ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Application of a Si-diode detector for fusion product measurements in ASDEX Upgrade (1997)

Ullrich, W. ; Bosch, H.-S. ; Hoenen, F.

[S.l.] : American Institute of Physics (AIP)

Review of Scientific Instruments 68 (1997), S. 4434-4438

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ISSN: 1089-7623

Source: AIP Digital Archive

Topics: Physics , Electrical Engineering, Measurement and Control Technology

Notes: The efficient confinement of the energetic charged fusion products and the complete transfer of their kinetic energy to the plasma is of great importance for the realization of a fusion reactor which will depend on alpha-particle heating. In todays fusion experiments with deuterium plasmas, this aspect can be investigated using the 1 MeV tritons from the d(d,p)t reaction. The slowing down behavior of these tritons can be studied by measuring the 14 MeV neutrons from the t(d,α)n reaction (triton burnup). At ASDEX Upgrade a time-resolved diagnostic based on a silicon barrier detector has been installed to measure the time evolution of the 14 MeV neutron rate. Using the Si(n,p)Al and Si (n,α)Mg reactions the high energy neutrons, with an energy above the 6 MeV threshold, are converted to charged particles directly inside the semiconductor diode. The complete functionality of the detector system is demonstrated by the successful measurement of the complex spectrum of the charged reaction products in silicon triggered by fusion neutrons during plasma discharges. As an integral component of this diagnostic a time dependent burnup code based on classical slowing-down theory has been developed for the use at ASDEX Upgrade to analyze the complex time evolution of the 14 MeV neutron rate. First measurements are compared to the results of the code. A new application for such detectors is proposed, as in conjunction with the materials of the tokamak structure it can be operated simultaneously as an in situ activation system. © 1997 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.1148410

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2

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Role of ammonium accumulation in bacteria-induced hypersensitive and compatible reactions of tobacco and cotton plants (1993)

Ullrich, W. R. ; Kunz, G. ; Stiller, A. ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

Physiologia plantarum 89 (1993), S. 0

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ISSN: 1399-3054

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Leaves of 12-week-old tobacco plants (Nicotiana tabacum L. cv. Samsun NN) were infiltrated with suspensions of Pseudomonas syringae pv, pisi (DSM 50291) to induce hypersensitive reaction (HR). Cotyledons of 2-week-old cotton plants (Gossypium hirsutum L. cv. Acala 442 and Coker BR) were infiltrated with Xanthomonas campestris pv. malvacearum (race 10) to induce the disease. In tobacco, HR-related increases in NH+4 levels started within 2 h after infection and continued up to the time of tissue decay. Increase of NH+4 and especially K+ efflux were detected in intercellular washing fluids (IWF). Antibiotics stopped and later reverted NH+4 production and K+ efflux, but only if applied within 2 h after infection. When 10 mM NH+4 was injected into leaves, it was rapidly consumed from the IWF, and also, although more slowly, within the leaf cells. The concomitant K+ efflux was strong but delayed, and most of the K+ was reabsorbed after 2 h. Bacterial cell multiplication in HR stopped before the appearance of HR symptoms and cell necrosis. In the compatible reaction in cotton cotyledons, both NH+4accumulation and K+ efflux proceeded much more slowly than in the HR with tobacco, and bacteria continued to multiply until general cell necrosis occurred. The compatible reaction developed faster in constant darkness than in a light/dark rhythm. Bacterial enzymes produced NH+4, mainly from proteins of host cells, in both light and darkness. Continuous light delayed the main peak of both NH+4 production and K+ efflux. High CO2 concentration inhibited both processes, thus indicating that photorespiration plays a role in enhancing the release of free ammonium during bacterial pathogenesis. This is supported by shifts in the pattern of amino acids. The results demonstrate the accelerating and aggravating effect of ammonium in pathogenesis and HR, though ammonium is not the primary agent.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1399-3054.1993.tb05228.x

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3

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Effects of solar radiation on photoorientation, motility and pigmentation in a freshwater Peridinium

Hader, D.-P. ; Hader, M. ; Liu, S.-M. ; [et al.]

Amsterdam : Elsevier

Biosystems 23 (1990), S. 335-343

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ISSN: 0303-2647

Keywords: Dinoflagellates ; Image analysis ; Motility ; Peridinium gatunense ; Phototaxis ; Pigment bleaching ; Solar radiation

Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Topics: Biology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1016/0303-2647(90)90015-S

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4

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Darstellung und struktur von 1-metalla-2,3,4-triazolen des molybdans und wolframs

Stegmair, C.M. ; Schutt, W. ; Ullrich, W. ; [et al.]

