bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensors and sensor arrays based on conjugated polymers and carbon nanotubes
Authors: Dai Liming , Soundarrajan Prabhu , Kim Taehyung 
Published: October 2007

Abstract
The need for cheaper, faster, and more accurate measurements has been a driving force for the development of new sensing devices. As is well known, the electrical conductivity of conjugated polymers can be reliably regulated over a wide range through interactions with electron acceptors and donors. This, together with the fast optical dynamics (either in the ground or excited states) of most conjugated polymers, has made conjugated polymers very attractive as transducer-active materials. On the other hand, the unusual electronic, mechanical, and thermal properties of carbon nanotubes have also led to their potential use in a wide range of devices, including sensors. In particular, the ability of carbon nanotubes and their derivatives to operate as gas and glucose sensors has been recently demonstrated. This article provides a status review on the research and development of sensors and sensor arrays based on conjugated polymers and carbon nanotubes. The unique features characteristic of most reported sensing transduction modes related to conjugated polymers and carbon nanotubes are discussed, along with their pros and cons.
Solubility and crystallization in biological fluids and the problems of life and health
Authors: Gutzow I. , Atanassova S. , Neykov K. 
Published: October 2007

Abstract
An analysis is given of several biologically important processes, connected with the crystallization and kinetics of liophilization in aqueous physiological solutions. These are glass formation and vitrification of life, precipitation of slightly soluble salts and kinetics of crystallization in human urine, and the solution of CaOX concretions under the influence of biocompatible solubilizators, which are normal constituents of human urine. The problems investigated experimentally are treated in the framework of the capillary theory of nucleation and the Debye–Hückel model of ionic solutions.
Calculation of the free Gibbs energy of phase transitions using solubility data. 1. The system Na2SO4-Na2Se04-H2O at 15 °C: Stable and metastable
Authors: Balarew Chr. 
Published: October 2007

Abstract
The solubility isotherms of the systems Na2SO4 ·10H2O–Na2SeO4·10H2O–H2O and Na2SO4·7H2O–Na2SeO4 ·7H2O–H2O have been investigated at 15 °C. It is established that discontinuous series of mixed crystals are formed in both systems. Two methods of calculation of the free Gibbs energy of phase transition at the interruption point of the solubility diagrams are used: (i) on the basis of the composition of the two mixed crystal types, which are in equilibrium with the saturated solution in the eutonic point of the system, and (ii) from the distribution coefficients between each of the mixed crystal phases and their saturated solution, using both experimentally obtained values and calculated distribution coefficients for ideal isomorphic mixing. The data found by the two methods exhibit very good agreement. It is established that the free Gibbs energy of the phase transition in the case of decahydrates is lower than in the case of heptahydrates. This fact is considered as a confirmation of the buffering action of water molecules with respect to the distortion of the crystal structures of the pure salts provoked by the formation of mixed crystals.
Nonlinear mass transfer and hydrodynamic stability in solubility phenomena
Authors: Bojadjiev Chr. 
Published: October 2007

Abstract
The dissolution of gases, liquids,or solids in liquids is a heterogeneous reaction, and in many cases, the reaction rate is limited by a diffusive transfer of substance in the boundary layer at the face interphase. In modern industry, intensive interphase mass transfer processes are accomplished by large concentration gradients. This can result in a set of nonlinear effects and the difference between experimental data and predictions of the linear mass transfer theory. One of the main nonlinear effects is a result of the induction of a secondary flow at the interface boundary. This can lead to essential changes of the dissolution rate and the hydrodynamic stability of the system.
New mechanism for the dissolution of sparingly soluble minerals
Authors: Tang Ruikang , Nancollas George H. 
Published: October 2007

