6 results
Effect of Bicyclopyrone on Triploid Watermelon in Plasticulture
- Matthew B. Bertucci, Katherine M. Jennings, David W. Monks, David L. Jordan, Jonathan R. Schultheis, Frank J. Louws, Matthew D. Waldschmidt
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- Journal:
- Weed Technology / Volume 32 / Issue 4 / August 2018
- Published online by Cambridge University Press:
- 21 June 2018, pp. 439-443
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Field studies were conducted to determine watermelon tolerance and yield response when treated with bicyclopyrone preplant (PREPLANT), POST, and POST-directed (POST-DIR). Treatments consisted of two rates of bicyclopyrone (37.5 and 50 g ai ha–1), fomesafen (175 g ai ha–1), S-metolachlor (802 g ai ha–1), and a nontreated check. Preplant treatments were applied to formed beds 1 d prior to transplanting and included bicyclopyrone (37.5 and 50 g ha–1) and fomesafen (175 g ha–1), and new polyethylene mulch was subsequently laid above treated beds. POST and POST-DIR treatments were applied 14 ± 1 d after watermelon transplanting and included bicyclopyrone (37.5 and 50 g ha–1) POST and POST-DIR, and S-metolachlor (802 g ai ha–1) POST-DIR. POST-DIR treatments were applied to row middles, ensuring that no herbicide contacted watermelon vines or polyethylene mulch. At 2 wk after transplanting (WAT), 15% foliar bleaching was observed in watermelon treated with bicyclopyrone (50 g ha–1) PRE. At 3 WAT, bicyclopyrone (37.5 and 50 g ha–1) POST caused 16% and 17% foliar bleaching and 8% and 9% crop stunting, respectively. At 4 WAT, initial injury had subsided and bicyclopyrone (37.5 and 50 g ha–1) POST caused 4% and 4% foliar bleaching and 4% and 8% crop stunting, respectively. No symptoms of bleaching or stunting were observed at 6- and 8-WAT ratings. Watermelon total yield, marketable yield, total fruit number, marketable fruit number, and average fruit size were unaffected by herbicide treatments. Therefore, registration of bicyclopyrone (37.5 and 50 g ha–1) PREPLANT, POST, and POST-DIR would offer watermelon producers a safe herbicide option and a novel mode of action for weed management.
Epidemiology of Primary Intracranial Neoplasms in Manitoba, Canada
- G.R. Sutherland, R. Florell, D. Louw, N.W. Choi, A.A.F. Sima
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- Journal:
- Canadian Journal of Neurological Sciences / Volume 14 / Issue 4 / November 1987
- Published online by Cambridge University Press:
- 18 September 2015, pp. 586-592
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The incidence of primary intracranial tumors in Manitoba, Canada was reviewed. From 1980 through 1985,657 tumors were diagnosed. The crude incidence rates were 10.2/100,000 for males and 10.8/100,000 for females. The three most common tumors were: astrocytoma 281 (43%), meningioma 145 (22%), and pituitary adenoma 111 (17%). Average annual incidence rates for all tumors showed a bimodal distribution with one peak in the 0-4 age group (4.2/100,000), and the other in the 60-69 age group (27.2/100,000). For malignant astrocytoma, the age-specific annual incidence rate increased to the seventh decade where it reached a peak of 14.3/100,000. The incidence of benign astrocytoma remained relatively constant with age at 1.1/100,000. The annual incidence of meningioma increased with age up to the eighth decade reaching 7.2/100,000. Of the 145 meningiomas, 56 (39%) were meningotheliomatous, 48 (33%) transitional, 10 (7%) malignant, 7 (5%) fibroblastic, 6 (4%) psammomatous, 3 (2%) angioblastic, and 15(10%) lacked pathologic diagnosis. The annual incidence of pituitary adenoma showed two peaks, the first occurring in the third decade (2.6/100,000) and the second in the eighth decade (3.2/100,000). Although the incidence of meningioma was relatively high, the clinical features and pathologic patterns of these tumors were not unlike those previously reported in the literature.
