bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Structure of Supercooled Water and the Mechanism of Homogeneous Nucleation of Ice Ih
Authors: Baumgärtel Helmut Gustav , Zimmermann Herbert W. 
Published: June 2013

Abstract
The mechanism of the phase transition of supercooled water to ice Ih at −36 ºC is discussed on a molecular level. The structure of liquid water is described by the interstitial model first proposed by Samoilov. It is consistent with the results of X-Ray and neutron scattering and the experimental results on the diverse properties of liquid water.
In order to illustrate our reflections several numerical calculations have been performed using exclusively experimental data.
From the temperatur dependence of the nucleation rate the minimum number of water molecules, which constitute the critical germ, and the volume of the critical germ are determined. The occupation numbers of the regular tridymite lattice and the vacancies of the interstitial lattice are evaluated.
The negative entropy of nucleation is discussed. It can be split in two contributions. They refer to the change of the statistics by the the transition from the protonucleus to the nucleus and the changes of the degrees of freedom of motion. Considering the simple model, the calculated value fits well to the experimental value of the nucleation entropy.
The transition state, which is a key point in the classical nucleation theory, is discussed on a molecular level. It has a lifetime of 0.57 × 10−12 s.
The nucleation volume is of the order nm3. One can expect that in this small volume density fluctuations exist in which especially the molecules in interstitial positions are involved. They are rich in energy and easily moveable. Statistical calculations deliver the deviation ±5 from the average value 23 of the number of molecules at interstitial positions in the nucleation volume. Corresponding density fluctuations have been observed by Huang et al. by very fast measurements of small angle X-ray scattering.
Neurodegenerative and inflammatory biomarkers in cerebrospinal fluid in patients with Cushing's syndrome in remission
Authors: Ragnarsson Oskar , Berglund Peter , Eder Derek N , Zetterberg Henrik , Hietala Max A , Blennow Kaj , Johannsson Gudmundur 
Published: June 2013

ObjectivePatients with Cushing's syndrome (CS) in long-term remission have impaired cognitive function. Cerebrospinal fluid (CSF) biomarkers are important diagnostic tools in the work-up of patients with cognitive impairment. The aim of this study was to analyze neurodegenerative and inflammatory biomarkers in the CSF of patients with CS in remission.DesignA cross-sectional, single-center study.PatientsTwelve women previously treated for CS and six healthy subjects.MeasurementsNeurodegenerative CSF markers: total tau, hyperphosphorylated tau, amyloid beta peptides, soluble amyloid precursor protein alpha and beta, neurofilament light proteins, glial fibrillary acidic protein, and monocyte chemoattractant protein 1; and inflammatory CSF markers: interferon gamma, interleukin (IL) 1B, IL2, IL4, IL5, IL8, IL10, IL12p70, IL13, and tumor necrosis factor alpha.ResultsThe mean age (mean±s.d.) was similar in patients with CS in remission (44.9±14 years) and healthy subjects (42.3±15.7 years;P=0.726). No differences were observed in the concentrations of any neurodegenerative biomarkers between the patients and healthy subjects. Nor were the concentrations of inflammatory biomarkers different between the groups.ConclusionsThe pattern of neurodegenerative and inflammatory biomarkers in the CSF of patients with CS in remission does not differ from that of the healthy subjects. The underlying mechanisms of the cognitive deficits in patients with CS in remission are different from those observed in patients with neurodegenerative disorders and remain to be explained.
The Length of the Shortest Telomere as the Major Determinant of the Onset of Replicative Senescence
Authors: Xu Zhou , Duc Khanh Dao , Holcman David , Teixeira Maria Teresa 
Published: June 2013

AbstractThe absence of telomerase in many eukaryotes leads to the gradual shortening of telomeres, causing replicative senescence. In humans, this proliferation barrier constitutes a tumor suppressor mechanism and may be involved in cellular aging. Yet the heterogeneity of the senescence phenotype has hindered the understanding of its onset. Here we investigated the regulation of telomere length and its control of senescence heterogeneity. Because the length of the shortest telomeres can potentially regulate cell fate, we focus on their dynamics in Saccharomyces cerevisiae. We developed a stochastic model of telomere dynamics built on the protein-counting model, where an increasing number of protein-bound telomeric repeats shift telomeres into a nonextendable state by telomerase. Using numerical simulations, we found that the length of the shortest telomere is well separated from the length of the others, suggesting a prominent role in triggering senescence. We evaluated this possibility using classical genetic analyses of tetrads, combined with a quantitative and sensitive assay for senescence. In contrast to mitosis of telomerase-negative cells, which produces two cells with identical senescence onset, meiosis is able to segregate a determinant of senescence onset among the telomerase-negative spores. The frequency of such segregation is in accordance with this determinant being the length of the shortest telomere. Taken together, our results substantiate the length of the shortest telomere as being the key genetic marker determining senescence onset in S. cerevisiae.
Novel protection solutions against environmental attack for light weight high temperature materials
Authors: Donchev Alexander , Schütze Michael 
Published: June 2013

