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  • 1
    Electronic Resource
    Electronic Resource
    Zur Photolyse des ZinksulfidsProfessor Robert Schwarz zum 60. Geburtstage gewidmet (1947)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 255 (1947), S. 45-64 
    Details
    ISSN: 0372-7874
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es wird Über Versuche berichtet, die unternommen wurden, die Bedingungen zu studieren, die die Lichtempfindlichkeit des Zinksulfids beeinflussen.Es wird im einzelnen Folgendes festgestellt: 1 Die Belichtungstemperatur besitzt keinen wesentlichen Einfluß auf den Ablauf der Photolysereaktionen.2 Die Kristallstruktur ist entgegen der bisherigen Auffassung ohne wesentliche Bedeutung.3 Lichtempfindlichkeit und Korngrößenverteilung der Präparate gehen parallel, und es lassen sich aus einem Präparat durch Fraktionieren nach der Korngröße verschieden lichtempfindliche Fraktionen gewinnen. Es lassen sich weiterhin durch hydrothermale Synthese aus Zinksulfid reine Blenden herstellen, die dieselbe Lichtempfindlichkeit haben, wie hochgeglühte Präparate mit Wurtzitstruktur.Die Wirkung von Schwermetallzusätzen wird untersucht und auf Grund der von M. BODENSTEIN für die Silberhalogenide entwickelten Anschauungen diskutiert.Abschließend wird Über Versuche berichtet, die den Einfluß der Konzentrationsbedingungen bei der Fällung von reinem ZnS und von Lithopone zum Gegenstand haben.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19472550106
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  • 2
    Electronic Resource
    Electronic Resource
    Simulation of the maximum nitrate inflow (Imax) of lettuce (Lactuca sativa L.) grown under fluctuating climatic conditions in the greenhouse (1993)
    Springer
    Plant and soil 155-156 (1993), S. 163-166 
    Details
    ISSN: 1573-5036
    Keywords: lettuce ; maximum inflow (Imax) ; model ; nitrate ; relative growth rate ; root:shoot-ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Lettuce was grown in nutrient solution under fluctuating climatic conditions in the greenhouse. The maximum nitrate inflow (Imax) was measured twice a week to validate a model for calculating Imax, that was developed for constant conditions in a growth chamber. Growth and Imax were very similar between greenhouse and growth chamber plants, so that the model was able to predict Imax very precisely. The daily maximum nitrate inflow was calculated and its dependency on fluctuating temperature could be shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025009
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  • 3
    Electronic Resource
    Electronic Resource
    Influence of nitrate concentration at the root surface on yield and nitrate uptake of kohlrabi (Brassica oleracea gongyloides L.) and spinach (Spinacia oleracea L.) (1991)
    Springer
    Plant and soil 135 (1991), S. 205-211 
    Details
    ISSN: 1573-5036
    Keywords: kohlrabi ; nitrate ; spinach ; root ; root hairs ; uptake rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The objective of this study was to determine if plant roots have to take up nitrate at their maximum rate for achieving maximum yield. This was investigated in a flowing-solution system which kept nutrient concentrations at constant levels. Nitrate concentrations were maintained in the range 20 to 1000 μM. Maximum uptake rate for both species was obtained at 100 μM. Concentrations below 100 μM resulted in decreases in uptake rate per cm root (inflow) for both spinach and kohlrabi by 1/3 and 2/3, respectively. However, only with kohlrabi this caused a reduction in N uptake and yield. Thus indicating that this crop has to take up nitrate at the maximum inflow. Spinach, however, compensated for lower inflows by enhancing its root absorbing surface with more and longer roots hairs. Both species increased their root length by 1/3 at low nitrate concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010908
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  • 4
    Electronic Resource
    Electronic Resource
    Regulation of nitrogen uptake on the whole plant level (1996)
    Springer
    Plant and soil 181 (1996), S. 131-137 
    Details
    ISSN: 1573-5036
    Keywords: cucumber ; growth rate ; lettuce ; maximum inflow (Imax) ; model ; nitrate ; regulation ; uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The largest part of nitrogen requirements of crops is mostly covered by nitrate. The uptake of this ion is thermodynamically uphill and thus dependent on metabolism. This article considers regulation of N uptake in higher plants putting emphasis on NO3 - and the whole plant level. In field conditions the transport rate depends on the concentration at the root surface in Michaelis-Menten-Kinetics. Maximum net influx of NO3 - (Imax) was often reported at concentrations of 100 μM NO3 - and even lower. There are indications that for unrestricted growth the NO3 - concentration at root surface has to be in the order of magnitude allowing Imax if plants are not able to compensate for lower NO3 - concentrations by increasing root surface per unit of shoot. Imax is not a constant but depends for a given variety on N status of plants, the availability of NO3 - and plant age. The decrease of Imax with increasing plant age is closely related to relative growth rate as long as the relationship between N demand and new growth is linear and the root:shoot ratio keeps constant. It seems that Imax is a meaningful physiological characteristic of NO3 - uptake reflecting absolute N demand. There is evidence that shoot demand is linked to NO3 - uptake of the root through an amino acid transport pool cycling in the plant via phloem and xylem. The N demand of a crop depends on increase of dry mass and might not be linear if the “critical level” of nitrogen in plant dry matter changes during crop development or if retranslocation of nitrogen from older leaves to meristematic tissue occurs. Radiation and temperature drive plant growth and thus N demand of crops. These relationships can be described by mathematical models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011299
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  • 5
    Electronic Resource
    Electronic Resource
    A model relating the maximum nitrate inflow of lettuce (Lactuca satvia L.) to the growth of roots and shoots (1994)
    Springer
    Plant and soil 162 (1994), S. 249-257 
    Details
    ISSN: 1573-5036