A Study of Monoamine Metabolism in Human Epilepsy
- D. Louw, G.R. Sutherland, G.B. Glavin, J. Girvin
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- Journal:
- Canadian Journal of Neurological Sciences / Volume 16 / Issue 4 / November 1989
- Published online by Cambridge University Press:
- 18 September 2015, pp. 394-397
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Fourteen patients with intractable epilepsy underwent surgical resection of their epileptogenic focus. Hippocampal and temporal cortical samples were obtained, and subjected to high performance liquid chromatography with electrochemical detection. Levels of 5-hydroxyindoleacetic acid (5-HIAA) in actively spiking temporal cortex were 0.454 ± 0.012 ng/mg (mean ± SEM), contrasting with less actively spiking cortex values of 0.248 ± 0.042 ng/mg and normal literature values, obtained from post-mortem material, of 0.140 ± 0.050 ng/mg. Similarly, homovanillic acid (NVA) levels were significantly increased in epileptic tissue compared to normal literature values. Actively spiking cortex values were 0.172 ± 0.001 pg/mg, less active cortex values were 0.058 ±0.012 pg/mg, and literature values were 0.011 ± 0.002 pg/mg. Although a direct statistical comparison between the data reported here and literature values may not be valid, the findings show a continuum from normal through increasingly active electrode sites, likely reflecting a true biologic phenomena. Similarly, statistically significant increases in 5-HIAA and HVA levels were found in hippocampal tissue, which also showed significantly lower dihydroxyphenylacetic acid levels. We conclude that raised levels of serotonin and dopamine metabolites in actively spiking cortex likely reflect an increase in their turnover, and are an epileptic epiphenomenon. Exaggeration of turnover may represent the “metabolic noise” of epilepsy, rather than a concerted strategy of local or distal neurons to contain an epileptogenic focus.
A first order assessment of the potential radiological impact of foodstuffs grown in a catchment area influenced by mining and mineral processing industries
- J. Barescut, D. Lariviere, T. Stocki, I. Louw, A. Faanhof, D. Kotze, M. Willemse
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- Journal:
- Radioprotection / Volume 46 / Issue 6 / 2011
- Published online by Cambridge University Press:
- 09 January 2012, pp. S213-S222
- Print publication:
- 2011
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Natural radioactivity is associated with the vast mineral resources in South Africa in such concentrations that the radionuclides from the natural uranium and thorium decay series are found to pose concern for public exposure to communities living around these areas. Consumption of water and food is usually the most important route by which natural radionuclides can enter the human body and assessment of natural radionuclide levels in different foods and diets is therefore important to estimate the intake of these radionuclides by man. Sensitive measurement of three major radionuclides (in addition to 238U, 234U, 232Th, 226Ra, 224Ra and 223Ra) is necessary to calculate the estimated annual dose with a high degree of certainty i.e. 230Th, 210Pb and 210Po, while 231Pa, 227Ac and 228Ra also require improved sensitivity. In order to evaluate the yearly dose due to an individual source at a screening level of 25 μSv/a, one is faced with a required lower limit of determination (LLD) of 0.1 to 0.5 Bq/kg for certain foodstuffs. In this study the potential radiological impact of foodstuffs grown in a catchment area influenced by mining and mineral processing industries in South Africa, was determined by measuring the natural radionuclides in a number of foodstuffs collected from the area. The radionuclides were measured by non-destructive techniques such as Instrumental Neutron Activation Analysis (INAA) and low background gamma spectrometry. The assessment of natural radionuclides in foods allowed us to evaluate the items that present the highest risk to the population, and compare this to the limits established by the National Nuclear Regulator (NNR). From the public’s point of view it is important to ensure the population that the contaminant levels in specific food as a result of mining activities, do not exceed the permissible limits. For the majority of the analysed foodstuffs, the estimated dose was less than 250 μSv/a. Overestimation of dose, due to poor measurement detection limits, was clearly indicated for some of the samples. For most of the analysed nuclides, suitable data for evaluation of the yearly dose at the screening level of 25 μSv/a was obtained by broad energy gamma analysis of ashed samples. However, nuclides such as 230Th, 210Po and 231Pa has to be analysed by radiochemical separation through acid destruction of dried foodstuffs followed by individual element separations to provide suitable data with a low enough LLD not to result in an overestimation of the calculated dose.
