32 research outputs found

    Zinc Nutrition of Rice Plants as Influenced by Seed Germinated in Zinc Solutions

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    In recent years a physiological disorder of rice (Oryza sativa L.) seedlings growing in soils high in exchangeable calcium has been diagnosed as zinc deficiency. Calculations show that less than 30 g of zinc is needed to satisfy the nutrition of a hectare of 6-8-wk-old rice plants. Rice seed was soaked and germinated in dilute solutions of zinc ethylenediamine tetraacetate, zinc sulfate and zinc lignosulfonate prior to planting in greenhouse pots containing a zinc-deficient soil. The rice plants grown from the zinc-treated seed produced more growth and sorbed more zinc than rice plants grown from untreated seed

    In vitro Culture of Several Rice Cultivars

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    Tissue culture methods have been established to regenerate certain rice (Oryza sativa L) cultivars, but regeneration of the rice cultivars widely grown in Arkansas has not been reported. This study has established an in vitroculture for the rice cultivars \u27Nortai\u27, \u27Starbonnet\u27, \u27Mars\u27, Tebonnet\u27, \u27Newbonnet\u27, and \u27Lemont\u27. Callus was induced in the dark at either 20 or 28 C from dehusked seeds cultured on Murashige and Skoog (MS) medium (Murashige and Skoog, 1962) containing 40 g L^-1 sucrose, 10 g L^1 agar, 0.5, 1.0, or 2.0 mg L^-1 1 2,4-dichlorophenoxyacetic acid (2,4-D) and adjusted to pH 5.7. After four weeks the calli were weighed, transferred onto MS medium containing no 2,4-D, and maintained in a 1 2-h photoperiod (65 uE m^-2 s^-1) at 25 ± 2 C to induce plant regeneration. Callus production was best when cultured on a medium containing 1.0 mg L^-1 2,4-D and incubated at 28 C. Plant regeneration was observed two to four weeks later. The percentage of calli regenerating platlets varied with the cultivar and the callus induction treatment. Callus induction at 20 C on a medium with a 2,4-D level less than 2.0 mg L^-1 enhanced the regenerability of most cultivars. Regenerates were transplanted to soil and grow normally to maturity. This system can be helpful in improving rice cultivars with tissue culture techniques such as somaclonal variant selection and somatic hybridization

    Changes in Forest Soils Following Clearcutting of Pine Forests in the Ouachita Mountains of Arkansas

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    Soil characteristics of the mineral surface soil (0-6 cm) on three small watersheds in the Ouachita Mountains of Arkansas from which the pine forests have been clearcut, crushed, and burned for site preparation were studied for the first two years following clearcutting and compared to soils from adjacent uncut pine forest watersheds. Following clearcutting and burning, soil pH was generally higher than in uncut forest soils. The greatest pH differences occurred within several months of burning and generally decreased through the end of the second year. Soil organic matter content was lower immediately following clearcutting and burning and increased to levels greater than those of the uncut forest soils. Little or no differences in organic matter content were found by the end of the second year. Available soil P levels were significantly higher soon after clearcutting and burning. Available P levels decreased until there were little or no differences between the clearcut and uncut forest soils by the end of the second year. Soil inorganic nitrogen (NH₄ and NO₃ ) levels were variable but usually were greater on the clearcut sites than on the uncut sites

    Residual Effects of N-K Fertilization of Coastal Bermudagrass on Spring Populations of Weed Species

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    A Coastal bermudagrass (Cynodon dactylon L.) sod was treated during a five-year period with rates of N and K fertilizers ranging from none to high levels of both elements. In the spring of the sixth year differences in weed species and population densities among the treated plots were observed. Spring weed counts showed that high rates of N fertilizer reduced the number of weed species and the total broadleaf weed population density by 37 and 81%, respectively. The higher rates of K fertilizer also reduced the population density of common dandelion (Taraxacum officinale Weber) and yellow toadflax (Linaria vulgaris Hill),the two dominant broadleaf weed species. The grass weed population, predominantly crabgrass (Digitaria sanguinalis ,L. Scop.) was not affected significantly by either N or K fertilizer levels

    Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

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    Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

    Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

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    Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

    Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

    Get PDF
    Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome
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