bluuebunny/crossref_metadata_2025_split huggingface dataset:
An in situ fracture device to image lipids in single cells using ToF‐SIMS
Authors: Lanekoff Ingela , Kurczy Michael E. , Adams Kelly L. , Malm Jakob , Karlsson Roger , Sjövall Peter , Ewing Andrew G. 
Published: June 2010

AbstractTime‐of‐Flight Secondary Ion Mass Spectrometry (ToF‐SIMS) imaging yields molecule‐specific images showing the spatial distribution of specific lipids with submicron resolution, making it a potentially powerful method for studying a variety of biological questions in single cells. In order to make possible the analysis of hydrated cells in vacuum, we have designed a device for in situ freeze‐fracture of cell samples. PC12 cells are frozen between two silicon shards in a sandwich geometry, and the fracture is conducted under vacuum inside the analysis chamber of the instrument. After freeze‐fracture, ToF‐SIMS analysis was carried out using a Bi cluster ion source, providing high‐resolution images of single cells. We also show that when combining freeze‐fracture and cluster SIMS imaging, low abundant biologically important lipids, specifically PE, PC and non‐SM PC, can be imaged in single cells. Finally, K+ ion localization was used as a diagnostic to identify fracture planes through the cell for these fractured samples. Copyright © 2010 John Wiley & Sons, Ltd.
Application of TOF‐SIMS to the direct determination of syringyl to guaiacyl (S/G) ratio of lignin
Authors: Saito Kaori , Kishimoto Takao , Matsushita Yasuyuki , Imai Takanori , Fukushima Kazuhiko 
Published: June 2010

AbstractThe lignin syringyl to guaiacyl (S/G) ratio, the composition of monomeric units, is an important parameter that is widely used to obtain information on the complex polymer structure of lignin present in plant cell walls. We assessed the reliability of time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) for determining the S/G ratio using monomer, dimer and polymer model compounds of lignin. In the case of the monomer and dimer, the S/G ratios were much higher than the actual molar S/G ratios. In contrast, for the aryl ether 8‐O‐4′‐linked polymers, the S/G ratios estimated were similar to the actual S/G molar ratios, suggesting that the ionization efficiencies of the characteristic ions of S and G units detected from the synthetic lignin polymer compounds were similar. The results suggest that TOF‐SIMS is useful for rapid and convenient determination of the lignin S/G ratio in plants. Copyright © 2010 John Wiley & Sons, Ltd.
Statistics of electron and ion emission from single massive cluster impacts
Authors: Verkhoturov S. V. , Eller M. J. , Della‐Negra S. , Rickman R. D. , Locklear J. E. , Schweikert E. A. 
Published: June 2010

AbstractWe demonstrate several fundamental characteristics of coemissions of secondary ions and electrons from homogeneous targets. The custom‐built device consists of an electron microscope equipped with a fast digital camera, and a time‐of‐flight secondary ion mass spectrometer. The device operates in event‐by‐event emission/detection mode with synchronized detection of electrons and ions emitted from single projectile impact. The data are in the form of images of detected electrons which correspond to coordinates of impacts. Further, for the coordinates of each impact, there is also the ion information from that impact. The bombardment of different homogenous targets (Gramicidin S, Glycine, Guanine, Al, Au) by 15 keV C60+ and 30 keV C602+ shows abundant coemission of negative ions and electrons. We compute from the data the distribution of number of electrons detected per projectile impact. Our observations indicate that electrons are emitted independently from the type or number of the coemitted negative ions. The abundant coemission of negative ions and electrons from homogenous targets implies strong electron excitation in the energized nanovolume. Independence of emission of negative ions and electrons indicates that the mechanism of ionization is due to electron exchange between the emitted species in the excited nanovolume rather than via electron attachment. Copyright © 2010 John Wiley & Sons, Ltd.
Geochemical biosignatures preserved in microbially altered basaltic glass
Authors: Banerjee N. R. , Izawa M. R. M. , Sapers H. M. , Whitehouse M. J. 
Published: June 2010

