Search Results - (Author, Cooperation:E. Post)
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1Latest Papers from Table of Contents or Articles in PressStaff View
Publication Date: 2013-10-11Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: Animals ; *Computer Simulation ; *Global WarmingPublished by: -
2Latest Papers from Table of Contents or Articles in PressE. Post ; U. S. Bhatt ; C. M. Bitz ; J. F. Brodie ; T. L. Fulton ; M. Hebblewhite ; J. Kerby ; S. J. Kutz ; I. Stirling ; D. A. Walker
American Association for the Advancement of Science (AAAS)
Published 2013Staff ViewPublication Date: 2013-08-03Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Animals ; Aquatic Organisms ; Arctic Regions ; *Climate Change ; Humans ; *Ice Cover ; Invertebrates ; Plant Development ; *Seawater ; VertebratesPublished by: -
3Latest Papers from Table of Contents or Articles in PressV. E. Post ; J. Groen ; H. Kooi ; M. Person ; S. Ge ; W. M. Edmunds
Nature Publishing Group (NPG)
Published 2013Staff ViewPublication Date: 2013-12-07Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: *Geology ; *Groundwater ; Oceans and Seas ; SalinityPublished by: -
4Articles: DFG German National LicensesCooper, E. B. ; Post, E. R. ; Griffith, S. ; Levitan, J. ; Manalis, S. R.
Woodbury, NY : American Institute of Physics (AIP)
Published 2000Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We demonstrate a promising type of microfabricated accelerometer that is based on the optical interferometer. The interferometer consists of surface-micromachined interdigital fingers that are alternately attached to a proof mass and support substrate. Illuminating the fingers with coherent light generates a series of diffracted optical beams. Subangstrom displacements between the proof mass and frame are detected by measuring the intensity of a diffracted beam. The structure is fabricated with a two-mask silicon process and detected with a standard laser diode and photodetector. We estimate that the minimum detectable acceleration is six orders of magnitude below the acceleration of gravity, i.e., 2 μg/Hz in a 1 Hz bandwidth centered at 650 Hz. © 2000 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesStaff View
ISSN: 0005-2728Keywords: (R. rubrum) ; Developmental stage ; Light reaction ; Photosynthetic apparatus ; Proton extrusionSource: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: BiologyChemistry and PharmacologyMedicinePhysicsType of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesStaff View
ISSN: 0022-0248Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyGeosciencesPhysicsType of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesStaff View
ISSN: 1574-6968Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: BiologyType of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesStaff View
ISSN: 0040-6031Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyType of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesSchuurman, R. K. B. ; Mensink, E. J. B. M. ; Sandkuyl, L. A. ; Post, E. D. M. ; Velzen-Blad, H.
Springer
Published 1988Staff ViewISSN: 1432-1076Keywords: X-linked agammaglobulinaemia ; Restriction fragment length polymorphism ; Early diagnosis ; Carrier detectionSource: Springer Online Journal Archives 1860-2000Topics: MedicineNotes: Abstract The genetic transmission of X-linked agammaglobulinaemia (XLA) can be determined with high probability using closely linked DNA restriction fragment length polymorphisms (RFLP's). In a family known to be at risk for XLA in male offspring, RFLP analysis demonstrated that the mother was an XLA carrier and her newborn son was affected. The infant developed immunological deficiencies a few months later, confirming the diagnosis. RFLP analysis provides a method for carrier detection, prenatal diagnosis and presymptomatic diagnosis of XLA, which plays a significant role in prevention of the disease.Type of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesStaff View
ISSN: 1432-072XKeywords: Azotobacter vinelandii ; Continuous culture ; Membranes ; Respiratory reactionsSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract Dinitrogen fixing cells of Azotobacter vinelandii increase the ratio of intracytoplasmic to cytoplasmic membranes surface area linearly by a factor of six when growing in an oxygen controlled chemostat from about 1% to 100% air saturation of the culture medium (Post et al. 1982). In spite of this, cells grown at 1%, 45%, and 80% air saturation exhibited only a single membrane fraction with a buoyant density of ϱ20 = 1.176 g cm−3 after equilibrium sucrose density gradient centrifugation. (Cell wall exhibited a density of ϱ20 = 1.23 g cm−3.) Total cell membrane preparations were employed to study the proportion of respiratory reactions with cells grown at various oxygen concentrations. Maximum activities as well as substrate affinities of NADH, NADPH, and malate dehydrogenases increased from about 1% to 30% air saturation and stayed almost constant at higher oxygen concentrations. Activities of the three dehydrogenases changed largely in parallel. Essentially the same dependency on oxygen concentration was measured with the rate limiting step of the terminal respiratory pathway. Consequently, the ratio of the dehydrogenase activities to the activity of the rate limiting step of the terminal pathway stayed constant. The data suggest that intracytoplasmic and cytoplasmic membranes do not differ with respect to respiratory activities. It is discussed that both types of membranes represent differently localized parts of an otherwise identical membrane system.Type of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesStaff View
