946 research outputs found

    Poulty Manure Impacts on Water Quality

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    Iowa\u27s egg industry continues to grow each year. In 2001, Iowa became the number one egg producing state in the US, producing 8.69 billion eggs (USDA, 2003; USDA 2002). Iowa broke its record the following year producing 10.1 billion eggs which it topped again in 2003 producing 10.1 billion eggs, thus maintaining its position as number one egg producing state in the US (USDA, 2003; USDA, 2004). With this success comes the added weight of maintaining this status, as well as, managing for all the manure that is generated by being the number one producer. Poultry manure can be a valuable soil amendment for adding organic matter and nutrients to farm fields, but if not managed properly, it can also impact the environment by deteriorating water quality. Lakes, rivers, and streams can receive excessive nutrient loads and be contaminated by surface runoff and subsurface drain water. It is the purpose of this study to gain a better understanding on how poultry manure applied to Iowa soils impacts crop growth, soil nutrients, and water quality

    Toll like receptors play a role in general immunity, eye infection and inflammation : TLRs for nanodelivery

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    Dendritic cells [DCs] are potent antigen presenting cells [APC], which plays a vital role in immune system by detecting and capturing pathogens in the body. DCs perform a pivotal role in induction of T cell response. Regulation of immune response can be achieved by specific antigen [Ag] delivery to DCs. A delivery system that can efficiently target and present Ags to DCs for the purpose of anti-tumour activity is currently a topic of significant research interest. DCs are receiving attention due to their key role in anti cancer host response and due to their adjuvanic property in tumour vaccines. Role of toll like receptors [TLR] in innate immune system and their part in eventual stimulation of adaptive immunity is exploited to develop vaccines. TLR agonists in conjugation with vaccines are shown to increase therapeutic efficacy in some cases. TLRs also play a vital role in protecting the cornea from invading pathogens. Due to adverse effects in the treatment of ocular inflammations, cancer and in viral infections, an alternate approach such as the use of TLRs will solve the inquisitive question regarding side effects. The intended delivery is attained by the use of nanoparticles which in turn leads to prolonged half-life in the body. Co-delivery of Ags, TLRs and immunomodulators using nanoparticles has been demonstrated to elicit potent cellular immune responses and are currently under development of clinically applicable immunisations and vaccines

    E. coli Fate and Transport in Macroporous Soils: Short-Circuiting to the Subsurface

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    Pathogen concentrations in streamflow are commonly reported as a significant cause of water quality degradation throughout the world. Research has begun to attempt to model pathogen fate and transport, primarily through surface runoff mechanisms. A significant component of pathogen movement to streams commonly identified but not explicitly simulated in many models is pathogen movement to the subsurface, which can be important in several scenarios such as tile drainage systems. As colloidal contaminants, pathogens such as E. coli tend to become physically trapped in the soil matrix but can move quickly through soil macropores. In fact, concerns exist about the rapid transport of contaminants, such as pesticides, pathogens, and nutrients, from the soil surface to ground water through macropores. Recent research suggests short-circuiting or direct hydrologic connectivity between macropores and subsurface drains. The objective of this paper is to provide an overview of the current research regarding the fate and transport of E. coli through soil macropores and into subsurface drain systems. This paper reports early results from the first year of a multi-year study funded by the USDA Cooperative State Research, Education, and Extension Service as part of the their National Research Initiative program. Field experiments to document short-circuiting by macropores are described and also laboratory data is presented from soil column experiments, capable of simulating surface-connected macropores, with artificial subsurface drainage boundary conditions. These column studies generated information regarding the importance of directly connected macropores on pathogen transport to subsurface drains

    A microfluidic electroosmotic mixer and the effect of potential and frequency on its mixing efficiency

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    This paper presents the design and numerical simulation of a T-shape microfluidic electroosmotic micromixer. It is equipped with six microelectrodes that are embedded in the side surfaces of the microchannel. The electrode array consists of two sets of three 20 &Acirc;&iquest;m and 60 &Acirc;&iquest;m microelectrodes arranged in the form of two opposing triangles. Numerical analysis of electric potential and frequency effects on mixing efficiency of the micromixer is carried out by means of two sets of simulations. First, the electric potential is kept at 2 V while the frequency is varied within 10-50 Hz. The highest achieved mixing efficiency is 96% at 22 Hz. Next, the frequency is kept at 30 Hz whilst the electric potential is varied within 1-5 V. The best achieved mixing efficiency is 97% at 3 V.<br /

    Survivin Mutant Protects Differentiated Dopaminergic SK-N-SH Cells Against Oxidative Stress