Amsterdam : Elsevier

Journal of Organometallic Chemistry 447 (1993), S. 251-257

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ISSN: 0022-328X

Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Topics: Chemistry and Pharmacology

Type of Medium: Electronic Resource

URL: http://linkinghub.elsevier.com/retrieve/pii/0022-328X(93)80246-8

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5

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Intracellular translocation of ATP, ADP and inorganic phosphate in leaf cells of elodea densa in relation to photosynthesis

Santarius, K.A. ; Heber, U. ; Ullrich, W. ; [et al.]

Amsterdam : Elsevier

Biochemical and Biophysical Research Communications 15 (1964), S. 139-146

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ISSN: 0006-291X

Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Topics: Biology , Chemistry and Pharmacology , Physics

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1016/0006-291X(64)90313-4

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6

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Persistence of Complexed Acidic Phospholipids in Rapidly Mineralizing Tissues is Due to Affinity for Mineral and Resistance to Hydrolytic Attack: In Vitro Data (1996)

Boskey, A. L. ; Ullrich, W. ; Spevak, L. ; [et al.]

Springer

Calcified tissue international 58 (1996), S. 45-51

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ISSN: 1432-0827

Keywords: Key words: Hydroxyapatite — Complexed acidic phospholipids — Liposomes — Phospholipase A2.

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Abstract. Acidic phospholipids, complexed with calcium and inorganic phosphate, are components of extracellular matrix vesicles. Both the complexed acidic phospholipids and matrix vesicles have previously been shown to serve as hydroxyapatite (HA) nucleators in solution and when implanted in a muscle pouch. The present study supplies evidence that complexed acidic phospholipids can persist in mineralizing tissues both because of their affinity for HA and because of their resistance to hydrolysis by phospholipase A2. Calcium-phosphatidylserine-phosphate complex (CPLX-PS) synthesized with 14C-labeled phosphatidylserine (PS) was used to measure CPLX-PS affinity for HA using a Langmuir adsorption isotherm model. The affinity was shown to be higher and more specific than that of PS itself (K = 8.66 ml/μmol; N, the number of binding sites = 20.4 μmol/m2 as compared with previously reported values for PS of K = 3.33 ml/μmol, and N = 4.87 μmol/m2). Incorporated into synthetic liposomes and incubated in a calcium phosphate solution in which mineralization is induced by an ionophore, CPLX-PS showed behavior distinct from free PS. As previously reported, PS in these liposomes totally blocked HA formation. On the other hand, CPLX-PS in similar concentrations had a varied response, having no effect, slightly inhibiting, or actually promoting HA formation. CPLX-PS was also shown to be a poorer substrate for phospholipase A2 than PS, with Km = 4.63 mM for CPLX-PS and Km = 0.27 mM for PS; and Vmax= 0.029 ml/minute for CPLX-PS and Vmax= 0.066 ml/minute for PS. These data explain how complexed acidic phospholipids may persist in the growth plate and facilitate initial mineral deposition.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002239900009

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7

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Stoichiometry between photosynthetic nitrate reduction and alkalinisation by Ankistrodesmus braunii in vivo (1975)

Eisele, R. ; Ullrich, W. R.

Springer

Planta 123 (1975), S. 117-123

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ISSN: 1432-2048

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary The uptake of nitrate or nitrite in the light, the release of nitrite and ammonia, and the corresponding alkalinisation of the medium were measured in synchronous Ankistrodesmus braunii (Naeg.) Brunnth. The increase in the OH− concentration in the medium reflects a stoichiometric ratio between OH− and NO3 − of 1.3–1.8 in air, reaching almost 2.0 in CO2−free air or nitrogen. At low CO2 concentrations a large proportion of the nitrogen taken up as nitrate is released as ammonia, much less as nitrite. The stoichiometry of alkalinisation and NO3 − or NO2 − uptake can be quantitatively explained by assuming: 1) a counter-transport, at a ratio of 1:1, of OH− against NO3 − at the plasmalemma and of OH− against NO2 − at the chloroplast envelope, and 2) a co-transport of 1:1 of OH− and NH4 + to the medium through both membranes. The first OH− required is formed by proton consumption in nitrite reduction, the second OH− by proton consumption in the formation of NH4 + ions. Transport of K+, Na+ and Ca2+ is not or only scarcely involved. This proposed transport system could provide charge equilibrium between inside and outside the cells and could enable the cells to avoid nternal pH changes in nitrate and nitrite reduction.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00383860

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8

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Die Bildung von Polyphosphaten bei Ankistrodesmus braunii durch Photophosphorylierung im Rotlicht von 683 und 712 nm unter Stickstoffatmosphäre (1969)

Ullrich, W. ; Simonis, W.

