ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    ISSN: 1862-0760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In the eighties, Iwahara discovered that doped Sr and Ba cerates show significant proton conduction, at high temperature, and in hydrogen- or water-containing atmosphere [1]. Begin ‘90 it was proved that also doped zirconates (Sr, Ba, Ca) join this family of proton conducting perovskites [2]. Within this group, indium doped CaZrO3 is one of the more interesting materials for applications, being mechanically and chemically particularly stable, and producible in very dense form. Specifically, it was already succesfully incorporated in a hydrogen sensor for liquid aluminium [3]. In principle, this sensor works as a simple electrochemical hydrogen concentration cell described by Nernst. However, as already remarked phenomenologically from the beginning [1], a hydrogen concentration cell using these perovskites shows the theoretically predicted emf, only in the presence of humidity. In this paper we want to go deeper into the reasons for this phenomenon.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Plant ecology 145 (1999), S. 83-90 
    ISSN: 1573-5052
    Keywords: Dispersal ; Disturbance ; Granivory ; Germinable seed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sources of seed for seedbank build-up in an acidic grassland were identified from analysis of differences in seedbank build-up over one year between plots where the input of rabbit pellets to ‘seed-free’ soil had either been left or removed. In parallel, the flux of seed arriving in rabbit pellets was monitored. Pellet seed content and total seed input were highest in late summer/early autumn and again in the spring. The seed content of the pellets was dominated by a small number of species: Sagina apetala, Senecio jacobaea, Urtica dioica and Veronica arvensis. Smaller seeded species were more likely to be present as germinable seed in the pellets. Seedbank build-up as a result of wind, splash or adhesive dispersal totalled 547 seedsm2. The additional effect of allowing seed input in pellets was 267 seedsm2, though this increase was not significant. The total increase in seedbank over one year was equivalent to 15–20% of the seedbank present in undisturbed soil. Eight species showed a significant build-up of seed in the seedbank over one year as a result of all means of dispersal, but only Myosotis discolor showed a significantly higher soil germinable seed content in the plots where pellets had been allowed to remain in situ. The build-up of seed in the seedbank is contrasted with the build-up of vegetation on disturbed areas within the same system.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0044-2313
    Keywords: Selenites ; hydrates ; X-ray ; IR ; crystal structure ; pseudosymmetry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polymorphic and Pseudosymmetrical Hydrates MSeO3 · H2O (M = Mn, Co, Ni, Zn, Cd)By crystallization from aqueous solutions of MSeO3 and M(HSeO3)2, the selenites MSeO3 · H2O (M = Mn, Co, Ni, Zn, Cd) were obtained and characterized by means of X-ray diffraction and IR-spectroscopy. The crystal structure of ZnSeO3 · H2O was determined. The IR spectra indicate that the hydrates are isotypic and contain H2O molecules of symmetry mm2. However, the X-ray data show different structure types with H2O molecules of site symmetry m or 1. CdSeO3 · H2O and MnSeO3 · H2O are isotypic (o.rh., MnSeO3 · D2O type). CoSeO3 · H2O (mon.) as well as the isotypic NiSeO3 · H2O and ZnSeO3 · H2O (mon.) form new structure types. These findings are discussed on the basis of the crystal structure of ZnSeO3 · H2O (P21/n, a = 477.9(1), b = 1319.4(5), c = 570.1(1) pm, β = 90.84(2)°, Z = 4, Dx = 3.886 g · cm-3, R = 0.035 for 722 reflections with I 〉 2σ1) and the local pseudosymmetry of its components, i.e., layers ∞2[ZnSeO3 · H2O] of ZnO6 octahedra sharing four equatorial vertices, SeO32- anions and H2O molecules.
