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  • Articles  (103)
  • Chemical Engineering  (99)
  • particle bombardment  (4)
  • ASTROPHYSICS
  • Analytical Chemistry and Spectroscopy
  • Deutschland
  • 1955-1959  (103)
  • 1955  (103)
  • 1
    ISSN: 1573-5060
    Keywords: Hordeum vulgare ; isolated microspores ; particle bombardment ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A highly regenerable, isolated microspore system for barley, Hordeum vulgare L. cv. Igri, has been developed which is amenable to transformation studies using particle bombardment. The system allows DNA to be delivered to microspores at the single cell stage and both transient and stable transformation events have been demonstrated. The potential advantages of using isolated microspores as the target tissue in routine transformation systems are discussed.
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  • 2
    ISSN: 1573-5060
    Keywords: gene transfer ; Hordeum vulgare ; neomycin phosphotransferase II ; particle bombardment ; transgenic barley
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Transgenic barley plants (Hordeum vulgare L. cv. Kymppi) were obtained by particle bombardment of various tissues. Immature embryos and microspore-derived cultures were bombarded with gold particles coated with plasmid DNA carrying the gene coding for neomycin phosphotransferase II (NPTII), together with plasmid DNA containing the gene for β-glucuronidase (GUS). Bombarded immature embryos were grown to plants without selection and NPTII activity was screened in small plantlets. One plant proved to be transgenic (T0). This chimeric plant passed the transferred nptII gene to its T1 progeny. The presence of the nptII gene was demonstrated by the PCR technique and enzyme activity was analyzed by an NPTII gel assay. Four T0 spikes and 15 T1 offspring were transgenic. The integration and inheritance was confirmed by Southern blot hybridization. Transgenic T2 and T3 plants were produced by isolating embryos from green grains of transgenic T1 and T2 plants, respectively and growing them to plants. After selfing, the ratio of transgenic to non-transgenic T2 offspring was shown to follow the rule of Mendelian inheritance. The general performance of transgenic plants was normal and no reduction in fertility was observed. Microspore-derived cultures were bombarded one and four weeks after microspore isolation. After bombardment, cultures were grown either with or without antibiotic selection (geneticin R or kanamycin). When cultures were grown without selection and regenerated plants were transferred to kanamycin selection in rooting phase, one out of a total of about 1500 plants survived. This plant both carried and expressed the transferred nptII gene. The integration was confirmed by Southern blot hybridization. This plant was not fertile.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 85 (1955), S. 35-44 
    ISSN: 1573-5060
    Keywords: cereals ; protoplast transformation ; tissue electroporation ; particle bombardment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Many aspects of basic and applied problems in plant biology can be investigated by transformation techniques. In dicotyledonous species, the ability to generate transgenic plants provides the tools for an understanding of plant gene function and regulation as well as for the directed transfer of genes of agronomic interest. For many dicotyledonous plants Agrobacterium tumefaciens can be routinely used to introduce foreign DNA into their genome. However, cereals seem to be recalcitrant to Agrobacterium-mediated transformation. In cereals, many efforts have been made in recent years to establish reliable transformation techniques. Several transformation techniques have been developed but to date only three methods have been found to be suitable for obtaining transgenic cereals: transformation of totipotent protoplasts, particle bombardment of regenerable tissues and, more recently, tissue electroporation. The current state of transformation methods used for cereals will be reviewed.
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  • 4
    ISSN: 1573-5060
    Keywords: gene transfer ; crop species ; particle bombardment ; transgenic plants ; cereals ; legumes ; woody plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The limiting component in the creation of transgenic crops has been the lack of effective means to introduce foreign genes into elite germplasm. However, the development of novel direct DNA transfer methodology, by-passing limitations imposed by Agrobacterium-host specificity and cell culture constraints, has allowed the engineering of almost all major crops, including formerly recalcitrant cereals, legumes and woody species. The creation of transgenic rice, wheat, maize, barley, oat, soybean, phaseolus, peanut, poplar, spruce, cotton and others, in an efficient and in some cases, variety-independent fashion, is a significant step towards the routine application of recombinant DNA methodology to the improvement of most important agronomic crops. In this review we will focus on key elements and advantages of particle bombardment technology in order to evaluate its impact on the accelerated commercialization of products based on agricultural biotechnology and its utility in studying basic plant developmental processes and function through transgenesis. Fundamental differences between conventional gene transfer methods, utilizing Agrobacterium vectors or protoplast/suspension cultures, and particle bombardment will be discussed in depth.
