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  • 1
    Publikationsdatum: 2016-08-23
    Beschreibung: The Mesozoic plate tectonic history of Gondwana-derived crustal blocks of the Tibetan Plateau is hotly debated, but so far, paleomagnetic constraints quantifying their paleolatitude drift history remain sparse. Here, we compile existing data published mainly in Chinese literature and provide a new, high-quality, well-dated paleomagnetic pole from the ca. 180 Ma Sangri Group volcanic rocks of the Lhasa terrane that yields a paleolatitude of 3.7°S ± 3.4°. This new pole confirms a trend in the data that suggests that Lhasa drifted away from Gondwana in Late Triassic time, instead of Permian time as widely perceived. A total northward drift of ~4500 km between ca. 220 and ca. 130 Ma yields an average south-north plate motion rate of 5 cm/yr. Our results are consistent with either an Indian or an Australian provenance of Lhasa.
    Print ISSN: 0091-7613
    Digitale ISSN: 1943-2682
    Thema: Geologie und Paläontologie
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2011-12-06
    Beschreibung: We study the polarization properties of the light field under a dynamic ocean surface using realistic linear and nonlinear ocean surface waves. The three-dimensional polarized radiative transfer of the dynamic ocean–atmosphere system is considered using a Monte Carlo vector radiative transfer simulation for arbitrary depth. The program is validated with measurement data taken in Hawaii during the Radiance in a Dynamic Ocean project. The main focus of this study is the influence of the wind-driven ocean waves on the polarization patterns and statistics at different optical depths under various conditions of light wavelength and solar incidence. Of special interest is the effect of the nonlinearity of the surface waves on the polarization statistics. To facilitate the study, phase-resolved direct simulations of the linear and nonlinear surface wavefields are performed using a high-order spectral method. The results show that the time-averaged degree of polarization within the Snell's window is dependent on the mean square slope of the ocean surface. Higher mean square slope, or wind speed, leads to a smaller degree of polarization. At the same time, the variability of the degree of polarization has a strong dependence on the surface roughness. A rougher ocean surface induces higher variability of the degree of polarization. The effect of wave nonlinearity can be neglected for the mean value of polarization, but is manifested in the variability of the degree of polarization, with a general increase in the variance with increasing wave nonlinearity. The present findings provide possible mechanisms for characterizing the dynamic ocean surface based on underwater polarized light measurements.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    facet.materialart.
    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2019
    Beschreibung: 〈p〉The transport of nanoparticles at bio-nano interfaces is essential for many cellular responses and biomedical applications. How two-dimensional nanomaterials, such as graphene and transition-metal dichalcogenides, diffuse along the cell membrane is, however, unknown, posing an urgent and important issue to promote their applications in the biomedical area. Here, we show that the transport of graphene oxides (GOs) sandwiched inside cell membranes varies from Brownian to Lévy and even directional dynamics. Specifically, experiments evidence sandwiched graphene–cell membrane superstructures in different cells. Combined simulations and analysis identify a sandwiched GO–induced pore in cell membrane leaflets, spanning unstable, metastable, and stable states. An analytical model that rationalizes the regimes of these membrane-pore states fits simulations quantitatively, resulting in a mechanistic interpretation of the emergence of Lévy and directional dynamics. We finally demonstrate the applicability of sandwiched GOs in enhanced efficiency of membrane-specific drug delivery. Our findings inform approaches to programming intramembrane transport of two-dimensional nanomaterials toward advantageous biomedical applications.〈/p〉
    Digitale ISSN: 2375-2548
    Thema: Allgemeine Naturwissenschaft
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2011-04-20
    Beschreibung: China and other rapidly developing economies face the dual challenge of substantially increasing yields of cereal grains while at the same time reducing the very substantial environmental impacts of intensive agriculture. We used a model-driven integrated soil–crop system management approach to develop a maize production system that achieved mean maize yields of 13.0 t ha−1 on 66 on-farm experimental plots—nearly twice the yield of current farmers’ practices—with no increase in N fertilizer use. Such integrated soil–crop system management systems represent a priority for agricultural research and implementation, especially in rapidly growing economies.
