bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accurate Depth Determination for Moderate‐Magnitude Earthquakes Using Global Teleseismic Data
Authors: Craig T. J. 
Published: January 2019

AbstractThe determination of accurate source depths for globally observed earthquakes has long been one of the most problematic issues in earthquake source seismology. The optimal method for constraining the depths of teleseismically observed earthquakes is through the identification of near‐source surface reflections—depth phases. However, observing such phases is complicated by the relatively small amplitude of these arrivals compared to the background noise, particularly for earthquakes with Mw < 5.5. In this study, I present a methodology for leveraging the recent expansion in global seismic network coverage to enhance the identification of coherent depth phases through an automated stacking routine using a globally distributed array. While depth solutions for each individual depth phase are often nonunique, the identification of potential depths across multiple different phases, where each shows the correct distance‐dependent delay, provides a robust way to semiautomatically determine the source depth of an earthquake. I present a range of examples for the processing routine developed, along with an example for its regional application, to the North Chilean subduction zone. The technique presented offers an opportunity to improve depth estimates for earthquakes down to Mw4.9 and, requiring significantly less analyst input than other techniques offering a similar resolution, has the potential to be applied to large earthquake data sets.
Fe‐Binding Organic Ligands in the Humic‐Rich TransPolar Drift in the Surface Arctic Ocean Using Multiple Voltammetric Methods
Authors: Slagter Hans A. , Laglera Luis M. , Sukekava Camila , Gerringa Loes J. A. 
Published: January 2019

AbstractSamples inside and outside the Arctic Ocean's TransPolar Drift (TPD) have been analyzed for Fe‐binding organic ligands (Lt) with Competitive Ligand Exchange Adsorptive Stripping Voltammetry (CLE‐AdCSV) using salicylaldoxime (SA). This analysis is compared to prior analyses with CLE‐AdCSV using 2‐(2‐thiazolylazo)‐p‐cresol (TAC). The TPD's strong terrestrial influence is used to compare the performance of both CLE‐AdCSV methods in representing the nature of natural organic ligands. These measurements are compared against direct voltammetric determination of humic substances (HS) and spectral properties of dissolved organic matter. The relationship between the two CLE‐AdCSV derived [Lt] versus HS in the TPD has a comparable slope, with a 40% offset toward higher values obtained with SA. Higher [Lt] values inside the TPD, most probably due to HS, explain high dissolved Fe concentrations transported over the Arctic Ocean by the TPD. Outside of the TPD in the surface Arctic Ocean HS occur as well but at lower concentrations. Here changes in HS relate to changes in dissolved Fe concentration and to [Lt] obtained with SA, whereas [Lt] obtained with TAC remain constant. Moreover, with decreasing HS the offset between the methods using TAC and SA decreases. We surmise that in the presence of HS, the TAC method detects HS only either at higher concentrations or of specific composition. On the other hand, the SA method might overestimate [Lt], as an offset with the TAC method that remains constant where HS are not detected. Regardless, HS are the dominant type of Fe‐binding organic ligand in the surface of the Arctic Ocean.
Impact of Integrated Vertical Overlap of Cumulus and Stratus on the Global Precipitation and Radiation Processes in the Seoul National University Atmosphere Model Version 0 With a Unified Convection Scheme (SAM0‐UNICON)
Authors: Park Sungsu , Kim Siyun , Shin Jihoon , Oh Eunsil 
Published: January 2019