    Notes: Durch Kristallisation aus MSeO3- und M(HSeO3)2-Lösungen wurden die Selenite MSeO3 · H2O (M = Mn, Co, Ni, Zn, Cd) erhalten und röntgenographisch sowie IR-spektroskopisch charakterisiert. Von ZnSeO3 · H2O wurde die Kristallstruktur bestimmt. Die IR-Spektren deuten auf Isotypie der Hydrate und H2O-Moleküle der Symmetrie mm2. Die Röntgenbeugungsdaten zeigen dagegen das Vorliegen verschiedener Strukturtypen mit H2O-Molekülen der Lagesymmetrie m oder 1. CdSeO3 · H2O und MnSeO3 · H2O sind isotyp (o.rh., MnSeO3 · D2O-Typ). CoSeO3 · H2O (mon.) sowie die isotypen NiSeO3 · H2O und ZnSeO3 · H2O (mon.) kristallisieren in neuen Strukturtypen. Diese Befunde werden auf der Basis der Kristallstruktur von ZnSeO3 · H2O (P21/n, a = 477,9(1), b = 1319,4(5), c = 570,1(1) pm, β = 90,84(2)°, Z = 4, Dx = 3,886 g · cm-3, R = 0,035 für 722 Reflexe mit I 〉 2σ1) und der lokalen Pseudosymmetrie ihrer Bausteine (Schichten ∞2[ZnSeO3 · H2O] aus vierfach eckenverknüpften ZnO6-Oktaedern, SeO32--Anionen und H2O-Moleküle) diskutiert.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-5028
    Keywords: carrot ; cell wall ; suspension culture ; secreted glycoprotein ; root ; nodulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A 47 kDa glycoprotein, termed EP4, was purified from carrot cell suspension culture medium. An antiserum raised against EP4 also recognized a protein of 45 kDa that was ionically bound to the cell wall. EP4 was detected in culture media from both embryogenic and non-embryogenic cell lines and was found to be secreted by a specific subset of non-embryogenic cells. Secretion of the 47 kDa glycoprotein by embryogenic cells was not evident. The 45 kDa cell wall-bound EP4 protein was specific for non-embryogenic cells and was shown by immunolocalization to occur in the walls of clustered cells, with the highest levels in the walls separating adjacent cells. In seedlings, EP4 proteins were mainly found in roots. EP4 cDNA was cloned by screening a cDNA library with an oligonucleotide derived from an EP4 peptide sequence. The EP4 cDNA sequence was found to be 55% homologous to ENOD8, an early nodulin gene from alfalfa.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-5028
    Keywords: complementation ; expression ; co-suppression ; granule-bound starch synthase ; Solanum tubersoum L. ; transgenic inheritance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The wild-type gene encoding granule-bound starch synthase (GBSS) is capable of both complementing the amylosefree (amf) potato mutant and inhibiting the endogenous GBSS gene expression in wild-type potato. Co-suppression of the endogenous GBSS gene, easily visualised by staining the starch with iodine, occurred when the full-size GBSS sequence (genomic), GBSS cDNA or even the mutant amf allele were introduced into the wild-type potato. Conversely, introduction of the GBSS promoter sequence alone, did not result in co-suppression in the 80 analysed transformants. Neither the orientation of the GBSS gene with respect to kanamycin resistance nor the presence of an enhancer influenced the frequency of plants showing a co-suppression phenotype. After crossing a partially complemented amf mutant with a homozygous wild-type plant, the F1 offspring segregated into plant phenotypes with normal and decreased expression of the GBSS gene. This decreased expression correlated with the presence of a linked block of five T-DNA inserts which was previously shown to be correlated with partial complementation of the amf mutant. This crossing experiment indicates that co-suppression can cause inhibition of gene expression of both inserted and endogenous wild-type GBSS genes. The frequency of partially complemented amf plants was equal to the frequency of co-suppressed wild types when a construct, with an enhancer in front of the GBSS promoter, was used (pWAM 101E). This might suggest that partial complementation of the amf genotype caused by unstable expression of the transgene can be overcome by inserting an enhancer in front of the GBSS promoter.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1573-5028
