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排序方式: 共有735条查询结果,搜索用时 31 毫秒
51.
Dagobiet Morales-Garcia Katrine A. StewartPhilippe Seguin Chandra Madramootoo 《Agricultural Water Management》2011,98(5):893-898
The effect of supplemental saline (2.5 dS m−1) drip irrigation and black polyethylene mulch on two cultivars of bell peppers (Capsicum annuum L.) was investigated under field conditions using a randomized complete block design with split-split plot restriction. The research included six irrigation treatments (main plots): (i) non-saline irrigation control applied throughout growth (None), (ii) saline irrigation from transplanting until formation of the first fruit set (S1S2), (iii) saline irrigation from transplanting until appearance of the first flower and from first harvest to final harvest (S1S4), (iv) saline irrigation from appearance of the first flower to first harvest (S2S3), (v) saline irrigation from fruit set to final harvest (S3S4), and (vi) saline irrigation throughout growth (All); two mulch treatments (subplots): (i) black mulch and (ii) bare soil; and two bell pepper cultivars (sub-subplots): (i) Early Sunsation and (ii) Red Knight. Production of fully ripened fruits was higher in mulched plants regardless of saline irrigation treatments. In humid areas with non-saline soil, supplemental saline drip irrigation could be used with black polyethylene mulch to save water while maintaining fruit production. 相似文献
52.
McPherson JP Lemmers B Chahwan R Pamidi A Migon E Matysiak-Zablocki E Moynahan ME Essers J Hanada K Poonepalli A Sanchez-Sweatman O Khokha R Kanaar R Jasin M Hande MP Hakem R 《Science (New York, N.Y.)》2004,304(5678):1822-1826
Mus81-Eme1 endonuclease has been implicated in the rescue of stalled replication forks and the resolution of meiotic recombination intermediates in yeast. We used gene targeting to study the physiological requirements of Mus81 in mammals. Mus81-/- mice are viable and fertile, which indicates that mammalian Mus81 is not essential for recombination processes associated with meiosis. Mus81-deficient mice and cells were hypersensitive to the DNA cross-linking agent mitomycin C but not to gamma-irradiation. Remarkably, both homozygous Mus81-/- and heterozygous Mus81+/- mice exhibited a similar susceptibility to spontaneous chromosomal damage and a profound and equivalent predisposition to lymphomas and other cancers. These studies demonstrate a critical role for the proper biallelic expression of the mammalian Mus81 in the maintenance of genomic integrity and tumor suppression. 相似文献
53.
Tumor suppression with a combination of alpha-difluoromethyl ornithine and interferon 总被引:1,自引:0,他引:1
alpha-Difluoromethyl ornithine and mouse type 1 interferon, when administered simultaneously, were highly toxic to B16 melanoma cells in culture. Oral administration of alpha-difluoromethyl ornithine suppressed B16 melanoma development in mice 85 percent whereas interferon given subcutaneously inhibited tumor growth only 24 percent. Total or near total suppression of tumor growth was observed in mice receiving both treatments. 相似文献
54.
We demonstrate universal computation in an all-fluidic two-phase microfluidic system. Nonlinearity is introduced into an otherwise linear, reversible, low-Reynolds number flow via bubble-to-bubble hydrodynamic interactions. A bubble traveling in a channel represents a bit, providing us with the capability to simultaneously transport materials and perform logical control operations. We demonstrate bubble logic AND/OR/NOT gates, a toggle flip-flop, a ripple counter, timing restoration, a ring oscillator, and an electro-bubble modulator. These show the nonlinearity, gain, bistability, synchronization, cascadability, feedback, and programmability required for scalable universal computation. With increasing complexity in large-scale microfluidic processors, bubble logic provides an on-chip process control mechanism integrating chemistry and computation. 相似文献
55.
Neutron stars are some of the densest manifestations of massive objects in the universe. They are ideal astrophysical laboratories for testing theories of dense matter physics and provide connections among nuclear physics, particle physics, and astrophysics. Neutron stars may exhibit conditions and phenomena not observed elsewhere, such as hyperon-dominated matter, deconfined quark matter, superfluidity and superconductivity with critical temperatures near 10(10) kelvin, opaqueness to neutrinos, and magnetic fields in excess of 10(13) Gauss. Here, we describe the formation, structure, internal composition, and evolution of neutron stars. Observations that include studies of pulsars in binary systems, thermal emission from isolated neutron stars, glitches from pulsars, and quasi-periodic oscillations from accreting neutron stars provide information about neutron star masses, radii, temperatures, ages, and internal compositions. 相似文献
56.