Abstract
A requirement for the determination of the solubility of minerals is to ensure that equilibrium has been reached. Recent constant composition dissolution studies of sparingly soluble calcium phosphates have revealed an interesting and unusual behavior in that the rates decreased, eventually resulting in effective reaction suppression, even though the solutions remained undersaturated. Traditional theories of dissolution assume a volume diffusion-controlled mechanism with reaction continuing until true equilibrium has been reached. The new results for sparingly soluble salts point to the importance not only of particle size on the dissolution rate but also the participation of critical phenomena. Although the crystal size decreases during dissolution, when the reaction is controlled by poly-pitting (the formation and growth of pits), the edge free energy increases at the very first stage of reaction owing to the creation of pits and dissolution steps. The constant composition experimental results demonstrate the development of surface roughness as the dissolution steps are formed, implying an increase of the total edge length during the reaction. This is an exactly analogous mechanism to that of crystal growth, in which the formation of embryos of critical size plays a key role in the overall mechanism. In contrast to crystal growth, dissolution is a process of size reduction, and, when the particle size is sufficiently reduced, critical phenomena become important so that the influence of size must be taken into consideration. It is interesting to recognize that these critical phenomena are readily apparent for sparingly soluble minerals for which the critical conditions are attained much more readily. The results point to the importance of understanding the detailed mechanism of dissolution when attempts are made to measure, experimentally, the solubilities of sparingly soluble minerals.
Structural investigation of water and aqueous solutions by Raman spectroscopy
Authors: Rull F. 
Published: October 2007

Abstract
In the context of a long study of the dynamical properties of water and inorganic aqueous solutions using infrared (IR) and Raman spectroscopy,we present here recent results of the influence of salt concentration on the dynamics of water molecules. The main systems studied were salts of XnYm
type (where X = Li+, Na+, K+, Rb+, Cs+, Mg2+, Zn2+ and Y = Cl–,ClO4
–, NO3
–, SO4
–2).
The whole spectrum reflects the molecular and ionic interactions between solvent molecules and solvent–solute and solute–solute molecules. Nevertheless, each spectral region supplies different information about these intermolecular interactions.
The strong modifications in intensity and band profile undergone by the v(OH) band depends mainly on the nature of anions while cations have a weak influence. A picture of these different situations in a particular salt solution needs the support of a model of the dynamic structure of the water solvent. A discussion of the current state of the dynamical models of liquid water and new ideas on water dynamics are presented on the basis of the results obtained from the study of internal OH/OD vibrations of water in diluted mixtures of D2O/H2O.
Finally, a comparative analysis of the influence on the dynamics of water molecules under the concentration of perchlorate and chloride salts of monovalent cations in water and isotopic D2O/H2O mixtures was undertaken using Raman spectroscopy.
Derivation of complete phase diagrams for ternary systems with immiscibility phenomena and solid–fluid equilibria
Authors: Valyashko V. M. 
Published: October 2007

Abstract
Four main types of binary fluid-phase diagrams and available experimental data on binary systems are used as a starting point for derivation of the systematic classification of binary complete phase diagrams by the method of continuous topological transformations. This method and the classification of binary phase diagrams, containing the boundary versions of phase diagrams with ternary nonvariant points, are applied to derive the main types of fluid and complete phase diagrams for ternary systems with one volatile component and immiscibility phenomena in two constituent binary subsystems. The results gained from this analysis of derived fluid and complete phase diagrams of ternary systems are represented.
Nomenclature of regular single-strand organic polymers (IUPAC Recommendations 2002)
Authors: Kahovec J. , Fox R. B. , Hatada K. 
Published: October 2007

Abstract
A structure-based nomenclature for regular single-strand organic polymers is described. In concept, a generic name for the polymer (ABC)
n
is poly(ABC), in which (ABC) is a constitutional repeating unit (CRU) representing the chemical structure of the polymer chain, and A, B, and C are the subunits that comprise the CRU. To provide a unique and unambiguous name, rules are given to identify the preferred CRU and to name it using the names of A, B, and C based on current organic nomenclature. Provisions are made for naming end-groups of the polymers and the polymer substituents. In addition, the document contains a glossary of concepts and definitions, a list of common subunit names, and a variety of examples of structure-based polymer names. The document is a revision of the 1975 Rules.
Natural and synthetic substances related to human health (IUPAC Technical Report)
Authors: Topliss J. G. , Clark A. M. , Ernst E. , Hufford C. D. , Johnston G. A. R. , Rimoldi J. M. , Weimann B. J. 
Published: October 2007

