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Search Results: 1 - 10 of 193478 matches for " Katherine D. Huddersman "
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Pilot-Scale Removal of Trace Steroid Hormones and Pharmaceuticals and Personal Care Products from Municipal Wastewater Using a Heterogeneous Fenton’s Catalytic Process
George Tangyie Chi,John Churchley,Katherine D. Huddersman
International Journal of Chemical Engineering , 2013, DOI: 10.1155/2013/760915
Abstract: The pollution of water sources by endocrine disrupting compounds (EDCs) and pharmaceutical and personal care products (PPCPs) is a growing concern, as conventional municipal wastewater treatment systems are not capable of completely removing these contaminants. A continuous stir tank reactor incorporating a modified polyacrylonitrile (PAN) catalyst and dosed with hydrogen peroxide in a heterogeneous Fenton’s process was used at pilot scale to remove these compounds from wastewater that has undergone previous treatment via a conventional wastewater treatment system. The treatment system was effective at ambient temperature and at the natural pH of the wastewater. High levels of both natural and synthetic hormones (EDCs) and PPCPs were found in the effluent after biological treatment of the wastewater. The treatment system incorporating the modified PAN catalyst/H2O2 decomposed >90% of the EDCs and >40% of PPCPs using 200?mgL?1 H2O2, 3?hr residence time. The estrogenic potency EE2-EQ was removed by 82.77%, 91.36%, and 96.13% from three different wastewater treatment plants. BOD was completely removed (below detection limits); 30%–40% mineralisation was achieved and turbidity reduced by more than 68%. There was a <4% loss in iron content on the catalyst over the study period, suggesting negligible leaching of the catalyst. 1. Introduction Endocrine disrupting compounds (EDCs) which include natural sex hormones such as estrone—E1 and 17 β-estradiol—E2 produced by humans and animals as well as some synthetic estrogens such as 17 α-ethinylestradiol (EE2) used for contraception purposes are able to produce endocrine disruption in living organisms at trace concentrations (nanogram per litre levels) [1, 2]. EDCs have been attributed as a cause of reproductive disturbance in humans and wildlife such as feminisation of fish, developmental abnormalities, and demasculinisation of alligators [3]. Pharmaceutical products such as antibiotics, blood lipid regulators, analgesics, nonsteroidal anti-inflammatory drugs, antidepressants, antiepileptics, impotence drugs, tranquilizers, and many personal care products such as fragrances, soaps, preservatives, and disinfectants (generally called pharmaceutical and personal care products (PPCPs)) have different modes of action, toxicity, and effects on nontarget organisms [4]. EDCs and PPCPs are released into the environment by humans, animals, and industry, mainly through sewage treatment systems before reaching the receiving bodies (soil, surface water, sediment, and groundwater) [2]. Municipal wastewater treatment plants are
The World Health Organization/World Bank’s First World Report on Disability
Katherine D. Seelman
International Journal of Telerehabilitation , 2011, DOI: 10.5195/ijt.2011.6076
Abstract: In June, 2011 at the United Nations (UN) in New York City, the World Health Organization (WHO) and the World Bank launched the first World Report on Disability. This short overview of the Report provides information about its purpose, development and content, intended audiences, and outcomes. Special attention is directed to the sections of the Report which address telerehabilitation and information and communication technology.
Vitamin D: Are We Ready to Supplement for Breast Cancer Prevention and Treatment?
Katherine D. Crew
ISRN Oncology , 2013, DOI: 10.1155/2013/483687
Vitamin D: Are We Ready to Supplement for Breast Cancer Prevention and Treatment?