Mary Elizabeth K. Gnanambal K. C. Ramya Devi P. Hareesh Chandra Edward J. K. Patterson 《Phytoparasitica》2011,39(2):121-127
The current study is based on the screening of novel insecticides from new sources that have not being exploited hitherto.
The major objectives of this research work were to extract marine molluscs, Lambis lambis, Trochus radiatus and Chicoreus ramosus, from Tuticorin coastal waters using different solvents to test their insecticidal properties and partially purify the active
components. The ethyl acetate extracts of L. lambis and T. radiatus showed 100% mortality of Sitophilus oryzae, at a concentration of 200 μg ml−1. The LC50 values for ethyl acetate extracts of L. lambis, T. radiatus and C. ramosus were found to be 67.08, 348.86 and 571.42 μg ml−1, respectively. With regard to bacterial metabolites, at a concentration of 200 μg ml−1 the ethyl acetate extract of A3 was able to elicit an activity of 40% and that of strain A1 – 20%. The LC50 values of the bacterial metabolites were also investigated. Upon chromatographic separation of active ethyl acetate extracts
of T. radiatus, the 100% methanol column-purified fraction was found to have an activity of 30% at a concentration of 10 μg against S. oryzae. The purity of the partially pure active compound was observed to be 72.78% on analysis with high pressure thin layer chromatography. 相似文献
57.
S. Kundu Ranjan Bhattacharyya Ved Prakash B.N. Ghosh H.S. Gupta 《Soil & Tillage Research》2007,92(1-2):87-95
Soil organic matter (SOM) contributes to the productivity and physical properties of soils. Although crop productivity is sustained mainly through the application of organic manure in the Indian Himalayas, no information is available on the effects of long-term manure addition along with mineral fertilizers on C sequestration and the contribution of total C input towards soil organic C (SOC) storage. We analyzed results of a long-term experiment, initiated in 1973 on a sandy loam soil under rainfed conditions to determine the influence of different combinations of NPK fertilizer and fertilizer + farmyard manure (FYM) at 10 Mg ha−1 on SOC content and its changes in the 0–45 cm soil depth. Concentration of SOC increased 40 and 70% in the NPK + FYM-treated plots as compared to NPK (43.1 Mg C ha−1) and unfertilized control plots (35.5 Mg C ha−1), respectively. Average annual contribution of C input from soybean (Glycine max (L.) Merr.) was 29% and that from wheat (Triticum aestivum L. Emend. Flori and Paol) was 24% of the harvestable above-ground biomass yield. Annual gross C input and annual rate of total SOC enrichment were 4852 and 900 kg C ha−1, respectively, for the plots under NPK + FYM. It was estimated that 19% of the gross C input contributed towards the increase in SOC content. C loss from native SOM during 30 years averaged 61 kg C ha−1 yr−1. The estimated quantity of biomass C required to maintain equilibrium SOM content was 321 kg ha−1 yr−1. The total annual C input by the soybean–wheat rotation in the plots under unfertilized control was 890 kg ha−1 yr−1. Thus, increase in SOC concentration under long-term (30 years) rainfed soybean–wheat cropping was due to the fact that annual C input by the system was higher than the required amount to maintaining equilibrium SOM content. 相似文献
58.
Naturally derived micelles for rapid in vitro screening of potential cholesterol-lowering bioactives
Kirana C Rogers PF Bennett LE Abeywardena MY Patten GS 《Journal of agricultural and food chemistry》2005,53(11):4623-4627
A high plasma cholesterol level, especially low-density lipoprotein cholesterol, indicates increased risk of cardiovascular diseases. Plasma cholesterol levels are influenced by diet and cholesterol biosynthesis, uptake, and secretion. Cholesterol uptake involves solubilization into complex phospholipid spherical bodies termed micelles that facilitate the transport of lipids through the gut brush border membrane into enterocytes. In vitro assays reported to date to determine potential cholesterol-lowering effects of various compounds require artificial micelle preparations that are elaborate and time-consuming to prepare. The aims of this study were to compare the efficacy of artificially prepared micelles with naturally derived micelles from pig's bile and to test their ability to assess potential inhibitors of cholesterol uptake. The suitability of pig's bile-derived micelles was tested both at the level of the micelle and at cellular uptake using cultured Caco-2 cells. Known cholesterol uptake inhibitors at the micelle (green tea catechins) and at the Caco-2 cell (beta-lactoglobulin-derived peptide, IIAEK) were used as reference inhibitory compounds. It was concluded that pig's bile was a rapid, reproducible, convenient, and cost-effective source of micelles for cholesterol micelle solubility and cellular uptake assay systems and is suitable for screening purposes focused on identifying potential cholesterol-lowering agents. 相似文献
59.