Abstract
There is a widespread belief on the part of the general public that natural substances are inherently superior to synthetic substances with regard to efficacy and safety in matters related to human health. This question is examined by reviewing the therapeutic use of drugs and herbal medicine preparations, the role of vitamins and nutrients, and the effects of toxic substances. A comparison of the characteristics of natural and synthetic substances within these categories shows a similar range of favorable and unfavorable effects. It is apparent that molecular structure and dose determine the effect of substances on human health, not whether they are of natural or synthetic origin.
ABCG subfamily of human ATP-binding cassette proteins
Authors: Lorkowski Stefan , Cullen Paul 
Published: October 2007

Abstract
ATP-binding cassette (ABC) proteins form one of the largest known protein families and have been found in all known organisms. Most members of the human ABC protein family are membrane-spanning transporters that use energy derived from the hydrolysis of ATP to transport specific substrates across cell membranes. Mutations in certain human ABC transporters of the subfamilies A, B, C, and D have been shown to cause a wide variety of inherited diseases such as the lung condition cystic fibrosis, the nervous degenerative condition adrenoleukodystrophy (of Lorenzo’s Oil fame), hereditary macular degeneration of the eye (Stargardt’s disease), and inherited deficiency of circulating high-density lipoproteins (Tangier disease or familial hypoalphalipoproteinemia). Very recent studies showed that mutations in two members of the subfamily G of human ABC transporters (ABCG5 and ABCG8) cause a condition called sitosterolemia in which plant sterols accumulate in the body and may be responsible for influencing total body sterol homeostasis. In addition, other members of the subfamily G, namely ABCG1 and ABCG4, have also been shown to be involved in cellular lipid trafficking and are thought to play important roles during foam cell formation of human macrophages. By contrast, ABCG2 is a multidrug resistance transporter.
In this review, we focus on the current knowledge and physiological background of the members of the subfamily G. We also present new insights on the evolutionary relationship of human and nonhuman ABCG proteins.
Thick films of ceramic superconducting, electro-ceramic materials
Authors: Altenburg H. , Plewa J. , Plesch G. , Shpotyuk O. 
Published: October 2007

Abstract
The use of thick films becomes more and more important in particular for electronic and microelectronic applications. The term “thick film ” does not relate so much to the thickness of the film but more to the kind of deposition. Thick films are made by low-priced processes such as doctor (dr) blading, screen-printing, or spraying methods, etc. The preparation of thick films of ceramic material by these methods generally implies a processing sequence of the following steps: preparation of the oxide powders; preparation of pastes and slurries; painting/printing, etc.of the pastes onto a suitable substrate; drying at low temperature; and sintering at high temperature to get a consolidated layer. These technologies and the fabricated thick films of thermoresistive and superconducting materials will be discussed.
Catalyic conversion of hydrocarbons in zeolites from first principles
Authors: Benco Ľubomír , Demuth Thomas , Hutschka François 
Published: October 2007

Abstract
The application of the density functional techniques to processes of the conversion of hydrocarbons in zeolites has been reviewed. The conversion of hydrocarbons over zeolites is an important industrial process. The microscopic steps of the conversion, however, are still not satisfactorily understood. In order to examine reaction pathways, both static and molecular dynamics density functional theory (DFT) calculations have been performed. Simulated structural and spectral properties compare reasonably with experimental data. Comparison of energies of physisorption and chemisorption indicates possible reaction channel of the conversion through the chemisorption at the specific O-sites of the zeolite.
Nonvacuum-based deposition techniques for superconducting ceramic coatings
Authors: Van Driessche I. , Penneman G. , Bruneel E. , Hoste S. 
Published: October 2007

