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  • 11
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Antibodies raised against a peptide fragment (residues 60–456) of potato sucrose phosphate synthase (SPS) were used to investigate whether potato plants contain multiple forms of SPS. When a partially purified preparation of SPS from cold-stored potato tubers was separated on 5% polyacrylamide gel electrophoresis (PAGE), four immunopositive bands were found with estimated molecular weights of 125, 127, 135 and 145 kDa. These bands were also found in rapidly prepared extracts and were termed SPS-1a, SPS-1b, SPS-2 and SPS-3, respectively. Direct evidence that SPS-1a and SPS-1b represent active SPS was provided by the finding that both are greatly reduced in plants expressing an antisense sequence derived from the potato leaf SPS gene. SPS-2 was not decreased in the antisense plants, indicating that it has a significantly different sequence. Evidence that SPS-2 represents active SPS was obtained by showing that the amount of SPS-1a and SPS-1b protein remaining in the leaves and tubers of antisense potato plants was too low to account for the remaining SPS activity. The four immunopositive SPS forms had different tissue distributions. SPS-1a was the major form in all tissues except petals, sepals and stamens. SPS-1b and SPS-2 were absent in very young growing tissues but were present as minor forms in source leaves and sprouting tubers. The SPS-1b level was especially high in petals and sepals, and the SPS-2 level was especially high in the stamens. SPS-3 was only detected in very young tissues. The four forms also showed different responses to low temperature. Transfer of tubers to 4°C led to a specific and reversible increase of SPS-1b during the next 4 d. The appearance of SPS-1b correlated with a change in the kinetic properties of SPS that has recently been shown (Hill et al. 1996) to play a key role in triggering the accumulation of sugars in cold-stored tubers. The appearance of SPS-1b protein at low temperature was accompanied by an increase of SPS transcript. Incubation of tuber slices with calyculin A and okadaic acid to alter the phosphorylation state of SPS did not lead to appearance or disappearance of SPS-1b. It is concluded that potato plants contain several forms of SPS that have different functions in growing and mature tissues, in flower parts, and in acclimation to low temperature.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Microelectronic Engineering 17 (1992), S. 555-558 
    ISSN: 0167-9317
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1572-8145
    Keywords: Sheet metal parts ; computer-aided process planning ; bending tools ; laminated object modelling ; neural networks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The manufacturing of complex bent parts can be supported effectively by computer-aided planning methods. Software systems are already available for unfolding, laser cutting and bending sequence determination. The paper focuses on methods that support the design of non-standard bending tools and the flexible manufacturing of such tools using laminated object modelling (LOM) technology. The developed system allows for concurrent planning and manufacturing of bending parts and tools. Within the framework of this system, neural networks are applied for automated tool design.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 27 (1995), S. 1257-1271 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The fundamentals of the manufacturing process of laser beam cutting are discussed. The equipment necessary for working on two- and three-dimensional applications is described. Criteria for characterizing cutting quality and cutting applications with different laser types are presented. Both modelling of the process and study of process emissions are involved in optimizing the process and system performance, and an overview is given of research results in these areas.
    Type of Medium: Electronic Resource
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  • 16
    Publication Date: 2009-10-29
    Description: Proven Infracambrian hydrocarbon plays occur in various parts of the world, including Oman, the former Soviet Union, India, Pakistan and Australia. Organic-rich strata also occur in NW Africa, and gas shows originating from Infracambrian hydrocarbon source rocks are known from well Abolag-1 in the Mauritanian part of the Taoudenni Basin. The distribution of Infracambrian source rocks in North Africa is patchy and deposition commonly occurred in half-graben and pull-apart basins. In these intra-shelf basins, marine, organic-rich shales and limestones were deposited beneath the turbulent wave zone, away from the coarse siliciclastic Pan-African molasse detritus. On the West African Craton (including the Taoudenni Basin) organic-rich horizons were also deposited earlier, in pre- and syn-Pan-African times between 0.5 and 2 Ga (Ga is 109 years). The long-lasting sedimentation history in this area contrasts with that of the Pan-African regions, such as Oman, which lies in the Pan-African province of the East African Orogen, where preserved sediments are rarely older than 640 Ma. Infracambrian black phyllites in the Anti-Atlas region of Morocco were deposited on a continental slope of a short-lived ocean lying to the north of the West African Craton. Hydrocarbons generated during Infracambrian times from these deposits, however, have a low preservation potential. Infracambrian organic-rich and/or black-pyritic deposits in North Africa are proven in the Taoudenni Basin, the Anti-Atlas and the Ahnet Basin. Thick carbonate successions exist in the Taoudenni Basin, indicating deposition in areas some distance from contaminating coarse siliciclastic hinterland influx. Infracambrian strata may also occur in the Tindouf Basin. However, their deep burial and consequent early maturation history may be unfavourable for the preservation of Infracambrian-sourced hydrocarbons in this area. Local development of Infracambrian source facies may also occur in the Reggane, Ahnet, Mouydir and Iullemeden basins, as indicated by black shales in wells MKRN-1 and MKRS-1 in the Ahnet Basin. Generally, however, these basins appear to be close to the active Pan-African orogenic belt and, consequently, probably received large quantities of coarse siliciclastic sediment, largely of continental facies, which may have diluted any significant hydrocarbon source potential.
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  • 17
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 72 (1998), S. 1323-1325 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a systematic analysis of the hole transport over heterobarriers in the InGaAs(P)/InP material system. The experiments have been performed on our recently developed all-optical switching structures [C. Knorr et al., Appl. Phys. Lett. 69, 4212 (1996)], which offer an elegant access to hole transport rates. We have varied barrier thickness, barrier height, bias voltage, and temperature. The time constants vary from 30 μs to 30 ns. Our model calculations, including all heavy and light hole subbands, show that only thermally assisted tunneling can explain both the temperature and electric field dependence of the transport rates. We have extracted the activation energies. The hole capture time is determined as 250±50 fs. © 1998 American Institute of Physics.
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  • 18
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 54 (1932), S. 3064-3070 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 2127-2129 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Spontaneously ordered Ga0.47In0.53As grown on substrates with the (001) surface tilted 4° towards {111}B are studied using spectroscopic methods as well as x-ray diffraction, transmission electron diffraction and dark-field transmission electron microscopy. The single variant ordering is proved by the absence of one class of the ordering induced 〈fraction SHAPE="CASE"〉12{111}B superlattice spots in transmission electron diffraction patterns as well as by the tilted polarization of the photoluminescence emerging from the samples cleaved edge. The temperature dependence of the luminescence peak position shows an anomalous behavior at low temperatures and a strong dependence of the peak position on the excitation power. From low temperature absorption measurements, we find a band gap reduction of 37 meV and a valence band splitting of 13.2 meV. © 1997 American Institute of Physics.
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  • 20
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We compare the field screening behavior of quantum-confined Stark effect modulator structures where the GaInAsP/InP heterojunction is in the intrinsic (standard structure) or in the doped regions (modified structure) at working wavelengths of 1.55 and 1.3 μm. The modified structures are obtained by expanding the GaInAsP confinement layers into the p-doped and n-doped regions without changing the total intrinsic layer thickness. The effectiveness of the InP heterobarriers for the holes on the p-side and for the electrons on the n-side is thereby lowered. A significant reduction of field screening for the modified structures is achieved. © 1996 American Institute of Physics.
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