AbstractMicrobes play an important role in the alteration of volcanic rocks emplaced on the seafloor as pillow basalts and hyaloclastites. Microbially altered basaltic glass hosts characteristic hollow etch structures, which are commonly filled and preserved by the precipitation of new mineral phases within the etch structures. Bioalteration textures occur in two distinct morphologies: micron‐scale granular aggregates, and long tubules (up to hundreds of microns). SIMS analyses of basaltic glass samples with abundant tubular bioalteration from the Ontong Java Plateau reveal significant chemical variations in areas with tubular microbial etch structures including: alkalis, which show depletion in Na and enrichment in K; enrichments in the alkaline elements (Ca, Sr, Ba) and the high field strength elements (Ti, Y, Zr); the first row transition metals V, Cr and Mn are slightly enriched, while Fe, Co, Ni, Cu and Zn are depleted; W and the lanthanides are enriched in tubule‐bearing regions; slight enrichments in U and P are also observed. SEM imaging following SIMS analysis revealed complex micron‐scale spongy textures that may be related to microbial glass dissolution. Copyright © 2010 John Wiley & Sons, Ltd.
Analysis of organic semiconductor multilayers with Ar cluster secondary ion mass spectrometry
Authors: Ninomiya Satoshi , Ichiki Kazuya , Yamada Hideaki , Nakata Yoshihiko , Seki Toshio , Aoki Takaaki , Matsuo Jiro 
Published: June 2010

AbstractThe demand for direct analytical techniques for characterization and damage evaluation of organic devices has increased dramatically in recent years, along with an increase in the importance of these devices. In this study, we demonstrate direct analysis of model structures for organic light emitting diode (OLED) devices by using SIMS with large Ar cluster ion beams. We prepared single and multilayer films of organic semiconductor materials by vacuum evaporation and analyzed their surfaces with time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). Under bombardment with large Ar cluster ions, the predominant species observed were molecular ions from the organic materials, while small fragment ions were strongly suppressed. Moreover, the multilayer films were depth profiled with Ar cluster ion beams, and the interfaces between the organic layers could be clearly distinguished. These results show the promising potential of large Ar cluster ion beams for direct analysis of real organic semiconductor devices. Copyright © 2010 John Wiley & Sons, Ltd.
Photon emission from massive projectile impacts on solids
Authors: Fernandez‐Lima F. A. , Pinnick V. T. , Della‐Negra S. , Schweikert E. A. 
Published: June 2010

AbstractFirst evidence of photon emission from individual impacts of massive gold projectiles on solids for a number of projectile‐target combinations is reported. Photon emission from individual impacts of massive Aun+q (1⩽n⩽400; q = 1–4) projectiles with impact energies in the range of 28–136 keV occurs in less than 10 ns after the projectile impact. Experimental observations show an increase in the photon yield from individual impacts with the projectile size and velocity. Concurrently with the photon emission, electron emission from the impact area has been observed below the kinetic emission threshold and under unlikely conditions for potential electron emission. We interpret the puzzling electron emission and correlated luminescence observation as evidence of the electronic excitation resulting from the high‐energy density deposited by massive cluster projectiles during the impact. Copyright © 2010 John Wiley & Sons, Ltd.
Determining major and trace element compositions of exposed melt inclusions in minerals using ToF‐SIMS
Authors: Marques A. F. A. , Scott S. D. , Sodhi R. N. S. 
Published: June 2010

AbstractMelt inclusions (MI), tiny portions of liquid silicate (melt) and gases trapped inside crystals during their growth in magmatic environments, are a valuable geological tool for understanding the evolution of magmas and the source of metals for some ore deposits. Owing to their small size, acquiring the chemical composition of MI is a meticulous process.Time‐of‐Flight Secondary Ion Mass Spectrometry (ToF‐SIMS) is a powerful surface analytical technique that provides excellent sensitivity with high mass and spatial resolution. We have begun the study of MI in rocks associated with modern and ancient seafloor hydrothermal systems. The main objective of our experiments is to obtain quantitative data for which we have used as standards quenched glasses with known similar compositions. Specimens were polished and different cleaning conditions (presputtering with either Ar or Cs ions) were examined in order to optimize our results, which were obtained using a Bi cluster ion source. Good quantitative results were obtained for selected major and trace elements (e.g. Mg, Na, K, V, La and Ce). Copyright © 2010 John Wiley & Sons, Ltd.
Strain imaging of magnetic domain structures in the magnetic head of a hard disk drive
Authors: Takata Keiji 
Published: June 2010

