bluuebunny/crossref_metadata_2025_split huggingface dataset:
UV Laser Induced Amino Group Substitution on Pet Ligament to Promote Inhibition of Collagen
Authors: Omuro H. , Hamada K. , Nakajima T. , Sinpuku E. , Nakagawa M. , Fukuda H. , Murahara M. 
Published: April 2011

ABSTRACTAn amino functional group was substituted on a PET film surface for the purpose of making the implantation of collagen readily. The PET has been widely used for medical materials such as an artificial ligament because of its strength and antibacterial action. However, when transplanted in human bodies, its compatibility is not good enough to adapt to the collagen which grows from living body tissues. To avoid this reaction medicine has been used clinically which makes the PET fiber into a mesh state and after the transplantation into a human body, makes the tissue intrude in the PET fiber. However, this method has not shown satisfactory enough results to promote rehabilitation. If the living body compatibility of materials is improved the initial adapting power with the tissue can be enhanced.Then we substituted NH2, which has a high affinity for collagen, on the PET surface by ArF laser. PET is highly hydrophobic and does not dissolve well in aqueous solutions. To avoid this reaction we make a thin ammonium fluoride solution layer on the PET surface with capillary phenomenon. Then an ArF laser beam was irradiated vertically onto the sample. The result of this treatment shows that an untreated sample having the contact angle of 80° with water and the bonding strength of only 1.0 kg/cm2 with collagen was improved to have the contact angle of 22° and the bonding strength to be 12 kg/cm2.When the treated sample had been implanted into the subcutaneous tissue of a rabbit's regiones dorsales, existence of leukocyte colonies that are indicators of human histocompatibility was confirmed on the hydrophilic parts of the sample.
Engineering Micrometer and Nanometer Scale Features in Polydimethylsiloxane Elastomers for Controlled Cell Function
Authors: Feinberg Adam W. , Seegert Charles A. , Gibson Amy L. , Brennan Anthony B. 
Published: April 2011

ABSTRACTCell movement, differentiation and metabolic function must be controlled in precise ways to produce both regenerated tissues such as bone and functional tissue equivalents such as immuno-isolated islet cells. Close examination of extracellular matrix (ECM) reveals structures on the micron and nanometer scale that are shown to influence these factors and therefore we hypothesize that cells will move based on topographical cues in the scaffold. We have engineered siloxane elastomer surfaces that mimic the ECM by combining micron and nanometer scale topographic features. Micron scale pillars and ridges ranging in height from 1.5 to 5 microns and separated by 5, 10 and 20 microns were fabricated in a silicon wafer using micro- processing techniques and replicated in polydimethylsiloxane (PDMS) elastomer. Nanometer scale pillars, ridges and more complex shapes ranging in height from 12 to 300 nanometers were superimposed on the micron scale features using nanolithography. This was achieved by using a tapping mode tip in the atomic force microscope (AFM) to plastically deform the substrate surface. The AFM enabled nano-features to be placed on sloped surfaces and added directly to the PDMS elastomer surface. Surface topography was examined using scanning electron microscopy, atomic force microscopy and white light interference profilometry to verify surface modifications and fidelity of the replication process. Results indicate that it is possible to create spatially engineered surface textures from 10-5 m to 10-8 m in size, in specified patterns, by using a combination of microprocessing and nanolithography techniques. As better understanding of ECM function and design is gained, the processing methods outlined here will assist in fabricating tissue engineering scaffolds optimized at the nanometer and micron scale.
Bioerodible Polypyrrole
Authors: Zelikin Alexander , Shastri Venkatram , Lynn David , Farhadi Jian , Martin Ivan , Langer Robert 
Published: April 2011

ABSTRACTConductive polymers such as polypyrrole (Ppy) are potentially useful as an active interface for altering cellular processes and function. Their utilization in medically related applications however have been substantially held back by their non-degradable nature. Herein we report a novel approach to creation of bioerodible polypyrroles via modification of pyrrole beta-carbon with an ionizable moiety. It has been shown that the erosion rate of acid-bearing derivative of polypyrrole increases with pH, which is consistent with the pH dependent ionization of carboxylic acid group. The novel paradigm proposed for the creation of bioerodible polypyrroles allows for simple and efficient control over the erosion rate of the substrate independent of the polymer chain length, via the choice of the terminal ionizable group and its concentration along the polymer backbone.
Imaging of Subsurface Defects in Bivalve Shells by Photothermal Techniques
Authors: Gómez-Martínez O. , Zambrano-Arjona M. , Alvarado-Gil J.J. 
Published: April 2011

