Characterizing Groundwater Dynamics Based on Impact of Pulp and Paper Mill Effluent Irrigation and Climate Variability     

Shahbaz Khan  Muhammad Nadeem Asghar  Tariq Rana 《Water, air, and soil pollution》2007,182(1-4):131-148

Automated synoptic weather typing and robust orthogonal stepwise regression analysis (via principal components analysis) were applied together to develop within-weather-type air pollution prediction models for a variety of pollutants (specifically, carbon monoxide – CO, nitrogen dioxide – NO₂, ozone – O₃, sulphur dioxide – SO₂, and suspended particles – SP) for the period 1974–2000 in south-central Canada. The SAS robust regression procedure was used to limit the influence of outliers on air pollution prediction algorithms. Six-hourly Environment Canada surface observed meteorological data and 6-hourly US National Centers for Environmental Prediction (NCEP) reanalysis data of various weather elements were used in the analysis. The models were developed using two-thirds of the total years for meteorological and air pollution data; the remaining one-third (randomly selected) was used for model validation. Robust stepwise regression analysis was performed to analytically determine the meteorological variables that might be used to predict air pollution concentrations. There was a significant correlation between observed daily mean air pollution concentrations and model predictions. About 20, 50, and 80% of the 80 prediction models across the study area possessed R ² values ≥ 0.7, 0.6, and 0.5, respectively. The results of model validation were similar to those of model development, with slightly smaller model R ² values.  相似文献   

Boron fertilization improves seed yield and harvest index of Camelina sativa L. by affecting source-sink     

Shahbaz Khan  Hafeez ur Rehman  Muhammad Ashfaq Wahid  Muhammad Farrukh Saleem  Mumtaz Akhtar Cheema  Shahzad Maqsood Ahmed Basra 《Journal of plant nutrition》2016,39(12):1681-1687

The impact of soil (1, 2 kg ha^?1) and foliar (100, 200 mg L^?1) boron (B) with control (no B) was evaluated on phenology and yield formation of Camelina each applied at stem elongation and flowering stages. Foliar (200 mg L^?1) or soil B (2 kg ha^?1) resulted in earlier flowering and maturity, increased fruit bearing branches (19.68%), number of siliqua, seeds per siliqua (4.6%), biological yield (15%), seed yield (24%), harvest index (11.4%) and oil contents (23%) than no B. Increased fruit bearing branches, seed filled siliqua or seed numbers, harvest index and oil quality can be attributed to changes in dry matter accumulated of stem with simultaneous increase in siliqua dry weight with foliar or soil applied B. In crux, foliar (200 mg L^?1) or soil applied (2 kg ha^?1) B seems promising to improve seed and oil yield, harvest index of Camelina sativa under B deficient condition.  相似文献   

Differences Among Rice Cultivars in their Adaptation to Low Ionic Strength Solution with Toxic Level of Aluminum that Mimics Tropical Acid Soil Conditions     

M. Shahadat Hossain Khan  Tadao Wagatsuma  Afrin Akhter  Idupulapati M. Rao 《Journal of plant nutrition》2015,38(13):1973-1983

Nutrient deficiencies are often an additional growth-limiting factor in tropical acid soils. Considering the potential interactions between Al stress and low-nutrient stress, differences among rice cultivars for Al tolerance, low-nutrient tolerance, and combined stress tolerance were investigated. The main objective of this study was to identify the predominant growth-limiting factor in tropical acid soils. Tolerance to low nutrient stress and combined stress did not show any relationship with aluminum (Al) tolerance indicating that these stress factors act independently. Al-tolerant cv. Rikuu-132 was tolerant to combined stress. Conversely, highly Al-sensitive cv. BR34 was most tolerant to combined and low nutrient stress. Combined stress tolerance of shoot was positively correlated with calcium (Ca) content of shoot. The results indicate that Al tolerance alone is not adequate for superior performance on most acid soils. Tolerance to combined stress factors would be needed to improve productivity of rice on low fertility acid soils.  相似文献   