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 342-348 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A correlation is presented relating the heat transfer characteristics of cross-flow heat exchangers to the void-volume-and-tube-pitch ratio. A similar correlation is found to be applicable to heat and mass transfer in packed and fluidized beds and through screens.A limited amount of data has been obtained on the effect of the Prandtl modulus at high Reynolds numbers. These data seem to indicate, as do those for flow through tubes, that the Prandtl number exponent is a function of Reynolds number.
    Additional Material: 14 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 349-354 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: According to the concept of two-phase fluidization, a part of the gas in a fluidized reactor passes through the uniform dispersed solid-gas phase in the form of bubbles, channels, and slugs. Material transport by mixing or diffusion takes place at the phase boundaries. A mass transfer coefficient between the two phases may be used to evaluate the effectiveness of contact between the gas and solid. The reaction rate for the catalytic decomposition of nitrous oxide was determined in a fluidized bed of impregnated alumina particles and compared with the corresponding rate in a fixed bed. Simultaneous rate equations were established based on the assumption that the continuous phase is either completely unmixed or uniformly mixed, and the discontinuous phase passes without mixing. The effects of the velocity of the gas, the particle size, and the bed depth on the transfer coefficient were investigated. Applications to heat transfer in fluidized beds and equipment design are discussed.
    Additional Material: 8 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 358-365 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: X-ray absorption is presented as a unique tool for the study of the fundamentals of gas fludization. For example, bed-density profiles, valuable indexes of the quality of fluidization, are readily determined by means of X-ray absorption. No internal probes, to interfere with the normal action within a fluidized bed, are involved.As an initial application of X-ray absorption to fluidization, the results of a study of the effect of mode of distribution of gas to a fluidized bed are presented. The importance of this variable, only superficially discussed in previous literature, is clearly shown by these results. Application of X-ray absorption to other chemical engineering operations is readily conceivable.
    Additional Material: 11 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 366-373 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A study was made of the terminal velocities of fall of liquid droplets in another phase liquid under stationary conditions. The studies include dimensional analysis, experimental work for collection of fall-velocity data, and photographic studies of the drop behavior. Six systems were studied for organic liquids insoluble in and heavier than water. The experimental conditions and procedure have been standardized.For any given system, as the drop size was increased the fall velocities of the droplets increased gradually, reached a maximum, and then fell off asymptotically. Two mechanisms have been postulated, (1) for the range where the fall velocities increased with an increase of drop size and (2) for the range where the fall velocities decreased with an increase of drop size, with the maximum velocity region corresponding to the transition from region 1 and 2.
    Additional Material: 15 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 374-384 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to determine the nature of the resistance controlling heat transfer between fluidized beds and surfaces in contact with them, heat transfer measurements were made on the same solid constituents with several different fluidizing gases. The heat transfer coefficients obtained with fluidized beds are found to be proportional to the square root of the thermal conductivity of the quiescent beds. This result indicates that the process controlling fluidized heat transfer may be considered to be an unsteady-state diffusion of heat into mobile elements of quiescent bed material.This picture is analyzed mathematically to yield an equation for the heat transfer coefficient h = h \documentclass{article}\pagestyle{empty}\begin{document}$ h = \sqrt {{\rm K}_{\rm m} \rho _{\rm m} cS} $\end{document} wherein the effects of the bed thermal properties are separated from the effects of the stirring factor S, which accounts for bed motion and geometry. The mass transfer analogue is also derived and shown to correlate existing mass and heat transfer data reasonably well.It is concluded that the proposed mechanism yields a satisfactory picture of the fluidized heat transfer process and may provide the beginnings of a rational approach to the correlation and prediction of fluidized heat transfer in engineering work.
    Additional Material: 16 Ill.
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  • 10
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experimental information concerning the molecular transport of the lighter hydrocarbons in the gas phase is limited. For this reason a study was made of the Maxwell diffusion coefficients of n-hexane in the gas phase of the methane-n-hexane, and propane-n-hexane systems.Maxwell diffusion coefficients were determined at steady state for pressures up to 70 lb./sq. in. at temperatures between 70° and 220° F. The effects of interfacial resistance were considered and uncertainties as to the behavior at the end of the transport path were eliminated. Coefficients were reported with partial pressure and with fugacity as the potential. Fick diffusion coefficients were calculated for each component on the assumption that the gas phase was an ideal solution.These data indicated that the Maxwell hypothesis with fugacity as the potential in an ideal solution is a fair description of the transport characteristics of the lighter hydrocarbons in the gas phase at relatively low pressures. A regular decrease in the Maxwell diffusion coefficient with an increase in the molecular weight of the stagnant component was observed.
    Additional Material: 6 Ill.
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