    Keywords: Genetic engineering ; KDEL retention signal ; signal peptide ; single-chain antibody ; targeting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of subcellular localization on single-chain antibody (scFv) expression levels in transgenic tobacco was evaluated using an scFv construct of a model antibody possessing different targeting signals. For translocation into the secretory pathway a secretory signal sequence preceded the scFv gene (scFv-S). For cytosolic expression the scFv antibody gene lacked such a signal sequence (scFv-C). Also, both constructs were provided with the endoplasmic reticulum (ER) retention signal KDEL (scFv-SK and scFv-CK, respectively). The expression of the different scFv constructs in transgenic tobacco plants was controlled by a CaMV 35S promoter with double enhancer. The scFv-S and scFv-SK antibody genes reached expression levels of 0.01% and 1% of the total soluble protein, respectively. Surprisingly, scFv-CK transformants showed considerable expression of up to 0.2% whereas scFv-C transformants did not show any accumulation of the scFv antibody. The differences in protein expression levels could not be explained by the steady-state levels of the mRNAs. Transient expression assays with leaf protoplasts confirmed these expression levels observed in transgenic plants, although the expression level of the scFv-S construct was higher. Furthermore, these assays showed that both the secretory signal and the ER retention signal were recognized in the plant cells. The scFv-CK protein was located intracellularly, presumably in the cytosol. The increase in scFv protein stability in the presence of the KDEL retention signal is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Electrodes for air-driven PEMFCs for transport applications have been developed. The structure of the electrodes has been specifically adapted to run with air as oxidant under near atmospheric pressure; such electrodes can be manufactured using conventional industrial methods and be easily scaled up. The technology has been demonstrated on a 50 cm2 electrode area, assembled together with a Nafion® 117 membrane. Electrodes with different platinum loading, namely 0.4 and 0.2 mg Pt cm−2, have been the subject of long duration tests which show a slow degradation of the cell performance. With air as oxidant at 180 kPa absolute pressure, 80°C as cell temperature and Nafion® 117 as membrane, a power density of 350 mW cm−2 has been obtained.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Cellular automata provide the key to a dynamic modelling and simulation framework that integrates socio-economic with environmental models, and that operates at both micro and macro geographical scales. An application to the problem of forecasting the effect of climate change on a small island state suggests that such modelling techniques could help planners and policy makers design more effective policies — policies better tuned both to specific local needs and to overall socio-economic and environmental constraints.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0044-2313
    Keywords: Phosphorus sulfides ; 31P NMR spectroscopy ; phosphorus sulfur melts ; tetra phosphorus hexasulfide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Molecular Composition of Solidified Phosphorus-Sulfur Melts and the Crystal Structure of β-P4S6Phosphorus sulfur melts were annealed for one week at 673 K and then quenched in ice water. The solids were dissolved in CS2 and the concentrations of phosphorus sulfides were determined by 31P NMR spectroscopy. Samples containing between 44 and 70 mol% sulfur dissolved completely in CS2. Between 0 and 42 mol% remains an insoluble residue of red phosphorus. Above 72 mol% it consisted of sulfur chains linked by phosphorus atoms. The solutions contained mainly the congruently melting compounds P4S3, P4S7, and P4S10 having maximum concentrations at their stoichiometric compositions. Other compounds P4Sn (n = 4-9) which decompose on heating, according to the phase diagram, were also found in surprisingly high concentrations. One of these was β-P4S6 which crystallizes in the monoclinic space group P21/c with the lattice parameters a = 702.4(2), b = 1 205.6(2), c = 1 148.9(6) pm and β = 103.4(2)°.Reaction of white phosphorus with sulfur was also investigated. In contrast to the results of previous authors, who described the system P4-S8 below 373 K as eutectic, we found that the elements reacted below this temperature.