Katherine D. Crew
ISRN Oncology , 2013, DOI: 10.1155/2013/483687
Abstract: Vitamin D deficiency is a potentially modifiable risk factor that may be targeted for breast cancer prevention and treatment. Preclinical studies support various antitumor effects of vitamin D in breast cancer. Numerous observational studies have reported an inverse association between vitamin D status, including circulating 25-hydroxyvitamin D (25(OH)D) levels, and breast cancer risk. The relationship between vitamin D and mammographic density, a strong predictor of breast cancer risk, remains unclear. Studies analyzing the link between genetic polymorphisms in vitamin D pathway genes and breast cancer incidence and prognosis have yielded inconsistent results. Vitamin D deficiency among breast cancer patients has been associated with poorer clinical outcomes and increased mortality. Despite a number of clinical trials of vitamin D supplementation, the efficacy, optimal dosage of vitamin D, and target blood level of 25(OH)D for breast cancer prevention have yet to be determined. Even with substantial literature on vitamin D and breast cancer, future studies need to focus on gaining a better understanding of the biologic effects of vitamin D in breast tissue. Despite compelling data from experimental and observational studies, there is still insufficient data from clinical trials to make recommendations for vitamin D supplementation for breast cancer prevention or treatment. 1. Introduction Breast cancer confers significant morbidity and mortality among women in the United States. Due to the magnitude of this disease, considerable research effort has been directed toward identifying breast cancer risk factors to target for prevention. However, relatively few modifiable lifestyle and environmental factors have been associated with reduced breast cancer risk. Chemoprevention refers to altering the carcinogenesis process with a drug intervention. The selective estrogen receptor modulators (SERMs), tamoxifen [1] and raloxifene [2], and aromatase inhibitor (AI), exemestane [3], have been shown to reduce breast cancer incidence. These antiestrogens are the only drugs that have been approved by the USA Food and Drug Administration for breast cancer prevention in high-risk population; however, uptake has been poor in the prevention setting. Due to serious toxicities associated with SERMs, namely, endometrial cancer and thromboembolic disease, and chronic toxicities of AIs, such as hot flashes, arthralgias, and osteoporosis, they have not gained widespread acceptance in the primary prevention setting. In addition, these antiestrogens do not lower the incidence of
A chemical ecological investigation of the allelopathic potential of Lamium amplexicaule and Lamium purpureum  [PDF]
Chelsea D. Jones, Katherine E. Woods, William N. Setzer
Open Journal of Ecology (OJE) , 2012, DOI: 10.4236/oje.2012.24020
Abstract: The overall goal of the project was to test the hypothesis that Lamium amplexicaule and Lamium purpureum, weedy invasive species to North America, use phytotoxic allelochemicals in interplant competition. The chemical compositions of the essential oils from the aerial parts of L. amplexicaule and L. purpureum have been obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The essential oils and several essential oil components have been screened for phytotoxic activity on lettuce (Lactuca sativa) and perennial ryegrass (Lolium perenne) as well as nematocidal activity against Caenorhabditis elegans, brine shrimp (Artemia salina) lethality, and insecticidal activity against the red imported fire ant (Solenopsis invicta × richteri). L. amplexicaule essential oil was composed largely of α-pinene, β- pinene, 1-octen-3-ol, (E)-caryophyllene, and germacrene D, while L. purpureum oil was dominated by α-pinene, β-pinene, 1-octen-3-ol, β-elemene, and germacrene D. Neither essential oil exhibited notable phytotoxicity or lethality against nema-todes, brine shrimp, or fire ants. It is unlikely, therefore, that the allelopathy observed in these Lamium species is due to volatile phytochemical constituents.
Dark Matter: A Primer
Katherine Garrett,Gintaras Dūda
Advances in Astronomy , 2011, DOI: 10.1155/2011/968283
Abstract: Dark matter is one of the greatest unsolved mysteries in cosmology at the present time. About 80% of the Universe's gravitating matter is nonluminous, and its nature and distribution are for the most part unknown. In this paper, we will outline the history, astrophysical evidence, candidates, and detection methods of dark matter, with the goal to give the reader an accessible but rigorous introduction to the puzzle of dark matter. This paper targets advanced students and researchers new to the field of dark matter, and includes an extensive list of references for further study.