S. K. Gupta Anamika Tewari Richa Srivastava R. C. Murthy Saurabh Chandra 《Water, air, and soil pollution》2005,163(1-4):293-302
Vermicomposting of fly ash has been attempted, using red earthworm, Eisenia foetida. Fly ash, which was obtained from thermal power station, was mixed with cowdung in different proportions (20, 40, 60 and 80%). These mixtures were used as feed for earthworms, and after 30 days, vermicast recovery, worm zoomass and numbers of juveniles produced were recorded. A total of six runs each of 30 days were conducted during the whole study. Concentrations of heavy metals in different mixtures of fly ash–cowdung, before and after vermicomposting and in the earthworms used in the study were also estimated. Results show maximum output of vermicasts and maximum number of juveniles produced was in reactors with 40% fly ash while maximum weight gain by earthworm was in 20% fly ash vermireactors. Performance of vermireactors up to 60% fly ash was more or less similar but at 80% fly ash, there is a marked reduction in overall performance of the reactors. Chemical analysis of different samples of fly ash–cowdung mixtures prior to vermicomposting revealed high concentrations of zinc, chromium, lead, nickel and copper. Chemical analysis of vermicomposted samples showed 30–50% reduction in heavy metals up to 60% fly ash and 10–30% reduction in 80% fly ash. Metal analysis of earthworms revealed considerable bioaccumulation of heavy metals in their body. The Present study indicates the feasibility of E. foetida for mitigating the toxicity of metals and up to 60% fly ash–cowdung mixtures can be used for sustainable and efficient vermicomposting. 相似文献
60.
Characterization, quantification, and bioactivities of anthocyanins in Cornus species 总被引:3,自引:0,他引:3
Seeram NP Schutzki R Chandra A Nair MG 《Journal of agricultural and food chemistry》2002,50(9):2519-2523
Cornus mas, Cornus officinalis, Cornus controversa, and Cornus kousa (Cornaceae) bear edible fruits that are consumed in parts of Europe and Asia. This study undertook the investigation of the presence and levels of anthocyanins in the fruits of these Cornus species by HPLC. The anthocyanins present in Cornelian cherries, C. mas, are delphinidin 3-O-beta-galactopyranoside (1), cyanidin 3-O-beta-galactopyranoside (2), and pelargonidin 3-O-beta-galactopyranoside (3). C. officinalis contains only anthocyanins 1-3, similar to C. mas, but in different proportions. However, C. controversa contains anthocyanins 1-3 among other anthocyanins, but Chinese dogwood, C. kousa, did not contain 1-3. The contents of pure anthocyanins 1, 2, and 3 in 1 kg of fresh fruits of C. mas, C. officinalis, and C. controversa were 280, 1079, and 710 ppm; 11, 77, and 230 ppm; and 600, 1000, and 700 ppm, respectively. In cyclooxygenase (COX)-I and -II enzyme inhibitory assays, anthocyanins 1-3 (all 40 microM) showed activities of 9.2 and 11.7%; 7.6 and 12.4%; and 5.3 and 7.8%, respectively, compared to Naproxen (54.3 and 41.3%; 10 microM), ibuprofen (47.5 and 39.8%; 10 microM), Celebrex (46.2 and 66.3%; 1.67 ppm), and Vioxx (23.8 and 88.1%, 1.67 ppm). In the antioxidant assay, anthocyanins 1-3 (all 40 microM) showed activities of 70.2, 60.1, and 40.3%, respectively. At 10 microM concentration, commercial synthetic antioxidants tert-butylhydroquinone, butylated hydroxytoluene, butylated hydroxyanisole, and vitamin E gave 83.2, 79.7, 82.1, and 10.2% of antioxidant activity, respectively. 相似文献