bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nuclear Microprobe Analysis of Transmembrane Ion Flux in Rat Brain
Authors: Briski Karen P. , Hollerman William A. , Glass Gary A. 
Published: April 2011

ABSTRACTMaintenance of euglycemia is crucial because glucose is the sole nutrient that can be utilized by the brain, retina, and germinal epithelium in sufficient quantities to provide required levels of energy. Since carbohydrate reserves in neural tissue are limited, normal nerve cell function depends upon a continuous glucose supply. Neurons located in select brain sites, including the hindbrain nucleus tractus solitarius/area postrema complex (NTS/AP), exhibit unique electrophysiological and/or genomic responses to glucopenia, suggesting that regulatory signaling of this substrate fuel deficit originates within these select loci. Fundamental questions concerning the identification of monitored metabolic variables and the molecular mechanisms by which local sensor cells transduce energetic distributions into neural signals remain unresolved. The combination of microscopic particle induced x-ray emission (μPIXE) and scanning transmission ion microscopy (STIM) can permit quantitative multielemental mapping of the brain, at the single cell level, with part-per-million sensitivity while simultaneously providing structural information. Over the past year, the authors have investigated methods for utilization of μPIXE and STIM in conjunction with established neuroanatomical and pharmacological approaches in a novel strategy to characterize electrolytic indices of neuronal function. Micrometer-scale resolution of discrete brain sites is expected to yield critical information on intracellular levels of ions that regulate membrane potential and synaptic firing. This paper presents results on regional mapping for effects of metabolic manipulations deficits on the transmembrane flux of sodium, potassium, chlorine, and calcium ions. This research will significantly advance the current understanding of the cellular and molecular bases linking neuronal energetics with homeostatic regulation of metabolic substrate availability.
An Investigation of Nano-structured Polymers for Use as Bladder Tissue Replacement Constructs
Authors: Thapa Anil , Webster Thomas J. , Haberstroh Karen M. 
Published: April 2011

ABSTRACTConventionally, studies investigating the design of synthetic bladder wall substitutes have involved polymers with micro-dimensional structures. Since the body is made up of nano-structured components (e.g., extracellular matrix proteins), our focus has been in the use of nano-structured polymers in order to design a three-dimensional synthetic bladder construct that mimics bladder tissue in vivo. In order to complete this task, we fabricated novel, nano-structured, biodegradable materials to serve as substrates for bladder tissue constructs and tested the cytocompatibility properties of these biomaterials in vitro. The results from our in vitro work to date have provided the first evidence that cellular responses (such as adhesion and proliferation) of bladder smooth muscle cells are enhanced as poly (lactic-co-glycolic acid) (PLGA) surface feature dimensions are reduced into the nanometer range.
In situ Mineralization of Hydroxyapatite for a Molecular Control of Mechanical Responses in Hydroxyapatite-Polymer Composites for Bone Replacement
Authors: Katti Kalpana , Gujjula Praveen , Ayyarsamy Arunprakash , Arens Timothy 
Published: April 2011

ABSTRACTIn situ mineralization of hydroxyapatite (HAP) and the role of organics in initial nucleation and growth of HAP is critical for the resulting nano and microstructure of HAP. In situ mineralization of hydroxyapatite (HAP) in the presence of Ca binding polymers such as polyacrylic acid has shown some promise towards improvement of mechanical response of uniaxial compressed HAP/polymer composites to loading. This work represents fundamental studies on the nature of in situ HAP precipitation on resulting microstructure of the composite and bulk mechanical properties. Specifically, an experimental study, evaluating the role of initial stage mineralization of HAP on bulk mechanical responses is conducted. Fourier transform infrared (FT-IR) spectroscopic (with micro attenuated total reflectance) techniques are utilized to evaluate the association of polymer (polyacrylic acid) with HAP during mineralization of HAP. In situ HAP exhibits a faster mineralization as compared to the ex situ mineralization samples, This improved kinetics is responsible for altering the resulting micro and nanostructure of the HAP/polymer composite. Small spectral changes are detected in the absorbance spectra of in situ HAP as compared to ex situ samples. Changes in mechanical response to loading included improvement in strain-to-failure and resulting toughness characteristics of the in situ composite. The control and development of molecular-level associations of polymer with HAP is suggested to be critical for the resulting macro properties. Our results may have significant implications for design of nanocomposites for biomedical applications.
Small Diameter, High Surface Energy Carbon Nanofiber Formulations that Selectively Increase Osteoblast Function
Authors: Price Rachel L. , Elias Kathy L. , Haberstroh Karen M. , Webster Thomas J. 
Published: April 2011

