GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 21 (2005), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Sodic and saline–sodic soils are characterized by the occurrence of sodium (Na+) at levels that result in poor physical properties and fertility problems, adversely affecting the growth and yield of most crops. These soils can be brought back to a highly productive state by providing a soluble source of calcium (Ca2+) to replace excess Na+ on the cation exchange complex. Many sodic and saline–sodic soils contain inherent or precipitated sources of Ca2+, typically calcite (CaCO3), at varying depths within the profile. Unlike other Ca2+ sources used in the amelioration of sodic and saline-sodic soils, calcite is not sufficiently soluble to effect the displacement of Na+ from the cation exchange complex. In recent years, phytoremediation has shown promise for the amelioration of calcareous sodic and saline–sodic soils. It also provides financial or other benefits to the farmer from the crops grown during the amelioration process. In contrast to phytoremediation of soils contaminated by heavy metals, phytoremediation of sodic and saline–sodic soils is achieved by the ability of plant roots to increase the dissolution rate of calcite, resulting in enhanced levels of Ca2+ in soil solution to replace Na+ from the cation exchange complex. Research has shown that this process is driven by the partial pressure of CO2 (PCO2) within the root zone, the generation of protons (H+) released by roots of certain plant species, and to a much smaller extent the enhanced Na+ uptake by plants and its subsequent removal from the field at harvest. Enhanced levels of PCO2 and H+ assist in increasing the dissolution rate of calcite. This results in the added benefit of improved physical properties within the root zone, enhancing the hydraulic conductivity and allowing the leaching of Na+ below the effective rooting depth. This review explores these driving forces and evaluates their relative contribution to the phytoremediation process. This will assist researchers and farm advisors in choosing appropriate crops and management practices to achieve maximum benefit during the amelioration process.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Thermochimica Acta 113 (1987), S. 1-6 
    ISSN: 0040-6031
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The evolution of the variant of coxsackievirus A 24 (CA 24 v) which causes acute hemorrhagic conjunctivitis was explored. Using 15 isolates obtained from Southeast Asia during the period 1970–1986, the genetic distance between isolates was estimated from pairwise comparison of nucleotide changes deduced from common spots on oligonucleotide maps of the isolates. From regression analysis of the genetic distance and the time of isolation of the isolates, the evolutionary rate of CA 24 v was estimated to be 3.44×10−4/nucleotide/month. The phylogenetic relationship of these isolates was explored using the neighbor-joining method and the modified unweighted pair group method using arithmetic averages (UPGMA). The phylogenetic tree constructed indicates that CA 24 v appeared from one focal place in July 1968±25 months, very close to the time of the first world epidemic of, then newly recognized, acute hemorrhagic conjunctivitis.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Environment, development and sustainability 2 (2000), S. 13-21 
    ISSN: 1573-2975
    Keywords: cadmium ; human health ; municipal sewage ; soil contamination ; vegetables
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Sociology
    Notes: Abstract Cadmium (Cd) is considered as a potential toxin that is principally dispersed in natural and agricultural environments through anthropogenic sources. Untreated municipal sewage, often a potential source of Cd, is generally used to irrigate urban agricultural soils in many developing countries. A study was carried out to determine Cd concentration in untreated municipal sewage and sewage-irrigated soils and vegetables. The metal ion concentration in municipal sewage was found 3-fold (0.03 mg L−1) its permissible concentration in irrigation water (≤0.01 mg L−1). Ammonium bicarbonate–diethylene triamine pentaacetic acid NH4HCO3–DTPA) extractable Cd concentration in top 0.15 m soil ranged between 0.25 and 0.34 mg kg−1. Soil Cd concentration was significantly correlated with soil clay content, pH, electrical conductivity, and cation exchange capacity. Cadmium availability index (CDI) decreased with an increase in soil depth. The metal ion was found in leaf (0.17–0.24 mg kg−1 fresh weight) and fruit (0.07–0.18 mg kg−1 fresh weight) portions of all the sampled vegetables: bitter gourd (Momordica charantia L.), cauliflower (Brassica oleracea L.), eggplant (Solanum melongena L.), fenugreek (Trigonella foenumgraecum L.), okra [Abelmoschus esculentus (L.) Moench], onion (Allium cepa L.), pumpkin (Cucurbita pepo L.), and spinach (Spinacia oleracea L.). Leafy tissue accumulated Cd about twice that of the fruit portion. Our results suggest that prolonged ingestion of sewage-irrigated leafy vegetables can develop such Cd levels in human body that may cause a number of illnesses.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 2905-2912 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The thermal characterization of a series of polyquinazolones, poly(quinazolone diones), and polybenzoxazinones by thermal analytical techniques (TG, DSC) is described. Comparative thermal stability measurements by dynamic and isothermal TG in air and N2 are critically discussed. Kinetic studies by isothermal TG in air and nitrogen leading to activation energies are described. The inherent difficulties in comparative thermal stability studies on complex polymer systems are discussed in terms of their structural and compositional variables and their effect on the assessment parameters used.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2013-04-11
    Description: Pseudomonas aeruginosa produces three exopolysaccharides, Psl, Pel, and alginate, that play vital roles in biofilm formation. Pel is a glucose-rich, cellulose-like exopolysaccharide. The essential Pel biosynthesis proteins are encoded by seven genes, pelA to pelG . Bioinformatics analysis suggests that PelF is a cytosolic glycosyltransferase. Here, experimental evidence was provided to support this PelF function. A UDP-glucose dehydrogenase-based assay was developed to quantify UDP-glucose. UDP-glucose was proposed as the substrate for PelF. The isogenic pelF deletion mutant accumulated 1.8 times more UDP-glucose in its cytosol than the wild type. This suggested that PelF, which was found localized in the cystosol, uses UDP-glucose as substrate. Additionally, in vitro experiments confirmed that PelF uses UDP-glucose as substrate. To analyze the functional roles of conserved residues in PelF, site-directed mutagenesis was performed. The presence of the EX 7 E motif is characteristic for various glycosyltransferase families, and in PelF, E405/E413 are the conserved residues in this motif. Replacement of E405 with A resulted in a reduction of PelF activity to 30.35% ± 3.15% (mean ± standard deviation) of the wild-type level, whereas replacement of the second E, E413, with A did not produce a significant change in the activity of PelF. Moreover, replacement of both E residues did not result in a loss of PelF function, but replacement of the conserved R325 or K330 with A resulted in a complete loss of PelF activity. Overall, our data show that PelF is a soluble glycosyltransferase that uses UDP-glucose as the substrate for Pel synthesis and that conserved residues R325 and K330 are important for the activity of PelF.
    Print ISSN: 0099-2240
    Electronic ISSN: 1098-5336
    Topics: Biology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2016-07-06
    Description: Limited frequency interval Gramians-based model reduction techniques for generalized non-singular systems are presented. These techniques generalize the results of existing limited frequency interval Gramians schemes for general non-singular systems. Numerical examples are also presented to illustrate the effectiveness of proposed techniques.
    Print ISSN: 0265-0754
    Electronic ISSN: 1471-6887
    Topics: Mathematics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...