bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biomarkers of Oxidative Damage in Human Disease
Authors: Dalle-Donne Isabella , Rossi Ranieri , Colombo Roberto , Giustarini Daniela , Milzani Aldo 
Published: February 2006

AbstractOxidative/nitrosative stress, a pervasive condition of increased amounts of reactive oxygen/nitrogen species, is now recognized to be a prominent feature of many acute and chronic diseases and even of the normal aging process. However, definitive evidence for this association has often been lacking because of recognized shortcomings with biomarkers and/or methods available to assess oxidative stress status in humans. Emphasis is now being placed on biomarkers of oxidative stress, which are objectively measured and evaluated as indicators of normal biological processes, pathogenic processes, or pharmacologic responses to therapeutic intervention. To be a predictor of disease, a biomarker must be validated. Validation criteria include intrinsic qualities such as specificity, sensitivity, degree of inter- and intraindividual variability, and knowledge of the confounding and modifying factors. In addition, characteristics of the sampling and analytical procedures are of relevance, including constraints and noninvasiveness of sampling, stability of potential biomarkers, and the simplicity, sensitivity, specificity, and speed of the analytical method. Here we discuss some of the more commonly used biomarkers of oxidative/nitrosative damage and include selected examples of human studies.
Crystal structure of new lanthanide diphosphates KLnP2O7 · 2 H2O (Ln = Gd, Tb, Yb)
Authors: Tahiri Aziz A. , El Bali Brahim , Lachkar Mohammed , Piniella Juan F. , Capitelli Francesco 
Published: February 2006

Abstract
Crystals of lanthanide diphosphates KLnP2O7 · 2 H2O [Ln = Gd, Tb, Yb] have been synthesized and investigated by single-crystal X-ray diffractometry. The three structures resulted to be isostructural within monoclinic space group P21/c, with unit cell parameters of a = 7.7522(2) Å, b = 10.6732(8) Å, c = 10.1375(7) Å, β = 93.308(5)°, V = 837.39(9) Å3 (KGdP2O7 · 2 H2O = (1)), a = 7.7380(6) Å, b = 10.6360(8) Å, c = 10.1060(7) Å, β = 93.283(6), V = 830.37(11) Å3 (KTbP2O7 · 2 H2O = (2)), a = 7.6791(3) Å, b = 10.4992(7) Å, c = 9.9554(9) Å, β = 93.214(6)°, V = 801.39(10) Å3 (KYbP2O7 · 2 H2O = (3)). The three-dimensional frameworks are made by zig-zag chains of KO9 irregular polyhedra down c, sharing vertices with LnO7 polyhedra and P2O7 units; intricate hydrogen bonding networks complete the arrays.
Effect of hydrostatic pressure on the crystal structure of sodium oxalate: X-ray diffraction study and ab initio simulations
Authors: Boldyreva Elena V. , Ahsbahs Hans , Chernyshev Vladimir V. , Ivashevskaya Svetlana N. , Oganov Artem R. 
Published: February 2006

Abstract
Effect of hydrostatic pressures up to 8 GPa on the crystals of Na2C2O4 (sp. gr. P21/c) was studied in situ in the diamond anvil cells a) in neon, b) in methanol-ethanol mixture by high-resolution X-ray powder diffraction (synchrotron radiation, λ = 0.7 Å, MAR345-detector). Below 3.3–3.8 GPa, anisotropic structural distortion was observed, which was similar to, but not identical with that on cooling. At 3.8 GPa, a reversible isosymmetric first-order phase transition without hysteresis occurred. The orientation of the oxalate anions changed at the transition point by a jump, and so did the coordination of the sodium cations by oxygen atoms. Ab initio simulations based on the generalized gradient approximation of density functional theory have reproduced the main features of the structural changes in the crystals of sodium oxalate with increasing pressure. The theoretical pressure for the isosymmetric phase transition is 3.65 GPa, close to the experimental value; in agreement with experiment the transition was predicted to be reversible. Ab initio calculations gave a pronounced hysteresis for this transition, and have also predicted a further isosymmetric phase transition at 10.9 GPa, also with a hysteresis. The role of temperature in the pressure-induced phase transitions in sodium oxalate is discussed.
Ion Channels in Mesenchymal Stem Cells from Rat Bone Marrow
Authors: Li Gui-Rong , Deng Xiu-Ling , Sun Haiying , Chung Stephen S.M. , Tse Hung-Fat , Lau Chu-Pak 
Published: February 2006

