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  • 1
    Electronic Resource
    Electronic Resource
    Description and Application of Microwave Titrations. Determination of the Reaction Rate and Stoichiometric Composition of Complexes. (1965)
    s.l. : American Chemical Society
    Analytical chemistry 37 (1965), S. 229-233 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60221a012
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  • 2
    Electronic Resource
    Electronic Resource
    Physiological effects of long-term exposure to low and moderate concentrations of atmospheric NH3 on poplar leaves (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 12 (1989), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. Poplar shoots (Populus euramericana L.) obtained from cuttings were exposed for 6 or 8 weeks to NH3 concentrations of 50 and 100 μgm−3 or filtered air in fumigation chambers. After this exposure the rates of NH3 uptake, transpiration, CO2 assimilation and respiration of leaves were measured using a leaf chamber. During the long-term exposure also modulated chlorophyll fluorescence measurements were carried out to obtain information about the photosynthetic performance of individual leaves. Both fluorescence and leaf chamber measurements showed a higher photosynthetic activity of leaves exposed to 100 μg NH3 m−3. These leaves showed also a larger leaf conductance and a larger uptake rate of NH3 than leaves exposed to 50 μg m−3 NH3 or filtered air. The long-term NH3 exposure did not induce an internal resistance against NH3 transport in the leaf, nor did it affect the leaf cuticle. So, not only at a short time exposure, but also at a long-term exposure NH3 uptake into leaves can be calculated from data on the boundary layer and stomatal resistance for H2O and ambient NH3-concentration. Furthermore, the NH3 exposure had no effect on the relation between CO2-assimilation and stomatal conductance, indicating that NH3 in concentrations up to 100 μg m−3 has no direct effect on stomatal behaviour; for example, by affecting the guard or contiguous cells of the stomata.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1989.tb01969.x
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  • 3
    Electronic Resource
    Electronic Resource
    Physiological effects of long term exposure to low concentrations of SO2 and NH3 on poplar leaves (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 82 (1991), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Shoots of poplar (Populus euramericana L. cv. Flevo) were exposed to filtered air, SO2, NH3 or a mixture of SO2 and NH3 for 7 weeks in fumigation chambers. After this exposure gas exchange measurements were carried out using a leaf chamber. As compared to leaves exposed to filtered air, leaves pretreated with 112 μg m−3 SO2 showed a small reduction in maximum CO2 assimilation rate (Pmax) and stomatal conductance (gs). They also showed a slightly higher quantum yield and dark respiration. In addition, the fluorescence measurements indicated that the Calvin cycle of the leaves pretreated with 112 μg m−3 SO2 was more rapidly activated after transition from dark to light. An exposure to 64 μg m−3 NH3 had a positive effect on Pmax, stomatal conductance and NH3 uptake of the leaves. This positive effect was counteracted by an SO2 concentration of 45 μg m−3. The exposure treatments appeared to have no effect on the relationship between net CO2-assimilation and gs. Also, no injury of the leaf cuticle or of epidermal cells was observed.Resistance analysis showed that NH3 transfer into the leaf can be estimated from data on the boundary layer and stomatal resistance for H2O transfer and NH3 concentration at the leaf surface, irrespective of whether the leaves are exposed for a short or long time to NH3 or to a mixture of NH3 and SO2. In contrast SO2 uptake into the leaves was only partly correlated to the stomatal resistance. The results suggest a large additional uptake of this gas by the leaves. The possibility of a difference in path length between SO2 and H2O molecules is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1991.tb02899.x
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of low-level ozone exposure under ambient conditions on photosynthesis and stomatal control of Vicia faba L. (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 13 (1990), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. Gas exchange rates of 4-week-old faba bean plants were measured after exposure to ozonc (120 μg m3) in an open top chamber for 8 h per day over a period of 2 weeks. The exchange rates were compared with those of control plants. Plants exposed between mid-May and the end of July 1987 showed a minor negative effect on stomatal conductance, while there was no effect on photosynthesis and respiration. Plants exposed between the end of August and early October showed a negative effect on both stomatal conductance and photosynthesis. In addition, the dark respiration rate was slightly increased. It is concluded that ozone can have a direct effect on the stomata as well as on the photosynthetic system and that the stomata are more sensitive than the photosynthetic system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1990.tb01323.x
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  • 5
    Electronic Resource
    Electronic Resource
    The NO2-O3 system at sub-ppm concentrations: Influence of temperature and relative humidity (1985)
    Springer
    Journal of atmospheric chemistry 2 (1985), S. 387-403 
    Details
    ISSN: 1573-0662