Determination of Polonium-210 in various foodstuffs after microwave digestion
- J. Barescut, I. Louw, A. Faanhof, D. Kotze
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- Journal:
- Radioprotection / Volume 44 / Issue 5 / 2009
- Published online by Cambridge University Press:
- 06 June 2009, pp. 89-95
- Print publication:
- 2009
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Natural radioactivity is associated with the vast mineral resources in South Africa in such concentrations that the radionuclides from the natural uranium and thorium decay series are found to pose concern for public exposure to communities living around these areas. The radiological impact of all operations is monitored as part of the license obligations, imposed by the South African National Nuclear Regulator Act [1]. Two main pathways giving rise to significant exposures are of interest: (a) direct ingestion resulting from regular and continuous use of contaminated water for drinking purposes, and (b) regular consumption of fish and other food products harvested from and/or grown in contaminated areas. To measure the individual nuclides in foodstuffs at the required sensitivity level in order to evaluate the yearly dose due to an individual source at a screening level of 25 μSv/a, one is faced with a required lower limit of determination (LLD) of 0.1 to 0.5 Bq/kg for certain foodstuffs. For some of the nuclides this LLD can only be obtained with radiochemical separation through acid destruction of dried foodstuffs followed by individual element separations. In this study the digestion of foodstuffs in an open-vessel microwave system followed by the determination of 210Po through radiochemical separation by spontaneous deposition onto silver discs and subsequent measurement by α-spectrometry, has been evaluated. The levels of 210Po in a variety of foodstuffs were determined and the estimated dose for the adult age group, resulting from consumption was evaluated. The dose from 210Po varied from 4 to 250 μSv/a for the various foodstuffs, with the largest intake from fish (about 0.5 Bq/day). The assessment of natural radionuclides in foods allowed us to evaluate the items that present the highest risk to the population, and compare this to the limits established by the National Nuclear Regulator (NNR). Not much data of this kind is available in South Africa. However, one would need more accurate consumption/intake values to calculate the actual yearly dose and the potential radiological impact on the public.
22 - Synthesis and pharmacological profiling of new orally active steroidal androgens
- Edited by E. Nieschlag, Westfälische Wilhelms-Universität Münster, Germany, H. M. Behre, Westfälische Wilhelms-Universität Münster, Germany
- Assisted by S. Nieschlag
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- Book:
- Testosterone
- Published online:
- 18 January 2010
- Print publication:
- 01 April 2004, pp 665-684
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Summary
Introduction
There is a general need for new orally active androgens, to be used for androgen replacement therapy and male hormonal contraception. As a substitute for low levels of testosterone in hypogonadal men, therapy with the natural androgen testosterone is the first choice. However, testosterone is an androgen with a relatively low affinity for the androgen receptor. It is metabolically relatively unstable which results in poor oral bioavailability. In addition, testosterone is converted by 5α-reductase into the more potent androgen 5α-dihydrotestosterone (5α-DHT). Early attempts to prevent metabolic instability by 17α-alkylation of androgens (like introduction of 17 α-ethynyl in estrogens and progestagens) were not successful, due to liver toxicity or low androgenic activity (Vida 1969). Another approach to circumvent metabolic instability is esterification of the 17β-OH group of testosterone with long chain fatty acids. Testosterone undecanoate formulated in an oily solution (Andriol®/Andriol TestocapsTM, dissolved in oleic acid and a mixture of castor oil and polypropylene glycol laurate, respectively) is currently the only orally active testosterone derivative. This testosterone ester is hydrolysed by tissue (liver) esterases and testosterone is released (Bursi et al. 2001). However, due to the limited potency of testosterone and limited bioavailability of testosterone undecanoate, relative high doses of Andriol®/Andriol TestocapsTM are required twice a day for human androgen replacement (total dose 160–240 mg).
Although no side effects of testosterone replacement on the prostate have been reported, androgens which are not potentiated upon 5α-reduction in the prostate and skin, like 7α-methyl-19-nortestosterone (MENT) and 19-nortestosterone (nandrolone), are considered prostate-safe androgens (Kumar et al. 1992; Cummings et al. 1998).
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