GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Wiley-Blackwell  (11)
  • Blackwell Science Ltd  (1)
  • The American Association of Immunologists (AAI)  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Geophysical prospecting 45 (1997), S. 0 
    ISSN: 1365-2478
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie , Physik
    Notizen: Migration velocity analysis, a method for determining long wavelength velocity structure, is a critical step in prestack imaging. Solution of this inverse problem is made difficult by a multimodal objective function; a parameter space often vast in extent; and an evaluation procedure for candidate solutions, involving the calculation of depth-migrated image gathers, that can be prohibitively expensive. Recognizing the global nature of the problem, we employ a genetic algorithm (GA) in the search for the optimum velocity model. In order to describe a model efficiently, regions of smooth variation are identified and sparsely parametrized. Region boundaries are obtained via map migration of events picked on the zero-offset time section. Within a region, which may contain several reflectors, separate components describe long and short wavelength variations, eliminating from the parameter space, models with large velocity fluctuations. Vital to the success of the method is rapid model evaluation, achieved by generating image gathers only in the neighbourhood of specific reflectors. Probability of a model, which we seek to maximize, is derived from the flatness of imaged events. Except for an initial interpretation of the zero-offset time section, our method is automatic in that it requires no picking of residual moveout on migrated gathers. Using an example data set from the North Sea, we show that it is feasible to solve for all velocity parameters in the model simultaneously: the method is global in this respect also.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 17 (1982), S. 519-523 
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Both positive ion and negative ion chemical ionization mass spectra of hydroxycarboxylic acids (hydroxyethanoic acid, 3-hydroxypropanic acid, 2-hydroxypropanoic acid and 1-phenyl-1-hydroxyethanoic acid) show intense oligomeric ions when the samples are evaporated into a chemical ionization source. The observation of oligomeric anionic and cationic species is unusual, and the parallel behavior observed between the positive and negative ion mass spectra is striking. These results are explicable in terms of evaporation of oligomers and their dehydration products from the hot probe, although gas phase clustering reactions of singly charged ions are not excluded. Hydrogen bonding and dehydration provide bonding within each cluster. The structures of the ions have been confirmed by recording the collision induced dissociations of individual cluster ions via their mass analyzed ion kinetic energy spectra. Temperature dependence of the chemical ionization mass spectra provides a method for distinguishing hydrogen bonding from covalent bonding and gives further structural information on the cluster ions.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Publikationsdatum: 2011-08-19
    Beschreibung: Six N-substituted [ n ]cyclacene ( n  = 5, 6, 7,…,10) molecules were designed to study the relationship between the structure and first hyperpolarizability. Their static first hyperpolarizabilities ( β 0 ) were obtained by MP2/6-31 + g(d) level. Two interesting relationships between the β 0 value and the structure have been found: (1) The β 0 value increases with the increase of the number n when n is odd: 3155 ([5]cyclacene) 〈 48,905 ([7]cyclacene) 〈 〈 393,444 ([9]cyclacene), and when n is even: 357,620 ([6]cyclacene) 〈 618,608 ([8]cyclacene) 〈 3,513,644 a.u. ([10]cyclacene). (2) The β 0 values (in the range of 357,620 ~ 3,513,644 a.u.) of the N-substituted [ n ]cyclacene (when n is odd) are much larger (in the range of 3155~393,444 a.u.) than that of the N-substituted [ n ]cyclacene (when n is even). Furthermore, their frequency-dependent β (−2ω; ω, ω) and β (−ω; ω, 0) (ω = 0.005, 0.01, and 0.0239 a.u.) were also estimated by Møller–Plesset perturbation/6-31 + g(d) level. Among the frequency-dependent β (ω), [10]cyclacene has the largest β (−ω; ω, 0) and β (−2ω; ω, ω) to be 1.2 × 10 8 (ω = 0.01) and 2.9 × 10 7 a.u. (ω = 0.005 a.u.), which are much larger than the static β 0  = 3.5 × 10 6  a.u. by 34 and 8 times. Our present work may offer a new idea in the design of high-performance tubiform nonlinear optical materials. Copyright © 2011 John Wiley & Sons, Ltd. Because of the structure similar to famous carbon nanotubes, the N-substituted [ n ]cyclacene ( n  = 5, 6…10) are chosen to investigate that how does the relationship between the structure and first hyperpolarizability ( β 0 ).