    Keywords: Night-time NO2 oxidation ; nitrate radical ; nitrogen pentoxide ; wall scavening ; stoichiometry ; kinetic study ; temperature ; relative humidity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The stoichiometry and kinetics of the reaction of NO2 with O3 at sub-ppm concentration level have been investigated as a function of temperature and relative humidity. The experiments were performed in a continuous flow reactor using chemiluminescent and wet chemical methods of analysis. The rate constant found can be described by the Arrhenius expression: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaiikaiaaik% dacaGGUaGaaGyoaiaaiEdacqGHXcqScaaIWaGaaiOlaiaaigdacaaI% 0aGaaiykaiabgEna0kaaigdacaaIWaWaaWbaaSqabeaacqGHsislca% aIXaGaaG4maaaakiaabwgacaqG4bGaaeiCaiaacIcadaWcgaqaaiaa% cIcacqGHsislcaaIYaGaaGOnaiaaikdacaaIWaGaeyySaeRaaGyoai% aaicdacaGGPaaabaGaamivaiaacMcacaqGGaGaae4yaiaab2gadaah% aaWcbeqaaiaabodaaaGccaqGGaWaaSGbaeaacaqGTbGaae4BaiaabY% gacaqGLbGaae4yaiaabwhacaqGSbGaaeyzamaaCaaaleqabaGaaeyl% aiaabgdaaaaakeaacaqGZbWaaWbaaSqabeaacaqGTaGaaeymaaaaaa% aaaaaa!62A3!\[(2.97 \pm 0.14) \times 10^{ - 13} {\text{exp}}({{( - 2620 \pm 90)} \mathord{\left/ {\vphantom {{( - 2620 \pm 90)} {T){\text{ cm}}^{\text{3}} {\text{ }}{{{\text{molecule}}^{{\text{ - 1}}} } \mathord{\left/ {\vphantom {{{\text{molecule}}^{{\text{ - 1}}} } {{\text{s}}^{{\text{ - 1}}} }}} \right. \kern-\nulldelimiterspace} {{\text{s}}^{{\text{ - 1}}} }}}}} \right. \kern-\nulldelimiterspace} {T){\text{ cm}}^{\text{3}} {\text{ }}{{{\text{molecule}}^{{\text{ - 1}}} } \mathord{\left/ {\vphantom {{{\text{molecule}}^{{\text{ - 1}}} } {{\text{s}}^{{\text{ - 1}}} }}} \right. \kern-\nulldelimiterspace} {{\text{s}}^{{\text{ - 1}}} }}}}\] and are independent of the relative humidity. As commonly encountered in previous studies a lower-than-two reaction stoichiometry is observed. Heterogeneous reactions occurring at the reactor wall seem to be essential in the reaction mechanism. The NO3 wall conversion to NO2 and the N2O5 wall scavenging in the presence of H2O are suggested to account for the observed stoichiometric factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00130750
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  • 6
    Electronic Resource
    Electronic Resource
    The determination of NH3-concentration gradients in a spruce forest using a passive sampling technique (1993)
    Springer
    Water, air & soil pollution 69 (1993), S. 321-335 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract In order to estimate the influence of NH3 on a forest in a clean atmosphere, the quality of the atmosphere in Sumava, South-Bohemia, was determined in September–October 1988. In this period the NOX, SO2, and aerosol concentrations were extremely low. The N-input into the forest margin amounted to 10–15 kg ha−1 in these two months, based on a deposition velocity of 3 cm s−1 and an average concentration of 9 μg m−3 NH3. The maximum hourly average ozone concentrations were found to be 50 to 100 μg m−3. There exists a strong relation between the ambient NH3 concentration profiles and the stable occupation. The concentration inside the stables exceeded the no-adverse-effect level for cows of 7.6 mg m−3. This publication forms the basis for the estimation of the exposure of the forest to NH3 and the interpretation of the observed effects as published elsewhere (Mejstřík et al., unpublished).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00478168
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  • 7
    Electronic Resource
    Electronic Resource
    Mathematical descriptions of hybridoma culture kinetics: I. Initial metabolic rates (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 32 (1988), S. 491-506 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The lack of quantitative descriptions of mammalian culture kinetics limits the ability to optimally design and control cell culture bioreactors. This limitation is ad dressed by developing mathematical equations relating the initial growth rate and the antibody productivity of the hybridoma cell line, CRL-1606, to its environmental state. This initial rate approach, in contrast with steady state analysis of chemostat cultures, approximates steady state behavior, since the rates were measured over brief time intervals and at low cell concentrations (〈 50,000 cells/mL). The advantage of this approach is that it is much faster than the chemostat approach.An equation for the growth rate was developed that superimpoed Monod equations in serum and glutamine with “noncompetitive” -type inhibition constants were inversely proportional to the lactate and ammonium concentrations. The Monod constant is critical for relating initial, low cell level culture states to other states.Lactate was found to be the only environmental parameter that significantly inhibited antifibronectin monoclonal antibody production by the CRL-1606 hybridimas. Volumetric productivity was strictly related to culture viability, which was observed to decline at growth rates below 0.02h-1. Lactate was also found to significantly inhibit ammonium production.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260320412
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  • 8
    Electronic Resource
    Electronic Resource
    Mathematical descriptions of hybridoma culture kinetics: II. The relationship between thiol chemistry and the degradation of serum activity (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 440-450 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The growth rate of the hybridoma cell line ATCC-CRL-1606 in low serum medium declines rapidly with time after inoculation. To characterize this phenomenon, the stability of the growth-promoting activity of serum was investigated. The activity of serum was found to de grade with time, and was stabilized by alterations in the medium formulation that acted to lower the oxidation/reduction potential. This included both the addition of thiols and the elimination of disulfides from the medium. Additionally, cysteine and other thiols were shown to stimulate growth in low serum, low cell density cultures, suggesting that thiols may be rate-limiting in low serum medium. Stimulation of growth by thiol addition was less significant at high cell levels, implying that the cells themselves may be acting to reduce their environment. A hypothesis is presented based on these results which suggests that the actual rate-limiting moieties in low serum cultures may be dithiols.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330409
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