching. This paper analyzed the intrinsic factors affecting how biochar affects soil nutrient leaching, such as the physical and chemical properties of biochar, and the interaction between biochar and soil organisms. Then the latest literatures regarding the external factors, including biochar application rates, soil types, depth of soil layer, fertilization conditions and temporal dynamics, through which biochar influences soil nutrient (especially nitrogen and phosphorus) leaching were reviewed. On that basis, four related action mechanisms were clarified, including direct adsorption of nutrients by biochar due to its micropore structure or surface charge, influencing nutrient leaching through increasing soil water- holding capacity, influencing nutrient cycling through the interaction with soil microbes, and preferential transport of absorbed nutrients by fine biochar particles. At last future research directions for better understanding the interactions between biochar and nutrient leaching in the soil were proposed.

  17. Low body weight gain, low white blood cell count and high serum ferritin as markers of poor nutrition and increased risk for preterm delivery.

    PubMed

    Hsu, Wen-Yin; Wu, Cheng-Hsuan; Hsieh, Charles Tsung-Che; Lo, Hui-Chen; Lin, Jen-Shiou; Kao, Mei-Ding

    2013-01-01

    This study determined factors of preterm delivery in Taiwan. Healthy women (n=520, age 29.1±4.2 y) at 8-12 weeks of pregnancy were recruited from prenatal clinics. Background information, anthropometrics, biochemical parameters, and dietary intake, collected by 24 h-recall were obtained from the first, second, and third trimesters to delivery. Clinical outcomes of neonates were also collected. The results show that 53.7% of women were primiparous and that the incidence of preterm delivery was 6.2%. Body weight gains in the first trimester and throughout pregnancy were significantly lower in mothers with preterm delivery (preterm group) than in mothers with term delivery (term group, p<0.05). Maternal cholesterol intake, circulating white blood cell counts (WBC) and serum albumin were significantly lower and that serum magnesium and ferritin were significantly higher in the preterm group than in the term group. Maternal weight gain was positively correlated with caloric and nutrient intake (p<0.05). Neonatal birth weight was positively correlated with maternal weight gain and intakes of protein and phosphate during pregnancy; with intakes of calories, vitamin B-1 and B-2 in the first trimester; and with intakes of calcium, magnesium, iron and zinc, as well as circulating WBC in the third trimester. However, neonatal birth weight was negatively correlated with serum iron in the third trimester and with serum iron and ferritin at the time of delivery. In conclusion, maternal weight gain in early pregnancy and WBC, mineral intake and iron status in late pregnancy seem to be major factors affecting delivery and neonatal outcomes.

  18. Nutrient vectors and riparian nutrient processing in African semiarid savanna ecosystems

    USGS Publications Warehouse

    Jacobs, Shayne M.; Bechtold, J.S.; Biggs, Harry C.; Grimm, N. B.; McClain, M.E.; Naiman, R.J.; Perakis, Steven S.; Pinay, G.; Scholes, M.C.

    2007-01-01

    This review article describes vectors for nitrogen and phosphorus delivery to riparian zones in semiarid African savannas, the processing of nutrients in the riparian zone and the effect of disturbance on these processes. Semiarid savannas exhibit sharp seasonality, complex hillslope hydrology and high spatial heterogeneity, all of which ultimately impact nutrient fluxes between riparian, upland and aquatic environments. Our review shows that strong environmental drivers such as fire and herbivory enhance nitrogen, phosphorus and sediment transport to lower slope positions by shaping vegetative patterns. These vectors differ significantly from other arid and semiarid ecosystems, and from mesic ecosystems where the impact of fire and herbivory are less pronounced and less predictable. Also unique is the presence of sodic soils in certain hillslopes, which substantially alters hydrological flowpaths and may act as a trap where nitrogen is immobilized while sediment and phosphorus transport is enhanced. Nutrients and sediments are also deposited in the riparian zone during seasonal, intermittent floods while, during the dry season, subsurface movement of water from the stream into riparian soils and vegetation further enrich riparian zones with nutrients. As is found in mesic ecosystems, nutrients are immobilized in semiarid riparian corridors through microbial and plant uptake, whereas dissimilatory processes such as denitrification may be important where labile nitrogen and carbon are in adequate supply and physical conditions are suitablea??such as in seeps, wallows created by animals, ephemeral wetlands and stream edges. Interaction between temporal hydrologic connectivity and spatial heterogeneity are disrupted by disturbances such as large floods and extended droughts, which may convert certain riparian patches from sinks to sources for nitrogen and phosphorus. In the face of increasing anthropogenic pressure, the scientific challenges are to provide a basic

  19. Hydrologic controls on nutrient cycling in an unconfined coastal aquifer.

    PubMed

    Gonneea, Meagan Eagle; Charette, Matthew A

    2014-12-16

    Groundwater is an important pathway for terrestrially derived nutrients to enter the coastal ocean. In coastal aquifers, groundwater transits the subterranean estuary, a region of sharp gradients in redox conditions and the availability of reactants. In one such system (Waquoit Bay, MA, USA), we observed more than a doubling of the groundwater-associated nitrogen flux to surface water during the summer compared to winter due primarily to a reduction in nitrogen attenuation within the subterranean estuary. Because marine groundwater intrusion has been shown to increase during the summer, we calculate a greater contribution of recycled nutrients from the coastal ocean to the subterranean estuary. We posit that the longer residence times within the subterranean estuary during the winter, which would result from reduced marine groundwater circulation, allow oxygen depletion of the groundwater, creating a favorable environment for important nutrient transformations such as nitrification, denitrification, and anammox. The timing of nutrient delivery to the coastal ocean has important implications for coastal marine ecology including the potential development of harmful algal blooms.

  20. Fish extinctions alter nutrient recycling in tropical freshwaters.

    PubMed

    McIntyre, Peter B; Jones, Laura E; Flecker, Alexander S; Vanni, Michael J

    2007-03-13

    There is increasing evidence that species extinctions jeopardize the functioning of ecosystems. Overfishing and other human influences are reducing the diversity and abundance of fish worldwide, but the ecosystem-level consequences of these changes have not been assessed quantitatively. Recycling of nutrients is one important ecosystem process that is directly influenced by fish. Fish species vary widely in the rates at which they excrete nitrogen and phosphorus; thus, altering fish communities could affect nutrient recycling. Here, we use extensive field data on nutrient recycling rates and population sizes of fish species in a Neotropical river and Lake Tanganyika, Africa, to evaluate the effects of simulated extinctions on nutrient recycling. In both of these species-rich ecosystems, recycling was dominated by relatively few species, but contributions of individual species differed between nitrogen and phosphorus. Alternative extinction scenarios produced widely divergent patterns. Loss of the species targeted by fishermen led to faster declines in nutrient recycling than extinctions in order of rarity, body size, or trophic position. However, when surviving species were allowed to increase after extinctions, these compensatory responses had strong moderating effects even after losing many species. Our results underscore the complexity of predicting the consequences of extinctions from species-rich animal communities. Nevertheless, the importance of exploited species in nutrient recycling suggests that overfishing could have particularly detrimental effects on ecosystem functioning.

  1. Nutrient balances as indicators for sustainability of broiler production systems.

    PubMed

    Kratz, S; Halle, I; Rogasik, J; Schnug, E

    2004-04-01

    1. Flock balances of nitrogen, phosphorus, zinc and copper (N, P, Zn, Cu) were calculated in order to evaluate environmental effects of three different broiler production systems (intensive indoor, free range and organic). 2. Nutrient gain in birds per unit nutrient intake (retention) in intensive indoor production was higher than in free range and organic production. 3. Nutrient surplus relative to nutrient retention was higher in organic production than in free range and intensive indoor production. 4. The main reasons for differences in nutrient efficiency between intensive indoor, free range and organic production were duration of growth period, strain of broilers and feeding strategy. 5. The calculation of whole farm indicators (livestock density, N and P excretions per hectare of farmland) demonstrates how defining system boundaries affects the outcome of an evaluation: organic farms had the smallest livestock densities and the lowest N and P excretions per hectare of farmland. 6. In the efforts to reach a more holistic evaluation of agricultural production systems, the definition of adequate system boundaries must be discussed. In addition to nutrient balances, further indicators of sustainability, such as human and ecological toxicity, should be considered.

  2. Dynamics of microorganism populations in recirculating nutrient solutions

    NASA Technical Reports Server (NTRS)

    Strayer, R. F.

    1994-01-01

    This overview covers the basic microbial ecology of recirculating hydroponic solutions. Examples from NASA and Soviet Controlled Ecological Life Support Systems (CELSS) tests and the commercial hydroponic industry will be used. The sources of microorganisms in nutrient solutions include air, water, seeds, plant containers and plumbing, biological vectors, and personnel. Microbial fates include growth, death, and emigration. Important microbial habitats within nutrient delivery systems are root surfaces, hardware surfaces (biofilms), and solution suspension. Numbers of bacteria on root surfaces usually exceed those from the other habitats by several orders of magnitude. Gram negative bacteria dominate the microflora with fungal counts usually much lower. Trends typically show a decrease in counts with increasing time unless stressed plants increase root exudates. Important microbial activities include carbon mineralization and nitrogen transformations. Important detrimental interactions include competition with plants, and human and plant pathogenesis.

  3. A nutrient injection scheme for in situ bio-remediation.

    PubMed

    Lin, C H; Kuo, M C Tom; Su, C Y; Liang, K F; Han, Y L

    2012-01-01

    Geological layers often have different hydraulic conductivities. This paper presents an innovative design for delivering aqueous substrates and nutrients to various stratified layers at desired rates during in-situ bio-stimulation. The new delivery system consists of intermittent porous tubes connected in series with impermeable polyethylene tubes that run horizontally in each stratified layer of a contaminated aquifer. Results of the tracer test indicated that the distribution of tritium through each porous tube was fairly uniform. A mathematical model was also developed to calculate the distribution of water flow through each porous tube. By controlling the permeability and the length of porous tubes placed in stratified layers, the new design provides a means to selectively deliver nutrients to various layers at desired rates according to aquifer heterogeneity.

  4. Dynamics of microorganism populations in recirculating nutrient solutions

    NASA Technical Reports Server (NTRS)

    Strayer, R. F.

    1994-01-01

    This overview covers the basic microbial ecology of recirculating hydroponic solutions. Examples from NASA and Soviet CELSS tests and the commercial hydroponic industry will be used. The sources of microorganisms in nutrient solutions include air, water, seeds, plant containers and plumbing, biological vectors, and personnel. Microbial fates include growth, death, and emigration. Important microbial habitats within nutrient delivery systems are root surfaces, hardware surfaces (biofilms), and solution suspension. Numbers of bacteria on root surfaces usually exceed those from the other habitats by several orders of magnitude. Gram negative bacteria dominate the microflora with fungal counts usually much lower. Trends typically show a decrease in counts with increasing time unless stressed plants increase root exudates. Important microbial activities include carbon mineralization and nitrogen transformations. Important detrimental interactions include competition with plants, and human and plant pathogenesis.

  5. Dynamics of microorganism populations in recirculating nutrient solutions

    NASA Astrophysics Data System (ADS)

    Strayer, R. F.

    1994-11-01

    This overview covers the basic microbial ecology of recirculating hydroponic solutions. Examples from NASA and Soviet CELSS tests and the commercial hydroponic industry will be used. The sources of microorganisms in nutrient solutions include air, water, seeds, plant containers and plumbing, biological vectors, and personnel. Microbial fates include growth, death, and emigration. Important microbial habitats within nutrient delivery systems are root surfaces, hardware surfaces (biofilms), and solution suspension. Numbers of bacteria on root surfaces usually exceed those from the other habitats by several orders of magnitude. Gram negative bacteria dominate the microflora with fungal counts usually much lower. Trends typically show a decrease in counts with increasing time unless stressed plants increase root exudates. Important microbial activities include carbon mineralization and nitrogen transformations. Important detrimental interactions include competition with plants, and human and plant pathogenesis.

  6. Stream Restoration to Manage Nutrients in Degraded Watersheds

    EPA Science Inventory

    Historic land-use change can reduce water quality by impairing the ability of stream ecosystems to efficiently process nutrients such as nitrogen. Study results of two streams (Minebank Run and Big Spring Run) affected by urbanization, quarrying, agriculture, and impoundments in...

  7. Avoidance of dairy products: Implications for nutrient adequacy and health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dairy products are an important contributor of many essential nutrients often lacking in the typical North American diet, including calcium, potassium, and vitamin D, and limiting dairy intake may adversely affect health. Dairy exclusion diets may exacerbate the risk of osteoporosis and negatively i...

  8. Nutrient content at the sediment-water interface of tile-fed agricultural drainage ditches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extensive network of tile drains present in the Midwest USA accelerate losses of nutrients to receiving ditches, rivers and eventually to the Gulf of Mexico. Nutrient inputs from agricultural watersheds and their role in affecting water quality have received increased attention recently; however, be...

  9. Nutrient losses from Fall and Winter-applied manure: Effects of timing and soil temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil temperature is a major environmental factor that affects both the infiltration of meltwater and precipitation, and nutrient cycling. The objectives of this study were to determine nutrient losses in runoff and leachate from fall and winter-applied dairy manure based on the soil temperature at t...

  10. Mesoporous silica nanoparticles as a biomolecule delivery vehicle in plants

    NASA Astrophysics Data System (ADS)

    Hussain, Hashmath I.; Yi, Zhifeng; Rookes, James E.; Kong, Lingxue X.; Cahill, David M.

    2013-06-01

    We report the uptake by wheat, lupin and Arabidopsis of mesoporous silica nanoparticles functionalised with amine cross-linked fluorescein isothiocyanate (MSN-APTES-FITC). The preparation of these particles at room temperature enabled the synthesis of 20 nm particles that contained a network of interconnected pores around 2 nm in diameter. The uptake and distribution of these nanoparticles were examined during seed germination, in roots of plants grown in a hydroponic system and in whole leaves and roots of plants via vacuum infiltration. The nanoparticles did not affect seed germination in lupin and there was no phytotoxicity. Following germination of wheat and lupin grown in a nutrient solution containing nanoparticles, they were found within cells and cell walls of the emerging root and in the vascular transport elements, the xylem, and in other associated cells. In leaves and roots of Arabidopsis the nanoparticles were found, following vacuum infiltration of whole seedlings, to be taken up by the entire leaf and they were principally found in the intercellular spaces of the mesophyll but also throughout much of the root system. We propose that MSNs could be used as a novel delivery system for small molecules in plants.

  11. Light, nutrients and the growth of herbaceous forest species

    NASA Astrophysics Data System (ADS)

    Elemans, Marjet

    2004-12-01

    The herb layer of forests planted on former agricultural land often differs from that of old-growth forest. This study investigates if the expected increased nutrient availability in the shaded conditions of newly planted forests and the plasticity of the species to adjust their biomass allocation to different levels of light and nutrients help to explain these differences in the herb layers of the two forest types. In a greenhouse experiment biomass distribution and production of two species characteristic for the highly shaded forest floor, Circaea lutetiana and Mercurialis perennis, and two species more common in the forest-edge, Aegopodium podagraria and Impatiens parviflora were studied at different levels of light (2%, 8% and 66% of the full light level) and nutrients (30 and 300 kg N ha -1 per year). The main factor affecting allocation and biomass production was light availability. Nutrient supply only had a significant effect at the higher light levels. Species were mainly plastic to changes in light and the two species from the forest floor showed to be more rigid in allocation pattern than the species from the forest-edge. So, although the species from the forest-edge were more plastic, they did not profit from the increased nutrient supply because the main factor affecting biomass distribution and production was light availability.

  12. Causes of preterm delivery.

    PubMed

    Gravett, M G

    1984-10-01

    Although major advances have been made in both obstetric care of the high-risk patient and in neonatal care, prematurity and its consequences remain the major contributor to perinatal mortality. The identification of maternal or obstetric risk factors associated with preterm delivery has enhanced our ability to provide special obstetric care to gravidas at increased risk. The selective management of patients at increased risk for preterm delivery may ultimately reduce the incidence of preterm births. Maternal genital infections are also associated with preterm delivery. Further research is needed to explore the pathogenesis of preterm delivery associated with genital infections, since infections may represent a potentially preventable cause of prematurity.

  13. Nutrient influences on leaf photosynthesis

    SciTech Connect

    Longstreth, D.J.; Nobel, P.S.

    1980-01-01

    The net rate of CO/sub 2/ uptake for leaves of Gossypium hirsutum L. was reduced when the plants were grown at low concentrations of NO/sub 3//sup -/, PO/sub 4//sup 2 -/, or K/sup +/. The water vapor conductance was relatively constant for all nutrient levels, indicating little effect on stomatal response. Although leaves under nutrient stress tended to be lower in chlorophyll and thinner, the ratio of mesophyll surface area to leaf area did not change appreciably. Thus, the reduction in CO/sub 2/ uptake rate at low nutrient levels was due to a decrease in the CO/sub 2/ conductance expressed per unit mesophyll cell wall area (g/sub CO/sup cell//sub 2/). The use of g/sub CO//sup cell//sub 2/ and nutrient levels expressed per unit of mesophyll cell wall provides a new means of assessing nutrient effects on CO/sub 2/ uptake of leaves. 14 figures, 1 table.

  14. TOR Signaling and Nutrient Sensing.

    PubMed

    Dobrenel, Thomas; Caldana, Camila; Hanson, Johannes; Robaglia, Christophe; Vincentz, Michel; Veit, Bruce; Meyer, Christian

    2016-04-29

    All living organisms rely on nutrients to sustain cell metabolism and energy production, which in turn need to be adjusted based on available resources. The evolutionarily conserved target of rapamycin (TOR) protein kinase is a central regulatory hub that connects environmental information about the quantity and quality of nutrients to developmental and metabolic processes in order to maintain cellular homeostasis. TOR is activated by both nitrogen and carbon metabolites and promotes energy-consuming processes such as cell division, mRNA translation, and anabolism in times of abundance while repressing nutrient remobilization through autophagy. In animals and yeasts, TOR acts antagonistically to the starvation-induced AMP-activated kinase (AMPK)/sucrose nonfermenting 1 (Snf1) kinase, called Snf1-related kinase 1 (SnRK1) in plants. This review summarizes the immense knowledge on the relationship between TOR signaling and nutrients in nonphotosynthetic organisms and presents recent findings in plants that illuminate the crucial role of this pathway in conveying nutrient-derived signals and regulating many aspects of metabolism and growth.

  15. N limited herbivore consumer growth and low nutrient regeneration N:P ratios in nutrient poor Swedish lakes along a gradient in DOC concentration

    NASA Astrophysics Data System (ADS)

    Bergström, A. K.; Karlsson, D.; Karlsson, J.; Vrede, T.

    2014-12-01

    Nutrient limitation of primary producers and their consumers can have a large influence on ecosystem productivity. The nature and strength of nutrient limitation is driven both by external factors (nutrient loading) and internal processes (consumer-driven nutrient regeneration). Here we present results from a field study in 16 unproductive headwater lakes in northern subarctic and boreal Sweden where N deposition is low. We assessed the C:N:P stoichiometry of lake water, seston and zooplankton and estimated the consumer driven nutrient regeneration N:P ratio. The elemental imbalances between seston and zooplankton indicated that zooplankton were mainly N limited and regenerated nutrients with low N:P ratios (median 9.7, atomic ratio). The N:P regeneration ratios declined with increasing DOC concentrations, suggesting that catchment release of DOC accentuates the N limitation by providing more P to the lakes. The N:P regeneration ratios were related to responses in phytoplankton bioassays in mid-summer with low N:P regeneration with N limited phytoplankton, and high N:P regeneration with P limited phytoplankton. During other seasons, increased nutrient loading from the surrounding catchments during periods of greater water throughput had stronger effects on phytoplankton nutrient limitation. Our results suggest that herbivore zooplankton are N limited and recycle nutrients with low N:P ratio in low productive lakes with low N deposition. This will, at least during seasons when in-lake processes play an important role in nutrient turn over, contribute to continued N limitation of phytoplankton in these systems. We anticipate that increased N deposition and changes in climate and hydrology may affect this feedback and result in qualitative changes in these ecosystems, changing both autotroph producers and herbivore consumers from N- to P-limitation, eventually affecting important ecosystem characteristics such as productivity and turnover of energy and nutrients.

  16. CADDIS Volume 2. Sources, Stressors and Responses: Nutrients

    EPA Pesticide Factsheets

    Introduction to the nutrients module, when to list nutrients as a candidate cause, ways to measure nutrients, simple and detailed conceptual diagrams for nutrients, nutrients module references and literature reviews.

  17. Formality in Rhetorical Delivery.

    ERIC Educational Resources Information Center

    Skopec, Eric Wm.

    Formality in rhetorical delivery can be defined as a complex variable that represents the speaker's efforts to invoke sociocultural rules of audience control through the nonverbal components of the delivery. This document describes some of the aspects of formality, outlines its significance in rhetorical contexts, and evaluates the concept in…

  18. [The moon and delivery].