    Print ISSN: 0894-3230
    Digitale ISSN: 1099-1395
    Thema: Chemie und Pharmazie , Physik
    Publiziert von Wiley-Blackwell
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Publikationsdatum: 2011-06-16
    Beschreibung: Two coordination polymers, namely [Zn(L)Cl] ( 1 ) and [Zn(L) 2 ] ( 2 ) [L = 4-(pyridin-4-ylmethoxy)benzolic acid] were synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction analyses, powder X-ray diffraction, and thermogravimetric analysis. Compounds 1 and 2 have a two-dimensional square-shaped structure (the dimensions are 15.43 × 15.43 Å for 1 and 12.064 × 15.017 Å for 2 ) with (4 4 · 6 2 ) topology. Moreover, compounds 1 and 2 exhibit a 3D supramolecular structure made up by strong π–π interactions from the adjacent layers. Furthermore, compounds 1 and 2 show good fluorescence properties in the solid state at room temperature.
    Print ISSN: 0044-2313
    Digitale ISSN: 1521-3749
    Thema: Chemie und Pharmazie
    Publiziert von Wiley-Blackwell
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Publikationsdatum: 2011-09-14
    Beschreibung: We have synthesized a new complex [Zn(H 2 C 3 PIm)(BTC)H 2 O] n ( 1 ) [H 3 BTC = 1,3,5-benzenetricarboxylic acid, H 2 C 3 PIm = 2,2′-(1,3-propanediyl)-bis(1H-benzimidazole)] and determined its structure (C 26 H 20 N 4 O 7 Zn, Mr = 565.83) using single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic system, space group P 2(1) with a = 8.497(5), b = 16.316(5), c = 9.316(5) Å, β = 104.955(5), V = 1247.8(11) Å 3 , Z = 2, Dc = 1.506 g · cm –3 , μ (Mo- K α ) = 1.038 mm –1 , F (000) = 580, S = 0.755, the final indices are R = 0.0386 and wR = 0.0456 for 3461 reflections with I 〉 2 σ ( I ). In the asymmetric unit of complex 1 , the distorted tetrahedral Zn II ion is bridged by the carboxylic oxygen atoms of the BTC ligand and the nitrogen atoms of the H 2 C 3 PIm ligand. The complex units are linked through BTC ligands into a chiral 2D layer and further connected into a 3D framework by π–π packing interactions between the adjacent H 2 C 3 PIm ligands. The complex exhibits high stablility in air at ambient temperature and strong photoluminescence at room temperature.
    Print ISSN: 0044-2313
    Digitale ISSN: 1521-3749
    Thema: Chemie und Pharmazie
    Publiziert von Wiley-Blackwell
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Publikationsdatum: 2014-07-10
    Beschreibung: ABSTRACT The Standardized Precipitation Index (SPI) has been widely used to monitor the drought status. In the estimation of SPI, an appropriate probability distribution function (APDF) is required to fit precipitation series with different timescales, such as 3-month, 9-month and so on. Then the standard normal distribution function is used to transform the cumulative probability derived from APDF to calculate the SPI value. Obviously, the estimation accuracy of SPI particularly depends on the sample that influences the selection of PDF and parameter estimation. However, the size of the observed sample is usually small, and it cannot perfectly present the statistical property of the population, which usually causes the uncertainty on calculation of SPI and in turn results in the uncertainty of drought assessment. Due to the existence of gap between the estimated SPI and the true SPI, when one obtains the estimation of SPI, it is necessary to know the reliability or uncertainty of the estimated SPI. In this article, a new method based on the Bootstrap method was put forward to analyse the impact of sampling uncertainty on the estimation of SPI and drought assessment. Through repeating samples from the original sample, a large number of Bootstrap samples are constructed, and based on each Bootstrap sample, the corresponding estimation of SPI for the given event can be obtained. Therefore, the sampling distribution of SPI for the given event can also be derived, on which both the point estimation and interval estimation of SPI for the given precipitation event can be provided, and the overall assessment of a drought event could be achieved. The case study shows that, compared with the original SPI calculation method, the proposed method not only provides equivalent assessment results, but also has the capability to assess the impact of sampling uncertainty on the uncertainty of SPI calculation and drought assessment.