Activation of the Ah receptor by extracts of dietary herbal supplements,vegetables, and fruits     

Jeuken A  Keser BJ  Khan E  Brouwer A  Koeman J  Denison MS 《Journal of agricultural and food chemistry》2003,51(18):5478-5487

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Interaction of Metallic Cations with the Humic Acids Extracted from a Solonetz-Solod-Black Soil Sequenze in Alberta     

S. U. Khan 《植物养料与土壤学杂志》1970,127(2):121-126

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Genetic mapping in Lilium: mapping of major genes and quantitative trait loci for several ornamental traits and disease resistances     

Arwa Shahin  Paul Arens  Adriaan W. Van Heusden  Gerard Van Der Linden  Martijn Van Kaauwen  Nadeem Khan  Henk J. Schouten  W. Eric Van De Weg  Richard G. F. Visser  Jaap M. Van Tuyl 《Plant Breeding》2011,130(3):372-382

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Cytokinins: permissive role in seed germination   总被引：14，自引：0，他引：14  

A A Khan 《Science (New York, N.Y.)》1971,171(974):853-859

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Two-dimensional nanosheets produced by liquid exfoliation of layered materials   总被引：1，自引：0，他引：1  

Coleman JN  Lotya M  O'Neill A  Bergin SD  King PJ  Khan U  Young K  Gaucher A  De S  Smith RJ  Shvets IV  Arora SK  Stanton G  Kim HY  Lee K  Kim GT  Duesberg GS  Hallam T  Boland JJ  Wang JJ  Donegan JF  Grunlan JC  Moriarty G  Shmeliov A  Nicholls RJ  Perkins JM  Grieveson EM  Theuwissen K  McComb DW  Nellist PD  Nicolosi V 《Science (New York, N.Y.)》2011,331(6017):568-571

If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS(2) and MoS(2) effectively reinforce polymers, whereas WS(2)/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties.  相似文献   

Antiarthritic gold compounds effectively quench electronically excited singlet oxygen   总被引：5，自引：0，他引：5  

E J Corey  M M Mehrotra  A U Khan 《Science (New York, N.Y.)》1987,236(4797):68-69

Although certain gold [Au(I)] compounds have been used effectively in the treatment of rheumatoid arthritis for some years, the molecular basis for such therapeutic action has been unclear. One possible mechanism of the action of Au(I) compounds is that they protect unsaturated membrane lipids and proteins against oxidative degradation caused by activated phagocytes that are not properly regulated. In this study it has been shown that superoxide ion (O-2.), a product of activated phagocytes, can be oxidized to electronically excited singlet oxygen (O1(2)delta g), an agent that is capable of peroxidation of unsaturated fatty acid derivatives. It has also been shown that antiarthritic Au(I) compounds are effective deactivators of O1(2)delta g with quenching constants on the order of 10(7) M-1 sec-1.  相似文献   

Human muscle phosphoglycerate mutase deficiency: newly discovered metabolic myopathy   总被引：7，自引：0，他引：7  

S DiMauro  A F Miranda  S Khan  K Gitlin  R Friedman 《Science (New York, N.Y.)》1981,212(4500):1277-1279

Muscle phosphoglycerate mutase activity was decreased (5.7 percent of the lowest control value) in a 52-year-old man with intolerance for strenuous exercise and recurrent pigmenturia since adolescence. All of the other enzymes of glycolysis had normal activities, and glycogen concentration was normal. Electrophoretic, heat lability, and mercury inhibition studies showed that the small residual activity in the patient's muscle was represented by the brain (BB) isoenzyme of phosphoglycerate mutase, suggesting a genetic defect of the M subunit which predominates in normal muscle. The prevalence of the BB isoenzyme in other tissues, including muscle culture, may explain why symptoms were confined to muscle.  相似文献