ABSTRACTThe potential of photothermal radiometry for subsurface defect imaging in shells of Crassostrea virginica is explored. It is shown that using this technique in the modality of modulated frequency, it is possible to obtain photothermal images in the case of small thermal diffusion lengths. By controlling the modulation frequency, it is shown that the technique can be useful in the study of buried defects in the shell. The application of this technique in monitoring living organisms is discussed.
Treatment and Analysis of a Paint Chip from “Water Lilies” a Fire Damaged Monet
Authors: Miller Sharon K.R. , Banks Bruce A. , Tollis Greg 
Published: April 2011

ABSTRACTA museum fire in 1958 severely damaged a Monet “Water Lilies” (1916-1926) painting that was on display. The surface of the painting is very dark with areas of blistering and charring. Over the years, traditional techniques have been found to be ineffective at removal of the soot and char from the surface. The painting, which is now in the care of the New York University (NYU) Conservation Center of the Institute of Fine Arts, was the subject of a study to determine if atomic oxygen treatment could remove the soot and char without damaging the fragile painting underneath. For test purposes, a small chip of paint was removed from the edge of the painting by a conservator at NYU and supplied to NASA Glenn Research Center for atomic oxygen treatment and analysis. The diffuse spectral reflectance, at three locations on the paint chip, was monitored at intervals during the atomic oxygen treatment process. Photo documentation of the chip during treatment was also performed. The color contrast was calculated from the spectral reflectance data as a function of treatment duration. Results of the testing indicated that the contrast improved as a result of the treatment, and the differentiation of colors on the surface was significantly improved. Soot and char could be removed without visibly affecting the gross surface features such as impasto areas. These results indicate the feasibility for the treatment of the “Water Lilies” painting.
The Condition and Cleaning of Acrylic Emulsion Paintings
Authors: Murray Alison , Berenfeld Celina Contreras de , Chang S.Y. Sue , Jablonski Elizabeth , Klein Tracey , Riggs Marion C. , Robertson Elizabeth C. , Tse W.M. Anthony 
Published: April 2011

ABSTRACTCleaning acrylic emulsion paintings is challenging because of the material properties of the paint films, including their solubility. The goal of this work was to learn more about the effect of aqueous treatments on acrylic paints. Paint manufacturers were asked for their recommendations for cleaning these paintings and conservators were asked to comment on the damage observed in them and on the treatments applied. Responses showed that aqueous cleaning treatments are used, despite the associated risks, and that more technical information is needed about the effects of cleaning. The experimental section of this paper evaluated the changes in physical and mechanical properties of aged cobalt blue paint as a result of exposure to aqueous cleaning solutions. The results indicated that short immersions in these solutions caused a drop in most mechanical properties, but longer immersions did not; the drop after the short immersions was mostly due to the great increase in dimensional thickness of the paint films. Longer conservation treatment times are not being advocated.
Practical Bloomery Smelting
Authors: Sauder W. H. Lee , Williams Henry G. 
Published: April 2011

ABSTRACTThe art and technique of bloomery smelting, man's original method for winning metalliciron from its ore, has been largely lost in recent centuries. Many reconstructions of this technique have been attempted by archaeologists in the last 30 years. These experimental smelts have tended to be rather disappointing in terms of the production of usable iron; nonetheless, many conclusions have been drawn from this work.The main goal of our work with bloomery smelting is the production of iron for the creation of forged sculpture. Our focus on producing a usable product has led us to a somewhat different view of the technology from what has been published in the archaeological literature.In this paper, we will briefly summarize our work through the spring of 2000, which has been published elsewhere. We'll then report our recent findings from the 2000-2001 smelting season, describing a typical smelt of the most efficient smelting regimen we have yet discovered. We will pay particular attention to methods that differ from those of other experimenters, especially in regards to blowing rate, slag management, and the recycling of furnace products. Finally, we'll point toward areas of upcoming research.
Achieving High Spatial Resolution in Elemental Mapping of Metal Samples from Archaeological Contexts
Authors: Lea Scott , Baer Don , Paparazzo Ernesto , Northover Peter , Salter Chris 
Published: April 2011