    PubMed

    Romero Martínez, Jorge; Guerrero Guijo, Inmaculada; Artura Serrano, Antonio

    2004-11-01

    In different cultures and mythologies, the moon is related with fertility, pregnancy and delivery. Professional obstetricians also notice an increase in care demands on the days when the moon is full. Many studies have been made which try to correlate delivery processes to the phases of the moon with contradictory results. The authors plan to try to find any basis in fact which support these popular beliefs and to discover if lunar phases bear an influence on the distribution of deliveries. They carried out a descriptive transversal study on a total of 1715 unassisted deliveries over the course of ten complete lunar cycles. The authors have carried out a descriptive and inferential analysis, a one way ANOVA and a Kruskal Wallis test on their three data bases which are general, primipara and multipara in which they contemplated the total number of deliveries per phase, the mean of each phase, as well as the central day in each phase of the lunar cycle. The differences found in the distribution of deliveries over the four lunar phases, along with the comparison of the means and the comparison of the number of deliveries on the central day in each phase are not statistically significant. The different phases in the lunar cycle and especially the full moon do not appear to have any influence over the distribution of deliveries in this study.

  19. Programming placental nutrient transport capacity

    PubMed Central

    Fowden, A L; Ward, J W; Wooding, F P B; Forhead, A J; Constancia, M

    2006-01-01

    Many animal studies and human epidemiological findings have shown that impaired growth in utero is associated with physiological abnormalities in later life and have linked this to tissue programming during suboptimal intrauterine conditions at critical periods of development. However, few of these studies have considered the contribution of the placenta to the ensuing adult phenotype. In mammals, the major determinant of intrauterine growth is the placental nutrient supply, which, in turn, depends on the size, morphology, blood supply and transporter abundance of the placenta and on synthesis and metabolism of nutrients and hormones by the uteroplacental tissues. This review examines the regulation of placental nutrient transfer capacity and the potential programming effects of nutrition and glucocorticoid over-exposure on placental phenotype with particular emphasis on the role of the Igf2 gene in these processes. PMID:16439433

  20. Drug Delivery Approaches for the Treatment of Cervical Cancer

    PubMed Central

    Ordikhani, Farideh; Erdem Arslan, Mustafa; Marcelo, Raymundo; Sahin, Ilyas; Grigsby, Perry; Schwarz, Julie K.; Azab, Abdel Kareem

    2016-01-01

    Cervical cancer is a highly prevalent cancer that affects women around the world. With the availability of new technologies, researchers have increased their efforts to develop new drug delivery systems in cervical cancer chemotherapy. In this review, we summarized some of the recent research in systematic and localized drug delivery systems and compared the advantages and disadvantages of these methods. PMID:27447664

  1. Consumers regulate nutrient limitation regimes and primary production in seagrass ecosystems.

    PubMed

    Allgeier, Jacob E; Yeager, Lauren A; Layman, Craig A

    2013-02-01

    Consumer-mediated nutrient supply is increasingly recognized as an important functional process in many ecosystems. Yet, experimentation at relevant spatial and temporal scales is needed to fully integrate this bottom-up pathway into ecosystem models. Artificial reefs provide a unique approach to explore the importance of consumer nutrient supply for ecosystem function in coastal marine environments. We used bioenergetics models to estimate community-level nutrient supply by fishes, and relevant measures of primary production, to test the hypothesis that consumers, via excretion of nutrients, can enhance primary production and alter nutrient limitation regimes for two dominant primary producer groups (seagrass and benthic microalgae) around artificial reefs. Both producer groups demonstrated marked increases in production, as well as shifts in nutrient limitation regimes, with increased fish-derived nutrient supply. Individuals from the two dominant functional feeding groups (herbivores and mesopredators) supplied nutrients at divergent rates and ratios from one another, underscoring the importance of community structure for nutrient supply to primary producers. Our findings demonstrate that consumers, through an underappreciated bottom-up mechanism in marine environments, can alter nutrient limitation regimes and primary production, thereby fundamentally affecting the way these ecosystems function.

  2. Biogeographic patterns of nutrient resorption from Quercus variabilis Blume leaves across China.

    PubMed

    Sun, X; Kang, H; Chen, H Y H; Björn, B; Samuel, B F; Liu, C

    2016-05-01

    The variation in nutrient resorption has been studied at different taxonomic levels and geographic ranges. However, the variable traits of nutrient resorption at the individual species level across its distribution are poorly understood. We examined the variability and environmental controls of leaf nutrient resorption of Quercus variabilis, a widely distributed species of important ecological and economic value in China. The mean resorption efficiency was highest for phosphorus (P), followed by potassium (K), nitrogen (N), sulphur (S), magnesium (Mg) and carbon (C). Resorption efficiencies and proficiencies were strongly affected by climate and respective nutrients concentrations in soils and green leaves, but had little association with leaf mass per area. Climate factors, especially growing season length, were dominant drivers of nutrient resorption efficiencies, except for C, which was strongly related to green leaf C status. In contrast, green leaf nutritional status was the primary controlling factor of leaf nutrient proficiencies, except for C. Resorption efficiencies of N, P, K and S increased significantly with latitude, and were negatively related to growing season length and mean annual temperature. In turn, N, P, K and S in senesced leaves decreased with latitude, likely due to their efficient resorption response to variation in climate, but increased for Mg and did not change for C. Our results indicate that the nutrient resorption efficiency and proficiency of Q. variabilis differed strongly among nutrients, as well as growing environments. Our findings provide important insights into understanding the nutrient conservation strategy at the individual species level and its possible influence on nutrient cycling.

  3. Boosted Regression Tree Models to Explain Watershed Nutrient Concentrations and Biological Condition

    EPA Science Inventory

    Boosted regression tree (BRT) models were developed to quantify the nonlinear relationships between landscape variables and nutrient concentrations in a mesoscale mixed land cover watershed during base-flow conditions. Factors that affect instream biological components, based on ...

  4. DEVELOPMENT OF NUTRIENT EXPOSURE AND BIOLOGICAL RESPONSE INDICATORS FOR LAKE MICHIGAN COASTAL WETLANDS

    EPA Science Inventory

    This study examines how landscape-scale gradient affect sedimentation rates, nutrient exposure, and biological responses in Lake Michigan coastal wetlands, and assess indicators for these trends. Twenty riverine coastal wetlands in Lake Michigan (Herdendorf 1981) were selected t...

  5. Quantitative Models for Ecosystem Assessment in Narragansett Bay: Response to Nutrient Loading and Other Stressors

    EPA Science Inventory

    Multiple drivers, including nutrient loading and climate change, affect the Narragansett Bay ecosystem. Managers are interested in understanding the timing and magnitude of these effects, as well as ecosystem responses to restoration actions, such as the capacity and potential fo...

  6. Nutrient transport by ruminal bacteria: a review.

    PubMed

    Martin, S A

    1994-11-01

    Fermentation pathways have been elucidated for predominant ruminal bacteria, but information is limited concerning the specific transport mechanisms used by these microorganisms for C, energy, and N sources. In addition, it is possible that changes in ruminal environmental conditions could affect transport activity. Five carrier-mediated soluble nutrient transport mechanisms have been identified in bacteria: 1) facilitated diffusion, 2) shock sensitive systems, 3) proton symport, 4) Na+ symport, and the 5) phosphoenolpyruvate phosphotransferase system (PEP-PTS). Several regulatory mechanisms are also involved at the cell membrane to coordinate utilization of different sugars. Recent research has shown that predominant ruminal bacteria are capable of transporting soluble nutrients by several of the mechanisms outlined above. Megasphaera elsdenii, Selenomonas ruminantium, and Streptococcus bovis transport glucose by the PEP-PTS, and S. ruminantium and S. bovis also possess PEP-PTS activity for disaccharides. Glucose PTS activity in S. bovis was highest at a growth pH of 5.0, low glucose concentrations, and a dilution rate of .10 h-1. The cellulolytic ruminal bacterium Fibrobacter succinogenes uses a Na+ symport mechanism for glucose transport that is sensitive to low extracellular pH and ionophores. Sodium also stimulated cellobiose transport by F. succinogenes, and there is evidence for a proton symport in the transport of both arabinose and xylose by S. ruminantium. A chemical gradient of Na+ seems to play an important role in AA transport in several ruminal bacteria. Studying nutrient transport mechanisms in ruminal bacteria will lead to a better understanding of the ruminal fermentation.

  7. Elective Delivery Before 39 Weeks

    MedlinePlus

    ... Delivery, and Postpartum Care Elective Delivery Before 39 Weeks • What is a “medically indicated” delivery? • What is ... the baby grow and develop during the last weeks of pregnancy? • What are the risks for babies ...

  8. Algal remediation of CO₂ and nutrient discharges: A review.

    PubMed

    Judd, Simon; van den Broeke, Leo J P; Shurair, Mohamed; Kuti, Yussuf; Znad, Hussein

    2015-12-15

    The recent literature pertaining to the application of algal photobioreactors (PBRs) to both carbon dioxide mitigation and nutrient abatement is reviewed and the reported data analysed. The review appraises the influence of key system parameters on performance with reference to (a) the absorption and biological fixation of CO2 from gaseous effluent streams, and (b) the removal of nutrients from wastewaters. Key parameters appraised individually with reference to CO2 removal comprise algal speciation, light intensity, mass transfer, gas and hydraulic residence time, pollutant (CO2 and nutrient) loading, biochemical and chemical stoichiometry (including pH), and temperature. Nutrient removal has been assessed with reference to hydraulic residence time and reactor configuration, along with C:nutrient ratios and other factors affecting carbon fixation, and outcomes compared with those reported for classical biological nutrient removal (BNR). Outcomes of the review indicate there has been a disproportionate increase in algal PBR research outputs over the past 5-8 years, with a significant number of studies based on small, bench-scale systems. The quantitative impacts of light intensity and loading on CO2 uptake are highly dependent on the algal species, and also affected by solution chemical conditions such as temperature and pH. Calculations based on available data for biomass growth rates indicate that a reactor CO2 residence time of around 4 h is required for significant CO2 removal. Nutrient removal data indicate residence times of 2-5 days are required for significant nutrient removal, compared with <12 h for a BNR plant. Moreover, the shallow depth of the simplest PBR configuration (the high rate algal pond, HRAP) means that its footprint is at least two orders of magnitude greater than a classical BNR plant. It is concluded that the combined carbon capture/nutrient removal process relies on optimisation of a number of process parameters acting synergistically

  9. Hydrologic processes and nutrient dynamics in a pristine mountain catchment

    USGS Publications Warehouse

    F. Richard Hauer,; Fagre, Daniel B.; Stanford, Jack A.

    2002-01-01

    Nutrient dynamics in watersheds have been used as an ecosystem-level indicator of overall ecosystem function or response to disturbance (e.g. Borman.N et al. 1974, WEBSTER et al. 1992). The examination of nutrients has been evaluated to determine responses to logging practices or other changes in watershed land use. Nutrient dynamics have been related to changing physical and biological characteristics (Mulholl AND 1992, CHESTNUT & McDowell 2000). Herein, the concentrations and dynamics of nitrogen, phosphorus and particulate organic carbon were examined in a large pristine watershed because they are affected by changes in discharge directly from the catchment and after passage through a large oligotrophic lake. 

  10. Nutrients removal and recovery in bioelectrochemical systems: a review.

    PubMed

    Kelly, Patrick T; He, Zhen

    2014-02-01

    Nutrient removal and recovery has received less attention during the development of bioelectrochemical systems (BES) for energy efficient wastewater treatment, but it is a critical issue for sustainable wastewater treatment. Both nitrogen and phosphorus can be removed and/or recovered in a BES through involving biological processes such as nitrification and bioelectrochemical denitrification, the NH4(+)/NH3 couple affected by the electrolyte pH, or precipitating phosphorus compounds in the high-pH zone adjacent a cathode electrode. This paper has reviewed the nutrients removal and recovery in various BES including microbial fuel cells and microbial electrolysis cells, discussed the influence factors and potential problems, and identified the key challenges for nitrogen and phosphorus removal/recovery in a BES. It expects to give an informative overview of the current development, and to encourage more thinking and investigation towards further development of efficient processes for nutrient removal and recovery in a BES.

  11. Recent advances in ophthalmic drug delivery

    PubMed Central

    Kompella, Uday B; Kadam, Rajendra S; Lee, Vincent HL

    2011-01-01

    Topical ocular drug bioavailability is notoriously poor, in the order of 5% or less. This is a consequence of effective multiple barriers to drug entry, comprising nasolacrimal drainage, epithelial drug transport barriers and clearance from the vasculature in the conjunctiva. While sustained drug delivery to the back of the eye is now feasible with intravitreal implants such as Vitrasert™ (~6 months), Retisert™ (~3 years) and Iluvien™ (~3 years), currently there are no marketed delivery systems for long-term drug delivery to the anterior segment of the eye. The purpose of this article is to summarize the resurgence in interest to prolong and improve drug entry from topical administration. These approaches include mucoadhesives, viscous polymer vehicles, transporter-targeted prodrug design, receptor-targeted functionalized nanoparticles, iontophoresis, punctal plug and contact lens delivery systems. A few of these delivery systems might be useful in treating diseases affecting the back of the eye. Their effectiveness will be compared against intravitreal implants (upper bound of effectiveness) and trans-scleral systems (lower bound of effectiveness). Refining the animal model by incorporating the latest advances in microdialysis and imaging technology is key to expanding the knowledge central to the design, testing and evaluation of the next generation of innovative ocular drug delivery systems. PMID:21399724

  12. Agile delivery of protein therapeutics to CNS.

    PubMed

    Yi, Xiang; Manickam, Devika S; Brynskikh, Anna; Kabanov, Alexander V

    2014-09-28

    A variety of therapeutic proteins have shown potential to treat central nervous system (CNS) disorders. Challenge to deliver these protein molecules to the brain is well known. Proteins administered through parenteral routes are often excluded from the brain because of their poor bioavailability and the existence of the blood-brain barrier (BBB). Barriers also exist to proteins administered through non-parenteral routes that bypass the BBB. Several strategies have shown promise in delivering proteins to the brain. This review, first, describes the physiology and pathology of the BBB that underscore the rationale and needs of each strategy to be applied. Second, major classes of protein therapeutics along with some key factors that affect their delivery outcomes are presented. Third, different routes of protein administration (parenteral, central intracerebroventricular and intraparenchymal, intranasal and intrathecal) are discussed along with key barriers to CNS delivery associated with each route. Finally, current delivery strategies involving chemical modification of proteins and use of particle-based carriers are overviewed using examples from literature and our own work. Whereas most of these studies are in the early stage, some provide proof of mechanism of increased protein delivery to the brain in relevant models of CNS diseases, while in few cases proof of concept had been attained in clinical studies. This review will be useful to broad audience of students, academicians and industry professionals who consider critical issues of protein delivery to the brain and aim developing and studying effective brain delivery systems for protein therapeutics.

  13. Agile Delivery of Protein Therapeutics to CNS

    PubMed Central

    Yi, Xiang; Manickam, Devika S.; Brynskikh, Anna; Kabanov, Alexander V.

    2014-01-01

    A variety of therapeutic proteins have shown potential to treat central nervous system (CNS) disorders. Challenge to deliver these protein molecules to the brain is well known. Proteins administered through parenteral routes are often excluded from the brain because of their poor bioavailability and the existence of the blood-brain barrier (BBB). Barriers also exist to proteins administered through non-parenteral routes that bypass the BBB. Several strategies have shown promise in delivering proteins to the brain. This review, first, describes the physiology and pathology of the BBB that underscore the rationale and needs of each strategy to be applied. Second, major classes of protein therapeutics along with some key factors that affect their delivery outcomes are presented. Third, different routes of protein administration (parenteral, central intracerebroventricular and intraparenchymal, intranasal and intrathecal) are discussed along with key barriers to CNS delivery associated with each route. Finally, current delivery strategies involving chemical modification of proteins and use of particle-based carriers are overviewed using examples from literature and our own work. Whereas most of these studies are in the early stage, some provide proof of mechanism of increased protein delivery to the brain in relevant models of CNS diseases, while in few cases proof of concept had been attained in clinical studies. This review will be useful to broad audience of students, academicians and industry professionals who consider critical issues of protein delivery to the brain and aim developing and studying effective brain delivery systems for protein therapeutics. PMID:24956489

  14. Lichen substances prevent lichens from nutrient deficiency.

    PubMed

    Hauck, Markus; Willenbruch, Karen; Leuschner, Christoph

    2009-01-01

    The dibenzofuran usnic acid, a widespread cortical secondary metabolite produced by lichen-forming fungi, was shown to promote the intracellular uptake of Cu(2+) in two epiphytic lichens, Evernia mesomorpha and Ramalina menziesii, from acidic, nutrient-poor bark. Higher Cu(2+) uptake in the former, which produces the depside divaricatic acid in addition to usnic acid, suggests that this depside promotes Cu(2+) uptake. Since Cu(2+) is one of the rarest micronutrients, promotion of Cu(2+) uptake by lichen substances may be crucial for the studied lichens to survive in their nutrient-poor habitats. In contrast, study of the uptake of other metals in E. mesomorpha revealed that the intracellular uptake of Mn(2+), which regularly exceeds potentially toxic concentrations in leachates of acidic tree bark, was partially inhibited by the lichen substances produced by this species. Inhibition of Mn(2+) uptake by lichen substances previously has been demonstrated in lichens. The uptake of Fe(2+), Fe(3+), Mg(2+), and Zn(2+), which fail to reach toxic concentrations in acidic bark at unpolluted sites, although they are more common than Cu(2+), was not affected by lichen substances of E. mesomorpha.

  15. Placental Nutrient Transport and Intrauterine Growth Restriction

    PubMed Central

    Gaccioli, Francesca; Lager, Susanne

    2016-01-01

    Intrauterine growth restriction refers to the inability of the fetus to reach its genetically determined potential size. Fetal growth restriction affects approximately 5–15% of all pregnancies in the United States and Europe. In developing countries the occurrence varies widely between 10 and 55%, impacting about 30 million newborns per year. Besides having high perinatal mortality rates these infants are at greater risk for severe adverse outcomes, such as hypoxic ischemic encephalopathy and cerebral palsy. Moreover, reduced fetal growth has lifelong health consequences, including higher risks of developing metabolic and cardiovascular diseases in adulthood. Numerous reports indicate placental insufficiency as one of the underlying causes leading to altered fetal growth and impaired placental capacity of delivering nutrients to the fetus has been shown to contribute to the etiology of intrauterine growth restriction. Indeed, reduced expression and/or activity of placental nutrient transporters have been demonstrated in several conditions associated with an increased risk of delivering a small or growth restricted infant. This review focuses on human pregnancies and summarizes the changes in placental amino acid, fatty acid, and glucose transport reported in conditions associated with intrauterine growth restriction, such as maternal undernutrition, pre-eclampsia, young maternal age, high altitude and infection. PMID:26909042

  16. Light, nutrients, and herbivore growth in oligotrophic streams

    SciTech Connect

    Hill, Walter R; Smith, John G; Stewart, Arthur J

    2010-02-01

    The light : nutrient hypothesis posits that herbivore growth is increasingly constrained by low food quality as the ratio of light to nutrients increases in aquatic ecosystems. We tested predictions of this hypothesis by examining the effects of large seasonal cycles in light and nutrients on the mineral content of periphyton and the growth rate of a dominant herbivore (the snail Elimia clavaeformis) in two oligotrophic streams. Streambed irradiances in White Oak Creek and Walker Branch (eastern Tennessee, USA) varied dramatically on a seasonal basis due to leaf phenology in the surrounding deciduous forests and seasonal changes in sun angle. Concentrations of dissolved nutrients varied inversely with light, causing light : nitrate and light : phosphate to range almost 100-fold over the course of any individual year. Periphyton nitrogen and phosphorus concentrations were much lower than the concentrations of these elements in snails, and they bottomed out in early spring when streambed irradiances were highest. Snail growth, however, peaked in early spring when light:nutrient ratios were highest and periphyton nutrient concentrations were lowest, Growth was linearly related to primary production (accounting for up to 85% of growth variance in individual years), which in turn was driven by seasonal variation in light. Conceptual models of herbivore growth indicate that growth should initially increase as increasing light levels stimulate primary production, but then level off, and then decrease as the negative effects of decreasing algal nutrient content override the positive effects of increased food production. Our results showed no evidence of an inflection point where increasing ratios of light to nutrients negatively affected growth. Snail growth in these intensively grazed streams is probably unaffected by periphyton nutrient content because exploitative competition for food reduces growth rates to levels where the demand for nitrogen and phosphorus is small

  17. Hydrogel Encapsulation of Cells in Core-Shell Microcapsules for Cell Delivery.

    PubMed

    Nguyen, Duy Khiem; Son, Young Min; Lee, Nae-Eung

    2015-07-15

    A newly designed 3D core-shell microcapsule structure composed of a cell-containing liquid core and an alginate hydrogel shell is fabricated using a coaxial dual-nozzle electrospinning system. Spherical alginate microcapsules are successfully generated with a core-shell structure and less than 300 μm in average diameter using this system. The thickness of the core and shell can be easily controlled by manipulating the core and shell flow rates. Cells encapsulated in core-shell microcapsules demonstrate better cell encapsulation and immune protection than those encapsulated in microbeads. The observation of a high percentage of live cells (≈80%) after encapsulation demonstrates that the voltage applied for generation of microcapsules does not significantly affect the viability of encapsulated cells. The viability of encapsulated cells does not change even after 3 d in culture, which suggests that the core-shell structure with culture medium in the core can maintain high cell survival by providing nutrients and oxygen to all cells. This newly designed core-shell structure can be extended to use in multifunctional platforms not only for delivery of cells but also for factor delivery, imaging, or diagnosis by loading other components in the core or shell.