ABSTRACTThe objective of the present in vitro study was to investigate the potential of carbon nanofibers, which have nanometer dimensions similar to hydroxyapatite crystals in physiological bone, for orthopedic applications. Studies of alkaline phosphatase activity and calcium deposition by osteoblasts (the bone-synthesizing cells) were performed on both nanophase (less than 100 nm) and conventional (greater than 100 nm) diameter carbon nanofibers. Results provided the first evidence of a strong correlation between decreased carbon fiber diameter and both increased alkaline phosphatase activity and increased calcium deposition by osteoblasts at early time points (specifically, 7 days), but not at later time points (specifically, 14 and 21 days). Results of early calcium deposition by osteoblasts on carbon nanofibers are promising and consistent with the desired rapid formation of natural bone at the implant interface.
Synchrotron X-ray Observations of a Monolayer Template for Mineralization
Authors: DiMasi E. , Gower L. B. 
Published: April 2011

ABSTRACTMineral nucleation at a Langmuir film interface has been studied by synchrotron x-ray scattering. Diluted calcium bicarbonate solutions were used as subphases for arachidic and stearic acid monolayers, compressed in a Langmuir trough. Self-assembly of the monolayer template is observed directly, and subsequent crystal growth monitored in-situ.
Electroactive Polymerized Vesicles as Stable Biomaterials for Charge Storage Systems and Electron Coupling Applications
Authors: Stanish Ivan , Singh Alok 
Published: April 2011

ABSTRACTDiacetylenic phospholipids with disulfide functionality were synthesized and incorporated at dopant levels with unmodified diacetylenic phosphatidylcholine lipids in polymerized vesicles. These polymerized vesicles were immobilized on Au films and structurally characterized in situ using AFM and ESEM and demonstrated surface stability of at least three days. Polymerized diacetylenic phospholipid vesicles displayed retention of entrapped ferricyanide with a half-life of 2.4 weeks at pH 7 and 25 oC. Membrane-bound benzoquinone mediated electron transport across polymerized vesicle membranes providing an initial current of 25 mA and a final charge capacity based on entrapped ferricyanide of 3.5 Ahr/kg. Electron transport across polymerized diacetylenic phospholipid vesicle membranes was described by a pseudosteady-state transport model and was found to be diffusion limited.
Bio-Inspired Nanocomposites: From Synthesis Toward Potential Applications
Authors: Asefa Tewodros , Coombs Neil , Grondey Hiltrud , Jaroniec Mietek , Kruk Michal , MacLachlan Mark J. , Ozin Geoffrey A. 
Published: April 2011

ABSTRACTIn recent years, the extraordinary properties of bio-inspired nanocomposites have stimulated great interest in the development of bottom-up synthetic approaches to organic-inorganic hybrid materials in which molecular scale control is exerted over the interface between the organic and inorganic moieties. These developments have led to advanced materials with novel properties and potential use in catalysis, sensing, separations and environmental remediation. Periodic mesoporous organosilica (PMO) materials are an entirely new class of nanocomposites with molecularly integrated organic/inorganic networks, high surface areas and pore volumes, and well ordered and uniform size pores and channels. We recently have extended the approach to include novel PMO materials incorporating chiral and heteroatom-containing organic functional groups inside the inorganic framework that may be useful in asymmetric catalysis, enantiomeric separations and heavy metal remediation.
Fib/Tem Analysis of Paint Layers from Thomas Eakins' TheCrucifixion, 1880
Authors: Lins Andrew , Giannuzzi Lucille A. , Stevie Frederick A. , Price Beth , Tucker Mark , Gutman Nica 
Published: April 2011

