Library

X
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
    Electronic Resource
    Electronic Resource
    Structure-odour-activity relationships of alkylpyrazines (1999)
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 208 (1999), S. 308-316 
    Details
    ISSN: 1431-4630
    Keywords: Key words Pyrazine ; Odour threshold ; Structure ; Molecular modelling ; Theoretical receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  The odour thresholds (i.e. the lowest concentration at which an odour can be detected) of 80 alkylpyrazines, most of them synthesized, were determined by gas chromatography-olfactometry. Trimethylpyrazine (1) had the lowest threshold (50 ng/l air) amongst mono-, di-, tri- and tetramethylpyrazine. Substitution of the methyl group in position 2 of 1 by an ethyl group yielded 2-ethyl-3,5-dimethylpyrazine (2) showing a 4500-fold lower odour threshold than 1. The thresholds of 2-ethenyl-3,5-dimethylpyrazine (3), 2,3-diethyl-5-methylpyrazine (4) and 2-ethenyl-3-ethyl-5-methylpyrazine (5) were as low as that of 2. The threshold of 3-ethenyl-2-ethyl-5-methylpyrazine was 8000 times higher than that of 5, indicating that an ethenyl group was only tolerated in position 2, but not in position 3. A further increase in the odour threshold was found when the ethenyl or the ethyl group was located in position 5. Substitution of the ethyl group of 2 by a (Z)-1-propenyl group increased the threshold only by a factor of 5, whereas the (E)-isomer and the 2-propenyl group enhanced the threshold by factors of 160 and 27000, respectively. Also a propyl, butyl, pentyl, isobutyl or hexyl group in position 2 of 2 was too bulky, and in these molecules the odour threshold was at least 2200 times higher than that of 2. The geometrical structure of a theoretical receptor was obtained by superimposing the minimized structures of pyrazines with low thresholds (Chem-X force-field minimization). Sterically forbidden regions in the resulting model were found by superimposing pyrazines with high thresholds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050422
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Autoantibodies to the islet antigen ICA 69 occur in IDDM and in rheumatoid arthritis (1995)
    Springer
    Diabetologia 38 (1995), S. 351-355 
    Details
    ISSN: 1432-0428
    Keywords: Key words ICA 69 ; insulin-dependent diabetes mellitus; rheumatoid arthritis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Islet cell antigen (ICA) 69 is a newly-recognized islet cell antigen to which autoantibodies have been observed in prediabetic relatives of patients with insulin-dependent-diabetes mellitus (IDDM). Here we extend the earlier analysis of ICA 69 antibodies to patients with recent-onset IDDM and to patients with other immune-mediated diseases. ICA 69 antibodies were determined by Western blot using an affinity purified recombinant fusion protein of ICA 69 and maltose binding protein. ICA 69 antibody quantities were determined as titres using a titration curve of a standard serum as reference. Mean logarithmic ICA 69 antibody titres were 3.4 (± 1.4) in 99 patients with acute IDDM compared to 2.8 (± 0.9) in 49 healthy blood donors (p 〈 0.001). A higher mean ICA 69 antibody titre of 4.1 (± 0.8) was observed in 16 patients with rheumatoid arthritis in comparison to acute IDDM (p 〈 0.01) and healthy control subjects (p 〈 0.001). The percentage of sera with ICA 69 antibody titres above the 2 SD level of normal subjects was 21 % in IDDM, 31 % in rheumatoid arthritis and 6 % in healthy blood donors. None of the patients with autoimmune thyroid disease (n = 20), inflammatory bowel disease (n = 9) or multiple sclerosis (n = 7) had elevated ICA 69 antibodies. In IDDM, presence of ICA 69 antibodies persisted and the titre remained the same over 18 months of follow-up. The relationship of ICA 69 antibodies to islet cell antibodies (ICA) or insulin autoantibodies (IAA) was tested. The production of ICA 69 antibodies was not associated in diabetic patients with the presence of any of the two other autoantibodies. In conclusion, this study describes ICA 69 antibodies in acute IDDM and finds them to be independent of other islet autoantibodies. In addition ICA 69 is a target of humoural autoimmunity not only in IDDM but also in rheumatoid arthritis. [Diabetologia (1995) 38: 351–355]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400641
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Autoantibodies to the islet antigen ICA 69 occur in IDDM and in rheumatoid arthritis (1995)
    Springer
    Diabetologia 38 (1995), S. 351-355 
    Details
    ISSN: 1432-0428
    Keywords: ICA 69 ; insulin-dependent diabetes mellitus ; rheumatoid arthritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Islet cell antigen (ICA) 69 is a newly-recognized islet cell antigen to which autoantibodies have been observed in prediabetic relatives of patients with insulin-dependent-diabetes mellitus (IDDM). Here we extend the earlier analysis of ICA 69 antibodies to patients with recent-onset IDDM and to patients with other immune-mediated diseases. ICA 69 antibodies were determined by Western blot using an affinity purified recombinant fusion protein of ICA 69 and maltose binding protein. ICA 69 antibody quantities were determined as titres using a titration curve of a standard serum as reference. Mean logarithmic ICA 69 antibody titres were 3.4 (±1.4) in 99 patients with acute IDDM compared to 2.8 (±0.9) in 49 healthy blood donors (p〈0.001). A higher mean ICA 69 antibody