    Print ISSN: 0899-8418
    Digitale ISSN: 1097-0088
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley-Blackwell
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Publikationsdatum: 2017-12-18
    Beschreibung: Cancer stem cells (CSCs) play a central role in the development of breast cancer. The canonical Wnt/β-catenin signal pathway is critical for maintaining CSCs characteristics. Diallyl trisulfide (DATS), a natural organosulfur compound from the garlic, exhibits effective antitumor properties. However, the role of DATS in regulating breast CSCs activity and the underlying molecular mechanisms remain obscure. In the present study, we reported that DATS efficiently inhibited the viability of breast CSCs as evidenced by reducing turmorspheres formation, decreasing the expression of breast CSCs markers (CD44, ALDH1A1, Nanog and Oct4), as well as inhibiting proliferation and inducing apoptosis. Furthermore, we showed that DATS suppressed the activity of Wnt/β-catenin pathway, while LiCl-triggered Wnt/β-catenin activation diminished DATS inhibition on breast CSCs. Taken together, our results illustrated that DATS suppressed breast CSCs through inhibiting Wnt/β-catenin pathway activation. These novel findings could provide new insights into the molecular mechanisms of breast CSCs regulation as well as its target intervention and might provide new strategies for preventing and treating breast cancers. This article is protected by copyright. All rights reserved
    Digitale ISSN: 0091-7419
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Publiziert von Wiley-Blackwell
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Publikationsdatum: 2017-03-25
    Beschreibung: Two complexes based on the ligand 1,4-dihydro-2,3-quinoxalinedione, namely [Mn(H 2 L) 2 (H 2 O) 2 ] n ( 1 ) and {[Zn 2 (H 2 L) 2 (tz) 2 ] · 5H 2 O} n ( 2 ) (H 3 L = 2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-carboxylic acid, Htz = 1,2,4-triazole) were hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, as well as single-crystal and powder X-ray diffraction. Complex 1 exhibited a 1D comb-like chain formed by H 2 L – anions linking Mn II ions, whereas complex 2 was a 2D layer-like structure with square-shaped windows and outstretched arms built by combination of H 2 L – and tz – ligands with Zn II ions. The adjacent chains or layers connected with each other by intermolecular hydrogen bonding and π–π stacking to further extend to a 3D supermolecular framework. In addition, the thermal stabilities, luminescence properties, and optical energy gap of 1 and 2 were investigated in detail.
    Print ISSN: 0044-2313
    Digitale ISSN: 1521-3749
    Thema: Chemie und Pharmazie
    Publiziert von Wiley-Blackwell
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Publikationsdatum: 2013-05-22
    Beschreibung: miRNAs have recently been shown to play a significant role in human aging. However, data demonstrating the effects of aging-related miRNAs in human mesenchymal stem cells (hMSCs) are limited. We observed that hMSC differentiation decreased with aging. We also identified that miR-10a expression was significantly decreased with age by comparing the miRNA expression of hMSCs derived from young and aged individuals. Therefore, we hypothesized that the downregulation of miR-10a may be associated with the decreased differentiation capability of hMSCs from aged individuals. Lentiviral constructs were used to up- or downregulate miR-10a in young and old hMSCs. Upregulation of miR-10a resulted in increased differentiation to adipogenic, osteogenic, and chondrogenic lineages and in reduced cell senescence. Conversely, downregulation of miR-10a resulted in decreased cell differentiation and increased cell senescence. A chimeric luciferase reporter system was generated, tagged with the full-length 3'-UTR region of KLF4 harboring the seed-matched sequence with or without four nucleotide mutations. These constructs were cotransfected with the miR-10a mimic into cells. The luciferase activity was significantly repressed by the miR-10a mimic, proving the direct binding of miR-10a to the 3'-UTR of KLF4. Direct suppression of KLF4 in aged hMSCs increased cell differentiation and decreased cell senescence. In conclusion, miR-10a restores the differentiation capability of aged hMSCs through repression of KLF4. Aging-related miRNAs may have broad applications in the restoration of cell dysfunction caused by aging. J. Cell. Physiol. © 2013 Wiley Periodicals, Inc.
    Digitale ISSN: 1097-4652
    Thema: Biologie , Medizin
    Publiziert von Wiley-Blackwell
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Publikationsdatum: 2011-06-01
    Beschreibung: Two coordination polymers, namely Zn(HL)(4,4′-bpy) 1.5 ( 1 ), [Zn 3 (L) 2 (BIMB) 2 ] · 5H 2 O ( 2 ) [H 3 L = 5-(4-carboxybenzyloxy)isophthalic acid, 4,4′-bpy = 4,4′-bipyridine, BIMB = 1,4-bis(1H-imidazol-1-yl)benzene] were synthesized under hydrothermal conditions. Their structures are determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectroscopy, and thermogravimetric (TG) analyses. Complex 1 features a 2D 4-connected network. Complex 2 is a 3D twofold interpenetrating (3,4,6)-connected net. In addition, the luminescent properties for 1 and 2 were studied in the solid state at room temperature.
    Print ISSN: 0044-2313
    Digitale ISSN: 1521-3749
    Thema: Chemie und Pharmazie
    Publiziert von Wiley-Blackwell
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...