bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gel Point
Authors: Henning Winter H. 
Published: October 2003

Abstract

The liquid‐to‐solid transition in soft materials is marked by the gel point (GP). AT GP, long‐range connectivity in the material diverges to infinite size. The connectivity can have many origins, mostly either network formation or growth of glassy states that suppress the local mobility. Growth of connecticity is slow for most soft materials, while loss of connectivity (reverse gelation) can occur rather rapidly. Materials at their GP, called “critical gels” exhibit universal features that merge liquid and solid characteristics into a unique behavior: (
1
) stress requires an infinite time to relax and (
2
) relaxation occurs in a broad, self‐similar distribution of shorter modes. These features become apparent in rheological experiments that probe the long‐time behavior. The broadening of the spectrum has been attributed to two effects, the broadening of the cluster size distribution (molecular clusters, supramolecular clusters) and the branching of the clusters. Many soft materials, namely in food, pharmaceuticals, photographic media, adhesives, vibration dampeners, and superabsorbers (to name a few), are close to their GP, ie, they are liquids just before reaching their GP or they are solids that have barely passed the GP. The GP serves as reference for developing such materials.
Carbon Black
Authors: Wang Meng‐Jiao , Gray Charles A. , Reznek Steve R. , Mahmud Khaled , Kutsovsky Yakov 
Published: October 2003

AbstractCarbon black is a generic term for an important family of products used widely to modify the mechanical, electrical, and other physical properties of the medium in which it is dispersed. It is the most widely used nano‐material, with particle dimensions ranging from tens of nanometers to a few hundred nanometers. It plays a major role in elastomers, plastics, paints and inks as a reinforcing agent, a black pigment, and an electrically conductive material. This article is an extensively revised and updated version of an article published in 1992. It provides a comprehensive review of the technical and commercial aspects of carbon black usage. The history of carbon black, its microstructure, chemical composition, morphology, surface activity, and characterization are discussed. The mechanism of carbon black formation and its manufacture, including oil‐furnace black process, thermal black process, acetylene black process, lampblack process, and impingement black process, is described. A separate section is included on newly developed surface modification technologies and related commercial applications. One section is devoted to the properties, applications, and markets of the two main types of carbon blacks, rubber grades, and special grades. The rubber grades are primarily used as a reinforcing agent in tire and other rubber products to improve their mechanical properties. Most of the special grades are manufactured to meet specific product specifications for imparting certain properties required by the end‐use products, such as dispersion, pigmentation, and electrical conductivity. The health, safety, and environmental section includes a summary of recent health studies.
Polyester Films
Authors: MacDonald W. A. 
Published: October 2003

Abstract
The manufacturing process for poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) films is described. The film properties of PET and PEN films are discussed and compared. The methods used to modify film properties such as coating, fillers, and coextrusion and how the properties of polyester films are exploited in application are described.
Silane Coupling Agents
Authors: Blum Frank D. 
Published: October 2003

Abstract
Silane coupling agents are often used to improve the properties of composite materials by modifying interfaces. The coupling agents typically contain trichloro, trimethoxy, or triethoxy groups attached to silicon at one end. These inorganic groups hydrolyze, condense, and adsorb at oxide interfaces to form a bond with the coupling agents. The other end of the molecule typically contains organofunctional groups that are chosen to react or to be compatible with an organic polymer resin. The coupling agents are particularly effective for improving the mechanical properties of composites when water is present. The appropriate selection of the coupling agent is of importance for optimal improvement of the mechanical properties of the composite materials. Factors to be considered are the type of chemical bonding desired, compatibility between the coupling agent layer and resin, and the mechanical properties of the interphase.
Environmentally Degradable Plastics
Authors: Stevens E. S. 
Published: October 2003

AbstractThe relationship between plastics and the environment is a topic of current interest to government agencies, the plastics industry, and the general public. During the 1990s, standardization organizations (ASTM, CEN, ISO) defined terms such as degradable, biodegradable, and compostable, and developed specifications for labeling prerequisites; ISO began to formulate life‐cycle assessment (LCA) programs. In some applications (eg, agricultural mulching film and compost bags) biodegradability and compostability serve intrinsic functional purposes; in others (eg, packaging, food service items, and consumer products) they allow disposal by composting, thereby avoiding incineration and landfilling.Activated polyolefins degrade, but by current standards are not compostable. Petroleum‐based synthetics that are biodegradable and compostable include poly(vinyl alcohol), poly(glycolic acid), and polycaprolactone; synthetic copolyesters and poly(ester amides) are biodegradable, some are compostable. Commercialized polymers obtained from renewable resources (biomass) include cellulose, starch, poly(lactic acid), microbial polyhydroxyalkanoates, and polymerized vegetable oils. LCA has shown that many of these polymers have lower environmental impacts than conventional petroleum‐based plastics. Their properties can be varied through the use of derivitization, additives, and blends. Many other polymeric materials have been studied in the laboratory but not yet commercialized. The future prospects for green plastics depend on technological developments that enhance environmental attributes, improve performance, and lower costs.
Poly(p‐phenylenevinylene)
Authors: Wolf Michael O. 
Published: October 2003