AbstractDetection and imaging of magnetic‐field‐induced strains using scanning probe microscopy enable us to observe magnetic domain structures. Domain structures in a magnetization reversal process of the lateral‐recording head in a hard disk drive were investigated by scanning over the air‐bearing surface of the head. External magnetic fields were applied by the writing coil. In the process, magnetic domains in the bottom pole were divided into right and left regions in the cross‐track direction, having opposite magnetizations. The domain boundary moved to right or left according to writing currents, and vanished by larger currents than 15 mA. Hemispherical domain structures with a diameter of around 0.6 µm, consisting of two opposite magnetizations in the direction of the applied magnetic field, were observed in several portions of the bottom pole. The domain structures also vanished with increasing field strength. Copyright © 2010 John Wiley & Sons, Ltd.
Nanostructure formation onto a tip of field gas ion emitter by field‐assisted oxygen etching
Authors: Kobayashi Y. , Yasuhiko S. , Morikawa Y. , Kajiwara K. , Hata K. 
Published: June 2010

AbstractFor focused ion beam technology in the next generation, an adequate emitter shape for field gas ion source was investigated to obtain a higher angular current density, dI/dΩ. A < 111 > ‐oriented tungsten emitter with a trimer‐terminated nanostructure was fabricated by field‐assisted oxygen etching method. Since this method does not utilize thermodynamic phenomena, e.g. faceting of crystal plane with a thermal treatment or pseudomorphic growth of surface layer, shape of the emitter tip has a rotational symmetry with no ridge lines which brings about a decrease of axial beam current. In the preliminary experiment for helium gas, an extraction of ion current was attempted from the trimer at the apex tip, and the increases in helium ion current and dI/dΩ in proportion to the gas pressure were observed. Copyright © 2010 John Wiley & Sons, Ltd.
X‐ray photoreduction of U(VI)‐bearing compounds
Authors: Mercier‐Bion F. , Drot R. , Ehrhardt J. J. , Lambert J. , Roques J. , Simoni E. 
Published: June 2010

AbstractDuring XPS analysis, the soft X‐ray‐induced reduction of metals such as Cr(VI) and Ce(IV) in oxides has been reported in the literature and some mechanisms have been proposed to explain this phenomenon. The reduction of U(VI) by the beam during X‐ray Photoelectron Spectroscopy has been already reported in the literature but only for U(VI) sorbed or precipitated onto solids with reducing properties (as micas or pyrites) for whose Fe(II) can also induce the reduction of U(VI), or onto TiO2 whose the photocatalytic properties are well known. The objective of this paper is to investigate the effects of X‐ray beam on U(VI) bulk compounds (UO3, UO2(OH)2, (UO2)2SiO4, UO2(CH3COO)2 and UO2C2O4). Successive U4f, U5f, C1s XPS spectra were recorded and compared as a function of the irradiation time. The XPS photoreduction of U(VI) into U(IV) is only observed for uranyl compounds containing organic matter (uranyl acetate and uranyl oxalate). Considering the evolution of the C1s signal during the X‐ray irradiation, a significant decrease of the C O component simultaneously to the U(VI) reduction is observed, which suggests a desorption of CO or other volatile organic products from the solid surface. All these results on U(VI) bulk compounds indicate the important role of organic carbon species in the photoreduction process and to explain these observations, a photoreduction mechanism has been suggested. Copyright © 2010 John Wiley & Sons, Ltd.
Mechanical property and corrosion resistance of zirconia/polydopamine nanocomposite multilayer films fabricated via a novel non‐electrostatic layer‐by‐layer assembly technique
Authors: Ou Junfei , Wang Jinqing , Qiu Yinong , Liu Lanzhong , Yang Shengrong 
Published: June 2010

AbstractZirconia/polydopamine (ZrO2/PDA) nanocomposite multilayer films were constructed on Si substrate via a novel nonelectrostatic layer‐by‐layer (NELBL) assembly technique. The building block of this technique is the newly reported dopamine molecule, which can be attached to almost all material surfaces and undergo oxidation‐polymerization to form PDA layers; more importantly, the outer hydroxyl groups of the PDA layer can chelated with certain inorganic oxide nanoparticles to generate oxide films. Thus, ZrO2/PDA nanocomposite multilayer films were fabricated by sequential NELBL deposition of PDA and ZrO2 nanoparticles. The formation of the ZrO2/PDA nanocomposite multilayer films was monitored by the water contact angle (WCA) and ellipsometric thickness measurements, while the microstructure of the fabricated films was analyzed by means of atomic force microscope (AFM), field emission scanning electron microscope (FESEM), X‐ray photoelectron spectrum (XPS), and X‐ray diffraction (XRD) analysis. The mechanical and anticorrosion behaviors of the annealed ZrO2/PDA nanocomposite multilayers were found to be greatly enhanced as compared with that of the annealed homogeneous ZrO2 film. The better mechanical and anticorrosion behaviors of the annealed ZrO2/PDA nanocomposite multilayers than the annealed homogeneous ZrO2 film may be closely related to their special microstructure. Namely, the organic–inorganic hybrid microstructure of the annealed ZrO2/PDA nanocomposite multilayers may largely account for the increased nanohardness and corrosion resistance. Copyright © 2010 John Wiley & Sons, Ltd.
Characterization of potato starch fractions and their interaction with hydrocolloids
Authors: Sikora Marek , Tomasik Piotr , Krystyjan Magdalena 
Published: June 2010