ABSTRACTThe use of light weight structural materials such as titanium in transport systems like aero planes leads to a significant reduction in fuel consumption. However, titanium and its alloys cannot be used at elevated temperatures above 500°C for several reasons. Today aero engine compressors are made of a mixture of light Ti- and heavy Ni-alloys. The improvement of Ti-alloys to withstand the conditions in the high pressure compressor i.e. temperatures above 500°C would enable the manufacturing of a compressor from titanium as a whole with all its associated benefits. Intermetallic TiAl-alloys are another class of light weight materials for several high temperature applications. The use of TiAl as low pressure turbine (LPT) blades in the last sections of a large jet engine could save up to 150 kg of weight. In the last sections of the LPT the temperature is quite moderate (max. 650°C). The improvement of the high temperature capability of TiAl would allow its use in hotter sections of the engine with additional weight reduction. Similarly, the response performance of TiAl-turbocharger rotors in automotive engines would be much faster compared to the heavy Ni-based alloys used today. Furthermore higher rotation speeds are possible. Due to the novel so called fluorine effect the oxidation mechanism of TiAl can be altered. Fluorine-treated TiAl-components are protected by an alumina layer formed during high temperature exposure in oxidizing environments. This effect can be transferred to Ti-base materials if they are enriched with aluminum in a thin surface zone. The concepts and the results of high temperature exposure experiments of treated Ti- and TiAl-specimens are presented in this paper. They are discussed in the view of a use for real components.
Synthesis of Novel Halogen-Free Phenol Based Polymers and their utilization as Flame Retardant in Polypropylene system
Authors: Bakshi Ruchi , Ravichandran Sethumadhavan , Kiratitanavit Weeradech , Kumar Jayant , Nagarajan Ramaswamy 
Published: June 2013

ABSTRACTIncreasing awareness of toxicity of halogenated flame retardants (FRs) has resulted in stringent regulations that require the elimination of their use in plastics. Consequently, there is considerable interest for the development of new varieties of high performance FRs. Here, we report the synthesis of new class of polyphenol based FR additives. Preliminary investigations indicate that these FR materials can possibly work through a combination of radical scavenging and char-formation. The thermal stability and char yield of polyphenol samples were investigated by thermogravimetric analysis (TGA). Thermal characterization indicated that these polymers produce significant amount of carbonaceous char upon combustion.
Electrical, Optical and Ionic Probe inside Transmission Electron Microscope
Authors: Bai Xuedong , Xu Zhi , Gao Peng , Liu Kaihui , Wang Wenlong , Wang Enge 
Published: June 2013

ABSTRACTIn-situ transmission electron microscopy (TEM) method is powerful in a way that it can directly correlate the atomic-scale structure with physical and chemical properties. We will report on the construction and applications of the homemade in-situ TEM electrical and optical holders. Electrical transport of carbon nanotubes and photoconducting response on bending of individual ZnO nanowires have been studied inside TEM. Oxygen vacancy electromigration and its induced resistance switching effect have been probed in CeO2 films.
Characterization and thermomechanical properties of Ln2Zr2O7 (Ln=La, Pr, Nd, Eu, Gd, Dy) and Nd2Ce2O7
Authors: Kawano Toshiaki , Muta Hiroaki , Uno Masayoshi , Ohishi Yuji , Kurosaki Ken , Yamanaka Shinsuke 
Published: June 2013