AbstractThis article provides an overview of the methods by which PPV and some of its derivatives may be prepared, the physical and electronic properties of these materials, and the applications that are being explored.Poly(p‐phenylenevinylene) (PPV) and its derivatives are polymers with potential applications in optoelectronic devices. PPV is a conjugated polymer. Many conjugated polymers are known and exhibit remarkably high electrical conductivities when oxidatively or reductively doped. Much of the early research on PPV focused on the relatively disappointing properties of the doped material; however, interest in this material was reawakened in 1990 when it was discovered that films of undoped PPV could be used as the emitting layer in organic electroluminescent (EL) devices. This discovery stimulated intense research in the area, including many fundamental studies of the properties of PPV and its derivatives, and extensive academic and industrial interest in the applications of the materials.
Nanocomposites, Metal‐Filled
Authors: Carotenuto G. , Nicolais L. 
Published: October 2003

AbstractBecause of surface effects and the dramatic changes in properties that occur when the critical length governing some phenomenon (eg, magnetic, structural) becomes comparable with size, metal clusters have unique characteristics (eg, plasmon absorption, near‐IR photoluminescence, superparamagnetism). The embedding of metal clusters into polymeric matrices represents a simple way to take advantage of mesoscopic metal characteristics. Polymer‐embedded metal clusters represent a new class of advanced composite materials that may find important applications in different technological areas.
Thermochromic Polymers
Authors: Seeboth Arno , Lötzsch Detlef 
Published: October 2003

AbstractThis paper presents an overview of the preparation, characterization, and potential application of thermochromic polymers. The termthermochromicdescribes materials which vary their color, color intensity, or transparency in response to temperature changes. Thermochromic effects have been observed in different types of polymer systems such as pure polymers, cross‐linked polymeric networks, polymer blends, and gels, whereby the origin of the thermochromic effect can be multifarious. The color can appear owing to absorption or owing to the physical effect of materials on light. The latter is called physical color and includes scattering and diffraction of light. Research in the field of thermochromic polymers has led to the discovery of novel effects producing thermochromism as well as to the development of thermochromic polymers with improved material properties. Moreover, rational design and optimization with a view to specific applications has started. Selected examples of the different classes of thermochromic polymers are presented and their characteristic material properties and potential applications are pointed out.
Imaging Applied to the Geologic Sciences
Authors: Arvidson Raymond E. , Guinness Edward A. , Stein Thomas , Niebur Curt , Larsen Kristopher 
Published: October 2003

AbstractGeology can be defined as the study of the nature and dynamics of planetary surfaces and interiors. This field of endeavor has expanded greatly over the past few decades to include study not only of the Earth, but also of other objects in the solar system, focusing heavily on Earth's Moon, Venus, and Mars. Acquisition and analysis of imaging data have been central to increased understanding of planetary surfaces. In the case of the planets and satellites, imaging data have been of fundamental importance because of the very limited opportunities for human exploration, return of samples, or even detailedin‐situanalyses. For Earth, analyses of image data have been central to several emerging fields of interest. In this article, the focus is on key scientific objectives associated with the geology of the Earth and how appropriate imaging data sets will help meet those objectives. This focus is not meant to downgrade the importance of imaging in robotic or human exploration of the solar system. Rather it is meant to provide a coherent theme for the article and to delineate how imaging will help address a suite of fundamentally important objectives and challenges that face us over the next few decades.The article begins with an overview of remote sensing as applied to geology, focusing on imaging applications. Summaries of objectives and tasks based in part on plans put together by the United States Geological Survey for the next decade follow. These plans both focus the key scientific areas of research within geology that have significant societal benefits and provide a coherent pathway for discussing uses of imaging in geology. Specific examples are given for the major objectives to illustrate the use of imaging techniques to address particular applications.
Imaging Science in Medicine
Authors: Hendee William R. 
Published: October 2003