titre of 4.1 (±0.8) was observed in 16 patients with rheumatoid arthritis in comparison to acute IDDM (p〈0.01) and healthy control subjects (p〈0.001). The percentage of sera with ICA 69 antibody titres above the 2 SD level of normal subjects was 21% in IDDM, 31% in rheumatoid arthritis and 6% in healthy blood donors. None of the patients with autoimmune thyroid disease (n=20), inflammatory bowel disease (n=9) or multiple sclerosis (n=7) had elevated ICA 69 antibodies. In IDDM, presence of ICA 69 antibodies persisted and the titre remained the same over 18 months of follow-up. The relationship of ICA 69 antibodies to islet cell antibodies (ICA) or insulin autoantibodies (IAA) was tested. The production of ICA 69 antibodies was not associated in diabetic patients with the presence of any of the two other autoantibodies. In conclusion, this study describes ICA 69 antibodies in acute IDDM and finds them to be independent of other islet autoantibodies. In addition ICA 69 is a target of humoural autoimmunity not only in IDDM but also in rheumatoid arthritis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400641
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Observation of the plasma channel dynamics and Coulomb explosion in the interaction of a high-intensity laser pulse with a He gas jet (1997)
    Springer
    JETP letters 66 (1997), S. 828-834 
    Details
    ISSN: 1090-6487
    Keywords: 52.50.Jm ; 52.20.Hv ; 42.65.Jx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report the first interferometric observations of the dynamics of electron-ion cavitation of relativistically self-focused intense 4 TW, 400 fs laser pulse in a He gas jet. The electron density in a channel 1 mm long and 30 μm in diameter drops by a factor of approximately 10 from the maximum value of ∼8×1019 cm−3. A high radial velocity of the plasma expansion, ∼3.8×108 cm/s, corresponding to an ion energy of about 300 keV, is observed. The total energy of fast ions is estimated to be 6% of the laser pulse energy. The high-velocity radial plasma expulsion is explained by a charge separation due to the strong ponderomotive force. This experiment demonstrates a new possibility for direct transmission of a significant portion of the energy of a laser pulse to ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567605
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    A FRAMEWORK FOR PHOSPHORUS TRANSPORT MODELING IN THE LAKE OKEECHOBEE WATERSHED (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 32 (1996), S. 0 
    Details
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : A modeling framework was developed to determine phosphorus loadings to Lake Okeechobee from watersheds located north of the lake. This framework consists of the land-based model CREAMS-WT, the in-stream transport model QUAL2E, and an interface procedure to format the land-based model output for use by the in-stream model. QUAL2E hydraulics and water quality routines were modified to account for flow routing and phosphorus retention in both wetlands and stream channels. Phosphorus loadings obtained from previous applications of CREAMS-WT were used by QUAL2E, and calibration and verification showed that QUAL2E accurately simulated seasonal and annual phosphorus loadings from a watershed. Sensitivity and uncertainty analyses indicated that the accuracy of monthly loadings can be improved by using better estimates of in-stream phosphorus decay rates, ground water phosphorus concentrations, and runoff phosphorus concentrations as input to QUAL2E.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-1688.1996.tb03434.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Analysis of the desmoplakin gene reveals striking conservation with other members of the plakin family of cytolinkers (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Experimental dermatology 8 (1999), S. 0 
    Details
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Members of the plakin family of cytolinker proteins integrate filaments into cellula networks and anchor these networks to the plasma membrane. Their importance is supported by the existence of cell and tissue fragility disorders caused by mutations in certain family members. In this study, the human gene encoding desmoplakin (DSP) was characterized and its structure compared with the related family members: plectin, bullous pemphigoid antigen 1 (BPAG1), envoplakin (EVPL) and periplakin (PPL). Sequence analysis of genomic clones was carried out in combination with a PCR-based strategy to define intron-exon border. DSP was mapped using the GB4 radiation hybrid mapping panel to the interval between markers D6S296 and AFM043Xf2, correponding to cytogenetic band 6p24. In addition, the murine gene (DSP) was mapped to mouse chromosome 13 by interspecific backcross mapping. DSP encompasses 45 kb organized into 24 exons and 23 introns, and the pattern of intron-exon borders bears a striking resemblance to other member of the plakin family. Notable features include the fact that a single large exon encodes the entire C-termius of each gene. In contrast, the N-termini comprise numerous smaller exons with conservation of many genses will facilitate their further evaluation as targets of genetic disorders and provide insights into the evolutionary relationships among molecules in this emerging gene family.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0625.1999.tb00304.