Bounding the fractional chromatic number of $K_Δ$-free graphs
Katherine Edwards,Andrew D. King
Computer Science , 2012,
Abstract: King, Lu, and Peng recently proved that for $\Delta\geq 4$, any $K_\Delta$-free graph with maximum degree $\Delta$ has fractional chromatic number at most $\Delta-\tfrac{2}{67}$ unless it is isomorphic to $C_5\boxtimes K_2$ or $C_8^2$. Using a different approach we give improved bounds for $\Delta\geq 6$ and pose several related conjectures. Our proof relies on a weighted local generalization of the fractional relaxation of Reed's $\omega$, $\Delta$, $\chi$ conjecture.
A superlocal version of Reed's Conjecture
Katherine Edwards,Andrew D. King
Computer Science , 2012,
Abstract: Reed's well-known $\omega$, $\Delta$, $\chi$ conjecture proposes that every graph satisfies $\chi \leq \lceil \frac 12(\Delta+1+\omega)\rceil$. The second author formulated a {\em local strengthening} of this conjecture that considers a bound supplied by the neighbourhood of a single vertex. Following the idea that the chromatic number cannot be greatly affected by any particular stable set of vertices, we propose a further strengthening that considers a bound supplied by the neighbourhoods of two adjacent vertices. We provide some fundamental evidence in support, namely that the stronger bound holds in the fractional relaxation and holds for both quasi-line graphs and graphs with stability number two. We also conjecture that in the fractional version, we can push the locality even further.
Clustering, Classification, Discriminant Analysis, and Dimension Reduction via Generalized Hyperbolic Mixtures
Katherine Morris,Paul D. McNicholas
Statistics , 2013,
Abstract: A method for dimension reduction with clustering, classification, or discriminant analysis is introduced. This mixture model-based approach is based on fitting generalized hyperbolic mixtures on a reduced subspace within the paradigm of model-based clustering, classification, or discriminant analysis. A reduced subspace of the data is derived by considering the extent to which group means and group covariances vary. The members of the subspace arise through linear combinations of the original data, and are ordered by importance via the associated eigenvalues. The observations can be projected onto the subspace, resulting in a set of variables that captures most of the clustering information available. The use of generalized hyperbolic mixtures gives a robust framework capable of dealing with skewed clusters. Although dimension reduction is increasingly in demand across many application areas, the authors are most familiar with biological applications and so two of the five real data examples are within that sphere. Simulated data are also used for illustration. The approach introduced herein can be considered the most general such approach available, and so we compare results to three special and limiting cases. Comparisons with several well established techniques illustrate its promising performance.
Comparison of Three Delineation Methods Using the Curve Number Method to Model Runoff  [PDF]
William D. Troolin, Katherine Clancy
Journal of Water Resource and Protection (JWARP) , 2016, DOI: 10.4236/jwarp.2016.811077
Abstract: Digital Elevation Models (DEMs) are spatial grids which are used to automate watershed boundary determination. Sinks are present within most DEMs. In order to easily process the watershed boundary, the sinks are reassigned to elevation equivalent to an adjacent cell. The derived DEM is called a “filled” DEM. Due to its relative simplicity, the use of the “filled” DEM is one of the most widely used methods to delineate watershed boundaries and works well in about 70 percent of the watersheds in the US. In landscapes with internal drainage, sinks may accurately represent these depressions. In this study, we compare two delineation methods that do not fill in sinks to another method that does fill in sinks. We examined ten gaged watersheds in Wisconsin and Minnesota. We found the spatial extent of the watersheds from the three methods were significantly different. To evaluate the delineation methods, we modeled ten runoff events using the Curve Number (CN) method and compared them to USGS gage discharge for each watershed. For small storms we found that there were no significant differences in the modeled runoff for three delineation methods. For large storms, we found the no-fill methods had a smaller error, but overall the difference was insignificant. This research suggests that capturing internal drainage by the delineation does not have much of an impact on the widely used CN model.
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