AbstractCommercial potato starch was separated through sedimentation into three fractions of the size < 25, 25–70 and >70 µm estimated with the laser particle meter method and <21.6, 21.7–30.6 and >30.7 µm according to the Sartorius balance method. Amylose and amylopectin content in particular fractions did not depend on the granule size. Number average and weight average molecular weight slightly decreased and phosphorus content increased with the size of granules in the fractions. Starch fractions and, for comparison, non‐fractionated starch were gelatinized in aqueous solutions of arabic, carob, karaya and xanthan gums and carrageenan. Except for the arabic gum, all tested hydrocolloids decreased onset temperature of gelation, T0, of all starch fractions. Carob and xanthan gums and carrageenan the most remarkably decreased that parameter for large fraction, whereas other gums most considerably decreased T0 of starch of the medium fraction. Effect of gums upon such parameters of the characteristics of gelation as ηmax, ηmin and η25°C depended irregularly on the size of starch granules. In gels from gums and small granules, the role of G′ and G″ module differed from that in gels from the other starch fractions.
Starch thermal transitions comparatively studied by DSC and MTDSC
Authors: Xie Fengwei , Liu Wei‐Chen , Liu Peng , Wang Jun , Halley Peter J. , Yu Long 
Published: June 2010

AbstractThe gelatinisation process of waxy starch was studied using both differential scanning calorimetry (DSC) and modulated temperature DSC (MTDSC). It was revealed that the results from the two techniques, especially the onset gelatinisation temperature, were slightly different, which may be due to the MTDSC principle and the mechanism of starch gelatinisation. Thus, it is suggested to avoid using MTDSC alone in the characterisation of starch thermal transitions especially in a quantitative way. However, MTDSC has the advantage in understanding the gelatinisation mechanism since it can separate the capacity change (reversible thermal event) from kinetic components (irreversible event). The stepwise change on reversible heat flow measured by MTDSC during gelatinisation was considered due to the phase transition of highly constrained starch polymer chains in granular packing. On the other hand, the glass transition of gelatinised starch (also thermoplastic starch) could not necessarily be detected by conventional DSC or MTDSC. However, by using a high‐speed DSC method, the extremely weak glass transition of the gelatinised starch with low moisture content could be enlarged and detected, which confirms the existence of glass transition of the gelatinised starch with low moisture content. This knowledge is helpful in the processing of starch‐based foods and polymeric materials.
Sin3a Is Required by Sertoli Cells to Establish a Niche for Undifferentiated Spermatogonia, Germ Cell Tumors, and Spermatid Elongation
Authors: Payne Christopher J. , Gallagher Shannon J. , Foreman Oded , Dannenberg Jan Hermen , Depinho Ronald A. , Braun Robert E. 
Published: June 2010

Abstract
Microenvironments support the maintenance of stem cells and the growth of tumors through largely unknown mechanisms. While cell-autonomous chromatin modifications have emerged as important determinants for self-renewal and differentiation of stem cells, a role for non-cell autonomous epigenetic contributions is not well established. Here, we genetically ablated the chromatin modifier Swi-independent 3a (Sin3a) in fetal Sertoli cells, which partly comprise the niche for male germline stem cells, and investigated its impact on spermatogenic cell fate and teratoma formation in vivo. Sertoli cell-specific Sin3a deletion resulted in the formation of few undifferentiated spermatogonia after birth while initially maintaining spermatogenic differentiation. Stem cell-associated markers Plzf, Gfra1, and Oct4 were downregulated in the mutant fetal gonad, while Sertoli cell markers Steel and Gdnf, which support germ cells, were not diminished. Following birth, markers of differentiating spermatogonia, Kit and Sohlh2, exhibited normal levels, but chemokine-signaling molecules chemokine (C-X-C motif) ligand 12 (CXCL12)/stromal cell-derived factor 1 (SDF1) and chemokine (C-X-C motif) receptor 4 (CXCR4), expressed in Sertoli cells and germ cells, respectively, were not detected. In the juvenile, mutant testes exhibited a progressive loss of differentiating spermatogonia and a block in spermatid elongation, followed by extensive germ cell degeneration. Sertoli cell-specific Sin3a deletion also suppressed teratoma formation by fetal germ cells in an in vivo transplantation assay. We conclude that the epigenome of Sertoli cells influences the establishment of a niche for germline stem cells as well as for tumor initiating cells.
ATP-Sensitive K+ Channel-Deficient Dilated Cardiomyopathy Proteome Remodeled by Embryonic Stem Cell Therapy
Authors: Zlatkovic-Lindor Jelena , Arrell D. Kent , Yamada Satsuki , Nelson Timothy J. , Terzic Andre 
Published: June 2010