ABSTRACTImproving the characterisation of archaeological artifacts brings a need to understand better the relationships between composition, structure and properties. With archaeological material there is also a requirement to consider the effects of ageing and environmental interactions in altering the original structure and composition, both in the bulk and at the surface. However, curatorial constraints and, frequently, the condition of the objects preclude the sampling methods required for the most powerful means of structural analysis of materials, the high resolution transmission electron microscope. The samples normally available are small bulk samples and we must find other means of maximising spatial resolution in microchemical and microstructural analysis of both bulk and surface regions of the samples. This paper describes ways in which this is being achieved using the scanning proton microprobe (SPM) with both particle induced X-ray emission (PIXE) and Rutherford back scattered proton (RBS) spectra at resolutions down to ca. 1:m, electron probe microanalysis (EPMA) at 250-300nm, and scanning Auger microscopy (SAM) at resolutions of 10-20nm, but only from the surface layers of atoms in a sample. Examples will be given which demonstrate the contribution that each instrument can make, and that new and useful information is obtained each time resolution is increased. They will also show that structural features can be identified which are invisible to other microscopies. It will also be shown how modern PC-based software has greatly enhanced the mapping capability of all instruments.
A Materials Investigation into the Metal Composition and Coating Structures of Four Ming Dynasty Cast Iron Statues, with Subsequent Discussion and Development of a Treatment Protocol
Authors: Moffatt Elizabeth A. , Shugar Aaron N. , Sirois P. Jane , Stock Susan 
Published: April 2011

ABSTRACTFour iron statues dated by inscription to the Ming Dynasty, China, (1491 A.D.) were investigated for their metal composition and coating structures. The investigation was initiated with the intent of ascertaining whether any prior treatment had been done and to determine the present condition of the objects. During visual examination and simple surface cleaning, it became apparent that the objects had some form of surface decoration and polychrome. On closer examination, gilding, lacquer, and traces of pigment around the hat, eyes, and garments were visible. A sample of the metal was taken for metallography and chemical compositional analysis. Samples were taken from the surface of the four objects to identify the composition of the observed decoration and corrosion. The results revealed that the statues are white cast iron and were fully decorated with multiple colours and gilding as well as being sequentially lacquered. Recommendations for the cleaning and conservation of these and similar objects are given.
A 16,000 Year-Old Ceramic Human-Figurine from Maina, Russia
Authors: Vandiver Pamela B. , Vasil'ev Sergey A. 
Published: April 2011

ABSTRACTThe ceramic technology used to construct and fire an image of a human figurine excavated from a 16,000 year old layer at the archaeological site of Maina on the Yenesei River in southern Siberia is reconstructed using x-radiography, x-ray diffraction, optical and scanning electron microscopy with simultaneous energy dispersive x-ray analysis, and electron beam microprobe analysis. Evidence is provided from the archaeological excavation as well as radiocarbon dating. Comparative studies of the clayey soils at the site add contextual and environmental evidence to establish this remarkable technology as having been carried out at the site using a local clay-loam resource.
Pixe, Electron Microprobe Data, and Experimental Archaeology: Tell el-Ajjul and Pilot Studies of Gold Granulation Joining Practices in the Mediterranean Bronze Age
Authors: Politis Thea 
Published: April 2011

ABSTRACTThis paper discusses the results of a pilot study using Proton Induced X-ray Emission (PIXE) analysis of gold granulated objects from the Bronze Age site of Tell el-Ajjul in Southern Palestine obtained with the Oxford University proton microprobe. Using modern granulated samples with known smithing processes as points of comparison, it is demonstrated how information on ancient joining practices may be accurately gauged. The importance of characterizing objects of known provenance is emphasized in a discussion of archaeological context. It is argued that the building of a large Mediterranean-wide database of granulation analyses can add new depths to our understanding of temporal, social, cultural and technological relationships in the past.
Microstructural Analysis of A Steel Tool Rescued from Historical Site in Rio De Janeiro State
Authors: Campos Guadalupe do Nascimento , Solórzano Guillermo 
Published: April 2011