AbstractMesenchymal stem cells (MSCs) from bone marrow are believed to be an ideal cell source for cardiomyoplasty; however, cellular electrophysiology is not understood. The present study was designed to investigate ion channels in undifferentiated rat MSCs. It was found that three types of outward currents were present in rat MSCs, including a small portion of Ca2+-activated K+ channel (IKCa) sensitive to inhibition by iberiotoxin and/or clotromazole, a delayed rectifier K+ current (IKDR), and a transient outward K+ current (Ito). In addition, tetrodotoxin (TTX)-sensitive sodium current (INa.TTX) and nifedipine-sensitive L-type Ca2+ current (ICa.L) were found in a small population of rat MSCs. Moreover, reverse transcription-polymerase chain reaction revealed the molecular evidence of mRNA for the functional ionic currents, including Slo and KCNN4 for IKCa; Kv1.4 for Ito; Kv1.2 and Kv2.1 for IKDR; SCN2a1 for INa.TTX; and CCHL2a for ICa.L. These results demonstrate for the first time that multiple functional ion channel currents (i.e., IKCa, Ito, IKDR, INa.TTX, and ICa.L) are present in rat MSCs from bone marrow; however, physiological roles of these ion channels remain to be studied.
Prospective Isolation of Murine Hematopoietic Stem Cells by Expression of an Abcg2/GFP Allele
Authors: Tadjali Mehrdad , Zhou Sheng , Rehg Jerold , Sorrentino Brian P. 
Published: February 2006

Abstract
Stem cells from a variety of tissues can be identified by a side population (SP) phenotype based on Hoechst 33342 dye efflux. The Abcg2 transporter is expressed in hematopoietic stem cells (HSCs) and confers this dye efflux activity. To further explore the relationship among Abcg2 expression, the SP phenotype, and HSC activity, we have generated mice in which a green fluorescent protein (GFP) reporter gene was inserted into the Abcg2 locus. In these mice, the majority of bone marrow (BM) cells that expressed the Abcg2/ GFP allele were Ter119+ erythroid cells. The Abcg2/GFP allele was also expressed in approximately 10% of lineage-negative (Lin−) and in 91% of SP cells using stringent conditions for the SP assay. Flow cytometric sorting was used to isolate various Abcg2/GFP+ BM cell populations that were then tested for HSC activity in transplant assays. There was significant enrichment for HSCs in sorted Lin−/ GFP+ cells, with a calculated HSC frequency of approximately one in 75. There was no HSC activity detected in Lin−/GFP+ cells. Altogether, these results show that Abcg2 is expressed on essentially all murine BM HSCs and can be used as a prospective marker for HSC enrichment.
Phosphorus Compounds
Authors: Fee Darrell C. , Gard David R. , Yang Chen‐Hsyong 
Published: February 2006

AbstractPhosphorus compounds exhibit an enormous variety of chemical and physical properties as a result of the wide range in the oxidative states and coordination numbers for the phosphorus atom. The intermediate electronegativity of phosphorus also plays a role. Phosphorus oxides, halides, sulfides, hydrides (phosphines), nitrogen compounds, and metal phosphides, as well as organophosphorus compounds, are reviewed. Emphasis is placed on the commercially important phosphorus trichloride, phosphorus pentachloride, phosphorus pentasulfide, phosphorus (V) oxide, and phosphine. Structure and nomenclature of phosphorus compounds and their organic derivatives are presented. Properties of the PO, PS, PH, PC, and PX (X = halogen) bonds are given. The manufacture of the commercial phosphorus compounds is outlined. Phosphorus compounds are found in or used as intermediates for the manufacture of oil additives, heat‐transfer and hydraulic fluids, water‐treatment chemicals, catalysts, herbicides, flame retardants, pesticides, pharmaceuticals, semiconductors, and surfactants. Intermediates in the preparation of organophosphorus derivatives are reviewed.
Smart Materials
Authors: Wilson Alan Richard 
Published: February 2006

