Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    ISSN: 1432-2242
    Keywords: Key wordsZea mays ; Invertase ; Miniature1 seedmutant ; Kernel culture ; Futile cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Cell wall-bound invertase (CWI) is spatially and temporally the first enzyme which metabolizes the incoming sucrose in developing seed of maize (Zea mays). Our previous studies have shown that the cell wall-bound invertase-2 (INCW2) isozyme encoded by the wild-type gene of the Miniature1 (Mn1) seed locus plays a critical role in seed development. Null mutations of the gene, such as the mn1 seed mutant which lacks invertase activity, are associated with a loss of ∼70–80% of the normal seed weight. We show here that under in vitro kernel culture conditions the hexose-based medium was similar to the sucrose-based medium in promoting the normal development of kernels of the Mn1, but not of the mutant mn1, genotype. Anatomical, biochemical, and immunohistological data showed that the mn1 kernels retain their mutant phenotype regardless of the presence of sucrose or hexoses in the culture media. The most drastic changes in the mn1 seed mutant were associated with a significant reduction in the size of the endosperm, but not in the pattern or the level of starch localization. Because Mn1 expression was temporally coincident with the endosperm cell divisions, INCW2 must play a critical role in providing hexose sugars for mitotic division, and only a minor role in generating carbon skeletal substrates for starch biosynthesis in the early stages of endosperm development. Furthermore, a lack of the wild-type seed phenotype of the mn1 mutant in hexose media suggests that a metabolic release of hexoses catalyzed by INCW2, rather than an exogenous source, is critical for both generating appropriate sugar-sensing signals for gene expression and for normal endosperm development.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-7373
    Keywords: malignant glioma ; chemotherapy ; carmustine ; cisplatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twenty-two patients, aged 16 to 67, who had malignant gliomas after surgical resection were treated with carmustine and cisplatin intravenous infusion before, during, and after radiotherapy. All patients had subtotal or total resection, or biopsy as the initial procedure. Twenty-one patients who had at least 2 cycles of chemotherapy and finished the whole course of radiotherapy were considered to be evaluable for responses. Among them, 5 had glioblastoma multiforme, 16 had anaplastic astrocytoma. The median time to tumor progression was 35 weeks (range 12–130 weeks) and median survival time was 66 weeks (range 10–156 weeks). Early progression occurred more frequently in patients with biopsy only and subtotal resection, and in patients with glioblastoma than in those with anaplastic astrocytoma. This combined modality treatment program was associated with reversible hematologic toxicity which was severe in 2 patients, and with ototoxicity in 1 patient, nephrotoxicity in 2 patients. Combination of carmustine and cisplatin with cranial irradiation for malignant gliomas is moderately toxic and appears to offer no obvious survival advantage compared with radiation therapy plus BCNU alone.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-2754
    Keywords: quasi-wavelets ; Runge-Kutta method ; Burgers' equations ; O351.2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Mathematics , Physics
    Notes: Abstract A quasi-wavelet based numerical method was introduced for solving the evolution of the solutions of nonlinear paritial differential Burgers' equations. The quasi wavelet based numerical method was used to discrete the spatial derivatives, while the fourth-order Runge-Kutta method was adopted to deal with the temporal discretization. The calculations were conducted at a variety of Reynolds numbers ranging from 10 to unlimited large. The comparisons of present results with analytical solutions show that the quasi wavelet based numerical method has distinctive local property, and is efficient and robust for numerically solving Burgers' equations.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1434-4483
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Description / Table of Contents: Zusammenfassung Die Strahlungsbilanz wurde über einem seichten See (Albertsee, Südaustralien) ein Jahr lang gemessen. Mittlere Tageswerte der Strahlungsbilanz (R n ), der Globalstrahlung (Q) und der Albedo (α) wurden bestimmt, aus denen lineare Zusammenhänge zwischen Strahlungsbilanz und Globalstrahlung für ein Jahr und für einzelne Jahreszeiten abgeleitet wurden. Für das Jahr gilt: (1) unter wolkenfreien BedingungenR n =0.750Q−13.8 Wm−2 (2) für alle TageR n =0.734Q−11.9 Wm−2 Jahreszeitliche Zusammenhänge wurden ebenfalls bestimmt, doch sind diese wahrscheinlich nur für das lokale, jahreszeitliche Klima des Sees zutreffend.
    Notes: Summary The radiation balance over a shallow lake, Lake Albert, South Australia, has been measured over the period of a year. Mean daily values of net radiation (R n ), global radiation (Q) and albedo (α) have been obtained from which linear relationships between net radiation and global radiation are determined for annual and seasonal periods. For annual period: (i) cloud free conditionsR n =0.750Q−13.8 Wm−2 (ii) all daysR n =0.734Q−11.9 Wm−2 Seasonal relations are determined, however they are more likely to be unique to the seasonal climate of the lake.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1069-8299
    Keywords: shell element ; large strain ; sheet metal stamping ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The paper presents a general method of large strain determination over the deformed surface of a sheet metal stamping. It is demonstrated that the conventional degenerated shell element with two normal rotation degrees of freedom is not suitable for large deformation, especially when large element rotation is present. This inaccuracy is primarily caused by the fact that the displacement field description used in the degenerated shell element is only a first-order approximation with respect to the two rotation degrees of freedom, and is therefore suitable only for small rotation angles. The new method presented in this paper replaces the two rotation DOFs with three new degrees of freedom to describe the rotation of the surface normal so that the element deformation can be accurately described with no limitation on the amount of deformation and rotation involved. The advantages of this new method are: (i) a linear and accurate expression of the displacement field in terms of nodal DOFs is obtained; (ii) the formulation is easily incorporated into any existing degenerated shell elements; (iii) the strain calculation is accurate for any amount of element rigid body rotation; (iv) if the method is used in surface grid analysis, the algorithm will not only provide correct surface strains, but also their variation through the thickness direction, i.e. the bending deformation. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary  In the central region of Taiwan, ozone episodes occur most often during autumn. Two field experiments were conducted during the autumns of 1998 and 1999 to analyze the vertical profile of the boundary layer and determine its effects on ozone concentration over the region. The vertical virtual potential temperature and wind profiles were derived from tethersonde data. The NOx, NMHC and O3 concentration vertical profiles were monitored up to a height of 500 meters using black-covered Teflon tedler sampling bags. During the experimental periods, nighttime terrestrial long wave radiation could cause the inversion height to reach 500 meters by the following morning. It was shown that these types of synoptic structures suppress the vertical diffusion of NOx, NMHC and O3. During the daytime, measurements indicate that pollutants were well mixed in the upper portion of the mixing layer. At night, the ground level ozone concentration was on the decrease but increased with altitude to a height of 500 m. The NOx decreased with altitude whereas the NMHC showed no significant variations.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...