    Schlagwort(e): Sustainability Science
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2012-03-22
    Beschreibung: Turbulence in the upper ocean generates fluctuations in temperature and salinity, which result in variations in inherent optical properties (IOPs) and further change the underwater light field. A simulation-based study is performed for the radiative transfer (RT) of natural light in the turbulent flows in the upper ocean. For a canonical problem of turbulent shear flow interacting with the sea surface with and without surface waves, large-eddy simulations are performed for fluid motions and the transport of temperature and salinity. Based on the resolved turbulence temperature and salinity fields, IOP variations are quantified, and the inhomogeneous RT equation is then simulated using a Monte Carlo method. Through the simulations of a variety of cases with different flow, temperature, and salinity conditions, the statistics of downwelling irradiance are quantified and analyzed. It is found that the vertical profile of the mean downwelling irradiance is mainly determined by the vertical structure of the mean values of the IOPs; and turbulence effect is manifested in the horizontal variations of the downwelling irradiance. The magnitude of the irradiance variation is governed by the differences in the temperature and salinity between their values at the surface and in the deep region. In the presence of surface waves, the irradiance variation is enhanced due to the surface deformation, which is also largely affected by wave–turbulence interaction. The LES and inhomogeneous RT simulation may provide a useful tool for the characterization of upper-ocean turbulence processes based on underwater RT measurements.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    facet.materialart.
    Unbekannt
    American Physical Society (APS)
    Publikationsdatum: 2014-08-28
    Beschreibung: Author(s): Yulin Pan and Dick K. P. Yue We consider the inertial range spectrum of capillary wave turbulence. Under the assumptions of weak turbulence, the theoretical surface elevation spectrum scales with wave number k as Iη∼kα, where α=α0=-19/4, energy (density) flux P as P1/2. The proportional factor C, known as the Kolmogorov constan... [Phys. Rev. Lett. 113, 094501] Published Wed Aug 27, 2014
    Schlagwort(e): Nonlinear Dynamics, Fluid Dynamics, Classical Optics, etc.
    Print ISSN: 0031-9007
    Digitale ISSN: 1079-7114
    Thema: Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2014-03-19
    Beschreibung: Two altimetry models extracting DEM (Digital Elevation Model) with the GBSAR (Ground-Based Synthetic Aperture Radar) technology are studied and their accuracies are analyzed in detail. The approximate and improved altimetry models of GBSAR were derived from the spaceborne radar altimetry based on the principles of the GBSAR technology. The error caused by the parallel ray approximation in the approximate model was analyzed quantitatively, and the results show that the errors cannot be ignored for the ground-based radar system. For the improved altimetry model, the elevation error expression can be acquired by simulating and analyzing the error propagation coefficients of baseline length, wavelength, differential phase and range distance in the mathematical model. By analyzing the elevation error with the baseline and range distance, the results show that the improved altimetry model is suitable for high-precision DEM and the accuracy can be improved by adjusting baseline and sho...
    Print ISSN: 1755-1307
    Digitale ISSN: 1755-1315
    Thema: Geographie , Geologie und Paläontologie , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Publikationsdatum: 2014-08-22
    Beschreibung: Mutations in LRRK2 are one of the primary genetic causes of Parkinson's disease (PD). LRRK2 contains a kinase and a GTPase domain, and familial PD mutations affect both enzymatic activities. However, the signaling mechanisms regulating LRRK2 and the pathogenic effects of familial mutations remain unknown. Identifying the signaling proteins that regulate LRRK2 function and toxicity remains a critical goal for the development of effective therapeutic strategies. In this study, we apply systems biology tools to human PD brain and blood transcriptomes to reverse-engineer a LRRK2- centered gene regulatory network. This network identifies several putative master regulators of LRRK2 function. In particular, the signaling gene RGS2 , which encodes for a GTPase-activating protein (GAP), is a key regulatory hub connecting the familial PD-associated genes DJ-1 and PINK1 with LRRK2 in the network. RGS2 expression levels are reduced in the striata of LRRK2 and sporadic PD patients. We identify RGS2 as a novel interacting partner of LRRK2 in vivo. RGS2 regulates both the GTPase and kinase activities of LRRK2. We show in mammalian neurons that RGS2 regulates LRRK2 function in the control of neuronal process length. RGS2 is also protective against neuronal toxicity of the most prevalent mutation in LRRK2 , G2019S. We find that RGS2 regulates LRRK2 function and neuronal toxicity through its effects on kinase activity and independently of GTPase activity, which reveals a novel mode of action for GAP proteins. This work identifies RGS2 as a promising target for interfering with neurodegeneration due to LRRK2 mutations in PD patients.