Abstract
The field of smart materials is extremely large and probably includes representatives from all types of materials. The term, “smart material”, has some confusion attached to it as to what it actually means. A critical defining element for a material to qualify as “smart” is for it to have the ability to respond to a stimulus in a useful way, in an engineering sense, this response being both timely and in a controlled manner. Otherwise, all materials could be considered to be smart since all materials respond to external stimuli in same way. The discriminating factor is whether this response can be harnessed for some useful purpose. Stimuli may include mechanical deformation, stress and pressure, temperature, chemicals, incident radiation, electric and magnetic fields, electric current and charges, and other stimuli. Material responses to these types of stimuli include the rearrangement of atomic and molecular structures, the creation and motion of crystallographic defects or other local conformations, absorption of and emission of photons, chemical reactions, generation of charge and voltage, and other effects. Smart materials are most often reversible in nature with the stimulus and response being interchangeable actions.
This article includes examples of materials with piezoelectric, ferroelectric, shape memory, electrostrictive, magnetostrictive, electrorheological, magnetorheological, photo responsive, and sensitive and chemically and biochemically responsive properties. Some particular classes of materials are also considered including, conducting polymers, electroactive polymers, semiconductor films, metal oxides, nanotechnology (including carbon nanotubes), and smart catalysts.
Zinc and Zinc Alloys
Authors: Goodwin Frank E. 
Published: February 2006

AbstractZinc is a relatively active metal and its compounds are stable. Since it is not found free in Nature, it was discovered later than less‐reactive metals. The main application of zinc is to protect iron and other metals from corrosion. Occurrence and properties of zinc are discussed. Processing of the ore requires concentration of the ore followed by roasting, or reduction by electrolytic methods. Economic data, specifications and grades, health and safety factors are given. The uses of zinc coatings on iron and steel are described as die‐casting alloys and foundry alloys. Rolled zinc and zinc dust and powder also find industrial use. Ores exploited for zinc invariably contain one or more other valuable metals, such as cadmium and mercury.
Zinc Compounds
Authors: Goodwin Frank E. 
Published: February 2006

Abstract
Zinc usually occurs as the sulfide, but significant quantities of the oxide, carbonate, silicate, and basic compounds of the latter two are mined. Properties of many of the compounds of zinc are given, with special attention given to zinc oxide, zinc chloride, and zinc sulfate. The oxide is important because it completely absorbs ultraviolet light < 366 nm and it is unique among white pigments. In glass, zinc oxide reduces the thermal coefficient of expansion and improves stability against deformation under stress. Details on the American (Direct) process and French (Indirect) Process for the production and processing of zinc are given as well as a discussion of secondary zinc oxide obtained from scrap. Zinc is needed for the proper functioning of plants and animals and this is discussed along with health and safety aspects, uses, and economics.
Predictors of glass transition in the biodegradable poly‐lactide and poly‐lactide‐co‐glycolide polymers
Authors: In Pyo Park Peter , Jonnalagadda Sriramakamal 
Published: February 2006

AbstractThe biodegradable polylactide (PLA) and polylactide‐co‐glycolides (PLGAs) are being widely investigated for use as scaffolds in bone and ligament reconstruction. The glass transition temperatures (Tg) for these polymers are generally greater than 37°C, causing PLA and PLGA devices to possess brittle characteristics in physiological conditions. To evaluate the possibility of obtaining PLGA polymers with Tg values below 37°C, we evaluated the determinants of Tg in PLA and PLGA copolymers. The Tg, changes in specific heat capacity (ΔCp), and enthalpic relaxation (ΔHg) in two consecutive heating cycles were correlated with lactide/glycolide content and intrinsic viscosity [η] for PLA, PLGAs 90:10, 75:25, 65:35, and 50:50. A linear correlation was observed between Tg and intrinsic viscosity, with 0.1 dL/g increase in viscosity resulting in an increase in Tg by about 3.55°C. The selection of PLA and PLGA copolymers with [η] values <0.19 dL/g, corresponding to a viscosity average molecular weight of <70 kDa, will obtain PLA/PLGA polymers with Tg values below 37°C. The lowest attainable Tg values were found to be 28–30°C. Intrinsic viscosity also correlated with ΔCp differences between aged and rapidly cooled polymers, and is therefore important in predicting free volume changes within these polymers upon aging. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1983–1987, 2006
Thermally initiated cationic polymerization and properties of epoxy siloxane
Authors: Morita Yasumasa , Tajima Seitarou , Suzuki Hiroshi , Sugino Hiroaki 
Published: February 2006

AbstractDifunctional epoxy siloxane monomers containing disiloxane, trisiloxane, and tetrasiloxane were prepared by hydrosilylation of an α,ω‐difunctional SiH‐terminated siloxane with a vinyl‐functional epoxide. Cationic polymerization of these monomers using 3‐methyl‐2‐butenyltetramethylenesulfonium hexafluoroantimonate and their reactivities were examined. The reactivity order was disiloxane > trisiloxane > tetrasiloxane. Thermal discoloration of these polymers increased with catalyst concentration and also with the length of dimethyl siloxane. UV discoloration was also accelerated by catalyst. From the thermo gravimetric analysis, it was found that the thermal stabilities of polymers increased with increasing the length of dimethyl siloxane chain. Mechanical properties of polymers were also tested by thermal mechanical analysis and dynamic mechanical analysis, and it was found that the flexibility of polymers was increased with increasing siloxane chain length. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2010–2019, 2006
Postspinning draw of polymeric fibers: Multiscale micromechanical model for a solid polymer under finite deformation and strain‐induced crystallization
Authors: Makradi A. , Cox C. L. , Ahzi S. , Belouettar S. 
Published: February 2006