AbstractThe previously proposed parameterization for the integrated vertical overlap of cumulus and stratus is implemented online into the cloud microphysics and radiation schemes of the Seoul National University Atmosphere Model version 0 with a Unified Convection Scheme (SAM0‐UNICON). Instead of a single‐merged cloud, the modified radiation scheme handles cumulus, stratus, and stratiform snow, separately, with each type having its own optical properties and vertical overlap structures. The integrated cloud overlap parameterization implemented into the cloud microphysics schemes do not reduce the biases of surface precipitation rate (PRECT) and cloud radiative forcing. Although it changes the overlap structures of clouds and precipitation areas, as well as the associated cloud microphysical processes either directly or indirectly, strong cancelation occurs among these terms, resulting in small changes to the global‐mean PRECT and cloud radiative forcing. The integrated cloud overlap parameterization implemented into the radiation scheme has a substantial impact on the simulated climate: the global‐mean cloud radiative forcing decreases substantially, mainly due to the separate treatment of radiative properties of individual cumulus, stratus, and stratiform snow, and PRECT exhibits strong regional responses. Sensitivity simulations showed that vertical cloud overlap exerts a weaker influence on the global‐mean PRECT than the previous off‐line simulations, implying that the indirect effect offsets the direct effect. In contrast to the off‐line simulations, the enhanced randomness of cumulus overlap increases PRECT over the western Pacific warm pool region. Our study indicates that vertical cloud overlap has substantial impacts on global climate through complex interactions with other physical processes.
Modeling Depth of the Redox Interface at High Resolution at National Scale Using Random Forest and Residual Gaussian Simulation
Authors: Koch Julian , Stisen Simon , Refsgaard Jens C. , Ernstsen Vibeke , Jakobsen Peter R. , Højberg Anker L. 
Published: January 2019

AbstractThe management of water resources needs robust methods to efficiently reduce nitrate loads. Knowledge on where natural denitrification takes place in the subsurface is thereby essential. Nitrate is naturally reduced in anoxic environments and high‐resolution information of the redox interface, that is, the depth of the uppermost reduced zone is crucial to understand the variability of the denitrification potential. In this study we explore the opportunity to use random forest (RF) regression to model redox depth across Denmark at 100‐m resolution based on ~13,000 boreholes as training data. We highlight the importance of expert knowledge to guide the RF model in areas where our conceptual understanding is not represented correctly in the training data set by addition of artificial observations. We apply random forest regression kriging in which sequential Gaussian simulation models the RF residuals. The RF model reaches a R2 score of 0.48 for an independent validation test. Including sequential Gaussian simulation honors observations through local conditioning, and the spread of 800 realizations can be utilized to map uncertainty. Emphasis is put on adequate handling of nonstationarities in variance and spatial correlation of the RF residuals. The RF residuals show no spatial correlation for large parts of the modeling domain, and a local variance scaling method is applied to account for the nonstationary variance. Moreover, we present and exemplify a framework where newly acquired field data can easily be integrated into random forest regression kriging to quickly update local models.
New strategy for designing orangish-red-emitting phosphor via oxygen-vacancy-induced electronic localization
Authors: Wei Yi , Xing Gongcheng , Liu Kang , Li Guogang , Dang Peipei , Liang Sisi , Liu Min , Cheng Ziyong , Jin Dayong , Lin Jun 
Published: January 2019

AbstractPhosphor-converted white-light-emitting diodes (pc-WLED) have been extensively employed as solid-state lighting sources, which have a very important role in people’s daily lives. However, due to the scarcity of the red component, it is difficult to realize warm white light efficiently. Hence, red-emitting phosphors are urgently required for improving the illumination quality. In this work, we develop a novel orangish-red La4GeO8:Bi3+ phosphor, the emission peak of which is located at 600 nm under near-ultraviolet (n-UV) light excitation. The full width at half maximum (fwhm) is 103 nm, the internal quantum efficiency (IQE) exceeds 88%, and the external quantum efficiency (EQE) is 69%. According to Rietveld refinement analysis and density functional theory (DFT) calculations, Bi3+ ions randomly occupy all La sites in orthorhombic La4GeO8. Importantly, the oxygen-vacancy-induced electronic localization around the Bi3+ ions is the main reason for the highly efficient orangish-red luminescence. These results provide a new perspective and insight from the local electron structure for designing inorganic phosphor materials that realize the unique luminescence performance of Bi3+ ions.
Transmission–reflection optoacoustic ultrasound (TROPUS) computed tomography of small animals
Authors: Merčep Elena , Herraiz Joaquín L. , Deán-Ben Xosé Luís , Razansky Daniel 
Published: January 2019