    Keywords: lettuce ; maximum inflow (Imax) ; model ; nitrate ; relative growth rate ; root:shoot-ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The net inflow of nitrate can be calculated from the nitrate concentration at the root surface by means of the Michaelis-Menten equation. Because of maximum inflow (Imax) is not constant but varies with plant age and growing conditions, a model for calculating Imax during plant growth was derived. Lettuce was grown in nutrient solution. Variations in temperature, radiation and plant age were used to vary growth rates and N-demand of plants. There was a linear relationship between relative growth rates (RGR) and maximum nitrate inflow (Imax), that could be described by the following regression function: Imax = 0.24 + 6.57 RGR. A residual analysis showed a further influence on Imax from the root:shoot-ratio (RSR), the effects of which could be accounted for by including an e-function in the relationship: Imax = (0.27 + 10.63 RGR) e(−0.0017 RSR). This model for calculating Imax was validated in two further experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01347712
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  • 6
    Electronic Resource
    Electronic Resource
    Über das Schwefelmonoxyd. 4. Mitteilung. Die Oxydation des Schwefels (1934)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 220 (1934), S. 268-272 
    Details
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Oxydation von Schwefel wird unter verschiedenen Bedingungen auf die Entstehung von Schwefelmonoxyd hin untersucht.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19342200307
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis of (R)-Sulforaphane Using [cpru(R, R)-CHIRAPHOS)]+ as Chiral AuxiliaryEnantioselective organic syntheses using chiral transition metal complexes, part 3. For part 2 see ref. [1]. (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 713-716 
    Details
    ISSN: 0947-6539
    Keywords: asymmetric synthesis ; dioxiranes ; ruthenium ; sulforaphane ; sulfoxides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new enantioselective (80% ee) synthesis of (R)-sulforaphane and its epimer (S)-sulforaphane is described, which makes use of the pseudo-tetrahedral complex fragment [CpRu-(CHIRAPHOS)]+ as a chiral auxiliary. Reaction of the chloride complexes [CpRu(L-L)Cl] [L-L = 1,-bis(diphenylphosphino)ethane (dppe), (2S,3S)-and (2R,3R)-bis(diphenylphosphino)-butane ((S,S)- and (R, R)-CHIRAPHOS, respectively)] with phthalimidobutyl methyl sulfide gives the thioether complexes [CpRu(L-L)(MeSC4H8NPhth)]PF6. Oxygen transfer from dimethyldioxirane (DMD) produces the corresponding sulfoxide complexes in high yield and high diastereoselectivity. Cleavage of the phthaloyl group with aqueous hydrazine and subsequent reaction with thiophosgene yields the sulforaphane complexes [CpRu(L-L)(MeS(O)C4H8NCS)]PF6. Treatment of these with sodium iodide finally liberates the sulforaphane without noticeable racemization.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030510
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  • 8
    Electronic Resource
    Electronic Resource
    Van der Waals model for filled rubbers with modified interfacial contacts (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 35 (1988), S. 345-362 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It is shown how the global deformation mechanism in filler-loaded vulcanizates were modified by additional filler-to-matrix bonds. A quantitative description is given in terms of an extended van der Waals treatment including the formulation of a reduced mechanical equation of state. An interpretation of the Mullins softening is presented.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070350206
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  • 9
    Electronic Resource
    Electronic Resource
    Scale-down and optimization studies of the gluconic acid fermentation by Gluconobacter oxydans (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 711-720 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: To simulate production-scale conditions of gluconic acid fermentation by Gluconobacter oxydans, different experimental setups are presented in this study. From the determination of the time constants of a production-scale reactor, it can be concluded that mixing and oxygen transfer are the rate-limiting mechanisms. This results in oxygen concentration gradients which were simulated in a one-compartment reactor in which the oxygen concentration was fluctuated by a fluctuated gassing with air and nitrogen. It could be concluded that only very long periods of absence of oxygen (ca. 180 s) results in lower specific oxygen uptake rates by Gluconobacter oxydans. From scale-down studies carried out in a two-compartment system to simulate a production-scale reactor more accurately, it could be concluded that not only the residence time in the aerated part of the system is important, but the liquid flow in between the different parts of the reactor is also an essential parameter. It could also be concluded that the microorganisms are not influenced negatively by the fluctuated oxygen concentrations with respect to their maximal oxidation capacity. The two-compartment system can also be used for optimization experiments in which the “aerated” compartment was gassed with pure oxygen. From these experiments it was concluded that also a short residence of the cells at high oxygen concentrations diminished the growth and product formation rates. These experiments show the necessity of the scale-down experiments if optimization is carried out. The two-compartment system presented in this study is a very attractive tool for reliable scale-down experiments.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270521
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  • 10
    Electronic Resource
    Electronic Resource
    Preparation of 1-Hydroxycyclopentanecarboxylic Acid Derivatives from a Chiral Equivalent of Glycolic Acid (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 477-483 
    Details
    ISSN: 1434-193X
    Keywords: Radical reactions ; Glycolic acid ; Asymmetric synthesis ; Annulation ; Selenium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -The stereoselective preparation of 1-hydroxycyclopentanecarboxylic acid derivatives is reported. The key reaction is either a radical cyclization or a radical annulation mediated by the transfer of a phenylseleno group. The radical precursors are easily synthesized by two consecutive enolate alkylations. Excellent stereochemical control for the quaternary C(1) stereogenic center has been achieved.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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