Springer

Planta 84 (1969), S. 358-367

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ISSN: 1432-2048

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary A simplified extraction procedure was used to study the effect of red and far-red light (683 and 712 nm) on the incorporation of 32P and on the distribution pattern of various phosphate fractions in 8 min-experiments under nitrogen. Nitrogen was used to avoid competition for energy-rich phosphate bonds between CO2-fixation and the formation of polyphosphates. The total incorporation of 32P was higher in red than in far-red light, and so was the percentage of the acidsoluble organic phosphate. In the absence of oxygen the incorporation in the dark was rather low and mainly confined to orthophosphate. The ratio between the amount of labelling of polyphosphates and that of acid-soluble organic phosphates was higher in far-red light and in the dark than in red light. DCMU, even in a nitrogen atmosphere, produced a servre inhibition in red light. This inhibition increased with increasing light intensity. The labelling of organic phosphates was more affected than that of polyphosphates, while orthophosphate incorporation was least inhibited. In far-red light, DCMU exerted little influence except at a rather high light intensity, showing that cyclic photophosphorylation was proceeding alone. Antimycin A, on the other hand, was almost ineffective in strong red light, but produced a serious inhibition in far-red light. In red light of medium intensity, antimycin effected some inhibition, although much less than DCMU. Under these conditions the effect of the two inhibitors was additive when they were applied together. Labelling of polyphosphates was more sensitive to antimycin A than labelling of acid-soluble organic phosphates. It may be concluded from the data presented that far-red light produces conditions for pure cyclic photophosphorylation, whereas a large proportion of the photophosphorylation taking place in red light in the absence of CO2 and exogenous oxygen might be regarded as “pseudocyclic”. The distribution pattern of the phosphorylated fractions under the different conditions suggests that polyphosphate formation in the light is favoured but not exclusively effected by cyclic photophosphorylation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00396428

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9

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Zur Wirkung von Sauerstoff auf die 32P-Markierung von Polyphosphaten und organischen Phosphaten bei Ankistrodesmus braunii im Licht (1970)

Ullrich, W. R.

Springer

Planta 90 (1970), S. 272-285

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ISSN: 1432-2048

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary Short time incorporation of 32P was carried out with synchronised algae (young cells) depleted of phosphate. For the separation and determination of the acid-insoluble phosphate fractions of the cells an improved fractionation procedure was applied. In order to exclude competition by carbon dioxide all experiments were done in the absence of CO2. Compared with nitrogen, CO2-free air produces an increase in the labelling of phosphorylated compounds in the light. In strong white light, at high pH, air effects a remarkable increase of 32P in the acid-insoluble phosphate (P u), mainly in inorganic polyphosphates (P ul), whereas the total phosphate uptake remains almost unchanged. The increase in labelling of acid-insoluble phosphate is, therefore, accompanied by a substantial decrease in the labelling of acid-soluble compounds (P l). In weak white light or in far-red light, at low pH even in strong white or red light, an increase of phosphate uptake and an increased labelling of the acid-stable organic acid-soluble fraction (P os) is observed instead. The effect of oxygen increases somewhat with increasing light intensity up to light saturation, and it increases markedly with increasing oxygen concentration. An essential contribution by oxidative phosphorylation to this oxygen effect can be ruled out on account of its much higher sensitivity to oxygen. Pseudocyclic photophosphorylation is also not regarded as the main force because of its higher oxygen affinity. Occurrence of photorespiration has not been clearly established so far in related algae (Chlorella), and its use for phosphorylation is unknown. A better, although not complete explanation is given by comparing the oxygen effect with the well-known inhibition of photosynthesis by oxygen (Warburg effect), which leads to an increase in glycolate formation and a simultaneous decrease in the pool sizes of carbon reduction cycle intermediates, even in the absence of CO2. Since the photophosphorylation process, as well as the photosynthetic electron flow, seem unaffected by high oxygen concentrations whereas the formation of organic phosphate compounds is partially inhibited, excess ATP may be available for polyphosphate synthesis. This explanation would be consistent with the assumption that polyphosphate-ADP kinase mediates an equilibrium between ATP and polyphosphates, mainly at higher pH. At low pH and in other cases the excess ATP might be available for an increased phosphate uptake and for phosphorylation of endogenous carbohydrates.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00387179

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