AbstractRapid progress in the development of multispectral optoacoustic tomography techniques has enabled unprecedented insights into biological dynamics and molecular processes in vivo and noninvasively at penetration and spatiotemporal scales not covered by modern optical microscopy methods. Ultrasound imaging provides highly complementary information on elastic and functional tissue properties and further aids in enhancing optoacoustic image quality. We devised the first hybrid transmission–reflection optoacoustic ultrasound (TROPUS) small animal imaging platform that combines optoacoustic tomography with both reflection- and transmission-mode ultrasound computed tomography. The system features full-view cross-sectional tomographic imaging geometry for concomitant noninvasive mapping of the absorbed optical energy, acoustic reflectivity, speed of sound, and acoustic attenuation in whole live mice with submillimeter resolution and unrivaled image quality. Graphics-processing unit (GPU)-based algorithms employing spatial compounding and bent-ray-tracing iterative reconstruction were further developed to attain real-time rendering of ultrasound tomography images in the full-ring acquisition geometry. In vivo mouse imaging experiments revealed fine details on the organ parenchyma, vascularization, tissue reflectivity, density, and stiffness. We further used the speed of sound maps retrieved by the transmission ultrasound tomography to improve optoacoustic reconstructions via two-compartment modeling. The newly developed synergistic multimodal combination offers unmatched capabilities for imaging multiple tissue properties and biomarkers with high resolution, penetration, and contrast.
Electron-Phonon Coupling as the Source of 1/f Noise in Carbon Soot
Authors: Mihaila M. , Ursutiu D. , Sandu I. 
Published: January 2019

AbstractTwo 1/f noise peaks were found in a carbon soot resistor at voltages characteristic of Kohn anomalies in graphite. The ratio of the electron-phonon coupling matrix elements at the anomalies calculated from the noise peak intensities is the same as the one obtained from the Raman frequencies. This demonstrates that the electron-phonon coupling is the microscopic source of 1/f noise in carbon soot. A new, very general formula was deduced for the frequency exponent, wherein nonlinearity and dispersion are the only ingredients. The interplay between nonlinearity and dispersion in this formula describes the sublinear-supralinear transitions experimentally observed at both anomalies in the voltage dependence of the frequency exponent. A quadratic dependence of the 1/f noise parameter on the matrix element is proposed and applied to explain the M-shape of the 1/f noise in graphene. We found that the frequency exponent mimics the dependence of the noise intensity in the whole voltage range, while both are the image of the graphite phonon spectrum. This implies that the source of nonlinearity is in the electron-phonon coupling which modulates the slope of the spectrum. It requires the presence of 1/f noise in the thermal noise background of the resistor till phonon frequencies.
Geometrical Dependence on the Onset of Surface Plasmon Polaritons in THz Grid Metasurfaces
Authors: Papari Gian Paolo , Koral Can , Andreone Antonello 
Published: January 2019

AbstractThe transmission response of metallo-dielectric grid metasurfaces is experimentally investigated through Terahertz Time Domain Spectroscopy and the corresponding effective dielectric function is retrieved. Using a lumped element model we can determine the dependence of the effective plasma frequency (the transition frequency) on the metasurface filling factor F. The change of the transition frequency vs. F spans over one order of magnitude and sets the threshold between the metamaterial (homogeneous) and the photonic crystal (diffraction-like) regime, ruling the onset of two different Surface Plasmon Polaritons, spoof and high order. Field symmetry and spatial extension of such excitations are investigated for the possible applications of THz grid metasurfaces in bio- and chemical sensing and sub-wavelength imaging.
Age-related differences in the bone marrow stem cell niche generate specialized microenvironments for the distinct regulation of normal hematopoietic and leukemia stem cells
Authors: Lee Ga-Young , Jeong Seon-Yeong , Lee Hae-Ri , Oh Il-Hoan 
Published: January 2019

AbstractThe bone marrow (BM) microenvironment serves as a stem cell niche regulating the in vivo cell fate of normal hematopoietic stem cells (HSC) as well as leukemia stem cells (LSCs). Accumulating studies have indicated that the regeneration of normal HSCs and the process of leukemogenesis change with advancing age. However, the role of microenvironmental factors in these age-related effects are unclear. Here, we compared the stem cell niche in neonatal and adult BM to investigate potential differences in their microenvironmental regulation of both normal and leukemic stem cells. We found that the mesenchymal niche in neonatal BM, compared to adult BM, was characterized by a higher frequency of primitive subsets of mesenchymal stroma expressing both platelet-derived growth factor receptor and Sca-1, and higher expression levels of the niche cross-talk molecules, Jagged-1 and CXCL-12. Accordingly, normal HSCs transplanted into neonatal mice exhibited higher levels of regeneration in BM, with no difference in homing efficiency or splenic engraftment compared to adult BM. In contrast, in vivo self-renewal of LSCs was higher in adult BM than in neonatal BM, with increased frequencies of leukemia-initiating cells as well as higher lympho-myeloid differentiation potential towards biphenotypic leukemic cells. These differences in LSC self-renewal capacity between neonates and adults was abrogated by switching of recipients, confirming their microenvironmental origin. Our study provides insight into the differences in leukemic diseases observed in childhood and adults, and is important for interpretation of many transplantation studies involving neonatal animal models.
Sex Differences in Mouse Popliteal Lymph Nodes
Authors: Dill-Garlow Riva , Chen KuanHui Ethan , Walker Ameae M. 
Published: January 2019