  18. Stillage processing for nutrient recovery

    SciTech Connect

    Sweeten, J.M.; Coble, C.G.; Egg, R.P.; Lawhon, J.T.; McBee, G.G.; Schelling, G.T.

    1983-06-01

    Stillage from fermentation of grain sorghum and sweet potatoes was processed for dry matter and nutrient recovery by combinations of screw press, vibrating screen, centrifugation, ultrafiltration, and reverse osmosis, yielding up to 98% dry matter removal. For most processes, protein removal equaled or exceeded dry matter removal.

  19. NanoART, neuroAIDS and CNS drug delivery

    PubMed Central

    Nowacek, Ari; Gendelman, Howard E

    2009-01-01

    A broad range of nanomedicines is being developed to improve drug delivery for CNS disorders. The structure of the blood–brain barrier (BBB), the presence of efflux pumps and the expression of metabolic enzymes pose hurdles for drug-brain entry. Nanoformulations can circumvent the BBB to improve CNS-directed drug delivery by affecting such pumps and enzymes. Alternatively, they can be optimized to affect their size, shape, and protein and lipid coatings to facilitate drug uptake, release and ingress across the barrier. This is important as the brain is a sanctuary for a broad range of pathogens including HIV-1. Improved drug delivery to the CNS would affect pharmacokinetic and drug biodistribution properties. This article focuses on how nanotechnology can serve to improve the delivery of antiretroviral medicines, termed nanoART, across the BBB and affect the biodistribution and clinical benefit for HIV-1 disease. PMID:19572821

  20. Nutrient budgets in the subtropical ocean gyres dominated by lateral transport

    NASA Astrophysics Data System (ADS)

    Letscher, Robert T.; Primeau, François; Moore, J. Keith

    2016-11-01

    Ocean circulation replenishes surface nutrients depleted by biological production and export. Vertical processes are thought to dominate, but estimated vertical nutrient fluxes are insufficient to explain observed net productivity in the subtropical ocean gyres. Lateral inputs help balance the North Atlantic nutrient budget, but their importance for other gyres has not been demonstrated. Here we use an ocean model that couples circulation and ecosystem dynamics to show that lateral transport and biological uptake of inorganic and organic forms of nitrogen and phosphorus from the gyre margins exceeds the vertical delivery of nutrients, supplying 24-36% of the nitrogen and 44-67% of the phosphorus required to close gyre nutrient budgets. At the Bermuda and Hawaii time-series sites, nearly half of the annual lateral supply by lateral transport occurs during the summer-to-fall stratified period, helping explain seasonal patterns of inorganic carbon drawdown and nitrogen fixation. Our study confirms the importance of upper-ocean lateral nutrient transport for understanding the biological cycles of carbon and nutrients in the ocean's largest biome.

  1. Pathogen infection drives patterns of nutrient resorption in citrus plants

    PubMed Central

    Cao, Jirong; Cheng, Chunzhen; Yang, Junjie; Wang, Qibing

    2015-01-01

    Nutrient resorption processes in the plants infected by pathogen remain poorly understood. Huanglongbing (HLB) is a destructive disease of citrus. HLB-pathogen ‘Candidatus Liberibacter asiaticus’ grows specifically in the phloem of hosts and may cause problems in the plant vascular system after infection. Therefore, it brings a great concern about the phloem nutrient transport and nutrient intra-cycling in HLB-affected plants. We investigated the effects of ‘Ca. L. asiaticus’ infection on nitrogen (N) and phosphorus (P) concentrations and resorption in different citrus species (i.e. Citrus reticulata, Citrus limon and Citrus maxima). HLB-pathogen infection had distinctive impacts on nutrient resorption in different species. P resorption efficiency substantially decreased in infected C. reticulata plants relative to the healthy plants in summer, which may account for the marked decrease in the average fruit yield. P resorption was more efficient in infected C. limon plants than in the healthy plants. However, for C. maxima plants, HLB had no significant effects on N:P ratio in live leaves and resorption efficiency as well as on fruit yield. Keeping efficient internal nutrient cycling can be a strategy of citrus species being tolerant to HLB. PMID:26419510

  2. Pathogen infection drives patterns of nutrient resorption in citrus plants.

    PubMed

    Cao, Jirong; Cheng, Chunzhen; Yang, Junjie; Wang, Qibing

    2015-09-30

    Nutrient resorption processes in the plants infected by pathogen remain poorly understood. Huanglongbing (HLB) is a destructive disease of citrus. HLB-pathogen 'Candidatus Liberibacter asiaticus' grows specifically in the phloem of hosts and may cause problems in the plant vascular system after infection. Therefore, it brings a great concern about the phloem nutrient transport and nutrient intra-cycling in HLB-affected plants. We investigated the effects of 'Ca. L. asiaticus' infection on nitrogen (N) and phosphorus (P) concentrations and resorption in different citrus species (i.e. Citrus reticulata, Citrus limon and Citrus maxima). HLB-pathogen infection had distinctive impacts on nutrient resorption in different species. P resorption efficiency substantially decreased in infected C. reticulata plants relative to the healthy plants in summer, which may account for the marked decrease in the average fruit yield. P resorption was more efficient in infected C. limon plants than in the healthy plants. However, for C. maxima plants, HLB had no significant effects on N:P ratio in live leaves and resorption efficiency as well as on fruit yield. Keeping efficient internal nutrient cycling can be a strategy of citrus species being tolerant to HLB.

  3. Carrot, Corn, Lettuce and Soybean Nutrient Contents are ...

    EPA Pesticide Factsheets

    Biochar, the carbon-rich material remaining after pyrolysis of cellulosic and manure feedstocks, has the potential as a soil amendment to sequester carbon and to improve soil water-holding and nutrient properties- thereby enhancing plant growth. However, biochar produced from some feedstocks also could adversely affect crop quality by changing soil pH and reducing nutrients (e.g., Ca, K, Mg, N, Na, and P) in plant tissues. To evaluate effects of biochar on the nutrient quality of four crops, we conducted a greenhouse study using pots with: carrot (Daucus carota cv. Tendersweet), corn (Zea mays, cv. Golden Bantam), lettuce (Lactuca sativa, cv. Black-Seeded Simpson) and soybean (Glycine max cv. Viking 2265). Plants were grown in one of two South Carolina sandy Coastal Plain soils (Norfolk and Coxville Soil Series), along with biochar (1% by weight) produced from pine chips (PC), poultry litter (PL), swine solids (SS), switchgrass (SG), and two blends of pine chips plus poultry litter (PC/PL, 50/50% and 80/20%). Each of the feedstocks and feedstock blends was pyrolyzed at 350, 500, and 700 ̊ C to produce the biochar used to amend the Norfolk and Coxville soils. Effects of biochar on leaf nutrients (% dry weight) statistically varied with species, soil, feedstock and temperature and nutrient. For carrot and lettuce, the PL, PL/PC, and SS biochars generally decreased leaf N, Ca, Mg, and P; while PL and PL/PC increased K and Na. Biochars had little effect on lea

  4. Less is more: Nutrient limitation induces cross-talk of nutrient sensing pathways with NAD+ homeostasis and contributes to longevity

    PubMed Central

    TSANG, Felicia; LIN, Su-Ju

    2016-01-01

    Nutrient sensing pathways and their regulation grant cells control over their metabolism and growth in response to changing nutrients. Factors that regulate nutrient sensing can also modulate longevity. Reduced activity of nutrient sensing pathways such as glucose-sensing PKA, nitrogen-sensing TOR and S6 kinase homolog Sch9 have been linked to increased life span in the yeast, Saccharomyces cerevisiae, and higher eukaryotes. Recently, reduced activity of amino acid sensing SPS pathway was also shown to increase yeast life span. Life span extension by reduced SPS activity requires enhanced NAD+ (nicotinamide adenine dinucleotide, oxidized form) and nicotinamide riboside (NR, a NAD+ precursor) homeostasis. Maintaining adequate NAD+ pools has been shown to play key roles in life span extension, but factors regulating NAD+ metabolism and homeostasis are not completely understood. Recently, NAD+ metabolism was also linked to the phosphate (Pi)-sensing PHO pathway in yeast. Canonical PHO activation requires Pi-starvation. Interestingly, NAD+ depletion without Pi-starvation was sufficient to induce PHO activation, increasing NR production and mobilization. Moreover, SPS signaling appears to function in parallel with PHO signaling components to regulate NR/NAD+ homeostasis. These studies suggest that NAD+ metabolism is likely controlled by and/or coordinated with multiple nutrient sensing pathways. Indeed, cross-regulation of PHO, PKA, TOR and Sch9 pathways was reported to potentially affect NAD+ metabolism; though detailed mechanisms remain unclear. This review discusses yeast longevity-related nutrient sensing pathways and possible mechanisms of life span extension, regulation of NAD+ homeostasis, and cross-talk among nutrient sensing pathways and NAD+ homeostasis. PMID:27683589

  5. Therapeutic perspectives of epigenetically active nutrients.

    PubMed

    Remely, M; Lovrecic, L; de la Garza, A L; Migliore, L; Peterlin, B; Milagro, F I; Martinez, A J; Haslberger, A G

    2015-06-01

    Many nutrients are known for a wide range of activities in prevention and alleviation of various diseases. Recently, their potential role in regulating human health through effects on epigenetics has become evident, although specific mechanisms are still unclear. Thus, nutriepigenetics/nutriepigenomics has emerged as a new and promising field in current epigenetics research in the past few years. In particular, polyphenols, as part of the central dynamic interaction between the genome and the environment with specificity at physiological concentrations, are well known to affect mechanisms underlying human health. This review summarizes the effects of dietary compounds on epigenetic mechanisms in the regulation of gene expression including expression of enzymes and other molecules responsible for drug absorption, distribution, metabolism and excretion in cancer, metabolic syndrome, neurodegenerative disorders and hormonal dysfunction.

  6. Therapeutic perspectives of epigenetically active nutrients

    PubMed Central

    Remely, M; Lovrecic, L; de la Garza, A L; Migliore, L; Peterlin, B; Milagro, F I; Martinez, A J; Haslberger, A G

    2015-01-01

    Many nutrients are known for a wide range of activities in prevention and alleviation of various diseases. Recently, their potential role in regulating human health through effects on epigenetics has become evident, although specific mechanisms are still unclear. Thus, nutriepigenetics/nutriepigenomics has emerged as a new and promising field in current epigenetics research in the past few years. In particular, polyphenols, as part of the central dynamic interaction between the genome and the environment with specificity at physiological concentrations, are well known to affect mechanisms underlying human health. This review summarizes the effects of dietary compounds on epigenetic mechanisms in the regulation of gene expression including expression of enzymes and other molecules responsible for drug absorption, distribution, metabolism and excretion in cancer, metabolic syndrome, neurodegenerative disorders and hormonal dysfunction. PMID:25046997

  7. Breastfeeding After Cesarean Delivery

    MedlinePlus

    ... Breastfeeding Crying & Colic Diapers & Clothing Feeding & Nutrition Preemie Sleep Teething & Tooth Care Toddler Preschool Gradeschool Teen Young Adult Healthy Children > Ages & Stages > Baby > Breastfeeding > Breastfeeding After Cesarean Delivery Ages & Stages ...

  8. Transdermal delivery of proteins.

    PubMed

    Kalluri, Haripriya; Banga, Ajay K

    2011-03-01

    Transdermal delivery of peptides and proteins avoids the disadvantages associated with the invasive parenteral route of administration and other alternative routes such as the pulmonary and nasal routes. Since proteins have a large size and are hydrophilic in nature, they cannot permeate passively across the skin due to the stratum corneum which allows the transport of only small lipophilic drug molecules. Enhancement techniques such as chemical enhancers, iontophoresis, microneedles, electroporation, sonophoresis, thermal ablation, laser ablation, radiofrequency ablation and noninvasive jet injectors aid in the delivery of proteins by overcoming the skin barrier in different ways. In this review, these enhancement techniques that can enable the transdermal delivery of proteins are discussed, including a discussion of mechanisms, sterility requirements, and commercial development of products. Combination of enhancement techniques may result in a synergistic effect allowing increased protein delivery and these are also discussed.

  9. Delivery of twins.

    PubMed

    Hofmeyr, G J; Drakeley, A J

    1998-03-01

    The delivery of twins presents considerable challenges to the obstetric team, particularly in terms of decision-making, technical skills required and the need to respond quickly to changing circumstances. There is a serious lack of sound evidence upon which to base decisions concerning the method of delivery of twins. The trend towards the routine use of caesarean section is not supported by evidence of improved outcome for the infants, while maternal outcome is compromised. Specific circumstances that may have a bearing on the need for caesarean section include gestational age, presentation of the twins and chorionicity/amnionicity. Caesarean section does not eliminate the chance of fetal trauma during delivery, particularly for premature twins. The techniques of twin delivery, whether vaginal or by caesarean section, require thorough preparation for all possible eventualities, and skilled teamwork. Particular attention should be paid to emotional needs during labour, birth and afterwards, of the parents of twins.

  10. Delivery by Cesarean Section

    MedlinePlus

    ... Español Text Size Email Print Share Delivery by Cesarean Section Page Content Article Body More than one mother in three gives birth by Cesarean section in the United States (it is also called ...

  11. Project Delivery Methods.

    ERIC Educational Resources Information Center

    Dolan, Thomas G.

    2003-01-01

    Describes project delivery methods that are replacing the traditional Design/Bid/Build linear approach to the management, design, and construction of new facilities. These variations can enhance construction management and teamwork. (SLD)

  12. EPA Announces Nutrient Recycling Challenge Winners

    EPA Pesticide Factsheets

    WASHINGTON - Today, the U.S. Environmental Protection Agency (EPA) announced the winners of Phase I of the Nutrient Recycling Challenge-a competition to develop affordable technologies to recycle nutrients from livestock manure. The winners received

  13. A Geographic Information System approach to modeling nutrient and sediment transport

    SciTech Connect

    Levine, D.A.; Hunsaker, C.T.; Beauchamp, J.J.; Timmins, S.P.

    1993-02-01

    The objective of this study was to develop a water quality model to quantify nonpoint-source (NPS) pollution that uses a geographic information system (GIS) to link statistical modeling of nutrient and sediment delivery with the spatial arrangement of the parameters that drive the model. The model predicts annual nutrient and sediment loading and was developed, calibrated, and tested on 12 watersheds within the Lake Ray Roberts drainage basin in north Texas. Three physiographic regions are represented by these watersheds, and model success, as measured by the accuracy of load estimates, was compared within and across these regions.

  14. From plant surface to plant metabolism: the uncertain fate of foliar-applied nutrients

    PubMed Central

    Fernández, Victoria; Brown, Patrick H.

    2013-01-01

    The application of agrochemical sprays to the aerial parts of crop plants is an important agricultural practice world-wide. While variable effectiveness is often seen in response to foliar treatments, there is abundant evidence showing the beneficial effect of foliar fertilizers in terms of improving the metabolism, quality, and yields of crops. This mini-review is focused on the major bottlenecks associated with the uptake and translocation of foliar-applied nutrient solutions. A better understanding of the complex scenario surrounding the ultimate delivery of foliar-applied nutrients to sink cells and organs is essential for improving the effectiveness and performance of foliar fertilizers. PMID:23914198

  15. From plant surface to plant metabolism: the uncertain fate of foliar-applied nutrients.

    PubMed

    Fernández, Victoria; Brown, Patrick H

    2013-01-01

    The application of agrochemical sprays to the aerial parts of crop plants is an important agricultural practice world-wide. While variable effectiveness is often seen in response to foliar treatments, there is abundant evidence showing the beneficial effect of foliar fertilizers in terms of improving the metabolism, quality, and yields of crops. This mini-review is focused on the major bottlenecks associated with the uptake and translocation of foliar-applied nutrient solutions. A better understanding of the complex scenario surrounding the ultimate delivery of foliar-applied nutrients to sink cells and organs is essential for improving the effectiveness and performance of foliar fertilizers.

  16. Nutrient and biological conditions of selected small streams in the Edwards Plateau, central Texas, 2005-06, and implications for development of nutrient criteria

    USGS Publications Warehouse

    Mabe, Jeffrey A.

    2007-01-01

    During the summers of 2005 and 2006 the U.S. Geological Survey, in cooperation with the Texas Commission on Environmental Quality, evaluated nutrient and biological conditions in small streams in parts of the Edwards Plateau of Central Texas. Land-cover analysis was used to select 15 small streams that represented a gradient of conditions with the potential to affect nutrient concentrations across the study area, which comprises two of four subregions of the Edwards Plateau ecoregion. All 15 streams were sampled for water properties, nutrients, algae, benthic invertebrates, and fish in summer 2005, and eight streams were resampled in summer 2006. Streams that did not receive wastewater effluent had relatively low nutrient concentrations and were classified as oligotrophic; streams receiving wastewater effluent had relatively high nutrient concentrations and were classified as eutrophic. Nutrient concentrations measured in the least-disturbed streams closely matched the U.S. Environmental Protection Agency nutrient criteria recommendations based on estimated reference concentrations. Nitrogen/phosphorus ratios indicated streams not affected by wastewater effluent might be limited by phosphorus concentrations. Algal indicators of nutrient condition were closely related to dissolved nitrogen concentrations and streamflow conditions. Ambient dissolved nitrogen concentrations (nitrite plus nitrate) were positively correlated with benthic algal chlorophyll-a concentrations. The correlation of benthic algal chlorophyll-a with instantaneous nitrite plus nitrate load was stronger than correlations with ambient nutrients. Increased nutrient concentrations were associated with increased macroalgae cover, wider diel dissolved oxygen ranges, and reduced diel dissolved oxygen minimums. Benthic invertebrate aquatic life use scores generally were classified as High to Exceptional in study streams despite the influence of urbanization or wastewater effluent. Reductions in aquatic

  17. Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens.

    PubMed

    Gharajehdaghipour, Tazarve; Roth, James D; Fafard, Paul M; Markham, John H

    2016-04-05

    Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ(15)N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra.

  18. Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens

    NASA Astrophysics Data System (ADS)

    Gharajehdaghipour, Tazarve; Roth, James D.; Fafard, Paul M.; Markham, John H.

    2016-04-01

    Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ15N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra.

  19. Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens

    PubMed Central

    Gharajehdaghipour, Tazarve; Roth, James D.; Fafard, Paul M.; Markham, John H.

    2016-01-01

    Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ15N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra. PMID:27045973

  20. Phytoplankton Diversity Effects on Community Biomass and Stability along Nutrient Gradients in a Eutrophic Lake.

    PubMed

    Tian, Wang; Zhang, Huayong; Zhao, Lei; Zhang, Feifan; Huang, Hai

    2017-01-20

    The relationship between biodiversity and ecosystem functioning is a central issue in ecology, but how this relationship is affected by nutrient stress is still unknown. In this study, we analyzed the phytoplankton diversity effects on community biomass and stability along nutrient gradients in an artificial eutrophic lake. Four nutrient gradients, varying from slightly eutrophic to highly eutrophic states, were designed by adjusting the amount of polluted water that flowed into the lake. Mean phytoplankton biomass, species richness, and Shannon diversity index all showed significant differences among the four nutrient gradients. Phytoplankton community biomass was correlated with diversity (both species richness and Shannon diversity index), varying from positive to negative along the nutrient gradients. The influence of phytoplankton species richness on resource use efficiency (RUE) also changed from positive to negative along the nutrient gradients. However, the influence of phytoplankton Shannon diversity on RUE was not significant. Both phytoplankton species richness and Shannon diversity had a negative influence on community turnover (measured as community dissimilarity), i.e., a positive diversity-stability relationship. Furthermore, phytoplankton spatial stability decreased along the nutrient gradients in the lake. With increasing nutrient concentrations, the variability (standard deviation) of phytoplankton community biomass increased more rapidly than the average total biomass. Results in this study will be helpful in understanding the phytoplankton diversity effects on ecosystem functioning and how these effects are influenced by nutrient conditions in aquatic ecosystems.

  1. The effects of leaf litter nutrient pulses on Alliaria petiolata performance

    PubMed Central

    Carr, David E.

    2015-01-01

    Nutrient pulses can facilitate species establishment and spread in new habitats, particularly when one species more effectively uses that nutrient pulse. Biological differences in nutrient acquisition between native and exotic species may facilitate invasions into a variety of habitats including deciduous forest understories. Alliaria petiolata (Bieb.) Cavara & Grande is an important invader of deciduous forest understories throughout much of North America. These understory communities contain many species which perform the majority of their growth and reproduction before canopy closure in spring. Because A. petiolata is a wintergreen biennial that can be active during autumn and winter, it may utilize nutrients released from decaying leaf litter before its competitors. To investigate this we manipulated the timing of leaf litter addition (fall or spring) and experimentally simulated the nutrient pulse from decaying leaves using artificial fertilizer. To determine whether A. petiolata affected the abundance of understory competitors, we also removed A. petiolata from one treatment. A. petiolata that received early nutrients exhibited greater growth. Treatments receiving fall leaf litter or artificial nutrients had greater A. petiolata adult biomass than plots receiving spring nutrient additions (leaf litter or artificial nutrients). However, fall leaf litter addition had no effect on the richness of competitor species. Thus, wintergreen phenology may contribute to the spread of A. petiolata through deciduous forest understories, but may not explain community-level impacts of A. petiolata in deciduous forests. PMID:26312176

  2. Plant-herbivore-decomposer stoichiometric mismatches and nutrient cycling in ecosystems.

    PubMed

    Cherif, Mehdi; Loreau, Michel

    2013-03-07

    Plant stoichiometry is thought to have a major influence on how herbivores affect nutrient availability in ecosystems. Most conceptual models predict that plants with high nutrient contents increase nutrient excretion by herbivores, in turn raising nutrient availability. To test this hypothesis, we built a stoichiometrically explicit model that includes a simple but thorough description of the processes of herbivory and decomposition. Our results challenge traditional views of herbivore impacts on nutrient availability in many ways. They show that the relationship between plant nutrient content and the impact of herbivores predicted by conceptual models holds only at high plant nutrient contents. At low plant nutrient contents, the impact of herbivores is mediated by the mineralization/immobilization of nutrients by decomposers and by the type of resource limiting the growth of decomposers. Both parameters are functions of the mismatch between plant and decomposer stoichiometries. Our work provides new predictions about the impacts of herbivores on ecosystem fertility that depend on critical interactions between plant, herbivore and decomposer stoichiometries in ecosystems.