ISSN: 1432-072XKeywords: Azotobacter vinelandii ; Continuous culture ; Control of membrane formation ; Cell sizeSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract Membrane development as a response to growth at different oxygen tensions (from about 1% to 100% saturation of the medium with air) was determined inAzotobacter vinelandii strain OP. The organisms were grown in a carbonlimited chemostat either on atmospheric nitrogen or on ammonium as nitrogen sources. Both types of cultures increased not only the number of intracytoplasmic membrane vesicles per cell but also the cell volume with aeration. As the ratio of length per width stayed largely constant increases of volume resulted in decreases of the cell surface area, representing the surface area of the peripheral cytoplasmic membrane, per cell volume. While in nitrogen-fixing cells the proportion of intracytoplasmic membrane surface area per cytoplasmic membrane surface area increased from 1:2 to 3:1 the ratio stayed almost constant in ammonium-assimilating cells. The data suggest that oxygen controls changes in the ratio of intracytoplasmic to cytoplasmic membrane surface areas only under conditions of nitrogen fixation.Type of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesStaff View
ISSN: 1432-072XKeywords: Azotobacter vinelandii ; Continuous culture ; Oxygen control ; Nitrogen fixation ; Respiratory protectionSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract Azotobacter vinelandii strain OP was grown in continuous culture at various dissolved oxygen concentrations of air (100% air saturation of the medium=225 ±14 μM O2). Sucrose was added as carbon source and either dinitrogen or ammonia as nitrogen sources. Irrespective of the nitrogen source steady state cultures showed the following general responses with dissolved oxygen concentrations increasing from about 1% to 30% air saturation: (i) cell protein levels, (ii) the amount of cell protein formed per sucrose consumed as well as (iii) nitrogenase activity decreased by at least a factor of two while (iv) cellular respiration increased. At higher oxygen concentrations the parameters changed only slightly, if at all. Increasing the sucrose concentration in the inflowing medium (s R) from 3 g/l to 15 g/l increased the total level of cellular respiration with nitrogen-fixing cultures but was more pronounced with ammonium-assimilating cultures. With nitrogen-fixing cultures cell protein levels increased five-fold while the ratio of protein formed per sucrose consumed as well as cellular nitrogenase activity remained unaffected. With ammonium-assimilating cultures the cell protein level was only doubled and the level of cell protein formed per sucrose consumed was decreased at the higher s R. Increasing the dilution rate at a constant oxygen concentration of 45% air saturation resulted in an almost parallel increase of both cellular respiratory and nitrogenase activity at low and moderate dilution rates. At high dilution rates nitrogenase activity increased steeply over the respiratory activity. Nitrogen-fixing cultures adapted to various oxygen concentrations were subjected to oxygen stress by increasing the oxygen concentration for 7 min. In all cases, this resulted in a complete inhibition (‘switch-off’) of nitrogenase activity. Upon restoration of the original oxygen concentration nitrogenase activity returned to a decreased level. The discussion arrives at the conclusion that some of the results are incompatible with the concept of respiratory protection of nitrogenase.Type of Medium: Electronic ResourceURL: -
13Articles: DFG German National LicensesStaff View
ISSN: 1432-072XKeywords: Azotobacter vinelandii ; Nitrogenase ; Glutamine synthetase ; Glutamate synthase ; Intracellular localization of enzymes ; ChemostatSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Summary Azotobacter vinelandii was grown in oxygen-controlled continuous cultures under conditions of dinitrogen fixation. Different oxygen concentrations were adjusted with air. Cell-free extracts were employed to study the oxygen dependency of the intracellular distribution and activity of the following enzymes: nitrogenase, glutamine synthetase and glutamate synthase. Nitrogenase was localized exclusively in the soluble fraction. Its activity increased steeply when the oxygen concentration employed in growing the organism decreased from about 30% close to 0% air saturation. Glutamine synthetase was identified exclusively as a soluble enzyme. The degree of adenylylation of the enzyme increased from about one to about four parallel to nitrogenase activity when the oxygen concentration in the culture was lowered. Glutamate synthase was detected in both a soluble and a membrane-bound form. The sum of specific activities of both forms stayed constant irrespective of changes in the oxygen concentration. However, with increasing oxygen concentration, the proportion of the membrane-bound form increased up to two-thirds of the total activity.Type of Medium: Electronic ResourceURL: -