ABSTRACTThe present work has as its objective a metallographic analysis of a metallic archaeological artifact using methods of optical microscopy (OM) and scanning electron microscopy (SEM). The object of study is a scythe from the Brazilian colonial period, dated beginning of XVII century, removed from an archaeological site, Sítio Cruzeiro, in excavations conducted by researchers of the Brazilian Archaeological Institute. Sample preparation required a meticulous procedure in view of the fragility of the object. The scythe has been suffering the action of oxidation-corrosion for over 300 years, allowing the impregnation of mineral sediments. A detailed metallographic analysis coupled with spectroscopic SEM measurements concluded that of the object was made of steel with a carbon content of the order of 0.4%. The equi-axed microstructure together with the alignment of inclusions strongly suggest a metal working procedure followed by heat treatment and a slow cooling rate as the method used for fabricating the artifact.
Investigation of N2 Plasma Effects on the Density Profile of Hydrogen Silsesquioxane Thin Films
Authors: Lee H. J. , Lin E. K. , Wu W. L. , Fanconi B. M. , Lan J. K. , Cheng Y. L. , Liou H. C. , Wang Y. L. , Feng M. S. , Chao C. G. 
Published: April 2011

ABSTRACTThe density depth profile and chemical bond structure of hydrogen silsesquioxane (HSQ) thin films treated with an N2 plasma with varying power and exposure time were measured using specular x-ray reflectivity (SXR) and Fourier transform infrared (FTIR) spectroscopy. The SXR data indicate that the density profile of an untreated HSQ film is not uniform and four layers with different electron densities were required to fit the SXR data. For HSQ films treated with either increasing plasma power or plasma exposure time, the film roughness increased and a densified layer was observed at the film/air interface. The thickness of the densified layer increased with both plasma power and plasma exposure time. As a result, up to seven distinct layers were used to model the experimental SXR data from plasma treated films. The FTIR data show that the plasma transforms the Si-H bonds in the HSQ film into Si-O bonds leaving more oxygen atoms around a Si atom. These data are also consistent with the densification observed in the SXR measurements. In general, the HSQ film is more sensitive to increasing plasma power than to increasing plasma exposure time.
Correlations Between Structural Characteristics and Process Conditions of HSQ Based Porous Low-k Thin Films
Authors: Lee Hae-Jeong , Lin Eric K. , Wang Howard , Wu Wen-Li , Chen Wei , Deis Thomas A. 
Published: April 2011

ABSTRACTA novel methodology using a combination of ion scattering, x-ray reflectivity (SXR), and small angle neutron scattering was used to characterize the structure and properties of a hydrogen silsesquioxane (HSQ) based porous low-k dielectric films after varying process conditions. The dielectric constant and the remaining Si-H fraction (degree of cure) of the samples were varied from 1.5 to 2.2 and from 30 % to 52 %, respectively, by controlling the mass ratio of the solvent and the HSQ resin in the initial solutions and the wet ammonia treatment time. We determined the density depth profile, average mass density, wall density, porosity, average pore size, average wall thickness, pore connectivity and atomic composition. The chemical bond structures were also measured using Fourier transform infrared (FTIR) spectroscopy. The density profile of each porous low-k film was uniform and only two layers were required to fit the experimental SXR data. Higher dielectric constant films show significantly higher wall densities and lower porosities and pore sizes. The measured increases in the wall density with lower Si-H fractions are consistent with the FTIR results.
Low Dielectric Constant Functionalized Silica Gels
Authors: Gorman Brian P. , Orozco-Teran Rosa A. , Roepsch Jodi A. , Mueller Dennis W. , Reidy Richard F. 
Published: April 2011