  3. Phytoplankton Diversity Effects on Community Biomass and Stability along Nutrient Gradients in a Eutrophic Lake

    PubMed Central

    Tian, Wang; Zhang, Huayong; Zhao, Lei; Zhang, Feifan; Huang, Hai

    2017-01-01

    The relationship between biodiversity and ecosystem functioning is a central issue in ecology, but how this relationship is affected by nutrient stress is still unknown. In this study, we analyzed the phytoplankton diversity effects on community biomass and stability along nutrient gradients in an artificial eutrophic lake. Four nutrient gradients, varying from slightly eutrophic to highly eutrophic states, were designed by adjusting the amount of polluted water that flowed into the lake. Mean phytoplankton biomass, species richness, and Shannon diversity index all showed significant differences among the four nutrient gradients. Phytoplankton community biomass was correlated with diversity (both species richness and Shannon diversity index), varying from positive to negative along the nutrient gradients. The influence of phytoplankton species richness on resource use efficiency (RUE) also changed from positive to negative along the nutrient gradients. However, the influence of phytoplankton Shannon diversity on RUE was not significant. Both phytoplankton species richness and Shannon diversity had a negative influence on community turnover (measured as community dissimilarity), i.e., a positive diversity–stability relationship. Furthermore, phytoplankton spatial stability decreased along the nutrient gradients in the lake. With increasing nutrient concentrations, the variability (standard deviation) of phytoplankton community biomass increased more rapidly than the average total biomass. Results in this study will be helpful in understanding the phytoplankton diversity effects on ecosystem functioning and how these effects are influenced by nutrient conditions in aquatic ecosystems. PMID:28117684

  4. Nutrient quality of fast food kids meals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exposure of children to kids’ meals at fast food restaurants is high; however, the nutrient quality of such meals has not been systematically assessed. We assessed the nutrient quality of fast food meals marketed to young children, i.e., "kids meals". The nutrient quality of kids’ meals was assessed...

  5. Automated nutrient analyses in seawater

    SciTech Connect

    Whitledge, T.E.; Malloy, S.C.; Patton, C.J.; Wirick, C.D.

    1981-02-01

    This manual was assembled for use as a guide for analyzing the nutrient content of seawater samples collected in the marine coastal zone of the Northeast United States and the Bering Sea. Some modifications (changes in dilution or sample pump tube sizes) may be necessary to achieve optimum measurements in very pronounced oligotrophic, eutrophic or brackish areas. Information is presented under the following section headings: theory and mechanics of automated analysis; continuous flow system description; operation of autoanalyzer system; cookbook of current nutrient methods; automated analyzer and data analysis software; computer interfacing and hardware modifications; and trouble shooting. The three appendixes are entitled: references and additional reading; manifold components and chemicals; and software listings. (JGB)

  6. Spectral Quantitation Of Hydroponic Nutrients

    NASA Technical Reports Server (NTRS)

    Schlager, Kenneth J.; Kahle, Scott J.; Wilson, Monica A.; Boehlen, Michelle

    1996-01-01

    Instrument continuously monitors hydroponic solution by use of absorption and emission spectrometry to determine concentrations of principal nutrients, including nitrate, iron, potassium, calcium, magnesium, phosphorus, sodium, and others. Does not depend on extraction and processing of samples, use of such surrograte parameters as pH or electrical conductivity for control, or addition of analytical reagents to solution. Solution not chemically altered by analysis and can be returned to hydroponic process stream after analysis.

  7. High Levels of Dietary Supplement Vitamins A, C and E are Absorbed in the Small Intestine and Protect Nutrient Transport Against Chronic Gamma Irradiation

    PubMed Central

    Azzam, Edouard I.; Ferraris, Ronaldo P.; Howell, Roger W.

    2015-01-01

    We examined nutrient transport in the intestines of mice exposed to chronic low-LET 137Cs gamma rays. The mice were whole-body irradiated for 3 days at dose rates of 0, 0.13 and 0.20 Gy/h, for total dose delivery of 0, 9.6 or 14.4 Gy, respectively. The mice were fed either a control diet or a diet supplemented with high levels of vitamins A, C and E. Our results showed that nutrient transport was perturbed by the chronic irradiation conditions. However, no apparent alteration of the macroscopic intestinal structures of the small intestine were observed up to day 10 after initiating irradiation. Jejunal fructose uptake measured in vitro was strongly affected by the chronic irradiation, whereas uptake of proline, carnosine and the bile acid taurocholate in the ileum was less affected. D-glucose transport did not appear to be inhibited significantly by either 9.6 or 14.4 Gy exposure. In the 14.4 Gy irradiated groups, the diet supplemented with high levels of vitamins A, C and E increased intestinal transport of fructose compared to the control diet (day 10; t test, P = 0.032), which correlated with elevated levels of vitamins A, C and E in the plasma and jejunal enterocytes. Our earlier studies with mice exposed acutely to 137Cs gamma rays demonstrated significant protection for transport of fructose, glucose, proline and carnosine. Taken together, these results suggest that high levels of vitamins A, C and E dietary supplements help preserve intestinal nutrient transport when intestines are irradiated chronically or acutely with low-LET gamma rays. PMID:26484399

  8. High Levels of Dietary Supplement Vitamins A, C and E are Absorbed in the Small Intestine and Protect Nutrient Transport Against Chronic Gamma Irradiation.

    PubMed

    Roche, Marjolaine; Neti, Prasad V S V; Kemp, Francis W; Azzam, Edouard I; Ferraris, Ronaldo P; Howell, Roger W

    2015-11-01

    We examined nutrient transport in the intestines of mice exposed to chronic low-LET 137Cs gamma rays. The mice were whole-body irradiated for 3 days at dose rates of 0, 0.13 and 0.20 Gy/h, for total dose delivery of 0, 9.6 or 14.4 Gy, respectively. The mice were fed either a control diet or a diet supplemented with high levels of vitamins A, C and E. Our results showed that nutrient transport was perturbed by the chronic irradiation conditions. However, no apparent alteration of the macroscopic intestinal structures of the small intestine were observed up to day 10 after initiating irradiation. Jejunal fructose uptake measured in vitro was strongly affected by the chronic irradiation, whereas uptake of proline, carnosine and the bile acid taurocholate in the ileum was less affected. D-glucose transport did not appear to be inhibited significantly by either 9.6 or 14.4 Gy exposure. In the 14.4 Gy irradiated groups, the diet supplemented with high levels of vitamins A, C and E increased intestinal transport of fructose compared to the control diet (day 10; t test, P = 0.032), which correlated with elevated levels of vitamins A, C and E in the plasma and jejunal enterocytes. Our earlier studies with mice exposed acutely to 137Cs gamma rays demonstrated significant protection for transport of fructose, glucose, proline and carnosine. Taken together, these results suggest that high levels of vitamins A, C and E dietary supplements help preserve intestinal nutrient transport when intestines are irradiated chronically or acutely with low-LET gamma rays.

  9. Silk constructs for delivery of muskuloskeletal therapeutics

    PubMed Central

    Meinel, Lorenz; Kaplan, David L.

    2012-01-01

    Silk fibroin (SF) is a biopolymer with distinguishing features from many other bio- as well as synthetic polymers. From a biomechanical and drug delivery perspective, SF combines remarkable versatility for scaffolding (solid implants, hydrogels, threads, solutions), with advanced mechanical properties and good stabilization and controlled delivery of entrapped protein and small molecule drugs, respectively. It is this combination of mechanical and pharmaceutical features which render SF so exciting for biomedical applications. his pattern along with the versatility of this biopolymer have been translated into progress for musculoskeletal applications. We review the use and potential of silk fibroin for systemic and localized delivery of therapeutics in diseases affecting the musculoskeletal system. We also present future directions for this biopolymer as well as the necessary research and development steps for their achievement. PMID:22522139

  10. Collagen-coated microparticles in drug delivery.

    PubMed

    Sehgal, Praveen Kumar; Srinivasan, Aishwarya

    2009-07-01

    Advantages of drug-incorporated collagen particles have been described for the controlled delivery system for therapeutic actions. The attractiveness of collagen lies in its low immunogenicity and high biocompatibility. It is also recognized by the body as a natural constituent rather than a foreign body. Our research and development efforts are focused towards addressing some of the limitations of collagen, like the high viscosity of an aqueous phase, nondissolution in neutral pH buffers, thermal instability (denaturation) and biodegradability, to make it an ideal material for drug delivery with particular reference to microparticles. These limitations could be overcome by making collagen conjugates with other biomaterials or chemically modifying collagen monomer without affecting its triple helical conformation and maintaining its native properties. This article highlights collagen microparticles' present status as a carrier in drug delivery.

  11. Intravenous drug delivery in neonates: lessons learnt.

    PubMed

    Sherwin, Catherine M T; Medlicott, Natalie J; Reith, David M; Broadbent, Roland S

    2014-06-01

    Intravenous drug administration presents a series of challenges that relate to the pathophysiology of the neonate and intravenous infusion systems in neonates. These challenges arise from slow intravenous flow rates, small drug volume, dead space volume and limitations on the flush volume in neonates. While there is a reasonable understanding of newborn pharmacokinetics, an appreciation of the substantial delay and variability in the rate of drug delivery from the intravenous line is often lacking. This can lead to difficulties in accurately determining the pharmacokinetic and pharmacodynamic relationship of drugs in the smallest patients. The physical variables that affect the passage of drugs through neonatal lines need to be further explored in order to improve our understanding of their impact on the delivery of drugs by this route in neonates. Through careful investigation, the underlying causes of delayed drug delivery may be identified and administration protocols can then be modified to ensure predictable, appropriate drug input kinetics.

  12. Nutrients in the Atlantic thermocline

    NASA Astrophysics Data System (ADS)

    Kawase, M.; Sarmiento, J. L.

    1985-01-01

    A set of maps are presented of nutrient distribution on isopycnal surfaces in the North and tropical Atlantic Ocean main thermocline. The data used in producing these maps are from the Transient Tracers in the Oceans (TTO) North Atlantic Study and Tropical Atlantic Study, an associated German study (Meteor 56/5), two cross-Atlantic sections from cruise 109 of the Atlantis II, and the GEOSECS program. The nutrient distributions reflect primarily the sources at the northern and southern outcrops of the isopycnal surfaces, the in situ regeneration due to decomposition of sinking organic materials, and the interior physical processes as inferred from thermocline models and the distribution of conservative properties such as salinity. However, silica also exhibits behavior that cannot be explained by in situ regeneration. A simple phenomenological model suggests that cross-isopycnal advection and mixing in the equatorial region may play an important role in the nutrient dynamics. These data should prove of great value in constraining models of physical as well as biogeochemical processes.

  13. Nutrient contributions to the Santa Barbara Channel, California, from the ephemeral Santa Clara River

    USGS Publications Warehouse

    Warrick, J.A.; Washburn, L.; Brzezinski, Mark A.; Siegel, D.A.

    2005-01-01

    The Santa Clara River delivers nutrient rich runoff to the eastern Santa Barbara Channel during brief (???1-3 day) episodic events. Using both river and oceanographic measurements, we evaluate river loading and dispersal of dissolved macronutrients (silicate, inorganic N and P) and comment on the biological implications of these nutrient contributions. Both river and ocean observations suggest that river nutrient concentrations are inversely related to river flow rates. Land use is suggested to influence these concentrations, since runoff from a subwatershed with substantial agriculture and urban areas had much higher nitrate than runoff from a wooded subwatershed. During runoff events, river nutrients were observed to conservatively mix into the buoyant, surface plume immediately seaward of the Santa Clara River mouth. Dispersal of these river nutrients extended 10s of km into the channel. Growth of phytoplankton and nutrient uptake was low during our observations (1-3 days following runoff), presumably due to the very low light levels resulting from high turbidity. However, nutrient quality of runoff (Si:N:P = 16:5:1) was found to be significantly different than upwelling inputs (13:10:1), which may influence different algal responses once sediments settle. Evaluation of total river nitrate loads suggests that most of the annual river nutrient fluxes to the ocean occur during the brief winter flooding events. Wet winters (such as El Nin??o) contribute nutrients at rates approximately an order-of-magnitude greater than "average" winters. Although total river nitrate delivery is considerably less than that supplied by upwelling, the timing and location of these types of events are very different, with river discharge (upwelling) occurring predominantly in the winter (summer) and in the eastern (western) channel. ?? 2004 Elsevier Ltd. All rights reserved.

  14. Chitosan-Based Multifunctional Platforms for Local Delivery of Therapeutics

    PubMed Central

    Hong, Seong-Chul; Yoo, Seung-Yup; Kim, Hyeongmin; Lee, Jaehwi

    2017-01-01

    Chitosan has been widely used as a key biomaterial for the development of drug delivery systems intended to be administered via oral and parenteral routes. In particular, chitosan-based microparticles are the most frequently employed delivery system, along with specialized systems such as hydrogels, nanoparticles and thin films. Based on the progress made in chitosan-based drug delivery systems, the usefulness of chitosan has further expanded to anti-cancer chemoembolization, tissue engineering, and stem cell research. For instance, chitosan has been used to develop embolic materials designed to efficiently occlude the blood vessels by which the oxygen and nutrients are supplied. Indeed, it has been reported to be a promising embolic material. For better anti-cancer effect, embolic materials that can locally release anti-cancer drugs were proposed. In addition, a complex of radioactive materials and chitosan to be locally injected into the liver has been investigated as an efficient therapeutic tool for hepatocellular carcinoma. In line with this, a number of attempts have been explored to use chitosan-based carriers for the delivery of various agents, especially to the site of interest. Thus, in this work, studies where chitosan-based drug delivery systems have successfully been used for local delivery will be presented along with future perspectives. PMID:28257059

  15. Nutrient Cycling in Piermont Marsh

    NASA Astrophysics Data System (ADS)

    Diaz, K.; Reyes, N.; Gribbin, S.; Newton, R.; Laporte, N.; Trivino, G.; Ortega, J.; McKee, K.; Sambrotto, R.

    2011-12-01

    We investigate the cycling of nutrients through a brackish tidal wetland about 40 km north of Manhattan in the Hudson River estuary. As part of a long-term ecological study of Piermont Marsh, a NOAA reference wetland managed by the NY State DEC, we are measuring dissolved inorganic nutrients on the Marsh surface and its drainage channels. The marsh occupies 400 acres along the southwest corner of Haverstraw Bay with approximately 2 km frontage to the estuary. It is supplied with nutrient-rich water and drained primarily along several tidal creeks and the hundreds of rivulets that feed them. During most tidal cycles the silty berm bounding the marsh is not topped. Human influence in the marsh's surrounding area has had profound effects, one of the most fundamental of which has been the shift from native grass species, predominantly Spartina alterniflora, to an invasive genotype of common reed, Phragmites australis. Along with this shift there have been changes in the root bed, the effective marsh interior and berm heights, the hydroperiod and, as a result, the ability of the marsh to be utilized by various types of Hudson estuary fish. The vegetative shift is believed to be anthropogenic, but the connection is not well understood, and it is not known what role biogeochemical perturbations are playing. We present two field seasons of nitrate, phosphate and silicate measurements from Sparkill Creek, a freshwater stream draining the surrounding highlands constitutes the northern boundary, two tidally driven creeks transect the Marsh from West to East: the Crumkill and an unnamed creek we have dubbed the "Tidal", Ludlow Ditch, a no-longer-maintained drainage channel grading gently from the northern part of the marsh to the South terminates in a wide tidal outlet that is its southern boundary. Net tidal cycle fluxes and fluxes resulting from runoff events are presented. Deviations from Redfield ratios and limiting nutrients are analyzed. Piermont Marsh data is compared

  16. Nutrient Enrichment Coupled with Sedimentation Favors Sea Anemones over Corals

    PubMed Central

    Liu, Pi-Jen; Hsin, Min-Chieh; Huang, Yen-Hsun; Fan, Tung-Yung; Meng, Pei-Jie; Lu, Chung-Cheng; Lin, Hsing-Juh

    2015-01-01

    Fine sediments, which account for the majority of total fluvial sediment flux, have been suggested to degrade coral reefs on a global scale. Furthermore, sediment impacts can be exacerbated by extreme rainfall events associated with global climate change and anthropogenic nutrient enrichment. We report the findings from a series of mesocosm experiments exploring the effects of short-term sedimentation and nutrient enrichment on the interactions between the hard coral Acropora muricata, the sea anemone Mesactinia ganesis, and the green macroalga Codium edule. Mesocosms were manipulated to simulate either unimpacted reefs or reefs exposed to elevated levels of fine sediments for 10 or 14 days to simulate the effects of heavy rainfall. The first and second experiments were aimed to examine the effects of inorganic and organic sediments, respectively. The third experiment was designed to examine the interactive effects of nutrient enrichment and elevated sediment loads. Neither inorganic nor organic sediment loadings significantly affected the physiological performance of the coral, but, importantly, did reduce its ability to compete with other organisms. Photosynthetic efficiencies of both the green macroalga and the sea anemone increased in response to both sediment loadings when they were simultaneously exposed to nutrient enrichment. While organic sediment loading increased the nitrogen content of the green macroalga in the first experiment, inorganic sediment loading increased its phosphorus content in the second experiment. The coral mortality due to sea anemones attack was significantly greater upon exposure to enriched levels of organic sediments and nutrients. Our findings suggest that the combined effects of short-term sedimentation and nutrient enrichment could cause replacement of corals by sea anemones on certain coral reefs. PMID:25897844

  17. Predator-driven nutrient recycling in California stream ecosystems.

    PubMed

    Munshaw, Robin G; Palen, Wendy J; Courcelles, Danielle M; Finlay, Jacques C

    2013-01-01

    Nutrient recycling by consumers in streams can influence ecosystem nutrient availability and the assemblage and growth of photoautotrophs. Stream fishes can play a large role in nutrient recycling, but contributions by other vertebrates to overall recycling rates remain poorly studied. In tributaries of the Pacific Northwest, coastal giant salamanders (Dicamptodon tenebrosus) occur at high densities alongside steelhead trout (Oncorhynchus mykiss) and are top aquatic predators. We surveyed the density and body size distributions of D. tenebrosus and O. mykiss in a California tributary stream, combined with a field study to determine mass-specific excretion rates of ammonium (N) and total dissolved phosphorus (P) for D. tenebrosus. We estimated O. mykiss excretion rates (N, P) by bioenergetics using field-collected data on the nutrient composition of O. mykiss diets from the same system. Despite lower abundance, D. tenebrosus biomass was 2.5 times higher than O. mykiss. Mass-specific excretion summed over 170 m of stream revealed that O. mykiss recycle 1.7 times more N, and 1.2 times more P than D. tenebrosus, and had a higher N:P ratio (8.7) than that of D. tenebrosus (6.0), or the two species combined (7.5). Through simulated trade-offs in biomass, we estimate that shifts from salamander biomass toward fish biomass have the potential to ease nutrient limitation in forested tributary streams. These results suggest that natural and anthropogenic heterogeneity in the relative abundance of these vertebrates and variation in the uptake rates across river networks can affect broad-scale patterns of nutrient limitation.