    Notes: Phosphor-Schwefel-Schmelzen wurden eine Woche bei 673 K getempert und anschließend in Eiswasser abgeschreckt, dann in CS2 gelöst und die Konzentration der Phosphorsulfide mit Hilfe der 31P-NMR-Spektroskopie bestimmt. Proben mit Zusammensetzungen zwischen 44 und 70 Mol-% Schwefel lösten sich vollständig auf. Zwischen 0 und 42 Mol-% Schwefel traten als unlöslicher Rückstand roter Phosphor, oberhalb von 72 Mol-% Schwefel über Phosphoratome vernetzte Schwefelketten auf. Die löslichen Bestandteile waren hauptsächlich die kongruent schmelzenden Verbindungen P4S3, P4S7 und P4S10. Die maximalen Konzentrationen lagen bei den jeweiligen stöchiometrischen Zusammensetzungen. Andere P4Sn (n = 4-9) Verbindungen, deren Molekülkristalle sich beim Erwärmen peritektisch oder peritektoid zersetzen, wurden ebenfalls mit höheren Konzentrationen gefunden, dazu gehörte β-P4S6, das in der monoklinen Raumgruppe P21/c mit den Gitterkonstanten a = 702,4(2), b = 1 205,6(2), c = 1 148,9(6) pm und β = 103,4(2)° kristallisiert.Die Reaktion von weißem Phosphor mit Schwefel wurde ebenfalls untersucht. Im Gegensatz zu Angaben anderer Autoren, die das P4-S8-System unterhalb von 373 K als einfach eutektisch beschreiben, wurden in diesem Temperaturbereich Reaktionen zwischen den Komponenten beobachtet.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0044-2313
    Keywords: Hydrogen selenites ; crystal structure ; IR ; Raman heating ; thermal analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Hydrates M(HSeO3)2 · 4H2O (M = Mg, Co, Ni, Zn) - Crystal Structures, IR, Raman, and Thermoanalytical InvestigationsFrom aqueous solutions of M(HSeO3)2 single crystals of Mg(HSeO3)2 · 4H2O and of the hitherto unknown compounds Co(HSeO3)2 · 4H2O, Ni(HSeO3)2 · 4H2O and Zn(HSeO3)2 · 4H2O could be obtained. The crystal structures, X-ray powder, IR, Raman and thermoanalytical (DTA, TG, Raman heating) data are presented and discussed. The crystal data of the isotypic compounds are: monoclinic, space group C2/c, Z = 4, Mg: a = 1 464.6(2), b = 755.3(1), c = 1 099.9(1) pm, β = 126.59(1)°, V = 0.9769(1) nm3, Co: a = 1 462.5(2), b = 756.5(2), c = 1 102.2(2) pm, β = 126.53(1)°, V = 0.9798(2) nm3, Ni: a = 1 452.2(2), b = 751.0(1), c = 1 091.5(1) pm, β = 126.28(1)°, V = 0.9595(1) nm3, Zn: a = 1 468.3(2), b = 755.8(1), c = 1 103.1(1) pm, β = 126.79(1)°, V = 0.9804(2) nm3. The crystal structures consist of hexagonal packed [M(HSeO3)2 · 2H2O]n chains of [MO4(H2O)2] octahedra linked by Se atoms. They contain trigonal pyramidal SeO2OH-ions with “free” hydroxyl groups and also “free” molecules of water of crystallization. The hydroxyl groups build strong H-bonds (O—H … O distances: 265-268 pm). The IR spectra show AB doublett bands in the OH stretching mode region of the hydroxyl groups. The water molecules of crystallization are linked to planar (H2O)4 tetramers by H-bonds with unusually short O—H … O bond distances of 271-273 pm. DTA and TG measurements indicate that thermal decomposition results in the direct formation of the respective diselenite MSe2O5. Raman heating measurements show under quasi static conditions the intermediate formation of the anhydrous hydrogen selenites.
    Notes: Aus M(HSeO3)2-Lösungen konnten erstmals Einkristalle von Mg(HSeO3)2 · 4H2O sowie die bisher nicht bekannten Verbindungen Co(HSeO3)2 · 4H2O, Ni(HSeO3)2 · 4H2O und Zn(HSeO3)2 · 4H2O erhalten werden. Die Kristallstrukturen, Röntgenpulverdaten, IR- und Raman-Spektren sowie die Ergebnisse thermoanalytischer (DTA, TG, Raman-Heizaufnahmen) Untersuchungen werden mitgeteilt und diskutiert. Die Kristalldaten der isotypen Verbindungen sind: monoklin, Raumgruppe C2/c, Z = 4, Mg: a = 1 464,6(2), b = 755,3(1), c = 1 099,9(1) pm, β = 126,59(1)°, V = 0,9769(1) nm3, Co: a = 1 462,5(2), b = 756,5(2), c = 1 102,2(2) pm, β = 126,53(1)°, V = 0,9798(2) nm3, Ni: a = 1 452,2(2), b = 751,0(1), c = 1 091,5(1) pm, β = 126,28(1)°, V = 0,9595(1) nm3, Zn: a = 1 468,3(2), b = 755,8(1), c = 1 103,1(1) pm, β = 126,79(1)°, V = 0,9804(2) nm3. Die Kristallstrukturen bestehen aus hexagonal gepackten [M(HSeO3)2 · 2H2O]n-Ketten Se-verbrückter [MO4(H2O)2]-Oktaeder. Sie enthalten trigonal pyramidale SeO2OH--Ionen mit „freien“ Hydroxylgruppen und „freie“ Kristallwassermoleküle. Die Hydroxylgruppen bilden starke H-Brücken (O—H … O-Abstände: 265-268 pm). Die IR-Spektren zeigen im Bereich der OH-Streckschwingungen der Hydroxylgruppen AB-Doublett-Banden. Die Kristallwassermoleküle sind zu planaren (H2O)4-Tetrameren mit ungewöhnlich kurzen O—H … Ow-Abständen (271 - 273 pm) H-verbrückt. Die thermische Zersetzung führt nach DTA- und TG-Messungen direkt zum jeweiligen Diselenit MSe2O5. Mittels Raman-Heizaufnahmen unter Quasi-Gleichgewichtsbedingungen konnte erstmals die intermediäre Bildung wasserfreier Hydrogenselenite beobachtet werden.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...