AbstractFemales have more robust immune responses than males, well-illustrated by the degree of inflammation elicited during delayed-type hypersensitivity (DTH) responses. Here, we have investigated underlying sex differences that may contribute to differential footpad DTH responses using wildtype and four core genotypes (FCG) mice and popliteal lymphnode cellularity and gene expression. DTH responses in XX and XY FCG females showed no role for almost all genes expressed on sex chromosomes. After then filtering-out genes differentially expressed between XX and XY females, only one gene was sexually differentially expressed in wildtype mice, glycosylation-dependent cell adhesion molecule 1 (Glycam1), expressed 7-fold higher in females. Glycam1 facilitates leukocyte entry through high endothelial venules. Consistent with greater Glycam1 expression, female nodes contained twice as many cells. While females had more memory T cells in their nodes, males had a higher percentage of T regulatory cells. This sexual dimorphism in wildtype animals manifested pre-pubertally, was enhanced post-pubertally, and was eliminated by castration. The formation of male gonads is determined by the expression of Sry. Sry overexpression, which does not affect testosterone levels, produced an exaggerated male phenotype. We conclude that Sry expression through formation of the male gonad indirectly negatively impacts the potential for local inflammation.
Molecular Complexity Calculated by Fractal Dimension
Authors: von Korff Modest , Sander Thomas 
Published: January 2019

AbstractMolecular complexity is an important characteristic of organic molecules for drug discovery. How to calculate molecular complexity has been discussed in the scientific literature for decades. It was known from early on that the numbers of substructures that can be cut out of a molecular graph are of importance for this task. However, it was never realized that the cut-out substructures show self-similarity to the parent structures. A successive removal of one bond and one atom returns a series of fragments with decreasing size. Such a series shows self-similarity similar to fractal objects. Here we used the number of distinct fragments to calculate the fractal dimension of the molecule. The fractal dimension of a molecule is a new matter constant that incorporates all features that are currently known to be important for describing molecular complexity. Furthermore, this is the first work that reveals the fractal nature of organic molecules.
Synthesis of nanogate structure in GO-ZnS sandwich material
Authors: Kumar Praveen , Luwang Meitram Niraj 
Published: January 2019

AbstractGraphite Oxide (multi-layer) composite with other materials has a huge application in various field of science, due to its excellent and unique properties. Even though from past decade, immense research has been done by materials scientists in this field, but the chemistry is still not yet satisfactory. Here, in this work, through the discovery of Nanogate structure, we have reported for the first time the experimental results that enlightened the clear chemistry between the GO and ZnS which is further supported by the DFT calculations. This novel synthesis method led to the discovery of nanogate structure sandwiched between the GO layers. The nanogate formation also shows enhanced properties for various applications like photocatalytic activities, etc. Due to the nanogate formation, there might be a possibility of enormous generation of electrons on excitation of the composite materials, which can be a boom for various applications like photocatalysis, water splitting, solar cell, etc.
Progesterone Treatment Attenuates Glycolytic Metabolism and Induces Senescence in Glioblastoma
Authors: Atif Fahim , Yousuf Seema , Espinosa-Garcia Claudia , Sergeeva Elena , Stein Donald G. 
Published: January 2019

