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Shepard JF, Chu F, Xu B, Trolier-McKinstry S. The Effects of Film Thickness and Texture on the high and Low-Field stress Response of Lead Zirconate Titanate Thin Films. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-493-81] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTLead zirconate titanate (PZT) thin films are currently employed in non-volatile ferroelectric memories (FRAM's) and are intended to be used as the active material in a number of microelectromechanical systems (MEMS). Several groups have reported that both the piezoelectric and dielectric characteristics of ferroelectric thin films improve with an increase of film thickness, though the reasons for those improvements are unclear. Previous investigations on the effects of biaxial mechanical stress indicate that non-180° domain wall motion is limited in PZT 52/48 films less than 0.5 μm thick. It is possible that some of the improvements of the dielectric and piezoelectric characteristics reported for thicker films (i.e. films thicker than 0.5 μm) are associated with an increase of extrinsic contributions to the properties. To evaluate domain wall mobility in thicker films, the high and low-field stress response of sol-gel PZT fabricated with either rapid thermal processing or conventional furnace annealing were investigated. Films with thicknesses ranging from 0.6 to 5.0 μm thick were measured as a function of applied biaxial stress (±110 MPa). It was found that for all films tested the changes of capacitance were on the order of 2–3%. High-field measurements showed: (1) the coercive field to be insensitive to applied stress, (2) remanent polarizations to decrease about 20% at the maximum applied tension, (3) remanent polarizations to increase less than 10% with applied compression, and (4) all changes to be reversible over the stress range investigated. These results suggest that extrinsic contributions are limited for the films tested.
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Xu F, Chu F, Shepard JF, Trolier-McKinstry S. Measurement of Effective Longitudinal Piezoelectric Coefficient of thin Films by Direct Piezoelectric Effect. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-493-427] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThis paper presents a new method for the measurement of the longitudinal piezoelectric coefficient of piezoelectric thin films using the direct piezoelectric effect. A uniform uniaxial stress was applied to the piezoelectric thin film by high-pressure gas and the induced charge was collected and measured by a charge integrator. The effective longitudinal piezoelectric coefficient of lead zirconate titanate (PZT) 52/48 thin films made by sol-gel processing was measured by this method. Undoped films typically have d33 values of ∼ 5 pC/N, while poled films have values up to 220 pC/N.
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Abstract
Protoplasts of sexually incompatible species have been fused and in some combinations have given rise to somatic hybrid plants. Partial elimination of parental chromosomes from either species is common in such hybrids, but total chromosome loss has generally occurred only with phylogenetically unrelated pairings. Genetic function of one parent may be retained despite a complete loss of its chromosomes, suggesting that genetic introgression is possible in the absence of complete donor chromosomes. A model interspecific combination for such studies is the potato-tomato somatic hybrid for which numerous phenotypes and karyotypes are encountered at the outset, with a broader range observed in the second somatic generation.
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Abstract
Clonal populations regenerated from single-leaf cell protoplasts of the potato cultivar ;Russet Burbank' display a high frequency of variation for several horticultural and disease resistance characters. Observations over a period of three tuber generations suggest stable changes in tuber shape, yield, and maturity date, in photo-period requirements for flowering, and in plant morphology. Enhanced resistance to early blight (Alternaria solani) and late blight (Phytophthora infestans) diseases also regularly occurs within regenerated populations. These findings are discussed in the context of possible application to varietal improvement, particularly as they pertain to asexually propagated plants.
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Affiliation(s)
- J F Shepard
- Department of Psychology, University of Michigan
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Yarrow SA, Wu SC, Barsby TL, Kemble RJ, Shepard JF. The introduction of CMS mitochondria to triazine tolerant Brassica napus L., var. "Regent", by micromanipulation of individual heterokaryons. Plant Cell Rep 1986; 5:415-418. [PMID: 24248394 DOI: 10.1007/bf00269630] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/1986] [Indexed: 06/02/2023]
Abstract
Cytoplasmic triazine tolerance and cytoplasmic male sterility traits were combined in the nuclear genomic background of the Brassica napus variety 'Regent', following protoplast fusion, selection of fusion products by manual micro-manipulation, and culture in a Nicotiana tabacum nurse system. Whole plant cybrid regenerants were morphologically normal and produced seed on pollination, demonstrating their potential for incorporation into a breeding program.