Abstract
The widespread use of vacuum-based techniques for the deposition of ceramic coatings with specific electric, magnetic, optical, and mechanical properties is well established in the research environment, and some of them have been implemented in a variety of industrial processes. However, obtaining uninterrupted deposition at high speed, increasing flexibility in composition and in film thickness, and attaining independence of geometric constraints are areas in which many vacuum techniques will need sustained development in order to answer industrial demands. The development of the next generation of deposition methods, which could alleviate some of these shortcomings and which are based on deposition under atmospheric environment and from aqueous precursor materials, is a real challenge for the community of solid-state chemists and delineates the subject of this overview.
Silicon-based ceramics from polymer precursors
Authors: Interrante Leonard V. , Moraes K. , Liu Q. , Lu N. , Puerta A. , Sneddon L. G. 
Published: October 2007

Abstract
A hyperbranched polycarbosilane of the type [R3SiCH2−]
x
[−SiR2CH2−]
y
[−SiR(CH2−)1.5]
z
[−Si(CH2−)2]
l
(R = H, –CH2CH=CH2, or OR) has been prepared, which was used as a source of inorganic/organic hybrid materials and, through pyrolysis, as a precursor to inorganic solids with unusual microstructures and properties. A partially allyl-substituted derivative “AHPCS”, nominally ['Si(allyl)0.1H0.9CH2']
n
, has been extensively studied as a precursor to silicon carbide (SiC) and is now used commercially as a SiC matrix source for C- and SiC-fiber-reinforced composites and binder for particulate ceramics. The alkoxy derivatives, ['Si(OR)2CH2'], (R = Me, Et) yield, after hydrolysis and condensation, carbosilane/siloxane gels with unusually high surface areas (700–900 m2/g) and microporosity that is retained in the resultant SiOxCy ceramics formed after pyrolysis to 1000 °C. The fully condensed ['Si(O)CH2'] gel in the latter case was obtained as thin, adherent films on Si surfaces by spin coating and was found to exhibit dielectric constants as low as 2.0 after heating to 400 °C. The SiC precursor, AHPCS, has also been used recently, along with other polymeric precursors, to make two-phase (SiC/C and SiC/BN) amorphous ceramics that exhibit unusual microstructures and thermal/mechanical properties. These microstructures are formed during the mixing and thermosetting of the constituent polymers, which undergo phase separation due to their immiscibility. Certain of the SiC/C composites, which have the C phase uniformly distributed as ca.1-µm droplets in a SiCx matrix, exhibit high oxidation resistance, and microindentation tests on the SiC/BN system suggest unusual toughness.
Engineering and chemistry of the glass melting process
Authors: Nemec L. 
Published: October 2007

Abstract
Improved glass-melting technology, intelligent process control, glass quality control, and establishing novel melting conditions, are realized by different kinds of physicochemical models. The model application is preceded by the analysis of homogenization processes, i.e., heating, dissolution, or vitrification and refining. The energy consumption of the process, the pull rate and size of the melting space, and glass quality are the main technological factors taken into account. In the following step, the optimum conditions are applied to simplified and complex models or processes. The mentioned models are mostly represented by systems containing melt and numerous inhomogeneities (solid particles, bubbles).
Hydrothermally treated cement-based building materials. Past, present, and future
Authors: Ray A. 
Published: October 2007

Abstract
Hydrothermally cured or autoclaved cement-based building products have provided many challenges to researchers, manufacturers, and users since their inception nearly 100 years ago. The advantages, including the development of high strength within a few hours and a reduction of drying shrinkage, of the hydrothermal curing process have resulted in a variety of building products; inevitably, the technology of their production has undergone many stages of refinement. With the advent of nonconventional starting materials for the production of modern cements, and the push to utilize renewable resources to form blended cements, the chemical and physical make-up of hydrothermally cured building materials have changed considerably in recent years and will continue to change. It is, therefore, important to understand the chemical reactions taking place in an autoclave, and the consequent phase developments, if building materials produced by this process continue to be successful in the long term. A wide range of analytical techniques exists for characterizing the phase development in cement-based materials. The purpose of this paper is to illustrate the strength of thermal methods, especially when used in combination with other analytical techniques, in the understanding of hydrothermal reactions.
Effects of iron oxidation states on the surface and structural properties of smectites
Authors: Stucki J. W. , Lee K. , Zhang L. , Larson R. A. 
Published: October 2007