    Print ISSN: 0964-6906
    Digitale ISSN: 1460-2083
    Thema: Biologie , Medizin
    Publiziert von Oxford University Press
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2010-05-28
    Beschreibung: Lung cancer is the leading cause of cancer-related mortality worldwide, with non-small-cell lung carcinomas in smokers being the predominant form of the disease. Although previous studies have identified important common somatic mutations in lung cancers, they have primarily focused on a limited set of genes and have thus provided a constrained view of the mutational spectrum. Recent cancer sequencing efforts have used next-generation sequencing technologies to provide a genome-wide view of mutations in leukaemia, breast cancer and cancer cell lines. Here we present the complete sequences of a primary lung tumour (60x coverage) and adjacent normal tissue (46x). Comparing the two genomes, we identify a wide variety of somatic variations, including 〉50,000 high-confidence single nucleotide variants. We validated 530 somatic single nucleotide variants in this tumour, including one in the KRAS proto-oncogene and 391 others in coding regions, as well as 43 large-scale structural variations. These constitute a large set of new somatic mutations and yield an estimated 17.7 per megabase genome-wide somatic mutation rate. Notably, we observe a distinct pattern of selection against mutations within expressed genes compared to non-expressed genes and in promoter regions up to 5 kilobases upstream of all protein-coding genes. Furthermore, we observe a higher rate of amino acid-changing mutations in kinase genes. We present a comprehensive view of somatic alterations in a single lung tumour, and provide the first evidence, to our knowledge, of distinct selective pressures present within the tumour environment.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lee, William -- Jiang, Zhaoshi -- Liu, Jinfeng -- Haverty, Peter M -- Guan, Yinghui -- Stinson, Jeremy -- Yue, Peng -- Zhang, Yan -- Pant, Krishna P -- Bhatt, Deepali -- Ha, Connie -- Johnson, Stephanie -- Kennemer, Michael I -- Mohan, Sankar -- Nazarenko, Igor -- Watanabe, Colin -- Sparks, Andrew B -- Shames, David S -- Gentleman, Robert -- de Sauvage, Frederic J -- Stern, Howard -- Pandita, Ajay -- Ballinger, Dennis G -- Drmanac, Radoje -- Modrusan, Zora -- Seshagiri, Somasekar -- Zhang, Zemin -- England -- Nature. 2010 May 27;465(7297):473-7. doi: 10.1038/nature09004.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Bioinformatics and Computational Biology, Genentech Inc., South San Francisco, California 94080, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20505728" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Carcinoma, Non-Small-Cell Lung/*genetics ; DNA Mutational Analysis ; Genome, Human/*genetics ; Humans ; Lung Neoplasms/*genetics ; Male ; Middle Aged ; Models, Biological ; Point Mutation/*genetics ; Selection, Genetic/genetics
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2011-02-12
    Beschreibung: Endocrine tumors such as aldosterone-producing adrenal adenomas (APAs), a cause of severe hypertension, feature constitutive hormone production and unrestrained cell proliferation; the mechanisms linking these events are unknown. We identify two recurrent somatic mutations in and near the selectivity filter of the potassium (K(+)) channel KCNJ5 that are present in 8 of 22 human APAs studied. Both produce increased sodium (Na(+)) conductance and cell depolarization, which in adrenal glomerulosa cells produces calcium (Ca(2+)) entry, the signal for aldosterone production and cell proliferation. Similarly, we identify an inherited KCNJ5 mutation that produces increased Na(+) conductance in a Mendelian form of severe aldosteronism and massive bilateral adrenal hyperplasia. These findings explain pathogenesis in a subset of patients with severe hypertension and implicate loss of K(+) channel selectivity in constitutive cell proliferation and hormone production.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3371087/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3371087/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Choi, Murim -- Scholl, Ute I -- Yue, Peng -- Bjorklund, Peyman -- Zhao, Bixiao -- Nelson-Williams, Carol -- Ji, Weizhen -- Cho, Yoonsang -- Patel, Aniruddh -- Men, Clara J -- Lolis, Elias -- Wisgerhof, Max V -- Geller, David S -- Mane, Shrikant -- Hellman, Per -- Westin, Gunnar -- Akerstrom, Goran -- Wang, Wenhui -- Carling, Tobias -- Lifton, Richard P -- DK54983/DK/NIDDK NIH HHS/ -- K01 AR060300/AR/NIAMS NIH HHS/ -- T32 GM007205/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2011 Feb 11;331(6018):768-72. doi: 10.1126/science.1198785.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Genetics, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21311022" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adrenal Cortex Neoplasms/*genetics/metabolism/pathology ; Adrenal Glands/pathology ; Adrenocortical Adenoma/*genetics/metabolism/pathology ; Aldosterone/*metabolism ; Cell Line ; Cell Proliferation ; Female ; G Protein-Coupled Inwardly-Rectifying Potassium ; Channels/chemistry/*genetics/metabolism ; Humans ; Hyperaldosteronism/*genetics/metabolism/pathology ; Hyperplasia ; Hypertension/*genetics/metabolism ; Male ; Mutant Proteins/chemistry/genetics/metabolism ; *Mutation ; Potassium/metabolism ; Protein Multimerization ; Sodium/metabolism ; Zona Glomerulosa/metabolism/pathology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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