ABSTRACTMany issues in the examination, treatment, and authentication of works of art depend on the accurate characterization of thin layers, which may challenge the resolution and detection limits of instrumentation routinely used for analyses, particularly SEM-EDS and EPMA. Such thin layers are the focus of recent conservation analysis in preparation for a major retrospective of Thomas Eakins' works. Interpretation of Eakins' paintings has often been complicated by mechanical and chemical cleaning procedures performed after the artist's death in 1916.Recent advances in Focused Ion Beam (FIB) technology provide means for preparing specimens of thin layers that can be analyzed directly by transmission electron microscopy (TEM) yielding resolution in the nanometer range or better. This paper describes initial work undertaken to elucidate the inorganic components in the uppermost paint layers from Eakins' The Crucifixion, completed in 1880. Using TEM, we have observed a 250-500 nm Pb-rich nanocrystalline region, a pigment free zone less than 2 μm thick, and a lead white paint layer. An analysis of samples from two paintings that were subjected to mild cleaning operations did not show comparable Pb-rich nanocrystals. These results suggest that The Crucifixion may have been subjected to a more aggressive cleaning treatment which caused the entrainment of the Pbrich material–not resolvable by traditional analytical techniques – at the painting's surface. The use of FIB/TEM has enabled clear identification of the thin paint surface layers and offers enormous promise for understanding the processing and alteration of artists' materials, including issues of authentication.
The XthCent. Church in Drustar: Study of Wall Paintings by Spectroscopic Methods
Authors: Zorba T. , Paraskevopoulos K.M. , Siapkas D.I. , Pavlidou E. , Angelova S. , Kushev D.B. 
Published: April 2011

ABSTRACTThe technique and painting used in the earlier wall paintings from the characteristic Christian church in Drustar - close to the river Danube - in Bulgaria, are studied. The fragments of wall paintings used in this study are examined mainly by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Analysis (EDS). It is concluded that the technique used was fresco and that the pigments used are common to those used in the Byzantine era.
Simulated Standards for the Characterization of Dolomitic Mortars
Authors: Montoya C. , Lanas J. , Arandigoyen M. , Navarro I. , Casado P.J. García , Alvarez J.I. 
Published: April 2011

ABSTRACTIn order to clarify the structure underlying the appearance of several compounds in dolomitic mortars (specifically hydromagnesite, Mg5(CO3)4(OH)2.4H2O), as well as the suitability of the X-ray diffraction (XRD) and thermogravimetric and thermodifferential simultaneous analysis (TGA-DTA) in their determination, different patterns from phases that could be present in mortars of these characteristics have been prepared and studied by these techniques. The standards were prepared from: hydromagnesite (HY) with calcite in weight/weight proportions 1:1 to 1:5; HY with calcite and quartz in proportions 1:1:1 and 1:6:12; HY with quartz, 1:1 and 1:2; HY with portlandite (calcium hydroxide), 1:1 and 1:2; HY with portlandite and quartz, in 1:6:12, and HY with magnesium oxide in 1:1, 1:2 and 2:1.The XRD results have shown that it is possible to detect HY and the other compounds (dolomite, calcite, magnesite, quartz, …), but when the HY is mixed, the intensity of its diffraction peaks is very weak, even not detectable in some cases. The poor crystallinity of the HY could be the reason of this drop in intensity. Therefore thermal studies were necessary to find HY phases in low weight percentages.TGA-DTA led us to establish the experimental conditions most suitable for thermal studies. A high CO2 pressure around the sample was required for the occurrence of an exothermic peak at 500°C. This high pressure was guaranteed in the present work as follows: static air atmosphere, packed sample, high heating rate (20°C.min-1), and alumina crucibles with holed lids in order to establish a selfgenerated atmosphere. The thermal behavior of hydromagnesite phases has been clearly established in contradiction to some references of the literature; specifically, the exothermic peak at 500°C has been observed repeatedly. This result invalidates reports of the crystallization of magnesium carbonate from the amorphous phase.
Characterization of Ancient Dolomitic Binding Materials from Zamarce, in Navarre (Spain)
Authors: Montoya C. , Lanas J. , Arandigoyen M. , Navarro I. , García Casado P.J. , Alvarez J.I. 
Published: April 2011