  18. Nutrient-dependent/pheromone-controlled adaptive evolution: a model

    PubMed Central

    Kohl, James Vaughn

    2013-01-01

    Background The prenatal migration of gonadotropin-releasing hormone (GnRH) neurosecretory neurons allows nutrients and human pheromones to alter GnRH pulsatility, which modulates the concurrent maturation of the neuroendocrine, reproductive, and central nervous systems, thus influencing the development of ingestive behavior, reproductive sexual behavior, and other behaviors. Methods This model details how chemical ecology drives adaptive evolution via: (1) ecological niche construction, (2) social niche construction, (3) neurogenic niche construction, and (4) socio-cognitive niche construction. This model exemplifies the epigenetic effects of olfactory/pheromonal conditioning, which alters genetically predisposed, nutrient-dependent, hormone-driven mammalian behavior and choices for pheromones that control reproduction via their effects on luteinizing hormone (LH) and systems biology. Results Nutrients are metabolized to pheromones that condition behavior in the same way that food odors condition behavior associated with food preferences. The epigenetic effects of olfactory/pheromonal input calibrate and standardize molecular mechanisms for genetically predisposed receptor-mediated changes in intracellular signaling and stochastic gene expression in GnRH neurosecretory neurons of brain tissue. For example, glucose and pheromones alter the hypothalamic secretion of GnRH and LH. A form of GnRH associated with sexual orientation in yeasts links control of the feedback loops and developmental processes required for nutrient acquisition, movement, reproduction, and the diversification of species from microbes to man. Conclusion An environmental drive evolved from that of nutrient ingestion in unicellular organisms to that of pheromone-controlled socialization in insects. In mammals, food odors and pheromones cause changes in hormones such as LH, which has developmental affects on pheromone-controlled sexual behavior in nutrient-dependent reproductively fit individuals

  19. Effects of nutrient enrichment on mangrove leaf litter decomposition.

    PubMed

    Keuskamp, Joost A; Hefting, Mariet M; Dingemans, Bas J J; Verhoeven, Jos T A; Feller, Ilka C

    2015-03-01

    Nutrient enrichment of mangroves, a common phenomenon along densely populated coastlines, may negatively affect mangrove ecosystems by modifying internal carbon and nutrient cycling. The decomposition of litter exerts a strong influence on these processes and is potentially modified by eutrophication. This study describes effects of N and P enrichment on litter decomposition rate and mineralisation/immobilisation patterns. By making use of reciprocal litter transplantation experiments among fertiliser treatments, it was tested if nutrient addition primarily acts on the primary producers (i.e. changes in litter quantity and quality) or on the microbial decomposers (i.e. changes in nutrient limitation for decomposition). Measurements were done in two mangrove forests where primary production was either limited by N or by P, which had been subject to at least 5 years of experimental N and P fertilisation. Results of this study indicated that decomposers were always N-limited regardless of the limitation of the primary producers. This leads to a differential nutrient limitation between decomposers and primary producers in sites where mangrove production was P-limited. In these sites, fertilisation with P caused litter quality to change, resulting in a higher decomposition rate. This study shows that direct effects of fertilisation on decomposition through an effect on decomposer nutrient availability might be non-significant, while the indirect effects through modifying litter quality might be quite substantial in mangroves. Our results show no indication that eutrophication increases decomposition without stimulating primary production. Therefore we do not expect a decline in carbon sequestration as a result of eutrophication of mangrove ecosystems.

  20. Sexual Function 6 Months After First Delivery

    PubMed Central

    Brubaker, Linda; Handa, Victoria L.; Bradley, Catherine S.; Connolly, AnnaMarie; Moalli, Pamela; Brown, Morton B.; Weber, Anne

    2008-01-01

    OBJECTIVE To explore the association of anal sphincter laceration and sexual function 6 months postpartum in the Childbirth and Pelvic Symptoms (CAPS) cohort. METHODS The primary CAPS study, a prospective cohort study, was designed to estimate the postpartum prevalence and incidence of urinary and fecal incontinence. Three cohorts of new mothers (vaginal delivery with a third- or fourth-degree anal sphincter tear, vaginal delivery without a third- or fourth-degree anal sphincter tear, and cesarean delivery without labor) were compared at 6 months postpartum. Sexual function was assessed with the Pelvic Organ Prolapse/Urinary Incontinence/Sexual Function Short Form Questionnaire (PISQ-12). Urinary and fecal incontinence were assessed using the Medical Epidemiological and Social Aspects of Aging questionnaire and the Fecal Incontinence Severity Index, which is embedded within the Modified Manchester Health Questionnaire. RESULTS Most women (459 [90%]) of those with partners reported sexual activity at the 6-month visit. Fewer women whose delivery was complicated by anal sphincter laceration reported sexual activity when compared with those who delivered vaginally without sphincter laceration (88 compared with 94%, P=.028). The mean PISQ-12 score (39±4) did not differ between delivery groups (P=.92). Pain (responses of “sometimes,” “usually,” or “always”) during sex affected one of three sexually active women (164 [36%]). CONCLUSION At 6 months postpartum, primiparous women who delivered with anal sphincter laceration are less likely to report sexual activity. PMID:18448733

  1. Nanomedicine in pulmonary delivery

    PubMed Central

    Mansour, Heidi M; Rhee, Yun-Seok; Wu, Xiao

    2009-01-01

    The lung is an attractive target for drug delivery due to noninvasive administration via inhalation aerosols, avoidance of first-pass metabolism, direct delivery to the site of action for the treatment of respiratory diseases, and the availability of a huge surface area for local drug action and systemic absorption of drug. Colloidal carriers (ie, nanocarrier systems) in pulmonary drug delivery offer many advantages such as the potential to achieve relatively uniform distribution of drug dose among the alveoli, achievement of improved solubility of the drug from its own aqueous solubility, a sustained drug release which consequently reduces dosing frequency, improves patient compliance, decreases incidence of side effects, and the potential of drug internalization by cells. This review focuses on the current status and explores the potential of colloidal carriers (ie, nanocarrier systems) in pulmonary drug delivery with special attention to their pharmaceutical aspects. Manufacturing processes, in vitro/in vivo evaluation methods, and regulatory/toxicity issues of nanomedicines in pulmonary delivery are also discussed. PMID:20054434

  2. Estuarine circulation-driven entrainment of oceanic nutrients fuels coastal phytoplankton in an open coastal system in Japan

    NASA Astrophysics Data System (ADS)

    Watanabe, Kenta; Kasai, Akihide; Fukuzaki, Koji; Ueno, Masahiro; Yamashita, Yoh

    2017-01-01

    We investigated interactions among seasonal fluctuations in phytoplankton biomass, riverine nutrient flux, and the fluxes of nutrients entrained by estuarine circulation in Tango Bay, Japan, to determine the influence of freshwater inflows to an open bay on coastal phytoplankton productivity. The riverine nutrient flux was strongly regulated by river discharge. Estuarine circulation was driven by river discharge, with high fluxes of nutrients (mean nitrate + nitrite flux: 5.3 ± 3.5 Mg [mega grams]-N day-1) between winter and early spring, enhanced by nutrient supply to the surface water via vertical mixing. In contrast, low-nutrient seawater was delivered to the bay between late spring and summer (1.0 ± 0.8 Mg-N day-1). Seasonal fluctuations in phytoplankton biomass were affected by the entrained fluxes of oceanic nutrients and variation in the euphotic zone depth, and to a lesser degree by the riverine nutrient flux. Bioassays and stoichiometric analyses indicated that phytoplankton growth was limited by nitrogen and/or phosphorus. Both the entrainment of oceanic nutrients and the euphotic zone depth affected the duration and magnitude of blooms. Our findings show that, unlike semi-enclosed bays, seasonal variations in coastal phytoplankton in an open coastal system are primarily fueled by the entrainment of oceanic nutrients and are influenced by both freshwater inflow and coastal conditions (e.g. vertical mixing and wind events).

  3. Food, physiology and drug delivery.

    PubMed

    Varum, F J O; Hatton, G B; Basit, A W

    2013-12-05

    Gastrointestinal physiology is dynamic and complex at the best of times, and a multitude of known variables can affect the overall bioavailability of drugs delivered via the oral route. Yet while the influences of food and beverage intake as just two of these variables on oral drug delivery have been extensively documented in the wider literature, specific information on their effects remains sporadic, and is not so much contextually reviewed. Food co-ingestion with oral dosage forms can mediate several changes to drug bioavailability, yet the precise mechanisms underlying this have yet to be fully elucidated. Likewise, the often detrimental effects of alcohol (ethanol) on dosage form performance have been widely observed experimentally, but knowledge of which has only moderately impacted on clinical practice. Here, we attempt to piece together the available subject matter relating to the influences of both solid and liquid foodstuffs on the gastrointestinal milieu and the implications for oral drug delivery, with particular emphasis on the behaviour of modified-release dosage forms, formulation robustness and drug absorption. Providing better insight into these influences, and exemplifying cases where formulations have been developed or modified to circumvent their associated problems, can help to appropriately direct the design of future in vitro digestive modelling systems as well as oral dosage forms resilient to these effects. Moreover, this will help to better our understanding of the impact of food and alcohol intake on normal gut behaviour and function.

  4. Maternal contributions to preterm delivery.

    PubMed

    Boyd, Heather A; Poulsen, Gry; Wohlfahrt, Jan; Murray, Jeffrey C; Feenstra, Bjarke; Melbye, Mads

    2009-12-01

    Preterm delivery (PTD) is a complex trait with a significant familial component. However, no specific inheritance patterns have been established. The authors examined the contribution of PTDs in both the woman's family and her partner's family to her risk of PTD. The authors linked birth information from Danish national registers with pedigree information from the Danish Family Relations Database for 1,107,124 live singleton deliveries occurring from 1978 to 2004. Risk ratios were estimated comparing women with and without various PTD histories. Women with previous PTDs were at greatly increased risk of recurrent PTD (risk ratio = 5.6, 95% confidence interval: 5.5, 5.8); however, their PTD risk was unaffected by a partner's history of preterm children with other women. PTDs to a woman's mother, full sisters, or maternal half-sisters also increased her PTD risk (risk ratio = 1.6, 95% confidence interval: 1.5, 1.6), whereas PTDs in her paternal half-sisters, the female partners of her male relatives, or members of her partner's family did not affect her PTD risk. Inheritance patterns were similar for all gestational ages from very early through late PTD. The substantial portion of PTD risk explained by effects passed through the female line suggests a role for either imprinting or mitochondrial inheritance.

  5. Nutrient Management in Recirculating Hydroponic Culture

    NASA Technical Reports Server (NTRS)

    Bugbee, Bruce

    2004-01-01

    There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

  6. Flux balancing of light and nutrients in a biofilm photobioreactor for maximizing photosynthetic productivity.

    PubMed

    Murphy, Thomas E; Berberoglu, Halil

    2014-01-01

    This article reports a combined experimental and numerical study on the efficient operation of Porous Substrate Bioreactors. A comprehensive model integrating light transport, mass transport, and algal growth kinetics was used to understand the productivity of photosynthetic biofilms in response to delivery rates of photons and nutrients. The reactor under consideration was an evaporation driven Porous Substrate Bioreactor (PSBR) cultivating the cyanobacteria Anabaena variabilis as a biofilm on a porous substrate which delivers water and nutrients to the cells. In an unoptimized experimental case, this reactor was operated with a photosynthetic efficiency of 2.3%, competitive with conventional photobioreactors. Moreover, through a scaling analysis, the location at which the phosphate delivery rate decreased the growth rate to half of its uninhibited value was predicted as a function of microorganism and bioreactor properties. The numerical model along with the flux balancing techniques presented herein can serve as tools for designing and selecting operating parameters of biofilm based cultivation systems for maximum productivity.

  7. Cool tadpoles from Arctic environments waste fewer nutrients - high gross growth efficiencies lead to low consumer-mediated nutrient recycling in the North.

    PubMed

    Liess, Antonia; Guo, Junwen; Lind, Martin I; Rowe, Owen

    2015-11-01

    Endothermic organisms can adapt to short growing seasons, low temperatures and nutrient limitation by developing high growth rates and high gross growth efficiencies (GGEs). Animals with high GGEs are better at assimilating limiting nutrients and thus should recycle (or lose) fewer nutrients. Longer guts in relation to body mass may facilitate higher GGE under resource limitation. Within the context of ecological stoichiometry theory, this study combines ecology with evolution by relating latitudinal life-history adaptations in GGE, mediated by gut length, to its ecosystem consequences, such as consumer-mediated nutrient recycling. In common garden experiments, we raised Rana temporaria tadpoles from two regions (Arctic/Boreal) under two temperature regimes (18/23 °C) crossed with two food quality treatments (high/low-nitrogen content). We measured tadpole GGEs, total nutrient loss (excretion + egestion) rates and gut length during ontogeny. In order to maintain their elemental balance, tadpoles fed low-nitrogen (N) food had lower N excretion rates and higher total phosphorous (P) loss rates than tadpoles fed high-quality food. In accordance with expectations, Arctic tadpoles had higher GGEs and lower N loss rates than their low-latitude conspecifics, especially when fed low-N food, but only in ambient temperature treatments. Arctic tadpoles also had relatively longer guts than Boreal tadpoles during early development. That temperature and food quality interacted with tadpole region of origin in affecting tadpole GGEs, nutrient loss rates and relative gut length, suggests evolved adaptation to temperature and resource differences. With future climate change, mean annual temperatures will increase. Additionally, species and genotypes will migrate north. This will change the functioning of Boreal and Arctic ecosystems by affecting consumer-mediated nutrient recycling and thus affect nutrient dynamics in general. Our study shows that evolved latitudinal adaption can

  8. The effect of pH on phosphorus availability and speciation in an aquaponics nutrient solution.

    PubMed

    Cerozi, Brunno da Silva; Fitzsimmons, Kevin

    2016-11-01

    The interaction between the main ions in aquaponics nutrient solutions affects chemical composition and availability of nutrients, and nutrient uptake by plant roots. This study determined the effect of pH on phosphorus (P) speciation and availability in an aquaponics nutrient solution and used Visual MINTEQ to simulate P species and P activity. In both experimental and simulated results, P availability decreased with increase in pH of aquaponics nutrient solutions. According to simulations, P binds to several cations leaving less free phosphate ions available in solution. High pH values resulted in the formation of insoluble calcium phosphate species. The study also demonstrated the importance of organic matter and alkalinity in keeping free phosphate ions in solution at high pH ranges. It is recommended though that pH in aquaponics systems is maintained at a 5.5-7.2 range for optimal availability and uptake by plants.

  9. Nutrient inputs to the Laurentian Great Lakes by source and watershed estimated using SPARROW watershed models

    USGS Publications Warehouse

    Robertson, Dale M.; Saad, David A.

    2011-01-01

    Nutrient input to the Laurentian Great Lakes continues to cause problems with eutrophication. To reduce the extent and severity of these problems, target nutrient loads were established and Total Maximum Daily Loads are being developed for many tributaries. Without detailed loading information it is difficult to determine if the targets are being met and how to prioritize rehabilitation efforts. To help address these issues, SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed for estimating loads and sources of phosphorus (P) and nitrogen (N) from the United States (U.S.) portion of the Great Lakes, Upper Mississippi, Ohio, and Red River Basins. Results indicated that recent U.S. loadings to Lakes Michigan and Ontario are similar to those in the 1980s, whereas loadings to Lakes Superior, Huron, and Erie decreased. Highest loads were from tributaries with the largest watersheds, whereas highest yields were from areas with intense agriculture and large point sources of nutrients. Tributaries were ranked based on their relative loads and yields to each lake. Input from agricultural areas was a significant source of nutrients, contributing ∼33-44% of the P and ∼33-58% of the N, except for areas around Superior with little agriculture. Point sources were also significant, contributing ∼14-44% of the P and 13-34% of the N. Watersheds around Lake Erie contributed nutrients at the highest rate (similar to intensively farmed areas in the Midwest) because they have the largest nutrient inputs and highest delivery ratio.

  10. A mathematical model of water and nutrient transport in xylem vessels of a wheat plant.

    PubMed

    Payvandi, S; Daly, K R; Jones, D L; Talboys, P; Zygalakis, K C; Roose, T

    2014-03-01

    At a time of increasing global demand for food, dwindling land and resources, and escalating pressures from climate change, the farming industry is undergoing financial strain, with a need to improve efficiency and crop yields. In order to improve efficiencies in farming, and in fertiliser usage in particular, understanding must be gained of the fertiliser-to-crop-yield pathway. We model one aspect of this pathway; the transport of nutrients within the vascular tissues of a crop plant from roots to leaves. We present a mathematical model of the transport of nutrients within the xylem vessels in response to the evapotranspiration of water. We determine seven different classes of flow, including positive unidirectional flow, which is optimal for nutrient transport from the roots to the leaves; and root multidirectional flow, which is similar to the hydraulic lift process observed in plants. We also investigate the effect of diffusion on nutrient transport and find that diffusion can be significant at the vessel termini especially if there is an axial efflux of nutrient, and at night when transpiration is minimal. Models such as these can then be coupled to whole-plant models to be used for optimisation of nutrient delivery scenarios.

  11. Transcutaneous antigen delivery system

    PubMed Central

    Lee, Mi-Young; Shin, Meong-Cheol; Yang, Victor C.

    2013-01-01

    Transcutaneous immunization refers to the topical application of antigens onto the epidermis. Transcutaneous immunization targeting the Langerhans cells of the skin has received much attention due to its safe, needle-free, and noninvasive antigen delivery. The skin has important immunological functions with unique roles for antigen-presenting cells such as epidermal Langerhans cells and dermal dendritic cells. In recent years, novel vaccine delivery strategies have continually been developed; however, transcutaneous immunization has not yet been fully exploited due to the penetration barrier represented by the stratum corneum, which inhibits the transport of antigens and adjuvants. Herein we review recent achievements in transcutaneous immunization, focusing on the various strategies for the enhancement of antigen delivery and vaccination efficacy. [BMB Reports 2013; 46(1): 17-24] PMID:23351379

  12. Metrology for drug delivery.

    PubMed

    Lucas, Peter; Klein, Stephan

    2015-08-01

    In various recently published studies, it is argued that there are underestimated risks with infusion technology, i.e., adverse incidents believed to be caused by inadequate administration of the drugs. This is particularly the case for applications involving very low-flow rates, i.e., <1 ml/h and applications involving drug delivery by means of multiple pumps. The risks in infusing are caused by a lack of awareness, incompletely understood properties of the complete drug delivery system and a lack of a proper metrological infrastructure for low-flow rates. Technical challenges such as these were the reason a European research project "Metrology for Drug Delivery" was started in 2011. In this special issue of Biomedical Engineering, the results of that project are discussed.

  13. Biopolymers as transdermal drug delivery systems in dermatology therapy.

    PubMed

    Basavaraj, K H; Johnsy, George; Navya, M A; Rashmi, R; Siddaramaiah

    2010-01-01

    The skin is considered a complex organ for drug delivery because of its structure. Drug delivery systems are designed for the controlled release of drugs through the skin into the systemic circulation, maintaining consistent efficacy and reducing the dose of the drugs and their related side effects. Transdermal drug delivery represents one of the most rapidly advancing areas of novel drug delivery. The excellent impervious nature of the skin is the greatest challenge that must be overcome for successful drug delivery. Today, polymers have been proven to be successful for long-term drug delivery applications as no single polymer can satisfy all of the requirements. Biopolymers in the field of dermal application are rare and the mechanisms that affect skin absorption are almost unknown. Biopolymers are widely used as drug delivery systems, but as such the use of biopolymers as drug delivery systems in dermatologic therapy is still in progress. Commonly used biopolymers include hydrocolloids, alginates, hydrogels, polyurethane, collagen, poly(lactic-co-glycolic acid), chitosan, proteins and peptides, pectin, siRNAs, and hyaluronic acid. These new and exciting methods for drug delivery are already increasing the number and quality of dermal and transdermal therapies. This article reviews current research on biopolymers and focuses on their potential as drug carriers, particularly in relation to the dermatologic aspects of their use.

  14. Nutrients, satiety, and control of energy intake.

    PubMed

    Tremblay, Angelo; Bellisle, France

    2015-10-01

    In the context of the worldwide epidemic of obesity affecting men and women of all ages, it is important to understand the mechanisms that control human appetite, particularly those that allow the adjustment of energy intake to energy needs. Satiety is one important psycho-biological mechanism whose function is to inhibit intake following the ingestion of a food or a beverage. According to the classical theories of appetite control, satiety is influenced by macronutrient intake and/or metabolism. Satiety also seems to be modified by micronutrients, non-nutrients, and some bioactive food constituents. Under optimal conditions, satiety should be well connected with hunger and satiation in a way that spontaneously leads to a close match between energy intake and expenditures. However, the current obesity epidemic suggests that dysfunctions often affect satiety and energy intake. In this regard, this paper presents a conceptual integration that hopefully will help health professionals address satiety issues and provide the public with informed advice to facilitate appetite control.

  15. Sublingual drug delivery.

    PubMed

    Goswami, Tarun; Jasti, Bhaskara; Li, Xiaoling

    2008-01-01

    The sublingual route is one of the early modes of administration for systemic drug delivery. This route avoids first-pass metabolism and affords quick drug entry into the systemic circulation. Attempts have been made to deliver various pharmacologically active agents, such as cardiovascular drugs, analgesics, and peptides, across the sublingual mucosa. In this review, the anatomical structure, blood supply, biochemical composition, transport pathways, permeation enhancement strategies, in vitro/in vivo models, and clinical investigations for the sublingual route of drug delivery is discussed.

  16. [Response of fine roots to soil nutrient spatial heterogeneity].