Abstract
The oxidation state of iron (Fe) in the crystal structure of smectite clay minerals profoundly alters their physical-chemical properties. Among the properties affected are layer charge, cation exchange and fixation capacity, swelling in water, particle size, specific surface area, layer stacking order, magnetic exchange interactions, octahedral site occupancy, surface acidity, and reduction potential. Also affected is the surface chemistry of the clay, which alters clay–water and clay–organic interaction mechanisms. Rates and extents of degradation of pesticides are increased in the presence of reduced smectites compared to oxidized and reduced-reoxidized counterparts. A hypothesis regarding the mechanism for Fe reduction in clay minerals was first developed in 1963, and subsequent modifications have been proposed periodically through the present time. Recent studies clearly reveal that the process of Fe reduction involves more than the mere transfer of an electron to octahedral Fe(III) in the clay crystal. Ancillary reactions occur that produce significant structural modifications, some of which are reversible and others of which are not. Such changes in the crystal-chemical environment of structural Fe are thought to play a dominant role in altering the clay surface chemistry.
Examples of molecular switching in inorganic solids, due to temperature, light, pressure, and magnetic field
Authors: Varret F. , Bleuzen A. , Boukheddaden K. , Bousseksou A. , Codjovi E. , Enachescu C. , Goujon A. , Linares J. , Menendez N. , Verdaguer M. 
Published: October 2007

Abstract
We describe various molecular switching processes occurring in several types of inorganic solids: spin cross-over (SC) compounds, photomagnetic Prussian blue analogs (PBAs), and valence-tautomeric system. Their thermo-, photo-, piezo-, and magneto-chromic properties are illustrated by recent examples. A common description of their static properties by a two-level model is given.
Measurement of pH. Definition, standards, and procedures (IUPAC Recommendations 2002)
Authors: Buck R. P. , Rondinini S. , Covington A. K. , Baucke F. G. K. , Brett Christopher M. A. , Camoes M. F. , Milton M. J. T. , Mussini T. , Naumann R. , Pratt K. W. , Spitzer P. , Wilson G. S. 
Published: October 2007

Abstract
The definition of a “primary method of measurement ” has permitted a full consideration of the definition of primary standards for pH, determined by a primary method (cell without transference, Harned cell), of the definition of secondary standards by secondary methods, and of the question whether pH, as a conventional quantity, can be incorporated within the internationally accepted system of measurement, the International System of Units (SI, Système International d’ Unités). This approach has enabled resolution of the previous compromise IUPAC 1985 Recommendations [Pure Appl. Chem.
57, 531 (1985)]. Furthermore, incorporation of the uncertainties for the primary method, and for all subsequent measurements, permits the uncertainties for all procedures to be linked to the primary standards by an unbroken chain of comparisons. Thus, a rational choice can be made by the analyst of the appropriate procedure to achieve the target uncertainty of sample pH. Accordingly, this document explains IUPAC recommended definitions, procedures, and terminology relating to pH measurements in dilute aqueous solutions in the temperature range 5-50 °C. Details are given of the primary and secondary methods for measuring pH and the rationale for the assignment of pH values with appropriate uncertainties to selected primary and secondary substances.
Evolution of the secondary metabolite versus evolution of the species
Authors: Pietra F. 
Published: October 2007

Abstract
Four stereochemical series of diastereomeric polyhalogenated chamigrane sesquiterpenes -headed by obtusol, isoobtusol, rogiolol, and cartilagineol- suggest the existence of four lineages of red seaweeds in the genus Laurencia.On another front, concerning marine ciliates, euplotane sesquiterpenes characterize worldwide the morphospecies Euplotes crassus, well differentiated from Euplotes raikov, Euplotes rariseta, and Euplotes vannus, which furnish different-skeleton sesquiterpenoids, and the latter also C30-backbone isoprenoids. The latter three morphospecies, however, show polymorphism in the variability of their isoprenoids.