ABSTRACTTen ancient mortars of dolomitic origin, used in the construction of the church of Santa María de Zamarce in Navarre, Spain, have been studied in order to define their composition and to characterize the type of binder employed. A complete characterization has been carried out including: morphological examination (visually and using optical microscopy); mineralogical studies (X-ray diffraction, XRD); chemical analysis (main components and soluble salts); grain size distribution and thermal studies (thermogravimetric and thermodifferential simultaneous analysis, TGA-DTA). Dolomite and calcite, as binders, and quartz, as aggregate, have been found as the main phases. The important variability of the studied samples has confirmed that the choice of the raw materials and their preparation were not taken carefully. Thermal behavior of the samples has shown the endothermic peaks related to calcite and dolomite decarbonations. No hydromagnesite phases have been detected. Finally, the approximate indications of the original composition of the raw materials mixtures are presented.
Neutron-induced autoradiography in the study of oil paintings by Tintoretto, Marieschi and Bellotto
Authors: Pańczyk E. , Pytel K. , Kalicki A. , Rowińska L. , Sartowska B. , Waliś L. 
Published: April 2011

ABSTRACTA complex technological investigation of 14th-18th centuries Venetian paintings from the collection of the National Museum in Warsaw has been performed in connection with the “Serenissima- Light of Venice” exhibition. After analysis of the X-ray radiographs of the autoradiography to obtain indisputable information about over-painting (Tintoretto) or either confirmation or contradiction of their authenticity (Marieschi, Bellotto).All the paintings under analysis were irradiated in a specially designed station at the research reactor MARIA in Swierk near Warsaw. Beta-rays emerging from the painting surface irradiated by thermal neutrons and recorded on a X-ray film displayed the distribution of elements in pigments used for creating individual layers of the painting. It allows for tracing the particular phases of the painting structure invisible to the naked eye.The report presents results obtained for the following paintings: J. Tintoretto – Portrait of a Venetian Admiral, M. Marieschi – The palace of Doges in Venice, B. Bellotto called Canaletto – Fantasy architecture with self-portrait of the artist.
A New Method of Restoration and Conservation of Metallic Archeological Objects
Authors: Malkhasyan R. T. , Shakhverdyan R. 
Published: April 2011

ABSTRACTOur method of Quantum - Chemical Technology based on use of strongly non-equilibrium vibrationally highly excited, very active molecules of hydrogen, allows in conditions of low temperature and pressure to realize the direct restoration of the corroded archeological metal-containing objects, without change of their shape and sizes.
A Ghost Story: Remnant Structures in Corroded Ancient Iron Objects
Authors: Notis Michael R. 
Published: April 2011

ABSTRACTThe applicability of a broad spectrum of laboratory analytical methods to the study of remnant structures still observable in the corrosion products of ancient iron objects is discussed. These methods range from examination by light optical microscopy and SEM to direct microanalysis using x-ray mapping in EPMA. Samples ranging from low carbon iron to steels to cast iron have been examined and it has been found possible to observe remnant structures and infer fabrication information from the large majority of objects studied. The author thanks the Nathan Rubin-Ida Ladd Foundation for its support.
Renaissance Enameled Jewelry and 19th century Renaissance Revival: Characterization of Enamel Compositions
Authors: Wypyski Mark T. 
Published: April 2011

ABSTRACTEnamels from European Renaissance enameled gold jewelry and other objects dating from the sixteenth and seventeenth centuries, and Renaissance style and other objects from the eighteenth and nineteenth centuries were quantitatively analyzed using energy dispersive X-ray spectrometry. Differences were observed in the overall compositions, as well as the colorants and opacifiers used, of the Renaissance period and most of the later enamels. Some enamels from as late as the early nineteenth century, however, appeared to be essentially the same as those used during the Renaissance. The differences found in the enamel compositions can provide a set of objective compositional criteria to help distinguish between authentic Renaissance period enameled objects and some later enamels done in the style of the Renaissance.
AMS radiocarbon dating of a Western Han period (3rd-1st century BC) lacquer-coated earthenware jar
Authors: Hodgins G. W. L , Farrell E. , Mowry R. D. 
Published: April 2011