Abstract
Transplantation of pluripotent stem cells has proven beneficial in heart failure, yet the proteomic landscape underlying repair remains largely uncharacterized. In a genetic model of dilated cardiomyopathy elicited by pressure overload in the KCNJ11 (potassium inwardly rectifying channel, subfamily J, member 11) null mutant, proteome-wide profiles were here resolved by means of a systems approach prior to and following disease manifestation in the absence or presence of embryonic stem cell treatment. Comparative two-dimensional gel electrophoresis revealed a unique cardiomyopathic proteome in the absence of therapy, remodeled in response to stem cell treatment. Specifically, linear ion trap quadrupole-Orbitrap mass spectrometry determined the identities of 93 and 109 differentially expressed proteins from treated and untreated cardiomyopathic hearts, respectively. Mapped protein–protein relationships and corresponding neighborhoods incorporated the stem cell-dependent subproteome into a nonstochastic network with divergent composition from the stem cell-independent counterpart. Stem cell intervention produced a distinct proteome signature across a spectrum of biological processes ranging from energetic metabolism, oxidoreductases, and stress-related chaperones to processes supporting protein synthesis/degradation, signaling, and transport regulation, cell structure and scaffolding. In the absence of treatment, bioinformatic interrogation of the disease-only proteome network prioritized adverse cardiac outcomes, ablated or ameliorated following stem cell transplantation. Functional and structural measurements validated improved myocardial contractile performance, reduced ventricular size and decreased cardiac damage in the treated cohort. Unbiased systems assessment unmasked “cardiovascular development” as a prioritized biological function in stem cell-reconstructed cardiomyopathic hearts. Thus, embryonic stem cell treatment transformed the cardiomyopathic proteome to demote disease-associated adverse effects and sustain a procardiogenic developmental response, supplying a regenerative substrate for heart failure repair.
Aberrant Epigenetic Silencing of Tumor Suppressor Genes Is Reversed by Direct Reprogramming
Authors: Ron-Bigger Shulamit , Bar-Nur Ori , Isaac Sara , Bocker Michael , Lyko Frank , Eden Amir 
Published: June 2010

Abstract
Direct reprogramming procedures reset the epigenetic memory of cells and convert differentiated somatic cells into pluripotent stem cells. In addition to epigenetic memory of cell identity, which is established during development, somatic cells can accumulate abnormal epigenetic changes that can contribute to pathological conditions. Aberrant promoter hypermethylation and epigenetic silencing of tumor suppressor genes (TSGs) are now recognized as an important mechanism in tumor initiation and progression. Here, we have studied the fate of the silenced TSGs p16(CDKN2A) during direct reprogramming. We find that following reprogramming, p16 expression is restored and is stably maintained even when cells are induced to differentiate. Large-scale methylation profiling of donor cells identified aberrant methylation at hundreds of additional sites. Methylation at many, but not all these sites was reversed following reprogramming. Our results suggest that reprogramming approaches may be applied to repair the epigenetic lesions associated with cancer.
Fabrication of EuF3‐Mesocrystals in a Gel Matrix
Authors: Lausser Christine , Kumke Michael U. , Antonietti Markus , Cölfen Helmut 
Published: June 2010

AbstractEuropium(III) fluoride mesocrystals were synthesised in an organic matrix. This matrix is a gel formed by Eu3+ ions and a polycarboxylate/sulfonate copolymer, ACUSOL 588G. In the gel phase, the local amount of europium ions is very high since Eu3+ acts as a crosslinker, and crystallisation occurs upon addition of F–. Nucleated seed crystals in the gel phase grow by further ion attachment and form mesocrystals by mutual orientation of the EuF3 particles in the gel. We propose a dipole field as reason for this alignment and that the dipolar character of the particles originates from adsorption of the polyelectrolyte on charged crystal faces.