ABSTRACTPyrochlore type compound Nd2(Zr,Ce)2O7 is considered to precipitate in ThO2-based fuel, that is not observed in irradiated UO2. In order to evaluate the influences on fuel properties, thermomechanical properties of the pyrochlore type compounds, Ln2Zr2O7 (Ln=La, Pr, Nd, Eu, Gd, Dy) and Nd2Ce2O7 were investigated. We synthesized the samples by solid-state reaction and pelletized by spark plasma sintering to make high density (≥ 90 %T.D.) pellets. The phase states and lattice parameters were examined by using X-ray diffraction and SEM/EDX analysis. The lattice parameters of Ln2Zr2O7 depended on the ionic radii of lanthanide ions. The heat capacity, thermal conductivity, linear thermal expansion coefficient, and elastic constants were also measured. It was confirmed that the thermal conductivities for Ln2Zr2O7 were lower than that for ThO2 and depended on Ln ionic radii. The values of elastic constants tended to increase with increasing the Ln ionic radii, corresponding to the thermal conductivity.
Salt as Alternative Energy Material to Fossil Fuel <potential use of sodium metal for hydrogen generation>
Authors: Murahara Masataka , Sato Yuji , Okawara Toshio 
Published: June 2013

ABSTRACTSalt is the raw material of sodium metal, which reacts with water to produce hydrogen for power generation. Sodium metal is solid matter and its specific gravity is low; therefore, it can be stored or transported for long at room temperature and under atmospheric pressure as oil and coal can. Sodium metal is produced with molten-salt electrolysis from sea salt, lake salt or rock salt, and securely kept immersed in kerosene for preventing it from reacting with air or moisture when transported to a consumer place; where it reacts violently with water to generate a large amount of hydrogen instantly. And sodium hydroxide, which is a reaction residue obtained after the production of hydrogen, is supplied as it is as the raw material of soda industries. Moreover, fresh water, sulfuric acid, hydrochloric acid, sodium hydroxide, and magnesium are generated as by-products in the processes of manufacturing sodium metal and generating hydrogen. Sodium metal can be an alternative energy material for hydrogen combustion power generation, having a far-reaching economic effect.
Sustainability in Materials Research in the EU: From FP7 to Horizon 2020
Authors: Tomellini Renzo , Benesch Johan Veiga 
Published: June 2013

ABSTRACTEnvironmental issues steadily receive more and more attention at EU policy level. This can for example be seen in the Raw Materials Initiative by DG Enterprise and Resource Efficient Europe by DG Environment which goes back to the theme of a sustainable economy as expressed by the Europe 2020 growth strategy. DG Research and Innovation supports related research activities. The Nanotechnology, Materials & Production (NMP) Theme in the FP7 Cooperation scheme has taken stock of this, by for example including aspects such as substitution, life cycle assessment, improved resource efficiency and better performance materials in the NMP calls for proposals. This is done with the aim to achieve a more green economy and fostering more sustainable consumption and production patterns.Research on better performing and sustainable materials will more than ever be a pre-condition to meeting such challenges. Progress will come through the development of intelligent materials that embed and transfer knowledge into products and processes or perform certain tasks, when in use or during manufacturing. Already, some 70 per cent of all technical innovations hinge directly or indirectly on the properties of the materials employed. We have passed from the perception "materials are in the drawer" to the perception "materials are the bottleneck". The next step can be "materials are the solution".At least 60 % of the total proposed Horizon 2020 budget is related to sustainable development, the vast majority of this expenditure contributing to mutually reinforcing climate and environmental objectives. In a resource-scarce Europe, new products must have low material / energy resource needs and high knowledge content. As stated in the Europe 2020 strategy, endorsed by EU leaders: “Europe must promote technologies and production methods that reduce natural resource use, and increase investment in the EU's existing natural assets”.Materials can have a large environmental impact in many of its stages, from sourcing, extraction, processing, auxiliary materials and processes, use and end of life fate. The choice or design of material solutions can thus have a great impact on the technologies in which they are used. Implying that a material could be an integral part of the solution to a problem created by the use of a specific technology. Such solutions could require entirely new materials either to replace a material or be part of a new technology based on better performing materials and eco-designed products.
Synthesis of a New Class of Molecule Li+@C60O–(OH)7 as a “Cation-Encapsulated Anion Nanoparticle” by Multihydroxylation of Li-Encapsulated Fullerene
Authors: Ueno Hiroshi , Nakamura Yuji , Ikuma Naohiko , Kokubo Ken , Oshima Takumi 
Published: June 2013