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Affiliation(s)
- S A Yarrow
- Division of Plant Biology, Allelix Inc., 6850 Goreway Drive, L4V 1P1, Mississauga, Ontario, Canada
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Kemble RJ, Barsby TL, Wong RS, Shepard JF. Mitochondrial DNA rearrangements in somatic hybrids of Solanum tuberosum and Solanum brevidens. Theor Appl Genet 1986; 72:787-793. [PMID: 24248201 DOI: 10.1007/bf00266546] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/1986] [Accepted: 04/24/1986] [Indexed: 06/02/2023]
Abstract
Thirty somatic hybrids between Solanum tuberosum and Solanum brevidens were analysed for mitochondrial and chloroplast genome rearrangements. In all cases, the chloroplast genomes were inherited from one of the parental protoplast populations. No chloroplast DNA alterations were evident but a range of mitochondrial DNA alterations, from zero to extensive intra- and inter-molecular recombinations, were found. Such recombinations involved specific 'recombination hot spots' in the mitochondrial genome. Not all hybrids regenerated from a common callus possessed identical mitochondrial genomes, suggesting that sorting out of mitochondrial populations in the callus may have been incomplete at the plant regeneration stage. Sorting out of organelles in planta was not observed.
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Affiliation(s)
- R J Kemble
- Department of Plant Biology, Allelix Inc., 6850 Goreway Drive, L4V 1P1, Mississauga, Ontario, Canada
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Barsby TL, Yarrow SA, Shepard JF. A rapid and efficient alternative procedure for the regeneration of plants from hypocotyl protoplasts of Brassica napus. Plant Cell Rep 1986; 5:101-3. [PMID: 24248044 DOI: 10.1007/bf00269244] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/1986] [Revised: 01/31/1986] [Indexed: 05/05/2023]
Abstract
Protoplasts of several spring and winter varieties of Brassica napus were isolated from hypocotyl tissue. Protoplasts divided and formed cell colonies at high frequency, without browning when cultured in modified Shepards' medium. This high efficiency of proliferation was sustained through to plant regeneration with all varieties cultured. This has been attributed to the incorporation of a reservoir medium, the presence of 2,4-D in the proliferation medium, and the presence of kinetin in conjunction with lowering of the sucrose concentration in the regeneration medium.
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Affiliation(s)
- T L Barsby
- Allelix Inc., 6850 Goreway Drive, L4V 1P1, Mississauga, Ontario, Canada
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Kemble RJ, Shepard JF. Cytoplasmic DNA variation in a potato protoclonal population. Theor Appl Genet 1984; 69:211-216. [PMID: 24253714 DOI: 10.1007/bf00272897] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/1984] [Accepted: 06/27/1984] [Indexed: 06/02/2023]
Abstract
Mitochondrial DNA variation was detected in potato plants (protoclones) regenerated from leaf mesophyll protoplasts. Two forms of variation were evident; (1) DNA sequence alterations within the high molecular weight mitochondrial chromosome and (2) the appearance of an additional low molecular weight mitochondrial DNA species. Variation in chloroplast DNA was not detected. The data suggests that protocloning can introduce molecular diversity into mitochondrial genomes and thereby assist in overcoming the cytoplasmic genetic uniformity prevalent in most major crops.
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Affiliation(s)
- R J Kemble
- Department of Plant Biology, Allelix Inc., 6850 Goreway Drive, L4V 1P1, Mississauga, Ontario, Canada
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Barsby TL, Shepard JF, Kemble RJ, Wong R. Somatic hybridization in the genus Solanum: S. tuberosum and S. brevidens. Plant Cell Rep 1984; 3:165-167. [PMID: 24253478 DOI: 10.1007/bf00270215] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/1984] [Indexed: 06/02/2023]
Abstract
Somatic hybrid plants were regenerated from fused mesophyll protoplasts of an albino potato (Solanum tuberosum spp. tuberosum) variant and Solanum brevidens, a non-tuber bearing species which is sexually incompatible with S. tuberosum. These somatic hybrid plants represent the first example of direct hybridization between potato and members of the taxonomic group Etuberosa, and offer the potential for introgressing valuable germplasm from Solanum species outside the sexually compatible range into a worldwide crop species.