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    Oxidative stress is due to an imbalance of antioxidant/pro-oxidant homeostasis and is associated with the progression of several neurological diseases, including Parkinson's and Alzheimer's disease and amyotrophic lateral sclerosis. Furthermore, oxidative stress is responsible for the neuronal loss and dysfunction associated with disease pathogenesis. Survivin is a member of the inhibitors of the apoptosis (IAP) family of proteins, but its neuroprotective effects have not been studied. Here, we demonstrate that SurR9-C84A, a survivin mutant, has neuroprotective effects against H2O2-induced neurotoxicity. Our results show that H2O2 toxicity is associated with an increase in cell death, mitochondrial membrane depolarisation, and the expression of cyclin D1 and caspases 9 and 3. In addition, pre-treatment with SurR9-C84A reduces cell death by decreasing both the level of mitochondrial depolarisation and the expression of cyclin D1 and caspases 9 and 3. We further show that SurR9-C84A increases the antioxidant activity of GSH-peroxidase and catalase, and effectively counteracts oxidant activity following exposure to H2O2. These results suggest for the first time that SurR9-C84A is a promising treatment to protect neuronal cells against H2O2-induced neurotoxicity

    The Size Function of Galaxy Disks out to z ~ 1 from the Canada-France-Hawaii-Telescope Legacy Survey

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    The formation and growth of galaxy disks over cosmic time is crucial to our understanding of galaxy formation. Despite steady improvements in the size and quality of disk samples over the last decade, many aspects of galaxy disk evolution remain unclear. Using two square degrees of deep, wide-field i'-band imaging from the Canada-France-Hawaii Telescope Legacy Survey, we compute size functions for 6000 disks from z=0.2 to z=1 and explore luminosity and number density evolution scenarios with an emphasis on the importance of selection effects on the interpretation of the data. We also compute the size function of a very large sample of disks from the Sloan Digital Sky Survey to use as a local (z ~ 0.1) comparison. CFHTLS size functions computed with the same fixed luminosity-size selection window at all redshifts exhibit evolution that appears to be best modelled by a pure number density evolution. The z = 0.3 size function is an excellent match to the z = 0.9 one if disks at the highest redshift are a factor of 2.5 more abundant than in the local universe. The SDSS size function would also match the z = 0.9 CFHTLS size function very well with a similar change in number density. On the other hand, the CFHTLS size functions computed with a varying luminosity-size selection window with redshift remain constant if the selection window is shifted by 1.0-1.5 mag towards fainter magnitudes with decreasing redshift. There is a weak dependence on disk scale length with smaller (hh \lesssim 4 kpc) disks requiring more luminosity evolution than larger ones. Given that changes in number density are primarily due to mergers and that current estimates of merger rates below z = 1 are low, luminosity evolution appears to be a more plausible scenario to explain the observations.Comment: 11 pages, 9 figures, Accepted for publication in Ap

    Progress on Azadirachta indica based biopesticides in replacing synthetic toxic pesticides

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    Over the years, extensive use of commercially available synthetic pesticides against phytophagous insects has led to their bioaccumulation in the environment causing increased resistance and reduction in soil biodiversity. Further, 90% of the applied pesticides enter the various environmental resources as a result of run-off, exposing the farmers as well as consumers of the agricultural produce to severe health issues. Therefore, growing attention has been given toward the development of alternate environmentally friendly pesticides/insecticides that would aid an efficient pest management system and also prevent chronic exposures leading to diseases. One such strategy is, the use of neem plant\u27s (Binomial name: Azadirachta indica) active ingredients which exhibit agro-medicinal properties conferring insecticidal as well as immunomodulatory and anti-cancer properties. The most prominent constituent of neem is azadirachtin, which has been established as a pivotal insecticidal ingredient. It acts as an antifeedant, repellent, and repugnant agent and induces sterility in insects by preventing oviposition and interrupting sperm production in males. This review discusses, key neem pesticidal components, their active functional ingredients along with recent strategies on employing nanocarriers, to provide controlled release of the active ingredients and to improve their stability and sustainability

    Temporal Dynamics of Preferential Flow to a Subsurface Drain

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    We conducted a sequential tracer leaching study on a 24.4 by 42.7 m field plot to investigate the temporal behavior of chemical movement to a 1.2-m deep field drain during irrigation and subsequent rainfall events over a 14-d period. The herbicides atrazine [6-chloroN-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine], and alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] along with the conservative tracer Br were applied to a 1-m wide strip, offset 1.5 m laterally from a subsurface drain pipe, immediately before an 11.3-h long, 4.2-mm h−1 irrigation. Three additional conservative tracers, pentafluorobenzoate (PF), o-trifluoromethylbenzoate (TF), and difluorobenzoate (DF) were applied to the strip during the irrigation at 2-h intervals. Breakthrough of Br and the two herbicides occurred within the first 2-h of irrigation, indicating that a fraction of the solute transport was along preferential flow paths. Retardation and attenuation of the herbicides indicated that there was interaction between the chemicals and the soil lining the preferential pathways. The conservative tracers applied during the later stages of irrigation arrived at the subsurface drain much faster than tracers applied earlier. The final tracer, applied 6 h after the start of irrigation (DF), took only 15 min and 1 mm of irrigation water to travel to the subsurface drain. Model simulations using a two-dimensional, convective, and dispersive numerical model without an explicit preferential flow component failed to reproduce Br tracer concentrations in the drain effluent, confirming the importance of preferential flow. This study showed that preferential flow in this soil is not a uniform process during a leaching event
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