Abstract
The use of imaging technologies has expanded tremendously in medicine over the past two decades. This expansion reflects the evolution of new imaging tools that reveal human anatomy and physiology in ever‐increasing detail, as well as the development of digital data acquisition and processing techniques that extract information from human tissues in ever‐expanding degrees of subtlety. A further factor that is stimulating growth in imaging is the expansion of knowledge about biological systems at the cellular, molecular, and genetic levels. This factor is transforming medical imaging from a “technology‐push” discipline into one where fundamental biological questions, as well as important clinical issues, are the force driving development of new imaging technologies. This transformation demands enhanced knowledge about the interface between biological properties of tissues and the characteristics of imaging systems. Exploration of the existing state of knowledge about the interface, and what is needed for the immediate future, is the subject of this article.
Ultrasound Imaging
Authors: Rao Navalgund A. H. K. 
Published: October 2003

Abstract
Ultrasound is defined as sound waves whose frequency is above 20 kHz, the upper limit of the human audible range. The past century has witnessed the growth of an imaging technology that uses ultrasound as the information carrier. A physical medium is required to sustain longitudinal and transverse ultrasound waves. The imaging can be passive, when the object to be detected is the source of sound, or active, when an external deliberately controlled source of sound is used and the echoes from objects in the medium are used to generate an image. State‐of‐the‐art active systems can launch waves into a medium and nondestructively collect echo signals and display information pertaining to the inside of an optically opaque three‐dimensional object. In medical applications, the propagation medium is soft tissue. Present day technology permits real‐time (20 or more image frames per second) visualization of the gross anatomy and pathology. Medical ultrasound has found applications throughout the breadth of diagnostic investigations that includes obstetrics, gynecology, abdomen, ophthalmology, cardiovascular system, breast, and superficial structures. Besides medical applications, ultrasound is also used in nondestructive evaluation (NDE) and sound navigation and ranging (SONAR). NDE is commonly used in the aerospace and nuclear power industries to inspect safety‐critical parts for flaws during in‐service use. The medium here is generally solid material. SONAR pertains to imaging under the sea. The imaging techniques and technologies used in these different application areas are quite similar, at least for medical and NDE. Therefore, the main body of the discussion centers on medical imaging.
An ultrasound imaging system usually conveys information about echo generating objects. The image can be thought of as a display of the multidimensional spatial distribution of some object‐dependent entity. Visualization of this information is one of the objectives, and perhaps the major objective in medical ultrasound. The image value is generally related to the mechanical or elastic property of the object. A secondary objective therefore is to understand and quantify the relationship between the image value and the object property, also known as quantitative imaging or tissue characterization in medical ultrasound. This area still remains a subject of active research. This article deals only with the first objective.
The three steps involved in the imaging process, namely, transduction and reception by the transducer, two‐way propagation in the medium to some depth, and the scattering/reflection phenomenon are considered in detail. Different modes of scanning and information display employed in medical diagnosis and NDE are considered.
X‐Ray Fluorescence Imaging
Authors: Chang Shih‐Lin 
Published: October 2003

AbstractIn Wilhelm Conrad Röntgen's cathode‐ray‐tube experiments, the lighting up of a screen made from barium platinocyanide crystals due to fluorescence led to his discovery of X rays in 1895. Subsequent investigations by Röntgen and by Straubel and Winkelmann showed that the radiation that emanated from a fluorspar, or fluorite crystal CaF2excited by X rays is more absorbing than the incident X rays. This so‐called fluorspar radiation is X‐ray fluorescence. Nowadays, it is known that X‐ray fluorescence is one of the by‐products of the interaction of electromagnetic (EM) waves with the atoms in matter in the X‐ray regime (0.1–500 Å).X‐ray fluorescence is a two‐step process; X‐ray absorption (the ejection of an inner electron) and X‐ray emission (the recapture of an electron). Both involve the electron configuration of atoms in the irradiated material.An X‐ray fluorescent image is usually obtained by following these steps: The incident X‐ray beam, after proper monochromatization and collimation, impinges on a sample of interest. An absorption spectrum is acquired by scanning the monochromator to identify the locations of the absorption edges of the element investigated. The incident beam is tuned to photon energies higher than the absorption edges so that the constituent elements of the sample are excited. Then, X‐ray fluorescence emanates. The spatial distribution of the fluorescent intensity, the fluorescent image, is recorded on a two‐dimensional detector or on a point detector using a proper scan scheme for the sample. The following items need to be considered for good quality images of high spatial and spectral resolution: (1) appropriate X‐ray optics for shaping the incident beam and for analyzing the fluoresced X rays and (2) a suitable scanning scheme for the sample to cross the incident beam. In addition, image reconstruction of intensity data versus position is also important for direct mapping of the trace elements in a sample.
Photoconductor Detector Technology
Authors: Melnyk Andrew 
Published: October 2003