ABSTRACTTreatment of [Li+@C60](PF6–) with 30% fuming sulfuric acid and subsequent hydrolysis gave hydroxylated derivative Li+@C60O–(OH)7. Its structure was deduced by IR, NMR, MALDI-TOF/FAB MS, and elemental analysis. Notably, the reaction of [Li+@C60](PF6–) was site-selective, giving a single major isomer (ca. 70%) with two minor isomers, in marked contrast to the case of empty C60. Furthermore, the results clearly indicate that the internal Li cation was strongly shielded by the surface dipolar hydroxyl groups, and thus it appears that the properties of endohedral fullerenes can be controlled by the external modification of the fullerene cage. Whereas Li+@C60 is relatively insoluble, Li+@C60O–(OH)7 was found to be highly soluble in polar solvents such as DMSO and DMF. The increased solubility is especially desirable for biological/medicinal assays and applications in such research fields.
Quantitative Analysis of Raman Spectra in Si/SiGe Nanostructures
Authors: Mala Selina , Tsybeskov Leonid , Baribeau Jean-Marc , Wu Xiaohua , Lockwood David J. 
Published: June 2013

ABSTRACTWe present comprehensive quantitative analysis of Raman spectra in two-(Si/SiGe superlattices) and three-(Si/SiGe cluster multilayers) dimensional nanostructures. We find that the Raman spectra baseline is due to the sample surface imperfection and instrumental response associated with the stray light. The Raman signal intensity is analyzed, and Ge composition is calculated and compared with the experimental data. The local sample temperature and thermal conductivity are calculated, and the spectrum of longitudinal acoustic phonons is explained.
Micro-injection Molded Polymeric Surfaces for the Maintenance of Human Mesenchymal Stem Cells (hMSCs)
Authors: Casey Meghan E. , Rodgers John W. , LeBlon Courtney E. , Coulter John P. , Jedlicka Sabrina S. 
Published: June 2013

ABSTRACTIn this work, we take advantage of injection molding as a high volume and repeatable method to create surface areas for the growth of human mesenchymal stem cells (hMSCs). Ultraviolet lithography, combined with deep reactive ion etching, was used to generate micro-features over a relatively large surface area of a silicon wafer. The micro-featured silicon wafer was used as a mold insert for the micro-injection molding process to create polystyrene and low density polyethylene surfaces. Micro-geometry was used to alter the effective surface stiffness of the polymer substrate. Created samples were characterized via scanning electron microscopy and tensile testing. hMSCs were seeded onto samples for initial studies. Actin and vinculin were visualized through ICC to compare cytoskeletal elements. Changes in cell morphology were examined using ICC. Results indicate that injection molding of microfeatured substrates is a viable technique to produce surfaces amenable to stem cell growth.
Polarized Induced Magnetic Broadening of Photonic Activities in Fe3O4-Elastomer Composites
Authors: Ma Danhao , Hess Dustin T. , Shetty Pralav P , Adu Kofi W. , Bell Richard , Terrones Mauricio 
Published: June 2013

AbstractWe report a systematic study of polarization and magnetic field effects on the optical response of Fe3O4-silicone elastomer composite. The Fe3O4 particles were aligned in a silicone elastomer matrix with an external static magnetic field. Films of composites containing 5wt% of 20nm ≤ d ≤ 30nm Fe3O4 particles aligned in- and out-of-plane in the elastomer host were prepared. The optical spectra of the films were measured with the Perkin-Elmer Lambda 950 UV/vis/NIR spectrometer. We observed a systematic redshift in the optical response of the outof-plane composite films with increasing static magnetic field strength, which saturated near 600 Gauss. We obtained a maximum redshift of ∼46 nm at 600 Gauss. The observed redshift in the optical response of the out-of-plane composite film is attributed to the effect of the magnetic field. This facilitated the formation of the highly aligned particles that induced strong electric dipole in the aligned particles. Interestingly, there were no observable shifts with increasing magnetic field strength in the in-plane films, suggesting that the orientation (polarization) of the magnetic dipole and the induced electric dipole play a crucial role in the optical response.
Growth and Characteristics of a-Plane GaN/ZnO/GaN Heterostructure
Authors: Chang Chiao-Yun , Huang Huei-Min , Lan Yu-Pin , Lu Tien-Chang , Kuo Hao-Chung , Wang Shing-Chung , Tu Li-Wei , Hsieh Wen-Feng 
Published: June 2013