AbstractWe examined the effect of progesterone treatments on glycolytic metabolism and senescence as possible mechanisms in controlling the growth of glioblastoma multiforme (GBM). In an orthotopic mouse model, after tumor establishment, athymic nude mice received treatment with progesterone or vehicle for 40 days. Compared to controls, high-dose progesterone administration produced a significant reduction in tumor size (~47%) and an increased survival rate (~43%) without any demonstrable toxicity to peripheral organs (liver, kidney). This was accompanied by a significant improvement in spontaneous locomotor activity and reduced anxiety-like behavior. In a follow-up in vitro study of U87MG-luc, U87dEGFR and U118MG tumor cells, we observed that high-dose progesterone inhibited expression of Glut1, which facilitated glucose transport into the cytoplasm; glyceraldehyde 3-phosphate dehydrogenase (GAPDH; a glycolysis enzyme); ATP levels; and cytoplasmic FoxO1 and Phospho-FoxO1, both of which control glycolytic metabolism through upstream PI3K/Akt/mTOR signaling in GBM. In addition, progesterone administration attenuated EGFR/PI3K/Akt/mTOR signaling, which is highly activated in grade IV GBM. High-dose progesterone also induced senescence in GBM as evidenced by changes in cell morphology and β-galactocidase accumulation. In conclusion, progesterone inhibits the modulators of glycolytic metabolism and induces premature senescence in GBM cells and this can help to reduce/slow tumor progression.
RNA-Seq transcriptome analysis shows anti-tumor actions of melatonin in a breast cancer xenograft model
Authors: Jardim-Perassi Bruna Victorasso , Alexandre Pâmela A. , Sonehara Nathalia M. , de Paula-Junior Rubens , Reis Júnior Osvaldo , Fukumasu Heidge , Chammas Roger , Coutinho Luiz Lehmann , Zuccari Debora Aparecida Pires de Campos 
Published: January 2019

AbstractMelatonin is a pleiotropic anti-cancer molecule that controls cancer growth by multiple mechanisms. RNA-Seq can potentially evaluate therapeutic response and its use in xenograft tumor models can differentiate the changes that occur specifically in tumor cells or in the tumor microenvironment (TME). Melatonin actions were evaluated in a xenograft model of triple-negative breast cancer. Balb/c nude mice bearing MDA-MB-231 tumors were treated with melatonin or vehicle. RNA-Seq was performed on the Illumina HiSeq. 2500 and data were mapped against human and mouse genomes separately to differentiate species-specific expression. Differentially expressed (DE) genes were identified and Weighted Gene Co-expression Network Analysis (WGCNA) was used to detect clusters of highly co-expressed genes. Melatonin treatment reduced tumor growth (p < 0.01). 57 DE genes were identified in murine cells, which represented the TME, and were mainly involved in immune response. The WGCNA detected co-expressed genes in tumor cells and TME, which were related to the immune system among other biological processes. The upregulation of two genes (Tnfaip8l2 and Il1f6) by melatonin was validated in the TME, these genes play important roles in the immune system. Taken together, the transcriptomic data suggests that melatonin anti-tumor actions occur through modulation of TME in this xenograft tumor model.
Solid stress-induced migration is mediated by GDF15 through Akt pathway activation in pancreatic cancer cells
Authors: Kalli Maria , Minia Angeliki , Pliaka Vaia , Fotis Christos , Alexopoulos Leonidas G. , Stylianopoulos Triantafyllos 
Published: January 2019

AbstractSolid stress is a biomechanical abnormality of the tumor microenvironment that plays a crucial role in tumor progression. When it is applied to cancer cells, solid stress hinders their proliferation rate and promotes cancer cell invasion and metastatic potential. However, the underlying mechanisms of how it is implicated in cancer metastasis is not yet fully understood. Here, we used two pancreatic cancer cell lines and an established in vitro system to study the effect of solid stress-induced signal transduction on pancreatic cancer cell migration as well as the mechanism involved. Our results show that the migratory ability of cells increases as a direct response to solid stress. We also found that Growth Differentiation Factor 15 (GDF15) expression and secretion is strongly upregulated in pancreatic cancer cells in response to mechanical compression. Performing a phosphoprotein screening, we identified that solid stress activates the Akt/CREB1 pathway to transcriptionally regulate GDF15 expression, which eventually promotes pancreatic cancer cell migration. Our results suggest a novel solid stress signal transduction mechanism bringing GDF15 to the centre of pancreatic tumor biology and rendering it a potential target for future anti-metastatic therapeutic innovations.