AbstractA polymeric fiber postspinning draw model is developed. The fiber is stretched between the take‐up roll and the draw roll and then relaxed between the draw roll and the relax roll. The behavior of the polymeric material is described by a cooperative elastic–viscoplastic model for a wide range of temperatures and strain rates. The profiles of the fiber velocity, stress, strain rate, and temperature between the different rolls are simulated via the coupling of the cooperative model with the mass, momentum, and energy equations and the boundary conditions. Simulations are conducted with the finite‐element method. The computed results show an increase in the fiber stress between the take‐up roll and the draw roll due to the molecular orientation and the increase in the crystallization percentage. The sliding distance of the fiber on the draw roll is related to the draw ratio and fiber stiffness. A dramatic drop in the fiber strain rate on the draw roll leads to relaxation of the intermolecular resistance followed by a freeze of the fiber structure when the strain rate vanishes to zero on the draw roll and between the draw roll and the relax roll. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2259–2266, 2006
Thermoplastic elastomeric nanocomposites from poly[styrene–(ethylene‐co‐butylene)–styrene] triblock copolymer and clay: Preparation and characterization
Authors: Ganguly Anirban , De Sarkar Mousumi , Bhowmick Anil K. 
Published: February 2006

AbstractThermoplastic elastomer (TPE)–clay nanocomposites based on poly[styrene–(ethylene‐co‐butylene)–styrene] triblock copolymer (SEBS) were prepared. Natural sodium montmorillonite (MMT) clay was organically modified by octadecyl amine to produce an amine‐modified hydrophobic nanoclay (OC). Commercially available Cloisite 20A (CL20) and Cloisite 10A, tallow ammine modified nanoclays, were also used. The intergallery spacing of MMT increased on amine modification as suggested by the shifting of the X‐ray diffraction (XRD) peak from 7.6 to 4.5 and 3.8° in the cases of OC and CL20, respectively. The latter demonstrated no XRD peak when it was used at 2 and 4 parts phr in the SEBS system. Transmission electron microscopy studies showed the intercalation–exfoliation morphology in SEBS containing 4 parts of CL204–SEBS, agglomeration in SEBS having 4 parts of MMT, and mixed morphology in SEBS with 4 parts of OC systems. Locations of the clay particles were indicated by the atomic force micrographs. Mechanical and dynamic mechanical thermal analysis studies confirmed the best properties with the CL204–SEBS nanocomposites. Significant improvements in mechanical properties such as tensile strength, modulus, work to break, and elongation at break were achieved with the CL204–SEBS in polymer‐layered silicate nanocomposites. Dynamic mechanical studies further showed the affinity of the organoclays toward both segments of the TPE and a compatibilization effect with CL20 at a 4‐phr loading. Atomic force microscopy showed distinctly different morphologies in nanocomposites prepared through solution and melt processing. Comparisons of the mechanical, dynamic mechanical, and morphological properties of the nanocomposites prepared by melt and solution intercalation processes were done. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2040–2052, 2006
Preparation and properties of polyimide/silica hybrid composites based on polymer‐modified colloidal silica
Authors: Im Ji‐Sun , Lee Ju‐Hyung , An Seung‐Kook , Song Ki‐Won , Jo Nam‐Ju , Lee Jang‐Oo , Yoshinaga Kohji 
Published: February 2006

AbstractA new type of polyimide/silica (PI/SiO2) hybrid composite films was prepared by blending polymer‐modified colloidal silica with the semiflexible polyimide. Polyimide was solution‐imidized at higher temperature than the glass transition temperature (Tg) using 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 4,4′‐diaminodiphenyl ether (ODA). The morphological observation on the prepared hybrid films by scanning electron microscopy (SEM) pointed to the existence of miscible organic–inorganic phase, which resulted in improved mechanical properties compared with pure PI. The incorporation of the silica structures in the PI matrix also increased both Tg and thermal stability of the resulting films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2053–2061, 2006
Study of morphology influence on rheological properties of compatibilized TPU/SAN blends
Authors: Ulcnik‐Krump M. 
Published: February 2006