    PubMed

    Wang, Qingcheng; Cheng, Yunhuan

    2004-06-01

    The spatial heterogeneity is the complexity and variation of systems or their attributes, and the heterogeneity of soil nutrients is ubiquitous in all natural ecosystems. The scale of spatial heterogeneity varies considerably among different ecosystems, from tens of centimeters to hundred meters. Some of the scales can be detected by individual plant. Because the growth of individual plants can be strongly influenced by soil heterogeneity, it follows that the inter-specific competition should also be affected. During the long process of evolution, plants developed various plastic responses with their root system, including morphological, physiological and mycorrhizal plasticity, to maximize the nutrient acquisition from heterogeneous soil resources. Morphological plasticity, an adjustment in root system spatial allocation and architecture in response to spatial heterogeneous distribution of available soil resources, has been most intensively studied, and root proliferation in nutrient rich patches has been certified for many species. The species that do respond may have an increased rate of nutrient uptake, leading to a competitive advantage. Scale and precision are two important features employed in describing the size and foraging behavior of root system. It was hypothesized that scale and precision is negatively related, i. e., the species with high scale of root system tend to be a less precise forager. The outcomes of different research work have been diverse, far from reaching a consensus. Species with high scale are not necessarily less precise in fine root allocation, and vice versa. The proliferation of fine root in enriched micro-sites is species dependent, and also affected by other factors, such as patch attributes (size and nutrients concentration), nutrients, and overall soil fertility. Beside root proliferation in nutrient enriched patches, plants can also adapt themselves to the heterogeneous soil environment by altering other root characteristics

  17. Top-down and bottom-up control of stream periphyton: Effects of nutrients and herbivores

    SciTech Connect

    Rosemond, A.D. ); Mulholland, P.J.; Elwood, J.W. )

    1993-06-01

    Two experiments determineD the relative effects of herbivory and nutrients on an algal community in in a stream having effectively two trophic levels: primary producers and herbivorous snails. The first study (1989), in streamside channels, tested the effects of three factors: (1) stream water nitrogen (N), (2) phosphorus (P), and (3) snail grazing, on periphyton biomass, productivity, and community composition. The second study (1990), conducted in situ, tested the effects of snail grazing and nutrients (N + P). In the 1989 study, nutrients had positive effects, and herbivores had negative effects, on algal biomass and primary productivity. Likewise, both nutrients and snail grazing exerted effects (+ and [minus], respectively) on biomass measured in the 1990 study. Grazed communities, dominated by chlorophytes and cyanophytes, were overgrown by diatoms when herbivores were removed. Algal species , reduced the most by herbivores, were increased most by nutrient addition, and vice versa, suggesting a trade-off between resistance to herbivory and nutrient-saturated growth rates. The greatest changes in periphyton structure or function were observed when both N and P were added and simultaneously, grazers were removed, in contrast to lesser effects when nutrients were added under grazed conditions or grazers were removed at low nutrient levels, indicating dual control by both factors. Nutrient addition also positively affected snail growth in both experiments, indicating tight coupling between herbivore and algal growth (top-down effects) and that bottom-up factors that directly affected plant growth could also indirectly affect consumers belonging to higher trophic levels. Indices showed that the relative strength of top-down and bottom-up factors varied among biomass and productivity parameters and that top-down and bottom-up effects, alone, were less important than their combined effects. 67 refs., 8 figs., 7 tabs.

  18. Examination of relation between nutrient components and fruits: biplot approach.

    PubMed

    Atakan, Cemal; Alkan, Baris; Sahin, Afsin

    2009-01-01

    Adequate intake of fruits and vegetables as part of the daily diet may help prevent major diseases. Low fruit intake is a major risk factor for cancer, coronary heart disease and stroke. The World Health Organization recommends eating at least five portions of a variety of fruit, which is nearly 400 g/day. Essential nutrients, water, carbohydrates, oils and vitamins are needed in appropriate quantities in order to have a well-functioning body. In this study we try to carry out a food composition study to identify and determine the chemical nature of the organic and inorganic macro-nutrient and micro-nutrient properties of the main fruit types that affect human nature, by a biplot graphical approach. The biplot can be considered as multivariate equivalents of scatter plots that have been used for graphically analyzing bivariate data. Biplot approaches show a simultaneous display of fruits and nutrient components in low dimensions. In the present study, the theory of biplot and different types of biplot will be given and than an application of the biplot approach will be applied to the real data.

  19. Herbivores and nutrients control grassland plant diversity via light limitation.

    SciTech Connect

    Borer, Elizabeth T.; et al, et al

    2014-01-01

    Human alterations to nutrient cycles1,2 and herbivore communities3–7 are affecting global biodiversity dramatically2. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems8,9. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

  20. Modelling and simulation of nutrient dispersion from coated fertilizer granules

    NASA Astrophysics Data System (ADS)

    Razali, Radzuan; Daud, Hanita; Nor, Shafiq Mohd.

    2014-10-01

    The usage of Controlled-Release Fertilizer (CRF) is essential in plants and crops to fulfill the need and requirement for the modern agriculture which now feeds 6 billion people. Therefore modeling and simulation of nutrient release from coated fertilizer has become the best method to study the behavior of some parameters toward water saturation in and nutrient release from the coated-fertilizer granule. This paper is the improvement development of modeling and computer simulation by Basu [1] which include some of the factors affecting the water saturation time and nutrient release time from a coated-fertilizer. The effect of granule radius, the diffusivity of water and nutrient, the temperature of surrounding, the contact areas and the characteristic of the coating are studied and the simulation was developed using MATLAB software. The studies and understanding of this project is very important and useful especially to determine the important parameters in the manufacturing process of the coated-fertilizer granule and also will be useful for the farmers/users in the selection of the best fertilizers for their crops.

  1. Nutrient levels modify saltmarsh responses to increased inundation in different soil types.

    PubMed

    Wong, Joanne X W; Van Colen, Carl; Airoldi, Laura

    2015-03-01

    Saltmarshes have been depleted historically, and cumulative stressors threaten their future persistence. We examined experimentally how nutrient availability (high vs. low) affects the responses of Spartina maritima to increased inundation in two mineral soil types (low vs. medium organic). Increased inundation, one of the effects of accelerated sea level rise, had negative effects on most plant growth parameters, but the magnitude varied with soil and nutrient levels, and between plants from different locations. Average differences between inundation treatments were largest at high nutrient conditions in low organic matter soils. We conclude that saltmarsh vegetation would be more drastically affected by increased inundation in low than in medium organic matter soils, and especially in estuaries already under high nutrient availability. This knowledge enhances the prediction of changes at the foreshore of saltmarshes related to sea level rise, and the development of site-specific conservation strategies.

  2. Plant and pathogen nutrient acquisition strategies

    PubMed Central

    Fatima, Urooj; Senthil-Kumar, Muthappa

    2015-01-01

    Nutrients are indispensable elements required for the growth of all living organisms including plants and pathogens. Phyllosphere, rhizosphere, apoplast, phloem, xylem, and cell organelles are the nutrient niches in plants that are the target of bacterial pathogens. Depending upon nutrients availability, the pathogen adapts various acquisition strategies and inhabits the specific niche. In this review, we discuss the nutrient composition of different niches in plants, the mechanisms involved in the recognition of nutrient niche and the sophisticated strategies used by the bacterial pathogens for acquiring nutrients. We provide insight into various nutrient acquisition strategies used by necrotrophic, biotrophic, and hemibiotrophic bacteria. Specifically we discuss both modulation of bacterial machinery and manipulation of host machinery. In addition, we highlight the current status of our understanding about the nutrient acquisition strategies used by bacterial pathogens, namely targeting the sugar transporters that are dedicated for the plant’s growth and development. Bacterial strategies for altering the plant cell membrane permeability to enhance the release of nutrients are also enumerated along with in-depth analysis of molecular mechanisms behind these strategies. The information presented in this review will be useful to understand the plant–pathogen interaction in nutrient perspective. PMID:26442063

  3. Systems and Components Fuel Delivery System, Water Delivery System, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Systems and Components - Fuel Delivery System, Water Delivery System, Derrick Crane System, and Crane System Details - Marshall Space Flight Center, F-1 Engine Static Test Stand, On Route 565 between Huntsville and Decatur, Huntsville, Madison County, AL

  4. Novel starch based nano scale enteric coatings from soybean meal for colon-specific delivery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean meal was used to isolate resistant starch and produce nanoparticles, which could be potential coating materials for colonic nutrient and drug deliveries. The nanoparticles were in 40 +/- 33.2 nm ranges. These nanoparticles were stable under simulated human physiological conditions. The deg...

  5. Caesarean Delivery Rate Review: An Evidence-Based Analysis

    PubMed Central

    Degani, N; Sikich, N

    2015-01-01

    Background In 2007, caesarean deliveries comprised 28% of all hospital deliveries in Ontario. Provincial caesarean delivery rates increased with maternal age and varied by Local Health Integration Network. However, the accepted rate of caesarean delivery in a low-risk maternal population remains unclear. Objectives To review the literature to assess factors that affect the likelihood of experiencing a caesarean delivery, and to examine Ontario caesarean delivery rates to determine whether there is rate variation across the province. Data Sources Data sources included publications from OVID MEDLINE, OVID MEDLINE In-Process and Other Non-Indexed Citations, OVID Embase, EBSCO Cumulative Index to Nursing & Allied Health Literature (CINAHL), and EBM Reviews, as well as data from the Canadian Institute for Health Information Discharge Abstracts Database and the Better Outcomes and Registry Network. Review Methods A mixed-methods approach was used, which included a systematic review of the literature to delineate factors associated with the likelihood of caesarean delivery and an analysis of administrative and clinical data on hospital deliveries in Ontario to determine provincial caesarean delivery rates, variation in rates, and reasons for variation. Results Fourteen systematic reviews assessed 14 factors affecting the likelihood of caesarean delivery; 7 factors were associated with an increased likelihood of caesarean delivery, and 2 factors were associated with a decreased likelihood. Five factors had no influence. One factor provided moderate-quality evidence supporting elective induction policies in low-risk women. The overall Ontario caesarean delivery rate in a very-low-risk population was 17%, but varied significantly across Ontario hospitals. Limitations The literature review included a 5–year period and used only systematic reviews. The determination of Robson class for women is based on care received in hospital only, and the low-risk population may have

  6. Upward cascading effects of nutrients: shifts in a benthic microalgal community and a negative herbivore response.

    PubMed

    Armitage, Anna R; Fong, Peggy

    2004-05-01

    We evaluated the effects of nutrient addition on interactions between the benthic microalgal community and a dominant herbivorous gastropod, Cerithidea californica (California horn snail), on tidal flats in Mugu Lagoon, southern California, USA. We crossed snail and nutrient (N and P) addition treatments in enclosures on two tidal flats varying from 71 to 92% sand content in a temporally replicated experiment (summer 2000, fall 2000, spring 2001). Diatom biomass increased slightly (approximately 30%) in response to nutrient treatments but was not affected by snails. Blooms of cyanobacteria (up to 200%) and purple sulfur bacteria (up to 400%) occurred in response to nutrient enrichment, particularly in the sandier site, but only cyanobacterial biomass decreased in response to snail grazing. Snail mortality was 2-5 times higher in response to nutrient addition, especially in the sandier site, corresponding to a relative increase in cyanobacterial biomass. Nutrient-related snail mortality occurred only in the spring and summer, when the snails were most actively feeding on the microalgal community. Inactive snails in the fall showed no response to nutrient-induced cyanobacterial growths. This study demonstrated strongly negative upward cascading effects of nutrient enrichment through the food chain. The strength of this upward cascade was closely linked to sediment type and microalgal community composition.

  7. Uncovering miRNAs involved in crosstalk between nutrient deficiencies in Arabidopsis.

    PubMed

    Liang, Gang; Ai, Qin; Yu, Diqiu

    2015-07-02

    Integrating carbon (C), nitrogen (N), and sulfur (S) metabolism is essential for the growth and development of living organisms. MicroRNAs (miRNAs) play key roles in regulating nutrient metabolism in plants. However, how plant miRNAs mediate crosstalk between different nutrient metabolic pathways is unclear. In this study, deep sequencing of Arabidopsis thaliana small RNAs was used to reveal miRNAs that were differentially expressed in response to C, N, or S deficiency. Comparative analysis revealed that the targets of the differentially expressed miRNAs are involved in different cellular responses and metabolic processes, including transcriptional regulation, auxin signal transduction, nutrient homeostasis, and regulation of development. C, N, and S deficiency specifically induced miR169b/c, miR826 and miR395, respectively. In contrast, miR167, miR172, miR397, miR398, miR399, miR408, miR775, miR827, miR841, miR857, and miR2111 are commonly suppressed by C, N, and S deficiency. In particular, the miRNAs that are induced specifically by a certain nutrient deficiency are often suppressed by other nutrient deficiencies. Further investigation indicated that the modulation of nutrient-responsive miRNA abundance affects the adaptation of plants to nutrient starvation conditions. This study revealed that miRNAs function as important regulatory nodes of different nutrient metabolic pathways.

  8. Root growth and plant biomass in Lolium perenne exploring a nutrient-rich patch in soil.

    PubMed

    Nakamura, Ryoji; Kachi, Naoki; Suzuki, Jun-Ichirou

    2008-11-01

    We investigated soil exploration by roots and plant growth in a heterogeneous environment to determine whether roots can selectively explore a nutrient-rich patch, and how nutrient heterogeneity affects biomass allocation and total biomass before a patch is reached. Lolium perenne L. plants were grown in a factorial experiment with combinations of fertilization (heterogeneous and homogeneous) and day of harvest (14, 28, 42, or 56 days after transplanting). The plant in the heterogeneous treatment was smaller in its mean total biomass, and allocated more biomass to roots. The distributions of root length and root biomass in the heterogeneous treatment did not favor the nutrient-rich patch, and did not correspond to the patchy distribution of inorganic nitrogen. Specific root length (length/biomass) was higher and root elongation was more extensive both laterally and vertically in the heterogeneous treatment. These characteristics may enable plants to acquire nutrients efficiently and increase the probability of encountering nutrient-rich patches in a heterogeneous soil. However, heterogeneity of soil nutrients would hold back plant growth before a patch was reached. Therefore, although no significant selective root placement in the nutrient-rich patch was observed, plant growth before reaching nutrient-rich patches differed between heterogeneous and homogeneous environments.

  9. Evolution of root plasticity responses to variation in soil nutrient distribution and concentration.

    PubMed

    Grossman, Judah D; Rice, Kevin J

    2012-12-01

    Root plasticity, a trait that can respond to selective pressure, may help plants forage for nutrients in heterogeneous soils. Agricultural breeding programs have artificially selected for increased yield under comparatively homogeneous soil conditions, potentially decreasing the capacity for plasticity in crop plants like barley (Hordeum vulgare). However, the effects of domestication on the evolution of root plasticity are essentially unknown. Using a split container approach, we examined the differences in root plasticity among three domestication levels of barley germplasm (wild, landrace, and cultivar) grown under different concentrations and distribution patterns of soil nutrients. Domestication level, nutrient concentration, and nutrient distribution interactively affected average root diameter; differential root allocation (within-plant plasticity) was greatest in wild barley (Hordeum spontaneum), especially under low nutrient levels. Correlations of within-plant root plasticity and plant size were most pronounced in modern cultivars under low-nutrient conditions. Barley plants invested more resources to root systems when grown in low-nutrient soils and allocated more roots to higher-nutrient locations. Root plasticity in barley is scale dependent and varies with domestication level. Although wild barley harbors a greater capacity for within-plant root plasticity than domesticated barley, cultivars exhibited the greatest capacity to translate within-plant plasticity into increased plant size.

  10. Animal pee in the sea: consumer-mediated nutrient dynamics in the world's changing oceans.

    PubMed

    Allgeier, Jacob E; Burkepile, Deron E; Layman, Craig A

    2017-02-20

    Humans have drastically altered the abundance of animals in marine ecosystems via exploitation. Reduced abundance can destabilize food webs, leading to cascading indirect effects that dramatically reorganize community structure and shift ecosystem function. However, the additional implications of these top-down changes for biogeochemical cycles via consumer-mediated nutrient dynamics (CND) are often overlooked in marine systems, particularly in coastal areas. Here, we review research that underscores the importance of this bottom-up control at local, regional, and global scales in coastal marine ecosystems, and the potential implications of anthropogenic change to fundamentally alter these processes. We focus attention on the two primary ways consumers affect nutrient dynamics, with emphasis on implications for the nutrient capacity of ecosystems: (1) the storage and retention of nutrients in biomass, and (2) the supply of nutrients via excretion and egestion. Nutrient storage in consumer biomass may be especially important in many marine ecosystems because consumers, as opposed to producers, often dominate organismal biomass. As for nutrient supply, we emphasize how consumers enhance primary production through both press and pulse dynamics. Looking forward, we explore the importance of CDN for improving theory (e.g., ecological stoichiometry, metabolic theory, and biodiversity-ecosystem function relationships), all in the context of global environmental change. Increasing research focus on CND will likely transform our perspectives on how consumers affect the functioning of marine ecosystems.

  11. Culturing Selenastrum capricornutum (Chlorophyta) in a synthetic algal nutrient medium with defined mineral particulates

    USGS Publications Warehouse

    Kuwabara, J.S.; Davis, J.A.; Chang, Cecily C.Y.

    1985-01-01

    Algal nutrient studies in chemically-defined media typically employ a synthetic chelator to prevent iron hydroxide precipitation. Micronutrient-particulate interactions may, however, significantly affect chemical speciation and hence biovailability of these nutrients in natural waters. A technique is described by which Selenastrum capricornutum Printz (Chlorophyta) may be cultured in a medium where trace metal speciation (except iron) is controlled, not by organic chelation, but by sorption onto titanium dioxide. Application of this culturing protocol in conjunction with results from sorption studies of nutrient ions on mineral particles provides a means of studying biological impacts of sorptive processes in aquatic environments. ?? 1985 Dr W. Junk Publishers.

  12. Interactions Among Water, Carbon, And Nutrient Cycles With Woody Plant Encroachment Into Grasslands

    NASA Astrophysics Data System (ADS)

    Jackson, R. B.; Engel, V.; Jobbagy, E. G.; McElrone, A. J.; Pockman, W. T.

    2003-12-01

    The expansion of woody plants into deserts, grasslands, and savannas alters water and nutrient cycling, affecting some one-fifth of the world's population. In this talk, research along precipitation gradients in North and South America will be used to examine interactions among water, carbon and nutrients in the southwestern U.S. and in grasslands of Argentina and Uruguay. Those interactions include groundwater uptake, carbon sequestration, changes in salinity and pH, and new evidence for the direct uptake of nutrients at depth using stable isotopes. The talk will end with a discussion of key unanswered research questions at the boundary of hydrology, biology, and geochemistry associated with woody plant encroachment.

  13. Document Delivery Update.

    ERIC Educational Resources Information Center

    Nelson, Nancy Melin

    1992-01-01

    Presents highlights of research that used industrywide surveys, focus groups, personal interviews, and industry-published data to explore the future of electronic information delivery in libraries. Topics discussed include CD-ROMs; prices; full-text products; magnetic tape leasing; engineering and technical literature; connections between online…

  14. Fluid delivery control system

    SciTech Connect

    Hoff, Brian D.; Johnson, Kris William; Algrain, Marcelo C.; Akasam, Sivaprasad

    2006-06-06

    A method of controlling the delivery of fluid to an engine includes receiving a fuel flow rate signal. An electric pump is arranged to deliver fluid to the engine. The speed of the electric pump is controlled based on the fuel flow rate signal.

  15. Educational Telecommunications Delivery Systems.

    ERIC Educational Resources Information Center

    Curtis, John A., Ed.; Biedenbach, Joseph M., Ed.

    This monograph is a single volume reference manual providing an overall review of the current status and likely near future application of six major educational telecommunications delivery technologies. The introduction provides an overview to the usage and potential for these systems in the context of the major educational issues involved. Each…

  16. Choosing Training Delivery Media.

    ERIC Educational Resources Information Center

    Hybert, Peter R.

    2000-01-01

    Focuses on decisionmaking about delivery media, and introduces CADDI's Performance-based, Accelerated, Customer-Stakeholder-driven Training & Development(SM) (PACT) Processes for training and development (T&D). Describes the media decisions that correspond with the design three levels of PACT: Curriculum Architecture Design, Modular Curriculum…

  17. Linking nutrient loading and oxygen in the coastal ocean: A new global scale model

    NASA Astrophysics Data System (ADS)

    Reed, Daniel C.; Harrison, John A.

    2016-03-01

    Recent decades have witnessed an exponential spread of low-oxygen regions in the coastal ocean due at least in-part to enhanced terrestrial nutrient inputs. As oxygen deprivation is a major stressor on marine ecosystems, there is a great need to quantitatively link shifts in nutrient loading with changes in oxygen concentrations. To this end, we have developed and here describe, evaluate, and apply the Coastal Ocean Oxygen Linked to Benthic Exchange And Nutrient Supply (COOLBEANS) model, a first-of-its-kind, spatially explicit (with 152 coastal segments) model, global model of coastal oxygen and nutrient dynamics. In COOLBEANS, benthic oxygen demand (BOD) is calculated using empirical models for aerobic respiration, iron reduction, and sulfate reduction, while oxygen supply is represented by a simple parameterization of exchange between surface and bottom waters. A nutrient cycling component translates shifts in riverine nutrient inputs into changes in organic matter delivery to sediments and, ultimately, oxygen uptake. Modeled BOD reproduces observations reasonably well (Nash-Sutcliffe efficiency = 0.71), and estimates of exchange between surface and bottom waters correlate with stratification. The model examines sensitivity of bottom water oxygen to changes in nutrient inputs and vertical exchange between surface and bottom waters, highlighting the importance of this vertical exchange in defining the susceptibility of a system to oxygen depletion. These sensitivities along with estimated maximum hypoxic areas that are supported by present day nutrient loads are consistent with existing hypoxic regions. Sensitivities are put into context by applying historic changes in nitrogen loading observed in the Gulf of Mexico to the global coastal ocean, demonstrating that such loads would drive many systems anoxic or even sulfidic.