AbstractPhotoelectric detectors are semiconducting devices that convert optical signals into electrical signals. They rely on the quantum nature of matter, whereby incident photons, ranging from high energy gamma rays through visible light to infrared rays, excite electrons in matter to produce an electrical charge. The operation of a photoelectric detector involves two steps: (1) conducting charge generation by an incident light photon and (2) charge transport and/or multiplication by whatever current gain mechanism may be present. Photoelectric detectors are classified as photoemission and photoconductive detectors. Photoemission occurs when the energy of the photonhν is sufficient to eject an electron from the surface of the solid into vacuum, and the phenomenon is the basis for photomultiplier tubes. Photoconductivity, sometimes referred to as internal photoemission, is observed in a solid when the absorbed photon raises an electron from a nonconducting energy state to a conducting energy state where it contributes to electrical conductivity.This article on photoconducting detectors explains the fundamental concepts of photoconductivity and describes the elementary photoconducting devices, their design, materials, and how they work. Except for two, photodectors incorporated in specific imaging devices and an explanation of their operation are not considered here because they are discussed in other sections on specific applications such as UV or IR detectors, CCD imagers, etc. The exceptions are electrophotographic and vidicon‐type television camera photoconductors that can be understood only as imaging devices. In contrast to other imaging photodetectors, electrophotographic photoconductors are not covered in any other sections. For this reason and because they differ significantly in their design, materials and operation from the other photodetectors, most of this section is devoted to a detailed discussion of electrophotographic photoconductors.
Oral‐facial‐digital syndrome VII is oral‐facial‐digital syndrome I: A clarification
Authors: Nowaczyk Malgorzata J.M. , Zeesman Susan , Whelan Donald T. , Wright Victoria , Feather Sally A. 
Published: October 2003

AbstractWe report on further clinical findings in the one single family in the literature classified as oral‐facial‐digital (OFD) type VII in order to demonstrate that the diagnosis in this kindred should, in fact, be OFD type I. The mother and the daughter described in the original report have since developed polycystic kidney disease. In addition, the daughter recently had a daughter of her own with central nervous system, oral and digital anomalies. Linkage studies have shown that all the affected women share the same haplotype across the previously identified region Xp22.2p22.3 to which OFD I maps. Although the pedigree was too small for a significant lod score, the combination of clinical and molecular information clearly shows that the disease in this family is OFD I. We report this family in order to clarify and simplify the classification of the oral‐facial‐digital syndrome spectrum and to recommend the removal of OFD VII from the classification system of the oral‐facial‐digital syndromes. © 2003 Wiley‐Liss, Inc.
MECP2 gene mutations in non‐syndromic X‐linked mental retardation: Phenotype–genotype correlation
Authors: Gomot Marie , Gendrot Chantal , Verloes Alain , Raynaud Martine , David Albert , Yntema Helger G. , Dessay Sabine , Kalscheuer Vera , Frints Suzanne , Couvert Philippe , Briault Sylvain , Blesson Sophie , Toutain Annick , Chelly Jamel , Desportes Vincent , Moraine Claude 
Published: October 2003

AbstractNon‐syndromic X‐linked mental retardation (MRX) is a frequent cause of inherited mental retardation. It is a heterogeneous condition in which the first 12 genes discovered to date explain no more than 15% of the MRX situations ascertained by recurrence in multiplex families. In Rett syndrome (RTT), an X‐linked dominant condition mostly sporadic and usually lethal in males, most affected females have been shown to be mutated in the Methyl–CpG binding protein 2 gene (MECP2) that maps at Xq28. Some mentally retarded males related to RTT females carry the same mutation. Several MRX families mapping to Xq28 were subsequently tested for MECP2 and a causative mutation was discovered in three families, suggesting that it could be one of the main genes involved in MRX. We report here the corresponding phenotypes in these three families of increasing severity. In family 1, an in‐frame deletion ΔP387‐M466 was found in the 3′ region. The patients had severe to mild non‐progressive MR, with better motor skills than verbal abilities. In family 2, an Arg to Trp substitution (R167W) was found between the transcription repression domain (TRD) and the methyl binding domain (MBD). The patients had brisk reflexes and essential tremor with mild and non‐progressive MR, poor motor co‐ordination and written language difficulties. In the third family (MRX16), a Glu to Gly substitution (E137G) was found in the MBD. The patients had manifestations similar to those of family 2, but MR was mild to moderate, speech articulation was poor and some had verbal stereotypies. Regression of language skills was suspected in three patients. Phenotype–genotype correlation could thus be suspected and is discussed in these three families. © 2003 Wiley‐Liss, Inc.