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Affiliation(s)
- T L Barsby
- Department of Plant Biology, Allelix Inc., 6850 Goreway Drive, L4V 1P1, Mississauga, Ontario, Canada
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Barsby TL, Yarrow SA, Shepard JF. Heterokaryon identification through simultaneous fluorescence of tetramethylrhodamine isothiocyanate and fluorescein isothiocyanate labelled protoplasts. Stain Technol 1984; 59:217-20. [PMID: 6495350 DOI: 10.3109/10520298409113859] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Protoplasts were separately stained with the fluorescent dyes fluorescein isothiocyanate (FITC) and tetramethylrhodamine isothiocyanate (TRITC). Following fusion, doubly stained heterokaryons were identified under fluorescence microscopy by using the Zeiss filter set 48 77 05 (excitation filter 450-490 nm, dichroic reflector 510 nm, and barrier filter 520 nm) which allowed simultaneous fluorochrome emissions. Previously, either emission spectrum, but not both, was possible for any single filter set.
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Abstract
Mesophyll cell protoplasts were isolated from potato (Solanum tuberosum L. cv. Russet Burbank) leaves and induced to proliferate in culture. Protoplast division was observed only among preparations isolated from plants previously conditioned under short periods of low intensity illumination. Sustained growth and development of protoplast-derived calli (p-calli) occurred when they were maintained on defined media at 24 C under 500 lux lighting. Shoot bud development within p-calli was controlled by a number of factors including light, temperature, basic medium composition, nature and source of phytohormones, the continued presence of an osmoticum, low concentrations of a utilizable carbohydrate, and the developmental stage of the p-callus.
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Affiliation(s)
- J F Shepard
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506
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Shepard JF. Regeneration of plants from prtoplasts of potato virus X-infected tobacco leaves. II. Influence of virazole on the frequency of infection. Virology 1977; 78:261-6. [PMID: 860402 DOI: 10.1016/0042-6822(77)90097-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Shepard JF, Uyemoto JK. Influence of elevated temperatures on the isolation and proliferation of mesophyll protoplasts from PVX-and PVY-infected tobacco tissue. Virology 1976; 70:558-60. [PMID: 1266052 DOI: 10.1016/0042-6822(76)90299-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Shepard JF, Totten RE. Isolation and Regeneration of Tobacco Mesophyll Cell Protoplasts under Low Osmotic Conditions. Plant Physiol 1975; 55:689-94. [PMID: 16659148 PMCID: PMC541687 DOI: 10.1104/pp.55.4.689] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A method is described for the isolation of large numbers of tobacco (Nicotiana tabacum L. cv. Xanthi-nc) mesophyll cell protoplasts under relatively low external osmotic conditions. The procedure utilized 0.2 m sucrose as the primary osmoticum and a mixture of 0.5% macerozyme, 4% cellulase, and 2% polyvinylpyrrolidone, pH 5.4. The viability of resultant protoplasts was confirmed through regeneration of fertile plants. Plating and regeneration studies revealed, however, that qualitative and quantitative modifications in plating and differentiation media were necessary for protoplasts prepared in this manner. Over-all, the procedure was found to be a simplified alternative to those previously described for tobacco protoplast regeneration. In addition, the system should permit studies related to the influence of differing osmoticum levels on a variety of cell functions.
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Affiliation(s)
- J F Shepard
- Department of Plant Pathology, Montana State University, Bozeman, Montana 59715
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Shalla TA, Shepard JF. An antigenic analysis of potato virus X and of its degraded protein. II. Evidence for a conformational change associated with the depolymerization of structural protein. Virology 1970; 42:835-47. [PMID: 4099083 DOI: 10.1016/0042-6822(70)90333-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Shepard JF, Shalla TA. An antigenic analysis of potato virus X and of its degraded protein. I. Evidence for and degree of antigenic disparity. Virology 1970; 42:825-34. [PMID: 4992355 DOI: 10.1016/0042-6822(70)90332-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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