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The ORF YBL042 of Saccharomyces cerevisiae encodes a uridine permease (1998)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 159 (1998), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The purpose of this work was to identify the function of an open reading frame called YBL042, found during the systematic sequencing of Saccharomyces cerevisiae's chromosome II. The YBL042 gene product shows 70% similarity with the uracil permease and the allantoin permease encoded by FUR4 and DAL4, respectively. The mutation constructed by disruption of this ORF is allelic to the FUI1 gene previously described as encoding the uridine permease but not cloned yet. A strain carrying the disrupted allele and a fui1 mutant exhibit the same phenotype as they do not grow on a medium containing uridine as the sole source of pyrimidines and as they are resistant to 10−3 M 5-fluorouridine (5FUI), a toxic analog of uridine. Even though the FUI1 gene has a multicopy suppressor effect on uracil transport, its product does not seem to be involved in this transport, in contrast to the FUR4 gene product which is involved in uridine transport. Moreover, the FUI1 gene product does not play any role in allantoin transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1998.tb12843.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Detailed dynamics of electron beams self-trapped and accelerated in a self-modulated laser wakefield (1999)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 6 (1999), S. 4739-4749 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electron beam generated in a self-modulated laser-wakefield accelerator is characterized in detail. A transverse normalized emittance of 0.06 π mm mrad, the lowest ever for an electron injector, was measured for 2 MeV electrons. The electron beam was observed to have a multicomponent beam profile and energy distribution. The latter also undergoes discrete transitions as the laser power or plasma density is varied. In addition, dark spots that form regular modes were observed in the electron beam profile. These features are explained by analysis and test particle simulations of electron dynamics during acceleration in a three-dimensional plasma wakefield. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.873761
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Proton recoil detector of fusion neutrons using natural diamond : Proceedings of the eleventh topical conference on high temperature plasma diagnostics (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 624-627 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Diamond, with its high radiation damage resistance, is an attractive alternative to silicon for neutron measurements in next step fusion experiments. A 200-μm-thick type IIa natural diamond with Ti/Au contacts was tested at the LAMPF-WNR facility by time-of-flight neutron energy identification. The crystal, having a carrier lifetime of up to 1 ns, was arranged in a low-energy-resolution, high-sensitivity proton recoil telescope consisting of a polyethylene radiator and a low-energy-proton Teflon filter. This arrangement is similar to the triton burnup monitor of Croft et al. [Rev. Sci. Instrum. 64, 1418 (1993)], where a silicon photodiode was used as a recoil proton detector. The observed sensitivity for 14 MeV neutrons (DT) is (1.25±0.15)×10−3 counts/neutron. However, a high contribution of neutron-induced events in the diamond, mainly carbon (A=12) recoils, was observed. A one-dimensional calculation for the detector response to carbon recoil and proton deposition is compared to the measurements. Poor energy resolution of the diamond detector precludes pulse height discrimination between direct 2.5 MeV neutrons events and proton events corresponding to 14 MeV neutrons. Therefore, an overall DT/DD neutron sensitivity ratio of only ∼6.5 is achieved. This value is much lower than the ratio of 540 reported by Croft et al. in their silicon (A=28) monitor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147668
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    A technique for efficiently generating bimetallic clusters (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 3010-3013 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Reactivities of bimetallic clusters can be controlled by varying their composition, making them potentially valuable as catalysts and for use in elucidating the reactivities of such subnanoscale surfaces. A dual rod laser vaporization source coupled to a fast flow reactor is developed for the study of bimetallic clusters and their reactions. In order to establish the versatility of the technique, the results of studies are presented in which Nb/Al clusters are formed in two plasmas induced by the second harmonic (532 nm photons) of a single Nd:YAG laser and then detected by a quadrupole mass spectrometer. The beam from the laser is split and then focused onto each rod, allowing the mixing ratio within the cluster to vary by altering the laser fluence on each rod. With a low fluence on the Nb rod and a high fluence on the Al rod, an Al rich cluster distribution is formed, NbAlm〈sup ARRANGE="STAGGER"〉− (m=2–20), and Alm〈sup ARRANGE="STAGGER"〉− (m=5–31). By increasing the fluence on the Nb rod and decreasing the fluence on the Al rod, a Nb rich cluster distribution is formed, NbnAlm〈sup ARRANGE="STAGGER"〉− (n=3–8 and m=1–3),NbnOAlm − (n=3–8 and m=1–5), andNbnO− (n=3–8). Additional characterization is also performed on V/Al clusters. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148058
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...