  18. Effect of Surface Properties on Liposomal siRNA Delivery

    PubMed Central

    Xia, Yuqiong; Tian, Jie; Chen, Xiaoyuan

    2015-01-01

    Liposomes are one of the most widely investigated carriers for siRNA delivery. The surface properties of liposomal carriers, including the surface charge, PEGylation, and ligand modification can significantly affect the gene silencing efficiency. Three barriers of systemic siRNA delivery (long blood circulation, efficient tumor penetration and efficient cellular uptake/endosomal escape) are analyzed on liposomal carriers with different surface charges, PEGylations and ligand modifications. Cationic formulations dominate siRNA delivery and neutral formulations also have good performance while anionic formulations are generally not proper for siRNA delivery. The PEG dilemma (prolonged blood circulation vs. reduced cellular uptake/endosomal escape) and the side effect of repeated PEGylated formulation (accelerated blood clearance) were discussed. Effects of ligand modification on cationic and neutral formulations were analyzed. Finally, we summarized the achievements in liposomal siRNA delivery, outlined existing problems and provided some future perspectives. PMID:26695117

  19. Interfacing carbon nanotubes (CNT) with plants: enhancement of growth, water and ionic nutrient uptake in maize ( Zea mays) and implications for nanoagriculture

    NASA Astrophysics Data System (ADS)

    Tiwari, D. K.; Dasgupta-Schubert, N.; Villaseñor Cendejas, L. M.; Villegas, J.; Carreto Montoya, L.; Borjas García, S. E.

    2014-06-01

    The application of nano-biotechnology to crop-science/agriculture (`nanoagriculture') is a recent development. While carbon nanotubes (CNTs) have been shown to dramatically improve germination of some comestible plants, deficiencies in consistency of behavior and reproducibility arise, partially from the variability of the CNTs used. In this work, factory-synthesized multi-walled-CNTs (MWCNTs) of quality-controlled specifications were seen to enhance the germinative growth of maize seedlings at low concentrations but depress it at higher concentrations. Growth enhancement principally arose through improved water delivery by the MWCNT. Polarized EDXRF spectrometry showed that MWCNTs affect mineral nutrient supply to the seedling through the action of the mutually opposing forces of inflow with water and retention in the medium by the ion-CNT transient-dipole interaction. The effect varied with ion type and MWCNT concentration. The differences of the Fe tissue concentrations when relatively high equimolar Fe2+ or Fe3+ was introduced, implied that the ion-CNT interaction might induce redox changes to the ion. The tissue Ca2+ concentration manifested as the antipode of the Fe2+ concentration indicating a possible cationic exchange in the cell wall matrix. SEM images showed that MWCNTs perforated the black-layer seed-coat that could explain the enhanced water delivery. The absence of perforations with the introduction of FeCl2/FeCl3 reinforces the idea of the modification of MWCNT functionality by the ion-CNT interaction. Overall, in normal media, low dose MWCNTs were seen to be beneficial, improving water absorption, plant biomass and the concentrations of the essential Ca, Fe nutrients, opening a potential for possible future commercial agricultural applications.

  20. [Research advances on controlled-release mechanisms of nutrients in coated fertilizers].

    PubMed

    Zhang, Haijun; Wu, Zhijie; Liang, Wenju; Xie, Hongtu

    2003-12-01

    Using encapsulation techniques to coat easily soluble fertilizers is an important way to improve fertilizer use efficiency while reduce environmental hazards. Based on a wide range of literature collection on coated fertilizer research, the theories, processes, and characters of nutrient controlled-release from coated fertilizer were discussed, and the factors affecting nutrient controlled-release and the mathematical simulations on it were reviewed. The main tendencies related to this research in China were also put forward.

  1. Local delivery of nitric oxide: targeted delivery of therapeutics to bone and connective tissues

    PubMed Central

    Nichols, Scott P.; Storm, Wesley L.; Koh, Ahyeon; Schoenfisch, Mark H.

    2012-01-01

    Non-invasive treatment of injuries and disorders affecting bones and connective tissue is a significant challenge facing the medical community. A treatment route that has recently been proposed is nitric oxide (NO) therapy. Nitric oxide plays several roles in physiology with many conditions lacking adequate levels of NO. As NO is a radical, localized delivery via NO donors is essential to promoting biological activity. Herein, we review current literature related to therapeutic NO delivery in the treatment of bone, skin and tendon repair. PMID:22433782

  2. Cell-Mediated Delivery of Nanoparticles: Taking Advantage of Circulatory Cells to Target Nanoparticles

    PubMed Central

    Anselmo, Aaron C.; Mitragotri, Samir

    2014-01-01

    Cellular hitchhiking leverages the use of circulatory cells to enhance the biological outcome of nanoparticle drug delivery systems, which often suffer from poor circulation time and limited targeting. Cellular hitchhiking utilizes the natural abilities of circulatory cells to: (i) navigate the vasculature while avoiding immune system clearance, (ii) remain relatively inert until needed and (iii) perform specific functions, including nutrient delivery to tissues, clearance of pathogens, and immune system surveillance. A variety of synthetic nanoparticles attempt to mimic these functional attributes of circulatory cells for drug delivery purposes. By combining the advantages of circulatory cells and synthetic nanoparticles, many advanced drug delivery systems have been developed that adopt the concept of cellular hitchhiking. Here, we review the development and specific applications of cellular hitchhiking-based drug delivery systems. PMID:24747161

  3. Using a registry to improve immunization delivery.

    PubMed

    Kairys, Steven W; Gubernick, Ruth S; Millican, Adrienne; Adams, William G

    2006-07-01

    The NJIPSP was successful in encouraging a group of small urban practices to adopt the use of immunization registry and to transform immunization delivery from a mechanistic well-child service to a visible, monitored process of care. The project represents a unique combination of technology, public-private collaboration, and well-established quality improvement techniques. The change process involved the whole office as a team in adopting new immunization delivery roles and services. The greatest barrier to acceptance of the registry was (and continues to be) the need for manual data entry as the primary source of data collection, rather than electronic data transfer from other systems. The manual entry of data was labor intensive for participating practices and affected data measurement. Despite this barrier, however, the majority of practices substantially improved the quality of their immunization delivery practices in multiple areas. The rapid movement of primary care practices toward some form of electronic record may reduce this barrier and increase the percentage of practices willing to use a community registry. Practices that engaged collectively in the change process gained momentum from the group effort. Equally important was the public health partnership that helped identify and reduce improvement obstacles. Sustainability of practice-based immunization changes will rely, in part, on the registry's ease of use and the continued visibility of public health at the practice level. Active practice level collaboration by public health adds great value to change efforts. We believe that the best possible immunization delivery relies on both technology (registries and the EMR) and effective office systems. Projects like the NJIPSP are models for systems that integrate technology, practice change, and quality improvement, and their success has the potential to foster the spread of this approach to other primary care practices (especially in New Jersey). The

  4. Managing urban nutrient biogeochemistry for sustainable urbanization.

    PubMed

    Lin, Tao; Gibson, Valerie; Cui, Shenghui; Yu, Chang-Ping; Chen, Shaohua; Ye, Zhilong; Zhu, Yong-Guan

    2014-09-01

    Urban ecosystems are unique in the sense that human activities are the major drivers of biogeochemical processes. Along with the demographic movement into cities, nutrients flow towards the urban zone (nutrient urbanization), causing the degradation of environmental quality and ecosystem health. In this paper, we summarize the characteristics of nutrient cycling within the urban ecosystem compared to natural ecosystems. The dynamic process of nutrient urbanization is then explored taking Xiamen city, China, as an example to examine the influence of rapid urbanization on food sourced nitrogen and phosphorus metabolism. Subsequently, the concept of a nutrient footprint and calculation method is introduced from a lifecycle perspective. Finally, we propose three system approaches to mend the broken biogeochemical cycling. Our study will contribute to a holistic solution which achieves synergies between environmental quality and food security, by integrating technologies for nutrient recovery and waste reduction.

  5. Plant species differ in early seedling growth and tissue nutrient responses to arbuscular and ectomycorrhizal fungi.

    PubMed

    Holste, Ellen K; Kobe, Richard K; Gehring, Catherine A

    2017-04-01

    Experiments with plant species that can host both arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF) are important to separating the roles of fungal type and plant species and understanding the influence of the types of symbioses on plant growth and nutrient acquisition. We examined the effects of mycorrhizal fungal type on the growth and tissue nutrient content of two tree species (Eucalyptus grandis and Quercus costaricensis) grown under four nutrient treatments (combinations of low versus high nitrogen (N) and phosphorus (P) with different N:P ratios) in the greenhouse. Trees were inoculated with unidentified field mixtures of AMF or EMF species cultivated on root fragments of AMF- or EMF-specific bait plants. In E. grandis, inoculation with both AMF and EMF positively affected belowground plant dry weight and negatively affected aboveground dry weight, while only inoculation with AMF increased tissue nutrient content. Conversely, Q. costaricensis dry weight and nutrient content did not differ significantly among inoculation treatments, potentially due to its dependence on cotyledon reserves for growth. Mineral nutrition of both tree species differed with the ratio of N to P applied while growth did not. Our results demonstrate that both tree species' characteristics and the soil nutrient environment can affect how AMF and EMF interact with their host plants. This research highlights the importance of mycorrhizal fungal-tree-soil interactions during early seedling growth and suggests that differences between AMF and EMF associations may be crucial to understanding forest ecosystem functioning.

  6. Nutrient Requirements for High Stress Environments

    DTIC Science & Technology

    1988-04-20

    specific nutrients to prevent stress related performance decrements. NUTRIENT REQUIREMENTS *The familiar concept of the biological dose - response curve *"’’ that...depicts a dose - response curve for a hypothet- ical essential nutrient that is related to a physiological function. I would like to emphasize that such...dose-response curves are representative of a population; an individual’s VI. dose - response curve may be broader or steeper, and possess a lower or

  7. Control of microorganisms in flowing nutrient solutions

    NASA Astrophysics Data System (ADS)

    Evans, R. D.

    1994-11-01

    Controlling microorganisms in flowing nutrient solutions involves different techniques when targeting the nutrient solution, hardware surfaces in contact with the solution, or the active root zone. This review presents basic principles and applications of a number of treatment techniques, including disinfection by chemicals, ultrafiltration, ultrasonics, and heat treatment, with emphasis on UV irradiation and ozone treatment. Procedures for control of specific pathogens by nutrient solution conditioning also are reviewed.

  8. Control of microorganisms in flowing nutrient solutions.

    PubMed

    Evans, R D

    1994-11-01

    Controlling microorganisms in flowing nutrient solutions involves different techniques when targeting the nutrient solution, hardware surfaces in contact with the solution, or the active root zone. This review presents basic principles and applications of a number of treatment techniques, including disinfection by chemicals, ultrafiltration, ultrasonics, and heat treatment, with emphasis on UV irradiation and ozone treatment. Procedures for control of specific pathogens by nutrient solution conditioning also are reviewed.

  9. Optimizing drugs for local delivery.

    PubMed

    Collingwood, S; Lock, R; Searcey, M

    2009-12-01

    An international panel of speakers together with approximately 70 delegates were brought together by The Society for Medicines Research's symposium on Optimising Drugs for Local Delivery, held on June 11, 2009 at the Novartis Institutes for Biomedical Research, Horsham, UK. The focus of the conference was on the delivery of drugs direct to the site of action and the consequences of this delivery route on delivery technologies, formulation science and molecular design.

  10. Microprocessor controlled transdermal drug delivery.

    PubMed

    Subramony, J Anand; Sharma, Ashutosh; Phipps, J B

    2006-07-06

    Transdermal drug delivery via iontophoresis is reviewed with special focus on the delivery of lidocaine for local anesthesia and fentanyl for patient controlled acute therapy such as postoperative pain. The role of the microprocessor controller in achieving dosimetry, alternating/reverse polarity, pre-programmed, and sensor-based delivery is highlighted. Unique features such as the use of tactile signaling, telemetry control, and pulsatile waveforms in iontophoretic drug delivery are described briefly.

  11. Nutrient-Specific Foraging in Invertebrate Predators

    NASA Astrophysics Data System (ADS)

    Mayntz, David; Raubenheimer, David; Salomon, Mor; Toft, Søren; Simpson, Stephen J.

    2005-01-01

    Many herbivores and omnivores adjust their food selection behavior to regulate the intake of multiple nutrients. Carnivores, however, are generally assumed to optimize the rate of prey capture rather than select prey according to nutrient composition. We showed experimentally that invertebrate predators can forage selectively for protein and lipids to redress specific nutritional imbalances. This selection can take place at different stages of prey handling: The predator may select among foods of different nutritional composition, eat more of a prey if it is rich in nutrients that the predator is deficient in, or extract specific nutrients from a single prey item.

  12. Nutrient availability moderates transpiration in Ehrharta calycina.

    PubMed

    Cramer, Michael D; Hoffmann, Vera; Verboom, G Anthony

    2008-01-01

    Transpiration-driven 'mass-flow' of soil-water can increase nutrient flow to the root surface. Here it was investigated whether transpiration could be partially regulated by nutrient status. Seeds of Ehrharta calycina from nine sites across a rainfall gradient were supplied with slow-release fertilizer dibbled into the sand surrounding the roots and directly available through interception, mass-flow and diffusion (dubbed 'interception'), or sequestered behind a 40-microm mesh and not directly accessible by the roots, but from which nutrients could move by diffusion or mass-flow (dubbed 'mass-flow'). Although mass-flow plants were significantly smaller than interception plants as a consequence of nutrient limitation, they transpired 60% faster, had 90% higher photosynthesis relative to transpiration (A/E), and 40% higher tissue P, Ca and Na concentrations than plants allowed to intercept nutrients directly. Tissue N and K concentrations were similar for interception and mass-flow plants. Transpiration was thus higher in the nutrient-constrained 'mass-flow' plants, increasing the transport of nutrients to the roots by mass-flow. Transpiration may have been regulated by N availability, resulting in similar tissue concentration between treatments. It is concluded that, although transpiration is a necessary consequence of photosynthetic CO(2) uptake in C(3) plants, plants can respond to nutrient limitation by varying transpiration-driven mass-flow of nutrients.

  13. Nutrient and phytoplankton analysis of a Mediterranean coastal area.

    PubMed

    Sebastiá, M T; Rodilla, M

    2013-01-01

    Identifying and quantifying the key anthropogenic nutrient input sources are essential to adopting management measures that can target input for maximum effect in controlling the phytoplankton biomass. In this study, three systems characterized by distinctive main nutrient sources were sampled along a Mediterranean coast transect. These sources were groundwater discharge in the Ahuir area, the Serpis river discharge in the Venecia area, and a submarine wastewater outfall 1,900 m from the coast. The study area includes factors considered important in determining a coastal area as a sensitive area: it has significant nutrient sources, tourism is a major source of income in the region, and it includes an area of high water residence time (Venecia area) which is affected by the harbor facilities and by wastewater discharges. We found that in the Ahuir and the submarine wastewater outfall areas, the effects of freshwater inputs were reduced because of a greater water exchange with the oligotrophic Mediterranean waters. On the other hand, in the Venecia area, the highest levels of nutrient concentration and phytoplankton biomass were attributed to the greatest water residence time. In this enclosed area, harmful dinoflagellates were detected (Alexandrium sp. and Dinophysis caudata). If the planned enlargement of the Gandia Harbor proceeds, it may increase the vulnerability of this system and provide the proper conditions of confinement for the dinoflagellate blooms' development. Management measures should first target phosphorus inputs as this is the most potential-limiting nutrient in the Venecia area and comes from a point source that is easier to control. Finally, we recommend that harbor environmental management plans include regular monitoring of water quality in adjacent waters to identify adverse phytoplankton community changes.

  14. Birds transport nutrients to fragmented forests in an urban landscape.

    PubMed

    Fujita, Motoko; Koike, Fumito

    2007-04-01

    The influence of urbanization on nutrient cycling is vaguely known. Here we document that birds, especially those increasing in urban areas (such as crows, Corvus macrorhynchos and C. corone), affect nutrient cycles. Using fecal traps, we measured phosphorus (P) and nitrogen (N) input from the excrement of birds in fragmented forests in an urban landscape. Sources of avian feces were examined on the basis of carbon (C), N, and P percentages and stable isotopes of delta15N and delta13C. Nitrogen and P input was aggregated in the urban landscape, being especially high at the forest where crows roosted during winter. The annual P input due to bird droppings (range 0.068-0.460 kg x ha(-1) x yr(-1); mean 0.167 kg x ha(-1) x yr(-1)) was 12.4% of the total of other pathways in typical forests and 52.9% in the evergreen forest where crows roosted. The annual N input due to bird droppings (range 0.44-3.49 kg x ha(-1) x yr(-1); mean 1.15 kg x ha(-1) x yr(-1)) was 5.2% of the total of other pathways in typical forests and 27.0% in the evergreen forest used by roosting crows. Expected sources of nutrients in feces included insects in the breeding season, fruits in autumn, and mammals and birds in winter. Stable isotopes suggested that the source of nutrients in forests used by roosting crows was from outside the forest. Therefore, birds played a significant role as transporters of nutrients from garbage (including fish, livestock, and/or C4 plants such as corn, with high delta15N and delta13C) in residential and business areas to fragmented evergreen forests, especially near their winter roosts.

  15. Influence of Physiological Stress on Nutrient Stoichiometry in Larval Amphibians.

    PubMed

    Kirschman, Lucas J; Haslett, Savhannah; Fritz, Kelley A; Whiles, Matt R; Warne, Robin W

    2016-01-01

    Exposure to environmental stressors alters animal phenotypes as well as nutrient metabolism, assimilation, and excretion. While stress-induced shifts in nutrient processes are known to alter organismal carbon (C) and nitrogen (N) stoichiometry, there has been little exploration of how environmental factors influence phosphorous (P). A better understanding of how P cycling varies with animal physiological state may provide insight into across-scale processes, because P is essential to animal function and ecological processes such as production and decomposition. We tested the effects of predator stress and exogenous glucocorticoids on C∶N∶P stoichiometry of larval amphibians. Glucocorticoids altered nutrient stoichiometry, apparently by modulating ossification and renal function. This reduced whole-body P and significantly increased N∶P. Additionally, elevated glucocorticoids caused a long-term reduction in P excretion. This reduction may reflect an initial unmeasured loss of P that glucocorticoids induce over acute timescales. In contrast, exposure to predator cues had no effect on larval C∶N∶P stoichiometry, which highlights that different stressors have varied effects on the endocrine stress response. Predation, in particular, is ubiquitous in the environment; thus, larvae responding to predators have conserved mechanisms that likely prevent or minimize physiological disruption. These results demonstrate the differing physiological roles of N and P, distinct nutrient demands associated with amphibian metamorphosis, and the contrasting effects that different environmental factors have on the physiological stress response. Our results also suggest that anthropogenic changes to the environment that induce chronic stress in amphibians could affect the biogeochemistry of nutrient-poor environments where they may act as keystone species.

  16. Comparison of nutrient intake, life style variables, and pregnancy outcomes by the depression degree of pregnant women.

    PubMed

    Bae, Hyun Sook; Kim, Sun Young; Ahnv, Hong Seok; Cho, Yeon Kyung

    2010-08-01

    The aim of this study was to analyse effects that the degree of depression have on the life style variables, nutrient intake, iron indices and pregnancy outcome. Subjects were 114 pregnant women who were receiving prenatal care at a hospital in Seoul. We collected data for general characteristics and lifestyle variables from general survey instrument and for depression score from the questionnaire on depression. Dietary intakes of subjects were estimated by 24 hour dietary recall method. Also we analysed iron indices and pregnancy outcomes. We classified subjects by 10 point, which was the average depression score, into two groups [Low depression score group (LS) : High depression score group (HS)]. As to the intakes of total calcium, plant-calcium, plant-iron, potassium, total folate and dietary folate, LS group was far higher than HS group (P < 0.05, P < 0.05, P < 0.01, P < 0.001, P < 0.05, and P < 0.01, respectively). As to pre-pregnancy alcohol drinking, LS group had 41.9% in non-drinker, which was far higher than 28% in HS group in non-drinker (P < 0.05). As for drinking coffee during pre-pregnancy, pregnant women who don't drink coffee in LS group took 43.6%, which was higher than 38% in HS group (P < 0.01). Regarding delivery type, the cesarean section in LS group (18%) was significantly lower than that in HS group (45%) (P < 0.01). Bivariate analysis showed that birth weight was significantly associated with the gestational age (P < 0.01). The pregnant women with higher depression score tended to have undesirable life habit, which might affect negative pregnancy outcomes. A better understanding of how depression and intake of nutrients work together to modulate behavior will be benefit nutritional research.

  17. The role of light availability and herbivory on algal responses to nutrient enrichment in a riparian wetland, Alaska.