14Articles: DFG German National LicensesStaff View
ISSN: 1572-8943Keywords: ceramics ; metals ; polymers ; recycling ; TG/DSC/DTA-QMSSource: Springer Online Journal Archives 1860-2000Topics: Chemistry and PharmacologyNotes: Abstract A mass spectrometer coupling system for simultaneous TG/DSC/DTA-QMS measurements will be introduced that is capable of operation at temperatures up to 2000°C. The coupling is maintained at a temperature very close to that of the sample, minimizing condensation, and features an extremely short gas flow path. The efficiency of this coupling system will be demonstrated through examples from the area of polymers, ceramics, metallurgy and recycling.Type of Medium: Electronic ResourceURL: -
15Articles: DFG German National LicensesStaff View
ISSN: 1572-8943Keywords: curing kinetics ; DMA ; electronic scrap ; epoxy resin ; TG-MS ; thermal expansionSource: Springer Online Journal Archives 1860-2000Topics: Chemistry and PharmacologyNotes: Abstract With the aid of thermal analysis, epoxy (EP) resins have been characterized from the curing of the components all the way to disposal. The methods employed for the investigations were DSC, TMA, DMA, TG and TG-QMS. The experimental results obtained will be used here to demonstrate the typical possibilities offered by these methods for characterization of an epoxy resin from ‘cradle to grave’.Type of Medium: Electronic ResourceURL: -
16Articles: DFG German National LicensesStaff View
ISSN: 1572-8943Keywords: decomposition gases containing heavy metals ; environmental protection ; mass spectrometer ; thermal analysis ; thermal decomposition of plastics productsSource: Springer Online Journal Archives 1860-2000Topics: Chemistry and PharmacologyNotes: Abstract The decomposition reactions of polystyrene, phenolic resin and a protective undercoating material for automobiles which contains PVC were tested using a new type of thermal analysis — mass spectrometry coupling system for measurements to 1500Type of Medium: Electronic ResourceURL: -
17Articles: DFG German National LicensesPyriki, C. ; Heiduschka, A. ; Post, E. ; Waser, E. ; Stähli, Marta ; Wenusch, A. ; Schaarschmidt, A. ; Hofmeier, H. ; Nowak, P. ; Lehmann, K. B. ; Gawrilow, N. J. ; Koperina, A. W. ; Bodnár, J. ; Barta, L. ; Fodor, A. ; Reifenberg, A. ; Faitelowitz, A. ; Rundshagen, H. ; Nagy, V. L.
Springer
Published 1933Staff ViewISSN: 1618-2650Source: Springer Online Journal Archives 1860-2000Topics: Chemistry and PharmacologyType of Medium: Electronic ResourceURL: -
18Articles: DFG German National LicensesStaff View
ISSN: 1572-9516Source: Springer Online Journal Archives 1860-2000Topics: PhysicsNotes: Abstract A comparative study is made of the eigenvalue problems of electromagnetics and quantum mechanics, with special reference to the operations of spatial inversionP and time inversionT. Electromagnetics, which permits closer agreement with the dictates of relativity (when the latter is extended toP andT), exhibits characteristic differences with respect to quantum mechanics. An evaluation of these distinctions is presented against the backdrop of a choice between absolute scalar action and charge versus pseudoscalar action and charge.Type of Medium: Electronic ResourceURL: -
19Articles: DFG German National LicensesStaff View
ISSN: 1572-9516Source: Springer Online Journal Archives 1860-2000Topics: PhysicsNotes: Abstract The questions of observational error and ambiguity of interpretation that have been raised in connection with the reported observation of a magnetic monopole have precipitated a situation calling for some further insight into the pairing principles of nature. A basic distinction relates to whether or not a pair is “ordered” (e.g., sexual pair) or without a priori order (e.g., mirror pair). It is shown that the polarity of electric charge is to be regarded as an example of pairing without an intrinsic a priori order. It then follows that “action” also exhibits a pairing without a priori order. The relation ofPC andTC to unordered and ordered pairing is discussed, with neutral kaon pairing as a striking example of ordered pairing. The pairing of magnetic charge, if it exists, becomes an ordered pairing!Type of Medium: Electronic ResourceURL: -
20Articles: DFG German National LicensesStaff View
ISSN: 1572-9516Source: Springer Online Journal Archives 1860-2000Topics: PhysicsNotes: Abstract Previous statements concerning the reduction of possible parity and time reversal choices for electromagnetic quantities are amplified for the sake of clearer understanding.Type of Medium: Electronic ResourceURL: