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  • 1995-1999  (5)
  • 1990-1994  (8)
  • 1970-1974  (1)
  • 1930-1934
  • Occupational Health and Environmental Toxicology  (6)
  • Engineering  (5)
  • maize  (3)
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Year
  • 1
    ISSN: 1573-5028
    Keywords: Cell biology ; epigenetics ; maize ; transformation ; transgenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Zea mays transformants produced by particle bombardment of embryogenic suspension culture cells of the genotype A188 × B73 and selected on kanamycin or bialaphos were characterized with respect to transgene integration, expression, and inheritance. Selection on bialaphos, mediated by thebar orpat genes, was more efficient than selection on kanamycin, mediated by thenptII gene. Most transformants contained multicopy, single locus, transgene insertion events. A transgene expression cassette was more likely to be rearranged if expression of that gene was not selected for during callus growth. Not all plants regenerated from calli representing single transformation events expressed the transgenes, and a non-selectable gene (uidA) was expressed in fewer plants than was the selectable transgene. Mendelian inheritance of transgenes consistent with transgene insertion at a single locus was observed for approximately two thirds of the transformants assessed. Transgene expression was typically, but not always, predictable in progeny plants-transgene silencing, as well as poor transgene transmission to progeny, was observed in some plant lines in which the parent plants had expressed the transgene.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-9368
    Keywords: Agrobacterium tumefaciens ; maize ; GUS ; gusA/intron ; particle bombardment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To develop a system forAgrobacterium-mediated transformation of maize (Zea mays L.), we have investigated histochemically the transient expression of β-glucuronidase (GUS) activity in maize seedling tissue segments using binary vectors that allow minimal (pKIWI105 and pCNL1) or undetectable (p35S-GUS-INT and pCNL56) levels of GUS activity inA. tumefaciens. Tissue segments from three- to five-day-old sterile seedlings of maize genotype A188 were inoculated withA. tumefaciens. Four days after inoculation, transient expression of GUS activity was found in mesocotyl segments originating from the intercalary meristem region. This GUS activity was specific to the vascular cylinder and was not found in the internal cortical or epidermal layers, nor was it found in mature mesocotyl tissue (segments 5 mm below the coleoptilar node). Transient GUS activity was also detected in leaf and coleoptile tissues of shoot segments, but not in the shoot apexper se or in leaves younger than the first leaf. Maize tissues inoculated withA. tumefaciens strains that harbourgusA-containing binary vectors but no Ti-plasmid did not show GUS activity, supporting evidence from previous work thatvir gene activity was essential for the observed GUS activity.A. tumefaciens strains containing different types of Ti-plasmids were also tested. A strain harbouring an agropine-type Ti-plasmid was the most effective for expressing GUS activity in mesocotyl segments, whereas a strain harboring a nopaline-type Ti-plasmid was most effective for expression of GUS activity in the apical meristem-containing segment. These results indicate that different interactions occurred between the differentA. tumefaciens strains and the susceptible plant tissues. Maize genotype specificity for GUS activity in mesocotyl tissues was observed; variations in the cocultivation medium had a profound effect on the frequency of expression of GUS activity.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-1561
    Keywords: European corn borer ; Ostrinia nubilalis (Hübner) ; growth ; development ; fecundity ; oviposition ; behavior ; eggs ; DIMBOA ; water extract ; plant extract ; maize ; Peruvian maize ; maize accessions ; host plant resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Twelve Peruvian maize, Zea mays, accessions were selected because of their relatively high level of field resistance to first-generation European corn borer (ECB), Ostrinia nubilalis, larval leaf-feeding. Water extracts of freeze-dried, powdered, leaf tissue were incorporated into a standard ECB diet, fed to larvae, and the effects on larval growth, development, and fecundity were measured. Larval and pupal weights were monitored as were the time elapsed in the larval, pupal, and adult stages. Adult fecundity and egg fertility were recorded. The experiment was a randomized block design (larvae and pupae) or a completely randomized design (adults) and analyzed with ANOVA (α = 0.05). Pairwise comparisons were made between groups of insects grown on diets containing extracts from the Peruvian lines, a standard diet, or diets containing extracts of a known susceptible inbred, and a known resistant inbred line. Survival was analyzed with a chi-squared test (α = 0.05). Two Peruvian accessions significantly reduced female larval and pupal weights, extended pupal and adult development time, and decreased survival of pupae and adults. Water extracts also had a pronounced impact on males; two accessions significantly reduced pupal weight and extended the time required to pupate, and one reduced male survival to adults. The results indicate that water-soluble factors from resistant Peruvian accessions inhibit the growth, developmental time, and survival of ECB. These resistance factors could be useful in the development of maize germplasm with insect-resistant traits.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 8 (1974), S. 679-696 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The object of this paper is to describe a new algorithm for the semi-automatic triangulation of arbitrary, multiply connected planar domains. The strategy is based upon a modification of a finite element mesh genration algorithm recently developed. 1 The scheme is designed for maximum flexibility and is capable of generating meshes of triangular elements for the decomposition of virtually any multiply connected planar domain. Moreover, the desired density of elements in various regions of the problem domain is specified by the user, thus allowing him to obtain a mesh decomposition appropriate to the physical loading and/or boundary conditions of the particular problem at hand. Several examples are presented to illustrate the applicability of the algorithm. An extension of the algorithm to the triangulation of shell structures is indicated.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 17 (1996), S. 1-2 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 14 (1993), S. 503-520 
    ISSN: 0197-8462
    Keywords: constant temperature ; intracellular recording ; time series ; regression analysis ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The effects of pulsed microwaves (2.45 GHz, 10 μs, 100 pps, SAR: 81.5 kW/kg peak, 81.5 W/kg average) on membrane input resistance and action potential (AP) interval statistics were studied in spontaneously active ganglion neurons of land snails (Helix aspersa), at strictly constant temperature (20.8±.07°C worst case). Statistical comparison with sham-irradiated neurons revealed a significant increase in the mean input resistance of neurons exposed to pulsed microwaves (P ≪ .05 ). Pulsed microwaves had no visible effect on mean AP firing rate; this observation was confirmed by analysis of interspike intervals (ISIs). Using an integrator model for spontaneously active neurons, we found the net input current to be more variable in neurons exposed to pulsed microwaves. The mean input current was not affected. The standard deviation of ISIs and the autocorrelation of the input current were marginally affected, but these changes were not consistent across neurons. Although the observed effects were less obvious than those reported in other studies, they represent evidence of a direct interaction between neurons and pulsed microwaves, in the absence of macroscopic temperature changes. The data do not suggest a single, specific mechanism for such interaction. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 97-105 
    ISSN: 0197-8462
    Keywords: atrioventricular block ; heat coagulation ; reversible and irreversible block ; catheter antenna ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The use of microwave energy for ablation of the atrioventricular (AV) junction was examined in open-chest dogs. Using a specially designed microwave catheter and a 2450 MHz generator, microwave energy was delivered to the AV junction according to one of two protocols. In protocol 1, increasing amounts of energy were delivered until irreversible AV block occurred. In protocol 2, only two applications of energy were used, one at low energy and the other at an energy found to be high enough to cause irreversible AV block. Each dog received between one and six applications of microwave energy. The amount of energy delivered per application ranged from 25.6 to 311.4 J. No AV block was seen at 59.4 ± 28.3 J. Reversible AV block was seen with an energy of 120.6 ± 58 J. Irreversible AV block was seen at 188.1 ± 75.9 J. Irreversible AV block could be achieved in each animal. There was no difference in the energy required to cause irreversible AV block between the two protocols. The tissue temperature measured near the tip of the microwave catheter was correlated with both the amount of energy delivered and the extent of AV block caused. Histologic examination demonstrated coagulation necrosis of the conduction system. Microwave energy is a feasible alternative energy source for myocardial ablation. Since tissue damage is due exclusively to heating and the resulting rise in temperature can be measured, microwave energy may have advantages over currently existing energy sources in terms of both titrating delivered energy and monitoring the extent of tissue destruction. © 1995 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 42 (1998), S. 1215-1229 
    ISSN: 0029-5981
    Keywords: boundary element method ; fast multipole method ; many-particle problem ; linear elasticity ; iterative solution strategy ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A boundary element method for solving three-dimensional linear elasticity problems that involve a large number of particles embedded in a binder is introduced. The proposed method relies on an iterative solution strategy in which matrix-vector multiplication is performed with the fast multipole method. As a result the method is capable of solving problems with N unknowns using only O(N) memory and O(N) operations. Results are given for problems with hundreds of particles in which N=O(105). © 1998 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 36 (1993), S. 1967-1986 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A state-space model for representing the non-linear material deformation and an optimal control scheme for obtaining desired process conditions in the deforming material are presented in this paper. The formulation is general for various metal-forming processes including forging and extrusion operations. The state variables selected in the formulation are the die/billet contact nodal velocities and the nodal velocities of the critical finite elements of the billet. The control input is the ram velocity, which is determined by using the linear quadratic regulator (LQR) theory to maintain desired strain rates within the selected finite elements. The influence of an optimally designed ram velocity on the deforming material is studied using performance measures. This paper includes the development of the state-space model from non-linear finite element formulation, optimal control strategy and numerical example cases with discussions.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 37 (1994), S. 155-177 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper presents a state space model and an optimal design scheme for non-isothermal metal forming processes. By selecting nodal velocity and temperature as the state variables, a non-isothermal state equation with coupled deformation and thermal terms is established. Based on this state space model, a control design scheme is developed to obtain the optimal die velocity and initial die temperature which will ensure that the effective strain-rate and temperature satisfy the design requirements. A titanium alloy engine disk forging is used to demonstrate two design examples. The results show that the proposed model and design scheme behave well for different design requirements.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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