AbstractThe compatibilizing efficiency of three different compatibilizers on the thermoplastic polyurethane/styrene‐co‐acrylonitrile (TPU/SAN) blends properties was investigated after compatibilizer's incorporation via melt‐mixing. The compatibilizers studied were as follows: poly‐ε‐caprolactone (PCL) of different molecular weight (Mw), a mixture of polystyrene‐block‐polycaprolactone (PS‐b‐PCL) and polystyrene‐block‐poly (methyl methacrylate) (PS‐b‐PMMA), and a mixture of polyisoprene‐block‐polycaprolactone (PI‐b‐PCL) and polybutadiene‐block‐poly (methyl methacrylate) (PB‐b‐PMMA). In our study, the effect of 5 wt % added compatibilizers on TPU/SAN blends morphology was examined. The transmission electron microscopy (TEM) was used to study the morphology at different length scales and to determine the compatibilizer's location. Investigations showed the different improvement of properties, because of the different incorporation of compatibilizers in the polymer blend. The morphology influence on the rheological behavior of compatibilized blends was investigated with a stress‐controlled rheometer (Rheometric Dynamic Stress Rheometer, SR‐500). Different compatibilization activity was found for different system. It was also found that compatibilization activity of added compatibilizer strongly depends on the comaptibilizer'sMw. Blends compatibilized with PCL showed superior properties as compared with the other examined blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2303–2316, 2006
Ultraviolet curable dry polymer films from emulsion polymers
Authors: Chee Swee Yong , Gan Seng Neon 
Published: February 2006

AbstractLow levels of functional acrylic monomers were incorporated into a core‐shell acrylic copolymer by seeded emulsion polymerization. The increase in glass transition temperature, Tg, from DSC measurement has showed that although certain amount of crosslinking reactions have occurred during the polymerization and isolation of the copolymer, the dried copolymer films could undergo further curing by UV irradiation. The structure and amount of the functional monomer, concentration of photoinitiator, and the extent of UV exposure have exerted significant influence on the Tg of the dry copolymer films. Because of the relatively low level of incorporated unsaturation, there was no significant change in FTIR during the curing of the film. Further, crosslinking of the copolymer film induced by UV irradiation has significantly increased the resistance to swelling in alkaline solution, although the gel content remained the same. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2317–2322, 2006
Synthesis and characterization of photo‐crosslinkable polyfluorene with acrylate side‐chains
Authors: Wu Guanglong , Yang Chunhe , Fan Benhu , Zhang Bin , Chen Xiaomin , Li Yongfang 
Published: February 2006

AbstractA photo‐crosslinkable polymer, poly[2,7‐(9,9‐dioctylfluorene)‐co‐2,7‐(9‐hexyl‐9‐(2‐acrylate ethyl)‐9H‐fluorene)] (P3), was synthesized and the photo‐crosslinkable acrylate groups were introduced into the side‐chains of the polyfluorene derivative after its polymerization. This method avoids the possible crosslinkage of the crosslinkable groups on the monomers during polymerization in the traditional synthesis route by the polymerization of the monomers with the crosslinkable side‐chains. The soluble and processable polymer P3 could be crosslinked via the acrylate groups in its side‐chains upon exposure to UV light in nitrogen atmosphere. The crosslinking was confirmed by IR spectroscopy: the IR peak of CC bond at 1635 cm−1 decreased and that of the vinyl CH bond at 742 cm−1 disappeared after the UV exposure. The absorption spectra of P3 remain unchanged after crosslinking, but a longer wavelength emission at 517 nm appeared in the photoluminescent and electroluminescent spectra of the crosslinked P3, which could be attributed to the formation of keto defects during the photo crosslinking. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2336–2342, 2006
Mass transfer of dilute 1,2‐dimethoxyethane aqueous solutions during pervaporation process
Authors: Liang Liang , Dickson James M. , Jiang Jianxiong , Brook Michael A. 
Published: February 2006

AbstractPervaporation of 1,2‐dimethoxyethane (1,2‐DME) is evaluated by crosslinked oligosilylstyrene–poly(dimethylsiloxane) composite membranes. A low flow velocity of the feed solution (1.0 L/min), corresponding to a Reynolds number of 220, is used. The pervaporation models are developed by combining the resistance in series and solution–diffusion models. The effects of the boundary layer on the performance of pervaporation are estimated by comparing experimental and theoretical data. The permeation fluxes of 1,2‐DME and water fit very well with the calculated data from the models, but a deviation of the separation factor between the experimental and theoretical data is observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:2075–2084, 2006