    PubMed

    Rober, Allison R; Stevenson, R Jan; Wyatt, Kevin H

    2015-06-01

    We investigated how the relative availability of solar radiation in the presence or absence of grazing alters the ability of benthic algae to respond to nutrient enrichment in an Alaskan marsh. We used a factorial mesocosm experiment that included nutrient enrichment (enriched or control), grazing (grazed or ungrazed), and light (unshaded or shaded) to simulate shading by macrophytes early and late in the growing season, respectively. We found stronger effects of grazers and nutrients compared to light on benthic algal biomass and taxonomic composition. Algal biomass increased in nutrient-enriched treatments and was reduced by grazing. Shading did not have an effect on algal biomass or taxonomic composition, but the concentration of chl a per algal biovolume increased with shading, demonstrating the ability of algae to compensate for changes in light availability. Algal taxonomic composition was more affected by grazer presence than nutrients or light. Grazer-resistant taxa (basal filaments of Stigeoclonium) were replaced by diatoms (Nitzschia) and filamentous green algae (Ulothrix) when herbivores were removed. The interacting and opposing influences of nutrients and grazing indicate that the algal community is under dual control from the bottom-up (nutrient limitation) and from the top-down (consumption by herbivores), although grazers had a stronger influence on algal biomass and taxonomic composition than nutrient enrichment. Our results suggest that low light availability will not inhibit the algal response to elevated nutrient concentrations expected with ongoing climate change, but grazers rapidly consume algae following enrichment, masking the effects of elevated nutrients on algal production.

  18. Quantitative Models Describing Past and Current Nutrient Fluxes and Associated Ecosystem Level Responses in the Narragansett Bay Ecosystem

    EPA Science Inventory

    Multiple drivers, including nutrient loading and climate change, affect the Narragansett Bay ecosystem in Rhode Island/Massachusetts, USA. Managers are interested in understanding the timing and magnitude of these effects, and ecosystem responses to restoration actions. To provid...

  19. Synthetic Tumor Networks for Screening Drug Delivery Systems

    PubMed Central

    Prabhakarpandian, Balabhaskar; Shen, Ming-Che; Nichols, Joseph B.; Garson, Charles J.; Mills, Ivy R.; Matar, Majed M.; Fewell, Jason G.; Pant, Kapil

    2015-01-01

    Tumor drug delivery is a complex phenomenon affected by several elements in addition to drug or delivery vehicle’s physico-chemical properties. A key factor is tumor microvasculature with complex effects including convective transport, high interstitial pressure and enhanced vascular permeability due to the presence of “leaky vessels”. Current in vitro models of the tumor microenvironment for evaluating drug delivery are oversimplified and, as a result, show poor correlation with in vivo performance. In this study, we report on the development of a novel microfluidic platform that models the tumor microenvironment more accurately, with physiologically and morphologically realistic microvasculature including endothelial cell lined leaky capillary vessels along with 3D solid tumors. Endothelial cells and 3D spheroids of cervical tumor cells were co-cultured in the networks. Drug vehicle screening was demonstrated using GFP gene delivery by different formulations of nanopolymers. The synthetic tumor network was successful in predicting in vivo delivery efficiencies of the drug vehicles. The developed assay will have critical applications both in basic research, where it can be used to develop next generation delivery vehicles, and in drug discovery where it can be used to study drug transport and delivery efficacy in realistic tumor microenvironment, thereby enabling drug compound and/or delivery vehicle screening. PMID:25599856

  20. NUTRIENT UPTAKE: A Microcomputer Program to Predict Nutrient Absorption from Soil by Roots.

    ERIC Educational Resources Information Center

    Oates, Kenneth; Barber, S. A.

    1987-01-01

    Discusses the use of a computer program designed to solve the mathematical model associated with soil nutrient uptake by plant roots and to predict the nutrient uptake. Describes a user-friendly personal computer version of this program. (TW)

  1. Variable primary producer responses to nutrient and temperature manipulations in mesocosms: temperature usually trumps nutrient effects

    EPA Science Inventory

    Mesocosm experiments have been used to evaluate the impacts of nutrient loading on estuarine plant communities in order to develop nutrient response relationships. Mesocosm eutrophication studies tend to focus on long residence time systems. In the Pacific Northwest, many estuari...

  2. Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia.

    PubMed

    van der Wulp, Simon A; Damar, Ario; Ladwig, Norbert; Hesse, Karl-J

    2016-09-30

    The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377m(3)s(-1) entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174tons and 14 to 60tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics.

  3. Nutrients stimulate leaf breakdown rates and detritivore biomass: Bottom-up effects via heterotrophic pathways

    USGS Publications Warehouse

    Greenwood, J.L.; Rosemond, A.D.; Wallace, J.B.; Cross, W.F.; Weyers, H.S.

    2007-01-01

    Most nutrient enrichment studies in aquatic systems have focused on autotrophic food webs in systems where primary producers dominate the resource base. We tested the heterotrophic response to long-term nutrient enrichment in a forested, headwater stream. Our study design consisted of 2 years of pretreatment data in a reference and treatment stream and 2 years of continuous nitrogen (N) + phosphorus addition to the treatment stream. Studies were conducted with two leaf species that differed in initial C:N, Rhododendron maximum (rhododendron) and Acer rubrum (red maple). We determined the effects of nutrient addition on detrital resources (leaf breakdown rates, litter C:N and microbial activity) and tested whether nutrient enrichment affected macroinvertebrate consumers via increased biomass. Leaf breakdown rates were ca. 1.5 and 3?? faster during the first and second years of enrichment, respectively, in the treatment stream for both leaf types. Microbial respiration rates of both leaf types were 3?? higher with enrichment, and macroinvertebrate biomass associated with leaves increased ca. 2-3?? with enrichment. The mass of N in macroinvertebrate biomass relative to leaves tended to increase with enrichment up to 6?? for red maple and up to 44?? for rhododendron leaves. Lower quality (higher C:N) rhododendron leaves exhibited greater changes in leaf nutrient content and macroinvertebrate response to nutrient enrichment than red maple leaves, suggesting a unique response by different leaf species to nutrient enrichment. Nutrient concentrations used in this study were moderate and equivalent to those in streams draining watersheds with altered land use. Thus, our results suggest that similarly moderate levels of enrichment may affect detrital resource quality and subsequently lead to altered energy and nutrient flow in detrital food webs. ?? 2006 Springer-Verlag.

  4. Modelling phytoplankton succession and nutrient transfer along the Scheldt estuary (Belgium, The Netherlands)

    NASA Astrophysics Data System (ADS)

    Gypens, N.; Delhez, E.; Vanhoutte-Brunier, A.; Burton, S.; Thieu, V.; Passy, P.; Liu, Y.; Callens, J.; Rousseau, V.; Lancelot, C.

    2013-12-01

    The freshwater (RIVE) and the marine (MIRO) biogeochemical models were coupled to a 1D hydro-sedimentary model to describe contemporary phytoplankton succession and nutrient transfers in the macrotidal Scheldt estuary (BE/NL) affected by anthropogenic nutrient loads. The 1D-RIVE-MIRO model simulations are performed between Ghent and Vlissingen and the longitudinal estuarine profiles are validated by visual and statistical comparison with physico-chemical and phytoplankton observations available for the year 2006. Results show the occurrence of two distinct spatial phytoplankton blooms in the upper and lower estuary, suggesting that neither the freshwater nor the marine phytoplankton gets over the maximum turbidity zone (MTZ) at the saline transition. Sensitivity tests performed to understand how changing conditions (salinity, turbidity and nutrients) along the estuary are controlling this bimodal spatial phytoplankton distribution identify salinity and light availability as the key drivers while the grazing pressure and nutrient limitation play a negligible role. Additional tests with varying salinity-resistant (euryhaline) species in the freshwater assemblage conclude that the presence (or absence) of euryhalines determines the magnitude and the spreading of freshwater and marine phytoplankton blooms in the estuary. Annual nutrient budgets estimated from 1D-RIVE-MIRO simulations show that biological activities have a negligible impact on nutrient export but modify the speciation of nutrients exported to the coastal zone towards inorganic forms, thus directly available to phytoplankton. The implementation of nutrient reduction options (upgrading of waste water treatment plants, conversion to organic farming) on the Scheldt watershed influences the whole estuary and affects both the magnitude and the speciation of nutrients exported to the coastal zone with expected impact on coastal phytoplankton dynamic.

  5. Overview: Cross-habitat flux of nutrients and detritus

    USGS Publications Warehouse

    Vanni, M.J.; DeAngelis, D.L.; Schindler, D.E.; Huxel, G.R.; Polis, G.A.; Power, M.E.; Huxel, G.R.

    2004-01-01

    Ecologists have long known that all ecosystems receive considerable quantities of materials from outside their boundaries (e.g., Elton 1927), and quantifying the magnitude of such fluxes has long been a central tenet of ecosystem ecology (e.g., Odum 1971). Thus, one might think that the consequences of such fluxes for food webs would be well understood. However, food webs have traditionally been viewed as if they were isolated from surrounding habitats, a habit that has been particularly persistent in the modeling of food webs. When fluxes from the outside have been considered, they have largely been restricted to constant inputs directly affecting the base of the food web (e.g., solar energy or nutrients), and usually only such issues as their effects on equilibrium conditions have been considered (e.g., the well-known relationships between nutrient inputs and average densities of various food web members).

  6. Recovery of three arctic stream reaches from experimental nutrient enrichment

    USGS Publications Warehouse

    Benstead, J.P.; Green, A.C.; Deegan, Linda A.; Peterson, B.J.; Slavik, K.; Bowden, W.B.; Hershey, A.E.

    2007-01-01

    1. Nutrient enrichment and resulting eutrophication is a widespread anthropogenic influence on freshwater ecosystems, but recovery from nutrient enrichment is poorly understood, especially in stream environments. We examined multi-year patterns in community recovery from experimental low-concentration nutrient enrichment (N + P or P only) in three reaches of two Arctic tundra streams (Kuparuk River and Oksrukuyik Creek) on the North Slope of Alaska (U.S.A.). 2. Rates of recovery varied among community components and depended on duration of enrichment (2-13 consecutive growing seasons). Biomass of epilithic algae returned to reference levels rapidly (within 2 years), regardless of nutrients added or enrichment duration. Aquatic bryophyte cover, which increased greatly in the Kuparuk River only after long-term enrichment (8 years), took 8 years of recovery to approach reference levels, after storms had scoured most remnant moss in the recovering reach. 3. Multi-year persistence of bryophytes in the Kuparuk River appeared to prevent recovery of insect populations that had either been positively (e.g. the mayfly Ephemerella, most chironomid midge taxa) or negatively (e.g. the tube-building chironomid Orthocladius rivulorum) affected by this shift in dominant primary producer. These lags in recovery (of >3 years) were probably driven by the persistent effect of bryophytes on physical benthic habitat. 4. Summer growth rates of Arctic grayling (both adults and young-of-year) in Oksrukuyik Creek (fertilised for 6 years with no bryophyte colonisation), which were consistently increased by nutrient addition, returned to reference rates within 1-2 years. 5. Rates of recovery of these virtually pristine Arctic stream ecosystems from low-level nutrient enrichment appeared to be controlled largely by duration of enrichment, mediated through physical habitat shifts caused by eventual bryophyte colonisation, and subsequent physical disturbance that removed bryophytes. Nutrient

  7. Race, genes and preterm delivery.

    PubMed Central

    Fiscella, Kevin

    2005-01-01

    High rates of preterm delivery (PTD) among African Americans are the leading cause of excess infant mortality among African Americans. Failure to fully explain racial disparity in PTD has led to speculation that genetic factors might contribute to this disparity. Current evidence suggests that genetic factors contribute to PTD, but this does not imply that genetic factors contribute to racial disparity in PTD. Environmental factors clearly contribute to PTD. Many of these factors acting over a women's life prior to pregnancy disproportionately affect African Americans and contribute significantly to racial disparity in PTD. Thus, inferring genetic contribution to racial disparity in PTD by attempting to control for environmental factors measured at a single point in time is flawed. There is emerging evidence of gene-environment interactions for PTD, some of which disproportionately affect African Americans. There is also evidence of racial differences in the prevalence of polymorphisms potentially related to PTD. However, to date there is no direct evidence that these differences contribute significantly to racial disparity in PTD. Given the complexity of polygenic conditions such as PTD, the possibility of any single gene contributing substantially to racial disparity in PTD seems remote. PMID:16334498

  8. Maternal Dietary Nutrient Intake and Its Association  with Preterm Birth: A Case-control Study in Beijing,  China.

    PubMed

    Zhang, Yan; Zhou, Hong; Perkins, Anthony; Wang, Yan; Sun, Jing

    2017-03-01

    This study aimed to evaluate dietary nutrient intake among Chinese pregnant women by comparison with Chinese Dietary Reference Intakes (DRIs) and to explore the association between dietary nutrients and preterm birth. A case-control design was conducted in Beijing with 130 preterm delivery mothers in case group and 381 term delivery mothers in control group. Information on mothers' diet was collected using a food frequency questionnaire, and nutrients and energy intakes were subsequently calculated based on DRIs. Multivariate analysis of variance was used to compare the differences between term and preterm groups in relation to dietary nutrients. Dietary nutrient intakes were imbalanced in both groups compared with Chinese DRIs. Preterm delivery mothers had a lower level of fat and vitamin E intake than term delivery mothers (p < 0.05). Multivariate analysis showed lower vitamin E intake in preterm delivery mothers with a prepregnancy BMI < 18.5 kg/m2 (p < 0.05) and higher carbohydrate intake in preterm delivery mothers with prepregnancy BMI ≥ 24 kg/m2 (p < 0.05). An imbalanced diet in both groups and low level of dietary intakes of fat and vitamin E in preterm group suggest health education measures should be taken to improve the dietary quality of pregnant women, especially for those with an abnormal prepregnancy BMI.

  9. Nutrient Models Developments Using Runoff-Nutrient Relationships in an Agricultural Prairie Basin, Manitoba.

    NASA Astrophysics Data System (ADS)

    Mahmood, T. H.; Pomeroy, J. W.; Wheater, H. S.; Elliott, J. A.; Baulch, H. M.; Lindenschmidt, K. E.

    2015-12-01

    Nutrient export to streams and lakes from agricultural activities can result in significant deterioration of water quality and aquatic ecosystem health. In Western Canada, particular concerns arise for prairie agricultural systems, which are dominated by the effects of a cold climate. Insufficient attention has been given to understand the links between cold region watershed responses and nutrient concentration and a robust watershed-scale modeling framework is needed to simulate nutrient concentration and loads. Long-term, field observations of nutrient concentration-runoff relationships were used to develop nutrient concentration models for the Tobacco Creek Model Watershed (TCMW) which drains into the Red River basin. Field observations include streamflow concentrations of N and P at multiple scales from two headwater basins. Distinct nutrient concentration-runoff models for snowmelt, rain on snow (ROS) and rainfall runoff processes were developed from observed runoff-nutrient concentration relationships. Snowmelt runoff had a moderately positive correlation with particulate nutrient concentrations but no correlation with that of dissolved nutrients. ROS runoff had a weak relationship with both particulate and dissolved nutrient concentrations. Rainfall runoff had the strongest positive correlation with particulate nutrient concentrations but no association with that of dissolved nutrients. The modeling approach also identified a clear hysteretic behavior in the relationship between runoff and particulate nutrient concentration during the 2013 snowmelt runoff event at the basin outlet gauge. The models provide insight into the hydrological controls on nutrient export from cold regions watersheds and the strong effects of inter-annual climatic variability. Snowmelt runoff is a reliable exporter of large nutrient loads while nutrient export by rainfall runoff exceeded snowmelt runoff during hydrologically wet summers such as 2002, 2005, 2011 and 2013.

  10. Delivery strategies for antiparasitics.

    PubMed

    Kayser, Oliver; Kiderlen, Albrecht F

    2003-02-01

    Optimisation of drug carrier systems and drug delivery strategies that take into account the peculiarities of individual infectious agents and diseases are key elements of modern drug development. In the following, different aspects of a rational design for antiparasitic drug formulation will be reviewed, covering delivery systems such as nano- and microparticles, liposomes, emulsions and microemulsions, cochleates and bioadhesive macromolecules. Functional properties for each carrier system will be discussed as well as their therapeutic efficacy for parasitic diseases, including leishmaniasis, human African trypanosomiasis, human cryptosporidiosis, malaria and schistosomiasis. Critical issues for the application of drug carrier systems will be discussed, focusing on biopharmaceutical and pathophysiological parameters such as routes of application, improvement of body distribution and targeting intracellularly persisting pathogens.

  11. Pyomyositis after vaginal delivery.

    PubMed

    Gaughan, Eve; Eogan, Maeve; Holohan, Mary

    2011-07-07

    Pyomyositis is a purulent infection of skeletal muscle that arises from haematogenous spread, usually with abscess formation. It can develop after a transient bacteraemia of any cause. This type of infection has never been reported before in the literature after vaginal delivery. A 34-year-old woman had progressive severe pain in the left buttock and thigh and weakness in the left lower limb day 1 post spontaneous vaginal delivery. MRI showed severe oedema of the left gluteus, iliacus, piriformis and adductor muscles of the left thigh and a small fluid collection at the left hip joint. She was diagnosed with pyomyositis. She had fever of 37.9°C immediately postpartum and her risk factors for bacteraemia were a mild IV cannula-associated cellulitis and labour itself. She required prolonged treatment with antibiotics before significant clinical improvement was noted.

  12. Newborn Analgesia Mediated by Oxytocin during Delivery.

    PubMed

    Mazzuca, Michel; Minlebaev, Marat; Shakirzyanova, Anastasia; Tyzio, Roman; Taccola, Giuliano; Janackova, Sona; Gataullina, Svetlana; Ben-Ari, Yehezkel; Giniatullin, Rashid; Khazipov, Rustem

    2011-01-01

    The mechanisms controlling pain in newborns during delivery are poorly understood. We explored the hypothesis that oxytocin, an essential hormone for labor and a powerful neuromodulator, exerts analgesic actions on newborns during delivery. Using a thermal tail-flick assay, we report that pain sensitivity is two-fold lower in rat pups immediately after birth than 2 days later. Oxytocin receptor antagonists strongly enhanced pain sensitivity in newborn, but not in 2-day-old rats, whereas oxytocin reduced pain at both ages suggesting an endogenous analgesia by oxytocin during delivery. Similar analgesic effects of oxytocin, measured as attenuation of pain-vocalization induced by electrical whisker pad stimulation, were also observed in decerebrated newborns. Oxytocin reduced GABA-evoked calcium responses and depolarizing GABA driving force in isolated neonatal trigeminal neurons suggesting that oxytocin effects are mediated by alterations of intracellular chloride. Unlike GABA signaling, oxytocin did not affect responses mediated by P2X3 and TRPV1 receptors. In keeping with a GABAergic mechanism, reduction of intracellular chloride by the diuretic NKCC1 chloride co-transporter antagonist bumetanide mimicked the analgesic actions of oxytocin and its effects on GABA responses in nociceptive neurons. Therefore, endogenous oxytocin exerts an analgesic action in newborn pups that involves a reduction of the depolarizing action of GABA on nociceptive neurons. Therefore, the same hormone that triggers delivery also acts as a natural pain killer revealing a novel facet of the protective actions of oxytocin in the fetus at birth.

  13. Electroresponsive nanoparticles for drug delivery on demand

    NASA Astrophysics Data System (ADS)

    Samanta, Devleena; Hosseini-Nassab, Niloufar; Zare, Richard N.

    2016-04-01

    The potential of electroresponsive conducting polymer nanoparticles to be used as general drug delivery systems that allow electrically pulsed, linearly scalable, and on demand release of incorporated drugs is demonstrated. As examples, facile release from polypyrrole nanoparticles is shown for fluorescein, a highly water-soluble model compound, piroxicam, a lipophilic small molecule drug, and insulin, a large hydrophilic peptide hormone. The drug loading is about 13 wt% and release is accomplished in a few seconds by applying a weak constant current or voltage. To identify the parameters that should be finely tuned to tailor the carrier system for the release of the therapeutic molecule of interest, a systematic study of the factors that affect drug delivery is performed, using fluorescein as a model compound. The parameters studied include current, time, voltage, pH, temperature, particle concentration, and ionic strength. Results indicate that there are several degrees of freedom that can be optimized for efficient drug delivery. The ability to modulate linearly drug release from conducting polymers with the applied stimulus can be utilized to design programmable and minimally invasive drug delivery devices.

  14. Recent Perspectives in Ocular Drug Delivery

    PubMed Central

    Gaudana, Ripal; Jwala, J.; Boddu, Sai H. S.; Mitra, Ashim K.

    2015-01-01

    Anatomy and physiology of the eye makes it a highly protected organ. Designing an effective therapy for ocular diseases, especially for the posterior segment, has been considered as a formidable task. Limitations of topical and intravitreal route of administration have challenged scientists to find alternative mode of administration like periocular routes. Transporter targeted drug delivery has generated a great deal of interest in the field because of its potential to overcome many barriers associated with current therapy. Application of nanotechnology has been very promising in the treatment of a gamut of diseases. In this review, we have briefly discussed several ocular drug delivery systems such as microemulsions, nanosuspensions, nanoparticles, liposomes, niosomes, dendrimers, implants, and hydrogels. Potential for ocular gene therapy has also been described in this article. In near future, a great deal of attention will be paid to develop non-invasive sustained drug release for both anterior and posterior segment eye disorders. A better understanding of nature of ocular diseases, barriers and factors affecting in vivo performance, would greatly drive the development of new delivery systems. Current momentum in the invention of new drug delivery systems hold a promise towards much improved therapies for the treatment of vision threatening disorders. PMID:18758924

  15. Glucose, nitrogen, and phosphate repletion in Saccharomyces c