AbstractThe crystal structure of a-plane GaN/ZnO heterostructures on r-plane sapphire was investigated by using the XRD and TEM measurment. It was found the formation of (220) ZnGa2O4 and crystal orientation of semipolar (10$\bar 1$3) GaN at GaN/ZnO interface. The epitaxial relation of normal surface direction are the sapphire (1$\bar 1$02) // a-GaN (11$\bar 2$0) and ZnGa2O4 (220) // semi-polar GaN (10$\bar 1$$\bar 3$). Beside, the emission peak energy of ZnO appears shift about 60 meV in the GaN/ZnO/GaN heterostructures due to the re-crystallization of ZnO layer with Ga or N atom and the formation of the localized state.
Protons Crossing Triple Phase Boundaries based on Pd and Barium Zirconate: A Density Functional Theory Study
Authors: Malagoli Massimo , Bongiorno Angelo 
Published: June 2013

ABSTRACTDensity functional theory calculations are used to address the energetics of protons crossing “triple phase boundaries” based on Pd and barium zirconate. Our calculations show that the proton transfer reaction at these triple phase boundaries is controlled by the terminal layer of the electrolyte in contact with the metallic catalyst and gas phase. Hydrogen spilling onto the electrolyte surface is energetically favored at peripherical sites of the metal-electrolyte interface, and proton incorporation into the sub-surface region of the electrolyte involves energies of the order of 1 eV. At the triple phase boundary, the energy cost associated with the proton transfer reaction is controlled by both the nature of chemical contact and the Schottky barrier at the metal-electrolyte interface.
Fumarolic Activity, Acid-Sulfate Alteration, and High Sulfidation Epithermal Precious Metal Mineralization in the Crater of Kawah Ijen Volcano, Java, Indonesia
Authors: Scher Samantha , Williams-Jones A. E. , Williams-Jones Glyn 
Published: June 2013

Abstract
Opinion is divided over whether the fluid responsible for the formation of high sulfidation epithermal deposits is a vapor or a liquid, and whether it is entirely volcanic or of mixed volcanic-meteoric origin. Observations made at Kawah Ijen, an active stratovolcano (mainly andesitic in composition) located in the Ijen Caldera Complex in Java, Indonesia, are used to address these issues.
The Kawah Ijen crater is approximately 1 km in diameter, and hosts one of the world’s largest hyperacidic lakes (pH ~0). On the lake edge is a small and actively degassing solfatara field, which is surrounded by a much larger area of acid-sulfate alteration. This area was exposed during a phreatomagmatic eruption in 1817, which excavated the crater to a depth of 250 m, and comprises zones of residual silica, alunite-pyrite, and dickite/kaolinite. Based on the fractionation of 34S and 32S between alunite and pyrite, the acid-sulfate alteration occurred at a temperature between 200° and 300°C. High sulfidation epithermal mineralization accompanied the alteration in the form of massive and vein-hosted pyrite that contains up to 192 ppb Au, 9.2 ppm Ag, 6,800 ppm Cu, and 3,430 ppm As; these elements are invisible at the highest resolution of scanning electron microscopy, and thus either occur in the form of nanoparticles or are in solid solution in the pyrite. Condensed fumarolic gases released from the solfatara field and sampled at temperatures between 330° and 495°C contain up to 3 ppm Cu and 3.8 ppm As; the concentrations of Au and Ag are below detection. The pH of the condensed gas (water vapor) is ~−0.5.
The above observations support a model in which highly acidic gases condensed ~250 m beneath the floor of the crater. Depending on the fluid/rock ratio, the condensed liquids altered the andesitic host rocks by leaching them to leave behind a residue of “vuggy silica” (high fluid/rock ratio), by replacing the primary minerals with alunite and pyrite (intermediate fluid/rock ratio), or by converting them to dickite/kaolinite (lower fluid/rock ratio). Gold-, silver-, and copper-bearing phases were undersaturated in the condensed liquids. However, they were able to concentrate by adsorbing on the surfaces of the growing pyrite crystals, which developed p-type conductive properties as a result of the uptake of arsenic. The metals were incorporated in the pyrite either by their electrochemical reduction to form native metal nanoparticles or through coupled substitutions with arsenic for iron and sulfur. The results of this study provide compelling evidence that high sulfidation epithermal precious metal mineralization can form directly from condensed magmatic gases.