ABSTRACTThe chronometric dating of ceramic objects is normally achieved by thermoluminscence techniques (TL). Here we report both TL and a radiocarbon measurements on a Chinese earthenware hu jar (Harvard University Art Museums LTL1.2001.23 a,b). TL dates were obtained from earthenware core samples using established methods. The radiocarbon date was obtained from an organic coating present on the jar surface. The coating was preliminarily identified as urushi by a comparison of its FTIR absorption spectrum to absorption spectra obtained from modern and ancient lacquer standards. The material was found to be insoluble in a variety of solvents, mineral acids, and bases. Combustion and elemental analysis revealed that 64% of the coating mass was carbon. C measurement by AMS was carried out on a 3.9 mg sample of chemically cleaned lacquer. This measurement generated a date of 2191 ± 38 BP. Calibration of this measurement placed the age of the jar between 390BC and 160 BC at the 95% confidence interval. The calibrated radiocarbon date corroborated the TL measurement placing the jar at between 2400 and 1500 years old (400 BC to 500 AD). These findings also agreed with stylistic evidence that the jar was produced during the Western Han period (206 BC-AD 9). The literature on urushi composition, its pigment compatibility, its high carbon content, its apparent chemical stability, and the small sample required for C-accelerator mass spectrometry suggests that other lacquer-coated objects might be dated using a similar approach.
Investigating Ceramic Technology During Archaeological Field Seasons
Authors: Henrickson Robert C. 
Published: April 2011

ABSTRACTInvestigation of many aspects of ancient ceramic production technologies is feasible during an archaeological field season, and requires little equipment. Descriptive variables such as color, inclusions ( temper ), variable textures within the paste, surface finish, hardness, and decorative techniques and style provide technological as well as stylistic or typological data. Residual surface traces, the surfaces of breaks themselves, and their overall patterning relative to both the vessel shape and size provide forming and finishing data. Subsequent laboratory analysis of samples complements the field data.
The Characterisation of a Bronze Age Weapon Hoard
Authors: Northover J.P. , Bridgford S.D. 
Published: April 2011

ABSTRACTThe study described here is based on the proposition that all events in the life of a bronze artefact, from the moment it was cast to the time it became available for characterisation, have the potential to leave a trace that can be identified by one or more metallographic methods. The hoard presented here was found at Waterden, Norfolk, England by metal detecting and excavation after it was scattered by the plough. The find comprises 201 fragments from approximately 130 swords and spearheads. It is important for understanding the evolution of the Bronze Age sword in Britain, and also for understanding the destruction and deposition of weapons in weapon-only assemblages. Besides a consideration of the hoard from a typological perspective the project used five methods of examination: a) a surface study for manufacturing traces, combat damage, possible cremation, and damage in the ground or at recovery, b) radiography, c) compositional analysis by electron probe microanalysis, d) optical metallography, and e) microhardness testing. This is the first occasion in which these techniques have been combined in the investigation of a complete hoard. It has been possible to divide the results from each technique into simple categories so that clear correlations can be made, so it can be shown that sword blades had more elaborate finishing than others, that some workshops had better casting practice than others and that the great majority of swords had combat damage. The effects of destruction and fire are also discussed and a context for the deposition of the hoard reconstructed.
An Ethnoarchaeological Perspective on the Material and Chemical Residues of Communal Feasting at El Coyote, Northwest Honduras
Authors: Wells E. Christian , Urban Patricia A. 
Published: April 2011

ABSTRACTThis paper examines artifact distributions and chemical analysis of anthropogenic sediments by ICP-AES spectroscopy from the main civic-ceremonial plaza at the Late Classic (ca. AD 700-900) site of El Coyote in northwestern Honduras. Based on ethnoarchaeological comparisons drawn from a phosphate study of plaza soils in the nearby modern-day town of Petoa, spatial aspects of the organization of communal feasting are inferred for El Coyote.