ABSTRACTScaling requirements of the semiconductor industry demand interlayer dielectric materials with low dielectric constants, chemical compatibility with Cu, thermal and mechanical stability, and the capability of integration into planned device structures. We have developed a novel low-k silica gel processing technique capable of both bulk and spin-on film architectures. Derived from fluorinated silica, this gel exhibits very low dielectric constants (1.18 in bulk and 2.1 in thin film measured using AC impedance methods). Structural determination from FTIR illustrates a fluorinated silica structure with shortened Si-O bonds, however, the fluorine is lost after annealing at elevated temperatures. Microstructural analysis by TEM indicate a highly unusual morphology with highly linked features and pore sizes in the 30nm range, coinciding with nitrogen adsorption results. Mechanical properties of the thin films, as studied by nanoindentation methods, shows that the films have extraordinarily high elastic moduli (12GPa) and hardness (1GPa).
Comparative Analysis of the Nucleation and Growth of Copper on Different Low-k Polymers
Authors: Zaporojtchenko V. , Erichsen J. , Strunskus T. , Behnke K. , Faupel F. , Baklanov M. , Maex K. 
Published: April 2011

ABSTRACTIn this work we present investigations of the nucleation and growth of evaporated copper on several low-k polymers. The evolving interfaces were characterized using transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results were compared between the PMDA/ODA polyimide, Teflon AF 1601 and Silk®. A diffusion coefficient for copper atoms in Silk® determined by low energy ion-beam depth profiling in conjunction with XPS is reported.
Highly (111) Oriented Al Thin Films by Ion-Plating Method Using Discharge Plasma
Authors: Masui Shin , Kinoshita Kimio , Sakuragi Susumu , Kudo Toshio , Takayama Shinji 
Published: April 2011

ABSTRACTApplication to aluminum deposition using ion-plating method is described. This method has several superior features for generating highly (111) orientation. The origin of this orientation and surface roughness are discussed in connection with a kinetic energy of the ions. The film properties thus made were compared with those of a conventional sputtered film. The higher (111) oriented film showed high resistance against hillock formation even after annealing at high temperatures. An effect of a plasma cleaning of substrate surface was confirmed to be quite helpful for promotion of (111) preferred orientation.
Bridging Properties of Multiblock Copolymers
Authors: Rasmussen K.Ø. , Kober E. M. , Lookman T. , Saxena A. 
Published: April 2011

ABSTRACTUsing self-consistent field theory, we attempt to elucidate the links between microscopically determined properties, such as the bridging fraction of chains, and mechanical properties of multiblock copolymer materials. We determine morphological aspects such as period and interfacial width and calculate the bridging fractions, and compare with experimental data.
Patterned Deposition from Compressed Carbon Dioxide
Authors: Luscombe C. K. , Huck W. T. S. , Holmes A. B. , Lu T. , Leeke G. A. , Santos R. C. D. , Al-Duri B. , Seville J. P. K. 
Published: April 2011

ABSTRACTCompressed CO2 is employed as the solvent for the deposition of polymers onto patterned surfaces created by a lithographic technique. This deposition technique should have wide applicability in the deposition of organic and polymeric materials for optoelectronic devices. The advantage of controlled deposition confers a further benefit in the control of the patterned surface. In a specific example a perfluorinated polymer was dissolved in liquid carbon dioxide. The polymer solution was deposited by use of a nozzle onto a pre-patterned surface. The resulting polymer film showed a clear image of the original pattern as measured by optical microscopy.
Analysis on the Characteristics of Low-k Benzo-Cyclo-Butene Passivation
Authors: Sul W. S. , Han H. J. , Lee H. S. , Lee B. H. , Kim S. D. , Rhee J. K. 
Published: April 2011

ABSTRACTSurface passivation for the devices is very important for ensuring the DC and RF performances as well as the reliability in pseudomorphic high electron mobility transistors (PHEMT's). We performed the comparative study on the DC, RF and noise characteristics of the 0.1 μm gate length PHEMT's passivated by low dielectric constant benzo-cyclo-butene (BCB) layers with those passivated by the conventional Si3N4 or the. The noise performance of the BCB passivation for the PHEMT's was much superior to that of the Si3N4, whereas the DC and other RF properties were not significantly affected by the passivation materials.